1.1

– Responses to Public Comments on General Comments

This file contains responses to public comments on general comments (comment codes
1000 to 1390). This section includes comments on the terminology and definitions used
in the rule, the proposed regulatory text, the need for flexibility or stringency, and other general comments on geologic sequestration.

Note that most comments on regulatory text (comment cod e 1240) are not included here but are presented in other sections to which they pertain (e.g., comments on the rule language for mechanical integrity testing are in section 2.5). However, a few

comments on the regulatory text are included here in section 1. 1.1.3 because they do

not pertain to any other aspects of the rule.

The table below presents all of the EPA

‐ assigned comment codes that are included in this section of the comment and response summary. Use the bookmarks in the PDF to

move among the comment codes.

Topics included in this summary an d associated comment codes
Topic Code

1. General and Administrative Comments 1000

1.1 General comments about the rulemaking 1200

1.1.1 Comments about the proposed rule 1210

1.1.1.1 Terminology and definitions 1220

1.1.1.2 General comments on the regulatory text 1230

1.1.1.3 Suggested changes/edits to rule language 1240

1.1.1.4 Flexibility is needed (performance

‐ based standards) 1250

1.1.1.5 More certainty/stringency is needed 1260

1.1.2 Comments on other rules/issues 1270

1.1.2.1 General comments on climate change/ global warming 1280

1.1.2.2 Comments that EPA should regulate CO2 as a pollutant 1290

1.1.2.3 Comments on other aspects of CCS (capture, transport) 1300

1.1.2.4 Comments on other "out of scope" issues, e.g., pore space ownership 1310

1.1.3 General comments about GS 1320

1.1.3.1 Support use of GS in general 1330

1.1.3.2 Oppose use of GS in general 1340

1.1.3.3 Comments on the need for GS technology 1350

1.1.3.4 Effectiveness of trapping mechanisms 1360

1.1.3.5 US storage capacity 1370

1.1.3.6 Deployment of GS 1380
1.1.4 Comments on materials in the rulemaking docket ( No comments were submitted for this topic.) 1390

Every comment on these topic areas and the associated response is included in this

summary; there is some repetition where multiple commenters made the same
comment.Responses to letters from individual commenters or organizations are also available in the rulemaking docket.Comment Code: 1000 1. General and Administrative Comments



### Individual Comments

Other EPA Comment Codes and Descriptions: 1330 1.1.3.1 Support use of GS in general Comment: ODEC supports the comments of the Ca rbon Capture and Sequestration Alliance (CCS, or the Alliance) on the proposed UIC regulations. The CCS Alliance is a coalition of entities, spanning a number of economic sectors, that share a common interest in removing impediments to investment in and development of CCS, as well as mitigating the potential risks associated with the deployment ofthis technology.[l] Its purpos e is to promote development of policy by the states and the federal government to appropriately ad dress risks and potenti al liabilities, thereby enabling the further development and increased deployment of CCS. The CCS Alliance believes these technologies can be developed while protecting underground water resources, significantly reducing global and U.S. greenhouse gas ("GHG") emissions, and enhancing u.s . energy security. The Alliance's
p urpose is to consider ways ofpromoting the development and use ofCCS technologies and to support effOlis by th e private sector, states, the federal government, non- governmental organizations and others, to help ensure that these technologies can be de veloped and widely, efficien tly and cost-effectively deployed.

Response: EPA clarifies that the purpose of the UIC GS regulation is to ensure that GS is conducted in a manner that protects USDWs from endangerment. EPA agrees that GS is one technology in a portfolio of options, including energy conserva tion, efficiency improveme nts, and the use of alternative fuels and renewable energy sources, th at could be deployed to reduce CO2 emissions.

Please see the remainder of EPA’s responses to this comment, and CCS Alliance’s comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and
p reamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1330 1.1.3.1 Support use of GS in general Comment: To whom it may concern:

I appreciate the opportunity to provide comments on the proposed rules for federal management of geologic sequestrati on of CO2 in DocketID No. EPA-HQOW-2008-0390. This is a unique opportunity to broaden our national public policy foundation by melding new federal ener gy policy with responsible natural resource policy and, in so-doing, expand economic opportunities and potentially reduce the amount of CO2 that is introduced into the atmosphere. As currently written, provisions of the proposed rules re lated to the suitability of specific reinjection locations ca use serious concern.

W y omin g has been proactive in its stewards hip of all state resources and we Commenter Name: Kenneth Alexande r Letter ID: 0146 Commenter Or g anization: Old Dominion Electric Cooperative (ODEC) Comment ID: 21726

Commenter Name: Dave Freudenthal Letter ID: 0150 Commenter Or g anization: State of W y omin g Comment ID: 22216recognize the need for environmental regulation. Over the years we have demonstrated our regulatory capabilit y by meeting and often exceeding EPA standards in managing activities that impact public health, public safety and all public resources. We are eager to co llaborate with the federal government yet again, to craft rules that work not only for the interests of the nation but that also work dire ctly for the people of Wyoming. Within the framework of this collaborative undertaking, the importanc e of including local expertise and knowledge into the regulation of CO2 sequest ration is necessary to ensure public safety while also providing new grow th opportunities for a vibrant new industry.

Response: EPA recognizes the importance of states having primacy for GS wells given the variety of geologic settings in which GS will be applied. EPA recognizes that Stat e, Tribal, Territorial, and DI UIC
p rogram Directors are in the best position to evaluate the unique issues related to well depth, geology, and hydrogeology that are posed by a Class VI well. Some degree of flexibility is needed for Class VI wells because each decision made will be site-specifi c and conditions will differ from state to state. The GS rule balances the need for these site-speci fic decisions with the n eed for minimum Federal requirements to ensure national consistency while ensuring the protection of USDWs.

EPA also believes that providing states the fl exibility to obtain prim acy for Class VI wells independently of other well classes can help foster effective ma nagement of CCS. EPA believes that allowing independent Class VI primacy may encourage states to take responsibility for implementation of Class VI regulations and provide for a more co mprehensive approach to managing CCS projects by
p romoting the integration of GS activities under SDWA into a broader framework for managing CCS. Furthermore, GS operations involve ancillary activ ities (e.g., pipeline operations, pore space ownership, land use rights, and surface access) fo r which states can call upon other aut horities that exist at the state level (but outside UIC au thority) to provide a mo re comprehensive CCS management approach. The Agency will allow independent primacy for Class VI wells under §145.1(i) of the final GS rule.

For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket. EPA is using an adaptive approach to regulating GS.

Comment: Geologists, geochemists and geophysicis ts from both the public and private sectors have been researching and analyzing Wyoming geology for nearly a century. Their work provides a rich database and a solid foundation of specific attributes for underground geologic struct ures and systems. Our reliance on natural resource development in Wyoming has closely tied our economic livelihood to these endeavors, and ther e is a wealth of local expertise and knowledge about Wyoming geology which should be factored into any fede ral rulemaking regarding CO2 sequestration.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulema king docket. EPA is using an adaptive approach to regulating GS. Commenter Name: Dave Freudenthal Letter ID: 0150 Commenter Or g anization: State of W y omin g Comment ID: 22217

Commenter Name: Dave Freudenthal Letter ID: 0150Comment: For economic and regulatory purposes, the regulations as proposed will make geological sequestration of CO2 nearly im possible. Overarchi ng CO2 sequestration regulations which do not provide an opport unity to use Rocky Mountain Laramide geology will make it extrem ely difficult to mitigate the effects of greenhouse emissions on climate change in th e West. I ask that you adopt the recommendations of the WSGS, and if you have further questions regarding the WSGS recommendations, pleas e contact Ron Surdam, the Wyoming State Geologist (phone: 307.766.2286).

I look forward to a strong and effective pa rtnership with the EPA in order to
p romulgate regulations govern ing CO2 sequestration that meet both the interests of the federal government and the state of Wyoming. Thank you for your careful consideration of our comments regarding the proposed rules and their importance.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: The MGA would like to address a few areas of the proposed rule within the context of the goals and objectives of the Platform. The MGA goals include:

• A model regional regulatory framework for CCS by 2010;

• A multi-jurisdictional pipeline sited a nd permitted to transport CO2 from a source to an appropriate reservoir for use in an EOR project by 2012;

• At least 7 pre and post-combustion coal plants with CCS in operation by 2015;

• All new coal gasification and coal comb ustion plants will capture and store CO2 emissions by 2020; and

• The region’s fleet of coal plants will have transitioned to CCS by 2050.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

EPA clarifies that permitting of co al plans and pipelines is outside the scope of the GS rulemaking. Rather, the purpose of the GS regulation is to ensu re consistency in permit ting underground injection of CO2 at GS operations across the United States a nd provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: Thank you for your efforts to facilitate geologic seque stration. We respectfully request y our consideration of our comments. Commenter Or g anization: State of W y omin g Comment ID: 22220

Commenter Name: M. Michael Rounds Letter ID: 0159 Commenter Or g anization: Midwestern Governors Association (MGA) Comment ID: 22225

Commenter Name: M. Michael Rounds Letter ID: 0159 Commenter Or g anization: Midwestern Governors Association (MGA) Comment ID: 22232Sincerely,

M. Michael Rounds, Governor of South Dakota a nd Chair, Midwestern Governors Association

Jennifer Granholm, Governor of Michigan and Vice Chair, Midwestern Governors Association

cc: Lee Whitehurst, Office of Ground Water & Drinking Water

444 North Capitol Street, NW Suite 401 Washington, DC 20001-1512 Tel:202.624.5460 Fax: 202.624.5452 Regional Office 701 East 22nd Street Suite 110 Lombard, Illinois 60148 Tel: 630.925.1922 Fax: 630.925.1930 www.midwesterngovernors.org

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: It appears that GS of CO2 from fossil-fu eled power plants will be a necessary
p art of any national strategy to control green house gas emissions. San Miguel, operates coal-fired power plants and these plants are likely to be directly affected by new GS regulations. The regula tions could have significant financial and operational impacts on San Miguel and we ask EPA to carefully consider our comments because of the significant stak e we have in the outcome of this important rulemaking. San Miguel is a memb er of the National Rural Electric Cooperative Associati on ("NRECA"). NRECA will also be submitting comments on the
p roposed UIC rules. San Miguel supports NREC A’s comments, and incorporates them here by reference.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment and NRECA’s comments for further deta ils. For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

EPA agrees that GS is one technology in a portfolio of options, including solar, wind, biomass, and geothermal, that could be deployed to reduce CO2 emissions; however these technologies are outside the scope of the UIC GS rulemaki ng. The Class VI GS requirements ar e designed to ensure consistency in permitting underground in jection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Other EPA Comment Codes and Descriptions: 5400 2.9 Proposed Financial Responsibilit y and Commenter Name: Joseph Eutizi Letter ID: 0161 Commenter Or g anization: San Mi g uel Electric Cooperative, Inc Comment ID: 21282

Commenter Name: James Stine Letter ID: 0163 Commenter Or g anization: National Rural Electric Cooperative Association (NRECA) Comment ID: 21318Long-Term Care Requirements Comment: Principles for Managing Liability

N RECA is a member of the Carbon Capture and Storage Alliance (CCS or the Alliance) and this group is planning to submit comments on the proposed UIC rules for GS of CO2.

The CCS Alliance is a coalition of en tities, spanning a number of economic sectors that share a common interest in removing impediments to investment in and development of carbon captu re and storage ("CCS"), as well as mitigating the
p otential risks associated with the de ployment of this technology. Its purpose is to promote development of policy by th e states and the federal government to appropriately address risks and potential liabilities, thereby enabling the further development and incr eased deployment of CCS. Th e CCS Alliance believes these technologies can be develope d while protecting underground water resources, significantly reducing gl obal and U.S. greenhouse gas ("GHG") emissions, and enhancing U.S. energy se curity. The Alliance’s purpose is to consider ways of promoting the developm ent and use of CCS technologies and tosupport efforts by the private sector, states, the federal government, nongovernmental organizations and others, to help ensure that these technologies can be developed and widely, efficiently and cost-effectively deployed.

We support the comments of the Alliance and incorporate them here by reference. N RECA is relying on the Alliance and USWAG to provide EPA with specific comments on the Financial Assurance and Long Term Liability issues discussed in the
p roposal. We are not experts on these matt ers, however we do believe that the

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional inform ation on EPA's final regulatory approach, including financial responsibility for GS wells, please see the final rule and preamble as well as the rulemaking docket.

Comment: APPA appreciates the opportunity to co mment on this important rulemaking initiative and looks forward to working wi th EPA on this effort. APPA has also filed comments on the EPA ANPR in respons e to many questions that the EPA has asked on geologic sequestration. It is crit ical that the EPA’s air, water and
p olicy offices understand that while APPA will offer reasons why geologic sequestration should not be presumed to be Clean Air Act t echnological choices under MACT, BACT, LAER, or for NSPS comp liance etc., we do strongly want the U.S. EPA to have a Class VI regulatory system that would allow for these demonstration (and later commercial scale plants) plants. APPA would be pleased to meet with the EPA regarding these issu es. We would additionally be pleased to include in any EPA meeting our partners, the American Water Works Association (AWWA) which represents the public and priv ate water utilities who have "front line" drinking water protection obligations.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For a dditional information on EPA's final re g ulator y approach, please see Commenter Name: Theresa Pugh Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23436the final rule and preamble as well as the rulemaking docket.

EPA clarifies that technologies cons idered under Clean Air Act regulati ons are outside the scope of the GS rulemaking. Rather, the purpose of the GS regulation is to en sure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. Please see the discussion, “How Does This Rulemaking Relate to the Greenhouse Gas (GHG) Reporting Program?” in the preamble.

Comment: It appears that GS of CO2 from fossil-fu eled power plants will be a necessary
p art of any national strategy to control green house gas emissions. GRE operates coal-fired power plants and these plants are likely to be directly affected by new GS regulations. The regulations could have significant financial and operational impacts on GRE and we ask EPA to carefully consid er our comments because of the significant stake we have in the outcome of this important rulemaking. GRE is a member of the National Rural Electric Cooperative Association ("NRECA") and th e Utility Solid Waste Activity Group (USWAG). Both groups will also be submit ting comments on the proposed UIC rules. GRE supports the comments of both NRECA and USWAG, and incorporates them here by reference.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional inform ation on EPA's final regulatory approach, including financial responsibility, please see the final rule and preamble as well as the rulemaking docket.

EPA agrees that GS is one technology in a portfolio of options, including solar, wind, biomass, and geothermal, that could be deployed to reduce CO2 emissions; however, these technologies are outside the scope of the UIC GS rulemaki ng. The Class VI GS requirements ar e designed to ensure consistency in permitting underground in jection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Other EPA Comment Codes and Descriptions: 5400 2.9 Proposed Financial Responsibility and Long-Term Care Requirements Comment: Comments Regarding Liability and Risk Management

GRE supports the comments of the Carbon Capture and Sequestration Alliance (CCS, or the Alliance) on the proposed UIC re gulations. The CCS Alliance is a coalition of entities, spanning a number of economic sectors, that share a common interest in removing impediments to investment in and development of carbon capture and storage ("CCS"), as we ll as mitigating the potential risks associated with the deployment of this technology.(Footnote 1) Its purpose is to
p romote development of policy by the st ates and the federal government to appropriately address risks and potential liabilities, thereby enabling the further development and incr eased deployment of CCS. Th e CCS Alliance believes these technolo g ies can be developed while protectin g under g round water Commenter Name: Erik Silvola Letter ID: 0171 Commenter Or g anization: Great River Ener gy Comment ID: 23438

Commenter Name: Erik Silvola Letter ID: 0171 Commenter Or g anization: Great River Ener gy Comment ID: 23446resources, significantly reducing gl obal and U.S. greenhouse gas ("GHG") emissions, and enhancing U.S. energy se curity. The Alliance’s purpose is to consider ways of promoting the developm ent and use of CCS technologies and tosupport efforts by the private sector, states, the federal government, nongovernmental organizations and others, to help ensure that these technologies can be developed and widely, efficiently and cost-effectively deployed.

We support the comments of the Alliance and incorporate them here by reference. GRE is relying on NRECA and the Alliance to provide EPA with specific comments on the Financial Assurance and Long Term Liability issues discussed in the
p roposal. We are not experts on these issues , however we ask EPA to consider the

Footnote 1: MidAmerican Energy Holdings Company, National Mining Association, N ational Rural Electric Cooperative Asso ciation, NRG Energy, Inc., PacifiCorp and Zurich North America.

Response: The goal of financial responsibility is to ensu re that financial resources are available to
p revent or remediate the endangerment of USDWs from improper plugging, remediation, and management of wells in the event that the owner or operator experiences fi nancial difficulties. EPA agrees that assuring financial responsibility for corrective action on wells in the AoR, injection well
p lugging, PISC and site closure, and emergency and remedial response at GS sites is an important component of ensuring that USDWs are protected. See the final rule and preamble for further discussion of EPA's final approach to financial responsibility.

Please see EPA's responses to the CCS Alli ance's comment for additional information.

Comment: Dominion has participated in the developm ent of industry comments and positions with the Edison Electric Institute (EEI) and the Utility Solid Waste Activities Group (USWAG), and supports the views expressed therei n. Additionally, Dominion is a member of the American Gas Associ ation (AGA) and Interstate Natural Gas Association of America (INGAA) and shares many of the concerns and opinions of these organizations.

While supportive of the comments of our industry peers and associations, Dominion's comments are shaped by se veral factors unique to Dominion:

(a) Dominion has substantia l coal fired assets in the northeast U.S. where geology is less conducive to GS into conventional formations;

(b) Dominion has extensive underground natural gas storage assets in West Virginia, Ohio, Pennsylvania and New York; and,

(c) Likely target formations for GS in Dominion's regulated territory are unmineable coal seams and depleted coal bed methane wells, including enhanced gas recovery from coal seams. These targ et formations, while representing only a small fraction of the total US projected storage capacity, are the most viable target formation for a signifIcant por tion of Dominion's CO2 sources. Commenter Name: Pamela Faggert Letter ID: 0175 Commenter Or g anization: Dominion Comment ID: 23512Response: EPA acknowledges that depleted oil and gas rese rvoirs associated with ER operations may be used for CO2 storage and that these sites may be some of the first sites wh ere commercial-scale GS is deployed. The rule clarifies that Class VI requirement s apply to any CO2 injecti on project (regardless of formation type) when the purpose of the project is long-term storage. Please see the remainder of EPA's responses to this comment, EEI’s comment, A GA’s comment, and USWAG’s comment for further details. For additional information on EPA's final regulatory approach please see the final rule and the discussion of site-selection criteria and target formations for GS in the preamble as well as the rulemaking docket.

Comment: Representative of our efforts, SSEB manages the Southeast Regional Carbon Sequestration Partnership (SECARB), a res earch program established in 2003 with the primary goals of identifying ma jor sources of carbon emissions, characterizing the geology of a 13-state region, determining the most promising options for commercial deployment of carbon sequestration technologies in the South, and validating the technology options through carefully executed field testing. SECARB is one of seven regi onal carbon sequestration partnerships nationwide, co-funded by the United States Department of Energy. SECARB’s membership is comprised of more than 100 active industry, government, academic, and non-profit participants.

Regarding injection issues, our areas of common interest within the partnership include:

- aquifer exemptions and prohibition on injection above underground sources of drinking water (USDWs ) (e.g. coal seams); - credit for storage in enhanced oil r ecovery (EOR)-related applications; and - transitioning from Class II EO R activities to storage only.

SSEB offers the following comments, which represent a consensus of thoughts shared by many of the SECARB techni cal partners and stakeholders.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble, includi ng the discussion of aquifer exempti ons and the repermitting of Class II/EOR wells for GS, as well as the rulemaking docket.

EPA clarifies that carbon crediti ng and green house gas accounting are outside the scope of the UIC GS rulemaking. The Class VI GS rule is designed to en sure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: The Edison Electric Institute (EEI) [FN1] submits these comments on the Environmental Protection Agency (EPA or Agency)‘s proposed regulations for the injection and geologic stor age (GS) of carbon dioxide (CO2) under the authority of the Safe Drinkin g Water Act (SDWA)'s under g round in j ection control (UIC) Commenter Name: Kenneth Nemeth Letter ID: 0176 Commenter Or g anization: Southern States Ener gy Boar d Comment ID: 23534

Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23560p rogram, issued in July 2008 (Docket ID No. EPA-HQ-OW-2008-0390), 73 Fed. Reg. 43492 (July 25, 2008). EEI submitted pre-rulemaking comments to the Agency on May 15, 2008, and provided oral and writ ten testimony at EPA‘s September 30, 2008, public hearing on the proposed rules. These comments and testimony are incorporated by reference herein.

[FN1] EEI is the national association of shareholder-owned electric utilities in the U.S. Our members represent about 70 percent of the U.S. electric power industry and serve 95 percent of the ul timate customers in the industry‘s investor-owned segment.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: With the above general principles in mi nd, EEI provides below specific comments on several aspects of the proposed rule s, focusing in particular on the following categorie s of issues:

- Siting, including the definition of US DW, and secondary containment.

- AOR and provisions for periodic reevaluation thereof.

- Monitoring and use of tracers.

- Closure and post-inj ection site care.

- Financial assurance.

- Grandfathering.

- Public participation.

- State primacy.

- Potential issues relating to the char acterization of CO2 and arising under other environmental laws.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional inform ation on EPA's final regulatory approach, including site selection criteria, AoR, moni toring, financial responsibility, and state primacy, please see the final rule and preamble as well as the rulemaking docket. Also, please see the disc ussion, “How Does This Rulemaking Relate to the Greenhouse Gas (GHG) Reporting Program?” in the preamble.

Comment: These comments are filed on behalf of th e Independent Petroleum Association of Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23574

Commenter Name: Lee O. Fulle r Letter ID: 0179 Commenter Or g anization: Independent Petroleum Associ ation of America et al. Comment ID: 23609America (IPAA), the International Associ ation of Drilling C ontractors (IADC), the International Associati on of Geophysical Contract ors (IAGC), the National Stripper Well Association (NSWA), the Petroleum Equipment Suppl iers Association (PESA), the US Oil & Gas Association (U SOGA) and the following organizations:

Arkansas Independent Petroleum a nd Royalty Owners Association California Independent Petroleum Association Coalbed Methane Association of Alabama Colorado Oil & Gas Association East Texas Producers & Royalty Owners Association Eastern Kansas Oil & Gas Association Florida Independent Petroleum Association Illinois Oil & Gas Association Independent Oil & Gas Association of New York Independent Oil & Gas Asso ciation of Pennsylvania Independent Oil & Gas Association of West Virginia Independent Oil Producers Agency Independent Oil Producers Association Tri-State Independent Petroleum Associ ation of Mountain States Independent Petroleum Association of New Mexico Indiana Oil & Gas Association Kansas Independent Oil & Gas Association Kentucky Oil & Gas Association Louisiana Independent Oil & Gas Association Michigan Oil & Gas Association Mississippi Independent Producer s & Royalty Association Montana Petroleum Association N ational Association of Royalty Owners N ebraska Independent Oil & Gas Association N ew Mexico Oil & Gas Association N ew York State Oil Producers Association N orth Dakota Petroleum Council N orthern Alliance of Independent Producers Ohio Oil & Gas Association Oklahoma Independent Petroleum Association Panhandle Producers & Royalt y Owners Association Pennsylvania Oil & Gas Association Permian Basin Petroleum Association Petroleum Association of Wyoming Southeastern Ohio Oil & Gas Association Tennessee Oil & Gas Association Texas Alliance of Energy Producers Texas Independent Producers and Royalty Owners Association Virginia Oil and Gas Association Wyoming Independent Producers Association

Collectively, these groups represent the thousands of independent oil and natural gas explorers and producers that will be the most significantly affected by the proposed actions in these regulator y actions. Independent producers have the knowhow to drill and complete wells to depths beneath America’s USDWs. They drill about 90 percent of American oil and natural gas well s, produce over 65p ercent of American oil, and more than 80 percent of American natural gas.

In addition to the specific comments ma de herein, we support those comments submitted separately by the participants in these comments.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: The proposed Class VI regulations represent an important step in ensuring that USDWs are protected during geological car bon sequestration ope rations. Clearly, very significant efforts have been made, and input has been received on many issues to craft the draft regulations. The comment pro cess now underway offers an important opportunity to review th e proposed regulations and address specifics that remain to be dealt with. With respect to suggested modifications,

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: APS would like to go on record voicing it s support of the USWAG comments and urge EPA to carefully consider USWAG's comments as it develops this program. In
p articular, APS would like to emphasize the following points, which are discussed in detail in the USWAG commen ts together with comments on several other key issues associated with the proposal.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment and USWAG’s comment for further detail s. For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: NiSource would also like to make the point that we support the comments made on the behalf of natural gas utility members by the American Gas As sociation (AGA). In particular, we would like to echo the AGA's concerns regarding the protection of geologic natural gas storage.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment and AGA’s comments for further details. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket. Commenter Name: Robert J. Finley Letter ID: 0180 Commenter Or g anization: Illinois State Geolo g ical Surve y Comment ID: 23616

Commenter Name: Scott Davis Letter ID: 0187 Commenter Or g anization: Arizona Public Service Compan y Comment ID: 25219

Commenter Name: Daniel Plath Letter ID: 0188 Commenter Or g anization: NiSource, Inc. Comment ID: 25227

Commenter Name: G. Graham Holden Letter ID: 0189 Commenter Or g anization: O g lethorpe Power Corporation Comment ID: 25241Comment: will also be submitting comments on the proposed UIC rules. Oglethorpe Power supports NRECA’s comments, and through this document incorporates those comments by reference.

We support the comments of the CCS Alli ance and incorporate them here by reference. In addition, Oglethorpe Power de fers to NRECA and the CCS Alliance to
p rovide EPA with specific comments on the Financial Assurance and Long Term Liability issues discussed in the proposal.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment, CCS Alliance’s comment, and NRECA’s comment for further details. For additional information on EPA's final regulatory approach, please see the final ru le and preamble as well as the rulemaking docket.

Comment: CSC has participated in th e development of the multi-stakeholder discussion (MSD) process leading to th e submission of a joint letter to EPA. We join the other participants in expressing our appreciation for EPA’s extension of the
p ublic comment period that allowed us to make substantial pr ogress in expanding our shared understanding on the relevant issues and to reach significant agreement on how these issues can be addressed and resolved by EPA. CSC supports all of the recommendations presented in that letter, which are submitted with the request that the recomm endations be considered as a whole because the recommendations were developed in combin ation to accurately reflect our shared understanding.

In addition, we are committed to contin uing the MSD process and to inviting others to participate with an objecti ve of developing additional specific recommendations for improveme nt of a final rule that could be adopted by EPA’s scheduled date in late 2010 or early 2011, including development of the requirements to be applied to oil and ga s reservoir geologic sequestration that is not conducted in conjunc tion with enhanced oil and gas produc tion operations. We will be working with the other MSD participants toward submission of additional recommendations by February 28, 2009.

Response: EPA acknowledges the comment. Pl ease see the remainder of EPA' s responses to this letter and those of other participants of the MSD proce ss for further details. For additional information on EPA's final regulatory approach, including involving the public in pe rmitting decisions, please see the final rule and preamble as well as the rulemaking docket.

Comment: In addition to the Multi-Stakeholde r Discussion Group mentioned above, ConocoPhillips has formulated our specifi c perspective on EPA rulemaking working with organizations including the American Petroleum Institute, the CO2 Capture and Storage (CCS) Contact Group (VanVoorhees/Bryan Cave). We support the consensus of these groups, taken in their entirety. Our company's comments Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24314

Commenter Name: Jeff W. Sheets Letter ID: 0192 Commenter Or g anization: ConocoPhillips Comment ID: 23886Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment, American Petroleum Institute’s commen t, and CCS’s comment for further details. For additional information on EPA's final regulatory approac h, please see the final rule and preamble as well as the rulemaking docket.

Comment: this sneaky kind of document from ameri can electric power is the type of document that should not be accepted by th is agency at all for publi comment. since it is NOT public comment. it attempts to do an end run around open goverment. i very much believe this agen cy needs a new policy of destroying any letters sent like this that are secret. obviously this profiteer does not want the
p ublic to know the sneaky stuff they are pr oposing. i think that is not open govt or democratic at all. star t a policy with this document of denying such communications at all. if it isnt public, it should not be accepte d as a comment. sneaky company -its disgusti ng to try to close govt.

Response: EPA addresses all comments received. Some in formation submitted, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically thr ough www.regulations.gov or in hard copy at the OW Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave., NW, Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the P ublic Reading Room is (202) 566-1744, and the telephone number for the OW Docket is (202) 566-2426.

Comment: we just had a big scandal in nj where the lab that tests the water was lying on est results. how does the public protect itself from that. it is clear that some system needs to be set up to check the labs wh ich need watching since they obviousy are turning in fake water health reports.

Response: EPA clarifies that the regulation of drinking wate r laboratories is outside the scope of the GS rulemaking. Rather, the purpose of the GS regulation is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in antici pation of the eventual use of GS to reduce CO2 emissions.

Comment: Ameren is a member of the Utility Soli d Waste Activities Group ("USWAG"), the Edison Electric Institute (" EEI"), and the Electric Power Research Institute ("EPRI)". We endorse the comments filed by USWAG, EEI, and EP RI. In addition, I
p rovided oral and written testimony on behalf of USWAG at EPA’s October 2, 2008,
p ublic hearing on the proposed rules

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment, USWAG’s comment, EEI’s comment, and EP RI’s comment for further details. For additional information on EPA's final re g ulator y approach, please see the final ru le and preamble as well as the Commenter Name: Anonymous5 Letter ID: 0194 Comment ID: 23918

Commenter Name: Anon y mous6 Letter ID: 0195 Comment ID: 23919

Commenter Name: Paul Pike Letter ID: 0198 Commenter Or g anization: Ameren Corporation Comment ID: 23937rulemaking docket.

Comment: Southern Company submits these comments on the Proposal of the Environmental Protection Agency ("EPA" or "the Agency") to establish a regulatory framework for geologic sequestration ("GS") of carbon dioxide ("C02") under the Underground Injection Control ("UIC") Pr ogram pursuant to the Safe Drinking Water Act ("SDWA"). 73 Fed. Reg. 43492 (July 25, 2008). [FN1 Southern Company also endorses the comments filed on this Proposal by the Utility Solid Waste Activities Group, Edison Electric Instit ute, and the Carbon Sequestration Council Carbon Capture and Sequestration C ontact Group.] Southern Company (NYSE: SO) is a super-regional energy company with more than 42,000 megawatts of electric generating capacity in the Southeast. Southern Company is one of the largest producers of electricity in th e country, supplying energy to a 120,000- square mile service territory spanning most of Georgia and Alabama, southeastern Mississippi, and the panhandle region of Florida and serving nearly 4.4 million customers. Southern Company is ranke d number 166 on the latest Fortune 500 listing of the largest United States corporations, with approximately 26,000 employees and reported earnings in 2007 of $1.73 billion. Southern Company owns four regulated retail elect ric utilities: Geor gia Power, Alabama Power, Gulf Power, and Mississippi Power.

In addition, Southern Company is a lead er in environmental research. Through 2007, Southern Company has invested approximately $4.6 billion in environmental controls and plans to spend an additional $3.9 billion through 2010 to further reduce emissions. Southe rn Company is committed to the deployment of a variety of energy sources including renewable ener gy. Southern Company has already begun

Response: EPA acknowledges the comment. Pl ease see the remainder of EPA' s responses to this letter for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: In addition to the following comments, Duke Energy supports the comments submitted by the Utility Solid Waste Activities Group, the Edison Electric Institute, the Electric Power Research Institute, and the Gasification Technologies Council.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment and USWAG’s comment, Edison Electric In stitute’s comment, Elec tric Power Research Institute’s comment, and the Gasification Technologies Council co mment for further details. For additional information on EPA's final regulatory approac h, please see the final rule and preamble as well as the rulemaking docket. Commenter Name: Chris M. Hobson Letter ID: 0201 Commenter Or g anization: Southern Company Comment ID: 22152

Commenter Name: Michael Stroben Letter ID: 0209 Commenter Or g anization: Duke Ener gy Comment ID: 22678

Commenter Name: Paul L. Carpinone Letter ID: 0212 Commenter Or g anization: Tampa Electric Compan y Comment ID: 23041Comment: Regulatory Group (USWAG). Tampa Electric endorses the comments filed by EEI and USWAG in this docket.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment, USWAG’s comment, and Edison Electric Institute’s comment for further details. For additional information on EPA's final regulatory approac h, please see the final rule and preamble as well as the rulemaking docket.

Comment: NDEP also supports the comments submitte d by the Association of State Drinking Water Administrators. Thank you for the opportunity to comment on this proposed rule. If you need any additional information, please contact me.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment and ASDWA’s comment for further detail s. For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: Our comments address the following important topics: (A) Enhanced Oil Recovery or Enhanced Gas Recovery ("EOR/EGR") a nd CO2 Storage; (B) Wells, Monitoring & Operations; (C) Site Closur e Period; and (D) Financial Assurance. HEI further j oins in the comments submitted by th e American Petroleum Institute.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment and API’s comments for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble, including Class II/EOR wells, testing and monitoring, operating requirements, post-injection site care, site closure, and fina ncial assurance, as well as the rulemaking docket.

Comment: Significantly, this technology does not st art on a blank slate. The Oil & Gas industry has extensive, rele vant experience with injection into the subsurface that can inform this rulemaking. Moreover, BP is a leader in studies and demonstration projects conducted around the world regarding geologic sequestration of CO2. The comm ents submitted here are in large measure based upon this significant experience and tec hnical knowledge. We would be pleased to review our comments and/or any ques tions that EPA may have regarding our comments at EPA’s convenience. HEI also welcomes the opportunity to provide additional information or input to EPA as EPA continues its evaluation and study of comments, scientific papers/studies or other information submitted or considered in this rulemaking process.

Response: EPA acknowledges the comment. EPA recognizes that the oil and gas industry has decades of experience in j ectin g CO2 for the purpose of EOR. The GS rulemakin g builds upon existin g Commenter Name: Jonathon Palm Letter ID: 0222 Commenter Or g anization: Nevada Division of Environm ental Protection, Bureau o f Water Pollution Control Comment ID: 21645

Commenter Name: Tiffan y Rau Letter ID: 0224 Commenter Or g anization: Hydrogen Energy International Comment ID: 21649

Commenter Name: Tiffan y Rau Letter ID: 0224 Commenter Or g anization: H y dro g en Ener gy International Comment ID: 21703experience and knowledge about safe injection practices in EOR and ot her injection industries, with tailored requirements that address the uni que nature of CO2 injection for GS.

Please see the remainder of EPA' s responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble, including the discussion of the repermitting of Class II EOR wells for GS, as we ll as the rulemaking docket.

Comment: Significantly, this technology does not st art on a blank slate. The Oil & Gas industry has extensive, rele vant experience with injection into the subsurface that can inform this rulemaking. Moreover, BP is a leader in studies and demonstration projects conducted around the world regarding geologic sequestration of CO2. The comm ents submitted here are in large measure based upon BP’s significant experi ence and technical knowledge. We would be pleased to review our comments and/or any questions that EPA may have regarding our comments at EPA’s convenience. BP also welcomes the opportunity to provide additional information or input to EPA as EPA continues its evaluation and study of comments, scientific papers/studies or other information submitted or considered in this rulemaking process.

Response: EPA recognizes that the oil and gas industry ha s decades of experience injecting CO2 for the
p urpose of EOR. The GS rulemaking builds upon existing experience and knowledge about safe injection practices in EOR and other injection i ndustries, with tailored re quirements that address the unique nature of CO2 injection for GS.

EPA acknowledges the comment. Plea se see the remainder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble, including the discussion of the repermitting of Class II EO R wells for GS, as well as the rulemaking docket.

Comment: Gas storage fields in the United States can be divided into two major types:
p orous rock reservoirs and salt caverns. Gas storage has been developed in many of the major sedimentary basins throughout the U.S. Because many of the areas and geologic formations considered for GS will be in the same basins and will occur in the geologic section either above, below, or in some cases, within the same formation as natural gas storage fi elds, there is a potential for natural gas storage fields to be directly or indirectly impacted by GS. Gas storage is a very important part of natural gas s upply in the U.S., because it provides up to 50% of the winter heat ing season peak consumption of 50 Bcf per day to residential and commercial customers when there is typically not enough flowing capacity in pipelines to meet the winter surge in demand.

We ask EPA to address the potential im pacts on gas storage operations in crafting the final rule with resp ect to the following issues.

Response: EPA clarifies that the Class VI requirements appl y onl y to wells that are in j ectin g CO2 into Commenter Name: Brian Williams Letter ID: 0225 Commenter Or g anization: BP Alternative Ener gy North America, Inc. (BP) Comment ID: 21764

Commenter Name: Pamela A. Lace y Letter ID: 0228 Commenter Or g anization: American Gas Associatio n Comment ID: 21802the subsurface for the purpose of GS, and not to na tural gas storage operations, and that natural gas storage operations are out of the scope of the UIC program's authority.

Please see the remainder of EPA' s responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final ru le and preamble as well as the rulemaking docket.

Comment: Id. at 49 (citing NAS, Pros pective Evaluation). We offer the foregoing comments in an effort to help ensure the safe ty and effectivene ss of geologic carbon sequestration when it is located in or near natural gas storage fields, and to ensure that the interaction of the GS well and the natural gas storage field does not pose a threat to underground sources of drinking water.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1852 1.4.2.1 DOE Regional Carbon Sequestration Partnerships Comment: Introduction and Background This document summarizes review and comm ents from Battelle researchers’ under he regulatory work of Midwest Regiona l Carbon Sequestration Partnership’s (MRCSP) on the USEPA Proposed Rule- Fede ral Requirements under UIC Program for CO2 Geologic Sequestration Wells (Doc ket ID No. EPA-HQ-OW2008-390). These comments reflect our experience in perm itting and implementing three Phase II CO2 injection tests and the MRCSP Phase III project, as well as work on several other research projects during last 12 years of CCS research at Battelle:

Table [see PDF Docket ID EPA-HQ-OW-2008-390-0229.1]

The analysis also reflects Battelle expe rience with the UIC permitting of the AEP Mountaineer CO2 storage project, which is targeting 4 years of injection of over 100,000 metric tons CO2/yr at the AEP Mountaineer plant in New Haven, WV. While the MRCSP includes over 30 differen t members, the comments expressed herein do not necessarily reflect opinions of the individual members of the MRCSP.

The MRCSP is one of seven partnerships in a nationwide effort to determine regionally-appropriate carbon sequestra tion options and opportunities. These
p artnerships are part of an overall effort by the U.S. Department of Energy’s N ational Energy Technology Laboratory (DOE/N ETL) to develop robust strategies for mitigating carbon dioxide emissions. The MRCSP was formed to assess the technical potential, economic viabilit y, and public acceptability of carbon sequestration within its Region. Commenter Name: Pamela A. Lacey Letter ID: 0228 Commenter Or g anization: American Gas Associatio n Comment ID: 21808

Commenter Name: Neera j Gupt a Letter ID: 0229 Commenter Or g anization: Battelle Energy Technology (BET) Comment ID: 21809The MRCSP region consists of eight contiguous states: Indiana, Kentucky, Maryland, Michigan, New York, Ohio, Pennsyl vania, and West Virginia. The MRCSP includes over 30 organizations from the research community, energy industry, universities, non-government, and government organizations. In the first phase of research, which took place over a two year period ending in September 2005, the MRCSP characterized ca rbon sequestration opportunities in the region. MRCSP is now involved in a four year Phase II effort that began in October 2005. This
p hase will conduct several small-scale fiel d tests of sequestration in differentlocations around the region to evaluate various sequestration options in realworld settings. The MRCSP Ph ase III project will involve sequestration of more than 1 million metric tons CO2.

Response: EPA acknowledges the value of the DOE pilot pr ojects and resultant data and information generated by such projects. EPA has evaluated perm its and reviewed operationa l data and information associated with the seven RCSPs funded by the U.S. Department of Energy and coordinated through the N ational Energy Technology Laboratory (N ETL). In addition to the inform ation cited in the preamble to the proposed rule, EPA published a No tice of Data Availability and Request for Comment on August 31, 2009 (74 FR 44802), in which the Agency described the results of research at three DOE partnership sites: the Escatawpa, Mississippi project; the Aneth Field project in Paradox Basin, Southeast Utah; and the Pump Canyon Site, New Mexico. The Agency will continue to track GS project developments and evaluate new and ongoing research and information to ensure USDW protection, including those
p erformed by the MRCSP.

EPA is using an adaptive approach to regulating GS under the UIC Program. Ev en after finalizing the rule, the Agency plans to collect and review da ta every six years on GS projects, including data generated by the partnerships, to determine whethe r the appropriate amount a nd types of information and appropriate documentation are being collecte d, and to determine if modifications to the requirements are appropriate or necessary.

Comment: Enhanced oil recovery offers the potential to vastly expand domestic crude oil reserves and production, while simultaneously providing a positive answer to CO2 emissions based on a commercial, valu e added sequestration solution. Carbon dioxide injection into mature oil fields is a proven oil recovery method that has been safely and successfully utilized for 35 years. In fact CO2 EOR was growing in the U.S. even before the rece nt crude oil price run-up, when oil was selling for $20 per barrel. The technique now accounts for about 4% of U.S. oil
p roduction.

Crude oil production has been declining in the U.S. since the early 1970’s (see Figure 1 below). Current production is about 5.2 million barrels per day (excluding natural gas condensates a nd other liquid by-products). Leading experts estimate that an additional 3.0 million daily barrels per day of American crude can be produced using CO 2, ultimately increasing domestic oil output by more than 50%. As an indicator of this potential, CO2 EOR has already stimulated rising oil production in Mississi ppi and Wyoming, where adequate, low cost sources of CO2 have been available to support growth. Unfortunately, there are substantial CO2 shorta g es in most U.S. oil basins that constrain the g rowth Commenter Name: A. James Ma y e r Letter ID: 0230 Commenter Or g anization: A. J. Mayer International on behalf of the American Ener gy Securit y Initiative Comment ID: 21871of CO2 EOR. The prospect of capturing a nd utilizing additional and substantial low cost CO2 supplies from the gasification of American coal, petroleum coke, municipal solid waste, and biomass re presents the ultimate economic and environmental leveraging of our strategic domestic energy resources. Gasification clearly offers a "next genera tion" in energy efficiency, emissions control, and fuel and chemical product manufacturing flexibility. Gasification
p lants can be configured to make one or a portfolio of transportation fuels, chemicals, fertilizers, natural gas subs titutes, and electricity, while at the same time capturing a large percentage of CO2 generated by the processes. These large new CO2 product streams represent a valuable commodity that can be utilized to restore the vitality of many of America’s mature oil fields, facilitating a rapid increase in domes tic production from stranded oil (as described below), and substantial economic and national security benefits.

Figure 1: US Oil Production Ha s Been Declining Since 1970 [see PDF Docket ID EPA-HQ-OW-2008-0390-0230]

The United States has Vast EOR Potential that is Geographically Diverse

In terms of resource base, the U.S. CO2 EOR "prize" is tremendous, with technically recoverable rese rves estimated at more than 88 billion additional barrels of oil from declining oil fields (see the attached Department of Energy fact sheet) in ten major basins. [S EE EPA-HQ-OW-2008-0390-0230.PDF FOR FACT SHEETS] In addition, experts are currently assessing another tremendous CO2 EOR target--a new class of virgin oil resources being referr ed to as "residual oil zones" or "transition zone s." Residual oil zones ("RO Zs") are untapped oilbearing geologic units beneath some main pay zones from which the easy oil has been displaced by natural underground water m ovement over the geological past (a
p rocess analogous to oil industry wate r flooding, also know as secondary recovery). CO2 injection (tertiary recovery ) into ROZs is a promising method to mobilize enough of the remaining "stranded oil" to justify development of a number of these formations.

Although somewhat difficult to quantify at this early stage, residual oil zone resources are believed to be in the bill ions of barrels, offering the potential to significantly increase th e 88+ billion barrel CO2 EOR reserve base (see the attached DOE fact sheet for more details) . Several very significant commercial residual oil zone projects are already in production in the U.S., including an operation at the Hess Seminol e Field and one at Occide ntal Petroleum’s Wasson field - both in West Texas. Other fields with substantial RO Z resources await CO2 availability for exploitation. The tota l EOR prize is believ ed to total or exceed 100 billion barrels of oil, including existing commercial oil reservoirs and new residual oil zones.

For comparative purposes, ANWR represents approximately 10.4 billion barrels of technically recoverable oil, with an es timated production pot ential of about 1.4 million barrels per day. In contrast, U.S. CO2 EOR offers the potential to add almost three times the daily production of ANWR, and 10+ times the oil reserves, while at the same time creating very large markets and ge ologic sequestration "sinks" for billions of tons of CO2.The graphic below (Figure 2) is a simplified diagram of the CO2 EOR process. In commercial operations carbon dioxide is transported under pressure to the
p roject area by pipeline in what the industry refers to as the CO2 dense phase. The compressed CO2 is then sent underground into a targeted underground oil "pay zone" through injector wells where it acts as a solvent reducing the oil viscosity and surface tension, thus freei ng the oil to be "swept" to production wells. A CO2 injection well is typi cally surrounded by a number of production wells organized in a "pattern". Any CO2 produced with the oil is separated and reinjected. The CO2 that is not recycled is effectively trapped within the formation in dead-end pores and channels. When the EOR project is complete all wells are plugged with cement and th e CO2 is permanently sequestered underground.

In current practices, the amount of CO2 in jected to mobilize oil is carefully controlled due to the cost of the CO2. Th e yield of a CO2 EOR project typically varies from two to four barrels of oil pr oduced from every ton of CO2 purchased. CO2 EOR has not seen wider application because of the high project capital costs, historically low oil prices, and limited supplies of low cost, pure CO2. But in today’s high oil price environment, the main constraint is a shortage of CO2. Enhanced oil recovery operators are currently paying between $10 and $30
p er ton for CO2, when they can find it. The market is there. The challenge is to
p rovide incentives for more CO2 generators to capture their carbon dioxide streams, and developers to build CO2 pipe lines from CO2 sources to the oil and methane fields that need it. Today’s supplies of CO2 are a combination of naturally occurring deposits tappe d by underground wells and man made ("anthropgenic") sources captured from some natural gas processing, coal gasification, ethanol productio n, and other operations.

Figure 2: Enhanced Oil Recovery Process with CO2 Injection [see PDF Docket ID EPA-HQ-OW-2008-0390-0230]

Other emerging carbon dioxide application/ sequestration technol ogies are also worth mentioning. These include the enhan ced production of natural gas, coalbed methane, and agricultural products (inc luding algae for fuel production) with CO2. These and other technologies promise to create additional markets for CO2 but require more research a nd development efforts to re ach commercial viability. In contrast, CO2 Enhanced Oil Recovery is already commercial and can be quickly expanded.

Rapid expansion of Enhanced Oil Recovery provides an excellent foundation from which to advance American Energy Securi ty, stimulate and grow the economy, and
p rotect the environment. This can a nd should be followed by the rapid development and deployment of other productive uses of CO2, to enhance natural gas, algae growth for biofuels, etc. Conversely, the current focus on the
p assive, costly sequestration of CO2 in deep saline format ions will increase the
p rice of all U.S. energy products and t hus impose a significant burden on our economy and our society.

Commercial sequestration will enable th e next generation of domestic energy
p roduction. CO2 occurs naturally in the s ubsurface and it is no stranger to geologists who attempt to understand fluid migration and subsurfaceaccumulations. The fact that CO2 can be trapped in s ubsurface formations for geologic times is known and accepted; and we will undoubtedly fi nd more of these locations. Oil and gas "traps" are considered by recognized petroleum engineers and geologist to be excellent final re sting place for CO2. These traps have already demonstrated the ability to hold oil and gas safely undergroud for hundreds of millions of years.

Response: EPA recognizes that the oil and gas industry ha s decades of experience injecting CO2 for the
p urpose of EOR. The GS rulemaking builds upon existing experience and knowledge about safe injection practices in EOR and other injection i ndustries, with tailored re quirements that address the unique nature of CO2 injection for GS.

The Agency clarifies that the final GS rule does not require owners or operators to use GS technologies, nor does it impact business as usual for Class II owners or operators that are injecting CO2 to enhance
p roduction of oil or gas. Those owners or operators that choose to transition from enhanced recovery to GS may do so, provided they meet the requirements for Class VI wells. EPA adds that the intent of the GS rule is not to address the depl oyment of GS or the use of CO2 for ER. Rather, the purpose of the GS regulation is to ensure consistenc y in permitting undergr ound injection of CO2 at GS operations across the United States and pr ovide requirements to prev ent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble, including the discussion of the repermitting of Class II EOR wells for GS, as we ll as the rulemaking docket.

Comment: 2. We generally agree with and endorse the Texas Carbon Capture and Storage Association (TxCCSA) comments to the Proposed Rule.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter and TxCCSA’s comment letter for fu rther details. For additional information on EPA's final regulatory approach, please see the final rule and preamble, as well as the rulemaking docket.

Comment: Re: Docket ID No. EPA-HQ -OW-2008-0390 (Proposed Federal Requirements Under the Underground Injection Control Program fo r Carbon Dioxide Geologic Sequestration Wells)

The Oil and Gas Conservation Division of the Oklahoma Corporation Commission regulates oil and gas explor ation and production activiti es and administers the Class II Underground Injection Control (UIC ) program in the State of Oklahoma.

The division has followed th e stakeholder discussions concerning the referenced
p roposal with keen interest, particular ly regarding those portions of the
p roposal that may affect the management and regulation of the states oil and
g as resources. Commenter Name: A. James Ma y e r Letter ID: 0230 Commenter Or g anization: A. J. Mayer International on behalf of the American Ener gy Securit y Initiative Comment ID: 21873

Commenter Name: Lori Wrotenbery Letter ID: 0247 Commenter Or g anization: Oklahoma Corporation Commission Comment ID: 22233Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble, including the discu ssion of the repermitting of Class II EOR wells for GS, as well as the rulemaking docket.

Comment: To Whom Concerns:

On July 25, 2008, the Environmental Protection Agency (EPA) published in the Federal Register, a proposed rule setting forth new requirements under the Safe Drinking Water Act (SDWA) for the underground injection of carbon dioxide (CO2) for the purpose of long-term storage, or geologic sequestration (GS). The regulation is proposed under the authority of the SDWA to ensure protection of underground sources of drinking water from injection related activities. EPA views the capture and inje ction of CO2 produced by hum an activities for longterm storage as one of a portfolio of opt ions that can reduce CO2 emissions into the atmosphere and help mitigate climate change.

WEST Associates (Western Energy Supply a nd Transmission Associates, or "WEST") respectfully submits its comments and recommendations, herein.

WEST Associates is comprised of 16 i nvestor and publicly owned electric utilities serving the rapidly growing 11 western states and North Dakota. In recent years, WEST Associates has worked with other stakeholders to advocate development of environmental laws a nd regulations that are based on sound science and achieve state and national environmental goals in a rational and cost effective manner. WEST Associates’ members own and operate coal and gasfired electric generating facilities and are also i nvolved in the planning and development of additional new el ectric generating facilities.

WEST Associates Policy Comments:

WEST’s comments on this rulemaking address EPA’s proposed Alternative 3 which would create a new class of injection wells (Class VI) and proposes minimum technical criteria for geologic site ch aracterization, fluid movement, area of review (AoR) and corrective action, well construction, operation, mechanical integrity testing, monitori ng, well plugging, post injecti on site-care, and site closure for the purposes of protecting underground sources of drinking water (USDWs). The proposal is based on the existing Underground Injection Control (UIC) regulatory framework, wi th modifications to address the unique nature of CO2 injection for GS. WEST's comments se t forth several policy level concerns and recommendations, followed by some co mments and recommendations concerning the specific aspects of the proposed rulemaking.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble, including sections on site characte rization, AoR, cons truction, operation, testin g and monitorin g , and site closure, as well as the rulemakin g docket. Commenter Name: Kevin Wantta j a Letter ID: 0248 Commenter Or g anization: Western Energy Supply and Transmission Associates Comment ID: 22237Comment: WEST Associates sincerely appreciates this opportunity to comment and provide recommendations on EPA’s proposed rule regarding UIC for CO2 Geological Sequestration.

Should you have any questions or need further information, please do not hesitate to contact David Steele at (520) 321-1111.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Comment: I am writing, on behalf of the multi-sect or membership of the Western Business Roundtable (the "Roundtable"), in respons e to the Environmental Protection Agency’s (the "Agency’s") request for public comments regarding its proposed rulemaking to implement federal requireme nts under the Safe Drinking Water Act ("SDWA") Underground Inject ion Control (UIC) Program for carbon dioxide (CO2) geologic sequestration wells (73 Fede ral Register 43492, August 28, 2008).

The whole issue of CO2 management has tremendous macro-economic, consumerpocketbook, environmental and nationa l security implications. Extensive Congressionaland regulatory reviews are unde rway regarding the efficacy of mandatory carbon regulations. A necessary predicate to any such regime must be a clear understanding of:

“ The effectiveness of sequestration and storage options; “ Hurdles to the efficient impl ementation of those options; “ CO2 transportation system challenges; and “ Liability issues associated with bot h transportation and storage of CO2.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket. EPA clarifies that climate change policy, evaluating th e barriers to CO2 storag e, and CO2 transport are outside the scope of the GS rulemaking. Rather, th e purpose of the GS regulation is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and
p rovide requirements to pr event endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: The Western Business Roundtable is a broad-based coalition of companies doing business inthe Western United States. Our me mbers are engaged in a wide array of enterprises, includin g : manufacturin g ; retail ener gy sales; minin g ; electric Commenter Name: Kevin Wanttaja Letter ID: 0248 Commenter Or g anization: Western Ener gy Suppl y and Transmission Associates Comment ID: 22251

Commenter Name: James T. Sims Letter ID: 0249 Commenter Or g anization: Western Business Roundtable Comment ID: 22253

Commenter Name: James T. Sims Letter ID: 0249 Commenter Or g anization: Western Business Roundtable Comment ID: 22256p ower generation and transmission; energy infrastructure development; and oil and gas exploration, development, transportation and distribution. We work to defend the interests of the West and s upport policies that encourage economic growth and opportunity, freedom of enterprise and a common-sense, balanced approach to conservation and environmental stewardship.

Most of our members are cen trally involved in the development, transportation and processing of a wide variety of ener gy resources -- fossil, renewable and nuclear -- as well as the generation and distribution of electricity across the West and technologies that facilitate greater energy conservation and efficiency. Roundtable members also ar e on the cutting edge of technology development related to the ma nagement of CO2 emissions.

I hope you will find the broad perspectiv e and expertise reflected in this letter helpful as the Agency moves fo rward with its deliberations on this important policy issue.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble, as well as the rulemaking docket.

Comment: CONCLUSION

On behalf of the many member organizati ons of the Western Business Roundtable, thank you for the opportunity to provide our input on this crucially important
p ublic policy issue, the implications of which are so pivotal to the continued vitality of the West.

Response: EPA acknowledges the comment. Pl ease see the remainder of EPA' s responses to this letter for further details.

Comment: We therefore are pleased to submit these comments on EPA’s proposed rules concerning "Federal Require ments Under the Underground Injection Control (UIC) Program for Carbon Dioxide (CO2) Geologi c Sequestration (GS) Wells, 73 Fed. Reg.43492 (July 28, 2008).

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: F. Conclusion Commenter Name: James T. Sims Letter ID: 0249 Commenter Or g anization: Western Business Roundtable Comment ID: 22268

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22276

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22328Our Environmental NGO Group appreciates th e opportunity to provide comments to EPA on this most important rulemaking effort. A final rule will represent a significant step forward in combating gl obal climate change, and the time is more than ripe for the U.S. to take such steps. When EPA issues its final rule, we feel it must be both technically s ound and adaptive to reflect learning from experience with GS projects in as seamless a manner as is possible. We very much look forward to continuing to work with the Agency on this rule, as well as other efforts under the Agency’s existing authority to address the significant
p roblem of climate change in the near term.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Comment: Comments of: Clean Air Task Force Clean Water Action Environmental Defense Fund N atural Resources Defense Council Western Resource Advocates

A. Introduction

The Clean Air Task Force, Clean Water Action, Environmental Defense Fund, N atural Resources Defense Council, and Wes tern Resource Advocates (Environmental N GO Group) thank EPA for the opportunity to comment on the Proposed Rule on carbon dioxide sequestration wells under the Underground Injection Control (UIC) Program.

Founded in 1996, the Clean Air Task Force (CATF) is a nonprofit organization dedicated to restoring clean air and he althy environments through scientific research, public education, and legal advocacy.

Founded in 1972, Clean Water Action (CWA) ha s 1.2 million members and offices in 20 states. Clean Water Action works to improve public he alth and environmental
p rotection through grassroots organizi ng, policy research and advocacy.

Environmental Defense Fund (EDF), founde d in 1967, is a non-profit organization that represents more than 500,000 members. EDF links science, economics and law to create innovative, equita ble and cost-effective solu tions to society’s most urgent environmental problems.

The Natural Resources Defense Council (NRDC) is a national, nonprofit organization of scientists, lawyers and environmental specialists dedicated to
p rotecting public health and the envir onment. Founded in 1970, NRDC has more than 1.2 million members and online activists nationwide, served from offices in N ew York, Washington D.C., San Francisc o, Los Angeles, Chicago and Beijing. Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 24726Western Resource Advocates (WRA) is a regional non-profit organization using law, economics and policy an alysis to protect the land, air and water of the Interior Western United States.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter as well as the comments of EDF, and NRDC for further details. For additional information on EPA's final regulatory approach, please see the final ru le and preamble as well as the rulemaking docket.

Comment: General Comments

While CCGS is only one technology in a portf olio of many that wi ll need to be implemented to achieve carbon emissions st abilization, it is most amenable tomitigating the emissions from large stationary CO2 sources, particularly carbonbased fossil fuel power plants which acc ount for nearly 80% of the cumulative total CO2 emissions from large stationa ry sources (IPCC, 2005). Furthermore, CCGS has been identified as the crit ical enabling technology for reducing CO2 emissions significantly while allowing the use of carbon-based fossil fuels, especially coal, to meet the world's en ergy demands (The Future of Coal, 2007). Meeting carbon emissions stabilization goals will be more easily achieved if mitigative measures are impl emented sooner rather than later. Therefore, while the enabling CCGS legal and regulatory framework must pr ovide for the protection of ground water and other natural resources, it must not contain elements that would hinder the timely deployment of commercial scale CCGS projects.

Response: EPA acknowledges the comment. EPA agrees that GS is one technology in a portfolio of options, including solar, wind, biomass, and geot hermal, that could be deployed to reduce CO2 emissions; however these technologi es are outside the scope of the UIC GS rulemaking. EPA clarifies that the GS regulation does not promote or encourage the use of GS; rather it is designed to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and
p rovide requirements to pr event endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA clarifie s that mitigating climate change is outside the scope of the GS rulemaking. Please see the remainder of EPA's respons es to this comment for further details. For additional information on EPA's final regulatory approac h, please see the final rule and preamble as well as the rulemaking docket.

Comment: Specific Comments on Topics

In the preamble to the proposed rule, EPA asked for comments on approximately 50 topics. Following are our commen ts on some of those topics.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemakin g docket. Commenter Name: Walter L. Bake r Letter ID: 0253 Commenter Or g anization: Utah Division of Water Qualit y Comment ID: 22337

Commenter Name: Walter L. Bake r Letter ID: 0253 Commenter Or g anization: Utah Division of Water Quality Comment ID: 22340Comment: References Cited Federal Ac tions Will Greatly Affect the Viability of Carbon Capture and Storage As a Key Mitigation Option, Report to the Chairman of the Select Committee on Energy Independe nce and Global Warming, House of Representatives, U.S. Government Accountability Office (GAO), September, 2008.

IPCC, 2005: IPCC Special Report on Carbon Di oxide Capture and Storage. Prepared by Working Group III of the Intergovernmental Panel on Climate Change [Metz, B., O.Davidson, H.C. de Coninck, M. Loos, and L.A. Meyer (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 442 pp.

The Future of Coal: Options for a Carbon- Constrained World, An Interdisciplinary MIT Study, 2007

IOGCC. 2007. Storage of Carbon Dioxide in Geologic Structures; A Legal and Regulatory Guide for States and Provinces . Prepared by the Interstate Oil and Gas Compact Commission. September 25, 2007.

The Liability of Carbon Dioxide Storage, Mark Anthony de Figueiredo, MIT Ph.D Thesis, February 2007.

Response: PA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: Discussion

Our remarks focus on the following areas: (1) location of CO2 injection (a.k.a. "Siting"); (2) liability unde r RCRA and CERCLA; (3) pos t closure care; and (4) dual purpose wells and grandfathering of certain Class II wells.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory approach (including site characterization, post-injection si te care, and the repermitting of Cl ass II/EOR wells for GS), please see the final rule and preamble as well as the rulemaking docket.

Comment: Conclusion

The Foundation appreciates EPA's initiati ve to commence this rulemaking to
p rovide regulatory clarity for GS of CO2 and welcomes this and future opportunities to provide input on the pro j ect. We respectfull y request that EPA Commenter Name: Walter L. Bake r Letter ID: 0253 Commenter Or g anization: Utah Division of Water Qualit y Comment ID: 22357

Commenter Name: Mike Nasi Letter ID: 0254 Commenter Or g anization: Clean Coal Technolo gy Foundation of Texas Comment ID: 22361

Commenter Name: Mike Nasi Letter ID: 0254 Commenter Or g anization: Clean Coal Technolo gy Foundation of Texas Comment ID: 22368carefully consider the comments set out a bove as the final rule and preamble are
p repared.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: Introduction & Background

The Clean Coal Technology Foundation of Texas ("CCTF" or "Foundation") appreciates the opportunity to submit comments to the U.S. Environmental Protection Agency ("EPA") regarding th e proposed Federal requirements for underground injection of carbon dioxide ("CO2") for the purpose of geologic sequestration ("GS"). The Foundation wa s founded in January, 2004, as a nonp rofit entity to support the mission of the Governor's Clean Coal Technology Council (Council). The Foundation exists to promote the use and development of clean coal technologies th at will result in re liable, low cost, and environmentally responsible energy for Texas.

The Foundation views the regulatory framework that will govern CO 2 GS as one of the key bridges on the road to widesp read carbon capture because project developers will not be willing to ta ke the financial and technology risk associated with CO2 capture if they do not see a storage option that is free of regulatory pitfalls. The regulatory regime governing CO2 GS could stand in the way of widespread carbon capture if it is perceived as confusing, too bureaucratic, or structured in a way that creates undue risk of statutory environmental liability. The comments that follow are focused on the aspects of the proposed rules that the Foundation beli eves could impair our efforts to speed the commercialization of carbon capture technology.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

EPA clarifies that the intent of the GS rule is not to promote or encourage the use of GS; rather, its
p urpose is to ensure consistency in permitting underground injection of CO2 at GS operati ons across the United States and provide require ments to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Other EPA Comment Codes and Descriptions: 1200 1.1 General comments about the rulemaking Comment: In conclusion, ExxonMobil is committed to working with the EPA individually and through the API and other groups to develop scientifically sound,
p erformance based regulations for the geologic storage of C02. E ach of the areas of concern we have identified are more fully addressed in API's comments. Commenter Name: Mike Nasi Letter ID: 0254 Commenter Or g anization: Clean Coal Technolo gy Foundation of Texas Comment ID: 24728

Commenter Name: Ken Mille r Letter ID: 0257 Commenter Or g anization: ExxonMobil Production Compan y Comment ID: 22371Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment and API’s comment for further details. Fo r additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Comment: To Whom It May Concern:

ExxonMobil Production Company (a Division of ExxonMobil Corporation) appreciates the opportunity to submit comments on the Environmental Protection Agency's (EPA)
p roposed rules for Geologic Storage of Carbon Dioxide (GS) under the Safe Drinking Water Act (SDWA) Underground Injection Control Program. Exxon Mobil Corporation is a fully integrated oil and gas company with world-wide operations. Exxon Mobil Corporation has significant experience in operations directly related to geologic storage such as carbon dioxide (CO2) based enhanced oil recovery (EOR), separation of CO2 from natural gas streams, acid gas injection, geologic imaging and modeling, injection well inte grity management, as well as an industry leading research and devel opment program which includes carbon management technologies.

ExxonMobil would like to compliment the EPA on the open and transparent process they have followed in deve loping these draft rules.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: The NAM appreciates the opportunity to co mment on this proposal. Manufacturers look forward to working with federal officials to craft a comprehensive framework that will promote the commer cial viability of CCS. For more information related to the NAM’s posit ion on CCS technology, please contact Bryan Brendle at (202) 637-3176.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

EPA clarifies that the intent of the GS rule is not to promote or encourage the use of GS; rather, its
p urpose is to ensure consistency in permitting underground injection of CO2 at GS operati ons across the United States and provide require ments to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: Rule Provision: Part 144 Commenter Name: Ken Mille r Letter ID: 0257 Commenter Or g anization: ExxonMobil Production Company Comment ID: 24729

Commenter Name: Keith McCo y Letter ID: 0258 Commenter Or g anization: National Associati on of Manufacturers Comment ID: 22376

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24831EPA Proposal:1. The authority citation for part 144 continues to read as follows:

Authority: 42 U.S.C. 300f et seq.; Res ource Conservation and Recovery Act, 42 U.S.C. 6901 et seq.

GWPC Recommendations: No comment necessary

Response: EPA acknowledges the comm ent. The final rule retains this text.

Comment: The IPCC's 2005 report on "Carbon Capture and Storage" notes that mature sedimentary basins such as the Willist on Basin in the upper Great Plains are "prime targets for CO2 storage because: (1) they have well-known characteristics; (2) hydrocarbon pools and/or coal beds have been discovered and
p roduced; (3) some petroleum reservoirs might be already depleted, nearing depletion or abandoned as uneconomic without advanced production systems such as EOR: (4) the infrastructure needed for CO2 transport and injecti on may already be in place." [FN1] Use of CO2 for EOR often a dds an additional 7-23% of incremental oil recovery from a field, and depleted oi l fields have advantages for CO2 sequestration because "the oil and gas th at originally accumulated in traps (structural and stratigraphi c) did not escape (in some cases for many millions of years), demonstrating their integr ity and safety," and because "the geological structure and physical propertie s of most oil and gas fields have been extensively studied a nd characterized." [FN2] IPCC 's 2005 "Carbon Capture and Storage" Report also recognizes that Basin Electric's DGC/Weyburn project, "despite the presence of many hundreds of existing wells, after four years of CO2 injection there has been no measurab le leakage (Strutt et al., 2003)."[FN3] Thus, EOR is an established option for CO 2 sequestration in the Williston Basin, and geological formations are holding sequestered CO2 without leakage. There is an identified need for additional CO2 fo r EOR in the Williston Basin when the technology becomes mature enough to provi de it at a reasonable cost to customers. Basin Electric's AVS Post-Combustion CO2 Captur e Project is an attempt to move that technology forward.

In addition to EOR options, saline aqui fers have been identified in the Mississippian Madison geologi cal formation of the Will iston Basin with the capacity to store approximately 60 gigat ons (i.e., 60 bill ion tons) of CO2, which is enough capacity, for example, to store all of the CO2 emitted from a facility emitting 3 mil lion tons of CO2 per year for 20,000 years.

IPCC's 2005 report on "Carbon Capture and Storag e" also says that most scenarios
p roject that the supply of primary energy us ed by humans will continue to be dominated by fossil fuels until the middl e of the 21st-century.[FN4] The IPCC notes that stabilizing CO2 le vels in the atmosphere will not likely be achieved with a single technological option, but CO2 capture and storage (CCS) in geological formations is one of the most important technologies that may make such stabilization possible" [FN5] Commenter Name: Claire Olson Letter ID: 0260 Commenter Or g anization: Basin Electric Power Cooperative Comment ID: 22384"[T]he global capacity to store CO2 deep underground is large. Depleted oil and gas reservoirs are estimated to have a storage capacity of 675-900 [metric gigatons of] CO2. Deep sali ne formations are very likely to have a storage capacity of at least 1000 [metric gigatons of] CO2 and some studies suggest it may be an order of magnitude greater th an this, but quantific ation of the upper range is difficult until additiona l studies are undertaken."[FN6]

The IPCC "Carbon Capture and Storage" Report acknowledges that natural underground accumulation of CO2 is "a wi despread geological phenomenon," and that '[w]hile there are differences betw een natural accumulations and engineered storage, injecting CO2 into deep geologi cal formations at carefully selected sites can store it underground for long periods of time: it is considered likely that 99% or more of the injected CO2 will be retained fo r 1000 years."[FN7]

Response: EPA acknowledges the comment. EP A reviewed the IPCC report, as well as more recent information on GS a nd Carbon Capture and Storage while devel oping the final GS rule. Please see the remainder of EPA's responses to this letter for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: IV. Comments on Identified Issues

The following comments are directed to th e specific questions raised in the
p roposed rule.

Response: EPA acknowledges the comment. Pl ease see the remainder of EPA' s responses to this letter for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: In an effort to reduce possible duplicat e comments, we have reviewed the comments prepared by industry groups to wh ich we belong and agree generally with the conclusions and approach of those co mments. Those groups are as follows :

Carbon Capture and Storage Alliance FutureGen Industrial Alliance Coal Utilization Research Council Gasification Technologies Council N orth American Caron Captur e and Storage Association Western Business Roundtable

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter and res ponse to comments from the Carbon Capt ure and Storage Alliance, FutureGen Industrial Alliance, Coal Utilization Research Council, Gasification Technologies Council, North American Carbon Capture and Stor age Association, and Western Bu siness Roundtable for further details. For additional information on EPA's final regulatory approach, please see the final rule and
p reamble as well as the rulemakin g docket. Commenter Name: Claire Olson Letter ID: 0260 Commenter Or g anization: Basin Electric Power Cooperative Comment ID: 22387

Commenter Name: Dianna Tickne r Letter ID: 0262 Commenter Or g anization: Peabod y Ener gy Comment ID: 22994Comment: Metropolitan appreciates this opportunity to provide comment and asks that EPA carefully consider these comments as well as those by AWWA and other drinking water concerns. Please contact me at (213) 217-5696 if you have any questions,

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter and AWWA’s comment for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: Fasken Oil and Ranch, Ltd. has reviewed the Western Business Roundtable's comments concerning these proposed re gulations and fully supports their comments. Any questions concerning our comm ents can be directed to me at the

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment and Western Business Roundtable’s comment fo r further details. For additional information on EPA's final regulatory approa ch, please see the final rule and preambl e as well as the rulemaking docket.

Comment: [FN:1] The recommendations presented in this letter reflect a consensus among the signatories on the specific issues addressed; however, some of the signatories note that their participati on should not be interpreted as an express or implied change in views on othe r issues that may be related to the issues addressed. In particul ar, CATF, EDF and NRDC rese rve the respective views they have expressed regarding the appropr iate legal authority for the rule, the definition of geologic sequestration, and necessary requirements needed if injection is to be allowed above the lowermost underground source of drinking water (see comments to EPA dated Decem ber 24, 2008 and letters dated March 17, 2009).

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter and responses to comments from CATF, EDF, and NRDC for further details. For additional information on EPA's final regulatory approac h, please see the final rule and preamble as well as the rulemaking docket.

Comment: The organizations identified below reque st that the Environmental Protection Agency (EPA) extend from November 24, 2008 to December 19,2008 the public comment period on the proposed rule for geologic sequestration of carbon dioxide under the Safe Drinking Water Act (SDWA) . "Federal Requirements Under the Underground Injection Control (UIC) Progr am for Carbon Dioxide (C02) Geologic Sequestration (GS) Wells", 73 Fed. Re g . 43491-541 Jul y 25, 2008). The Commenter Name: Mic Stewart Letter ID: 0279 Commenter Or g anization: Metropolitan Water District of Southern California Comment ID: 24096

Commenter Name: Jimm y Carlile Letter ID: 0281 Commenter Or g anization: Fasken Oil & Ranch Comment ID: 24115

Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25305

Commenter Name: K y le Isakowe r Letter ID: 0298 Commenter Or g anization: American Petroleum Institute Comment ID: 29317organizations supporting this request repr esent a broad array of interests in the issues associated with this rulemaki ng and many of us have been discussing these interests and issues in an effort to reach consensus or at least narrow our differences. We request this extension so we can continue efforts toward submission of recommendations reflecting common views on a number of the major issues in this rulemaking on which EPA expressly requested comment and several other issues that have arisen during our dialogue on this rulemaking.

Initially facilitated by EPA's technical workshops to develop understanding and helpful public meetings to discuss EPA' s rulemaking approach, our discussions have been enhanced by th e efforts of the Ground Water Protection Council, the Interstate Oil and Gas Compact Commission and the World Resources Institute, in which many of our organizations have pa rticipated. They have been further informed by the ongoing research efforts of the Regional Carbon Sequestration Partnerships under the support of the Depart ment of Energy and a number of other research activities and me etings conducted by academic and other institutions actively involved in technical research and information exchanges on the issues underlying this rulemaking, in which re presentatives or members of our organizations have partic ipated. As a result of EP A's proposal, dialogue on these issues has expanded, become more focused and achieved substantial progress in reaching agreement on a number of issues that should better inform EPA's development of its final rule.

We have already agreed that EPA's propos al provides a solid foundation on which to develop the regulatory framework for geologic sequestration on issues within the purview of the SDWA and that developm ent of this rule should proceed with EPA's proposal as the starting point. The issues on which we believe additional time would be helpful to development of common views or understanding include:

- The establishment of inje ction pressure limitations for geologic sequestration injection wells;

- How various types of target formations should be addressed wi thin the underground injection control (UIC) pr ogram, including requirements for geologic sequestration in oil and gas reservoirs;

- The process and criteria for achieving cl osure of geologic seque stration projects;

- Consideration of current and potential future source waters in areas with constrained water resources; and

- Addressing issues relating to public wa ter systems in proximity to geologic sequestration projects.

We believe that the request ed limited extension of the public comment period will allow time for continuation of dilige nt efforts to reach consolidation of shared understanding on these issues and possibly submission of recommendations reflecting that understanding and significant agreement on how these issues can be addressed and resolved. The undersigned submit this request on behalf of the listed organizations that have author ized submission of their names as supporters of this request.Response: Robert F. Van Voorhees Partner, Environmental Group Bryan Cave LLP 700 Thirteenth Street, N.W. Suite 700 Washington, D.C. 20005-3960

Dear Mr. Van Voorhees:

Thank you for your letter of Nove mber 17,2008 to Stephen L. Johnson, Administrator of the U.S. Environmental Protection Agency (EPA), transmitting a request from multiple organizations seeki ng an extension on EPA's proposed rule for geologic sequestration under the Safe Drinking Water Act (S DWA). I have been asked to respond to your letter.

In response to your request, Assistan t Administrator Benjamin Grumbles extended the comment period for the notice through December 24,2008. This was announced in a Federal Register notice on November 21,2008.

We are pleased to see that the signatory organizations to the letter are working together to understand each other's perspect ive and work through issues of concern. We hope that the additional time afforded by the ex tension will result in comments that will help the Agency develop a rule that will al low the technology to move forward while also ensuring protection of underground sources of dr inking water.

Thank you again for your letter. Please shar e this information with the supporters of the request. If you have any questions, please contact me or Steve Heare, Director of the Drinking Water Protection Divisi on, at 202-564-3751.

Sincerely,

Cynthia C. Dougherty, Director Office of Ground Water and Drinking Water

Comment Code: 1200 1.1 General comments about the rulemaking



### Individual Comments

Comment: The EPA’s proposed rule to regulate CO2 injection pursuant to the Safe Drinking Water Act is well researched and thorough, and contains important technical review and information for the effectiv e storage and regulation of storage facilities for CO2 streams. This rule making will thus provide important

re g ulator y consistenc y for CO2 capture, in j ection, and stora g e, which will in Commenter Name: Victor B. Flatt Letter ID: 0103 Commenter Or g anization: The Center of Environment, Energy & Natural Resources Law (EENR Center), Universit y of Houston Law Cente r Comment ID: 22489turn facilitate further and more effici ent deployment of CCS technologies and
p rojects.

Response: EPA acknowledges the comment. The purpose of the rule is to ensure consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. Please see the remai nder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory approac h, please see the final rule and preamble as well as the rulemaking docket.

Comment: CIBO notes generally that the proposed rule raises many questions for facilities that are potentially regulated under this rule. In f act, it is unclear from the
p roposal what facilities may be regulated directly and even more unclear what facilities may ultimately shoulder some liability for the obligations outlined in the proposal. Th roughout the proposal EPA iden tifies significant areas

Response: EPA clarifies that the GS rule applies to owners or operators of wells that will be used to inject CO2 into the subsurface fo r the purpose of long-term storage.

Please see the remainder of EPA' s responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final ru le and preamble as well as the rulemaking docket.

Comment: - Page 43497 under what are the "Potential US DW Impacts." Please consider adding at the very end of this section a senten ce that reaffirms for the reader that the fundamental purpose of the proposed Class VI rule is to make sure that the bad things above enumerated do not occur.

- Page 43502, third sentence under "How W ould this Proposal Affect Existing Injection Wells Under the UIC Program?" Pl ease consider being specific as to what kind of "production" is being discus sed here. From the context of this sentence it would seem to be "production of oil" or perhaps "production of hydrocarbons" but it would not seem to cover "production of brackish waters for the purpose of desalination to provide potable water." The phrase "any
p roduction seems overly vauge.

- Page 43505 within the discussion of CO 2 storage in coal seams. It is incorrect to state that "the process of CO2 adsorption to the coal has not been
p roven." This is well established. I th ink what USEPA intended to say was something like "the commercial applicat ion of coal-based CO2 storage has not been proven." The fundamental principle of CO2 adsorbing on the coal surface is established. Whether this is going to work in situ and at commercial scale has not been established / proven. Please consider rewording. Commenter Name: Robert Bessette Letter ID: 0139 Commenter Or g anization: Council of Industrial Boiler Owners (CIBO) Comment ID: 23079

Commenter Name: James Doole y Letter ID: 0156 Commenter Or g anization: Joint Global Change Research Institute, Pacific N orthwest National Laborator y Comment ID: 22674- Page 43516. "Simulations discussed in th e manual confirm seismic and - What - manual"? It is not clear what is being discussed here.

Response: In response to the comment regarding production, EP A clarifies that this discussion refers to Class II wells, which are associated with the recovery of oil and or gas. The purpose of the discussion is to distinguish injection (which is regulated under the UIC regulat ions) from production (which is not).

In response to the comment regardi ng CO2 adsorption to the coal, EPA cl arifies that GS in unmineable coal seams has been the subject of less research than saline formations or deplet ed oil and ga s reservoirs. EPA acknowledges that site-suitabi lity for GS is dependent on a number of factors and that many formation types may be suitable for GS. The final GS rule does not preclude injection into unmineable coal seams (or any formation type) provided owners or operators can demonstrate that GS can be
p erformed in a manner that protects USDWs from e ndangerment. The Agency anticipates that in the near-term, most GS in unmineable co al seams will continue to be e xperimental. Such projects may be
p ermitted as Class V experimental technology wells if they are of an experimental nature (i.e., to test GS technologies and collect data).

The "manual" referenced on page 43516 is the GE O-SEQ Best Practices Manual. Geologic Carbon Dioxide Sequestration: Site Evaluation to Impl ementation. Lawrence Berkel ey National Laboratory. Paper LBNL-56623. The GEO-SEQ Best Pr actices Manual is available at: http://www.netl.doe.gov/technol ogies/carbon_seq/refshelf/GE O-SEQ_BestPract_Rev1-1.pdf.

Please see the remainder of EPA' s responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final ru le and preamble as well as the rulemaking docket.

Comment: Concern #12: EPA's schedule for promulgation of its proposed UIC regulation (Page 43499 Sec. E3)

We reference the following statement from the preamble section of the proposed rule : "During the Deployment Phase (2008- 2017), the [RCSP] partnerships will conduct large volume carbon storage tests to demonstrate that large-scale CO2 injection and storage can be achieved safe ly and economically. EPA will use the data collected from these projects to s upport decisions in the final GS rule." This statement suggests that a final GS rule may not be issued until 2017. We believe that this is too late to clear the regulatory uncertainty that CCS
p roject developers are facing today. If this reflects EPA's intention, we recommend that EPA abandon a prescriptive approach and instead, favor general and performance- based requirements unt il these demonstration tests are completed.

Response: EPA believes that sufficient data have been collected to inform the final GS rule. N evertheless, EPA anticipates that fu ture experimental and full-scale projects will continue to inform the technology, and is therefore using an adaptive rulemaking approach. EPA plans, every six years, to collect and review data on GS projects to determ ine whether the appropria te amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary. Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technolo g ies Council (GTC) Comment ID: 23767Other EPA Comment Codes and Descriptions: 5400 2.9 Proposed Financial Responsibility and Long-Term Care Requirements Comment: SUMMARY

San Miguel applauds the efforts EPA has ta ken thus far to instill "certainty" and "transparency" into the future Clas s VI CO2 regulatory regime, 73 Fed. Reg. at 43496. The challenge EPA faces is to cr aft a Final Rule for commercial CO2 injection appropriate for activities that will largely be conducted in the future. EPA has had to confront many t echnical uncertainties regarding the establishment and operation of GS wells. Because many of the technical aspects are unknown, it is also very difficult to develop a clear understanding of
p roject risks and liabilitie s. As long as risks and liabilities are largely unknown and open-ended, private companies will not step fo rward to offer insurance and other risk management pr oducts, and it will not be possible to obtain the level of financing needed to undertake a costly GS operation. We hope the pilot carbon capture and sequestration (CCS) projects conducted by DOE and other entities will help resolv e some of these uncertainties.

Response: To address concerns about certainty, EPA has specified acceptable financial responsibility instruments and requirements in the final re gulation at §146.85. Additiona lly, EPA is developing guidance (available on EPA's website at http://water.epa.gov/type/groundwater/u ic/wells_sequestration.cfm) that describes the types of financial instruments that owners or operators can use to meet financial responsibility re quirements for GS wells.

EPA adds that it anticipates that, as GS is deployed, particularly if there are early successful uses of these financial instruments, owners or operators will demand and car riers will offer third-party GS financial instruments in greater num bers. See the final rule and preambl e for further discussion of EPA's final approach to financial responsibility.

Other EPA Comment Codes and Descriptions: 5400 2.9 Proposed Financial Responsibility and Long-Term Care Requirements Comment: SUMMARY

N RECA applauds the efforts EPA has taken thus far to instil l "certainty" and "transparency" into the future Class VI CO2 regulatory regime. 73 Fed. Reg. at 43496. The obvious challenge confronting EP A is to craft a Final Rule for commercial CO2 injection activities when large-scale commercial operations are only at the nascent stage. In the pr ocess of developing regulations for activities that will largely be conducted in the future, EPA has had to confront many technical uncertainties regarding th e establishment and operation of GS wells. Because many of the technical aspects are unknown, it is also very difficult to develop a clear understanding of project risks and liabilities. As long as risks and liabilities are la rgely unknown and open-ended, private companies will not step forward to offe r insurance and other risk management
p roducts, and it will not be possible to obtain the level of financin g needed to Commenter Name: Joseph Eutizi Letter ID: 0161 Commenter Or g anization: San Mi g uel Electric Cooperative, Inc Comment ID: 21283

Commenter Name: James Stine Letter ID: 0163 Commenter Or g anization: National Rural Electric Cooperative Association (NRECA) Comment ID: 21311undertake a costly GS operation.

Response: To address concerns about certainty, EPA has specified acceptable financial responsibility instruments and requirements in the final re gulation at §146.85. Additiona lly, EPA is developing guidance (available on EPA's website at http://water.epa.gov/type/groundwater/u ic/wells_sequestration.cfm) that describes the types of financial instruments that owners or operators can use to meet financial responsibility re quirements for GS wells.

EPA anticipates that the availability of third-party GS financial inst ruments will grow in response to demand for such instruments by GS well owners or operators as deployment of GS technology increases in the future. In addition, EPA plans to allow owners or operators to choose from a variety of financial instruments to meet their financial responsibility needs, thereby allowi ng owners or operators flexibility. See the final rule and preamble for further discussion of EPA's final approach to financial responsibility. EPA is using an adaptive approach to regulating GS.

Comment: 4. APPA strongly encourages the EPA to re cognize the inextricable link between energy and water use. Water demand for pow er production remains intense, and may grow concurrently with demand growth a nd population growth. APPA recommends the Desalination and Water Purification Technology Roadmap developed by Sandia N ational Labs in 2003 as a summary of the wate r -energy issues. [FN2]

[FN2] This document can be downloaded at http://www.sandia.gov/water/de sal/docs/DesalRdmap04a.pdf

Response: EPA clarifies that the linkage of water and energy issues is outside the scope of the GS rulemaking; the purpose of the GS regulation is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in antici pation of the eventual use of GS to reduce CO2 emissions.

Other EPA Comment Codes and Descriptions: 1435 1.2.1.3 EPA should develop guidance Comment: EPA asked for comments on financial guidance on any aspect of the final rule (for example, clarification of requirements for financia l assurance mechanisms). APPA thinks that this might be an ar ea where the EPA might call for a "second bite at the apple" after we know more from the preliminary carbon sequestration
p rojects and "scaling up" projects. We agree with Utility Solid Waste Activities Group (USWAG) and others who have suggested that that guidance must be developed in accordance with OMB’s Good Guidance Pr actices Bulletin, which directs that notice and comment be provided for the development of "significant" and "economically significant" guidance documents.

Response: The GS rule contains minimum technical criteria for the perm itting, geologic site characterization, AoR and corrective action, well construction, operation, mechanical integrity testing, monitoring, financial responsibility, in jection well plugging, post-injection site care, and site closure of GS wells, which will ensure that US DWs are protected from endangerment. Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23376

Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23395To promote consistency while providing the Director with an appropriate level of discretion, EPA is developing guidances for states and tribes that de scribe the process of a pplying for and receiving
p rimacy for GS Class VI wells under Section 1422 of SD WA, as well as the tec hnical and administrative issues associated with developing GS regulations that are the equivalent of minimum federal criteria and requirements. These are available on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

EPA intends to take OMB’s Good Guidance Manual into consideration as financial responsibility guidance is developed. OMB’s Good Guidance Manua l establishes policies a nd procedures for the development, issuance, and use of significant gui dance documents by Executive Branch departments and agencies.

EPA agrees that an adaptive and flexible ap proach is appropriate. To protect USDWs from endangerment and meet the potentially fast pace of GS deployment, EPA is using an adaptive approach to regulating CO2 inje ction for GS. The Agency plans to, every si x years, collect and review data on GS
p rojects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary. An adaptive approach will allow regul atory development to procee d in time to meet the current and future demands for Class VI permits while EPA continues to gather data from pilot projects and other research as it becomes available.

Comment: API commends EPA on their effort in drafting rules for the long-term storage of carbon dioxide. API is very supportive of the fact that EPA has recognized the integrity of the existing re gulatory framework for CO2-ba sed enhanced oil and gas recovery, of EPA's recognition that st orage may occur during activities conducted under a Class II pe rmit without requiring the well to obtain a Class VI permit, of the amount of flexibility operators have in meeting the requirement s in most parts of the proposed rule, and of the use of performance-based st andards aimed at protecting underground sources of drinking water (USDWs).

API also appreciated EPA ex tending the comment period. Du ring that time, API has

Response: EPA acknowledges the comment. EPA recognizes that the oil and gas industry has decades of experience injecting CO2 for the purpose of EOR. The GS rulemaking builds upon existing experience and knowledge about safe injection practices in EOR and ot her injection industries, with tailored requirements that address the unique nature of CO2 injection for GS . Please see the remainder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final rule and pr eamble, including the discu ssion of the repermitting of Class II EOR wells for GS, as well as the rulemaking docket.

Comment: GRE applauds the efforts EPA has taken thus far to instill "certainty" and "transparency" into the future Class VI CO2 regulatory regime, 73 Fed. Reg. at 43496. The challenge EPA faces is to craf t a Final Rule for commercial CO2 in

j ection appropriate for activities that will lar g el y be conducted in the Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24117

Commenter Name: Erik Silvola Letter ID: 0171 Commenter Or g anization: Great River Ener gy Comment ID: 23439future. EPA has had to confront many technical uncertainties regarding the establishment and operation of GS wells. Because many of the technical aspects are unknown, it is also very difficult to develop a clear understanding of
p roject risks and liabilitie s. As long as risks and liabilities are largely unknown and open-ended, private companies will not step fo rward to offer insurance and other risk management pr oducts, and it will not be possible to obtain the level of financing needed to undertake a costly GS operation. We hope the pilot carbon capture and sequestration (CCS) projects conducted by DOE and other entities will help resolv e some of these uncertainties.

EPA needs to establish clear, reasonable regulations that ar e environmentally
p rotective and cover a range of operations for which the technology will not be commercially deployed for a number of y ears. To the extent practicable, EPA needs to establish a single, clear, reas onable and protective liability regime for an activity where the nature of th e risks are different from many other industrial activities and the full extent of possible risks from full scale CSS operations are presently unknown.

Response: EPA agrees that flexibility is important for GS projects. The GS ru le requires owners or operators to submit, and Director s to consider, extensive site-sp ecific data, specified at §146.82, to demonstrate that a site is suitable for GS. Additionally, many of the permit requirements for GS wells are established through individuali zed site-specific plans for AoR a nd corrective action, testing and monitoring, and injection well plugging and post-injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Director discretion. The Agency believes this bala nce allows for GS projects to be designed and
p ermitted to address the unique, si te-specific aspects of each proj ect, while providing consistency in
p ermitting across the U.S.

Please see the remainder of EPA' s responses to this comment for further details. For additional information on EPA's final regulatory approach, including the adaptive rulemaking approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: • While directorial discreti on is a useful mechanism to ensure flexibility in the Final Rule, such discretion must be clearly defined and limited.

Response: To promote consistency while pr oviding the Director with an appropriate level of discretion, EPA is developing guidances for States, Tribes, and Te rritories that describe th e process of applying for and receiving primacy for GS Cla ss VI wells under Section 1422 of SDWA. EPA is also developing guidance on the technical and administrative issues associated with de veloping GS regulations that are the equivalent of minimum federal criteria and requirements. This gui dance will be available on EPA’s website at http://water.epa.gov/type /groundwater/uic/wells_sequestrati on.cfm. Please see the remainder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: With that bein g said, this rulemakin g can resolve some important polic y and Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utilit y Solid Waste Activities Group (USWAG) Comment ID: 23467

Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utility Solid Waste Ac tivities Group (USWAG) Comment ID: 23472legal issues and, in doing so, help fo ster the development of a practical, commercially deployable CCS regulatory progr am. For example, the Final Rule can
p rovide much needed clarity regarding (1 ) the potential for liability under RCRA and CERCLA resulting from CO2 injection and GS activities, and (2) the options for addressing long-term liability fo r Class VI wells. GAO Report at 39-42. As discussed below, there are practical regulatory and legislative options available to resolve these uncertainties that will help assure the
p ublic and the regulated community that CO 2 UIC activities can be conducted in a manner that is both safe and effective.

Response: Please see the remainder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble, including the discussions of RCRA/CERCLA and long-term liability, as well as the rulemaking docket.

Comment: Promotion of CCS

The Agency rightly acknowledges that CCS is a key climate change mitigation technology, and the proposed rules should s upport its development. The UIC rules should be designed to facilitate, and not hinder, the successful commercial scale deployment of CCS. As such th e rulemaking necessitates a host of regulatory approaches: recognition that ea rly adopters are likely to be EOR operators; grandfathering of existing wells which facilitates development of GS wells; appropriate character ization of CO2 and potential risks; avoidance of unnecessary stigmatization of GS; a rec ognition of the diversity of target formations (including especially unmin eable coal seam formations); an appreciation for the consequences of public perception; avoi dance of one-size fits-all approaches; and re gulatory certainty through limits and guidelines to Directors' discretion. Furt hermore, a successful CC S regime requires the avoidance of conflicts to the extent possible. Accordingly, GS should be
p romoted at sites where it has minima l risk to other uses of underground formations, such as natural gas storage.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

EPA clarifies that the intent of the GS rule is not to promote or encourage the use of GS; rather, its
p urpose is to ensure consistency in permitting underground injection of CO2 at GS operati ons across the United States and provide require ments to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: The potential environmental benefits of deploying CCS te chnologies, in terms of avoided or sequestered CO2 emissions, should be weighed against potential requirements that might delay or compromi se the ability to achieve commercialscale CCS. Ke y issues include balancin g state and federal interests, Commenter Name: Pamela Fa gg ert Letter ID: 0175 Commenter Or g anization: Dominion Comment ID: 23514

Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23550appropriate characterization of CO2, appropr iate risk management approaches and maintaining needed flexibility. To this e nd, EEI has provided comments on nine areas of concern, briefly summarized below.

Response: Please see the remainder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble, including site selection criteria , emergency and remedial respons e, and the adaptive rulemaking approach, as well as the rulemaking docket.

EPA clarifies that the intent of the GS rule is not to promote or encourage the use of GS; rather, its
p urpose is to ensure consistency in permitting underground injection of CO2 at GS operati ons across the United States and provide require ments to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Other EPA Comment Codes and Descriptions: 1330 1.1.3.1 Support use of GS in general Comment: EEI's views are guided by several general principles applicable to any federal legislative or regulatory effort on CCS, which are described below and discussed more fully in the context of specific comments:

1. Promotion of CCS. As EPA acknowledges in the preamble, CCS is a key climate change mitigation technology, and the proposed rules are intended to support its development.[FN2] Likewise, any EPA regulatory regime re lated to CCS developed under the authority of SDWA (or any other statute) should be designed to facilitate, and not unduly hinder, the succ essful commercial-scale deployment of CCS. The potential environmental benefi ts of such deployment in terms of reduced or avoided GHG emissions should be wei ghed against potential requirements that might delay or compromi se the ability to achieve commercialscale CCS. Issues the Agency should consider in connection with this principle include:

[FN2] 73 Fed. Reg. 43495, col.1.

Response: EPA clarifies that the intent of the GS rule is not to promote or en courage the use of GS; rather, its purpose is to ensure consistency in permitting undergr ound injection of CO2 at GS operations across the United States and provi de requirements to prevent endange rment of USDWs in anticipation o f the eventual use of GS to reduce CO2 emissions. Plea se see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: a. Reasonable regulatory approaches. Re gulations proposed for injection and storage should be carefully tailored to fit injection and storage projects and the true nature of the risks that th ey may pose, but should not be unduly burdensome for the regulated community. In particular, the following issues

Response: EPA believes that the final GS rule includes a balance of sp ecific criteria to be met b y the Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23562

Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23563owner or operator and areas of Dir ector discretion. The Agency believes this balance allows for GS
p rojects to be designed and permitted to address the unique, site-specific aspects of each project, while
p roviding consistency in permitting across the U.S.

Other EPA Comment Codes and Descriptions: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 Comment: 5. Anticipation of related developments. On the other hand, the Agency should strive to anticipate future statutory a nd regulatory developments in the climate change arena so that any rulemaking has a reasonable chance of melding with such developments. For instance, while it is clear that SDWA does not authorize the Agency to develop rules that specify any ki nd of "credit" system for capture and storage of CO2, the Agency can and should consider how its UIC rulemaking will fit with foreseeable features of potential future regimes and how rules can be drafted to complement such feat ures to the extent possible.

Response: EPA acknowledges that GS falls within the broader context of CCS and the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordina ted with other Agency program of fices and across federal agencies (e.g., with the Department of Energy; United St ates Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcem ent, formerly the Minerals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applic ability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

Comment: If promulgated as currently proposed, the Proposed Rule will have a significant and direct impact on the interests of the members of the CCS Alliance and their customers. The CCS Alliance believes the Proposed Rule is helpful in many ways, but also that it can be improved in a manner that will both promote good risk management and reduce barriers to CCS deployment.

Response: EPA acknowledges the comment. The purpose of the rule is to ensure consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. Please see the remai nder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory approac h, please see the final rule and preamble as well as the rulemaking docket. Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23573

Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23795

Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23797Comment: As the only significant technology to re duce atmospheric CO2 emissions from coal, CCS is indispensable to reducing GHG emissions while meeting energy demand and achieving energy security. It is true, as EPA notes, that underground storage of CO2 is "only one of a portfolio of options," including efficiency improvements, and the use of alternative and renewable energy sources. However, these other tools are not a substitute for baseload power generation, which comes primarily from fossil fuels. All GH G emission reduction options will need to be pursued to meet proposed emissi on reduction targets. The CCS Alliance urges that EPA, and those concerned wi th the Proposed Rule, consider the importance of CCS in the contex t of climate risk mitigation.

The U.S. population is expected to grow by 60 million by 2030. During that time, electricity demand is projected to incr ease by approximately 30 percent.[FN5] Without rapid deployment of technologies th at have begun to show promise, such as CCS, it will not be possible to meet the GHG emission reduction goals being discussed by IPCC and others now for atta inment by mid-century. While the thrust of this rulemaking is to protect and preserve USDWs, such environmental objectives should neither be viewed in isolation nor divorced from other environmental and policy considerations - including energy security, economic stability and trade consider ations. A rational, comprehensive approach to the management of CO2 emissions from GHG-emitting facilities must be undertaken if we are to simultaneously pr eserve economic stability, ensure returns on invested capital, enhance U.S. energy security, a nd mitigate the pred icted effects of climate change.

[FN5] Energy Information Administrati on, Annual Energy Outlook 2008 (June 2008), http://www.eia.doe.gov/oiaf/aeo/electri city,html; U.S. Census Bureau, Projections of the Population by Age and Sex for the United States: 2010 to 2050 (Aug. 2008), http://www.census.gov/population/www/projections/files/nation/ summary/np2008-12.xls.

Response: EPA clarifies that mitigating climate change is outside the scope of the GS rulemaking. Rather, the purpose of the GS regulation is to ensu re consistency in permit ting underground injection of CO2 at GS operations across the United States a nd provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: Conclusion

We appreciate the opportunity to provide th ese comments. CO2 use in EOR offers America the opportunity to produce billi ons of barrels of oil that would otherwise be imported from foreign na tions. These are existing American subsurface assets we should strive to optimize and Amer ica deserves these dual benefits of its own resources . EPA’s search for a regulat ory structure to manage the geologic sequestration of CO2 in the context of carbon capture initiatives has resulted in its proposal to create a new UIC category - Class VI. This approach reflects the reality that GS wells do not fall readily under the current UIC classes. Because of CO2 use in EOR, EPA’s proposal must be balanced

a g ainst an y risk it poses to limit the use of CO2 EOR. We have identified three Commenter Name: Lee O. Fulle r Letter ID: 0179 Commenter Or g anization: Independent Petroleum Associ ation of America et al. Comment ID: 23615specific concerns in these comments; others may be similarly significant. However, we believe that these three it ems - the relationship between Class II operations and the new Class VI GS wells, the threat of new liability risks and the federal-state relationship - must be positively addressed to assure that American can effectively produce its o il resources. If there are questions regarding these comments or if additi onal information is required, please contact Lee Fuller at IPAA, 202-857-4722.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional inform ation on EPA's final regulatory approach, including the discussion of the reperm itting of Class II/EOR wells for GS, pl ease see the final rule and preamble as well as the rulemaking docket.

Comment: - Protection of underground sources of drinking water (USDWs) should be the highest priority - water should trump everything! - Prevention of unintended consequenc es is of utmost importance;

Response: EPA agrees that protecting USDWs is a high prio rity. The purpose of the GS regulation is to ensure consistency in permitting underground injecti on of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. Please see the remai nder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final rule and
p reamble as well as the rulemaking docket.

Comment: - If USDW water quality is degraded by a GS project, the owner/operator of that
p rojects is responsible for any costs bor n by drinking water utilities due to increased treatment requirements for that ground water or replacement of lost capacity; and,

Response: As described above, EPA clarifies that the purpose of the GS regulation is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and
p rovide requirements to pr event endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: In its comments, AWWA makes several reco mmendations for the following specific items to be included in the final regulation:

- Requirement to consult with the state environmental department and affected water utilities to determine which aquife rs currently not classified as USDWs might be considered as futu re drinking water sources;

Response: As part of the UIC permit review process in 40 CFR §124, the UIC Pro g ram Director is Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23643

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23646

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23648required to notify certain stakeholde rs of any public hearings and the availability of the draft permit. EPA has added a requirement at §124.10( c)(1)(xi) that state and local oil and gas regulatory agencies and state agencies regulating mineral exploration and recovery, th e PWSS Program Director, and all agencies that oversee injection wells in the state must be notified as part of the public notice process for a Class VI permit. For additional information on EPA' s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: AWWA appreciates the oppor tunity to comment on the proposed requirements for geologic sequestration wells as publis hed in the July 25th, 2008 Federal Register (73 FR 43491). Protection of underground sources of drinking water (USDWs) should be a key priority of a ny geologic carbon sequestration regulation developed as part of the Underground Injection Control (UIC) Program.

Response: EPA agrees that protecting USDWs is a high prio rity. The purpose of the GS regulation is to ensure consistency in permitting underground injecti on of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. Please see the remai nder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final rule and
p reamble as well as the rulemaking docket.

Comment: I. GENERAL COMMENTS

In 2007, approximately 78% of 52,000 communi ty water systems in the United States were supplied by groundwater and these systems served 90.5 million
p eople. In addition, many surface water utilities are curr ently looking at conjunctive use and/or groundwater development as adaptation measures (supply
p ortfolio diversification/new storage) to combat climate change. Each of these utilities could potentially be impacted by geologic carbon sequestration, simply by the fact that these utilitie s utilize groundwater resources.

The proposed regulation is a good technical starting point given the evolving state of geologic sequestration; however, the proposed rule has many limitations that could allow for the endangerment of underground sources of drinking water (USDWs). Many of the require ments are based on faith, and not a lot of data, and the drinking water community is being as ked trust that geologic sequestration technology will work even though there is very little experience with this technology on a large scale. For example, the requirements for determining the direction of carbon dioxide plume migr ation, predicting confining layer containment potential, and identifying necessary geo-chemical monitoring are based on modeling exercises, with limite d monitoring data to validate these models and limited r eal-life data to support the requirements. There is the
p ossibility for unintended consequences to occur with geologic sequestration is very real, similar to what was observed wi th the use of MTBE. MTBE is the fuel additive that was meant to solve an air pollution problem but its use resulted in unanticipated drinkin g water pollution problems. Carbon dioxide is an ener gy Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23659

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23660p roduction/use byproduct that causes air pollution/climate problem but whose mitigation (using geologic sequestrati on) could cause drinking water contamination and other (s upply) problems. EPA needs to draw on the lessons learned from the MTBE situation, and do ev erything possible to prevent a similar situation from occurring with geologic se questration. Prevention is the key word here. AWWA will address thes e issues, as well as some other important concerns, in this section of general comments.

Response: EPA disagrees that GS is analogous to the MTBE situation. EPA believes that large scale GS can be done safely. The final rule is based on the most recent GS-related data, information, and scientific research available. EPA intends to continue to collect data on GS and to incorporate such data as it implements its adaptive approach to GS rulemaking to incorporate new resear ch, data, and information about GS. An adaptive approach provides Class VI ow ners or operators the flex ibility to use and apply newly developed technologies for GS as th ey become availabl e in the future.

The GS regulation builds upon the long-standing, protec tive regulatory framewor k of the UIC program, which has been regulating the injection of fluids fo r decades. The GS regulation enhances this existing framework with tailored requirement s for Class VI GS wells to addres s the unique nature of large scale GS of CO2. These protective requirements include extensive geologic testing, detailed computational modeling of the AoR and periodic re-evaluations, detailed requirement s for monitoring and tracking the CO2 plume and pressure front, and extended post-injection monitoring and site care.

Other EPA Comment Codes and Descriptions: 1600 1.3 Risk Associated with CO2 GS Comment: E. EPA Should Ensure that the Regulations for GS Are Not More Stringent or Prescriptive than Necessary to Protect USDWs.

EPA has recognized that it has two goals for the proposed rules for geologic storage of carbon dioxide: the protecti on of underground sources of drinking water [FN2/] and the promotion of th e development of carbon capture and storage.[FN3/] EPA Administrator Stephen Johnson noted when he announced the
p roposal that ""[t]oday's proposal paves the way for technologies that would
p rotect public health and help reduce the effects of climate change. With proper site selection and management, geologic se questration could play a major role in reducing emissions of carbon dioxide into the atmosphere."[FN4/] We urge EPA to keep both of these goals in mind and to work to ensure that the regulatory regime that is ultimately adopted is designed to facilitate - not delay or discourage - the successful commercial-scale development of carbon capture and storage. The potential emissions benefits of commercial-scale carbon storage are too large and too important to ignore in the context of these regulations.

[FN2/: 73 Fed. Reg 43492 (July 25, 2008) ("It proposes a new class of well and minimum technical criteria for the ge ologic site characterization, fluid movement, area of review (AoR) and corrective ac tion, well construction,operation, mechanical integrity testing, monitoring, well plugging, postinjection site care, and site closure for the purposes of protecting underground sources of drinking water (USDWs).").] [FN3/: EPA Press Release, "EPA Lays Groundwork for Promising Technologies to Help Miti g ate Climate Chan g e" (Jul y 15, 2008), Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24326http://www.epa.gov/safewater/ uic/wells_sequestration.html ("EPA is proposing a rule that supports promising technologies to prevent industrial emissions of carbon dioxide. Secure, long-term undergr ound storage of the greenhouse gas is one way scientific innovation could lessen the effects of climate change. . . . Carbon capture and storage is part of a portfolio of technologi es available to reduce greenhouse gas emissions. EPA is co ordinating with the Department of Energy on carbon sequest ration research and developmen t."); EPA Press Release, "EPA To Develop Regulations for Geologic Sequestration of Carbon Dioxide" (October 7, 2007) Id.] [FN4/: EPA Press Release (July 15, 2008).]

Unfortunately, in its effort to ensure protection of US DWs, EPA has exhibited a zeal that could materially impede, over burden, and effectively stigmatize GS. The preamble to the proposed rule repeat edly overstates the risks posed by CO2 injection while systematic ally understating the ex tent of knowledge and experience industry and regulators have gained through decades of practical experience with a wide range of inject ion well operations. As a result, the
p reamble presents an exhaustive review of every imaginable risk with respect to CO2 injection, but fails to disclose that many of these theoretical risks relate to implausible scenarios or concerns that - based on decades of robust operational and regulatory experience - are well understood and relatively easy to address. The scale of GS operations will certainl y be larger than many
p revious CO2 injection operations, but it is not as though we do not have extensive experience with CO2 injection or that there is any fundamental lack of understanding about what happens when CO 2 is injected underground. After all, there are already thousands of existing CO2 injection wells in operation that have injected hundreds of millions of t ons of CO2 largely without incident. Rather than provide appropriate context for the development of Class VI regulations, however, the proposed rule gi ves the impression that GS is an adventure into entirely uncharted seas. The proposed rule - having started by framing the issues in this way - then em ploys a regulatory approach that errs on the side of including excessively prescriptive, overl y-burdensome, and often redundant requirements.

Response: EPA disagrees that the GS requirements are ex cessive. The Agency believes that injecting large volumes of CO2 for GS poses unique challe nges that, if not properl y managed, could endanger drinking water sources or have other adverse impacts. EPA believes that caution is warranted and has, as a result, developed a new well cla ss with requirements tailored to address the unique challenges posed by GS and potential risks associated with long-term injection of CO2. These requirements include the tailored AoR delineation process per §146.84, monitoring that is appropriate to GS projects per §146.90, and extended post-injecti on site care per §146.93.

EPA acknowledges that industry has decades of experience with well construction and operation. For example, the oil and gas industry has experience drilling and cementing wells in very deep formations, in a variety of environmen ts (e.g., high-pressure and lo w-pressure formations), a nd for a variety of uses (e.g., injection, oil and gas production, monitoring). EPA believes that this experience has led to the development of well materials and construction and operating procedures that are applicable to Class VI wells.

As part of its adaptive rulemaking approach, the Agency plans, every six years, to collect and review data on GS projects to determine whether the a ppropriate amount and types of information andappropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

EPA clarifies that the GS rule does not promote GS in specific settings, nor does it limit injection activities to any specific type of formation, geographi c region, or depth. The focus of the GS rule is to ensure that, where GS is deployed, it is conducte d in a manner that is protective of USDWs.

Other EPA Comment Codes and Descriptions: 1600 1.3 Risk Associated with CO2 GS Comment: 1. The Proposed Class VI Requirements Are Far More Burdensome than Necessary to Protect USDWs.

As the preamble acknowledges, the actual human health and ecological risks associated with GS are relatively remo te and can be addressed effectively through measures implemented to protect USDWs. 73 Fed. Reg. at 43497-98. Unfortunately, having started with an ex aggerated sense of the risks involved and an inadequate rec ognition of the value of existing regulatory and operational experience relevant to CO2 injection, the proposed rule seems to
p roceed from the premise that the most strict UIC regulations in existence - those for hazardous waste injection - should serve as the starting point for the development of the Class VI regulations. This is not a logical or appropriate regulatory approach, because CO2 - which is found in abundance both in ambient air and in the subsurface - is nothing li ke hazardous waste and plainly does not warrant the same level of regulation. In fact, the principal issues with respect to CO2 injection for GS relate primarily to the mobility of CO2 and the sheer magnitude of the injection operations invol ved; these are not issues that the requirements for hazardous waste injecti on are particularly well suited to address.

The more logical starting point for devel opment of the Class VI regulations is the Class II regulations. As the propos ed rule recognizes, CO2 injection operations have been conducted pursuant to the Class II regulations for many years, and experience with thousands of wells injecting hundreds of millions of tons of CO2 demonstrates that the Cla ss II regulations - as applied to CO2 injection - are adequate to protect USDWs. This is certainly true with respect to the basic constructi on, operating, monitoring, and mechanical integrity testing requirements for injection wells; after all, what "works" in terms of the construction and operation of a CO2 injection well does not depend on the
p urpose for which CO2 is being injected. Accordingly, there is no reason why the Class VI requirements addressing issues such as well construction and mechanical integrity testing should be any different than the Class II requirements.

Unfortunately, the proposed Class VI requi rements are far more stringent than the Class II requirements, a fact that cr eates a need to "grandfather" Class II CO2 injection wells that remain in se rvice for GS purposes after EOR/EGR operations cease. Rather than resembling the Class II requireme nts, the proposed Class VI requirements are as stringent as those for hazardous waste injection in most respects. Indeed, many of the construction, mechanical integrity, monitorin g and financial assurance requirement s proposed for Class VI wells are Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24327even more comprehensive and more strict than those for hazardous waste injection wells. While some of these more burdensom e requirements are legi timately related to concerns about the mobili ty of CO2 or the anticipate d scale of GS operations, many - as discussed in Part III of these comments - are not.

Response: EPA disagrees that the GS requirements are exce ssive or are based on exaggerated risks; the Agency believes that injecting large volumes of CO2 for GS poses unique challenges that, if not
p roperly managed, could endanger drinking water sources or have other adverse impacts. EPA believes that caution is warranted and has, as a result, deve loped a new well class with requirements tailored to address the unique challenge s posed by GS and potential risks asso ciated with long-term injection of CO2. These requirements include th e tailored AoR delineation pro cess per §146.84, monitoring that is appropriate to GS projects per §146.90, and ex tended post-injection site care per §146.93.

EPA believes that the nature of CO2 injection for long-term storage is diff erent from Class II CO2 injection for ER, and that tailored requirements for Class VI wells are appropriate and necessary to
p rotect USDWs from endangerment. For this reason, the Agency tailored UIC requirements for Class VI wells that address the general risks deep inject ion may pose to USDWs and specifically address the unique nature of CO2 GS (i.e., very large volumes , very long time-periods, and reservoir pressure conditions).

Other EPA Comment Codes and Descriptions: 1680 1.3.8 Don't overstate risk, don't stigmatize CO2 Comment: 2. Rules that Stigmatize GS or Burden it Excessively Would Not be in the Public Interest.

The magnitude of the regulatory burdens imposed by the proposed Class VI requirements are of concern for several reasons. First, unnecessary regulatory burdens would act as a direct impediment and disincentive to the development of GS projects. Less directly, the imposit ion of unreasonably st ringent regulatory requirements - particularly requirements for multiple layers of requirements addressing the same basic risks - inherent ly magnify the impression of risk and could thus stigmatize GS and discourage investment in GS pr ojects. EPA should recognize that "more regulation" - partic ularly the "belt-and-suspenders plus more belts and more suspenders" approach reflected in the proposed rule - is not "better regulation" in the GS context. To the contrary, overly-burdensome regulation - to the extent it effectively impedes or deters use of a promising technology - could prove counterproductive.

We understand the importance of public perception when it comes to the siting and permitting of needed infrastructure, and believe strongly in the need to ensure that the public has accurate information. To facilitate the public’s appreciation of the merits of GS, we urge EPA to ensure that it does not overstate the risks associated with CO2 injection or understate the justified confidence with which many potential is sues and concerns can be addressed. Similarly, we urge EPA to avoid the impo sition of regulatory requirements that are so disproportionate to the risks involved that they may do more to incite than address public concerns. To this e nd, EPA should scale back its regulatory requirements to more accurat ely reflect the magnitude of actual risks and to ensure that an y requirements imposed are trul y necessar y for the protection of Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24328USDWs.

EPA should also consider the effect its re gulations might have on the ability to secure critical financial backing for GS projects. Any exaggera ted impression of the risks involved in GS could adversely influence financial institutions and impede efforts to obtain financing. The r ecent turmoil in the financial markets highlights how challenging the financing of new technologies may become. In a credit-constrained world, investors will be wary of putting their limited funds behind GS projects if they believe they are likely to endanger the environment or public health. Accordingly, EPA shoul d recognize the importance of the messages that it sends the financial wo rld through the regulations it imposes.

Permanent storage of CO2 can be accomplis hed safely and without harm to the environment as long as we apply the right knowledge base, detailed site-specific information, technical expertise, and sound management practices. However, we cannot implement an effective regulatory program for sequestering CO2 if the rules are based on the erroneous premise that CO2 represents an extreme hazard. It is therefore important that EPA send accurate messages about the nature of CO2 and the actual magnitude of the risk s associated with GS. It is also critical that EPA strike an appropria te balance by addressing the risks associated with GS without creating a regi me that effectively hinders or deters use of this key technology for reduction of carbon emissions.

Response: EPA disagrees that the GS regulation overstate s the risk of CO2 injection. EPA recognizes that injecting large volumes of CO 2 for GS poses unique challenges th at, if not properl y managed, could endanger drinking water sources and have other adverse impacts. However, with proper site selection, the final, tailored, Class VI re quirements address the large volumes of CO2 injected, its buoyancy,
p otential corrosivity in the presence of water, and potential impurities in the CO2 stream. In addition, EPA expects the tailored permitti ng, siting, construction, operation, mo nitoring, and post- injection site care requirements in the GS rule to prevent leakage from injection formati ons and protect USDWs.

EPA does not believe that the tailor ed requirements will create a negati ve public perception of GS. The Agency believes that a demonstration to the public th at GS projects are meeti ng the GS rule's tailored requirements will likely improve confidence in the project and help address public questions and

concerns.

Regarding the ability of owners or operators to secu re financial backing for GS projects, EPA believes that, like the public, financing entities will have improved confidence in pr ojects that incorporate multiple protective requirements. Please see the discussi on of financial responsibil ity in the preamble to the final GS rule.

Comment: period of the project. CCS is a developi ng technology and additional data and research findings will be av ailable regularly. Therefore, we recommend that EPA have a plan to update the regulation on a regular basis as well. Having a permit

Response: The final rule is based on the most recent GS-related data, information, and scientific research available. EPA plans, ever y six y ears, to collect and review data on GS pro j ects to determine Commenter Name: Diane VanDe Hei Letter ID: 0206 Commenter Or g anization: Association of Metropolitan Water Agencies (AMWA) Comment ID: 22212whether the appropriate amount and types of info rmation and appropriate documentation are being collected, and to determine if m odifications to the requirements ar e appropriate or necessary. An adaptive approach provides Class VI owners or operators the flex ibility to use and apply newly developed technologies for GS as they become available in the future.

Please see the remainder of EPA' s responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final ru le and preamble as well as the rulemaking docket.

Comment: It is important to recognize at the outse t the development of a viable, largescale commercial CCS program requires re solution of technical, policy, legal, and liability issues providing necessary re gulatory certainty that may be beyond the scope of this specific rulemaking.

Response: EPA acknowledges that GS falls within the broader context of CCS and the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordina ted with other Agency program of fices and across federal agencies (e.g., with the Department of Energy; United St ates Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcem ent, formerly the Minerals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applic ability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

Other EPA Comment Codes and Descriptions: 1630 1.3.3 RCRA/hazardous waste issues (seeking comment); 1640 1.3.4 CERCLA issues (seeking comment) Comment: This rulemaking can resolve some important policy and legal issues and, in doing so, help foster the development of a practical, commercially deployable CCS regulatory program. For example, the Final Rule can provide much needed clarity regarding (1) the potential for liabil ity under the Resource Conservation and Recovery Act ("RCRA") and the Comp rehensive Environmental Response, Compensation, and Liability Act ("CERCLA") resulting from CO2 injection and GS activities, and (2) the options for addressing long-term post-injection liability for Class VI wells . As discussed below, there are practical regulatory and legislative options available to resolv e these uncertainties that will help assure the public and the regulated comm unity that CO2 UIC activities can be conducted in a manner that is both safe and effective.

Response: EPA agrees that regulatory clarity is important. With respect to RCRA and need for regulatory clarity, EPA has decided to initiate a separate proposed ru lemaking specifically to examine the issue of RCRA applicabilit y to CO2 streams bein g g eolo g icall y sequestered, includin g the possible Commenter Name: Paul L. Carpinone Letter ID: 0212 Commenter Or g anization: Tampa Electric Compan y Comment ID: 22896

Commenter Name: Paul L. Carpinone Letter ID: 0212 Commenter Or g anization: Tampa Electric Compan y Comment ID: 22897option of a conditional exemption from the RCRA re quirements for CO2 GS in Class VI wells. EPA will consider these comments as pa rt of its development of that pr oposal. The Agency will consider issues particular to RCRA in the context of that separate rulemaking, and recommends that the commenter read that proposed rule when it is published. The Agency notes that commenters who wish to submit comments on the RCRA pr oposal will need to do so during the comment period for that rule. Finally, EPA also notes that the fi nal GS rule, which adds new regulat ions for Class VI wells under the Safe Drinking Water Act (SDWA), is not making any changes to the RCRA regulations.

Comment: As a mining company, NAC is very aware that geology varies throughout the country and within regions and locales. This heterogeneous mix of subsurface conditions makes it challenging to develop a regulatory program that can adequately address all situations and conditions that will be encountered.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble, includi ng the discussions of si te characterization and target formations for GS, as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1435 1.2.1.3 EPA should develop guidance Comment: 2. Reconsider shifting the burden to the States when not enough information is available. It appears that much research is needed to ensure that geologic sequestration can be conducted in a safe manner. When research data is not available, or when EPA is uncertain of the best way to address a situation, the burden of addressing the issue is shifte d to the states. Examples include corrective action methodology for ab andoned wells, materials used in construction of the wells, and the use of tracers among other issues. Oklahoma DEQ recommends that EPA prepare guida nce documents to address the above

concerns.

Response: EPA clarifies that such decisions would be made by the state, if the well is located in a state with Class VI primacy. Any state that wishes to obtai n primacy for Class VI wells will need to describe in their program descripti on the criteria that would be used to make determinations on topics the commenter mentions. See §145.23. EPA adds that it is developing guidanc e for states and tribes that describes the process of applyi ng for and receiving primacy for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues associat ed with developing GS regulations that are the equivalent of mini mum federal criteria and requireme nts. These are available on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm.

Other EPA Comment Codes and Descriptions: 5600 2.11 Comments related to UIC Program primacy for Class VI wells Commenter Name: Dennis R. James Letter ID: 0214 Commenter Or g anization: North American Coal Corporation (NAC) Comment ID: 22958

Commenter Name: Saba Tahmassebi Letter ID: 0218 Commenter Or g anization: Oklahoma Department of Environmental Quality (DEQ) Comment ID: 21563

Commenter Name: Jonathon Palm Letter ID: 0222 Commenter Or g anization: Nevada Division of Environm ental Protection, Bureau o f Water Pollution Control Comment ID: 21644Comment: 5. In implementing this rule, the state will be encumbered with increased financial and resource burdens in asse ssing the geologic sequestration permit submissions, evaluating the technical models, and making permitting determinations. Financial resource cons iderations should accompany eventual
p romulgation of the rule in order to en sure adequate funding for these various tasks.

Response: EPA acknowledges that there may be technical and administrative challenges including resource concerns, and will work closely with the states to assist th em in resolving funding issues or acquiring the resources, personnel, and training needed to addre ss the unique technical challenges associated with GS.

EPA will also incorporate Class VI wells into the UIC Program's grant allocation process. The States/Tribes/Territories must also demonstrate that they have ade quate resources to implement the
p rogram through matching resources against those allocated by the UIC Program's grant allocation formula. Currently, primacy programs are require d to meet a minimum of 25 percent matching requirement.

Comment: CURC has concerns about EPA’s proposed ru le. CURC believes that the final rule should be modified to provide: (a) greater regulatory certainty for CO2 storage in geologic formations, (b) balance betw een reducing the risk of potential impacts of injected CO2 on underground sour ces of drinking water (or USDW), and increasing the likelihood that overly stringent UIC rules could lead to delays in the commercial adoption of CCS technology and ultimate ly less CO2 mitigation, (c) a regulatory design that accommodates gr eater flexibility in permitting CO2 injection, (d) interim guidance for GS projects for the period that precedes
p romulgation of the final UIC rule, and (e) no interference with ongoing regulatory programs that govern the commercial injection of CO2 for enhanced oil or methane recovery.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

EPA clarifies that the GS rule does not promote or encourage the use of GS; rather it is designed to ensure consistency in permitting underground injecti on of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA adds that the fina l GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Direct or discretion. The Agency believes this balance allows for GS projects to be desi gned and permitted to address the uni que, site-specific aspects of each
p roject, while providing consistency in permitting across the United States.

Other EPA Comment Codes and Descriptions: 2400 1.8 Comments on EPA's adaptive rulemaking
p rocess Comment: EPA’s proposed rule includes a number of requirements that could create Commenter Name: Ben Yama g ata Letter ID: 0227 Commenter Or g anization: Coal Utilization Research Council Comment ID: 21779

Commenter Name: Ben Yama g ata Letter ID: 0227 Commenter Or g anization: Coal Utilization Research Council Comment ID: 21781significant uncertainty as CCS project developers initiate projects. These requirements will serve as barriers to CC S project developers who will need a clear idea of their environmental obligat ions and financial exposures before such projects are initiated. In genera l, we believe that the "adaptive" regulatory approach, as set forth in Secti on III.B. of the Preamble, will lead to regulatory uncertainty. Sp ecifically, the NOPR states that "EPA will track implementation of the final GS rule to determine whether these requirements continue to meet SDWA objectives and, if not, revise them as needed." Formulating regulations on th e best available scientific information available is appropriate but these NOPR statements signal an intent that the regulations could be modified before , during or after the in itial regulations are
p romulgated. This ability to exercise such broad discretion will discourage entities considering CCS projects from m oving forward. It is important for EPA to retain discretion to amend its rules, but to limit such discretion to be exercised within stated criteria; to pr ovide notice and opportunity for comment; and to apply any modifications prospe ctively, allowing projects already operating under valid permits to continue to operate pursuant to regulations in
p lace at the time such permits were issued.

Response: EPA acknowledges that the UIC GS adaptive rulemaking approach introduces a degree of uncertainty—given that the GS requirements may change in the future. However, the Agency believes that there is also a need to pro ceed with regulatory development at a pace that can meet the current and future demands for Class VI permits, and allow early projects to be permitted under the tailored Class VI regulatory approach.

EPA believes that an adaptive approach to regul ating CO2 injection for GS will allow regulatory development to proceed and ensure USDW protec tion from endangerment while EPA continues to gather data from pilot projects and other research as it becomes available. Additionally, the Agency believes that there is a need to have regulations in place during the earliest phases of GS deployment. Finalizing requirements at this time will allow early GS wells to be permitted in a manner that addresses the unique characteristics of CO2 injection for GS and allow early projects to demonstrate successful confinement of CO2 in a manner that is protective of USDWs. EPA also believes that an adaptive approach enables the Agency to make changes to th e program as necessary to incorporate new research, data, and information about GS and associated tec hnologies (e.g., modeling and well construction). This new information may increase protectiveness, streamline implemen tation, or otherwise inform the requirements for GS injection of CO 2. Any revisions that will be made to the GS requirements in the future will go through public notice a nd comment as required by the SDWA.

Regarding the comment that projects operating under valid permits should be able to continue to operate
p ursuant to regulations in place at the time of pe rmit issuance, EPA notes that changes to the GS regulation may trigger permit m odifications under existing regulati ons at 40 CFR 144.39(c), which may trigger public notice and comment proc edures under Part 124. EPA adds that the final GS rule allows the construction of existing Class I, Cl ass II, or Class V experimental technology wells to be grandfathered, at §146.81(c), provided the owner or operator can demonstrate to the Director that the wells were engineered and constructed to m eet the requirements at §146.86(a) and ensure protection of USDWs, in lieu of requirements at §§146.86(b) and 146.87(a).

Comment: B. The Need for Balanced Re g ulation Commenter Name: Ben Yama g ata Letter ID: 0227 Commenter Or g anization: Coal Utilization Research Council Comment ID: 21786We agree that a regulatory structure for GS wells is urgently required for CO2 injection outside of appli cations for enhanced recovery of stranded oil and methane. Most important, the final rules must insure the primacy of protecting our nation’s drinking water as we begin a program to sequester CO2. However, the UIC regulations must not inadvertentl y create uncertainty or establish a regulatory program that actu ally discourages the geologically and geographically diverse commercial deployment of CCS. We appreciate the level of certainty that the proposed rule seeks to achieve for CCS project developers in light of the need to protect drinking water, yet there are several areas of the proposed rule that we believe require the EPA to document the need for the level of proposed stringency, or to consider reducing that stringency. This need for explanation or modification applies to the following elements of the proposed rule:

Response: EPA clarifies that the GS rule does not promote or encourage the use of GS; rather it is designed to ensure consistency in permitting underground in jection of CO2 at GS operations across the United States and provide require ments to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO 2 emissions. EPA believes that the GS regulation will provide regulatory certainty and oversight that operators ha ve requested, and allow for the deployment of this key climate change miti gation technology that could be deployed to reduce CO2 emissions. EPA adds that the GS regulation builds upon the long-standing protective framework of the UIC Program, which has been regulating the injection of billions of gallons of fluids fo r decades, including wells used for enhanced oil recovery.

Other EPA Comment Codes and Descriptions: 1435 1.2.1.3 EPA should develop guidance Comment: D. Interim Program Recommendations

CURC proposes that EPA consider issuing guidance to create an interim program that would provide a regul atory framework for CCS projects prior to the
p romulgation of a final rule. Our concer n rests with the possibility that the final rules may not be issued for some time in the future. For example, a section in the preamble to the NOPR states:

During the Deployment Phase (1008-1017), the [RCSP] partnerships will conduct large volume carbon storage tests to demonstrate that large-scale CO2 injection and storage can be achi eved safely and economically. EPA will use the data collecte d from these projects to support decisions in the final GS rule.

This statement suggests that a final GS rule may not be issued until 2017 or that rules issued earlier than that date could be modified and changed later. While we ascribe to a belief that any final rule should be informed by the findings and data collected through RCSP pa rtnerships, we are concerned that regulatory uncertainty will delay CCS project development; hence the need for an interim program.

Projects issued permits under this guidance would collect data and technological experience that could contribute information necessar y to establish a viable Commenter Name: Ben Yamagata Letter ID: 0227 Commenter Or g anization: Coal Utilization Research Council Comment ID: 21794working framework for a long term permit ting and liability regime for geologic CO2 storage activities. The program might be limited to a maximum number of
p rojects, or cumulative amount of CO2 injection, and it should be designed to be compatible with anticipated financial incentives for "early adopters" of CCS technology. Projects permitted under this interim guidance should be grandfathered from the final UIC rule.

Specific limiting provisions could be required in order to ease any concerns regarding the endangerment of USDW under such an interim program. Since proper site characterization is the most effectiv e risk management tool for GS wells, EPA could require applicants under this program to use geologically superior sites, or provide alternative requirements for sites with significantly superior characteristics. The World Resource Inst itute (WRI) CCS Guidelines [FN5] and IOGCC model rules include provisions for selecting storage sites that have a high probability of retaining injected CO2. [FN6] An interim program would recognize the same goals sought by EPA when it issued its guidance for DOE Regional Partnership pilot projects designe d to evaluate the technical issues associated with CO2 injection as Class V experimental tec hnology wells. [FN7]

[FN5: World Resource Institute, "CCS Guidelines: Guidelines fo r Carbon Capture, Transport and Storage" (2008) . The WRI Guidelines also offer a comprehensive regulatory approach to CCS that goes beyond the regulation of GS wells. However, in the guideline’s discussion of site closure, the WRI acknowledges a need for proper incentives so as not to impede the de ployment of CCS technology as private companies may be reluctant to engage in storage operations if required to carry a financial commitment and liability out into the indefinite future. Id. at 104.] [FN6: The IOGCC model rules premise appr oval of a GS storage site on four findings: (1) the facility and reservoir are suitable and feasible for injection and storage; (2) that a good faith effort has been made to obtain the consent of a majority of the owners having propert y interests affected by the storage facility, and that the operator intends to acquire any remaining interest by eminent domain or otherwise allowed by stat ute; (3) that the use of the storage facility will not contaminat e other formations containing fresh water, oil, gas, coal or other mineral deposits; and (4) that the proposed storage will not unduly endanger human health and the environment and is in the public interest. See IOGCC Model Rules, supra note 5 at Appendix I.] [FN7: Envtl. Protection Agency, Office of Ground Water and Drinking Water, UIC Program Guidance #83, Using Class V Experi mental Technology Well Classification for Pilot Geologic Sequestration Projects (2007).]

Response: EPA disagrees that an interim program is necessary. EPA believes that sufficient data have been collected to inform the final GS rule. In addition to laboratory studies and modeling research that
p rovide relevant information on GS, the Agency is also collecting a nd analyzing GS project data and
p ermit information from a variety of sources. Most notably, EPA has evaluated permits and reviewed operational data and information associated with the seven regional carbon sequestration partnerships funded by the U.S. Department of Energy and coordinated through the National Energy Technology Laboratory. EPA believes that these projects form a solid basis for finalizing the GS requirements, and there is no reason to wait until all phases of the DOE demonstration tests ar e complete. Nevertheless, EPA anticipates that future experi mental and full-scale projects will continue to inform the technology, and is therefore using an adaptive rulemaking appr oach. The Agency plans to, every six years, collectand review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collecte d, and to determine if modifications to the requirements are appropriate or ne cessary. EPA believes that the completion of the DOE pilots in 2017 will allow the incorporation of results of thes e projects into the firs t review of the rule.

EPA clarifies that this rule does not allow grandfathering. However, under §146.81 owners or operators seeking to convert existing Class I, Class II, or Class V experiment al wells to Class VI geologic sequestration wells must demonstrate to the Director that the wells were engineered and constructed to meet the requirements at §146.86(a) and ensure prot ection of USDWs, in li eu of requirements at §146.86(b) and §146.87(a).

Comment: E. Conclusion

CURC understands EPA’s position that the SDWA does not provide EPA with the authority to develop regulations for all questions and issues related to GS. While a full regulatory framework is nece ssary for CCS projects to move forward, CURC recommends that EPA work within the UIC program to create necessary regulatory certainty for early CCS projec ts. EPA should acknowledge that overly

Response: EPA clarifies that the GS rule does not promote or encourage the use of GS; rather it is designed to ensure consistency in permitting underground in jection of CO2 at GS operations across the United States and provide require ments to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO 2 emissions. EPA believes that the GS regulation will provide regulatory certainty and oversight that operators ha ve requested, and allow for the deployment of this key climate change mitigation technology that could be deployed to reduce CO2 emissions. Please see the remainder of EPA's responses to this comment for further details.

Other EPA Comment Codes and Descriptions: 1435 1.2.1.3 EPA should develop guidance Comment: proposed. Lastly, CURC recommends that EP A issue guidance for an interim Class VI program for CCS projects that predate the final UIC rule.

Response: In advance of the GS rulemaking, EPA deve loped UIC Program Guidance # 83: Using the Class V Experimental Technology Well Classification for Pilot Carbon GS Projects (USEPA, 2007), which provides recommendations for permit writers regarding the use of the UIC Class V experimental technology well classifi cation at demonstration GS project s while ensuring USDW protection.

EPA disagrees that an interim program is necessar y. EPA believes that sufficient data have been collected to inform the final GS rule. In additi on to laboratory studies and modeling research that
p rovide relevant information on GS, the Agency is also collecting a nd analyzing GS project data and
p ermit information from a variety of sources. Most notably, EPA has evaluated permits and reviewed operational data and information associated with the seven regional carbon sequestration partnerships funded by the U.S. Department of Energy and coordinated through the National Energy Technology Laboratory. EPA believes that these projects form a solid basis for finalizing the GS requirements, and there is no reason to wait until all phases of the DOE demonstration tests ar e complete. Nevertheless, EPA anticipates that future e xperimental and full-scale pro j ects will continue to inform the technolo gy , Commenter Name: Ben Yama g ata Letter ID: 0227 Commenter Or g anization: Coal Utilization Research Council Comment ID: 21795

Commenter Name: Ben Yama g ata Letter ID: 0227 Commenter Or g anization: Coal Utilization Research Council Comment ID: 21801and is therefore using an adaptive rulemaking appr oach. The Agency plans to, every six years, collect and review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collecte d, and to determine if modifications to the requirements are appropriate or ne cessary. EPA believes that the completion of the DOE pilots in 2017 will allow the incorporation of results of thes e projects into the firs t review of the rule.

EPA clarifies that this rule does not allow grandfathering. However, under §146.81 owners or operators seeking to convert existing Class I, Class II, or Class V experiment al wells to Class VI geologic sequestration wells must demonstrate to the Director that the wells were engineered and constructed to meet the requirements at §146.86(a) and ensure prot ection of USDWs, in li eu of requirements at §146.86(b) and §146.87(a).

EPA clarifies that following finali zation of the GS rule, all GS proj ects that are not for experimental
p urposes must be re-permitted as Class VI wells and be subject to the final GS rule requirements.

Other EPA Comment Codes and Descriptions: 1500 1.2.2.2.4 Some other agency should regulate GS Comment: As noted in our joint comments with US WAG, many complex te chnical and legal issues will have to be resolved before geologic sequestration of CO2 can become a reality, and this will require a coope rative effort among several federal agencies, including EPA, the Department of Transportation, and the Federal Energy Regulatory Commission. The General Accounting Office ("GAO") recently issued a report entitled "Climate Change - Federal Actions Will Greatly Affect the Viability of Carbon Ca pture and Storage As a Key Mitigation Option" (GAO-08-1080, September 2008) (" GAO Report"), which emphasizes that significant technological barriers involving CO2 captur e technologies, as well as regulatory and legal uncertainties involving CO2 stor age, leakage, and ownership issues, must be resolved before a successful CO 2 CCS program of the scale envisioned by
p olicymakers can be achieved. GAO Report at 3-5. A National Academy of Sciences

Response: Regarding the need for a CCS agency to coor dinate across agencies , EPA is coordinating with and will continue to faci litate communication among federa l and state agencies during the implementation phase of the GS regulation.

Comment: 9. The proposed rules for Class VI GS well s are more stringent than the other UIC well classes (73 FR 43524-43525) yet th ey do not comprehensively manage issues of concern for GS. With this lim itation, the proposed ru les run the risk of locking in a regulatory framework th at ultimately inhibits widespread commercial deployment of CCS.

Response: EPA clarifies that the GS rule does not promote or encourage the use of GS; rather, it ensures consistency in permitting underground injection of CO2 at GS operations across the United States and
p rovides requirements to prevent endangerment of USDW s in anticipation of the eventual use of GS to reduce CO2 emissions. EPA believes that the GS re gulation will provide the regulatory certainty and oversi g ht that operators have reque sted, and allow for the deplo y ment of this ke y climate chan g e Commenter Name: Pamela A. Lace y Letter ID: 0228 Commenter Or g anization: American Gas Associatio n Comment ID: 21806

Commenter Name: M. Granger Morgan Letter ID: 0233 Commenter Or g anization: Carnegie Mellon University on behalf of the CCS Reg Project Comment ID: 21900mitigation technology that could be deployed to reduce CO2 emissions. Please see the remainder of EPA's responses to this comment for further details.

Comment: Conclusion

26. The CCS Regulatory Project shares EP A's commitment, and that of other
p articipants in the national discussion, to advancing the potential for safe and effective geological sequestration of car bon dioxide. To that end, the agency's draft rules are, subject to the specific concerns raised in our comments, a laudable effort to define a regulatory framework for assuring that carbon capture and sequestration proceed in a manne r that is calculated to protect the nation's water supply. But, in our judgment, the objectives we share with EPA are best served by a regulatory scheme th at takes into account, and ultimately advances, the full range of environmental imperatives that drive the development of CCS in the first place. With the impe nding advent of a new administration and a new Congress, both of which are expected to be attentive to issues related to climate change, the potential for near-term legislativ e action is relatively high. In these circumstances, EPA should consider using existing regulatory authority under the UIC program to license the first few CCS projects, but wait to finalize rules for GS wells until they can be drafted under the authority of new or amended legislation that enab les more comprehensive regulation.

Response: The final rule is based on the most recent GS-related data, information, and scientific research available. EPA believes th at sufficient data have been coll ected to inform the final GS rule. N evertheless, EPA anticipates that fu ture experimental and full-scale projects will continue to inform the technology, and is therefore using an adaptive rulemaking approach. EPA plans, every six years, to collect and review data on GS projects to determ ine whether the appropria te amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

Comment: Indiana is a member of the Interstate Oil and Gas Compact Commission (IOGCC). In 2002, the IOGCC established a Geological C02 Sequestration Task Force chaired by Lawrence Bengal, Director of the Arkansas Oil and Gas Commission. Its membership initially included representatives from IO GCC member states and international affiliate provinces, state and provincia l oil and gas agencies, DOE, DOEsponsored Regional Carbon Sequestration Partnerships, the Association of American State Geologists (AASG), and th e oil and natural gas industry. Later on the Task Force added representatives from EPA, and the U.S. Bureau of Land Management (BLM) attended as observers. This Task Force engaged in a thorough examination of the technical, policy, and regulatory issues related to the safe and effective storage of C02 in subsurf ace geological media (oil and natural gas fields, coal seams, and deep saline formations) for both enhanced hydrocarbon recovery and long-term C02 storage. Commenter Name: M. Granger Morgan Letter ID: 0233 Commenter Or g anization: Carnegie Mellon University on behalf of the CCS Reg Project Comment ID: 21918

Commenter Name: Robert E. Carter Jr. Letter ID: 0236 Commenter Or g anization: Indiana Department of Natural Resources (IDNR) Comment ID: 23203The products of the Task Force effo rts were the following two reports:

1. "Final Report" for DOE Aware No. DE-F C26-03NT41994, Amendment No. AOOO, dated January 24, 2005. This report contained an assessment of the current regulatory framework applicable to carbon capture and geologic storage and recommended regulatory guidelines and guidance documents for the states and provinces.

2. "Storage of Carbon Dioxide in Geologi c Structures - A Legal and Regulatory Guide for States and Provinces" date d September 25,2007. A thorough assessment of property rights issues relating to the underground space used for CCGS, and an overview of model general rules and re gulations for CCGS along with a Model Statute and a Model General Rules and Regulat ions for CCGS were included in this report.

We believe these two reports present the mo st practical and workable models for the regulation of CCGS and we encourage EPA to strongly consider them as it continues its process of fina lizing the Class VI CCGS rule. We have not included them as attachments to our comments as we know they have alre ady been submitted to EPA.

Additionally, we also know that detailed comments on the above referenced rules have been prepared and submitted to EPA on behalf of the IOGC C. IDNR supports the IOGCC comments and strongl y encourages EPA to take them into consideration as the final rules are being considered. Except for a few specific comments on topics that we believe do warrant extra em phasis, we do not think it necessary to restate every issue already addressed through the IOGCC comments.

Response: EPA acknowledges the comment. EPA adds that it has reviewed the IOGCC's reports and that information provided by IOGC C throughout the rulemaking proce ss has informed many technical aspects of the rule. EPA appreciates the input and effo rt that IOGCC has provided, as well as those from other state and private stakeholder consortia.

Please see the remainder of EPA's responses to this comment and IOGC C’s comment for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: A. The OCD has participated in prepari ng, and is generally supportive of, the comments presented by the Interstate Oil and Gas Compact Comm ission (IOGCC) and the Ground Water Protecti on Council (GWPC).

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment and comments from IOGCC and GWPC for further details. For additional information on EPA's final regulatory approa ch, please see the final rule and preambl e as well as the rulemaking docket.

Comment: Overall, the proposed rule makes g ood strides at addressin g some of the ke y Commenter Name: Mark E. Fesmire Letter ID: 0237 Commenter Or g anization: New Mexico Oil Conser vation Division (NMOCD) Comment ID: 23208

Commenter Name: Kristin Henr y Letter ID: 0242 Commenter Or g anization: Sierra Environmental Law Program, Sierra Club Comment ID: 23308issues for geological sequestration. Howeve r, there are several areas that need improvement as we discuss below. Firs t we briefly provide background on the infancy of large-scale CCS deployment, t echnical complexities, and the import of rapid development of CCS to tackle the global warming crisis

Response: EPA acknowledges the comment. The final rule is based on the mo st recent GS-related data, information, and scien tific research available. EP A intends to continue to collect data on GS and to incorporate such data as it implements its adapti ve approach to GS rulemaking to incorporate new research, data, and information about GS. An adaptive approach provides Class VI owners or operators the flexibility to use and apply ne wly developed technologies for GS as they become available in the future. Please see the remainder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final ru le and preamble as well as the rulemaking docket.

Comment: A Few Critical Changes Are Needed in the Proposed Rule

EPA must be applauded for ta king a critical step toward climate change goals by
p roposing the first rule to regulate carbon injection and storage. However, the
p roposed rule does not fully reflect the current emerging state of CCS technology. EPA recognizes th e rule must strengthen science, technology, and institutions in order to support a strate gy to address climate change. [FN14] The suggestions outlined be low would do just that:

[FN14: Proposed rule at p. 23.]

Response: The final rule is based on the most recent GS-related data, information, and scientific research available. EPA intends to continue to collect data on GS and to incorporate such data as it implements its adaptive approach to GS rulemaking to incorporate new resear ch, data, and information about GS. An adaptive approach provides Class VI ow ners or operators the flex ibility to use and apply newly developed technologies for GS as they become availa ble in the future. EPA clarifies that the intent of the GS rule is not to promote or encour age the use of GS; rather, its purpose is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and
p rovide requirements to pr event endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: The rule also lacks opport unities for public particip ation, ignores the very important question of liab ility, and requires a few de finition tweaks. Finally,

Response: EPA acknowledges the comment and disagrees th at the rule lacks opportunities for public
p articipation. GS permitting authorit ies must follow the existing public participation requirements for UIC permits as specified in 40 CFR 25 and 40 CFR Part 124. These regulations lay out the procedures for decision making and include requirements such as requiring the Director to notify the public regarding the availability of the draft permit and a llow him or her to request a public hearing on the draft
p ermit. Encouraging public part icipation allows the permitting authority to understand public viewpoints, preferences, a nd concerns about the pro j ect, which mi g ht help avoid public misperceptions Commenter Name: Kristin Henr y Letter ID: 0242 Commenter Or g anization: Sierra Environmental Law Pro g ram, Sierra Club Comment ID: 23313

Commenter Name: Kristin Henry Letter ID: 0242 Commenter Or g anization: Sierra Environmental Law Pro g ram, Sierra Club Comment ID: 23316about the nature and safety of GS projects and fo restall resistance later in the permitting effort.

Please see the remainder of EPA' s responses to this comment for further details. For additional information on EPA's final regulat ory approach, including the discus sion of the public participation requirements and long-term liability, please see the fi nal rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1310 1.1.2.4 Comments on other "out of scope" issues, e.g., pore space ownership Comment: WEST Associates Comments on the Proposed Rule

The following are WEST's comments on the Preamble and proposed rule, which we believe will clarify and strengthen the proposal:

–Under the proposed UIC regulation, siting UIC wells for GS in the west will likely involve a challenging set of nationa l agencies, states, and tribal sets of regional and sub-regional regulation that will require streamlining in order to site UIC wells and pipe lines to transfer super critical CO2 to GS sites located at some distances away from coal fired power plants. Such projects will cross over many jurisdictions and i nvolve a patchwork of regulatory requirements. This will require coordination among federal and tribal j urisdictions since it is hi ghly likely that most west ern projects will impact federal lands, including tribal lands. EP A should immediately start working towards building support and consensus am ong the federal land managers and BIA for the UIC regul atory program.

Response: EPA understands that the CO2 plumes for la rge GS projects may cross State, Tribal, Territorial, EPA Regional, or national boundaries. The final GS rule, at §146.82(a)(2), requires the owner or operator to identify all State, Tribal, and Territorial boundaries within the AoR. Based on this information, the Director mu st provide written notification to all St ates, Tribes, and Territories to inform them of the permit application §146.82(b) and ensure that they are involved in any necessary processes (e.g., development of the emergency and remedial response plan (§146.94)). The Agency encourages transparency in the permitting process and anticipa tes that State-State/State-Tribal communication on GS permitting will faci litate information sharing and enco urage safe, protective projects.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule. Commenter Name: Kevin Wanttaja Letter ID: 0248 Commenter Or g anization: Western Ener gy Suppl y and Transmission Associates Comment ID: 22240Other EPA Comment Codes and Descriptions: 1530 1.2.3.1 State regulatory e fforts on GS (seeking comment) Comment: – EPA needs to design the UIC program to facilitate GS sites that can be utilized by many individual power plants that may not have ready access to geologically suitable GS sites in proximity to such plants. What will be needed is state, tribal and federal cooperation to develop regional storage sites that could accommodate CO2 from sources in se veral states. Development of such regional storage sites would allow crit ically needed sharing pore space in states that have the most favorable geology.

Response: EPA encourages owners and operators and pe rmitting authorities to coordinate where multiple injection operations are planned, but notes that the rule does not require such coordination. EPA notes that the impacts of multiple operators in jecting into hydraulically connected formations must be accounted for in the AoR modeling required at §146.84, which must be based on detailed site-specific geologic data collected during the site characterization process in cluding consideration of existing conditions (e.g., current injection act ivities). Please see the discussion of AoR and Corrective Action in the preamble to the final ru le for additional information.

EPA adds that regulation of pore space ownershi p is outside the scope of this rulemaking.

Comment: Clearly, a viable large-scale commercial CCS program requires resolution of a broad range of technical, policy and legal questions, most of which are beyond the scope of this rulemaking. A good synopsis of those challenges was documented in the recent General Account ing Office ("GAO") report, "Climate Change - Federal Actions Will Greatly Affe ct the Viability of Carbon Capture and Storage as a Key Mitigation Option" (GAO-08-1080, Septem ber, 2008). That said, we think EPA’s efforts here are an importa nt first step and will set the tone for how EPA and other federal and state regulatory bodies will approach CCS going forward.

This rulemaking will also se t the tone for how the public perceives CCS. Public acceptance is a crucial linc hpin to any meaningful CCS program. This point was emphasized in a 2007 National Academy of Sc iences report, which noted that a large-scale CCS program cannot be successful "if a si gnificant fraction of the
p ublic views it as dangerous or unacceptable." (Nationa l Research Council, NAS, Prospective Evaluation of Applied Energy Research and Development of DOE (Phase Two) (2007).

Response: The GS regulation will provide certainty to industry and the public by providing consistency in requirements across the U.S. and transparency about what requirement s apply to owners or operators. Furthermore, the tailored requirements in the GS rule will help allay public concerns about the technology and its impacts on USDWs and, in tu rn, promote acceptance of GS projects.

EPA acknowled g es that GS falls within the broader context of CCS and the need for re g ulator y clarit y to Commenter Name: Kevin Wanttaja Letter ID: 0248 Commenter Or g anization: Western Ener gy Suppl y and Transmission Associates Comment ID: 22241

Commenter Name: James T. Sims Letter ID: 0249 Commenter Or g anization: Western Business Roundtable Comment ID: 22255ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Minerals Management Service; and the Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research, and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

Comment: One of the biggest impediments to comm ercial-scale CCS projects today is regulatory uncertainty. Meaningful invest ments in CCS will only occur in the
p resence of clear, carefully tailored regul atory constructs that help encourage early and robust development of projects and which aid in eliminating liability risk for such early investments. In that regard, we appreciate EPA’s statement, in the rule’s preamble, that it rec ognizes CCS as a key climate change mitigation technology and that the rule is intended to support its development.

With that goal in mind, we would offer the Agency th e following thoughts on how the proposed regulations might be clarified and strengthened:

Response: EPA believes that the GS regulation will pr ovide regulatory certaint y and oversight that operators have requested, and allow for the deployment of this key climate change mitigation technology that could be deployed to reduce CO2 emissions. EPA adds that the GS rule does not
p romote or encourage the use of GS; rather, it is designed to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory approach, please see the final ru le and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 2020 1.5.1 Support Class VI designation Comment: D. General Comments

Timing of promulgation

The proposed rule is based on a risk manage ment approach and is written in a way that should avoid unintended c onsequences to USDWs. It is important to bear in mind that CO2 injection projects can alrea dy be permitted today. While this may be adequate to protect USDW s in certain cases, it is in the interests of the
p ublic (and the re g ulated industr y ) to have a new in j ection class, desi g ned from Commenter Name: James T. Sims Letter ID: 0249 Commenter Or g anization: Western Business Roundtable Comment ID: 22258

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22282the outset with the particular charac teristics of GS in mind, as soon as
p ossible. This is necessary in order provide certainty and adequately safeguard
p ublic health and the environment. If the final rule incorporates changes concerning the adaptive nature of the rule and permits, as our Environmental NGO Group suggests, the Agency, and its state c ounterparts, will be able to deal with such unintended consequences to USDWs through the rule’s performancebased
p rovisions, review and a pos sible reissuance of permit s if necessary, and by revising the rule text if appropriate.

Response: EPA agrees that the tailored requirements fo r Class VI wells, pursuant to the final GS rulemaking, are necessary to address the unique nature of injecting large volumes of CO2 and to ensure that USDWs are protected from endange rment, and that a new well Cla ss specific to GS is appropriate. The GS rule contains tailored requirements for the permitting, geologic site characterization, AoR and corrective action, well construc tion, operation, mechanical integrit y testing, monitoring, well plugging,
p ost-injection site care, and site closure of GS wells that directly addr ess issues unique to the nature of large-scale CO2 injection for GS.

EPA adds that it continues to m onitor research being conducted on GS and will use this to inform its adaptive rulemaking approach. EPA plan s, every six years, to collect and review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirement s are appropriate or necessary.

Other EPA Comment Codes and Descriptions: 1640 1.3.4 CERCLA issues (seeking comment); 2020 1.5.1 Support Class VI designation Comment: We consider the Phase III Deployment Phas e of the Department of Energy’s (DOE) Regional Partnership Program to be very worthwhile, but we do not consider the completion of this program to be a prerequisite for either commercial implementation of CCS or for the promul gation of a sound and protective rule. The DOE’s program has limited funds available through appropriations, and its demonstration projects will be of limited scale and duration. In addition, it focuses as much or more on the optimum wa y to apply existing technologies as it does on fundamental research or even dem onstrations that particular technologies "work." Our scientific and practical unders tanding and experience in GS itself, as well as in related underground injection activities, is sufficient to construct and operate the first large-scal e, commercial plants in the U.S.,
p rovided they are regulated adequately. In that respect, we do not consider the
p roposed rule premature, but a very timely and necessary development.

The rule itself, rather than individual permits, should assure that Class VI
p ermits do not allow responsible parties to avoid CERCLA liability on grounds that a release constitutes a "f ederally permitted release"

Response: EPA agrees that tailored requirements for Cla ss VI wells are necessary to address the unique nature of injecting large volumes of CO2 and to en sure that USDWs are protected from endangerment. The GS rule contains tailored requirements for the permitting, geologic site characterization, AoR and corrective action, well construc tion, operation, mechanical integrit y testing, monitoring, well plugging,
p ost-injection site care, and site closure of GS wells that directly addr ess issues unique to the nature of lar g e-scale CO2 in j ection for GS. Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22283EPA believes, as supported by the rule 's administrative record, that sufficient data and experience currently exist to develop UIC regulations for GS wells. The GS rulemaking builds upon decades of knowledge about safe injection practices. While developing the GS regulat ion, EPA has evaluated relevant GS research, includi ng projects conducted by the se ven regional carbon sequestration
p artnerships funded by the U.S. Department of Energy and coordinated through the National Energy Technology Laboratory (NETL), and several internati onal projects. Additionally , EPA's Office of Water continues to fund research at the Lawrence Berkel ey National Laboratory examining the effects of CO2 interaction with ground water aquifers and any potential mobi lization of trace elem ents that may occur.

CERCLA exempts from liability, under CERCLA section 107, 42 U.S.C. 9607, certain "federally
p ermitted releases" (FPR) as defined in CE RCLA, 42 U.S.C. 9601(10). Therefore, Class VI requirements and permit s will need to be carefully structured to ensure that they do not 'authorize' inappropriate releases, and would need to prevent poten tial releases from the well which are outside the scope of the Class VI permit. Furt hermore, EPA is promulgating the GS rule under the authority of the SDWA. To the extent the commente r is seeking interpretations of CERCLA and its related provisions, such as the definition of a federally permitted release, such interpre tations are beyond the scope of this rulemaking.

The UIC program Director has authority under SD WA §1423 to address potential compliance issues (e.g., potential releases that may endanger USDWs) re sulting from injection violations in the unlikely event that a remedial response is necessary. Although EPA anticipates that the need for emergency or remedial actions at GS s ites will be rare, the GS rule require s, at §146.94, that emergency and remedial response plans be developed and updated to addre ss such events and that owners or operators demonstrate that financial res ources are set aside to implemen t the plans if necessary, per §146.85.

Regarding long term liability, once an owner or ope rator has met all regulator y requirements under Part 146 for Class VI wells and the Director has appr oved site closure pursuan t to requirements at §146.93, the owner or operator will generally no longer be s ubject to enforcement for regulatory noncompliance. Furthermore, their financial inst rument as required under §146.85 will be released if it was not used. However, even if a site closure is approved under §146.93, an owner or operator ma y be held liable for regulatory noncompliance (including violation of 40 CFR 144.12) in certain circumstances. For example, an owner or operator may be held liable for regulatory noncompliance even after site closure was approved if the Director relied on erroneous information (e.g., erroneous modeling data) provided by the owner or operator when approving site closure.

Separate from EPA's authority to enforce regulatory co mpliance, an owner or operator may be subject to a §1431 response order even after proper site closure is approved under §146.93. Under §1431 the Administrator may require an owner or operator to take necessary response measures if he or she receives information that a contaminant is present or is likely to enter a public water system or an USDW, which may present an imminent and substantia l endangerment to the heal th of persons, and the appropriate State and local authorities have not acted to protect the health of such persons. The action may include issuing administrative orders or commencing a civil action for appropriate relief against the owner or operator of a Class VI well. If the owner or operator fails to comply with the order, they may be subject to a civil penalty for each day in which such violation occurs or failure to comply continues.

Furthermore, after site closure an owner or operator may remain liable under tort and other remedies, or under other federal statutes including, but not limited to, Clean Air Act, 42 U.S.C. §§7401-7671; CERCLA, 42 U.S.C. §9601-9675; and RCRA, 42 U.S.C. §6901-6992. EPA does not have authority to transfer SDWA or other legal liabil ity for Class VI wells to the Stat e or federal government or a thirdp arty fund. See the final rule preamble for further discussion of EPA's final approach.EPA recognizes the significant amount of data generated by the DOE partners hips and agrees that sufficient data have been collected to inform the final GS rule. EPA has eval uated permits and reviewed operational data and information associated with the seven regional carbon sequestration partnerships funded by the U.S. Department of Energy and coordinated through the National Energy Technology Laboratory. EPA believes that these projects form a solid basis for finalizing the GS requirements, and agrees there is no reason to wait until all phase s of the DOE demonstration tests are complete.

Comment: Process for permit re view by experts

We recommend that EPA consider establis hing a process to collect input from experts to help inform EPA and states on evolving GS technology and appropriate
p olicy and regulatory responses. Partic ipants in the process should be independent, non-partisan, unbiased experts in the field, We recommend that the
p articipants not be convened under the Fede ral Advisory Committee Act. Their opinions would be non-binding. Obtaining such input would help regulators improve their permitting deci sions and would be complementary to the objectives of increased funding and resources for the UIC Program, outlined below.

Response: The final rule is based on the most recent GS-related data, information, and scientific research available. EPA believes th at sufficient data have been coll ected to inform the final GS rule. N evertheless, EPA anticipates that fu ture experimental and full-scale projects will continue to inform the technology, and is therefore using an adaptive rulemaking approach. EPA plans, every six years, to collect and review data on GS projects to determ ine whether the appropria te amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulat ory approach, including the discus sion of the public participation requirements, please see the final rule and preamble as well as the rulemaking docket.

Comment: Carbon sequestration is a unique type of injection undertaken for a unique and critical purpose. It is no t hydrocarbon storage nor is it industrial hazardous waste disposal. A hybrid approach should be taken in the development of rules that will facilitate the expeditious deployment of CCGS technology on a large and commercial scale. The de velopment of rules for Clas s VI CO2 injection wells should logically begin with the existing rules for Class II enhanced oil recovery (EOR) wells using CO2 thereby building on the experience of 30+ years during which these type of CO2 wells have been in operation. From this starting
p oint, CCGS rules can be tailored to account for the unique features of geologically sequestered CO2; namely la rge volumes, reactivity of CO2 in the
p resence of water, buoyancy, mobility, and extremely long time period of sequestration. Beginning with existing rule s for Class I industrial wells as a reference for the proposed rule (page 43503 of the federal register notice) sends the messa g e that in j ection of CO2 for g eolo g ic sequestration is akin to Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22286

Commenter Name: Walter L. Bake r Letter ID: 0253 Commenter Or g anization: Utah Division of Water Qualit y Comment ID: 22338industrial waste disposal rather than ma nagement of the major greenhouse gas it is.

Response: EPA clarifies that the GS rule does not promote or encourage the use of GS; rather it ensures consistency in permitting underground injection of CO2 at GS operations across the United States and
p rovide requirements to pr event endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA adds that the GS re gulation builds upon the long-standing protective framework of the UIC Program, which has been regulati ng the injection of billions of gallons of fluids for decades, including wells used for enhanced oil recovery. It includes requirements that address the unique technical criteria for permit ting GS wells that are tailored the existing UI C regulatory framework to address the unique nature of CO2 injection for GS.

Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory approach, including the discussion of how this rulemaking affect existing injection wells under the UI C Program, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1680 1.3.8 Don't overstate risk, don't stigmatize CO2 Comment: ExxonMobil has participated extensively in the preparation of the comments submitted by the American Pe troleum Institute (API) on this proposed rule and endorses their comments. We share the c oncerns raised by the API in their comments. Specific concerns are with use of the Class I UIC (Industrial/Hazardous Waste) program as the basis for the propos ed rules, the proposed prohibition of injection above the lowermost underground source of drinking water, and the
p roposed 50 year post closure monitoring period. In each of these cases, the EPA has not fully leveraged on industry's successful experience with the Class II EOR
p rogram and instead, by building on th e Class I program, is proposing requirements that are overly restrictive and could have a significant chilling effect on the commercial scale implementa tion of GS. It is our position Ihat ExxonMobil's and industry's experience with CO2 based EOR provides a sound basis from which to form an environmenta lly sound regulatory framework for GS.

Response: EPA disagrees that the GS regulation is overl y restrictive. EPA recognizes that injecting large volumes of CO2 for GS poses unique challe nges that, if not properl y managed, could endanger drinking water sources and have other adverse impacts. However, with proper site selection, the final, tailored, Class VI requirements address the large volumes of CO2 injected, its buoyancy, potential corrosivity in the presence of water, and potenti al impurities in the CO2 stream. In addition, EPA expects the tailored perm itting, siting, construction, operation, moni toring, and post-injection site care requirements in the GS rule to prevent leakage from injection formations and protect USDWs.

While EPA recognizes that industry ha s decades of experience injecting CO2 for ER, EPA believes that injection for the primary purpose of long term storage is sufficient ly different from Class II ER operations and warrants tailored requirements. Fo r example, the volume of CO2 anticipated to be injected in Class VI wells is significantly greater than for Class II wells. Reservoir pr essure conditions will also be different, with Class VI injection operations involving large volumes of CO2 and likely having higher pressures within their storag e formations than Class II ER projects.

EPA adds that the intent of the GS rule is not to pr omote CCS; rather, the purpose of the rule is to ensure Commenter Name: Ken Mille r Letter ID: 0257 Commenter Or g anization: ExxonMobil Production Compan y Comment ID: 22369that, where deployed, GS performed in a manner that protects USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 1000 1. General and Administrative Comments Comment: In conclusion, ExxonMobil is committed to working with the EPA individually and through the API and other groups to develop scientifically sound,
p erformance based regulations for the geologic storage of C02. E ach of the areas of concern we have identified are more fully addressed in API's comments.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment and API’s comment for further details. Fo r additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Comment: The NAM also supports establishment of a single and transparent regulatory structure that applies to CCS rather than a patchwork of regulatory and liability statutes that were designed to regulate activities completely unrelated to CCS. To this end, the NAM would support a continued dialogue with EPA and other regulators in order to craf t a new and modern structure specific to CCS, and established in such a manner that will expedite its deployment, while not hindering the refinement a nd improvement of the process.

Response: EPA acknowledges that GS falls within the broader context of CCS and the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordina ted with other Agency program of fices and across federal agencies (e.g., with the Department of Energy; United St ates Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Minerals Management Service; and the Bureau of Land Management). The Agen cy continues to evaluate areas of potential applicability of other Federal environmental statutes including, but not limited to: the Clean Air Act; the Resource Conservation and Recovery Act; the Comprehens ive Environmental Res ponse, Compensation, and Liability Act; and the Marine Prot ection, Research, and Sanctuaries Ac t to various aspects of GS and CCS. The Agency will continue to coordinate on GS- and CCS-related issues to minimize redundancy and maximize efficiencies for owners or operators . For additional information, please see the discussion entitled "How Does This Rulemaking Relate to Othe r Federal Authorities and GS and CCS Activities?" in the preamble to th e final GS rule.

Comment: First we stress again the importance of promulgating adequate regulations for GS in a timely fashion. GS has an important role to play in reducing carbon dioxide emissions in the U.S. and, although proj ects can be permitted under existing rules, a dedicated set of regulations is needed both to increase certainty further but also adequately to safeguard human health and the environment. Therefore, in considering whether a Noti ce of Data Availability (NODA) is needed, we urge EPA to choose the most expeditious option that is accountable, transparent, le g all y robust and defensible, and also to ensure that whichever Commenter Name: Ken Mille r Letter ID: 0257 Commenter Or g anization: ExxonMobil Production Company Comment ID: 22371

Commenter Name: Keith McCoy Letter ID: 0258 Commenter Or g anization: National Associati on of Manufacturers Comment ID: 22375

Commenter Name: Geor g e Peridas Letter ID: 0291 Commenter Or g anization: Natural Resources Defense Council Comment ID: 25285option is chosen does not delay the promulgation of the rule.

Response: EPA clarifies that the GS rule does not promote or encourage the use of GS; rather it is designed to ensure consistency in permitting underground in jection of CO2 at GS operations across the United States and provide require ments to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO 2 emissions. EPA believes that the GS regulation will provide regulatory certainty and oversight that operators ha ve requested, and allow for the deployment of this key climate change mitigation technology that could be deployed to reduce CO2 emissions.

Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory approach, please see the final ru le and preamble as well as the rulemaking docket.

Comment: The Sierra Club will be submitting comments, written comments to the EPA addressing more specifics about this type of permit. But in closing, we want to urge the EPA to look at this in a more holistic manner and not piecemeal this into just a drinking water issue. The en tire purpose of this permit, according to U.S. EPA is to keep CO2 emissi ons out of the atmosphere. Thank you.

Response: EPA acknowledges that GS falls within the broader context of CCS and the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordina ted with other Agency program of fices and across federal agencies (e.g., with the Department of Energy; United St ates Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcem ent, formerly the Minerals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applic ability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

Please see the remainder of EPA's responses to this comment and to Sierra Club's written comment for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: I wanted to make a few points this afternoon. First, I wanted to ask that the comment period be extended. These are very complicated issues for IGCC and for carbon capture and sequestration. I notice that EPA's six to nine months late in doing its due diligence on this topic and because of the complication of the
p rocess and the complication of the scien ce and of course, the public is even less able to comprehend these issues than EPA is so I am asking you today, to give us a six month extension for public comment on this. It does not seem fair to ask us to do the hustle to respond in thirt y da y s. Commenter Name: Becki Cla y born Letter ID: 0509 Commenter Or g anization: Sierra Club Comment ID: 21205

Commenter Name: Becky English Letter ID: 0524 Commenter Or g anization: Sierra Club Comment ID: 21482I was wondering if this might have been part of a pattern that some of us have noticed at EPA for some hurry up processi ng before the Bush administration runs out. Some of us frankly do not quite trus t Administrator Johnson's motives in this and we think we need to have so me time to digest this process.

Congress has been in a continuing resolution mode producing anyway and there is new information coming out as I know you are even more aware of than I am about some actual leaks of CO2 in process and these, of course, would need to be considered not only by EPA, but by the public and so I do not know if this is a discursive mode, but I want to ask you a question of process. Is my requesting this extension, does that mean it will happen or do we need to file a formal extension request?

Response: EPA acknowledges the comment. EPA did extend the comment period for the proposed rule by an additional 30 days. Please see the remainder of EPA's responses to this comment and to Sierra Club's written comment for further details. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Comment Code: 1210 1.1.1 Comments about the proposed rule



### Individual Comments

Other EPA Comment Codes and Descriptions: 1310 1.1.2.4 Comments on other "out of scope" issues, e.g., pore space ownership Comment: We believe the following issues warrant additional review by the Environmental Protection Agency:

1. The potential negative impact to larg e CO2 deep saline formation geologic sequestration projects resulting from the reference in these regulations to storage rather than disposal, implying the CO2 may have value or is even actually a commodity. Large projects could have a CO2 plume covering many square miles. The reference to storage may result in the operator having to rent or pay for the use of pore space for storage, wh ich may involve deal ing with numerous
p arties, considerable legal work and considerable costs.

2. The potential adve rse impact to Class I industr ial waste disposal well
p rogram that could result fr om the concept of storage described in above item #1.

Response: EPA acknowledges that issues such as pore space ownership and surface and subsurface
p roperty rights are important issues that need to be addressed; howev er, these are generally addressed though state regulations and are outside of the UIC program’s authority under the Safe Drinking Water Act (SDWA). EPA adds that the requirements appl y to owners or operators of in j ection wells used to Commenter Name: Michael H. Cochran Letter ID: 0108 Commenter Or g anization: Bureau of Water, Division of Environment, Kansas Department of Health & Environment (KDHE) Comment ID: 21942inject CO2 for permanent storage, and do not apply to owners or opera tors of Class I wells.

EPA believes that developing a consistent regulatory framework will ensure that there is adequate opportunity for public involvement on the permitting process and that all US DWs are protected from endangerment.

Comment: Dialogue between the Regulated and Regulat or Isn’t Obvious Th e draft Class VI rule and especially the preamble assert numerous times that a key to ensuring the safety and efficacy of geologic seque stration is a well functioning dialogue between the regulated entity and the re gulatory agency. There are at least three intertwined concerns I have with the way the current draft Class VI rule is written that if left unresolved woul d hamper a robust, meaningful dialogue between the regulated entity and the regul ator has been created by this rule.

1) The concept that there is "working" relationship between the permitee and the
p ermit-granting agency doesn’t really come through here. This seems like a very arms length relationship.

2) The draft rule never esta blishes that the process of moving from initial site selection to permitting, to op erations to renewal of pe rmits to closure is an iterative one between the operator and the EP A or state permit writer (acting as stewards of the public’s welfare) as ne w data are generated and incorporated into the site management plan. That is, the rule could do a much better job of explaining that the permittee and the regulator should be learning a great deal about how a particular geostorage field is operating in practice and that this knowledge will be factored into how th e field is regulated in the future (including decisions about post closure).

3) Data is collected but it is not clear how it is used by the regulator nor is it clear who has access to this data. In particular, there appears to be only two instances (one at the very earliest st ages of site selection and the other before site closure) where the public is invited to learn and comment on a GS
p roject.

Given that humanity is in the early days /decades of CCS deployment, it seems to me that much could be learned by having closer and more frequent communication between the regulator and ow ner/operator of a GS project , and allowing for some dissemination of the massive amount of data generated by these projects. A more transparent and meaningful dialogue betwee n these two parties would also help with stakeholder acceptance of CCS.

Response: EPA agrees that communication and coordi nation between owners or operators and
p ermitting authorities are important. The GS rule incorporates a flexible approach, where operators of GS projects develop and implemen t site-specific plans for delineat ing the AoR, performing corrective action, testing and monitoring, and post- injection site care. EPA believes that the plans—which will be reviewed and approved by the Director and periodi cally updated throughout the life of the project—
p romote an on g oin g dialo g ue between the operator and the Director that will encoura g e use of the most Commenter Name: James Doole y Letter ID: 0156 Commenter Or g anization: Joint Global Change Research Institute, Pacific N orthwest National Laborator y Comment ID: 22643appropriate technologies for a partic ular project and that GS projects are permitted sited, constructed, operated, and closed in a manner that avoids releases of CO2 into USDWs.

EPA is developing a number of technical guidances a nd implementation materials to assist owners or operators and Directors in the permitting process. These guidances will address how to perform many of the activities necessary for applying for a permit, including developing all required plans and conducting site characterizations that meet the requirements of §146.82. The guidances will be available on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm

Comment: Who has access to reports on an ongoing GS project?

o Page 43517. It is asserted that the requirement for "monitoring, testing, AOR, and corrective action" plans will help establish "an ongoing dialogue between the operator and th e permitting authority." This reviewer just doesn’t see this "dialogue" in this rule. There is no discussion of how these plans are used and therefore this looks like a very distant and at arms length process. I am 100% in support of there being an ongoi ng dialogue between the operator and the regulator and I believe that these a dditional plans are a wise requirement for Class VI GS wells.

Response: EPA believes that the plans site-specific plan s for delineating the AoR, performing corrective action, testing and monitoring, and pos t-injection site care —which will be reviewed and approved by the Director and periodically updated throughout the life of the project—promote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project and that GS proj ects are permitted sited, constructe d, operated, and closed in a manner that avoids releases of CO2 into USDWs.

EPA is developing a number of technical guidances a nd implementation materials to assist owners or operators and Directors, including a guidance that describes recommended approaches for developing, reviewing, and updating the GS project plans. The gui dances will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Comment: - Page 43497. To the extent that EPA will revise this preamble language, please consider ending the section on "Potential USDW Impacts" with a new sentence that reaffirms that the purpose of this proposed rule is to put in place regulations, best practices, enforcement mechanisms, etc. to ensure that all of the
p reviously mentioned bad things that c ould go wrong with a CO2 storage project do not take place. This reviewer thinks that given the negative tone of much of the material in this section it is appr opriate for the USEPA to reinforce the
p oint that the purpose of this rule is to ensure that CO2 storage is done safely thus significantly reducing if not eliminating the extent to which any of these things actually happen. Commenter Name: James Dooley Letter ID: 0156 Commenter Or g anization: Joint Global Change Research Institute, Pacific N orthwest National Laborator y Comment ID: 22649

Commenter Name: James Dooley Letter ID: 0156 Commenter Or g anization: Joint Global Change Research Institute, Pacific N orthwest National Laboratory Comment ID: 22655- Page 43495 under "Why is Geologic Sequest ration Under Consideration". Please change sentence which says in part "he cap ture and storage of CO2 would enable the continued use of coal in a manner that" The first deployments of CCS are not going to be at coal fired electric power plants. There is no reason for this rule to be overly focused on coal based CCS applications and is not appropriate for this Class VI UIC rule since it is bounded by the SDWA which means that the source of CO2 is not a crit ical aspect of this rule. Focusing on coal can also bring in a lot of ancillary (although important) issues surrounding the use of coal like mining practices that do not need to be discussed within the boundarie s of a proposed Class VI UIC rule. CCS is more than just coal.

Response: EPA clarifies that the intent of the Class VI GS requirements are designed to ensure that, where deployed, GS is conducted in a manner that protects USDWs from endangerment. Please see the final rule and preamble for additional information on EPA's final approach.

Comment: establishment of the new Class VI well category for CO2 injection but advises EPA not to adapt more restrictions on it than found in the Class I hazardous waste wells. Many of the construction, mechanical integrity, monitoring and financial assurance provisions for Class VI are more comprehensive and more strict that those for Cla ss I. EEI comments on the topic suggest: "EPA should avoid risk management approaches that discourage CCS deployment or create additional uncertainty, and to seek where possible to br ing greater certainty to the long term obligations and risks associated with a GS project. " As a

Response: EPA disagrees that the requirements in the GS rule are overly stringent. The Agency believes that all of the requirements for GS wells are necessary to ensure that GS is conducted in a manner that protect s USDWs from endangerment.

EPA developed the Class VI regul ations in recognition that the risks posed by GS to USDWs are fundamentally different than those associated with current injection practices regulated by the UIC
p rogram, including Class I hazardous waste injection wells. For example, CO2 is more buoyant, less viscous (i.e., more mobile), and in some cases more corrosive than fluids injected into Class I hazardous waste wells. In addition, the large in jection volumes anticipated for GS wi ll likely be much greater than current injection practices. Lastly, CO2 movement in the subsurface is not as well understood as fluids currently injected under the Class I program.

Please see the remainder of EPA’s responses to this comment for further detail s related to construction, mechanical integrity, monitoring and financ ial responsibility fo r Class VI wells.

Comment: DIRECTOR DISCRETION

USWAG advises; "While dire ctorial discretion is a usef ul mechanism to ensure flexibility in the Final Rule, such di scretion must be clearly defined and limited." DTE Ener gy endorses this comment and also acknowled g es that we have Commenter Name: Skiles Bo yd Letter ID: 0160 Commenter Or g anization: DTE Ener gy Comment ID: 21274

Commenter Name: Skiles Bo yd Letter ID: 0160 Commenter Or g anization: DTE Energy Comment ID: 21276had reasonable interactions with our state and regional regulators on other UIC wells. We do recognize this is one mechanism to ensure that needed flexibility but there should be some boundaries and limitations as to the extent of discretion provided the Director.

Response: EPA is developing guidances fo r States that describe the process of appl ying for and receiving primary enforcement au thority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum fede ral criteria and requirements. The guidan ce will describe ar eas of Directorial discretion and considerations for how that discretion would be exercise d. This guidance will be available on EPA’s website at http://w ater.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Comment: API has serious concerns with several se ctions of the proposed rule, including the lowermost USDW restriction, the 50-year post-injection site care requirement, the well c onstruction and operation requirements and the definitions of Geological Sequestration Pr oject and Area of Re view which we ddress below. API also offers detailed revisions to address these issues and

Response: EPA acknowledges the comment. Pl ease see the remainder of EPA' s responses to this letter for further details.

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: API offers many technical clarifications to the rule based on industry's experience with well design, construc tion, and operation. Some are minor clarifications but others are important revisions. For example, EPA is proposing the use of down-hole shut-o ff valves (see proposed §146.88(e) at 73 FR 43539), saying they would "isolate the injectate below USDWs, rather than just below the surface" (73 FR 43511) when in fact, down-hole shut-off valves would not actually address this concern since they ar e not designed to provi de the type of isolation envisioned by the EPA.

Response: After evaluating the risks and benefits of down-hole shut-off systems and considering additional research, EPA will not require automa tic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells install automatic surface shut-off devices. The rule afford s Director's discretion to mandate automatic downhole shut-off devices in onshore situations that may warrant their use. However, the Agency believes that offshore Class VI wells pres ent unique construction and operati onal conditions, including isolation from shorelines and the need to construct wells through the water column and the subsurface, which may delay response time in the event of well difficult ies. The rule requires, at §146.88(e)(3), that owners or operators of offshore wells wi thin State territorial waters in stall automatic down-hole shut-off systems. EPA believes that these requirements at §146.88(e) ensure that proper precautions are taken to
p revent subsurface fluid movement and ensure protection of USDWs. Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24118

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24119EPA clarifies that down-hole shut-o ff devices are currently used in situations where loss of well integrity could result in damage to the well or harm to humans (e.g., near high-density population areas, or in onshore acid gas injection; IEA, 2003). EPA has identified examples of documented logging techniques, including ultrasonic and temperature logs, that can be pe rformed with an automatic downhole device emplaced (Julian et al ., 2007; Somaschini et al., 2009). They are also used in high pressure, high temperature onshore wells a nd in permafrost areas.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: EPA should be aware that some provisi ons seem to be based on data and information that would actually be generated by the permitted activity and therefore would not be available at th e time of submittal of the permit application. For example §146.82(c) request s data from wells that cannot be drilled until the permit is received. EPA proposed rules appear to contemplate delineation and evaluation ac tivities prior to submitta l of an application for GS wells/projects. It is not clear to API under what author ity and regulatory framework these activities would be conducte d since most Class VI projects will not be oil and gas related and so woul d not fall under oil and gas rules.

Response: EPA agrees that not all of the information li sted at §146.82 of the proposed regulation will be available at the time the owner or operator develops their initial permit a pplication. In response to comments and based on an evaluation of the proposed requirements at §146.82, the Agency revised this subpart so that the final regulation specifies separate requirements for information to be submitted with the permit application and before well construc tion is approved (at §146.82(a)) and information to be submitted before operation of the we ll is authorized (at §146.82(c)).

EPA believes that this revision of §146.82 addresse s commenters' concerns regarding the timing of information to be submitted. In addition, section §146.82 in the final rule is similar to the permit application requirements for other in jection well classes, which could help avoid confusion about how to meet the permitting requirements fo r Class VI wells. The requirements at §146.82(c) for information to be submitted before operation of the well is authorized are very simila r to those for Class I wells, with modifications and additions that a ddress the unique challenges and types of data collected for GS wells.

Comment: Monitoring, Corrective Action, Record Keeping, and Long-Term Liability

Guidelines Needed:

It would be helpful if additional guidelines were included in the rule to
p rovide state regulatory authorities with the ability to determine requirements for monitoring, corrective action, record keeping, a nd liability of carbon sequestration injection well sites. Guid elines are needed to help states consider baseline geochemical analysis and monitoring data, as well as corrective action plans, in the event that a USDW becomes affected by an in

j ection well site. Guidelines are also needed to ensure that the lon g -term Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24120

Commenter Name: James Taft Letter ID: 0172 Commenter Or g anization: Association of State Drinki ng Water Administrators (ASDWA) Comment ID: 23455financial responsibility of owners/operato rs of injection wells adequately cover the potential costs of site closure and stewardship. While the rule should
p rovide some minimum requirements for re cord keeping and the frequency of reporting, the rule should also be flexible enough to allow states to address site-specific conditions in determining these requireme nts. Common assumptions will need to be tested under the unique conditions of individual sites in order to avoid unintende d consequences.

Response: EPA believes that the Class VI requirements balance site-specific fl exibility with USDW
p rotection. Rather than setting performance or t echnology-based standards for GS projects, EPA is adopting a flexible approach, where operators of GS projec ts would develop and im plement site-specific
p lans for delineating the AoR, te sting and monitoring the site, pe rforming corrective action, and postinjection site care. EPA believes that the plans—wh ich would be reviewed a nd approved by the Director and periodically updated throughout th e life of the project—promot e an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a particular
p roject.

EPA is developing guidances for States that descri be the process of applyi ng for and receiving primary enforcement authority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum federal criteria and requirements. The guidance will describe area s of Directorial discretion and considerations for how that discretion would be exercised. This guidance wi ll be available on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm.

Other EPA Comment Codes and Descriptions: 3140 2.1.4 Comments that the proposed geologic data requirements are too stringent Comment: • In many instances the proposed require ments for Class VI CO2 GS wells are unnecessarily more stringent than existi ng requirements for other well classes under the UIC Program. While it is essentia l that the Final Rule be protective of underground sources of drinking water ("USDWs"), many of the more rigorous requirements proposed for Clas s VI wells are not warran ted by findings of unique risks posed by CO2 GS wells. The Final Rule should craft requirements that
p rotect USDWs while avoiding the impositi on of unnecessary costs or the creation of an unfounded negative public pe rception of CO2 GS projects.

Response: EPA disagrees that the requirements at §146.82 are too stringent and believ es that a detailed geological site characterization is essential to evaluating the presence and adequacy of the various geologic features necessary to re ceive and confine injected CO2 for GS. The requirements for geologic site characterization are based on a long standing UIC regulatory framework developed to address specific risks to USDWs posed by injection. The Class VI GS requirements are tail ored so that they are appropriate for the unique nature of injecting la rge volumes of CO2 into a variety of geological formations for long-term storage.

The mission of the UIC program and the goal of the GS regulation is to protect USDWs from endangerment, and every aspect of the GS rule is designed toward that end. Therefore, EPA disagrees that any of these protective requirements are unn ecessary, and clarifies that waiving any of the requirements would not be acceptable. The GS regulation allows flexibility where appropriate. Certain requirements (e. g ., the need to characterize additional confinin g la y ers) are at the Director's discretion Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utilit y Solid Waste Activities Group (USWAG) Comment ID: 23460(§146.83(b)), based on his or her understanding of a particular site.

EPA disagrees that the requirements would negative ly affect public percepti on of CO2 GS projects. Rather, EPA believes that a demonstration to the publ ic that extensive data have been collected and evaluated would likely improve confidence in th e project and help address public questions and

concerns.

Other EPA Comment Codes and Descriptions: 2020 1.5.1 Support Class VI designation Comment: The proposed Federal requirements under th e Safe Drinking Wate r Act (SDWA) for underground injection of carbon dioxi de for the purpose of geologic sequestration is a step forward. SSEB suppor ts the establishment of a new Class VI designation specifically dealing with GS. A new class of wells with minimum technical criteria for the geologic site characterization, fluid movement, area of review (AoR) and corrective action, we ll construction, operation, mechanical integrity testing, monitoring, well plugging, post-injecti on site care, and site closure for the purposes of protecting USDWs will advance GS projects. The
p roposed rule will help to ensure consistency in permitting of underground injection of CO2 at GS operations across the Unit ed States and provide requirements to prevent endangerment of US DWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA’s regulatory provisions should accurately reflect the low risk profil e that exists for CO2 exposure from a GS project.

Response: EPA agrees that tailored requirements for Cla ss VI wells are necessary to address the unique nature of injecting large volumes of CO2 and to en sure that USDWs are protected from endangerment. The GS rule contains tailored requirements for the permitting, geologic site characterization, AoR and corrective action, well construc tion, operation, mechanical integrit y testing, monitoring, well plugging,
p ost-injection site care, and site closure of GS wells that directly addr ess issues unique to the nature of large-scale CO2 injection for GS.

Comment: Site-Specific Approach

Policy regarding GS siting should reflect that conditions affecting risk differ by site and should be tailored to ri sks presented by specific sites. For example, CO2 has been injected undergr ound for several decades for EOR. This technique is well developed and there is now a history through which its risks can be assessed. This differs from inje ction for long-term storage in deep saline formations or unmineable coal seams, with which there is limited experience, particularly on the massive scal e -- a million or more tons per year
p er site -- envisioned for the future. Poli cy must encourage development of new data, technology, and practices while re cognizing that existing technology is readily applicable. It also should refl ect that some long term injection
p ractices such as natural gas storage and EOR already are known to pose little risk. Sites also will differ based on reservoir and confinement geological details, proximity to USDWs and other res ources, and other factors. In addition, Commenter Name: Kenneth Nemeth Letter ID: 0176 Commenter Or g anization: Southern States Ener gy Boar d Comment ID: 23535

Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23801Response: EPA agrees that permitting deci sions for GS wells should be ba sed on site-specific factors. The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable fo r GS. Additionally, many of the permit requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testing and monitoring, and injec tion well plugging and post- injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Dir ectorial discretion. The Agency believ es this balance allows for GS
p rojects to be designed and permitted to address the unique, site-specific aspects of each project, while
p roviding consistency in permitting across the U.S.

EPA adds that the GS rule does not categorically pr eclude injection of CO2 into any formation types. The purpose of the GS rule is to ensure protection of USDWs from endangerment, and the rule requires that owners or operators demonstrat e that wells are sited in suitable systems with geologic formations to receive and confine injected CO2, re quired at §146.83 of the GS rule.

Other EPA Comment Codes and Descriptions: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 Comment: The ELPC’s primary objection to the propos ed regulation is that regulation of geologic sequestration under the SDWA is too narrow in focus to ensure that carbon capture and sequestration ("CCS") fu lfills its potential to be "a key mitigation technology for achieving dom estic [greenhouse gas] emissions reductions." 73 Fed. Reg. at 43,496. EPA is proposing to regulate GS by creating a new category of injection well ("Class VI") for GS under its existing UIC program under the SDWA. As EPA ac knowledges, however, its authority under the SDWA is limited. See 42 U.S.C. 300h(a)-(b)(1) , (d); 73 Fed. Reg. at 43,495. Other rules and regulations are needed to address CCS issues falling outside the scope of the SDWA (e.g., establishing m echanisms for protecting private drinking water supplies, funding costs and damages associated with injury to persons and/or water supplies despite compliance with the UIC regulations, accidental releases of CO2 to the atmosphere, and compensation for and remediation of harm to public health or the environment other than the endangerment of underground sources of drinking water ("USDWs")). Se e infra Part III(c)(1)(b); 73 Fed. Reg. at 43,495, 43,497, 43,520, 43,522 (discussing EPA’s view of CCS issues that fall outside purview of SDWA). Other issues related to the capture and transport of CO2 also need to be considered and addressed.

Many of these issues are of critical importance and will li kely need to be addressed before large-scal e industry investment in CCS will take place. See, e.g., infra Part III(C)(1)(b )(ii) (discussing industry’s need for a clear and comprehensive long-term liability sche me). Piecemeal regulation of CCS is likely to cause confusion, inefficiency, potentially conflicting requirements or
p olicies, and other problems that could be avoided by a comprehensive approach to regulation of CCS. Alt hough ELPC and ETIP believe comprehensive regulations addressing CCS would more likely ensure that CCS becomes a successful climate change mitigation technology , we recognize that Congress may need to enact legislation enabling EPA (or another federal agency) to take such a comprehensive approach. Commenter Name: Wend y Jacobs Letter ID: 0183 Commenter Or g anization: Harvard Law School Environmental Law and Policy Cente r Comment ID: 25137Response: EPA received a number of comments indicati ng that the Agency should further explore environmental and regulatory issues beyond the scope of the GS rule as proposed. This comment is outside the scope of this rulemaking.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

Other EPA Comment Codes and Descriptions: 3800 2.3 Proposed Injection Well Construction Requirements ( 40 CFR 146.86) Comment: ELPC and ETIP commend EPA for including precautionary measures for Class VI wells above and beyond what is require d for other classes of wells. The
p roposed regulation allows the owner or operator the flexibility to choose
p articular cements or metal well components for Class VI wells while still requiring that such materials meet or exceed the standards developed by the American Petroleum Institute, ASTM In ternational or comparable standards acceptable to the Director. 73 Fed. Reg. at 43,537 (proposed 40 C.F.R. § 146.86(b)(1)). By doing so, the proposed regulation addresses the potential corrosion of cement and metal well co mponents by the CO2 stream (plus water impurities) that can compromise the struct ure of the well and result in leaks of stored CO2. ELPC and ETIP laud other pr ecautionary measures required in the
p roposed regulation, including down-hole shut off valves, continuous and frequent monitoring of the integrity of the internal and external portions of the well, tracking the plume and pressure front, and detailed electronic record keeping. Id. at 43,511, 43,538-40 (proposed 40 C.F.R. §§ 146.88-.91). The requirements in the proposed regulati on reflect EPA’s understanding of and sensitivity to the challenges posed by CCS. Because CO2 GS entails new technology with a potentially large imp act and lasting duration, ELPC and ETIP support these precautionary measures.

Response: EPA acknowledges the comment and agrees that protection of USDWs from endangerment and prevention of fluid movement between format ions is paramount. Appropriately designed and constructed wells are necessary to prevent endangerment to USDWs and maintain integrity of the well throughout the lifetime of a GS project. This is the foundation of the requirements for construction and
p re-operational testing of Cl ass VI wells at §§146.86 and 146.87. Commenter Name: Wend y Jacobs Letter ID: 0183 Commenter Or g anization: Harvard Law School Environmental Law and Policy Cente r Comment ID: 25139Please see the remainder of EPA's responses to this comment and the final rule and preamble for further details.

Other EPA Comment Codes and Descriptions: 1250 1.1.1.4 Flexibility is needed (performance- b ased standards); 1420 1.2.1.1 Support the GS rulemaking Comment: Protection of U.S. Drinking Water (USDW) sources is paramount and a central requirement of the Safe Dr inking Water Act and ConocoP hillips wholeheartedly supports high standards for protection of cu rrent and potential future USDWs. We believe that maintaining focus on several key principles can ensure rulemaking that is protective and flexible to allo w site specific considerations while maintaining cost-effective operations. We applaud EPA's work to that end. We support most concepts, elements and deta ils in the proposed requirements, and
p rovide our comments to reinforce and amplify a few issues which we believe flow from the following importa nt key principles:

o All UIC well classes have requirement s fully designed to protect USDW's.

o The oil and gas industry's experience with CO2 injection for enhanced oil recovery (EOR) provides a track record of USDW protection that can enhance EPA's rulemaking.

Response: EPA believes that the creation of a new in jection well class (V I) under the existing UIC Program is necessary to enable the use of GS as a climate change mitigation technology in a manner that
p rotects USDWs from endangerment. EPA agrees th at the UIC Program, under the authority of the SDWA, provides a strong framework for regulating injection of CO2 for GS and adds that the GS regulation tailors the UIC requirements to address the unique issues associated with large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurit ies in captured CO2, and its mobili ty within subsurface geologic formations.

EPA recognizes that the oi l and gas industry has decades of experi ence injecting CO2 for the purpose of ER, and that sites used for ER may be suitable for GS and may be among the first GS sites. Some of the research that informs the final GS rule was conducted at ER sites. EPA also recognizes that a by-product of ER activities is that a certain percentage of the CO2 is trapped in the receiving formation.

Other EPA Comment Codes and Descriptions: 1260 1.1.1.5 More certainty/stringency is needed Comment: Issue 2. Under the proposed rule, full-s cale implementation can begin after finalization.

The EPA is encouraged to consider limi ting the scale of projects initially in order to identify issues that may crop up that are currently unanticipated. The early large scale projects should be extens ively monitored in order to validate concepts that can be applied to other lo cations. This early work should include validation of appropriate modeling techniques capable of reliably predicting

s y stem responses. This earl y proof of concept work shoul d also address issues of Commenter Name: Jeff W. Sheets Letter ID: 0192 Commenter Or g anization: ConocoPhillips Comment ID: 23887

Commenter Name: Andy Horn Letter ID: 0196 Commenter Or g anization: Colorado Ground Water Association (CGWA) Comment ID: 23922heterogeneity in reservoi r and confining zones.

Response: EPA clarifies that the intent of the GS rule is not to set or control the pace at which GS is deployed. Rather, the purpose of the GS regulation is to ensure that GS, where deployed, is conducted in a manner that protects USDWs from endangerment. The Class VI GS requirements are one way in which the Agency can achieve this goal. EPA does not intend to limit the scale of initial GS projects; each project will be eval uated based on site-specific informati on about the ability of the geologic formations to safely receive and confine injected CO2. However, the Agency agrees that a protective initial approach is appropriate and additional safegua rds are necessary, given the uncertainty associated with the long-term effects of CO2 GS. EPA plans, ev ery six years, to collect and review data on GS
p rojects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: 12. EPA’s implied 2017 date for completion of the final UIC regulations is too late to provide regulatory clarity faced by CCS project developers today. These are the details supporting these c oncerns and recommendations:

Response: EPA believes that sufficient data have been collected to inform the final GS rule. In addition to laboratory studi es and modeling re search that provide re levant information on GS, the Agency is also collecting and analyzing GS project data and permit information from a va riety of sources. Most notably, EPA has evaluated permits and reviewed operational data and information associated with the seven regional carbon sequestrati on partnerships funded by the U.S. Department of Energy and coordinated through the National Energy Technology Labor atory. EPA believes that these projects form a solid basis for finalizing the GS requirements, and there is no reason to wait until all phases of the DOE demonstration tests are complete . Nevertheless, EPA anticipates thatfuture experimental and fullscale projects will continue to inform the technol ogy, and is therefore using an adaptive rulemaking approach. EPA plans, every six years, to collect and review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appr opriate or necessary. EP A believes that the completion of the DOE pilots in 2017 will allow the in corporation of results of these projects into the first review of the rule.

Comment: Concern #12: EPA’s schedule for promulga tion of its proposed UIC regulation. (Page 43499 Sec. E3)

We reference the following statement from the preamble section of the proposed rule: "During the Deployment Phase (2008- 2017), the [RCSP] partnerships will conduct large volume carbon storage tests to demonstrate that large-scale CO2 injection and storage can be achieved safe ly and economically. EPA will use the data collected from these projects to s upport decisions in the final GS rule." This statement suggests that a final GS rule may not be issued until 2017. We believe that this is too late to clear the regulatory uncertainty that CCS
p roject developers are facing today. If this reflects EPA’s intention, we recommend that EPA abandon a prescrip tive approach and instead, favor g eneral Commenter Name: Richard Guinn Letter ID: 0210 Commenter Or g anization: Eastman Chemical Compan y Comment ID: 22703

Commenter Name: Richard Guinn Letter ID: 0210 Commenter Or g anization: Eastman Chemical Compan y Comment ID: 22718and performance- b ased requirements until thes e demonstration tests are completed. Other concerns expressed by our membership and recommendations for improvement of the proposed rulemaking are given in Appendix A. Should the EPA have further questions, please fell free to contact me.

Response: EPA believes that sufficient data have been collected to inform the final GS rule. In addition to laboratory studi es and modeling re search that provide re levant information on GS, the Agency is also collecting and analyzing GS project data and permit information from a va riety of sources. Most notably, EPA has evaluated permits and reviewed operational data and information associated with the seven regional carbon sequestrati on partnerships funded by the U.S. Department of Energy and coordinated through the National Energy Technology Labor atory. EPA believes that these projects form a solid basis for finalizing the GS requirements, and there is no reason to wait until all phases of the DOE demonstration tests are complete . Nevertheless, EPA anticipates thatfuture experimental and fullscale projects will continue to inform the technol ogy, and is therefore using an adaptive rulemaking approach. EPA plans, every six years, to collect and review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appr opriate or necessary. EP A believes that the completion of the DOE pilots in 2017 will allow the in corporation of results of these projects into the first review of the rule.

Other EPA Comment Codes and Descriptions: 2064 1.5.3.2 Grandfathering construction of Class II wells (seeking comment) Comment: C. The Proposed Class VI Requirements Are Fa r More Burdensome than Necessary to Protect USDWs.

As the preamble acknowledges, the actual human health and ecological risks associated with GS are relatively remo te and can be addressed effectively through measures implemented to protect USDWs. 73 Fed. Reg. at 43497-98. Unfortunately, the proposed rule seems to proceed from the premise that the strictest UIC regulations in existence - those for hazardous waste injection - should serve as the starting point for the development of the Class VI regulations. Given the vast knowledge a nd experience developed through the handling of CO2 in different operations, SEPCo contends that the more logical starting point for development of the Class VI regulations is the Class II regulations.

As the proposed rule recognizes, CO2 in jection operations have been conducted
p ursuant to the Class II regulations fo r many years, and experience with thousands of wells injecting hundreds of millions of tons of CO2 demonstrates that the Class II regulations - as applied to CO2 inje ction - are adequate to
p rotect USDWs This is certainly true wi th respect to the basic construction, operating, monitoring, and mechanical in tegrity testing re quirements for injection wells; we believe that what "w orks" in terms of the construction and operation of a CO2 injection well does not depend on the purpose for which CO2 is being injected.

Unfortunately, the proposed Class VI requi rements are far more stringent than the Class II requirements, a fact that g ives rise - under the proposed rule - to Commenter Name: John Kin g Letter ID: 0211 Commenter Or g anization: Shell Exploration and Production Compan y (SEPCo) Comment ID: 22759the need to "grandfather" Class II CO2 injection wells that remain in service for GS purposes after oil or gas production has ceased. Rather than resembling the Class II requirements, the proposed Cl ass VI requirements are as stringent as those for hazardous waste injection in most respects. Indeed, many of the construction, mechanical integrity, and monitoring and financial assurance requirements proposed for Cl ass VI wells are even mo re comprehensive and stricter than those for hazardous waste in jection wells. While some of these more burdensome requirements are legitimately related to concerns about the mobility of CO2 or the an ticipated scale of GS opera tions, many - as discussed in Part III of thes e comments - are not.

Recommendation:

The Class VI requirements addressing issues such as well construction and mechanical integrity testing should be no different than the Class II requirements.

Response: EPA agrees that many Class I, Class II, and Class V experimental technology wells are designed and constructed to withstand exposure to CO 2. The final GS rule provides for the construction of these wells to be grandfathe red per §146.81(c), provided the owner or operator can demonstrate to the Director that the wells were engineered and constructed to meet the requirements at §146.86(a) and ensure protection of USDWs, in lieu of requirements at §146.86(b) and §146.87(a).

EPA disagrees that other requirements (e.g., MITs, siting, monitoring, operational, and AoR requirements) should also be grandf athered. Following re-per mitting of the well as Class VI, many of the unique factors of GS s ites (e.g., increased reservoi r pressures associated with large volumes of stored CO2 and the corrosivity of CO2 in the presence of wa ter) will result in an increased risk profile, warranting the specific requirements in the final GS rule. Therefore, fo llowing re-permitting as Class VI wells, these projects must be subject to the operational, MIT, monitoring, reporting, plugging, and postinjection site care and site closure requirements in the final GS rule. See the discussion of EPA's final regulatory approach in the preamble to the GS ru le for additional detail on these requirements.

Other EPA Comment Codes and Descriptions: 1680 1.3.8 Don't overstate risk, don't stigmatize CO2 Comment: - In many instances the proposed requireme nts for Class VI CO2 GS wells are unnecessarily more stringent than existi ng requirements for other well classes under the UIC Program. While it is essentia l that the Final Rule be protective of USDWs, many of the more rigorous requi rements proposed for Class VI wells are not warranted by findings of unique risks pos ed by CO2 GS wells. The Final Rule should craft requirements that protect USDWs while avoiding the imposition of unnecessary costs or the inappropriate cr eation of a negative public perception of CO2 GS projects.

Response: EPA disagrees that the GS regulation overstates the risk of CO2 injection or that it is unnecessarily stringent. EPA recognizes that inject ing large volumes of CO2 for GS poses unique challenges that, if not properly managed, could enda nger drinking water sources and have other adverse impacts. However, with proper site selection, the fina l, tailored, Class VI requi rements address the large volumes of CO2 injected, its buoyanc y, potential corrosivity in the presence of water, and potential impurities in the CO2 stream. In addition, EPA expects the tailored permittin g , sitin g , construction, Commenter Name: Paul L. Carpinone Letter ID: 0212 Commenter Or g anization: Tampa Electric Compan y Comment ID: 22904operation, monitoring, and post-injecti on site care requirements in the GS rule to prevent leakage from injection formations and protect USDWs.

EPA does not believe that the tailor ed requirements will create a negati ve public perception of GS. The Agency believes that a demonstration to the public th at GS projects are meeti ng the GS rule's tailored requirements will likely improve confidence in the project and help address public questions and

concerns.

Comment: AMWA also recommends that EPA commit to update the rule regularly as more becomes known about CCS tec hnology and the behavior of CO2 injected into the subsurface. AMWA recommends that EPA work to update the rule every three to five years for the foreseeable future, as this technology will become more prevalent and injection methods and other sequestra tion techniques will likely improve. In developing this proposal, EPA has demonstrated its ability to quickly bring staff up to speed on this technology and AMWA believes the Agency must continue chnological advances.

Response: EPA agrees that an adaptive approach to th e UIC GS rulemaking is appropriate. The Agency will use such an approach to ensure that US DWs are protected from endangerment and meet the
p otentially fast pace of GS deployment. EPA believes that an adaptive approach will allow regulatory development to proceed in time to meet the current and future demand for Class VI permits while recognizing the need to: continue to gather data from pilo t projects and other re search as it becomes available; and to enhance understanding of the techni cal and administrative as pects of GS deployment, operation, and technology developments. EPA plans, every six years, to collect and review data on GS
p rojects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: I. INTRODUCTION -- AND A SUGGESTED COMPLEMENTARY APPROACH

The Proposed Rule is appropriately viewed as part of EPA’s broader effort to address atmospheric emissions of CO2 a nd other greenhouse gases ("GHG").[FN1] Analysts worldwide have identified car bon capture and storage "CCS" as one of the essential components of any succe ssful strategy for lowering such emissions.[FN2] Within this broader cont ext the Proposed Rule is thus intended to encourage the safe and effective development of geologic storage or sequestration of CO2 which is in addition to existing injection and incidental storage of CO2 in enhanced oil or gas recovery opera tions ("EOR" or "EGR," respectively)) through Class II wells. In many respects, the Proposed Rule appears well-suited to advance that objective and EPA deserves credit for having developed a comprehensive approach to a complex set of issues. In other respects, however, the Propose d Rule appears to misapprehend certain core facts relating to the physical properties and behavior of CO2 in some underground formations, the scale of existin g CO2 stora g e operations incidental to EOR Commenter Name: Diane VanDe Hei Letter ID: 0213 Commenter Or g anization: Association of Metropolitan Water Agencies (AMWA) Comment ID: 22955

Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24271operations over the last four decades, and the practical fruits of that experience.

As a result, the Proposed Rule includes a number of requirements that long experience has shown are unnecessary for the protection of u nderground sources of drinking water ("USDWs") and a few th at would even prove counterproductive.

[1] See generally Regulati ng Greenhouse Gas Emissions U nder the Clean Air Act, Advanced Notice of Proposed Rulema king, EPA-HQ-OAR-2008-0318, 73 Fed. Reg. 44,354, 44,397-44,440 (July 30, 2008) (discussing CO2 emission issues under the Clean Air Act and generall y soliciting public comment on how to respond to the U.S. Supreme Court’s decision in Massachus etts v. EPA, 549 U.S. 497, 127 S. Ct. 1438 (2007) .

[2] See, e.g., Intergovernmental Panel on Climate Change, Special Report on Carbon Dioxide Capture and Storage, 208 (B ert, Metz, et al., eds., 2005) (at 13, 45) ("IPCC Special Report on CCS") (showi ng potential contribution of CCS in reducing emissions).

Response: EPA disagrees that any of the requirements in the GS rule are unnecessary. Rather, the GS regulation tailors the UIC requirements to address the unique issues associated with large-scale GS, including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurit ies in captured CO2, and its mobili ty within subsurface geologic formations.

The Agency agrees that GS is a key climate change mitigation technology that is part of a portfolio of options that could be deployed to reduce CO2 emissions. Other options include efficiency improvements and the use of alternative fuels and renewable ener gy sources. EPA clarifies that the purpose of the GS regulation is to ensure that GS is conducted in a manner that protects US DWs from endangerment and only applies to owners or operators of wells injecting CO2 for th e purpose of long-term storage.

Please see the remainder of EPA's responses to this comment and the final rule and preamble for further details.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: In addition, the Proposed Rule appears to view CO2 inject ion activity as a static activity in which CO 2 is injected one time and never leaves the storage formation. In contrast, actual experience since 1972 reveals a far more dynamic
p rocess in which individual wells may serve as CO2 injection wells, production wells producing oil and/or CO2, or indeed multiple use wells (i.e., injection of CO2, injection of brine, brine disposal , and production). The locational value of injected CO2 is likely to vary over ti me as energy and CO2 markets evolve and it may well become valuable for a Class II EOR well to transition from Class II to Class VI and then to return to Clas s II EOR activity. The Proposed Rules do not seem well suited to deal with such dynamic changes in the various interrelated markets for CO2, oil and natural gas. Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24272Response: EPA clarifies that the Class VI requirements in the GS rule are for CO2 injection for longterm storage of large vol umes of CO2. EPA acknowledges that mult iple wells may interact at a given GS site. EPA also believes that requiring separate permit applicati ons for each GS well will ensure sufficient review and that the public has an opportunity to provide input on each well in the field as it is constructed or brought online. Comments related to the economics of Class II EOR projects transitioning to Class VI projects is outside the scope of this rulemaki ng. The purpose of this rule is to ensure that GS is conducted in a manner that is protective of USDWs from endangerment.

EPA is developing guidance on transitioning permits from Class II to Class VI. Th e guidance will assist Directors in determining whether an injection project should be transitioned from Class II, where the
p rimary purpose is oil and gas production, to Class VI , where the primary purpose is long-term storage of large volumes of CO2. The guidance describes the methods available for the Director to determine changes in risk to USDWs from projects, and how the Director may determine whether a project should be regulated within the Class II or Class VI UI C program. This guidance wi ll be available on EPA’s website at http://water.epa.gov/t ype/groundwater/uic/wells_sequestra tion.cfm. For more information,
p lease see the discussion on transiti on of Class II wells in the prea mble to the final GS rule.

Comment: TxCCSA Perspectives on the EPA's Propos ed Rule for Geologic Sequestration

While the EPA's Proposed Rule represents a significant step in the development of Carbon Capture and Storage (CCS) as an emissions reduction strategy, the Proposed Rule assumes that sequestration or geologic stor age [FN1] is defined as injection without simultaneous extraction of hydrocarbons, as in the case of enhanced oil recovery (EOR) or enha nced gas recovery (EGR) (e.g., enhanced coal bed methane or ECBM). The Proposed Rule focuses on sequestration outside the context of commercial product extraction and effectively separates CO2 injection into two classe s: sequestration in saline or other non· hydrocarbon related target formations and hydrocarbon related seque stration. In general, this focus reveals several concerns refl ected in the Proposed Rule that the TxCCSA hopes to address, including: 1) the lack of clarificati on of the injectate stream which could lead to the stream be ing considered a waste; 2) the absence of a system for qualifying storage site s; 3) a lack of understanding or the number of wellbores required for scaled ope rations; 4) the attribution of harmful characteristics to the concept of buoyanc y; 5) the lack of consideration for simultaneous storage and hydrocarbon producti on; 6) the post-injection site care timeframe; and 7) multi·st ate jurisdictional issues.

1 While the term sequestration and storage may be used interchangeably, we
p refer the term "storage," as it contem plates recovery of injected CO2 for beneficial use. 2 See Regulatory Determination for Oil and Gas and Geothermal Exploration, Development, and Production Wastes; Regulatory Determination, 53 Fed. Reg. 25445 (July 6, 1988) 3 See the work of Dr. Steven Bryant, dir ector of the Geologic CO2 Storage Joint Industry Project in the Cent er of Petroleum and Geosystems Engineering at the University of Texas. 4 See 73 Fed. Reg. at 43503. 5 ~ Id at 43524. Commenter Name: Darrick Eu g ene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture and Stora g e Association Comment ID: 239556 See Intergovernmental Panel on Clim ate Change, Special Report on Carbon Dioxide Capture und Storage, 208 (Bert, Metz, et al. eds., 2005); see also Sally M. Benson, Carbon Dioxide Capture and Stor age: Research Pathways, Progress and Potential, Global Climate & Energy Pr oject Annual Symposium, October 2007, available at http://pangea.stanford.edulresearctv'bensonlab/present ations/Carbon%20Dioxide%20CaptureYa20and%20Storage%2OY020ResearchO/020Palhways%20Progr ess'Y020and%20Potential.pdf. 7 Chiara Trabucchi and Lindene Patton, Storing Carbon: Opti onsfor Liability Risk. Management, Financia l Responsibility, Daily Environment Report, Bureau of National Affairs, pg. 8 (Sept. 3, 2008). 8 See IPCC 2005 Repon, supra, at 208; see also Benson 9 See Task Force on Carbon Capture and Geologic Storage, The Interstate Oil and Gas Compact Commission, Storage of Carbon Di oxide in Geologic Structures: A Legal and Regulatory Guide for States and Pr ovinces (Sept. 25,2007) available at http://iogcc.mysbopify.comlcollectionslfrontpagelp roductslco2-storage-a ·Legal·andregulatory- guide-for-states-2008. 10 See 73 Fed. Reg. at 43510.

Response: The Agency acknowledges the comment and agrees that GS is a key climate change mitigation technology that is part of a portfolio of options th at could be deployed to reduce CO2 emissions. EPA clarifies that the pur pose of the GS regulation is to ensure that GS is conducted in a manner that protects USDWs from endangerment and only applies to owners or operators of wells injecting CO2 for the purpose of long-term storage.

Please see the remainder of EPA's responses to this comment and the final rule and preamble for further details.

Other EPA Comment Codes and Descriptions: 1630 1.3.3 RCRA/hazardous waste issues (seeking comment) Comment: 25. Perverse incentives: The stringency of the Class VI rules (relative to the other UIC well classe s) may create perverse incentives. For example, an operator could add hydrogen sulfide to the carbon dioxi de stream and then seek a Class I
p ermit with less stringent area of re view, monitoring, post-injection and closure requirements than a Class VI permit. Thus, EPA should review the requirements and applicability of Class I wells in conjunction with the proposed rulemaking for Class VI wells.

Response: EPA disagrees with this comment and does not anticipate this type of scenario will take place because under the final GS rule, owners or operato rs must determine whether the CO2 stream is hazardous under EPA’s RCRA regulat ions; If so, any inj ection of the hazardous CO2 stream may only occur in a Class I hazardous waste injection we ll under 40 CFR Part 146 Subpart G. For Class I hazardous wells, owners or opera tors are required under 40 CFR 286.6 to demonstrate, to a reasonable degree of certainty, that there will be no migration of hazardous constituents from the disposal unit or injection zone for as long as the wastes rema in hazardous or for 10,000 ye ars via a fluid flow no migration petition. EPA anticipates th at this may be very difficult to demonstrate for long-term storage of CO2 at anticipated volumes. Conversel y , Class VI wells cannot be used for the co-in j ection of RCRA Commenter Name: M. Granger Morgan Letter ID: 0233 Commenter Or g anization: Carnegie Mellon University on behalf of the CCS Reg Project Comment ID: 21917hazardous wastes (i.e., hazard ous wastes that ar e injected along with the CO2 stream). EPA received many comments related to RCRA applicab ility to GS sites and ha s decided to initiate a separate proposed rulemaking specifically to examin e the issue of RCRA applicability to CO2 streams being geologically sequest ered, including the possible option of a conditional exemption from the RCRA requirements for CO2 GS in Class VI wells. EPA will consider these comments as part of its development of that proposal. The Agen cy will consider issues particular to RCRA in the context of that separate rulemaking, and recommends that the commen ter read that proposed rule when it is published. The Agency notes that commenters who wish to submit comments on the RCRA proposal will need to do so during the comment period for that rule.

EPA adds that revising the requirements for other cl asses of wells is outside the scope of the GS rulemaking.

Comment: The proposal sets forth a complex regulator y requirement that appears to start under the framework of a Class 1 UIC well, rather than the more appropriate Class 2 UIC well framework, and adds layers of additional regulatory requirements. While we understand that protection of human health and the environment is the mission of EPA, EPA should strive to avoid overly stringent regulatory requirements that could have th e impact of preventing the development of carbon capture technology due to regulat ory burdens associated with dealing with the carbon once it is captured.

Response: EPA disagrees that any of the requirements in the GS rule are unnecessary. Rather, the GS regulation tailors the UIC requirements to address the unique issues associated with large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurit ies in captured CO2, and its mobili ty within subsurface geologic formations.

Please see the remainder of EPA's responses to this comment and the final rule and preamble for further details.

Comment: While Peabody Energy is gene rally supportive of the pr oposed rule, we believe the final rule should be modified to pr ovide greater certainty for CCS projects that would like to proceed in the inte rim prior to promulgation of the final rule. The rule should also provide more certainty and flexibility to convert

Response: EPA recognizes the importance of providing clear, flexible, scalable, and appropriate regulations. EPA believes that th e GS regulation will provide certa inty to industry and the public by
p roviding consistency in requirements across the U.S. and transparency about what requirements apply to owners or operators.

Please see the remainder of EPA's responses to this comment and the final rule and preamble for further details. Commenter Name: Mike Nasi Letter ID: 0254 Commenter Or g anization: Clean Coal Technolo gy Foundation of Texas Comment ID: 22359

Commenter Name: Dianna Tickne r Letter ID: 0262 Commenter Or g anization: Peabod y Ener gy Comment ID: 22991Other EPA Comment Codes and Descriptions: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 Comment: B. Definition of GS

Geologic sequestration and authority

In the proposed rule, EPA has defined geologic sequestration as follows [FR p. 43535, §146.81(d)]:

"Geologic sequestration m eans the long-term containment of a gaseous, liquid or supercritical carbon dioxide stream in subsurface geologic formations. This term does not appl y to its capture or transport."

The proposed rule has cited authority fo r EPA to regulate GS under the Safe Drinking Water Act. However, we believe that EPA should exercise its authority under the Clean Air Act as well to regulate GS for the added purpose of
p reventing releases to the atmosphere , and not just for the purpose of
p rotecting USDWs. Under such authority, the Agency shoul d ensure that any wells
p ermitted for the purposes of GS meet an adequate permanence standard, such as that already promulgated in the UIC rules by the state of Washington, which was based on the IPCC’s findings in its Special Report on Car bon Capture and Storage [FN1]:

"Permanent sequestration means the re tention of greenhouse gases in a containment system using a method that is in accordance with standards approved by the department and that creates a high degree of confidence that substantially ninety nine percent of the greenhouse gases will remain contained for at least one thousand years." [FN2]

Under this added authority, EPA should ensure that Class VI is adequate for the
p urposes of protecting USDWs and for pr eventing releases of CO2 to the atmosphere.

Other wells permitted for GS, whether for that sole purpose or for GS and other
p urposes, should also be subject to regulatory requirements sufficient both to
p rotect USDWs and to prevent releases of CO2 to the atmosphere. Such requirements include, but are not limite d to, adequate site characterization, monitoring, modeling, corrective and remedi al action and closure standards, as well as other requirements that EPA has proposed for Class VI. We cannot endorse the classification of either Class II (as was proposed or as modified by some other commenters) wells or Class VI wells as proposed by EPA in the rule, as the definition only covers protection of USDWs.

[FN1] In its technical summary, IPCC’s Special Report on Ca rbon Capture and Storage states that "With regard to global risks, based on observations and analysis of current CO2 stor age sites, natural systems, engineering systems and models, the fraction retained in appropria tely selected and managed reservoirs is very likely to exceed 99% over 100 year s, and is likely to exceed 99% over 1000 years. Similar fractions retained ar e likely for even longer periods of Commenter Name: David Hawkins Letter ID: 0272 Commenter Or g anization: Natural Resources Defense Council Comment ID: 24076time, as the risk of leakage is expected to decrease over time as other mechanisms provide additional trapping."

[FN2] WAC 173-407-110 Definitions to Part II.

Response: EPA clarifies that the scope of the GS regulation is limited to injection of CO2, and that all requirements in the GS rule ar e designed for the purpose of protecting USDWs from endangerment. Consequently, this comment is outside the scope of the rulemaking. The SDWA does not provide the UIC Program with the authority to de velop regulations for all areas relate d to GS, such as releases to the atmosphere.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

Comment: Our most significant concerns from revi ew of the proposed requirements are organized in four broa d programmatic areas:

(1) Appropriate leve l of regulation;

(2) Appropriate financial assurance fo r long post-injection timeframes;

(3) Flexibility and streamlining in Clas s VI program primacy considerations; and,

(4)Resource needs for regulation of the proposed new class of wells.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment Code: 1220 1.1.1.1 Terminology and definitions Commenter Name: Mark Vicker y Letter ID: 0280 Commenter Or g anization: Texas Commission on Environmental Quality Comment ID: 24097

### Individual Comments

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: For the definition of AoR it needs to be realized that the AoR could be quite sizeable potentially covering many square miles. We suggest using the criteria for the AoR as found in existing 146.6 and for the Pressure Front definition. Otherwise, the AoR as defined could make it impractical to accomplish the work required.

For Geologic Sequestration Project defi nition, our comments for the AoR definition apply also.

Response: The Agency has carefully considered all co mments on the AoR definition at 146.84(a) and modified it to read as follow s: The region surrounding the geologic sequestration project where USDWs may be endangered by the injection activity. The ar ea of review is delineat ed using computational modeling that accounts for the physical and chemical properties of all pha ses of the injected CO2 stream and is based on available site characte rization, monitoring, and operational data.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: Geologic sequestration project means an injection well or wells used to emplace a CO2 stream beneath the lowermost formation containing a USDW, OR ANOTHER FORMATION, IF THE DIRECTOR DETERMINES THAT INJECTION INTO THE OTHER FORMATION WILL NOT ENDANGER USDWS. It in cludes the subsurface 3-D extent of the carbon dioxide plume, asso ciated pressure front, a nd displaced brine, as well as the surface area above that delineated region.

{RRC suggests adding to the end of the first sentence of the definition of Geologic sequestration project, "or a nother formation, if the Director determines that injection into the othe r formation will not endanger USDWs." }

Response: EPA disagrees with the suggested edit. Howe ver, the Agency has modified the final definition of geologic sequestration project at §146.81(d) to read as fo llows: “[A]n injection well or wells used to emplace a carbon di oxide stream beneath the lowermost formation containing a USDW; or, wells used for geologic sequestration of carbon dioxide that have been granted a waiver of the injection depth requirements pursuant to requirements at §146.95; or, wells used for geologic sequestration of carbon dioxide that have received an aquifer exem ption expansion. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surfa ce area above that delineated region.”

EPA adds that the final rule contai ns a new provision for owners or operators to seek a waiver from the injection depth requirements, at §146.95. Based on its evaluation of all public comments and input on the proposed rule and the Notice of Data Availabilit y and Request for Comment, EPA has made man y Commenter Name: Michael H. Cochran Letter ID: 0108 Commenter Or g anization: Bureau of Water, Division of Environment, Kansas Department of Health & Environment (KDHE) Comment ID: 21961

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24759revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Comment: Pressure front means the zone of elevated pressure that is created by the injection of carbon dioxide into the s ubsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressure differential suff icient to cause the movement of injected fluids or formation fluids into a USDW.

{Why does this definition need to be different?}

Response: The definition of a pressure front is unique to the Class VI GS requirements and Subpart H to address the unique nature of CO2 injection for GS, including the potential impact a pressure front may have on USDWs. The final definiti on of pressure front at §146.81(d) is unchanged, and reads as follows: “[T]he zone of elevated pressure that is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressure differential suffic ient to cause the movement of inject ed fluids or formation fluids into a USDW.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: Transmissive fault or fracture means a fault or fracture that has sufficient
p ermeability and vertical extent to allo w fluids to move between formations.

{Recommend that the fault or fracture be "known."}

Response: EPA disagrees with the suggested edit. The final definition of tran smissive fault or fracture at §146.81(d) is unchanged and reads as foll ows: “[A] fault or fra cture that has suffic ient permeability and vertical extent to al low fluids to move between formations.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: (e) A tabulation of all wells within the AOR which penetrate the injection or confining zone(s) . Such data must include a desc ription of each well's type, construction, date drilled, lo cation, depth, record of plu gg in g and/or Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24760

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24761

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24763completion, and any additional inform ation the Director may require;

{Definition of confining zone incl udes multiple formations. Do not imply that multiple confining zone s are preferable to one (good) confining zone.}

Response: EPA disagrees with the suggested edit. The final language in §146.82 is unchanged. EPA retains the requirement to identify additional containment/confining zones, if required by the Director, as proposed in §146.83(b). EPA acknowledges that such additional zones may not be needed in all circumstances, and clar ifies that this requirement is at the Director's discretion, based on his or her understanding of a particular site. EP A believes that, in some situat ions, the presence of additional confining and containment zones above the primar y (i.e., lowermost) confining zone can improve USDW protection. These layers coul d further impede vertical fluid movement and allow for pressure dissipation, and also provide additi onal sites for monitoring, mitigati on, and remediation. The Agency's decision is supported by commenters re presenting states, wate r associations, and an electric utility who assert that these requirements promote a flexible, risk -based, site-specific appro ach to characterizing and
p ermitting a site for GS projects, and would im prove understanding of the project as a whole and
p romote better modeling of the site.

Additionally, the Agency has modified the final definition of confining zone to read as follows: “[A] geologic formation, group of formations , or part of a formation strati graphically overlying the injection zone that acts as barrier to fluid movement. Fo r Class VI wells operating under an injection depth waiver, confining zone means a geologic formation, group of format ions, or part of a formation stratigraphically overlying and unde rlying the injection zone.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: Proposed Mechanical Integr ity Testing Requirements

-"Section 146.89 Mechanical integrity. (a) A Class VI well has mechanical integrity if:

(1) There is no significant leak in the casing, tubing or packer; and (2) There is no significant fluid movement into a USDW through channels adjacent to the injection well bore.

(b) To evaluate the absence of signifi cant leaks under paragraph (a)(1) of this section, owners or operators must...."

There is no definition of "s ignificant" in the document. A definition should be included that explains how th e term will be defined, su ch as some measurement around a mean, a variance interval, etc. Too often the term is used without an understanding of its technical meaning. This will also help the permittee to understand what is expectated. Commenter Name: John Han g e r Letter ID: 0130 Commenter Or g anization: Pennsylvania Dept. of Env. Protection Comment ID: 21508-‘De minimus’ CO2 leakage values should be determined and defined, as well as the acceptable measurement methodol ogy and verification practices.

Response: A properly designed and operated well should have no leakage in the casing, tubing, or
p acker and no fluid movement into a USDW through channels adjacent to the wellbore. While the intent of MITs is to detect these types of problems as early as possible, the goal of the well design and construction requirements at §146.86 is the complete absence of such problems. EPA clarifies that the
p urpose of the "significant leakage" language in th is narrow context is simply to avoid triggering corrective actions for essentially de minimis situations. Determining whether a MIT result should trigger follow-up action is necessarily a case and site-specific situation; as a result, EP A does not believe it is appropriate to define the term "significant leakag e" in the context of MITs. In addition, EPA has not defined this term for purposes of other injection we ll classes and this has not been shown to hinder
p ermitting authorities' and owners or operators' abil ity to assess whether inject ion wells have adequate mechanical integrity. EPA believes that this approach allows states flexibility, will not interfere with the implementation of existing UIC programs, and maintains protection of USDWs from endangerment.

In keeping with its adaptive rulemaking approach, the Agency plans to collect and review data every six years on early GS projects, including MIT data, to determine whether the appropriate amount and types of information and appropriate docum entation are being collected, and to determine if modifications to the requirements are appr opriate or necessary.

Other EPA Comment Codes and Descriptions: 3200 2.2 Proposed Area of Review and Corrective Action Requirements (40 CFR 146.84) Comment: I. Technical Definitions

Area of Review and Fluid M ovement: Adopt the specific language used by the adhoc CO2 workgroup in its Recommendation 3.1 for determining the parameters of each Area of Review, i.e. -- "based on generally accepted and site relevant techniques, such as modeling, that defi ne, in three dimensions, the maximum extent of the modeled CO2 plume [inclusi ve of free phase and water- dissolved CO2]and associated pressure front."

Response: Based on review of all public comments on th e AoR definition at 146.84(a), the Agency has modified it to read as follow s: The region surrounding the geologic sequestration project where USDWs may be endangered by the injection activity. The ar ea of review is delineat ed using computational modeling that accounts for the physical and chemical properties of all pha ses of the injected CO2 stream and is based on available site characterization, monitoring, and operational data. The definition in the
p roposed rule accounted for the varying physical a nd chemical properties of the CO2 including freep hase and wate r -dissolved CO2, as the commenter suggests. The definition in the final rule will continue to do so.

The UIC regulations, including the Class VI regulations, are designed to ensure protection of USDWs from endan g erment. The A g enc y believes that the AoR needs to incorporate not onl y the CO2 itself— Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Ener gy and Climate Chan g e Comment ID: 21578regardless of saturation or phase— b ut also the area of increased pressure ahead of the CO2 plume, which can potentially displace sali ne, native fluids (i.e., naturally occurring salty water) into USDWs. This pressure front would typically encompass an area larger than the plume itself, including any areas of small scale fingering or hete rogeneities or where CO2 saturation is less than 100 percent.

Comment: Mechanical Integrity: Include the term Mechanical Integrity under the phrases originally defined at 40 CFR 146.81(d).

Response: EPA clarifies that mechanical integrity is defined at §146.89(a) as the absence (1) of significant leak in the casing, tubing, or packer a nd (2) of significant fluid movement into a USDW through channels adjacent to the injection wellbore.

Other EPA Comment Codes and Descriptions: 2120 1.6.1 Deep saline formations; 4400 2.4.4.3 Allowing injection above or betw een USDWs (seeking comment) Comment: USDWs and Exempted Aquifers: Re-evaluate the UIC program's curr ent definition of Underground Source of Drinking Water (at 40 CFR 146.3), as applied to Criteria for Exempted Aquifers (at 40 CFR 146.4), in regards to the EPA's total dissolved solids (TDS) standard of <10,000 mg/L.

Response: The Agency acknowledges commenter concerns about water resources and future water resource availability. However, modifying the definition of a USDW is outside the scope of the GS rulemaking. USDWs are defined as aqui fers currently being used as s ources of drinking water or those capable of supplying a public water system and they have a total dissolved solids (TDS) content of 10,000 milligrams per liter or less (§144.3).

The primary goal of the UIC Program under the SDWA is to protect USDWs in order to ensure a reliable supply of drinking water for the American public. The GS rule, as part of the UIC program regulations, continues the progra m’s statutory mandate of ensuri ng the protection of USDWs. The
p ermitting, siting, construction, opera tion, monitoring, and post-injection site care requirements in the GS rule built on a long-standing pr otective regulatory framework, tailor ed to the unique characteristics of CO2 GS.

EPA recognizes that ther e is increasing demand for water res ources and that technology improvements may make high TDS aquifers viable drinking water sources. EPA believes these potential resources should be considered when injection depth waivers are sought. Therefore, the final GS rule at §146.95 (b) requires the Director to consider these issues in determining whether an injection depth waiver is appropriate. Specifically, the Direct or must consider whether alternative injection sites are available; community needs, demands, and supply from drinking wa ter resources; planned ne eds, potential and/or future use of USDWs and non-USDWs in the area; and a plan for securin g alternative resources or Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Energy and Climate Change Comment ID: 21579

Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Ener gy and Climate Chan g e Comment ID: 21580treating USDW formation wate rs in the event of contamination relate d to the Class VI injection activity.

Comment: B. Mechanical Integrity

Recommendation B: Include the term M echanical Integrity under the phrases originally defined at 40 CFR 146.81(d).

Although Mechanical Integrity is defined la ter in the Class VI regulations under its own heading [at 146.89(a)], it would be helpful to include it as a term within the Definitions section at th e beginning of the permitting rules.

Response: EPA clarifies that mechanical integrity is defined at §146.89(a) as the absence (1) of significant leak in the casing, tubing, or packer a nd (2) of significant fluid movement into a USDW through channels adjacent to the injection wellbore.

Comment: A. Owner/Operator Liability

The proposed regulations affect owners and operators of injection wells that will be used to inject CO2 into th e subsurface for purposes of geological sequestration. Owners and operators will be responsible for numerous siting, construction, testing, and monitoring requirements enumerated in the regulations, as well as l ong-term maintenance and fina ncial requirements not yet wholly defined by the proposed regulations. The current regulations define "owner or operator" as "the owner or operator of any 'facility or activity' subject to regulation under the UIC program." [FN2 40 C.F.R. §144.3] The current definitions are insufficient to provide certainty on the key question of what activities are subject to regulation, or could impose some future liability. For example, does "activity" include any pipe lines, pumps, or other infrastructure used to deliver CO2 to the injection well?

Response: The final Class VI GS regulations apply to owners or operators of injection wells that will be used to inject CO2 into the subsurface for the purpos es of GS. Generators and transporters of CO2 are not affected by the Class VI GS rule. The UI C program’s authority unde r the SDWA focuses on ensuring that GS projects are permitted, sited, cons tructed, operated, monitored, and closed in a manner that protects USDWs from endangerment.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information. Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Ener gy and Climate Chan g e Comment ID: 21604

Commenter Name: Robert Bessette Letter ID: 0139 Commenter Or g anization: Council of Industrial Boiler Owners (CIBO) Comment ID: 23979

Commenter Name: Christine Reime r Letter ID: 0142Other EPA Comment Codes and Descriptions: 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: Definition of Underground S ources of Drinking Water

N GWA recommends that US. EPA reevaluate the appropriatene ss of the definition of an underground source of dr inking water (USDW) as one containing less than 10,000 ppm total dissolved solids prior to large-scale licensing of carbon capture and storage (CCS) sites to ensure future drinking water supplies are not unintentionally degraded. Fo r example, a recent article reported that deep brackish ground water, approximately 12,000 TDS, is under consideration as a water source for a development in Sandoval County, New Mexico. The article notes that the cost of water treatment is expected to be less than obtaining existing water rights (Senge bush, 2008) In 2003, water managers in 36 states anticipated shortages in localities, regions , or statewide in the next ten years (U.S. General Accounting O ffice, 2003). The potential for the increased use of brackish ground water for water supplies mu st be anticipated and considered.

Sengebush, Robert M., INTERA, Inc. Deep Brackish Water Considered for New Mexico Development. Southwest Hydrology, March/April 2008, p. 8.

U.S. General Accounting Office. Freshwat er Supply: States’ Views of House Federal Agencies Could Help Them Meet the Challenges of Expected Shortages (GAO-03-514). July 2003, p. 1.

Response: EPA is not changing the USDW definition; chan ging the definition of a USDW is outside the scope of the GS rulemaking. The GS rule focuses on ensuring protection of USDWs, as required under the SDWA, by establishing regulations to ensure th e safe injection of CO2 for long-term storage.

EPA recognizes that ther e is increasing demand for water res ources and that technology improvements may make high TDS aquifers viable drinking water sources. EPA believes these potential resources should be considered when injection depth waivers are sought. Therefore, the final GS rule at §146.95 (b) requires the Director to consider these issues in determining whether an injection depth waiver is appropriate. Specifically, the Direct or must consider whether alternative injection sites are available; community needs, demands, and supply from drinking wa ter resources; planned ne eds, potential and/or future use of USDWs and non-USDWs in the area; and a plan for s ecuring alternative resources or treating USDW formation wate rs in the event of contamination relate d to the Class VI injection activity.

Comment: Proposed Rule: 146.81(d) [Defin ition - Area of review]

Proposed Revision: Area of review m eans the region surrounding the geologic sequestration project that may be impact ed by the injection activity. The area of review is based on computational modeling that accounts for the physical and chemical properties of all phases of the injected carbon dioxide stream and the zone of increased pressure created by the injection.

Rationale: The AOR needs to be based on both the CO2 plume and the associated
p ressure front in order to completel y identif y the areas that ma y be affected b y Commenter Or g anization: National Ground Water Association Comment ID: 22549

Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22589the injection

Proposed Rule: 146.81(d) [Definition - Geologic sequestration project]

Proposed Revision: Geologic sequestration pr oject means an injection well or wells used to emplace a carbon dioxide stream. It includes the subsurface threedimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as all USDWs a nd the surface area above that delineated region.

Rationale: See Section 144.6(f). If an ex emption is provided, USDWs below the CO2 plume or pressure front should be included in the AOR specifically.

Response: EPA agrees that the AoR definition should account for the impact of the CO2 plume on USDWs. The Agency has carefully considered all comments on th e AoR definition at §146.84(a) and modified it to read as follow s: “[T]he region surrounding the ge ologic sequestration project where USDWs may be endangered by the injection activit y. The area of review is delineated using computational modeli ng that accounts for the physical and chem ical properties of all phases of the injected CO2 stream and is base d on available site characterizati on, monitoring, and operational data.”

The Agency has also modified the final definition of geologic sequestration project to read as follows: “Geologic sequestration project mean s an injection well or wells used to emplace a carbon dioxide stream beneath the lowermost form ation containing a USDW; or, well s used for geologic sequestration of carbon dioxide that have been granted a waiver of the injection depth requirements pursuant to requirements at §146.95; or, wells used for geologic se questration of carbon dioxide that have received an aquifer exemption expansion. It includes the s ubsurface three-dimensiona l extent of the carbon dioxide plume, associated pressure front, and displa ced brine, as well as the surface area above that delineated region.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: 1. EPA Should Define "Significant Leakage" Within The Context Of Endangerment.

EPA has defined mechanical integrity as "no significant leakage" and "no significant fluid movement into a USDW through cha nnels adjacent to the injection well bore." While Spectra agrees with EPA’s general approach here, we are concerned that the absence of a definition regarding what constitutes "significant" could create ambiguity that could be construed against the owner/operator and beyond authority grante d under SDWA. Therefore, we would strongly recommend that the Agency define what constitutes "significant" or, alternatively, clarify under what conditions significant leakage might be construed. Toward this end, we believe that the term should be defined and construed within the statutorily defined concept of "endangerment" [2] under SDWA, i.e., si g nificant leaka g e would be defined as an y leaka g e that could Commenter Name: Brianne Metz g e r Letter ID: 0151 Commenter Or g anization: Spectra Energy Corp Comment ID: 21834p otentially endanger a USDW . As one court has held, Congress’ established no specific metric for meas uring endangerment and thus the Agency has the discretion to develop UIC requirements based on vari ed geology, Miami-Dade County v. EPA, 529 F.3d 1049 (11th Cir. 2008) (court upheld EPA’s rule eliminating the non-endangerment finding requirement for Class I municipal injection wells). The amount of leakage and what constitutes significant may vary depending upon the geologic format ions and proximity to USDWs.

2 Endangerment is defined as follows: Underground injection endangers drinking water sources if such injection may resu lt in the presence in underground water which supplies or can reasonably be expect ed to supply any public water system of any contaminant, and if the presence of such contaminant may result in such system’s not complying with any nationa l primary drinking water regulation or may otherwise adversely affect the h ealth of persons. 42 U.S.C. § 300h(d).

Response: A properly designed and operated well should have no leakage in the casing, tubing, or
p acker and no fluid movement into a USDW through channels adjacent to the wellbore. While the intent of MITs is to detect these types of problems as early as possible, the goal of the well design and construction requirements at §146.86 is the complete absence of such problems. EPA clarifies that the
p urpose of the "significant leakage" language in th is narrow context is simply to avoid triggering corrective actions for essentially de minimis situations. Determining whether a MIT result should trigger follow-up action is necessarily a case- and site-specifi c situation; as a result, EPA does not believe it is appropriate to define the term "significant leakag e" in the context of MITs. In addition, EPA has not defined this term for purposes of other injection we ll classes and this has not been shown to hinder
p ermitting authorities' and owners' or operators' abil ity to assess whether inject ion wells have adequate mechanical integrity. EPA believes that this approach allows states flexibility, will not interfere with the implementation of existing UIC programs, and maintains protection of USDWs from endangerment.

In keeping with its adaptive rulemaking approach, the Agency plans to collect and review data every six years on early GS projects, including MIT data, to determine whether the appropriate amount and types of information and appropriate docum entation are being collected, and to determine if modifications to the requirements are appr opriate or necessary.

Other EPA Comment Codes and Descriptions: 4540 2.5.2 Proposed external MIT requirements Comment: EPA is also proposing that an owner/opera tor demonstrate "external mechanical integrity pursuant to § 146.89(c) at leas t once per year." 40 C.F.R. 146.90(e). External mechanical integrity is not defined. Therefore, we would ask EPA to clarify what is meant by this term.

Response: EPA clarifies that mechanical integrity refers to the absence (1) of si gnificant leak in the casing, tubing, or packer and (2) of significant fluid movement into a USDW through channels adjacent to the injection wellbore. The sec ond half of this definition refers to external mechanical integrity.

EPA adds that a properly designed and operated well should have no leakage in the casing, tubing, or
p acker and no fluid movement into a USDW through channels adjacent to the wellbore. While the intent of MITs is to detect these types of problems as early as possible, the goal of the well design and construction requirements at §146.86 is the complete absence of such problems. For additional Commenter Name: Brianne Metzge r Letter ID: 0151 Commenter Or g anization: Spectra Ener gy Corp Comment ID: 21842information, please see the discussion of MITs in the final rule preamble.

Comment: 4. EPA's definition of geologic formati on relies on "layers" of rock as distinguished by its propertie s. Because appropriate sites may not, indeed, be layered, the term "body" of rock, as used by geologists, is more appropriate and responsive to findings that differi ng sites may be suitable to geologic sequestration.

Response: EPA disagrees with the suggested edit. The final definitions of confining zone and injection zone at §146.81(d) continue to use the terms “geol ogic formation, group of formations, or part of a formation.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Comment: 5. EPA's definition of"mechanical integrity" including lack of "significant leakage" may leave the environment and, possibly, safety at risk due to differing interpretations of significance. Small amounts of leakage accumulating over time may become significant. "Signi ficant leakage" requires a definition.

Response: A properly designed and operated well should have no leakage in the casing, tubing, or
p acker and no fluid movement into a USDW through channels adjacent to the wellbore. While the intent of MITs is to detect these types of problems as early as possible, the goal of the well design and construction requirements at §146.86 is the complete absence of such problems. EPA clarifies that the
p urpose of the "significant leakage" language in th is narrow context is simply to avoid triggering corrective actions for essentially de minimis situations. Determining whether a MIT result should trigger follow-up action is necessarily a case and site-specific situation; as a result, EP A does not believe it is appropriate to define the term "significant leakag e" in the context of MITs. In addition, EPA has not defined this term for purposes of other injection we ll classes and this has not been shown to hinder
p ermitting authorities' and owners or operators' abil ity to assess whether inject ion wells have adequate mechanical integrity. EPA believes that this approach allows states flexibility, will not interfere with the implementation of existing UIC programs, and maintains protection of USDWs from endangerment.

The final definition of mechanical integrity is unchanged. EPA clarifies that mechanical integrity is defined at §146.89(a) as the absence (1) of significant leak in the casing, tubing, or packer and (2) of significant fluid movement into a USDW through channels adjacent to the injection wellbore.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information. Commenter Name: Bonnie Lovelace Letter ID: 0152 Commenter Or g anization: Montana Department of Environmental Quality (MDEQ) Comment ID: 22104

Commenter Name: Bonnie Lovelace Letter ID: 0152 Commenter Or g anization: Montana Department of Environmental Quality (MDEQ) Comment ID: 22105Comment: (d) - Definitions - Area of review - as de fined, is equivalent of Class II Radii of Influence - since this is calculated in stead of established as a fixed radius as set by a lot of states' regulations, this will relieve a lot of confusion, especially for the use of horizontal wells

- Geologic sequestration - subsurface emplacement of CO2 - good specification in definition as some more local organizati ons refer to "carbon se questration" as also putting CO2 in wetlands and/or planti ng trees in surface. If states have to establish their own regulations, this de finition could help differentiate the surficial aspect from subsurface sequestration

Response: EPA believes that the use of computational modeling required at §146.84(c)(1), rather than relying on a fixed radius or simple computation, is necessary to ac count for the complexity of GS
p rojects. EPA believes that predic ting the complex multiphase, buoyant flow of the CO2, co-injectates, and compounds that may be mobilized due to injection requires the sophistication of computational models. Models can predict CO2 fate and transport, as well as changes in formation pressure, in three dimensions, as a function of time in order to delineate the subsurface storage site and the AoR. Models can account for site-specific and predicted operating conditions as well as ge ologic heterogeneities and
p otential migration through faults, fract ures, and artificial penetrations.

The Agency has carefully considered all comments on the AoR definition at §146.84(a) and modified it to read as follows: “[T]he re gion surrounding the geologic sequestra tion project where USDWs may be endangered by the injection activity. The area of review is delineated using computational modeling that accounts for the physical and chemical properties of all phases of the injected CO2 stream and is based on available site characterization, monitoring, and operational data.”

The Agency has modified the definition of geologi c sequestration project at §146.81(d) to read as follows: “[A]n injection well or wells used to emplace a carbon dioxide stre am beneath the lowermost formation containing a USDW; or, wells used for ge ologic sequestration of carbon dioxide that have b een granted a waiver of the inje ction depth requirements pursuant to requirements at § 146.95; or, wells used for geologic sequestration of carbon dioxide that have received an aquifer exemption expansion. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surf ace area above that delineated region.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Comment: In the actual text of th e proposed rule’s definition of key terms (page 43535), a geologic storage project is specifically defined as one in which wells are used to "emplace a carbon di oxide stream beneath the lowermost USDW." Was this intentional to rule out thes e other practices that are mentioned in the preamble as items that are still under discussion, by defining a GS project in this narrow manner in the draft rule lan g ua g e? Commenter Name: Steven Pirne r Letter ID: 0153 Commenter Or g anization: South Dakota Department of Environment and Natural Resources Comment ID: 22143

Commenter Name: James Doole y Letter ID: 0156 Commenter Or g anization: Joint Global Change Research Institute, Pacific N orthwest National Laborator y Comment ID: 22627Response: EPA disagrees with the suggested edit and retains the language: "emplace a carbon dioxide stream beneath the lowermost US DW." EPA has modified the defi nition of geologic sequestration
p roject to read as follows: “Geo logic sequestration project means an injection well or wells used to emplace a carbon dioxide stream beneath the lowermost formation c ontaining a USDW; or, wells used for geologic sequestration of carbon dioxide that have been granted a waiver of the injection depth requirements pursuant to requirements at §146.95; or, wells used for geologic sequestration of carbon dioxide that have received an aqui fer exemption expansion. It include s the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displ aced brine, as well as the surface area above that delineated region.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Comment: Lack of Clarity throughout Draft Rule with respect to the "CO2 Stream"

Page 43493 and 43535. The draft Class VI rule has not adequately specified the critical concept of the "CO2 Stream." Th ere are many instances in the rule where critical decisions are made with respect to the "CO2 stream," but this term itself is not well defined nor does it seem to be cons istently used.

o Page 43497. Under "Potential USDW Impacts" the text says that the "CO2 stream" may contain other impurities and lists as an example H2S.

o Page 43493. The Definition of "Geologic Sequestration" only speaks to CO2 being injected.

o Page 43496 contains a discussion about whether CO2 is a commodity or a
p ollutant. This issue of whether CO2 is a commodity or a pollutant is a red herring as far as this Class VI GS rule is concerned and EPA should be commended for saying that its ability to regulate CO2 injection under the SDWA is not contingent on determining whether it is a commodity or a pollutant. However, the rule is never very clear about what an acceptable "CO2 stream" is.

o Pages 43503 and 43504. Are a bi t clearer on what is and is not a "CO2 stream" in the context of a Class VI well but it still is not clear what is allowed and what is not.

o Page 43535. Defines the "carbon dioxide st ream" as CO2 from an anthropogenic source "plus incidental associated substa nces derived from the source materials and the capture process" as well as any tracers. This is more precise as it clearly would rule out the intentiona l comingling of other gaseous waste
p roducts that were not derived from the primary anthropogenic CO2 point source. Yet it still hinges on the rather vague concept of "incidental".

Response: The final definition of carbon dioxide stream at §146.81(d) remains unchan g ed from the rule Commenter Name: James Doole y Letter ID: 0156 Commenter Or g anization: Joint Global Change Research Institute, Pacific N orthwest National Laborator y Comment ID: 22631p roposal and reads as follows: “Carbon dioxide that has been captured from an emission source (e.g., a
p ower plant), plus incidental associated substances derived from the source materials and the capture
p rocess, and any substances added to the stream to en able or improve the inject ion process. This subpart does not apply to any carbon dioxi de stream that meets the definition of a hazardous waste under 40 CFR part 261.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1614 1.3.1.2 Impurities in captured CO2; purity standards for CO2 Comment: The issue of how pure the "CO2 stream" needs to be and whether trace or more significant quantities of othe r gases or liquids can be injected into a Class VI well is a critical issue that will in fluence the overall economics of CCS and could impact the safety and efficacy of GS. Greate r clarity on this issue (while still allowing for some site-spe cific flexibility) would help the business community better understand what the cost of using CCS will be. The USEPA is encouraged to continue trying to narrow the definition of the "CO2 stream" in subsequent versions of the draft rule. While this is a difficult issue and there is no obvious "correct answ er", USEPA is encouraged to continue research and dialogue s with various stakeholders to see if a narrower definition of what degree of co-injection is allowa ble for a Class VI well. It is possible that it could take many y ears maybe even decades to finalize this but it is important to begin pursuing it now.

Response: EPA understands that many CO2 streams may be relatively pure, and research indicates that the estimated amounts of impu rities in a CO2 stream are likely to be low. However, these estimates are based on limited information, and uncertainties remain about the expected concentrations of impurities from the various types of CO2 streams. The concentr ations of minor and trace elements in CO2 streams for GS projects are likely to vary by facility, co al composition, plant operat ing conditions, and pollution removal technologies.

The GS rule does not set generi c purity standards for CO2 injectate streams (e.g., a percent CO2). Instead, the GS rule addresses the quality and quantit y of impurities by requiring owners or operators to submit information on the source of the CO2 and its physical and chemical properties. Specifically, the GS rule requires the owner or operator to submit data about the site, including an analysis of the chemical and physical characteristics of the CO2 stream, as required at §146.82(a)(7)(iv), and information on the compatibility of the CO2 stream wi th fluids in the injection zone and minerals in both the injection and the confining zones and the materials used to constr uct the well, per §146.82(c) (3). This information can help the Director determ ine the potential for geoc hemical reactions between the injectate (CO2) and the host geologic formations, which could resu lt in the plugging of pore spaces or the dissolution of formation minerals. Commenter Name: James Doole y Letter ID: 0156 Commenter Or g anization: Joint Global Change Research Institute, Pacific N orthwest National Laborator y Comment ID: 22632

Commenter Name: James Dooley Letter ID: 0156

Commenter Or g anization: Joint Global Chan g e Research Institute, Pacific Comment ID:Comment: - Page 43493, in the "Definitions." Consid eration should be given to breaking the definition of EOR/EGR into two different short paragraphs. The physical
p rocesses as well as economic drivers invol ved in EOR and EGR are not strictly similar and it is not clear that these s hould be lumped together in something like a federal regulation.

Response: EPA disagrees with the suggested edit. The final definition of enhanced oil or gas recovery (EOR/EGR) remains unchanged. The Agency clarifies that the final Class VI GS rule does not require owners or operators to use GS technologies, nor does it impact business as usual for Class II owners or operators that are injecting CO2 to enhance production of oil or gas. Additionall y, EPA clarifies that the intent of the Class VI GS rule is not to address the use of CO2 for EOR or EGR. Rather, the purpose of the Class VI GS regulation is to ensure that, wher e deployed, GS is conducted in a manner that protects USDWs from endangerment.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: §146.93 Post-injection site care and site clos ure (b)(3) "Prior to authorization for site closure, the owner or operato r must submit to the Director a demonstration, based on monitoring and othe r site-specific data, that the carbon dioxide plume and pressure front have stabilized and that no additional monitoring is needed to assure that th e geologic sequestration project does not
p ose an endangerment to USDWs."

Clarification of the term "s tabilized" is needed. We recommend that the term "stabilized" does not necessarily mean the plume and pressure front are no longer moving, but that the rate and direct ion as defined by confinement zones no longer place an USDW at ri sk. Long-term monitoring s hould have an "end point" defined. Often termed an "e xit strategy", this is a key point that is agreed upon by all parties about what is a "stabl e condition". Monitori ng data includes a prescribed amount of error, thus statistics or other analyses may be required to define a "sta ble condition".

Response: EPA acknowledges that many site-s pecific factors will influence the determination of when the CO2 plume and pressure front no longer pose a risk of endangerment to USDWs. It is for this reason that EPA believes that i ndividual UIC Directors, in consultation with operators, will be in the best
p osition to determine whether additional post-injection site care is needed. EPA expects this decision to be made based on relevant site data and in cons ultation with all potentially impacted parties.

EPA agrees that a complete cessa tion of plume movement may not oc cur at some sites for long time
p eriods due to density diff erences, natural formation flow gradients and diffusion. EPA clarifies that a complete cessation of plume movement is not re quired, only a demonstration that the plume and
p ressure front no longer pose a risk of endangerment to USDWs.

EPA is developin g g uidance to assist owners or operators in evaluatin g well plu gg in g , post-in j ection site N orthwest National Laborator y 22671

Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technolo g ies Council (GTC) Comment ID: 23777care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and m onitoring wells; perform post-inj ection monitoring; demonstrate non endangerment; and perform site closure activities. The guida nce will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Definition of Geological Sequestration Proj ect (GSP) and Area of Review (AoR)

EPA's definitions of GSP and AoR require alignment. Currently the GSP and AoR definitions c onfusingly use different wording to describe similar concepts. It is API's view that these definitions should be essentially the same. API offers languages in our detailed edits that achieve this.

Response: Based on review of all public comments on th e AoR definition at 146.84(a), the Agency has modified it to read as follow s: The region surrounding the geologic sequestration project where USDWs may be endangered by the injection activity. The ar ea of review is delineat ed using computational modeling that accounts for the physical and chemical properties of all pha ses of the injected CO2 stream and is based on available site characterization, monitoring, and operational data. The definition in the
p roposed rule accounted for the varying physical a nd chemical properties of the CO2, including freep hase and wate r -dissolved CO2. The definition in the final rule will continue to do so.

EPA is developing guidance on AoR and corrective action at GS Class VI sites to assist owners or operators and Directors in evaluating requirements and proposed AoR and corrective action plans under 146.84. The guidance describes EPA's recommended appro aches for the data to be considered in an initial AoR delineation, how to apply computational modeling to delineate the AoR, performing corrective action at GS sites, and, when appropriate, completing Ao R reevaluations. The guidance will be available on EPA's web site at http://water .epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: [In this document, the text in all CAPS denotes added text. For redline strike out version of this attachment see PDF Docket ID EPA-HQ-OW-2008-0390-0170.]

Rule Provision: 144.3

API Comments: ENHANCED OIL RECOVERY (EOR) OR ENHANCED GAS RECOVERY (EGR) MEANS ANY ACTIVITY THAT USES FLUIDS, GASES OR OTHER MEANS TO IMPROVE OR INCREASE EXTRACTION OF HYDROCARBONS. Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24130

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24133Rationale: The definition of EOR is nece ssary to support further comments and discussion below.

Response: EPA included the following definition for Enhanc ed Oil or Gas Recovery in the preamble to the rule: typically, the process of in jecting a fluid (e.g., water, brine, or CO2) into an oil or gas bearing formation to recover residual oil or natural gas. The injected fluid thin s (decreases the viscosity) and/or displaces small amounts of extractabl e oil and gas, which is then available for recovery. This is also known as secondary or tertiary recovery.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cla ss VI (seeking comment); 4400 2.4.4.3 Allowing injection above or betw een USDWs (seeking comment) Comment: Rule Provision: 144.6

API Comments: Sections 144.6 - Classification of Wells: (b) Class II. Wells which inject fluids:... (4) FOR ENHANCED RECOVERY OF OI L OR NATURAL GAS WHERE GEOLOGIC SEQUESTRATION IS OCCURRING DURING OR IN CONNECTION WITH ENHANCED RECOVERY OF OIL OR N ATURAL GAS PROVIDED (I) THERE IS REASONABLE EXPECT ATION OF MORE THAN INSIGNIFICANT FUTURE PRODUCTION VOLUMES OR RATES AS A RE SULT OF CARBON DIOXIDE INJECTION AND (II) OPERATING PRESSURES ARE NO HIGHER TH AN REASONABLY NECESSARY TO PRODUCE SUCH VOLUMES OR RATES; AND

(5) FOR GEOLOGIC SEQUESTRATION IN OI L AND GAS FORMATIONS AND WHERE THE CRITERIA OF PARAGRAPH (B)(4) ARE NOT MET

(f) Class VI. Wells used EXCLUSIVELY for geologic sequestration of carbon dioxide STREAMS. beneath the lowe rmost formation containing a USDW WELLS WHERE GEOLOGIC SEQUESTRATION OF CO 2 STREAMS OCCURS DURING OR IN CONNECTION WITH EOR OR EGR ARE REGULA TED UNDER CLASS II.

Rationale: Additionally, there should not be a blanket prohibition concerning injection above USDW’s or at specific dept hs. This is especially true given the
p ossibility of changes in th e definition of a USDW to in clude formations greater than 10,000 parts per million Total Dissolve d Solids. This requirement is not necessary for the protection of USDWs and w ould remove a vast nu mber of viable formations from consideration. Industry has shown that it can operate CO2 injection wells in an EOR context wit hout endangering USDWs that are located below the injection zone. An excellent example is the Salt Creek EOR project in W y omin g , which has a USDW below the in j ection zone. Moreover, under the proposed Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24134rule, there are other measur es that would provide real assurance of formation integrity and require operators to demonstrate th at their project will not endanger USDWs, making the lowermos t USDW restriction unnecessary.

Response: EPA did not make the suggested change. EPA cl arifies that the final rule requires that injection for GS be into non-USDWs below the lo wermost USDW; however, owners or operators may apply for a waiver from this requirement, as described in §146.95. For more information, see the discussion of waivers in the preamble to the final rule.

The Agency disagrees that wells injecting CO2 for the primary purpose of long-term storage should be regulated under Class II requirements. The Agency beli eves that the nature and risks of CO2 injection for the primary purpose of long-term storage pose diff erent risks than injecti on for the primary purpose of ER, and therefore has developed new Class VI regul ations to address these unique risks. For example, the volume of CO2 anticipated to be injected for long-term storage is significantly greater than for ER operations. Reservoir pressure conditi ons will also be different, wi th Class VI injection operations involving large volumes of CO2 and li kely having higher pressures within their storage formations than Class II ER projects.

The final Class VI regulations require that any owner or operator injecting CO2 for the primary purpose of long term storage obtain a Class VI permit with some special consideration for the fact that they are transitioning from a well not originally designed to meet Class VI requirements. The Director has the authority to determine at what point a Class VI perm it is required for those pr ojects that are transitioning from the primary purpose of EOR to long term storage of CO2. The fi nal regulation pr ovides a set of technical factors for the Director to evaluate in making this determin ation, at §144.19. EP A believes that this approach provides suff icient protection of USDWs when there is an increased risk to USDWs as compared to traditional Class II operations while allowing for site -specific flexibility. For more information, please see the di scussion on transition of Class II wells in the preamble to the final GS rule.

EPA is developing guidance on transitioning permits from Class II to Class VI. Th e guidance will assist Directors in determining whether an injection project should be transitioned from Class II, where the
p rimary purpose is oil and gas production, to Class VI , where the primary purpose is long-term storage of large volumes of CO2. The guidance describes th e recommended methods the Director may use to determine changes in risk to USDWs from projec ts, and how the Director may determine whether a
p roject should be regulated within th e Class II or Class VI UIC program. This guidance will be available on EPA’s website at http://w ater.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cla ss VI (seeking comment); 4324 2.4.4.1.2 Comments opposed to requiring inject ion below the lowermost USDW Comment: Rule Provision: 144.80

API Comments: b) Class II. Wells which inject fluids:...... (4 ) FOR ENHANCED RECOVERY OF OIL OR NATURAL GAS WHERE GEOLOGIC SEQUESTRATION IS OCCURRING DURING OR IN CONNECTION WITH ENHANCED RECOVERY OF OIL OR NATURAL GAS PROVIDED (I) THERE IS REASONABLE EXPECTATION OF MORE THAN INSIGNIFICANT FUTURE PRODUCTION VOLUMES Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24137OR RATES AS A RESULT OF CARBON DIOXIDE INJECTION AND (II) OPERATING PRESSURES ARE NO HIGHER THAN REASONABLY NECESSARY TO PRODUCE SUCH VOLUMES OR RATES; AND

(5) FOR GEOLOGIC SEQUESTRATION IN OI L AND GAS FORMATIONS AND WHERE THE CRITERIA OF PARAGRAPH (B)(4) ARE NOT MET

(f) Class VI. Wells used EXCLUSIVELY for geologic sequestration of carbon dioxide STREAMS. WELLS WHERE GEOL OGIC SEQUESTRATION OF CO2 STREAMS OCCURS DURING OR IN CONNECTION WITH EOR OR EGR ARE REGULA TED UNDER CLASS II.

Rationale: See 144.6

Response: As described above regarding the suggested edit at 144.6, EPA did not make the suggested change. The Agency disagrees that wells injectin g CO2 for the primary purpose of long-term storage should be regulated under Class II requirements.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tr ansitioning from Class II to Class VI.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cla ss VI (seeking comment); 4324 2.4.4.1.2 Comments opposed to requiring inject ion below the lowermost USDW Comment: Rule Provision: 146.5

API Comments: b) Class II. Wells which inject fluids:...... (4 ) FOR ENHANCED RECOVERY OF OIL OR NATURAL GAS WHERE GEOLOGIC SEQUESTRATION IS OCCURRING DURING OR IN CONNECTION WITH ENHANCED RECOVERY OF OIL OR NATURAL GAS PROVIDED (I) THERE IS REASONABLE EXPECTATION OF MORE THAN INSIGNIFICANT FUTURE PRODUCTION VOLUMES OR RATES AS A RESULT OF CARBON DIOXIDE INJECTION AND (II) OPERATING PRESSURES ARE NO HIGHER THAN REASONABLY NECESSARY TO PRODUCE SUCH VOLUMES OR RATES; AND

(5) FOR GEOLOGIC SEQUESTRATION IN OI L AND GAS FORMATIONS AND WHERE THE CRITERIA OF PARAGRAPH (B)(4) ARE NOT MET

(f) Class VI. Wells used EXCLUSIVELY for geologic sequestration of carbon dioxide STREAMS. Beneath the lowermos t formation containing an underground source of drinkin g water (USDW). WELLS WHERE GEOLOGIC SEQUESTRATION OF CO2 Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24138STREAMS OCCURS DURING OR IN CONNECTION WITH EOR OR EGR ARE REGULATED UNDER CLASS II.

Rationale: See 144.6

Response: As described above regarding the suggested edit at 144.6, EPA did not make the suggested change. The Agency disagrees that wells injectin g CO2 for the primary purpose of long-term storage should be regulated under Class II requirements.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tr ansitioning from Class II to Class VI.

EPA clarifies that the final rule requires that inje ction for GS be into non-USDWs below the lowermost USDW; however, owners or operators may apply for a waiver from this requirement, as described in §146.95. For more information, see the discussion of waivers in the preamble to the final rule.

EPA acknowledges that there are li mited circumstances where inject ion above the lowermost USDW can be performed in a manner that protects USDW s from endangerment, as long as appropriate
p rotections are in place. However, EPA disagrees with the suggested addition to the regulation. The final GS rule at §146.95 establishes a process by which owners or operators can seek a waiver of the Class VI injection depth requirements for in jection into non-USDW formations above and/or between USDWs. It establishes: 1) requirement s specifying information that owners or operators must submit, and Directors must consider, in consultation wi th PWSS Directors; 2) procedures for public notice of a waiver application and for Director-Regi onal Administrator communication; 3) the waiver issuance process; and, 4) additional requirements that apply to owners or operators of Cl ass VI wells granted a waiver of the injection depth requirements to ensure USDW protection above and below the injection zone.

Other EPA Comment Codes and Descriptions: 3200 2.2 Proposed Area of Review and Corrective Action Requirements (40 CFR 146.84) Comment: Rule Provision: 146.81(d) [Defin ition - Area of review]

API Comments: Area of review mean s the region surrounding the geologic Sequestration project that may be impacted by the injection activity. The area of review is based on computational modeling that accounts for the physical and chemical properties of all phases of the injected carbon dioxide stream. SUBSURFACE THREE-DIMENS IONAL EXTENT OF THE CA RBON DIOXIDE PLUME, ASSOCIATED PRESSURE FRONT, AS WELL AS THE OV ERLYING FORMATIONS AND SURFACE AREA ABOVE THAT DELINEATED REGION.

Rationale: Defining the AOR based on the extent of the CO2 plume and its associated pressure front is a more dire ct approach, rather than the approach offered by the EPA. The EPA definition sugge sts that the computational approach defines the AOR rather than the potenti al risks of the injection activity. Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24142Response: EPA disagrees that the AoR definition needs to specifically include th e overlying formations and surface area above the delineated region. The intent of the Ao R, a long-standing concept within the UIC Program, is to delineate the surface area and all subsurface formations below it that may potentially be impacted by injection activity. A cceptable delineation models will provide predictions of CO2 fate and transport, as well as changes in formation pressure in three dimensions as a function of time that can be used to delineate the subsurface storage si te and the AoR. Although EPA disagrees with the commenter's suggested change, the Agency has carefully considered all comments on the AoR definition at 146.84(a) and modified it to read as follow s: The region surrounding th e geologic sequestration
p roject where USDWs may be endangered by the injection activity. The area of review is delineated using computational modeling that accounts for the physical and chemical properties of all phases of the injected CO2 stream and is based on available site characterization, monitoring, and operational data. EPA believes that this definition is sufficiently br oad and describes both the intent of the computational modeling and the relationship of the AoR to areas that are subject to the risks as sociated with injection.

Other EPA Comment Codes and Descriptions: 1630 1.3.3 RCRA/hazardous waste issues (seeking comment) Comment: Rule Provision: 146.81(d) [Definit ion - Carbon dioxide stream]

API Comments: Carbon dioxide stream mean s carbon dioxide, IN ANY PHYSICAL STATE OR FORM, AND ANY ASSOCIATED substances derived from the that has been captured from an emission source (e.g., a power plant), plus incidental associated substances derived from th e source materials and the capture process, and any, ITS PROCESSING, OR substances added to enable or improve the injection process. This subpart does not apply to any ca rbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.

Rationale: Source of CO2 is not an issu e in the context of defining the CO2 stream. The rule applies to the injection of CO2 and should not address the origins of the materials since that is beyond the scope of this regulation. Original text would have precluded inje ction of CO2 from some sources.

Response: The final GS rule retains the definition of a CO2 stream as proposed. The GS regulation applies to injection of CO2 for the purpose of GS, regardless of the source of the CO2. It is beyond the scope of the GS rule and the UIC Program’s authority to require or set standards for upstream generators of CO2 or purification facilities. For purposes of GS, the UIC program’s authority under the SDWA is limited to ensuring that GS projects are sited, constructed, operate d, and closed in a manner that protects USDWs.

Comment: Rule Provision: 146.81(d) [Definit ion - Geologic sequestration]

API Comments: Geologic sequestration mean s the long-term containment of a gaseous, liquid or supercritical carbon dioxide stream in subsurface geologic formations. This term does not apply to its capture or transport.

Rationale: Added to definition of carbon dioxide stream, so not needed here. Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24143

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24144Response: EPA disagrees with the suggested edit; the fi nal definition of geol ogic sequestration at §146.81(d) reads as follows: “[T]he long-term containment of a gaseous, liquid, or supercritical carbon dioxide stream in subsurface geol ogic formations. This term does not apply to carbon di oxide capture or transport.”

The final definition of carbon dioxide stream also remains unchanged. Carbon dioxi de stream is defined at §146.81(d) as: “[C]arbon dioxide that has been ca ptured from an emissi on source (e.g., a power
p lant), plus incidental associated substances derived from the source materials and the capture process, and any substances added to the stream to enable or improve the injection process. This subpart does not apply to any carbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost USDW Comment: Rule Provision: 146.81(d) [Definition - Geologic sequestration project]

API Comments: Geologic sequestration project means an injection well or wells used to emplace a carbon dioxide stre am beneath the lowermost formation containing a USDW INTO AN INJECTION ZONE EXCL USIVELY FOR THE PURPOSE OF GEOLOGIC SEQUESTRATION. It includes the subsurface three-dimensional extent of the carbon dioxide plume, asso ciated pressure front, a nd displaced brine, as well as the surface area above that delineated region.

Rationale: There should not be a blanket prohibition c oncerning injection above USDW’s or at specific depths. This requirement is not necessary for the
p rotection of USDWs and woul d remove a vast number of viable formations from consideration. Industry has s hown that it can operate CO2 injection wells in an EOR context without endangering USDWs that are located below the injection zone. An excellent example is the Salt Creek EOR project in Wyoming, which has a USDW below the injection zone. Moreover, under the proposed rule, there are other measures that would provide real assura nce of formation integrity and require operators to demonstrate that their project will not endanger USDWs, making the lowermost USDW restriction unnecessary.

Response: EPA acknowledges that there are limited circum stances where injectio n above the lowermost USDW can be performed in a manner that protects USDWs from endangerment, as long as appropriate
p rotections are in place. However, EPA disagrees with the suggested change. For additional information,
p lease see the final rule at §146.95 a nd the preamble, as well as EPA' s responses to comments on the N otice of Data Availability and Request for Comment. Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24145

Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24146Comment: Rule Provision: 146.81(d) [Def inition - Injection zone]

API Comments: Injection zone means a geologic formation, group of formations, or
p art of a formation that is of suffic ient areal extent, thickness, porosity, and permeability to receive carbon dioxide RECEIVING FLUIDS through a well or wells associated with a geologic sequestration project

Rationale: Existing definition in the CFR is sufficient and does not need to be changed. Furthermore, adding the sufficiency requirement is not a definitional issue and should be deal t with elsewhere.

Response: EPA disagrees with the suggested edit. The final definition of injection zone at §146.81(d) remains unchanged, and reads as follows: “[A] geologic formation, group of formations, or part of a formation that is of sufficient areal extent, thickness, porosity, a nd permeability to receive carbon dioxide through a well or we lls associated with a geologic sequestration project.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.81(d) [Definiti on - Post-injection site care]

API Comments: Post-injection site care means appropriate monitoring and other actions (including co rrective action) needed following cessation of injection to assure that USDWs are not endangered , AS REQUIRED UNDER §146.93.

Rationale: Deleted "appropriate" because the definition of it is not clear. Deleted USDW phrase because it is incorporated in 146 requirements.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final appro ach. EPA adds that the owner or operator must monitor as specified in the post-injection site care a nd site closure plan for at least 50 years or for the duration of the alternative timeframe approved by the Director pursuant to requirements in §146.93(c), unless the owner or operator can make a demonstrati on earlier that the geologi c sequestration project no longer poses a risk of endangerment to USDWs.

Comment: Rule Provision: 146.81(d) [Definition - Pressure front]

API Comments: Pressure front means the zone of elevated pressure that is created by the injection of the carbon dioxide STREAM into the subsurface, For the
p urposes of this subpart, the pressure fro nt of a carbon dioxide plume refers to Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24147

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24148a zone where there is a pressure differenti al sufficient to cause movement of injected fluids THE CARBON DIOXIDE STREAM or formation fluids FROM THE INJECTION ZONE into a USDW.

Rationale: Clarification.

Response: EPA disagrees with the suggested edit. The final definition of pressure front at §146.81(d) remains unchanged, and reads as foll ows: “[T]he zone of elevated pressure that is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressure differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.81(d) [Definition - Site closure]

API Comments: Site closure MEANS the point/time, as determined by the Director following the requirements under §146.93, at which the owner or operator of a GS site PROJECT is released from post-injection site care responsibilities.

Rationale: "GS project" is consistent with other definitions.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: Rule Provision: 146.81(d) [Definition - Transmissive faul t or fracture]

API Comments: Transmissive fault or fract ure means a fault or fracture that has sufficient permeability a nd vertical extent to allow fluids to move between formations BEYOND THE CONFINING ZONE.

Rationale: The term "between formations " is inaccurate since there can be multiple formations within a injecti on zone. The critical factor for transmissivity is movement of injected or displaced fluids beyond the confining

zone.

Response: EPA acknowledges the comment but is retaining the requirement in the final rule as ori g inall y proposed under §146.81(d). EPA has retained the de finition in the final rule, which is the Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24149

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24150same as the existing definition at §148.2, to address transmissive faults and fractures that extend beyond the confining zone.

Other EPA Comment Codes and Descriptions: 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: Potential USDW Above 10,000 TDS:

Since states and water utilities in ma ny areas of the U.S. are currently addressing drought and water rights and avai lability issues, the proposed rule should provide for states to include protect ions for well sites with potentially viable sources of drinking water, such as saline aquifers a nd aquifers above 10,000 (mg/L) total dissolved solids (TDS) level that might serve as a viable drinking water sour ce. ASDWA recommends that st ates be allowed regulatory flexibility to consider these aquifers as potential drinking water sources. Please note that there is so me variance among states with regard to this issue. While some states would like Congress to consider changing the current Safe Drinking Water Act (SDWA) language to pr eclude these aquifers as potential sequestration sites, other states are actively looking for additional sequestration sites and would prefer th at the proposed regulation and the current Safe Drinking Water Act (SDW A) language keep the current 10,000 TDS (mg/L) definition for a USDW. Thus, we r ecommend state-specifi c flexibility on this matter.

Response: EPA is not changing the USDW definition; chan ging the definition of a USDW is outside the scope of the GS rulemaking. The GS rule focuses on ensuring protection of USDWs, as required under the SDWA, by establishing regulations to ensure the safe injection of CO2 for long-term storage.

EPA recognizes that ther e is increasing demand for water res ources and that technology improvements may make high TDS aquifers viable drinking water sources. EPA believes these potential resources should be considered when injection depth waivers are sought. Therefore, the final GS rule at §146.95 (b) requires the Director to consider these issues in determining whether an injection depth waiver is appropriate. Specifically, the Direct or must consider whether alternative injection sites are available; community needs, demands, and supply from drinking wa ter resources; planned ne eds, potential and/or future use of USDWs and non-USDWs in the area; and a plan for s ecuring alternative resources or treating USDW formation wate rs in the event of contamination relate d to the Class VI injection activity. For additional information on the waiv er approach, please se e the final rule and preamble, as well as EPA's responses to comments on the Notice of Da ta Availability and Request for Comment.

Other EPA Comment Codes and Descriptions: 3200 2.2 Proposed Area of Review and Corrective Action Requirements (40 CFR 146.84) Comment: Corrective action - As a threshold matter , USWAG believes that the terminology used in the Proposal is problematic; use of the phrase "corrective action" to describe well plugging and re pair risks confusion with the concept of corrective action under either RCRA or CERCLA. As the GAO Report cautions, public Commenter Name: James Taft Letter ID: 0172 Commenter Or g anization: Association of State Drinki ng Water Administrators (ASDWA) Comment ID: 23451

Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utilit y Solid Waste Activities Group (USWAG) Comment ID: 23487p erception is critical to the developmen t of a commercially viable CO2 GS
p rogram. GAO Report at 49. To avoid any unintended and unwarranted negative associations with the phrase "corrective action," USWAG suggests the Final Rule abandon this phrase and instead use a phras e such as "well plugging and repair."

Response: EPA notes that the term "corrective action" at 146.84(d) has been used to describe the
p rocess of addressing improperly plugged wells in the AoR of injection wells since the inception of the UIC Program, e.g., at 146.7 and 146.64. While EPA is awar e that the term has a different meaning under RCRA and CERCLA, this has not caused confusion in the past. The alterna tive term, "well plugging," suggested by the commenter is reserved for in jection well plugging (as indicated at 146.92).

Other EPA Comment Codes and Descriptions: 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: A related issue is how USDW are to be defined under the proposed rules. Current UIC regulations, as well as the preamble to the proposed rules, define USDW as:

An aquifer or portion of an aquife r that supplies any public water system or that contains a sufficient quantity of ground water to supply a public water system, and currently supplies drinking water for human consumption, or that contains fewer than 10,000 mg/l total dissolved solids and is not an exempted aquifer.

EEI recommends that the Agency work with in the current definition of USDW, in
p articular its maximum tota l dissolved solids (TDS) provision, for purposes of CO2 injection and storage. Any change in the definition of USDW would likely require a statutory amendment. The legisl ative history of SDWA identifies the 10,000 TDS standard as one sufficient to ensure that potential drinking water sources that may be tapped in the future are protected,[FN6] and EPA has long recognized this standard in its regulati ons without any serious suggestion over the long and successful history of the UIC program that the standard is inadequate. Thus, any potential alteration to that standard (which implicates a range of public policy issues) should be left to Congress. Some have called for
p otential revision to this standard, but EEI is unaware of any analysis supporting the establishment of an altern ative standard. Nor is EEI aware of any evaluation of the implications of ch anging this standard for long-standing UIC activities, much less on the practic ability of CCS as a critical GHG mitigation tool. In short, even if Congress‘s original expr ession of the 10,000 mg/l standard did not constrain EPA‘s ab ility to change this standard by regulation, EEI is unaware of any foundation in the administrative record that would allow EPA to provide reasoned support for such a change.

[FN6] See H.R. Rep. 93-1185 (1974), reprinted in 1974 U.S.C.C.A.N. 6454, 6484.

Response: EPA is not changing the USDW definition; chan ging the definition of a USDW is outside the scope of the GS rulemaking. The GS rule focuses on ensuring protection of USDWs, as required under the SDWA, by establishing regulations to ensure the safe injection of CO2 for long-term storage.

EPA reco g nizes that there is increasin g demand for water resources and that technolo gy improvements Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23582may make high TDS aquifers viable drinking water sources. EPA believes these potential resources should be considered when injection depth waivers are sought. Therefore, the final GS rule at §146.95 (b) requires the Director to consider these issues in determining whether an injection depth waiver is appropriate. Specifically, the Direct or must consider whether alternative injection sites are available; community needs, demands, and supply from drinking wa ter resources; planned ne eds, potential and/or future use of USDWs and non-USDWs in the area; and a plan for s ecuring alternative resources or treating USDW formation wate rs in the event of contamination relate d to the Class VI injection activity. For additional information on the waiv er approach, please se e the final rule and preamble, as well as EPA's responses to comments on the Notice of Da ta Availability and Request for Comment.

Other EPA Comment Codes and Descriptions: 1230 1.1.1.2 General comments on the regulatory text

Comment: G. VAGUE LANGUAGE AND DE FINITIONAL PROBLEMS

There are many words and phrases in the draft regulations that are not well defined, and the meaning of which ought to be expanded upon. For instance, what might constitute "significan t leakage" in the context of mechanical integrity testing should be identified.

Response: A properly designed and operated well should have no leakage in the casing, tubing, or
p acker and no fluid movement into a USDW through channels adjacent to the wellbore. While the intent of MITs is to detect these types of problems as early as possible, the goal of the well design and construction requirements at §146.86 is the complete absence of such problems. EPA clarifies that the
p urpose of the "significant leakage" language in th is narrow context is simply to avoid triggering corrective actions for essentially de minimis situations. Determining whether a MIT result should trigger follow-up action is necessarily a case and site-specific situation; as a result, EP A does not believe it is appropriate to define the term "significant leakag e" in the context of MITs. In addition, EPA has not defined this term for purposes of other injection we ll classes and this has not been shown to hinder
p ermitting authorities' and owners or operators' abil ity to assess whether inject ion wells have adequate mechanical integrity. EPA believes that this approach allows states flexibility, will not interfere with the implementation of existing UIC programs, and maintains protection of USDWs from endangerment.

The final definition of mechanical integrity is unchanged. EPA clarifies that mechanical integrity is defined at §146.89(a) as the absence (1) of significant leak in the casing, tubing, or packer and (2) of significant fluid movement into a USDW through channels adjacent to the injection wellbore.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: EPA defines "area of review" as "the region surrounding the geologic sequestration project that may be impact ed by the injection activity. The area of review is based on computational modelin g that accounts for the ph y sical and Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23820

Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23874chemical properties of all phases of th e injected carbon dioxide stream." The
p hrase "may be impacted" is too vague, The AoR delineation shoul d be based on or limited by certain risk criteria; ot herwise, an AoR could cover an inappropriately large area that could be expensive to review and characterize.

Response: EPA agrees with commenters that further clarit y is needed with regard to the boundaries of the AoR. After considering the public comments on the proposed GS regulation, EPA has augmented the definition of AoR to better enco mpass the area that may be impact ed by the injection activity (i.e., the "surrounding area" to which the commenter refers). The Agency has modified the AoR definition at 146.84(a) to read as follows: The region surrounding the geologic sequestration project where USDWs may be endangered by the injection activity. The ar ea of review is delineat ed using computational modeling that accounts for the physical and chemical properties of all pha ses of the injected CO2 stream and is based on available site characteri zation, monitoring, and operational data.

EPA is developing guidance on AoR and corrective action at GS Class VI sites to assist owners or operators and Directors in evaluating requirements and proposed AoR and corrective action plans under 146.84. The guidance describes EPA's recommended appro aches for the data to be considered in an initial AoR delineation, how to apply computational modeling to delineate the AoR, performing corrective action at GS sites, and, when appropriate, completing Ao R reevaluations. The guidance will be available on EPA's web site, at http://water .epa.gov/type/groundwater/uic/wells_sequestration.cfm.

Comment: The term "geological sequestration project" is defined as an injection well or wells used to emplace a CO2 stream ben eath the lowermost form ation containing a USDW, including the subsurface three-dime nsional extent of the CO2 plume, associated pressure front, and displaced brine, as well as the surface area above that delineated region. We recomm end removing the phrase "beneath the lowermost formation containing a USDW to reflect our comment suggesting that EPA
p ermit CCS projects above USDWs where feasible. The AoR definition includes additional area that might be impacted and is not defined in terms of the extent of this area.

Response: EPA agrees that the geological sequestration pr oject definition should account for the limited circumstances where inject ion above the lowermost USDW can be performed in a manner that protects USDWs. The Agency has modified the final definition of geologic sequestrati on project to read as follows: “Geologic sequestration project means an inject ion well or wells us ed to emplace a carbon dioxide stream beneath the lowe rmost formation containing a USDW ; or, wells used for geologic sequestration of carbon dioxide that have been granted a waiver of the injection depth requirements
p ursuant to requirements at §146.95; or, wells used for geologic sequestration of carbon dioxide that have received an aquifer exemption expansion. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surface area above that delineated region.”

The final Class VI GS rule at §146.95 establishes a process by which ow ners or operators can seek a waiver of the Class VI injection depth requirements. The waiver ap proach requires the submission of extensive, site-specific information (in conjuncti on with the permit application submission) to demonstrate that injection of CO2 into a non-USDW that is above or between USDWs can be done in a manner that is protective of US DWs. The requirements are designed to ensure that the owner or operator, the Director, and the Re g ional Administrator consider, on a site specific basis, the Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23875implications, benefits, and challenges associated with GS and ensuring water availability and USDW
p rotection.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 4500 2.5 Proposed Mechanical Integrity Testing (MIT) Requirements (40 CFR 146.89) Comment: EPA defines "mechanical integrity" as "the absence of significant leakage within the injection tubing, casing, or packer (known as internal mechanical integrity), or outside of th e casing (known as external mechanical integrity)." The term "significant leakage" is not defined. An overly broad interpretation could result in a finding that mechanical integrity is not being maintained, notwithstanding the absence of any leakage that calls into question the safety of the project or threatens USDWs. EP A should characterize what constitutes "significant" or clarify under what conditions significant leakage might be construed. We suggest defining and construi ng the term within the statutorily defined concept of "endangerment"[FN52] under SDWA, i.e., significant leakage would be defined as any leakage that could potentially endanger a USDW. The amount of leakage and what constitute s significant may vary depending upon the geologic formations and proxi mity to USDWs.[FN53]

[FN52] Endangerment is defined as follows:

Underground injection endangers drinking water sources if such injection may result in the presence in underground water which supplies or can reasonably be expected to supply any public water system of any contaminant, and if the presence of su ch contaminant may result in such system's not complying with any national primary drinking water regulation or may otherwise adversely affect the health of persons. 32 U.S.C. $ 300h(d).

[FN53] Miami-Dade County. EPA, 529 F.3d 1049 (11th Cir. 2008) (upholding EPA's rule eliminating the non-endangerment finding requirement for Class I municipal injection wells).

Response: A properly designed and operated well should have no leakage in the casing, tubing, or
p acker and no fluid movement into a USDW through channels adjacent to the wellbore. While the intent of MITs is to detect these types of problems as early as possible, the goal of the well design and construction requirements at §146.86 is the complete absence of such problems. EPA clarifies that the
p urpose of the "significant leakage" language in th is narrow context is simply to avoid triggering corrective actions for essentially de minimis situations. Determining whether a MIT result should trigger follow-up action is necessarily a case and site-specific situation; as a result, EP A does not believe it is appropriate to define the term "significant leakag e" in the context of MITs. In addition, EPA has not defined this term for purposes of other injection we ll classes and this has not been shown to hinder
p ermitting authorities' and owners or operators' abil ity to assess whether inject ion wells have adequate mechanical inte g rit y . EPA believes that this appr oach allows states flexibilit y , will not interfere with the Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23876implementation of existing UIC programs, and maintains protection of USDWs from endangerment.

In keeping with its adaptive rulemaking approach, the Agency plans to collect and review data every six years on early GS projects, including MIT data, to determine whether the appropriate amount and types of information and appropriate docum entation are being collected, and to determine if modifications to the requirements are appropriate or necessary. For additional information, please see the discussion of MITs in the final rule preamble.

Other EPA Comment Codes and Descriptions: 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: - The 10,000 mg/l TDS limit for classifyi ng USDWs for the siting of Class VI wells needs to be revised upward.

Response: EPA is not changing the USDW definition; chan ging the definition of a USDW is outside the scope of the GS rulemaking. The GS rule focuses on ensuring protection of USDWs, as required under the SDWA, by establishing regulations to ensure the safe injection of CO2 for long-term storage.

Comment: In its comments, AWWA makes several reco mmendations for the following specific items to be included in the final regulation:

- Definition of "endangerment" that incl udes water quality impacts beyond those contaminants with MCLs;

Response: EPA disagrees that endangerment should be defined in the cont ext of the Class VI GS rule. Rather, the Agency clarifies that the purpose of th e Class VI GS regulation, promulgated under authority of the SDWA, is to ensure that, where GS is depl oyed, it is conducted in a manner that protects USDWs from endangerment.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: USDW Classification: The be st sources of drinking wate r are already being used by utilities. In many areas, population growth is forcing utilities to look further or to look at more challenging sources. With the potential impacts from climate change, drinking water utilities ar e facing an even more limited supply of fresh drinking water. As a result, many utilities are turning to more challenging groundwater sources such as those that are very deep or have high salinity concentrations. A dditionally, the pumping cost s for these deep wells are no lon g er prohibitive g iven the lack of sufficient water sources. Some of Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23647

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23649

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23661these new sources could fall outside of the current definition of a USDW, in that the aquifer has a TDS concentrati on higher than 10,000 ppm. The proposed rule promises protection of USDWs from endangerment, in that the activity does not cause a primary drinking water Maxi mum Contaminant Level (MCL) to be exceeded in an USDW or affect human health. There are no anti-degradation
p rovisions in the proposed regulation to protect other groundwater supplies, such as those aquifers that are not classi fied as a USDW but have been, or may be, identified as a future drinking water source. The definition of a USDW was written at a time when many advanced wate r treatment technologies were generally cost prohibitive, and the general thinking that the high-salinity aquifers would never be utilized as dr inking water sources.

Technological advances in the area of de salination have reduced many of the treatment costs, making it more and mo re accessible. Many utilities have no other choice for new water sources. Ever increasing population and water demands have utilities usi ng non-traditional and poorer wate r sources (see Table 1-1 for examples; note that this is not meant to be a comprehensive list of all desalination plants in the United States).

Table 1-1: Water Utilities with More Challenging Water Sources

[The information below was originally pres ented as a table. See Docket PDF EPAHQ-OW-2008-0390-0181 to see a copy of the original table.]

Utility Name: El Paso Water Ut ilities and Ft.Bliss, Texas Water Source: Hueco Bolson Basin Usage: 27.5 mgd TDS Concentrations: 600 to 4,900 mg/l

Utility Name: Tampa Bay Water, Florida Water Source: Seawater Usage: 25 mgd TDS Concentrations: 18,000 - 32,000 mg/L

Utility Name: Yuma Desalting Plant, Arizona Water Source: Drainage water Usage: 22 mgd TDS Concentrations: 3,200 mg/L

Utility Name: Miami-Dade County, Florida Water Source: Florida Aquifer Usage: 17.5 mgd (currently under design) TDS Concentrations: 1,000 - 5,000 mg/L

Utility Name: Temescal Desalter Project, California Water Source: Te mescal Basin Usage: 15 mgd TDS Concentrations: 700 mg/L

Utility Name: City of Abilene, TexasWater Source: Surface water Usage: 8.0 mgd TDS Concentrations: 1,200 mg/L

Utility Name: City of Sherman, Texas Water Source: Surface water Usage: 7.5 mgd TDS Concentrations: 900 - 1500 mg/L

Utility Name: Southmost Regional Water Authority, Texas Water Source: Groundwater Usage: 6.75 mgd TDS Concentrations: 3,500 mg/L

Utility Name: Lake Granbury SWATS,Texas Water Source: Surface water Usage: 6.0 mgd TDS Concentrations: 1,800 mg/L

Utility Name: City of Fort Stockton, Texas Water Source: Groundwater Usage: 6.0 mgd TDS Concentrations: 1485 mg/L

Utility Name: Newport News WTP, Virginia Water Source: Lower and Middle Potomac Aquifers Usage: 5.7 mgd TDS Concentrations: 3600 mg/L

Utility Name: Alameda County Wa ter District, California Water Source: Niles C one Groundwater Basin Usage: 5.0 mgd with expansion to 10 mgd TDS Concentrations: 1,100 - 2,400 mg/L

Utility Name: Pasca goula, Mississippi Water Source: Groundwater Usage: 4.5 mgd TDS Concentrations: 1,000 mg/L

Utility Name: Dare County No rth WTP, North Carolina Water Source: Groundwater Usage: 3.0 mgd TDS Concentrations: 4,300 mg/L

Utility Name: Port Hueneme Brackis h Water Facility, California Water Source: Groundwater Usage: 3.0 mgd TDS Concentrations: 1,300 mg/L

Utility Name: James City Service Authority, Virginia Water Source: Middle and Lower Potomac AquifersUsage: 2.5 mgd TDS Concentrations: 1,000 - 2,400 mg/L

Utility Name: Buxton, North Carolina Water Source: Groundwater Usage: 2.0 mgd TDS Concentrations: 13,200 mg/L

Utility Name: Cape May, New Jersey Water Source: Groundwater Usage: 2.0 mgd TDS Concentrations: 2,100 mg/L

Utility Name: Dare County Cape Hatteras WP, North Carolina Water Source: Groundwater Usage: 2.0 mgd TDS Concentrations: 11,200 mg/L

Utility Name: Las Animas, Colorado Water Source: Groundwater Usage: 1.18 mgd TDS Concentrations: 3,500 mg/L

Utility Name: VA Medical Center, Ft. Lyon, Colorado Water Source: Groundwater Usage: 0.24 mgd TDS Concentrations: 800 mg/L

The use of very deep and/or high salini ty groundwater becoming more commonplace is only a matter of time. Therefore, we believe the 10,000 mg/L TDS USDW definition is no longer appropriate. Gi ven that this regulation does not currently extend protection to non-tradit ional and poorer water sources, AWWA believes that these aquifers may be adve rsely impacted by this rulemaking. These aquifers, which have not been previously used as a drinking water source, may be in the future, and it is important to make sure that they are adequately
p rotected. AWWA recommends that EPA cons ider the "green-effect" and that, in many cases, the overall least cost alternative may be to treat brackish groundwater using desalination technology instead of trying to obtain surface water as the drinking water source. While the surface water may be less expensive to treat, if the utility is located in a dry environment, such as Arizona or New Mexico, the pumping costs to transport that water over a large distance may be much larger than the cost to treat a brackish groundwater. EPA should also consider that as technology evolves, utilitie s will be able to treat a much different set of waters than is currently being treated. Several utilities are using sea water or brackish water as drinking water sources, which would not have been even remotely considered as a viable option 20 years ago, when the TDS limit was originally developed.

Recognizing that it is difficult to exte nd protection to these aquifers due to the restrictions of the SDWA, AWWA recomm ends that the regulation be revised tomandate that, during the project planning process, the owner/operators should include state environmental departments as they can pr ovide insight into what aquifers currently (not classified as US DWs) might be consid ered as future drinking water sources. The stakeholder process s hould also involve both regional and local planning boards, as well as the local utilitie s. This process will allow for protection to be extended to the non-trad itional aquifers, which will be necessary given the pressures on water resources that the country will be facing in the upcoming century.

Response: As described above, EPA is not changing the USDW definition; changing the definition of a USDW is outside the scope of the GS rulemaki ng. The GS rule focuses on ensuring protection of USDWs, as required under the SDWA, by establishing re gulations to ensure the safe injection of CO2 for long-term storage.

Other EPA Comment Codes and Descriptions: 1610 1.3.1 Risks to USDWs; 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: USDW Endangerment: AWWA re commends revision to the definition of "endangerment" in the proposed rule. The current definiti on of endangerment is limited to SDWA UIC definition of 10,000 TDS and to primar y MCL contamination. Certain healtheffects can be related to concentrations in water of compounds that do not exceed the primary MCL. However, under the current language, these potential contaminants would not be covered with the protections afforded by the SDWA.

Response: The Agency acknowledges commenter concerns about water resources and future water resource availability. However, modifying the definition of a USDW or “endangerment” is outside the scope of the GS rulemaking. USDWs are defined as aqui fers currently being used as sources of drinking water or those capable of supplying a public water syst em and they have a total dissolved solids (TDS) content of 10,000 milligrams per liter or less as specified in §144.3. EPA adds that concerns about contaminants with health effects even at concen trations below the maximum contaminant level should be addressed as part of the review process for the national primary drinki ng water regulations; such concerns are outside the scope of this rulemaking. Pl ease note that the definition of “endangerment” has been defined by Congress at SDWA §1421(d)(1)(2).

The primary goal of the UIC Program under the SDWA is to protect USDWs from endangerment in order to ensure a reliable supply of drinking water for the American publ ic. The GS rule, as part of the UIC program regulations, c ontinues the program’s mandate of en suring the protection of USDWs. EPA expects the tailored perm itting, siting, construction, operation, moni toring, and post-injection site care requirements in the GS rule to prevent leakage from injection formations and protect USDWs.

Other EPA Comment Codes and Descriptions: 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: Safe Drinking Water Act Authority: In its February 2008 stak eholders meeting, EPA seemed to imply that it was restricted in what it could regulate and/or require under the SDWA for UIC pro j ects to preventin g "endan g erment of USDW." Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23662

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23667AWWA recognizes that EPA’s regulatory authority is limited by the requirements of the SDWA and will be advocating that several portions of the SDWA be amended to better protect the nati on’s groundwater resources. Issu es that we will be addressing include:

1. The definition of a USDW is provided within the SDWA, which may require amendment if the quality and accessibi lity groundwater sources is to be
p rotected. We recognize that the 10,000 mg /L TDS limit is very outdated, and that a new upper limi t should be established and a pplied when siti ng Class VI wells. We hesitate to recommend any specific number at this point in time, given that some drinking water uti lities are so stressed for water resources that they are investigating extremely non-traditiona l water sources with high TDS levels.

2. Endangerment is defined by the SDWA and may need to be redefined to protect beneficial uses. The proposed rule seems to be focuse d on preventing brine from the carbon dioxide storage formations fr om reaching USDWs and/or preventing carbon dioxide from contaminating USDWs and causing exceedences of primary MCLs. The protective measures of the proposed rule may not be adequate from a source water and beneficial use protection standpoi nt as other changes are likely to occur besides exceeding primary MCLs (e.g., increased Fe/Mn, TDS, and lowered pH - all of which have secondary MCLs and possible increase in silica and boron, which do not have MCLs, but have water quality significance). EPA needs to be
p rovided with the regulatory authority to protect against these other types of endangerment, and the SDWA should be m odified to allow for these protective measures to be developed.

Response: As described above, EPA is not changing the USDW definition; changing the definition of a USDW is outside the scope of the GS rulemaki ng. The GS rule focuses on ensuring protection of USDWs, as required under the SDWA, by establishing re gulations to ensure the safe injection of CO2 for long-term storage.

Other EPA Comment Codes and Descriptions: 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: IV. COMMENTS ON RULE TEXT

Part 144.6(f): Would "lowermost USDW" include formations that ar e not USDW’s at the point of injection but become USDW’s within the extent of the expected area of influence of the injection plume? AW WA recommends that these types of formations be included within the defini tion of USDW based on the ability of carbon dioxide to easily migrate within the confines of an aquifer.

Response: EPA clarifies that the GS rule (and all of th e UIC regulations) require s the protection of all USDWs in the AoR of an injection activity. As part of the site characterizat ion process and during AoR delineation, owners or operators must identify all USDWs within the AoR, model the full extent of the CO2 plume, and demonstrate that all USDWs within the AoR are protected from endangerment. This would include USDWs that are laterally connected to non-USDWs, as suggested by the commenter. Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23718Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language; 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: Part 146.5(f): There is the possibility th at some of the geologic sequestration activities will occur in areas where ther e are no USDWs located in the area of review. These wells should st ill be permitted as Clas s VI wells, and AWWA recommends revising the Class VI definition to:

(f) Class VI. Wells used for geologic sequestration of carbon dioxide in the following applications: 1. Where carbon dioxide is injected belo w the lowermost formation containing a USDW; and, 2. Where carbon dioxide is injected in fo rmations where no USDWs exist within the zone of elevated pressure associated with the injection well.

Wells used for the geologic storage of carbon dioxide in formations above the lowermost USDW are prohibited.

This definition would capture all wells associated with geologic carbon sequestration activities whether or not a USDW was present in the projected footprint of the project.

Response: In the final rule EPA will allow injection into non-USDWs above or between the lowermost USDW where owners or operators can demonstrate th at such injection can be performed in a manner that protects USDWs from enda ngerment, as long as appropriate protections are in place.

EPA adds that, in the final rule at §144.6 (f), Cl ass VI wells are defined as wells that are not experimental in nature that are used for geologic sequestration of carbon dioxide beneath the lowermost formation containing a USDW; or, wells used for ge ologic sequestration of carbon dioxide that have been granted a waiver of the in jection depth requirements pursuant to requirements at §146.95 of this chapter; or, wells used for geologi c sequestration of carbon dioxide that have received an expansion to the areal extent of an existing Class II enhanced oil recovery or enhanced gas recovery aquifer exemption pursuant to §§146.4 of this chapter and 144.7(d).

Other EPA Comment Codes and Descriptions: 1614 1.3.1.2 Impurities in captured CO2; purity standards for CO2 Comment: Part 146.81 AWWA recommends defining the quality of the injection stream and establishing a minimum concentration of carbon dioxide. This requirement for the injection stream will ensure that the injection of other harmful or undesirable gases is limited. Our initial thoughts on th is topic would be that 100% of the injectate must come from a carbon dioxide capture proces s and the injectate must be at least 98% carbon dioxide. Owner/operat ors must ensure that the remaining 2% of the injectate is not made up of compounds that would result in the injectate being classified as a hazardous waste. As AWWA is not an expert on this topic, we would suggest that EPA pursu e research in association with DOE to develop a standard for the minimum conc entration of carbon dioxide in the in

j ection stream. Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23720

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23721Response: As described above, the GS rule does not se t generic purity standards for CO2 injectate streams (e.g., a percent CO2). The final GS rule reta ins the definition of a CO2 stream as proposed.

Comment: Part 146.81(d) AWWA recommends revising th e definition of "pressure front" to read:

Pressure front means the zone of elevat ed pressure that is created by the injection of carbon dioxide into the s ubsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressure different ial sufficient to cause the movement of injected fluids or formation fluids through an injection zone, and/or confining zone, and into a USDW.

Part 146.81(d) AWWA reco mmends revising the definition of "transmissible fault or fracture" to read:

transmissible fault or fract ure means a fault, fracture or other discontinuity that has sufficient permeabil ity and vertical extent to allow fluids to move between formations.

Response: EPA disagrees with the suggested edit. The final definition of pressure front at §146.81(d) is unchanged and reads as follows: “[T] he zone of elevated pressure th at is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressu re differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.”

The final definition of transmissive fault or fractu re at §146.81(d) is unchanged and reads as follows: “[A] fault or fracture that has sufficient permeability a nd vertical extent to allo w fluids to move between formations.” EPA adds that it ch anged the text at §146.84(c)(1)(ii) to include “other discontinuity” to address concern regarding the potential for migration of CO2 at GS sites. It reads as follows: "Take into account any geologic heterogeneities, other discontinuities, data quali ty, and their possible impact on model predictions."

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: IV. EPA Should Update the Definition of USDW So that All Current and Viable Future Drinking Water Supplie s are Protected from GS.

EPA’s definition of what constitutes an "under g round source of drinkin g water" Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23723

Commenter Name: Wend y Jacobs Letter ID: 0183 Commenter Or g anization: Harvard Law School Environmental Law and Policy Cente r Comment ID: 25164("USDW") is critical, b ecause non-USDWs are not protected against potential endangerment from GS operations under the proposed regulation.[FN14] EPA’s continued use of a 1980 definition for USDWs, however, means that many nowviable sources of drinking water fall outside the techni cal definition of "USDW," leaving valuable water s upplies unprotected by the proposed UIC regulation. See 73 Fed. Reg. at 43,492, 43,494. EPA should update the definition of USDW to reflect the current state and foreseeable further advancement of desalination technology. The de finition of USDW should meet the statutory goal of ensuring that all aquifers that "can reasonably be expected to supply any
p ublic water system" are protected from potential contamination. See 42 U.S.C. §300h (a)-(b), (d)(2).

[FN14] 40 C.F.R. §144.3 provides: "[U]SDW me ans an aquifer or its portion: (a) (1) Which supplies any public water system; or (2) Which contains a sufficient quant ity of ground water to supply a public water system; and (i) Currently supplies drinking wate r for human consumption; or (ii)Contains fewer th an 10,000 mg/L total di ssolved solids; and (b) Which is not an exempted aquifer." Thus, the definition also excludes from "U SDW" any aquifer that contains fewer than 10,000 mg/L TDS but does not contain "a sufficient quantity of groundwater to supply a public water system."

Since 1980, when EPA first promulgated th e UIC regulations, "USDW" has been defined narrowly to exclude any aquife r with waters containing more than 10,000 mg/L (also known as 10,000 p.p.m.) total dissolved solids (TDS). See Consolidated Permit Regulations and Technical Criteria and Standards; State Underground Injection Programs, 45 Fed. Reg. 42,472, 42,502 (June 24, 1980) (Final Rule for 40 C.F.R. § 146 and Amendments to § 122; 40 C.F.R. §146.03 (1980)). This numerical limit is the creation of regulation, not statute: the SDWA directed EPA to protect USDW s by publishing regulations for underground injection control programs that include "minimum requirements for effective
p rograms to prevent underground inject ion which endangers drinking wate r sources," which the SDWA defined to mean injection which may contaminate any "underground water which supplies or can reasonably be expect ed to supply any
p ublic water system." See 42 U.S.C. §300h (a)-(b), (d)(2) (emphasis added).

The legislative history supports the posit ion that Congress intended these terms to be construed broadly to effectuate C ongress’s "overriding intent to maximize
p rotection of the public health." In a 1974 report accompanying the SDWA, the House Committee on Interstate a nd Foreign Commerce explained:

[Section 1421 of the SDWA] . . . defines "underground injection which endangers drinking water sources." It is the Committee’s intent that the definition be liberally construed so as to effectua te the preventive and public health
p rotective purposes of the bill. The Committee seeks to protect not only currently-used sources of drinking wa ter, but also potential drinking water sources for the future. This may include water sources which presently exceed minimum intake water quality requirements or maximum contaminant levels or which are not presently accessi ble for use as a community drinking water supply

source.Thus, for example, the Committee expect s the [EPA] Administrator’s regulations at least to require States to provide protection for subsurface waters having less than 10,000 p.p.m. dissolved solids, as is currently done in Illinois and Texas, even though water containing as much as 9,000 p.p.m. would probably require treatment prior to human consumption.

Further contamination of such sources s hould not be permitted if there is any easonable likelihood that these sources will be needed in the future to meet the public demand for drinking water and if these sources may be used for such
p urpose in the future. H. R. Rep. No. 93-1185, pt. C, at 32 (1974) (emphasis added).

Thus, the House Committee offered the 10,000 mg/L standard, in 1974, as a reference point. Then in 1980, EPA stated that it considered alternative
p roposed concentrations to determin e whether any offered "any superio r j ustification in terms of current State practice, human heal th, or technological considerations," but f ound that none did. 45 Fed. Reg. at 42,483. Accordingly, "[i]n the absence of any overriding argumen t to the contrary, the Agency will follow the standard in the House Comm ittee Report accompanying the SDWA." Id.

However, improvements in desalination technology since 1974 and 1980 provide "superior justification" for increasi ng the 10,000 mg/L standard. Water with TDS concentrations above 10,000 mg/L is de salinated using Reverse Osmosis (RO) or Distillation processes that include multistage flash evaporation (MSF), multiple effect distillation (MED), and vapor compressi on (VC). See YUAN ZHOU & RICHARD S.J. TOL, EVALUATING THE COSTS OF DESALINATION AND WATER TRANSPORT, WATER RESOURCES RESEARCH, VOL. 41, avai lable at http://www.unihamburg.de/Wiss /FB/15/Sustainability/wrr desalt.pdf (discussing the variety of desalting technologies). The cost-efficiency of thes e technologies vary with specific site characteristics. Accordingly, the cost per unit depends on size and location of the desalination plant and is highly linked to the price of electricity. "Larger plant capacity reduces the unit cost of water due to economies of scale. Lower energy costs and longer plant peri od reduce unit product water cost." Id.

The data on desalination costs indicate that per unit cost has decreased since the EPA first promulgated the UIC pr ogram in 1980. The average cost of desalinating high TDS concentrations thr ough RO has fallen from $3.70 per m3 in 1979 to about $1.33 per m3 in 2001. For the MSF process, the cost has gone down from $3.04 m3 in 1979 to $.66 m3 in 2001. As for the ME process, the cost has also decreased from $3.56 m3 in 1979 to $1.21 m3 in 2001. Lastly, the average unit cost of VC has gone down from $3.72 m3 in 1979 to $1.50 m3 in 2001.[FN15] See RESEARCH UNIT SUSTAINABILITY AND GLOB AL CHANGE, HAMBURG UNIVERSITY AND CENTRE FOR MARINE AND ATMOSPHERIC SCIENCE, available at http://www.unihamburg.de/Wiss/ FB/15/Sustainability/Models .htm cited in YUAN ZHOU & TOL. at 4.

[FN15] Unit costs are given in terms of 1995 US dollars. See YUAN ZHOU & TOL, supra, at 4.For EPA to meet SDWA’s goal of ensuring that not only all current, but also all reasonably expected, sources of drinking water are protected from GS, EPA must update the 10,000 mg/L reference to refl ect the "reasonable expectations" of today based on the current state and foreseeable further advancement of desalination technology.[FN16]

[FN16] Going forward, EPA should consider revising the definition of USDWs on a rolling basis to prevent the TDS sta ndard from becoming outdated and the resulting endangerment of viable source s of drinking water by GS. In this way, EPA will comply with its Congressional mandate to prevent endangerment of USDWs.

In addition, ELPC and ETIP note that th e proposed regulation excludes from
p rotection aquifers and wells that like ly would not be sufficient to supply water to public water systems [FN17] but that are used as a supply of water for smaller, private systems. At a minimum, EPA should require that owners of small wells be consulted and included in the planning and permitting process for GS wells and that provision be made to provide them with an alternative drinking water source if necessary.

[FN17] "The term ‘public water system’ means a system for the provision to the
p ublic of piped water for human consumpti on, if such system has at least fifteen service connections or regularly serves at least twenty-five individuals." 42 U.S.C. § 300F(4).

Response: EPA recognizes that there is increasing de mand for water resources and that technology improvements may make high TDS aqui fers viable drinking water sources. EPA believes these potential resources should be considered when injection depth waivers are sought. Therefore, the final GS rule at §146.95(b) requires the Director to c onsider these issues in determining whether an injection depth waiver is appropriate. Specifically, the Director must consider whether alternative injection sites are available; community needs, demands, and supply from drinking water res ources; planned needs,
p otential and/or future use of USDWs and non-USDWs in the area; and a plan for securing alternative resources or treating USDW formation waters in th e event of contamination related to the Class VI injection activity.

EPA is not changing the USDW definition; changing the definition of a USDW is outside the scope of the GS rulemaking. The GS rule focuses on ensuring protection of USDWs, as required under the SDWA, by establishing regulations to ensure the safe injection of CO2 for long-term storage. For additional information on the waiver approach, please see the final rule and preamble, as well as EPA's responses to comments on the Notice of Data Availability and Request for Comment.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Rule Provision: 144.6(b)

Proposed CCS Group Recommendations: Add new paragraph (b)(4)

(4) FOR ENHANCED RECOVERY OF OI L OR NATURAL GAS WHERE GEOLOGIC Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24361SEQUESTRATION IS OCCURRING DURING OR IN CONNECTION WITH ENHANCED RECOVERY OF OIL OR N ATURAL GAS PROVIDED (I) THERE IS REASONABLE EXPECT ATION OF MORE THAN INSIGNIFICANT FUTURE PRODUCTION VOLUMES OR RATES AS A RE SULT OF CARBON DIOXIDE INJECTION AND (II) OPERATING PRESSURES ARE NO HIGHER TH AN REASONABLY NECESSARY TO PRODUCE SUCH VOLUMES OR RATES;

Basis for CCS Group Comments: EPA’s Propos al would continue to regulate and
p ermit injection of CO2 for EOR/EGR purposes as Class II inject ion "as long as any production is occurring." EPA has aske d for comment on the merits of this approach "since owners or operators of so me Class II EOR/EGR wells may wish to use wells for the purposes of production and GS prior to the field being completely depleted." 73 Fed. Reg. at 43502. We recommend that the rules be clarified to provide more certainty a bout the applicability of Class II requirements where GS of CO2 occurs in connection with EOR/EGR activities. Specifically, the UIC rules should provide a "bright line" definition as to the applicable class of wells where CO2 inj ection for EOR/EGR production and for GS occur in tandem.

The proposed language describing wells in classification (b)(4) establishes a "bright line" definition for wells that inject CO2 for EOR/EGR and GS and, consistent with EPA’s intent, should remain in Class II and be subject to the current requirements of Class II. We have also agreed that the wells used for GS in oil and gas reser voirs that do not meet the cr iteria of (b)(4) should be subject to additional requirements.

This is the same recommendation as pres ented by the multi-stakeholder group, in which the Carbon Sequestration Council participated.

Response: EPA did not make the suggested change. The Agency disagrees that wells injecting CO2 for the primary purpose of long-term st orage should be regulated under Cla ss II requirements. The Agency believes that the nature and risk s of CO2 injection for the primary purpose of long-term storage pose different risks than injection for the primary purpose of EOR, and ther efore has developed new Class VI regulations to address these unique risks. For example, the volume of CO2 anticipated to be injected for long-term storage is significantly greater than for EOR operations. Re servoir pressure conditions will also be different, with Class VI injection operati ons involving large volumes of CO2 and likely having higher pressures within their storage form ations than Class II EOR projects.

The final Class VI regulations require that any owner or operator injecting CO2 for the primary purpose of long term storage obtain a Class VI permit with some special consideration for the fact that they are transitioning from a well not originally designed to meet Class VI requirements. The Director has the authority to determine at what point a Class VI perm it is required for those pr ojects that are transitioning from the primary purpose of EOR to long term storage of CO2. The fi nal regulation pr ovides a set of technical factors for the Director to evaluate in making this determin ation, at §144.19. EP A believes that this approach provides suff icient protection of USDWs when there is an increased risk to USDWs as compared to traditional Class II operations while allowing for site-specific flexibility.EPA is developing guidance on transitioning permits from Class II to Class VI. Th e guidance will assist Directors in determining whether an injection project should be transitioned from Class II, where the
p rimary purpose is oil and gas production, to Class VI , where the primary purpose is long-term storage of large volumes of CO2. The guidance describes th e recommended methods the Director may use to evaluate changes in risk to USDWs from project s, and how the Director may determine whether a
p roject should be regulated within th e Class II or Class VI UIC program. This guidance will be available on EPA’s website at http://wat er.epa.gov/type/groundwater/uic/wel ls_sequestration.cfm. For more information, please see the di scussion on transition of Class II wells in the preamble to the final GS rule.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Rule Provision: 144.6(f)

Proposed CCS Group Recommendations: (f) Class VI. used for geologic sequestration of carbon dioxide beneath the lowermost formation containing a USDW. Wells INJECTING A CARBON DIOXIDE STREAM FOR GEOLOGIC SEQUESTRATION EXCEPT THOSE WELLS DESCRIBED IN SUBS ECTION (B)(4) OF THIS SECTION OR OTHERWISE EXCLUDED FROM THIS CLASS.

Basis for CCS Group Comments: The changes to (b) and (f) are to recognize that EOR can have a storage component, which is consistent with EPA’s intent as expressed in the preamble. It is wide ly recognized that CO2 based EOR can
p rovide a significant early opportunity fo r carbon storage. As EPA correctly recognizes, CO2 EOR operations can have a significant storage component through capillary trapping or other mechanisms . Operators experien ce supports this approach as they have seen that between 1/3 to 1/2 of the injected CO2 in EOR operations is trapped within the receiving formation during CO2 EOR operations. Following abandonment of EOR operations, assuming the CO2 not trapped in the receiving formation, has not been produced for use in another field, essentially all of the CO2 that has been inj ected can be perm anently stored.

We recommend that all GS into basalts, co al seams, and salt domes be conducted under Class V as experimental wells initially and then as commercial scale Class V wells/projects if the expe rimental projects demonstrate that these sites can be suitable for geological sequestration wh ile preventing endangerment of USDWs.

Keeping these wells under Cla ss V would allow EPA and the states to gain enough experience to develop suitable permitti ng requirements for su ch wells and to tailor those requirements at both the pilot and commercial scales until the agencies are ready to adapt the Class VI regulations.

There should not be a blanket prohibition concerning injection above USDW’s or at specific depths. This requirement is not necessary for the protection of USDWs and would remove a vast number of viable formations from consideration. It has been shown that it is possible to operate CO2 injection wells in an EOR context without endangering USDWs that are located below the injection zone. An excellent example is the Salt Creek EOR pro j ect in W y omin g , which has a USDW Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24362b elow the injection zone. Un der the proposed rule, there are other measures that would provide real assurance of formati on integrity and require operators to demonstrate that their project will not endanger USDWs, making the lowermost USDW restriction unnecessary. Instead, operators should be able to show adequate containment to prevent endangerment of US DWs both above and below the injection zone used for geologic sequestration.

Response: As described above regardin g the suggested edit at 144.6( b), EPA did not make the suggested change. The Agency disagrees that wells injecting CO2 for the primary purpose of long-term storage should be regulated under Class II requirements.

Regarding injection into basalts, coal seams, and salt domes, EPA cl arifies that the GS rule does not categorically preclude injection of CO2 into any non-USDW formation types. The purpose of the GS rule is to ensure protection of USDWs from enda ngerment, and the rule re quires that owners or operators demonstrate that wells are sited in suitab le systems with geologic formations to receive and confine injected CO2, as required at §146.83 of the GS rule. The Class VI siting, well construction and operation, monitoring and testing, and post-injection si te care and site closure requirements are designed to ensure that injected CO2 remains within the target formation. If an owner or operator can demonstrate to the Director's sati sfaction that GS in coal seams, basalts, salt domes, or sh ales can be accomplished in a manner that protects USDWs and meets all of the requirements of the GS rule, the project may be
p ermitted as a Class VI well.

EPA acknowledges that there may be unknown risks associ ated with GS, particularly regarding GS into formations such as coal seams, basalts, and salt domes, which have been the subject of limited experimental projects in the past . EPA anticipates that in the shor t-term, GS into these types of formations will continue to be expe rimental (i.e., if they are to test GS technologies and collect data), and will likely be permitted as Class V experimental technology wells and be subject to UIC Program Guidance #83.

EPA is preparing an addendum to UICPG #83 that describes the use of th e Class V experimental technology well classifica tion to clarify permitting for Class V wells. This addendum will address shifting of Class V experimental projects to Clas s VI projects and the fu ture use of the Class V experimental technology well subclass for research and testing of new GS technologies.

EPA acknowledges that there are li mited circumstances where inject ion above the lowermost USDW can be performed in a manner that protects USDWs. The final GS rule at §146.95 establishes a process by which owners or operators can seek a waiver of the Class VI injection depth requirements. The waiver approach requires the submission of extensive, site-specific information (in conjunction with the
p ermit application submittal) to demonstrate that inj ection of CO2 into a formation that is above or between USDWs can be done in a manner that is pr otective of USDWs. The requirements are designed to ensure the owner or operator, the Director, and the Regional Admini strator consider, on a site-specific basis, the implications, be nefits, and challenges associated with GS and ensuring water availability and USDW protection.

Other EPA Comment Codes and Descriptions: 3200 2.2 Proposed Area of Review and Corrective Action Requirements (40 CFR 146.84) Comment: Rule Provision: 146.81(d) [Defin ition - Area of review] Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24400Proposed CCS Group Recommendations: Ar ea of review means the region surrounding the geologic sequestration project that may be impacted by the injection activity. The area of review is based on computational modeling that accounts for the physical and chemical prope rties of all phases of the injected carbon dioxide stream. SUBSURFACE THREE-DIMENSIO NAL EXTENT OF THE CARBON DIOXIDE PLUME, ASSOCIATED PRESSURE FRONT, AS WELL AS THE OVERLYING FORMATIONS AND SURFACE AREA ABOVE THAT DELINEATED REGION.

Basis for CCS Group Comments: Defining the AOR based on the extent of the CO2
p lume and its associated pre ssure front is a more direct approach, rather than the approach offered by the EPA.

Response: EPA disagrees that the AoR definition needs to specifically include th e overlying formations and surface area above the delineated region. The intent of the Ao R, a long-standing concept within the UIC Program, is to delineate the surface area and all subsurface formations below it that may potentially be impacted by injection activity. A cceptable delineation models will provide predictions of CO2 fate and transport, as well as changes in formation pressu re, in three dimensions, as a function of time that can be used to delineate the subsurface storage site and the AoR. Although EPA disagrees with the commenter's suggested change, the Agency has carefully considered all comments on the AoR definition at 146.84(a) and modified it to read as follow s: The region surrounding th e geologic sequestration
p roject where USDWs may be endangered by the injection activity. The area of review is delineated using computational modeling that accounts for the physical and chemical properties of all phases of the injected CO2 stream and is based on available site characterization, monitoring, and operational data. EPA believes that this definition is sufficiently br oad and describes both the intent of the computational modeling and the relationship of the AoR to areas that are subject to the risks as sociated with injection.

Other EPA Comment Codes and Descriptions: 1630 1.3.3 RCRA/hazardous waste issues (seeking comment) Comment: Rule Provision: 146.81(d) [Definit ion - Carbon dioxide stream]

Proposed CCS Group Recommenda tions: Carbon dioxide str eam means carbon dioxide, IN ANY PHYSICAL STATE OR FORM, AND ANY A SSOCIATED substances derived from the that has been captured from an emi ssion source (e.g., a power plant), plus incidental associated substances deri ved from the source materials and the capture process, and any OR ITS PROCESSING, AND substa nces added to enable or improve the injection proce ss. This subpart does not apply to any carbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.

Basis for CCS Group Comments: Source of CO 2 is not an issue in the context of defining the CO2 stream. The rule applies to the injection of CO2 and should not address the origins of the materials si nce that is beyond the scope of this regulation. Original text would have pr ecluded injection of CO2 from some

sources.

Response: The final GS rule retains the definition of a CO2 stream as proposed. The GS regulation applies to injection of CO2 for the purpose of GS, regardless of the source of the CO2. It is beyond the scope of the GS rule and the UIC Pro g ram’s authorit y to require or set standards for upstream g enerators Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24401of CO2 or purification facilities. For purposes of GS, the UIC program’s authority under the SDWA is limited to ensuring that GS projects are sited, constructed, operate d, and closed in a manner that protects USDWs.

Although the GS regulation does not apply to the source of CO2 streams, the GS rule, at §146.82(a)(7) (iv), requires the owner or operator to submit data about the site, incl uding an analysis of the chemical and physical characteristics of the CO2 stream because the concentrations of minor and trace elements in CO2 streams for GS pr ojects are likely to vary by facili ty, coal composition, plant operating conditions, and pollution removal technologies.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: Rule Provision: 146.81(d) [Definition - Confining zone]

Proposed CCS Group Recommendations: Confining zone mean s a geological formation, group of formations, or part of a formation THAT IS CA PABLE OF LIMITING FLUID MOVEMENT FROM AN INJECTION ZONE.

Basis for CCS Group Comments: The current UIC program definitio n of confining zone is preferable to the propos ed definition. There are no special circumstances for CO2 str eams that warrant a change. In addition, the word "above" should be changed to "from" to accommodate situations where USDWs may be beneath as well as above the injection zone.

Response: EPA did not change the requirement that injection occur below the lowermost USDW. However, the final GS rule cont ains a provision (at §146.95) for owne rs or operators to apply for waivers from the requirement that injection be be low the lowermost USDW. EPA believes this waiver
p rovision will reduce potential limita tions on the re-permitting of Class II wells as Class VI wells,
p rovided they meet the requirements at §146.95, whil e still protecting USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: Rule Provision: 146.81(d) [Definit ion - Corrective action]

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the commenter’ s support; the final GS rule retains the definition.

Comment: Rule Provision: 146.81(d) [Definit ion - Geologic sequestration]

Proposed CCS Group Recommendations: Geolo g ic sequestration means the lon g -term Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24402

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24403

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24404containment of a gaseous, liquid or supercritical carbon dioxide stream in subsurface geologic formations . This term does not apply to its capture or transport.

Basis for CCS Group Comments: Added to definition of carbon dioxide stream, so not needed here.

Response: EPA disagrees with the suggested edit. However, the Agency has modified the definition of geologic sequestration at §146.81(d) to read as follows: “[T]he long-term containment of a gaseous, liquid, or supercritical carbon dioxide stream in subsurface geologi c formations. This term does not apply to carbon dioxide capture or transport.”

The final definition of carbon dioxide stream also remains unchanged. Carbon dioxi de stream is defined at §146.81(d) as: “[C]arbon dioxide that has been ca ptured from an emissi on source (e.g., a power
p lant), plus incidental associated substances derived from the source materials and the capture process, and any substances added to the stream to enable or improve the injection process. This subpart does not apply to any carbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost USDW Comment: Rule Provision: 146.81(d) [Definition - Geologic sequestration project]

Proposed CCS Group Recommendations: Geologic sequestration project means an injection well or wells used to em place a carbon dioxide stream beneath the lowermost formation containing a USDW INTO AN INJECTION ZONE EXCLUSIVELY FOR THE PURPOSE OF GEOLOGIC SEQUESTRATION. It includes the subsurface threedimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surfa ce area above that delineated region.

Basis for CCS Group Comments: There s hould not be a blanket prohibition concerning injection above USDW ’s or at specific depths. This requirement is not necessary for the protection of USDWs and w ould remove a vast nu mber of viable formations from consideration. Industry has shown that it can operate CO2 injection wells in an EOR context wit hout endangering USDWs that are located below the injection zone. An excellent example is the Salt Creek EOR project in Wyoming, which has a USDW below the inje ction zone. Moreover, under the proposed rule, there are other measur es that would provide real assurance of formation integrity and require operators to demonstrate th at their project will not endanger USDWs, making the lowermos t USDW restriction unnecessary.

Response: EPA has revised the definition of a geologic sequestration pr oject to account for the new requirements to include “wells used for geologic se questration of carbon dioxide that have been granted a waiver of the in j ection depth requirements pursuan t to requirements at §146.95.” Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24405Comment: Rule Provision: 146.81(d) [Defin ition - Injection zone]

Proposed CCS Group Recommendations: Inject ion zone means a ge ologic formation, group of formations, or pa rt of a formation that is of sufficient areal extent, thickness, porosity, and perm eability to receive carbon dioxide RECEIVING FLUIDS through a well or wells associated with a geologic sequestration project

Basis for CCS Group Comments: Existing defi nition in the CFR is sufficient and does not need to be changed. Furthermore, adding the sufficienc y requirement is not a definitional issue and shoul d be dealt with elsewhere.

Response: EPA disagrees with the suggested edit. The final definition of injection zone at §146.81(d) is unchanged and reads as follows: “[ A] geologic formation, group of form ations, or part of a formation that is of sufficient areal extent, thickness, poros ity, and permeability to receive carbon dioxide through a well or wells associated with a geologic sequestration project.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.81(d) [Definiti on - Post-injection site care]

Proposed CCS Group Recommendations: Post-injection site care means appropriate monitoring and other actions (including corrective action) needed following cessation of injection to assure that USDWs are not endangered , AS REQUIRED UNDER §146.93.

Basis for CCS Group Comments: Deleted "appr opriate" because the definition of it is not clear. Deleted USDW phrase because it is incorporated in 146 requirements.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach. EPA adds that all post-injection site care must be performed pursuant to the post-injection site care and site closure plan, which must be approved by the Director and demonstrated to include monitoring activities that protect USDWs from endangerment.

Comment: Rule Provision: 146.81(d) [Definition - Pressure front] Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24406

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24407

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24408Proposed CCS Group Recommendati ons: Pressure front means the zone of elevated
p ressure that is created by the injecti on of the carbon dioxide STREAM into the subsurface, For the purposes of this s ubpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pr essure differential sufficient to cause move ment of injected fluids THE CARBON DIOXIDE STREAM or formation fluids FROM THE IN JECTION ZONE into a USDW.

Basis for CCS Group Comments: Clarification.

Response: EPA disagrees with the suggested edit. The final definition of pressure front at §146.81(d) remains unchanged, and reads as foll ows: “[T]he zone of elevated pressure that is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressure differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.81(d) [Definition - Site closure]

Proposed CCS Group Recommendations: Site closure MEANS the point/time, as determined by the Director following the requirements under §146.93, at which the owner or operator of a GS site PROJECT is released from post-injection site care responsibilities.

Basis for CCS Group Comments: "GS project" is consistent with other definitions.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: Rule Provision: 146.81(d) [Definition - transmissible faul t or fracture]

Proposed CCS Group Recommendations: transmissible fault or fracture means a fault or fracture that has sufficient permeabilit y and vertical extent to allow fluids to move between formations BEYOND THE CONFINING ZONE.

Basis for CCS Group Comments: The term "bet ween formations" is inaccurate since there can be multiple formations within an in j ection zone. The critical factor Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24409

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24410for transmissivity is movement of in jected or displaced fluids beyond the confining zone.

Response: EPA has retained the proposed definition, which is the same as the existing definition at §148.2, to address transmissive faults and frac tures that extend beyond the confining zone.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language; 1610 1.3.1 Risks to USDWs; 4400 2.4.4.3 Allo wing injection above or between USDWs (seeking comment) Comment: Issue 3. The proposed regulation currently defines USDWs as z ones that contain groundwater with a total dissolved soli ds (TDS) concentration of less than 10,000 mg/L. This limit should be revised to consider geologic strata with water containing higher TDS concentr ations, because these zones may be economic in the future.

The technology for treating high TDS water for use in water supply is improving rapidly, and these high TDS aquifer zones ma y be needed in the future. In areas with limited water resources water pr oviders are beginning to turn to groundwater sources containing in excess of 10,000 mg/L TDS (Sengebush 2008). It is already conceivable that in th e near future sources with up to approximately 20,000 mg/L TDS will be cons idered viable as water treatment technology advances making such wate r sources economical. To protect groundwater resources which may be economical in the foreseeable future the rule should evaluate the potential that curren tly marginal groundwater sources will be usable. The repository zones should be limited to strata containing very high TDS concentrations that siting studies a nd public input indicate are not likely to be useable in the future, as use of a zone for CO2 sequestration will likely
p reclude recovery and use of the gr oundwater resource in the future.

Sengebush, R. M. 2008, INTERA, Inc. Deep Brackish Water Considered for New Mexico Development. Southwest Hydrol ogy, March/April 2008, p. 8. Available from http://www.swhydro.arizona.edu/ar chive/V7_N2/dept-ontheground.pdf.

Response: The Agency acknowledges the commenter’s concer ns about water resources and future water resource availability. However, modifying the definition of a USDW is outside the scope of the GS rulemaking. USDWs are defined as aqui fers currently being used as s ources of drinking water or those capable of supplying a public water system, with a total dissolved solids (TDS) content of 10,000 milligrams per liter or le ss, as specified in §144.3.

The primary goal of the UIC Program under the SDWA is to protect USDWs from endangerment in order to ensure a reliable supply of drinking water for the American publ ic. The GS rule, as part of the UIC program regulations implemen ting the SDWA, continues the progr am’s mandate of ensuring the
p rotection of USDWs. EPA expects that the tailored permitting, siting, construction, operation, monitoring, and post-injecti on site care requirements in the GS rule will prevent leakage from injection formations and protect USDWs.

EPA recognizes that ther e is increasing demand for water res ources and that technology improvements

ma y make hi g h TDS aquifers viable drinkin g water sources. EPA believes these potential resources Commenter Name: And y Horn Letter ID: 0196 Commenter Or g anization: Colorado Ground Water Association (CGWA) Comment ID: 23923should be considered when injection depth waivers are sought. Therefore, the final GS rule at §146.95 (b) requires the Director to consider these issues in determining whether an injection depth waiver is appropriate. Specifically, the Direct or must consider whether alternative injection sites are available; community needs, demands, and supply from drinking wa ter resources; planned ne eds, potential and/or future use of USDWs and non-USDWs in the area; and a plan for s ecuring alternative resources or treating USDW formation wate rs in the event of contamination relate d to the Class VI injection activity. For additional information on the waiv er approach, please se e the final rule and preamble, as well as EPA's responses to comments on the Notice of Da ta Availability and Request for Comment.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Rule Provision: 144.3

Anadarko Petroleum Corporation (APC) Comm ents: ENHANCED OIL RECOVERY (EOR) OR ENHANCED GAS RECOVERY (EGR) MEANS ANY ACTIVITY THAT USES FLUIDS, GASES OR OTHER MEANS TO IMPROVE OR INCREASE EXTRACTION OF HYDROCARBONS.

Rationale: The definition of EOR is nece ssary to support further comments and discussion below.

Response: EPA includes the following definition of Enhan ced Oil or Gas Recovery in the preamble to the rule: typically, the process of in jecting a fluid (e.g., water, brine, or CO2) into an oil or gas bearing formation to recover residual oil or natural gas. The injected fluid thin s (decreases the viscosity) and/or displaces small amounts of extractabl e oil and gas, which is then available for recovery. This is also known as secondary or tertiary recovery.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cla ss VI (seeking comment); 4400 2.4.4.3 Allowing injection above or betw een USDWs (seeking comment) Comment: Rule Provision: 144.6 and 146.5

Anadarko Petroleum Corporation (APC) Comm ents: (b) Class II. Wells which inject fluids:....

(4) FOR ENHANCED RECOVERY OF OI L OR NATURAL GAS WHERE GEOLOGIC SEQUESTRATION IS OCCURRING DURING OR IN CONNECTION WITH ENHANCED RECOVERY OF OIL OR N ATURAL GAS PROVIDED (I) THERE IS REASONABLE EXPECT ATION OF MORE THAN INSIGNIFICANT FUTURE PRODUCTION VOLUMES OR RATES AS A RE SULT OF CARBON DIOXIDE INJECTION AND (II) OPERATING PRESSURES ARE NO HIGHER TH AN REASONABLY NECESSARY TO PRODUCE SUCH Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24624

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24625VOLUMES OR RATES; AND

(5) FOR GEOLOGIC SEQUESTRATION IN SU BSURFACE GEOLOGIC FORMATIONS IN WHICH EXTRACTION OF HYDROCARBONS HAS OCCURRED, IS OCCURRING OR IS REASONABLY EXPECTED TO OCCUR AND WHERE THE CRITERIA OF PARAGRAPH (B)(4) ARE NOT MET.

(f) Class VI. Wells used EXCLUSIVELY for geologic sequestration of carbon dioxide STREAMS. beneath the lowe rmost formation containing a USDW WELLS WHERE GEOLOGIC SEQUESTRATION OF CO 2 STREAMS OCCURS DURING OR IN CONNECTION WITH EOR OR EGR ARE REGULA TED UNDER CLASS II.

Rationale: The changes to (b) and (f) are to recognize that EOR can have storage component, which is consistent with EPA’ s intent as expressed in the preamble and API’s October 27th meeting with EPA. It is widely recognized that CO2 based EOR can provide a significant early opport unity for carbon storage. As EPA correctly recognizes, CO2 EOR operations can have a significant storage component through capillary tra pping or other mechanisms.

Additionally, there should not be a blanket prohibition concerning injection above USDW’s or at specific depths. Th is is especially true given the
p ossibility of changes in th e definition of a USDW to in clude formations greater than 10,000 parts per million Total Dissolve d Solids. This requirement is not necessary for the protection of USDWs and w ould remove a vast nu mber of viable formations from consideration. Industry has shown that it can operate CO2 injection wells in an EOR context wit hout endangering USDWs that are located below the injection zone. An excellent example is the Salt Creek EOR project in Wyoming, which has a USDW below the inje ction zone. Moreover, under the proposed rule, there are other measur es that would provide real assurance of formation integrity and require operators to demonstrate th at their project will not endanger USDWs, making the lowermos t USDW restriction unnecessary.

Response: EPA did not make the suggested edits. EPA be lieves that the nature and risks of CO2 injection for the primary purpose of long-term storage pose different risk s than injection for the primary
p urpose of ER, and has developed ne w Class VI regulations to address these unique risks. For example, the volume of CO2 anticipated to be injected for long-term storage is significantly greater than for ER. Reservoir pressure conditions will also be different, with Class VI injection operations involving large volumes of CO2 and likely having higher pressures within their stor age formations than Class II ER
p rojects. EPA also recognizes that a by-product of ER activities is that a certain percentage of the CO2 is trapped in the receiving formation.

The final Class VI regulations require that any owner or operator injecting CO2 for the primary purpose of long term storage obtain a Class VI permit with some special consideration for the fact that they are transitioning from a well not originally designed to meet Class VI requirements. The Director has the authority to determine at what point a Class VI perm it is required for those pr ojects that are transitioning from the primary purpose of EOR to long term storage of CO2. The fi nal regulation pr ovides a set of technical factors for the Director to evaluate in making this determin ation, at §144.19. EP A believes that this approach provides suff icient protection of USDWs when there is an increased risk to USDWs as compared to traditional Cla ss II operations while allowing for site-specific flexibility.Regarding injection into basalts, coal seams, and salt domes, EPA cl arifies that the GS rule does not
p reclude injection of CO2 into any non-USDW formation types. The purpose of the GS rule is to ensure
p rotection of USDWs from endangerment, and the rule requires that owners or operators demonstrate that wells are sited in suitable sy stems with geologic formations to r eceive and confine injected CO2, as required at §146.83 of the GS rule. The Class VI si ting, well construction and operation, monitoring and testing, and post-injection site care and site closure requi rements are designed to ensure that injected CO2 remains within the target formation. If an ow ner or operator can demonstrate to the Director's satisfaction that GS in coal seams, basalts, salt domes, or shales can be accomplished in a manner that
p rotects USDWs and meets all of th e requirements of the GS rule, the project may be permitted as a Class VI well.

EPA acknowledges that there may be unknown risks associ ated with GS, particularly regarding GS into formations such as coal seams, basalts, and salt domes, which have been the subject of limited experimental projects in the past . EPA anticipates that in the shor t-term, GS into these types of formations will continue to be experimental (i.e., to test GS technol ogies and collect data), and will likely be permitted as Class V experimental technology wells subject to UIC Program Guidance #83.

EPA is preparing an addendum to UICPG #83 that describes the use of th e Class V experimental technology well classifica tion to clarify permitting for Class V wells. This addendum will address shifting of Class V experimental projects to full-scale GS projects and the future use of the Class V experimental technology well subclass for research and testing of new GS technologies.

EPA acknowledges that there are li mited circumstances where inject ion above the lowermost USDW can be performed in a manner that protects USDWs. The final GS rule at §146.95 establishes a process by which owners or operators can seek a waiver of the Class VI injection depth requirements. The waiver approach requires the submission of extensive, site-specific information (in conjunction with the
p ermit application submittal) to demonstrate that inj ection of CO2 into a formation that is above or between USDWs can be done in a manner that is pr otective of USDWs. The requirements are designed to ensure the owner or operator, the Director, and the Regional Admini strator consider, on a site-specific basis, the implications, be nefits, and challenges associated with GS and ensuring water availability and USDW protection.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cla ss VI (seeking comment); 4324 2.4.4.1.2 Comments opposed to requiring inject ion below the lowermost USDW Comment: Rule Provision: 144.80

Anadarko Petroleum Corporation (APC) Comm ents: (b) Class II. Wells which inject fluids:........(2) for enhanced recovery of oil or natural gas; (3) FOR EOR OR EGR, AND WHERE GEOLOGIC SEQUESTRATI ON OF A CARBON DIOXIDE STREAM IS OCCURRING DURING OR IN CONNECTION WITH EOR OR EG R OPERATIONS OR ACTIVITIES; and (4) For storage of hydrocarbons....

(f) Class VI. Wells used EXCLUSIVELY for geologic sequestration of carbon dioxide STREAMS. WELLS WHERE GEOL OGIC SEQUESTRATION OF CO2 STREAMS OCCURS DURING Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24628OR IN CONNECTION WITH EOR OR EGR ARE REGULA TED UNDER CLASS II.

Rationale: See 144.6

Rule Provision: 146.5

Anadarko Petroleum Corporation (APC) Comm ents: b) Class II. Wells which inject fluids:..... (4) FOR ENHANCED RECOVERY OF OIL OR NATURAL GAS WHERE GEOLOGIC SEQUESTRATION IS OCCURRI NG DURING OR IN CONNEC TION WITH ENHANCED RECOVERY OF OIL OR NATURAL GAS PROVIDED (I) THERE IS REASONABLE EXPECTATION OF MORE THAN INSIGNIFICANT FUTURE PRODUCTION VOLUMES OR RATES AS A RESULT OF CARBON DIOXIDE INJECTION AND (II) OPERATING PRESSURES ARE NO HIGHER THAN REASONABLY N ECESSARY TO PRODUCE SUCH VOLUMES OR RATES; AND

(5) FOR GEOLOGIC SEQUESTRATION IN SU BSURFACE GEOLOGIC FORMATIONS IN WHICH EXTRACTION OF HYDROCARBONS HAS OCCURRED, IS OCCURRING OR IS REASONABLY EXPECTED TO OCCUR AND WHERE THE CRITERIA OF PARAGRAPH (B)(4) ARE NOT MET.

(f) Class VI. Wells used EXCLUSIVELY for geologic sequestration of carbon dioxide STREAMS. Beneath the lowermos t formation containing an underground source of drinking water (USDW). WELLS WHERE GEOLOGIC SE QUESTRATION OF CO2 STREAMS OCCURS DURING OR IN CONNECTION WITH EOR OR EGR ARE REGULATED UNDER CLASS II.

Rationale: See 144.6

Response: As described above in the response to comm ent 24625 regarding the suggested edit at 144.6, EPA did not make the suggested change. The Agency disagrees that wells injecting CO2 for the primary
p urpose of long-term storage should be regulated under Class II requirements.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tr ansitioning from Class II to Class VI.

As described above, the final GS rule at §146.95 establ ishes a process by which owners or operators can seek a waiver of the Class VI injection depth requireme nts for injection into non-USDW formations above and/or between USDWs.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Rule Provision: 146.25 GEOLOGIC SEQUESTR ATION IN OIL OR GAS RESERVOIRS WITHOUT Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24630ENHANCED RECOVERY OF OIL OR NATURAL GAS

Anadarko Petroleum Corporation (APC) Comments: WELLS USED FOR GEOLOGIC SEQUESTRATION AND MEETING THE CLASSIFICATION CRITERIA OF SECTION 146.5(B)(5) SHALL BE SUBJECT TO THE FOLLOWING REQUIREMENTS:

(A) EXISTING WELLS THAT M EET OR EXCEED THE CONSTRUCTION REQUIREMENTS OF § 146.22 SHALL BE SUBJECT TO PART 146, SUBPART H EXCEPT SECTIONS 146.86 AND 146.87. (B) NEW WELLS MUST MET THE CONSTRUCTION REQUIREMENTS OF SECTION 146.22 AND ARE SUBJECT TO PART 146, SUBPART H EXCEPT SECTIONS 146.86 AND 146.87

Rationale: Details of what would be required of "Class IIB" wells are to be worked out during future discussions of the Multi-Stakeholder Discussion Group (MSDG). However, APC offers this language which is consistent with changes APC had suggested before discussions with the MSDG began (see Section 146.81(c)).

Response: As described above in the response to comm ent 24625 regarding the suggested edit at 144.6, EPA did not make the suggested change. The Agency disagrees that wells injecting CO2 for the primary
p urpose of long-term storage s hould be regulated under Class II requirements because Class II requirements do not address the uni que risks posed by GS while en suring protection of USDWs from endangerment.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisi ons to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tran sitioning from Class II to Class VI.

Other EPA Comment Codes and Descriptions: 3200 2.2 Proposed Area of Review and Corrective Action Requirements (40 CFR 146.84) Comment: Rule Provision: 146.81(d) [Defin ition - Area of review]

Anadarko Petroleum Corporation (APC) Comm ents: Area of review means the region surrounding the geologic sequestration project that may be impacted by the injection activity. The area of review is based on computational modeling that accounts for the physical and chemical prope rties of all phases of the injected carbon dioxide stream. SUBSURFACE THREE-DIMENSIO NAL EXTENT OF THE CARBON DIOXIDE PLUME, ASSOCIATED PRESSURE FRONT, AS WELL AS THE OVERLYING FORMATIONS AND SURFACE AREA ABOVE THAT DELINEATED REGION.

Rationale: Defining the AOR based on the extent of the CO2 plume and its associated pressure front is a more dire ct approach, rather than the approach offered by the EPA. The EPA definition sugge sts that the computational approach defines the AOR rather than the potenti al risks of the injection activity.

Response: EPA disa g rees that the AoR definition needs to specificall y include the overl y in g formations Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24633and surface area above the delineated region. The intent of the Ao R, a long-standing concept within the UIC Program, is to delineate the surface area and all subsurface formations below it that may potentially be impacted by injection activity. A cceptable delineation models will provide predictions of CO2 fate and transport, as well as changes in formation pressu re, in three dimensions as a function of time that can be used to delineate the subsurface storage site and the AoR. Although EPA disagrees with the commenter's suggested change, the Agency has carefully considered all comments on the AoR definition at 146.84(a) and modified it to read as follow s: The region surrounding th e geologic sequestration
p roject where USDWs may be endangered by the injection activity. The area of review is delineated using computational modeling that accounts for the physical and chemical properties of all phases of the injected CO2 stream and is based on available site characterization, monitoring, and operational data. EPA believes that this definition is sufficiently br oad and describes both the intent of the computational modeling and the relationship of the AoR to areas that are subject to the risks as sociated with injection.

Other EPA Comment Codes and Descriptions: 1630 1.3.3 RCRA/hazardous waste issues (seeking comment) Comment: Rule Provision: 146.81(d) [Definit ion - Carbon dioxide stream]

Anadarko Petroleum Corporation (APC) Co mments: Carbon dioxide stream means carbon dioxide, WHICH WILL BE IN JECTED IN ANY PHYSICAL STATE OR DISSOLVED, AND ANY ASSOCIATED substances derived from the that has been captured from an emission source (e.g., a power plant), plus in cidental associated substances derived from the source materials and the capture process, and any , ITS PROCESSING, OR substances added to enable or improve the injection process. This subpart does not apply to any carbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.

Rationale: Source of CO2 is not an issu e in the context of defining the CO2 stream. The rule applies to the injection of CO2 and should not address the origins of the materials since that is beyond the scope of this regulation. Original text would have precluded inje ction of CO2 from some sources.

Response: The final GS rule retains the definition of a CO2 stream as proposed. The GS regulation applies to injection of CO2 for the purpose of GS, regardless of the source of the CO2. It is beyond the scope of the GS rule and the UIC Program’s authority to require or set standards for upstream generators of CO2 or purification facilities. For purposes of GS, the UIC program’s authority under the SDWA is limited to ensuring that GS projects are sited, constructed, operate d, and closed in a manner that protects USDWs.

Although the GS regulation does not apply to the source of CO2 streams, the GS rule, at §146.82(a)(7) (iv), requires the owner or operator to submit data about the site, incl uding an analysis of the chemical and physical characteristics of the CO2 stream because the concentrations of minor and trace elements in CO2 streams for GS pr ojects are likely to vary by facili ty, coal composition, plant operating conditions, and pollution removal technologies.

With respect to RCRA, EPA has decided to initia te a separate proposed ru lemaking specifically to examine the issue of RCRA applicability to CO2 streams being geologically sequestered, including the
p ossible option of a conditional exemption from the RC RA requirements for CO2 GS in Class VI wells. EPA will consider these comments as part of its development of that proposal. The A g enc y will consider Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24634issues particular to RCRA in the context of that separate rulemaking, and recommends that the commenter read that proposed rule when it is published. The Agency notes that commenters who wish to submit comments on the RCRA pr oposal will need to do so during the comment period for that rule. Finally, EPA also notes that the fi nal GS rule, which adds new regulat ions for Class VI wells under the Safe Drinking Water Act (SDWA), is not making any changes to the RCRA regulations.

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost USDW; 4400 2.4.4.3 Al lowing injection above or between USDWs (seeking comment) Comment: Rule Provision: 146.81(d) [Definit ion - Geologic sequestration]

Anadarko Petroleum Corporation (APC) Co mments: Geologic sequestration project means an injection well or wells used to emplace a carbon dioxide stream beneath the lowermost formation containing a USDW INTO AN INJECTION ZONE EXCLUSIVELY FOR THE PURPOSE OF GEOLOG IC SEQUESTRATION. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated
p ressure front, and displaced brine, as well as the surface area above that delineated region.

Rationale: There should not be a blanket prohibition c oncerning injection above USDW’s or at specific depths. This requirement is not necessary for the
p rotection of USDWs and woul d remove a vast number of viable formations from consideration. Industry has s hown that it can operate CO2 injection wells in an EOR context without endangering USDWs that are located below the injection zone. An excellent example is the Salt Creek EOR project in Wyoming, which has a USDW below the injection zone. Moreover, under the proposed rule, there are other measures that would provide real assura nce of formation integrity and require operators to demonstrate that their project will not endanger USDWs, making the lowermost USDW restriction unnecessary.

Response: EPA has revised the definition of a geologic sequestration pr oject to account for the new requirements to include “wells used for geologic se questration of carbon dioxide that have been granted a waiver of the injection depth require ments pursuant to requirements at §146.95.”

Comment: Rule Provision: 146.81(d) [Defin ition - Injection zone]

Anadarko Petroleum Corporation (APC) Comm ents: Injection zone means a geologic formation, group of formations , or part of a formation that is of sufficient a real extent, thickness, porosity, and permeability to receive carbon dioxide RECEIVING FLUIDS through a well or wells associated with a geologic sequestration project

Rationale: Existing definition in the CFR is sufficient and does not need to be changed. Furthermore, adding the sufficiency requirement is not a definitional issue and should be de alt with elsewhere. Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24635

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24636Response: EPA disagrees with the suggested edit. The final definition of injection zone at §146.81(d) is unchanged and reads as follows: “[ A] geologic formation, group of form ations, or part of a formation that is of sufficient areal extent, thickness, poros ity, and permeability to receive carbon dioxide through a well or wells associated with a geologic sequestration project.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.81(d) [Definiti on - Post-injection site care]

Anadarko Petroleum Corporation (APC) Comm ents: Post-injection site care means appropriate monitoring and other actions (including corrective action) needed following cessation of injection to assure that USDWs are not endangered , as required under §146.93.

Rationale: Deleted "appropriate" because the definition of it is not clear. Deleted USDW phrase because it is incorporated in 146 requirements.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach. EPA adds that all post-injection site care must be performed pursuant to the post-injection site care and site closure plan, which must be approved by the Director and demonstrated to include monitoring activities that protect USDWs from endangerment.

Comment: Rule Provision: 146.81(d) [Definition - Pressure front]

Anadarko Petroleum Corporation (APC) Commen ts: Pressure front means the zone of elevated pressure that is created by the injection of the carbon dioxide STREAM into the subsurface, For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressure differential sufficient to cause move ment of injected fluids THE CARBON DIOXIDE STREAM or formation fluids FROM THE IN JECTION ZONE into a USDW.

Rationale: Clarification.

Response: EPA disagrees with the suggested edit. The final definition of pressure front at §146.81(d) is unchanged and reads as follows: “[T] he zone of elevated pressure th at is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressu re differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.” Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24637

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24638Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.81(d) [Definition - Site closure]

Anadarko Petroleum Corporation (APC) Comments: Site closure MEANS the
p oint/time, as determined by the Director following the requirements under §146.93, at which the owner or operator of a GS site PROJECT is released from post-injection site care responsibilities.

Rationale: "GS project" is consistent with other definitions.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: Rule Provision: 146.81(d) [Definition - Transmissive faul t or fracture]

Anadarko Petroleum Corporation (APC) Comm ents: Transmissive fault or fracture means a fault or fracture that has suffic ient permeability and vertical extent to allow fluids to m ove between formations BEYOND THE CONFINING ZONE.

Rationale: The term "between formations " is inaccurate since there can be multiple formations within a injecti on zone. The critical factor for transmissivity is movement of injected or displaced fluids beyond the confining

zone.

Response: EPA has retained the proposed definition, which is the same as the existing definition at §148.2, to address transmissive faults and frac tures that extend beyond the confining zone.

Comment: Corrective action - As the GAO Report obs erves, public perception of carbon sequestration will likely play a determinative role in th e success of any CO2 GS regulatory scheme. GAO Report at 49. The us e of the phrase "corrective action" to describe plugging and repa ir of Class VI wells risks confusion and possibly negative associations with the concep t of corrective action under RCRA and CERCLA. We encoura g e EPA to replace the phrase "corrective action" with more Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24639

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24640

Commenter Name: Chris M. Hobson Letter ID: 0201 Commenter Or g anization: Southern Compan y Comment ID: 22169appropriate terminology in the Final Rule.

Response: EPA notes that the term "corrective action" at §146.84(d) has been used to describe the
p rocess of addressing improperly plugged wells in the AoR of injection wells since the inception of the UIC program, e.g., at §§146.7 and 146.64. While EPA is aware that the term has a different meaning under the UIC regulations than it does under RCRA and CERCLA, this ha s not caused confusion in the
p ast. An alternative term, "well plugging," suggested by another commen ter is reserved for injection well plugging, as indicated at §146.92.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Comment: §146.81 Applicability. (b) "This subpart applies to we lls used to inject carbon dioxide specifically for the purpose of geologic sequestration, i.e ., the long-term containment of a gaseous, liquid or supercri tical carbon dioxide stream in subsurface geologic formations."

We recommend striking out "gaseous, liquid or supercritical carbon dioxide stream" and replacing with "gaseous, liquid, supercriti cal or co-mixed carbon dioxide stream" This change will allow fo r injection of carbon dioxide that is
p re-dissolved with water to prevent phase separation in the injection zone or with inclusion of flow or pum ping enhancement components.

Response: EPA disagrees with the suggested edit. The Agency has modified §146.81(b) to read as follows: “This subpart applies to any wells used to inject carbon dioxide specifically for the purpose of geologic sequestration, i.e., the l ong-term containment of a gaseous, liquid, or supercritical carbon dioxide stream in subsurface geologic formations.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: 1. AOR Definition

The proposed rule vaguely defines the AO R as "the region surrounding" the GS
p roject that "may be impacted by the injection activity." 72 Fed. Reg. at 43535 (proposed 40 C.F.R. 146.81(d)). The defini tion goes on to suggest that the AOR is to be "based on co mputation modeling that accounts for the physical and chemical properties of all phases of th e injected carbon dioxide stream." Id. There are two issues. Commenter Name: Richard Guinn Letter ID: 0210 Commenter Or g anization: Eastman Chemical Compan y Comment ID: 22719

Commenter Name: John Kin g Letter ID: 0211 Commenter Or g anization: Shell Exploration and Production Company (SEPCo) Comment ID: 22767First, the proposed definition suggests the need for a more complex modeling approach than may typically be necessary or appropriate. As experience with hazardous waste injection shows, it is rarely necessary to attempt to model chemical changes in the injectate plume. Indeed, it is typically far easier to model transport than chemical fate, a nd conservative mode ling of transport should typically be sufficient by itself to show that USDWs will not be endangered. Where this is the case, it is containment of the plume -- rather than the precise composition of the plume -- that matters, and modeling of chemical changes would be unnecessary. Similarly, the pream ble suggests that the "most sophisticated" and most "accurate" mode ling should be preferred or even required. 73 Fed. Reg. at 43507. Again, howev er, the appropriate goal is to ensure protection of USDWs, and simpler, more conservative modeling may often be sufficient (and even preferable) for this purpose.

Second, the functional purpose of the AOR is to define the area within which impacts of the injection activity c ould cause endangerment of a USDW; specifically, the AOR defines the area within which corrective action for abandoned boreholes may be necessary to prevent endangerment of USDWs. The language of the proposed ru le (i.e., "may be imp acted by the injection activity") is not clearly lim ited to impacts of the injection activity that could cause endangerment of USDW’s, and it should be.

Response: EPA believes that predicting the complex multiphase, buoyant flow of the CO2, coinjectates, and compounds that ma y be mobilized due to injection requires the sophistication of computational models, as required at 146.84(c)(1). Models can predict CO2 fate and transport, as well as changes in formation pressure, in three dimensions, as a function of time in order to delineate the subsurface storage site and the AoR. Models ca n account for site-specific and predicted operating conditions as well as geologic heterogeneities a nd potential migration through faults, fractures, and artificial penetrations.

EPA acknowledges that fine precisi on may not always be necessary and that many factors determine ultimate confidence in modeling results. However, EPA does not be lieve that more precision would result in a less protective modeling approach. EPA anticipates that the owner or operator, in consultation with the Director, will choose the mode l that is most appropriate for a particular GS project, and that this dialogue is a key factor in assuring that the GS site is modeled (and eventually operated and tracked) in a manner that protects USDWs from endangerment. EPA encourages and expects ow ners or operators to use the best multiphase, computational models available.

Other EPA Comment Codes and Descriptions: 1616 1.3.1.3 Fluid movement Comment: Point #4: The use of the term "CO2 buoyanc y," enumerated countless times in the draft rules, is misleading. The Preamble to the Proposed Rule makes very clear that changes to the VIC program for CO 2 geologic storage are based among other things on the assertion that CO2 is "buoyant ". This is simply incorrect. CO2 is a non-explosive, non-flammable, non-toxic gas that possesses different physical
p roperties than some other injectates or existing formation fluids. These
p hysical properties do not include any special buoyancy characteristics or
p roperties. Rather, CO2 is simply more dense than some unde rground fluids or
g ases and less dense than others. Hence the movement of in j ected CO2 in a Commenter Name: Darrick Eugene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture and Stora g e Association Comment ID: 23961reservoir, or any type of system containing different fl uids or gases, will vary based on the relative densities of the va rious formation fluids or gases that are in the reservoir. The various formati on fluids will simply segregate based on the relative densities of the fluids or gases, including CO2. As a result, CO2 may be the fluid that sinks to the bottom, rises to the top, or resides somewhere in between the top and the bottom within the reservoir system.

Response: EPA disagrees with the commenter. Field and laboratory studies that evaluated two deep wells exposed to CO2 for nearly three decades have provided evidence of upward vertical flow of CO2. In Carey et al (2007), a sample of we ll cement collected from a section of well in the confining zone at SACROC showed evidence of cement alteration (car bonation) due to exposure from CO2. (The study was not able to determine whether the alteration was due to exposure to CO2 in the presence of water, dry CO2, or to a CO2-brine mixt ure.) In Crow et al (2009), a similar study was conducted on a CO2
p roduction well that was drilled into and completed in a natural CO2 producing formation. This study concluded that CO2 had caused alteration (carbonation) of the well cem ent and acidifica tion of fluids adjacent to the caprock. The study could not determin e if the alteration was due to exposure from CO2 diffusion up into the overlying caprock or by upward CO2 migration within wellbore system defects (perhaps cement-caprock and/or cement-formation interfaces). In both studies, the CO2 apparently moved from the underlying reservoir into the well bore section loca ted within the overlying caprock. These observations, especially in conjunction with the larger CO2 volumes and higher reservoir
p ressures anticipated with GS, justify the well construction requirements in the final GS rule in order to
p revent deterioration of the materi als between the well casing and th e well bore that can result in unacceptable fluid movement.

EPA adds that buoyancy of CO2 is am ong several unique considerations for large scale GS that warrant the tailored construction requirements at §146.86. For example, seismi c surveys at Sleipner showed that CO2 had migrated to the top of the 200 to 300 meter th ick formation as early as 3 years after injection b egan. The overall behavior of CO2 at Sleipner is for it to migrate to the top of the formation and spread laterally from there (Chadwick et al 2006). Additiona lly, CO2 has the potential to be corrosive (in the
p resence of water or aqueous formation fluids duri ng CO2 injection), and the volume of CO2 anticipated to be injected in Class VI well s is significantly greater than for Class II ER/ CO2 injection wells.

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost USDW Comment: The TxCCSA also comments on the definition of Geologic Seque stration Project referenced in this section.

Geologic sequestration proj ect means an injection we ll or wells used to emplace a carbon dioxide stream beneath the lowermost formation containing a USDW. It includes the s ubsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surface area above that delineated region.

This definition restricts geologic seque stration projects to the lowermost formation containing a USDW. Restricting injection formations to the lowermost USDW is not necessary for the protection of USDWs and would remove a vast number of viable formations from considerati on. The drilling industry has shown that it can operate CO2 in j ection wells in an e nhanced oil recover y (EOR) context Commenter Name: Darrick Eugene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture and Stora g e Association Comment ID: 23968without endangering USDWs that are locat ed below the injection zone. There should be no blanket prohibition against injection into any approved geologic zone even if above the lowermost USDW. The decision should be site-specific and based on evaluation of local geology. We fully support the change proposed by the Texas Railroad Commission in its comments.

Geologic sequestration proj ect means an injection we ll or wells used to emplace a carbon dioxide stream beneath the lowermost formation containing a USDW, OR ANOTHER FORMATION, IF THE DIRECTOR DETERMINES THAT INJECTION INTO THE OTHER FORMATION WI LL NOT ENDANGER USDWS. It includes the subsurface three- dimensional ex tent of the carbon dioxide plume, associated pressure front, and displace d brine, as well as the surface area above that delineated region.

Response: EPA acknowledges that there are limited circum stances where injectio n above the lowermost USDW can be performed in a manner that protects USDWs from endangerment, as long as appropriate
p rotections are in place. The fina l GS rule at §146.95 establishes a pro cess by which owners or operators can seek a waiver of the Class VI injection depth requirements for injection into non-USDW formations above and/or between USDWs. It establishes: 1) requirements specifying information that owners or operators must submit, and Director s must consider, in consultation wi th PWSS Directors; 2) procedures for public notice of a waiver application and for Di rector-Regional Administra tor communication; 3) the waiver issuance process; and, 4) a dditional requirements that apply to owners or operators of Class VI wells granted a waiver of the injection depth requir ements to ensure USDW protection above and below the injection zone.

EPA also revised the definition of a geologic sequestration project to account for the new requirements to include “wells used for geologi c sequestration of carbon dioxide that have been granted a waiver of the injection depth requirements pursuant to requirements at §146.95.”

EPA believes that these requirements will ensure USDW protection while provi ding flexibility to UIC
p rogram Directors and owners or operators who unde rtake CO2 injection for GS. The Agency believes this approach: 1) responds to concerns about local and regional geologic stor age capacity limitations imposed by the proposed injection de pth requirements; 2) allows for a more site-specific assessment of injection depth for GS projects; 3) accommodates injection into differen t formation types; 4) allows for injection of CO2 for GS into non-USDWs above and/or between USDWs when appropriate and where it can be demonstrated that USDWs will be protected; and 5) responds to concerns about the use of aquifer exemptions for GS. Finally, EPA’s approach to addressing injection depth variability through a waiver
p rocess responds to concerns about future drinking wate r resource availability and the need to ensure that high quality water remains available in suffici ent quantities to supply drinking water needs. For additional information on the waiver approach, please see the final rule and preamble, as well as EPA's responses to comments on the Notice of Data Availability and Request for Comment.

Comment: (iv) Definition of Carbon Dioxide Stream

Section 146.81 of the Proposed Rule defines "carbon dioxide str eam" as follows:

Carbon dioxide stream means carbon dioxide that has been captured from an emission source (e. g ., a power plant), plus incidental associated substances Commenter Name: Tiffan y Rau Letter ID: 0224 Commenter Or g anization: H y dro g en Ener gy International Comment ID: 21686derived from the source materials and th e capture process, and any substances added to the stream to enable or improve the injection process. This subpart does not apply to any carbon dioxide str eam that meets the definition of a hazardous waste under 40 CFR part 261.

By limiting the definition to "emission s ources," the Class VI regulations may have the unintended effect of narrowing th e types of sources th at might inject CO2 for geologic sequestration. The particular source of the CO2 is not material in terms of protecting USDW s. Furthermore, the Final Rule should not address the source because it is beyond the scope of this regulation. We recommend deleting the phrase “has been captured from an emission source (e.g., a power
p lant)” from the definition contained in section 146.81 of the Proposed Rule so that the Final Rule does not inadverten tly preclude other non-emission sources of CO2.

Response: EPA disagrees with the suggested edit. The fi nal definition of car bon dioxide stream at §146.81(d) remains unchanged and reads as follows: “[C]arbon dioxide that has been captured from an emission source (e.g., a power plant), plus incidental associated subs tances derived from the source materials and the capture process, and any substances added to the stream to enable or improve the injection process. This s ubpart does not apply to any carbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Comment: (iv) Definition of Carbon Dioxide Stream

Section 146.81 of the Proposed Rule defines "carbon dioxide str eam" as follows:

Carbon dioxide stream means carbon dioxide that has been captured from an emission source (e.g., a power plant), plus incidental associated substances derived from the source materials and th e capture process, and any substances added to the stream to enable or improve the injection process. This subpart does not apply to any carbon dioxide str eam that meets the definition of a hazardous waste under 40 CFR part 261.

By limiting the definition to "emission s ources," the Class VI regulations may have the unintended effect of narrowing th e types of sources th at might inject CO2 for geologic sequestration. The particular source of the CO2 is not material in terms of protecting USDWs. Furthermore, the Final Ru le should not address the source because it is beyond the scope of this regulation. We recommend deleting the phrase "has been captured from an emission source (e .g., a power plant)" from the definition contained in section 146.81 of the Proposed Rule so that the Final Rule does not inadvertently precl ude other non-emission sources of CO2.

Response: EPA disagrees with the suggested edit. The fi nal definition of car bon dioxide stream at §146.81(d) remains unchan g ed and reads as: “[C]arb on dioxide that has been captured from an emission Commenter Name: Brian Williams Letter ID: 0225 Commenter Or g anization: BP Alternative Ener gy North America, Inc. (BP) Comment ID: 21737source (e.g., a power plant), plus inci dental associated substances derived from the source materials and the capture process, and any substances added to the stream to enable or impr ove the injection process. This subpart does not apply to any carbon dioxide st ream that meets the defi nition of a hazardous waste under 40 CFR part 261.”

EPA clarifies that the Class VI GS requirements apply to owners or opera tors of injection wells that will be used to inject CO2 into the subsurface for the purposes of GS. The capture of CO2 is outside the scope of the final rule.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: 1. Schlumberger asks that the EPA expand th e applicability of Class VI wells to cover wells injecting CO2 th at is dissolved in water or brine. The current draft language for Section 146.81(b) states:

This subpart applies to wells used to inject carbon dioxide specifically for the purpose of geologic sequest ration, i.e., the long-term containment of a gaseous, liquid or s upercritical carbon dioxide stream in subsurface geol ogic formations.

We suggest that the EPA replace the cu rrent language with the following language:

This subpart applies to wells used to inject carbon dioxide specifically for the purpose of geologic sequest ration, i.e., the long-term containment of a gaseous, liquid or s upercritical carbon dioxide stream or carbon dioxide dissolved in water or brine into subsurface geologic formations.

While we recognize today the injection of dissolved CO2 raises economic challenges we feel that there may be cases where the injection of dissolved CO2 will make sense both in terms of econom ics and in terms of leakage risk. Unlike separate phase CO2, CO2 dissolved in water is not less dense than the formation fluid and will not be s ubject to buoyancy driven leakage.

Response: EPA disagrees with the suggested change. §146.81(b) reads as follows: “This subpart applies to any wells used to inj ect carbon dioxide specifical ly for the purpose of geologic sequestration, i.e., the long-term containment of a gase ous, liquid, or supercritical carbon dioxide stream in subsurface geologic formations.” Nothing in th e rule precludes the injection of dissolved CO2, as long as the CO2 does not meet the definition of a hazardous waste under 40 CFR part 261.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information. Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 23996Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: Proposed Rule: Carbon dioxide stream means carbon dioxide that has been captured from an emission source (e.g., a power plant), plus incidental associated substances derived from th e source materials and the capture process, and any substances added to the stream to enable or improve the injection process. This subpart does not apply to any carbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.

Schlumberger Suggested Revision:: Carbon di oxide stream carbon dioxide that has been captured from an indus trial process that is injected in any physical state or dissolved in water or brine. It includes incidental associated substances derived from the source materials and th e capture process, and any substances added to the stream to enable or improve the injection process. This subpart does not apply to any carbon dioxide str eam that meets the definition of a hazardous waste under 40 CFR part 261.

Schlumberger Rationale: We want to ensure that dissolved CO2 is specifically allowed as it may allow a solution to th e upward buoyancy drive associated with separate phase CO2.

Response: EPA disagrees with the suggested edit. The fi nal definition of car bon dioxide stream at §146.81(d) remains unchanged and reads as: “carbon dioxide that has be en captured from an emission source (e.g., a power plant), plus inci dental associated substances derived from the source materials and the capture process, and any substances added to the stream to enable or impr ove the injection process. This subpart does not apply to any carbon dioxide st ream that meets the defi nition of a hazardous waste under 40 CFR part 261.” As described above, nothing in the rule precludes the injection of dissolved CO2, as long as the CO2 does not meet the defi nition of a hazardous waste under 40 CFR part 261.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment EPA has made many revisions to the GS rule. Please see the final rule and
p reamble for additional information.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: Proposed Rule:Geologic sequestration mean s the long-term containment of a gaseous, liquid or supercri tical carbon dioxide stream in subsurface geologic formations. This term does not apply to its capture or transport.

Schlumberger Suggested Revision: Geologic sequestration means the long-term containment of a carbon dioxide stream in subsurface geologic formations. This term does not apply to its capture or transport.

Schlumber g er Rationale: CO2 stream was alread y defined and should e used here. Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24010

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24011Response: EPA disagrees with the suggested change. The final definition of ge ologic sequestration at §146.81(d) reads as follows: “[T]he long-term containment of a gaseous, liquid, or supercritical carbon dioxide stream in subsurface geol ogic formations. This term does not apply to carbon di oxide capture or transport.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: Proposed Rule: Geologic sequestration project means an injection well or wells used to emplace a carbon dioxide stre am beneath the lowermost formation containing a USDW. It includes the subsur face three-dimensional extent of the carbon dioxide plume, associated pressure front, and displa ced brine, as well as the surface area above that delineated region.

Schlumberger Suggested Revision: Geol ogic sequestration project means an injection well or wells used to em place a carbon dioxide stream into an injection zone. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displa ced brine, as well as the surface area above that delineated region.

Schlumberger Rationale: -

Response: The Agency has modified the definition of geologic sequestration project at §146.81(d) to read as follows: “Geologic sequest ration project means an injection we ll or wells used to emplace a carbon dioxide stream beneath the lo wermost formation containing a USDW; or, wells used for geologic sequestration of carbon dioxide that have been granted a waiver of the injection depth requirements
p ursuant to requirements at §146.95; or, wells used for geologic sequestration of carbon dioxide that have received an aquifer exemption expansion. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surface area above that delineated region.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: Proposed Rule: Injection zone means a ge ologic formation, group of formations, or part of a formation that is of suff icient areal extent, thickness, porosity, and permeability to receive carbon dioxide through a well or wells associated with a g eolo g ic sequestration pro j ect. Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24012

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24013Schlumberger Suggested Revision: Inject ion zone means a geologic formation, group of formations, or part of a formation that is of sufficient areal extent, thickness, porosity, and permeability to receive carbon dioxide through a well or wells associated with a geologic sequestration project.

Schlumberger Rationale: -

Response: EPA disagrees with the suggested edit. Th e definition of injection zone at §146.81(d) remains unchanged and reads as follows: “[A] geologi c formation, group of form ations, or part of a formation that is of sufficient areal extent, thickness, porosity, a nd permeability to receive carbon dioxide through a well or we lls associated with a geologic sequestration project.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: Proposed Rule: Pressure front means the zone of elevated pressure that is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressure differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.

Schlumberger Suggested Revision: Pressure front means the zone of elevated
p ressure that is created by the injecti on of the carbon dioxide stream into the subsurface, where there is a pressure diff erential sufficient to cause movement of the carbon dioxide stream or formation fluids into a USDW.

Response: EPA disagrees with the suggested edit. The final definition of pressure front at §146.81(d) is unchanged and reads as follows: “[T] he zone of elevated pressure th at is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressu re differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: Proposed Rule: Site closure the point/tim e, as determined by the Director following the requirements under §146.93, at which the owner or operator of a GS site is released from post-in j ection site care responsibilities. Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24014

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24015Schlumberger Suggested Revision: Site closure means the point/time, as determined by the Director following the requirements under §146.93, at which the owner or operator of a GS project is released from post-injection site care responsibilities.

Schlumberger Rationale: Sugge st using "GS project" to be consistent with other definitions

Response: EPA disagrees with the suggested edit. The final definition of site closure at §146.81(d) is unchanged and reads as follows: “The point/time, as determined by the Director following the requirements under §146.93, at which the ow ner or operator of a GS site is released from post-injection site care responsibilities.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: Proposed Rule: Transmissive fault or fract ure means a fault or fracture that has sufficient permeability and vertical exte nt to allow fluids to move between formations.

Schlumberger Suggested Revision: Transmissive fault or fracture means a fault or fracture that has sufficient permeability a nd vertical extent to allow fluids to move beyond the confining zone.

Schlumberger Rationale: The term between fo rmations is insuffic ient as it could also include multiple zones within a inj ection zone or between two zones above the confining unit.

Response: EPA disagrees with the suggested edit. The final definition of tran smissive fault or fracture at §146.81(d) is unchanged and reads as foll ows: “[A] fault or fra cture that has suffic ient permeability and vertical extent to al low fluids to move between formations.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost USDW Comment: 146.81(d) Geologic sequestration project sh ould be redefined as follows: Geologic sequestration project means an injection well or wells used to emplace a carbon dioxide stream into an in j ection zone for g eolo g ic sequestration. Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24016

Commenter Name: Mark Bohre r Letter ID: 0241 Commenter Or g anization: North Dakota Industrial Commission Comment ID: 23278Geologic sequestration projec ts should not be limited to beneath the lowermost formation containing a USDW.

Response: EPA has not revised the definition of a geol ogic sequestration project for the final rule. However, as described above, EPA acknowledges that there are limited circum stances where injection above the lowermost USDW can be performed in a manner that protects USDWs from endangerment, as long as appropriate protections ar e in place. The final GS rule at §146.95 establishes a process by which owners or operators can seek a waiver of the Cla ss VI injection depth requirements for injection into non-USDW formations above and/or between USDWs.

Other EPA Comment Codes and Descriptions: 3110 2.1.1 Proposed siting requirements (i.e., injection/confining zones, trapping mechanism) Comment: 146.82(a) Overlying formations needs to be defined. Geologic information should be limited to the injection and confining zones.

Response: EPA believes that a detailed geological si te characterization (r equired under §146.82) is essential to evaluating the presence and adequacy of the various geologic features necessary to receive and confine injected CO2 for GS. The requirements for geologic site characterization are based on a long standing UIC regulatory framew ork developed to address spec ific risks to USDWs posed by injection. The Class VI GS requirement s are tailored so that they are appropriate for the unique nature of injecting large volumes of CO2 into a variety of geological formations fo r long-term storage.

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators and Directors in evaluating permit requirements and applications under §146.82. The guidance provides recommendations regarding charac terizing the regional geology and hydr ogeology of a proposed GS site as well as performing the necessary geochemical, geomechanical, and geophys ical analyses of the injection and confining zone. The guida nce can be found on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: The definition of "carbon di oxide stream" should not be restricted to CO2 captured from industrial sources

The definition of "carbon dioxide stream" in §146.81( b) includes only carbon dioxide "that has been captured from an emission source (e.g., a power plant)." Over time, the vast majority of sequestered CO2 is likely to be captured from such sources, but rules are also needed to govern the sequestration of naturally occurring CO2 produced from geologic formations. We suggest that the definition be revised to read as follows:

[In the paragraph below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf , starting on p. 10, to see the original formatting.] Commenter Name: Mark Bohre r Letter ID: 0241 Commenter Or g anization: North Dakota Industrial Commission Comment ID: 23279

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22293"Carbon dioxide stream means that has been captured from an emission source (e.g., a power plant), carbon dioxide plus incidental associated substances derived from the source materials OF THE CO2 AND/OR the capture process, and any substances added to the stream to en able or improve the injection process. This subpart does not apply to any ca rbon dioxide stream that meets the definition of a hazardous wa ste under 40 CFR part 261."

Response: EPA disagrees with the suggested edit. The fi nal definition of car bon dioxide stream at §146.81(d) remains unchanged and reads as follows: “[C]arbon dioxide that has been captured from an emission source (e.g., a power plant), plus incidental associated subs tances derived from the source materials and the capture process, and any substances added to the stream to enable or improve the injection process. This s ubpart does not apply to any carbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: The definition of "confining zone" should not be limited to formations overlying the injection zone, and should focus on li miting movement through the confining zone rather than out the injection zone

The proposed definition of confining zone in §146.81(d) requires that the formation act as "a barrier" to fluid movement, which may be unnecessarily strict. The definition also fails to recognize that it is movement through and beyond the confining zone that needs to be limited. We suggest instead that the definition of "confining zone" read as follows:

[In the paragraph below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf to see the original formatting.]

"Confining zone means a geol ogic formation, group of form ations, or part of a formation stratigraphically overlying the injection zone that acts as a barrier to limit fluid movement beyond THIS FORMATION, GROUP OF FORMATIONS, OR PART OF A FORMATION."

Response: EPA disagrees with the suggested edit. Howe ver, the Agency has modified the final definition of confining zone at §146.81(d) to read as follows: “[A] geologic formation, group of formations, or part of a formation stratigraphically overlying the injection zone that acts as barrier to fluid movement. For Class VI wells operating under an injection depth waiver, confining zone means a geologic formation, group of format ions, or part of a formation stratigraphically overlying and underlying the injection zone.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made man y revisions to the Class VI GS rule. Please see the final rule Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22300and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1240 1.1.1.3 Suggested changes/edits to rule language

Comment: The second sentence of the definition of ‘geologic sequestration project" should be amended to refer more generally to form ation fluids and be transferred to the definition of "area of review"

We suggest the following amendment to §146.81(d) in order to be more inclusive on the types of fluid that could be displaced:

[In the paragraph below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf to see the original formatting.]

"[...] It includes the subsurface three-dimensional extent of the carbon dioxide
p lume, associated pressure front, and displaced brine FORMATION FLUIDS, as well as the surface area above that delineated region.

We also suggest that this second sent ence of the definition of geologic sequestration project be transferred to the definition of area of review as recommended above. The language provided a bove reflects the change from "brine" to "formation fluids."

Moreover, we suggest that the present re striction of Class VI to formations below the lowermost USDW is more appropria tely addressed elsewhere. Accordingly, we recommend that geologic sequestrati on project be defined as follows:

[In the paragraph below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf to see the original formatting.]

"Geologic sequestration project means an inj ection well or wells used to emplace a carbon dioxide stream beneath the lowermost formation containing a USDW INTO AN INJECTION ZONE FOR GEOLOGIC SEQUESTRATION. It includes the subsurface three

dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surfa ce area above that delineated region."

The term "pressure front" should be replaced with the more acc urate term "area of elevated pressure" throughout the rule

The term "pressure front" in 146.81(d) is like ly to be scientifically inaccurate as it implies a front, or discontinuity in pressure, whereas in reality there will be a continuous pressure gradient in the formation in most cases. We suggest globally replacing "p ressure front" with "area of elevated pressure" throughout the rule.

Response: EPA disa g rees with the su gg ested edit. However, the A g enc y has modified the definition of Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22301geologic sequestration project at §146.81( d) to read as follows: “Geo logic sequestration project means an injection well or wells used to emplace a carbon dioxide stream beneath the lowermost formation containing a USDW; or, wells used for geologic seques tration of carbon dioxide that have been granted a waiver of the injection depth requirements pursu ant to requirements at §146.95; or, wells used for geologic sequestration of carbon dioxide that have received an aquifer exemption expansion. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surface area above that delineated region.”

The final definition of pressure front at §146.81(d) also is unchanged and reads as follows: “[T]he zone of elevated pressure that is created by the injection of carbon dioxide into the subsurface. For the
p urposes of this subpart, the pressure front of a carb on dioxide plume refers to a zone where there is a
p ressure differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: The area of review provisions should be revised in several respects

Surprisingly, the definition of "area of review" (AOR) in §146.81(d) fails to mention that elevated pressure a critical aspect of what it means for an area to be "impacted" by injection activity. Our Environmental NGO Group recommends borrowing language from the proposed definition of "geologic sequestration
p roject" and reworking the "area of review" definition.

Response: Although EPA disagrees with the commenter's s uggested change, the Agency has carefully considered all comments on the AoR definition at 146.84( a) and modified it to read as follows: The region surrounding the geologic sequestration proj ect where USDWs may be endangered by the injection activity. The area of revi ew is delineated using computati onal modeling that accounts for the
p hysical and chemical propert ies of all phases of the injected CO2 stream and is based on available site characterization, monitoring, and operational data. EPA believes that this definition is sufficiently broad and describes both the intent of the computational modeling and the relationship of the AoR to areas that are subject to the risks associated with injection.

Other EPA Comment Codes and Descriptions: 3200 2.2 Proposed Area of Review and Corrective Action Requirements (40 CFR 146.84) Comment: Rule Provision: 146.81(d) Definitions

EPA Proposal: (d) Definitions. The following definitions apply to this subpart. To the extent that these defi nitions conflict w ith those in § 146.3 these definitions govern: Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22306

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24854Area of review means the region surroundi ng the geologic sequestration project that may be impacted by the injection act ivity. The area of review is based on computational modeling that accounts for the physical and chemical properties of all phases of the injected carbon dioxide stream.

GWPC Recommendations: Area of review m eans the subsurface three-dimensional extent of the carbon dioxide stream pl ume associated pressure front, and displaced brine, as well as the overlying formations a nd surface area above that delineated region.

Rationale: Suggest removal of the second sentence and replaceme nt with : "It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surface area above that delineated region."

Comment on the inclusion of the word "surrounding" because the AoR should be coextensive with the area defined by the Ca rbon Sequestration Project. Inclusion of "surrounding" makes this defi nition open-ended and ambiguous.

Response: Based on review of all public comments on th e AoR definition at 146.84(a), the Agency has modified it to read as follow s: The region surrounding the geologic sequestration project where USDWs may be endangered by the injection activity. The ar ea of review is delineat ed using computational modeling that accounts for the physical and chemical properties of all pha ses of the injected CO2 stream and is based on available site characterization, monitoring, and operational data. The definition in the
p roposed rule accounted for the varying physical a nd chemical properties of the CO2 including freep hase and wate r -dissolved CO2, as the commenter suggests. The definition in the final rule will continue to do so. EPA is developing guidance on AoR and corrective action at GS Class VI sites to assist owners or operators and Directors in evaluating requirements and proposed AoR and corrective action plans under 146.84. The guidance describes EPA's recommended appro aches for the data to be considered in an initial AoR delineation, how to apply computational modeling to delineate the AoR, performing corrective action at GS sites, and, when appropriate, completing Ao R reevaluations. The guidance will be available on EPA's web site, at http://water .epa.gov/type/groundwater/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 1630 1.3.3 RCRA/hazardous waste issues (seeking comment) Comment: EPA Proposal: Carbon dioxide plume mean s the underground extent, in three dimensions, of an injected carbon dioxide stream.

Carbon dioxide stream means carbon dioxide that has been captured from an emission source (e.g., a power plant), plus incidental associated substances derived from the source materials and th e capture process, and any substances added to the stream to enable or improve the injection process. This subpart does not apply to any carbon dioxide str eam that meets the definition of a hazardous waste under 40 CFR part 261.

GWPC Recommendations: Carbon dioxide stream means carbon dioxide, plus associated substances derived from the source materials and an y processin g , and Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24855any substances added to the stream to en able or improve the injection process. This subpart does not apply to any ca rbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.

Source of CO2 should not be an issue in the context of defining the CO2 stream.

Response: The final GS rule retains the definition of a CO2 stream as proposed. The GS regulation applies to injection of CO2 for the purpose of GS, regardless of the source of the CO2. It is beyond the scope of the GS rule and the UIC Program’s authority to require or set standards for upstream generators of CO2 or purification facilities. For purposes of GS, the UIC program’s authority under the SDWA is limited to ensuring that GS projects are sited, constructed, operate d, and closed in a manner that protects USDWs. The GS rule does not apply to generators of CO2. Additionally, EPA has received numerous comments regarding the applicabili ty of the RCRA regulations and statute to CO2 streams that are geologically sequestered under the fi nal Class VI UIC well requirement s. As a result, EPA has decided to initiate a separate proposed ru lemaking specifically to examine th e issue of RCRA applicability to CO2 streams being geologically sequestered, including the possible option of a conditional exemption from the RCRA requirements for CO2 GS in Class VI wells. EPA will consider these comments as part of its development of that proposal. The Agency will consider issues particular to RCRA in the context of that separate rulemaking, and recommends that th e commenter read that proposed rule when it is
p ublished. The Agency notes that co mmenters who wish to submit comments on the RCRA proposal will need to do so during the comment period for that rule. Finally, EPA also notes that the final GS rule, which adds new regulations for Class VI wells under the Safe Drinking Water Act (SDWA), is not making any changes to th e RCRA regulations.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rationale: Insert the definition "Computat ional modeling means a mathematical model that is appropriate to the site geometry and takes into account the differences between the format ion and injection fluids."

Response: The final rule does not define computationa l modeling. The preamble to the proposed GS regulation and the modeling background document "C omputational Modeling of Underground Injection of Carbon Dioxide for Determination of Area-of-Review and Potentia l Risk to Underground Sources of Drinking Water" (cited in the proposed rule preamble as USEPA, 2008d include FR citation) discuss, in detail, what EPA believes consti tutes a computational model. Appr opriate models may incorporate numerical, analytical, or semi-analy tical approaches. These models solve a series of governing equations to predict the composition and volumet ric fraction of each phase state, as well as fluid pressures, as a function of location and time for a particular set of conditions. EP A is developing guidance on AoR and corrective action at GS Class VI sites to assist owners or opera tors and Directors in evaluating requirements and proposed AoR a nd corrective action plans under 146.84. The guidance describes the data that EPA recommends to be considered in an initial AoR delineation, how to apply computational modeling to delineate the AoR, performing corrective action at GS sites, and, when appropriate, completing AoR reevaluations. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24856

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24857Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: EPA Proposal: Confining zone means a geol ogic formation, group of formations, or
p art of a formation stratigraphically overlying the inject ion zone that acts as a barrier to fluid movement.

GWPC Recommendations: Confining zone means a geological formation, group of formations, or part of a formation that is capable of limiting fluid movement from an injection zone.

Rationale: The current UIC program definition of confining zone is preferable to the proposed definition. There are no spec ial circumstances for CO2 streams that warrant a change

Response: EPA acknowledges the comment and the final ru le retains this text as proposed. EPA believes that the definitions used for injection zone and confining zone for Class VI GS are appropriately tailored to address the unique risk s and challenges posed by GS of CO2 streams.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: EPA Proposal: Corrective action means the us e of Director approved methods to assure that wells within the area of re view do not serve as conduits for the movement of fluids into underground sources of drinki ng water (USDW).

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the commenter’ s support; the final GS rule retains the definition.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: GWPC Recommendations: "Fault means a surface or zone of rock fracture along which there has [or has not] been displacement."

Rationale: Add definition of fault to clarify use in other provisions. This is the current definition with the inserti on of the words "or has not" before displacement to recognize that faults can exist where there has been no displacement.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Response to Comments EPA has made many revisi ons to the GS Rule. See the final rule and the discussion of site characterizati on in the preamble for further disc ussion on EPA's final approach. EPA does not define "fault" but define s "transmissive fault or fracture." EPA has retained the proposed definition, which is the same as the existing definition at §148.2, to a ddress transmissive faults and fractures that extend be y ond the confinin g zone. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24858

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24859Comment: EPA Proposal: Geologic sequestration mean s the long-term containment of a gaseous, liquid or supercri tical carbon dioxide stream in subsurface geologic formations. This term does not apply to its capture or transport.

GWPC Recommendations: Geologic sequestration means the long-term containment of a carbon dioxide stream in subsurface geologic formations. This term does not apply to its capture or transport.

Rationale: Suggest removing "gaseous, liquid or supercritical" as these terms are implied by the use of the term carbon dioxide.

Response: EPA disagrees with the suggested edit. However, the Agency has modified the definition of geologic sequestration at §146.81(d) to read as follows: “[T]he long-term containment of a gaseous, liquid, or supercritical carbon dioxide stream in subsurface geologi c formations. This term does not apply to carbon dioxide capture or transport.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost USDW Comment: EPA Proposal: Geologic sequestration project means an injection well or wells used to emplace a carbon dioxide stre am beneath the lowermost formation containing a USDW. It includes the subsur face three-dimensional extent of the carbon dioxide plume, associated pressure front, and displa ced brine, as well as the surface area above that delineated region.

GWPC Recommendations: Geologic sequestration project means an injection well or wells used to emplace a carbon dioxide stream into an injection zone for geologic sequestration.

Rationale: Replace "beneath the lowermost formation containi ng a USDW "with "into an injection zone"

Suggest moving the second sentence to the definition of AOR.

Response: In the final rule, EPA revised the definition of a geologic sequestration project to account for the new requirements to include “wells used for geol ogic sequestration of carbon dioxide that have been granted a waiver of the injection depth re quirements pursuant to requirements at §146.95.” Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24860

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24861

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24862Comment: GWPC Recommendation: Geologic sequestration site means

Rationale: The GWPC believes a definition for this term is needed as the term is referenced in later sections of the rule.

Response: EPA disagrees that a definition of geologic sequestration site is needed. EPA notes that a geologic sequestration site, under §146.83( a), comprises: “(1) An inject ion zone of sufficient areal extent, thickness, porosity, and permeability to receive the total anticipated volume of the carbon dioxide stream; [and] (2) Confining zones free of transmissive faults or fractures and of sufficient areal extent and integrity to contain the injected carbon dioxide stream and displaced formation fluids and allow injection at proposed maximu m pressures and volumes without in itiating or propa gating fractures in the confining zone(s).”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Comment: EPA Proposal: Injection zone means a geol ogic formation, group of formations, or
p art of a formation that is of sufficie nt a real extent, thickness, porosity, and permeability to receive carbon dioxide through a well or wells associated with a geologic sequestration project.

GWPC Recommendations: Injection zone m eans a geological "formation", group of formations, or part of a formation receiving fluids through a well.

Rationale: Existing definition in the CFR is sufficient and does not need to be changed. Furthermore, adding sufficiency is not a definitional issue and should be dealt with elsewhere.

Response: EPA disagrees with the suggested edit. The final definition of injection zone at §146.81(d) remains unchanged and reads as follows: “[A] geologi c formation, group of form ations, or part of a formation that is of sufficient areal extent, thickness, porosity, a nd permeability to receive carbon dioxide through a well or we lls associated with a geologic sequestration project.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA, and Request for Comment EPA has made many revisions to the GS rule. Please see the final rule and
p reamble for additional information.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: EPA Proposal: Post-injection site care means appropria te monitoring and other actions (including corrective action) needed following ces sation of injection to assure that USDWs are not endangered as required under § 146.93.

GWPC Recommendations: Post-in j ection site care means monitorin g and other Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24863

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24864actions (including correct ive action) following ces sation of injection, as required under 146.93.

Rationale: The definition should explain the meaning and not impose substantive requirements. These require ments are already addresse d in other sections.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Comment: EPA Proposal: Pressure front means the zone of elevated pressure that is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide pl ume refers to a zone where there is a pressure differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.

GWPC Recommendations: Pressure front means th e zone of elevated pressure that is created by the injection of the carbon dioxide stream into the subsurface, where there is a pressure differe ntial sufficient to cause movement of the carbon dioxide stream or formation fluids fr om the injection zone into a USDW.

Rationale: Proposal removes words that ar e unnecessary to provide clarity and would only serve to confuse.

Insert "from the injection zone" for clarification.

Response: EPA disagrees with the suggested edit. The final definition of pressure front at §146.81(d) is unchanged and reads as follows: “[T] he zone of elevated pressure th at is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressu re differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: EPA Proposal: Site closure the point/tim e, as determined by the Director following the requirements under § 146.93, at which the owner or operator of a GS site is released from post-inj ection site care responsibilities.

GWPC Recommendations: Site closure means the point/time, as determined by the Director following the requirement s under §146.93, at which the owner or operator of a GS pro j ect is released from post-in j ection site care Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24865

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24866responsibilities.

Rationale: Add "means"

Suggest using "GS project" to be c onsistent with other definitions

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: EPA Proposal: Transmissive fault or fracture means a fault or fracture that has sufficient permeability and vertical exte nt to allow fluids to move between formations.

GWPC Recommendations: Transmissive fault or fracture means a fault or fracture that has sufficient permeabil ity and vertical extent to allow fluids to move beyond the confining zone.

Rationale: Recommends changing "between formations" to "beyond the confining zone." The term between fo rmations is insufficient as it could also include multiple zones within a injection zone.

Response: EPA has retained the proposed definition, which is the same as the existing definition at §148.2, to address transmissive faults and frac tures that extend beyond the confining zone.

Other EPA Comment Codes and Descriptions: 4520 2.5.1 Continuous internal mechanical integrity monitoring (seeking comment) Comment: EPA (III. A. 4.) proposes "continuous monitoring" of various injection
p arameters.

- Staff believes "continuous monitori ng" is appropriate but that the
p recise definition of "continuous m onitoring" may be contentious.

Response: EPA agrees with the commenter regarding the importance of dem onstrating internal mechanical integrity (MI) and believes that cont inuous pressure monitoring to demonstrate internal mechanical integrity of Class VI wells is important, given the potential corrosive impact of CO2 and impurities on well materials, the pot ential geomechanical impacts to well integrity due to CO2 phase changes, and the temperature and pressure effects associated with injecti ng supercritical CO2. See §146.89(b). EPA also believes that the technology for continuous monitoring is practicable, available, and is currently in fairly wide use. EPA anticipate s that the owner or operato r’s testing and monitoring
p lan will describe the proposed specific equipment and recording frequency. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24867

Commenter Name: Steven Cheste r Letter ID: 0264 Commenter Or g anization: Michigan Department of Environmental Quality (MDEQ) Comment ID: 22842Other EPA Comment Codes and Descriptions: 4500 2.5 Proposed Mechanical Integrity Testing (MIT) Requirements (40 CFR 146.89) Comment: Definition of "Significant Leakage"

TFI requests that EPA define the term "significant leakage" in the context of mechanical integrity testing and quant ify amounts to avoid mi sinterpretations and to prevent de minimus CO2 leakage from falling under this term.

Response: A properly designed and operated well should have no leakage in the casing, tubing, or
p acker and no fluid movement into a USDW through channels adjacent to the wellbore. While the intent of MITs is to detect these types of problems as early as possible, the goal of the well design and construction requirements at §146.86 is the complete absence of such problems. EPA clarifies that the
p urpose of the "significant leakage" language in th is narrow context is simply to avoid triggering corrective actions for essentially de minimis situations. Determining whether a MIT result should trigger follow-up action is necessarily a case and site-specific situation; as a result, EP A does not believe it is appropriate to define the term "significant leakag e" in the context of MITs. In addition, EPA has not defined this term for purposes of other injection we ll classes and this has not been shown to hinder
p ermitting authorities' and owners or operators' abil ity to assess whether inject ion wells have adequate mechanical integrity. EPA believes that this approach allows states flexibility, will not interfere with the implementation of existing UIC programs, and maintains protection of USDWs from endangerment.

In keeping with its adaptive rulemaking approach, the Agency plans to collect and review data every six years on early GS projects, including MIT data, to determine whether the appropriate amount and types of information and appropriate docum entation are being collected, and to determine if modifications to the requirements are appropriate or necessary. For additional information, please see the discussion of MITs in the final rule preamble.

Other EPA Comment Codes and Descriptions: 4500 2.5 Proposed Mechanical Integrity Testing (MIT) Requirements (40 CFR 146.89) Comment: 146.89 Mechanical Integrity.

This rule uses the term "significant" in a number of places when describing leaks. There should be either a definiti on of "significant" or the wells should be adequately sealed so that there are no leaks.

Response: A properly designed and operated well should have no leakage in the casing, tubing, or
p acker and no fluid movement into a USDW through channels adjacent to the wellbore. While the intent of MITs is to detect these types of problems as early as possible, the goal of the well design and construction requirements at §146.86 is the complete absence of such problems. EPA clarifies that the
p urpose of the "significant leakage" language in th is narrow context is simply to avoid triggering corrective actions for essentially de minimis situations. Determining whether a MIT result should trigger follow-up action is necessarily a case and site-specific situation; as a result, EP A does not believe it is appropriate to define the term "significant leakag e" in the context of MITs. In addition, EPA has not defined this term for purposes of other injection we ll classes and this has not been shown to hinder
p ermitting authorities' and owners or operators' abil ity to assess whether inject ion wells have adequate mechanical inte g rit y . EPA believes that this appr oach allows states flexibilit y , will not interfere with the Commenter Name: William Herz Letter ID: 0266 Commenter Or g anization: The Fertilizer Institute Comment ID: 22883

Commenter Name: Donn Mille r Letter ID: 0270 Commenter Or g anization: State of Oregon, Water Resources Department Comment ID: 22888implementation of existing UIC programs, and maintains protection of USDWs from endangerment.

In keeping with its adaptive rulemaking approach, the Agency plans to collect and review data every six years on early GS projects, including MIT data, to determine whether the appropriate amount and types of information and appropriate docum entation are being collected, and to determine if modifications to the requirements are appropriate or necessary. For additional information, please see the discussion of MITs in the final rule preamble.

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment); 5280 2.8.2.4 USDW non-enda ngerment demonstrations Comment: (e) Concern exists regarding the need fo r (i) a standard (in concentration or saturation) for defining the edge of a CO 2 plume, (ii) clear definition of the term "stabilization" as applied to fate and transport of an injected CO2 plume and pressure front, and (iii) a clarifie d specification of the performance standard for the necessary demonstration to enable termination of the iterative
p rocess of monitoring/modeling and related corrective action. If "stabilization" means absence of plume movement or pressu re change, it is our understanding from CO2-GS research efforts that indefinite ly long periods of monitoring, modeling, and corrective action may be required in c ontrast to the default period of fifty years cited in the proposed rules and pr eamble. A more appropriate basis for demonstrations of protection of undergr ound sources of drinking water (USDW) would be keyed to the presence of induced pressure conditions in the injection zone, spatially and temporally. When a nd where such pressure conditions are insufficient to cause enda ngerment of a USDW through leakage pathways such as improperly constructed or plugged wells or transmissible faults, the required USDW protection should be considered to be present. Accordingly, if the termination of monitoring, modeling, and corrective action is ultimately dependent on making the subject demonstration, it is reco mmended that the "fifty year" specification be deleted from the rule. This would conform the requirements for post-injection site care fo r Class VI wells more closely to the
p ost-closure care specifications and concepts existing for Class I wells.

Response: EPA disagrees that the rule should specify the criteria for setting th e monitoring timeframe. Instead, EPA believes that such de terminations are site-specific and should be described in a project specific post-injection site care and site closure plan. EPA also be lieves that periodic reviews and updates, where necessary, to the plan are important to ensuring that the site continues to be managed effectively and to determine wh ether shortening the monitori ng timeframe is appropriate.

EPA acknowledges that many site-speci fic factors will influence the determination of when the CO2
p lume and pressure front no longer pos e a risk of endangerment to USDW s. It is for this reason that EPA believes that individual UIC Directors, in consultation with operators, will be in the best position to determine whether additional post-inje ction site care is needed. EPA e xpects this decision to be made based on relevant site data and in consultati on with all potentially impacted parties.

EPA agrees that a complete cessa tion of plume movement may not oc cur at some sites for long time
p eriods due to density diff erences, natural formation flow gradients and diffusion. EPA clarifies that a complete cessation of plume movement is not re quired, only a demonstration that the plume and
p ressure front no lon g er pose a risk of endan g erment to USDWs. Commenter Name: Mark Vicker y Letter ID: 0280 Commenter Or g anization: Texas Commission on Environmental Quality Comment ID: 24104EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirement s of 146.92 and 146.93. Additionally, the guidance will assist Directors in evaluating proposed well plugging plans and post-inject ion site care and site closure plans under 146.92 and 146.93. The guidance describes recommended approaches for how an owner or operator could plug injection and monitoring wells; perform post-injection moni toring; demonstrate non endangerment; and perform site closure activities. The guida nce will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Comment: • "Geologic sequestration" should not be defined only for the purpose of
p rotecting USDWs, but also for the pur pose of preventing re-emissions of injected carbon dioxide to the atmosphe re according to a defined permanence standard, as NRDC stated in its Dec24, 2008 comments;

Response: EPA clarifies that atmospheric emissions moni toring and quantification are outside the scope of the Class VI GS rulemaking. Th e UIC program’s authority under th e SDWA focuses on ensuring that GS projects are permitted, sited, c onstructed, operated, monitored, and closed in a manner that protects USDWs from endangerment.

In a separate rulemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Gas Reporting Program at 40 CFR Part 98 to add repor ting requirements for CO2 injection and geologic sequestration. The greenhouse gas repor ting requirements build on the Class VI requirements outlined in the final rule with the a dditional goals of verifying the amount of CO2 sequestered and collecting data on any CO2 emissions to the surfac e from Class VI GS facilities.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Comment: 3. Transmissive faults or fractures

The proposed rule in §146.83(a)(2) requires a confining zone(s) that is free of transmissive faults or fractures, while §146.81 defines this term as "A fault or fracture that has sufficient permeability a nd vertical extent to allow fluids to move between formations". We recomme nd the following modi fication to the definition in §146.81(d) in order to avoid unduly restricting move ment that is merely between formations:

"Transmissive fault or fracture means a fault or fracture that has sufficient
p ermeability and vertical extent to al low fluids to move beyond a confining zone."

Response: EPA disagrees with the suggested edit. The final definition of tran smissive fault or fracture at §146.81(d) is unchanged and reads as foll ows: “[A] fault or fra cture that has suffic ient permeability and vertical extent to allow fluids to move between formations.” Commenter Name: George Peridas Letter ID: 0291 Commenter Or g anization: Natural Resources Defense Council Comment ID: 25289

Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25310The confining zone definition at §146.83(a)(2) also is unchanged and reads as follows: “Free of transmissive faults or fractures and of sufficient areal extent and integrity to contain the injected carbon dioxide stream and displaced form ation fluids and allow injection at proposed maximum pressures and volumes without initiating or propagating fractures in the confining zone(s).”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: 4. Definition of confining zone

The proposed definition of confining zone in §146.81(d) requires that the formation act as "a barrier" to fluid movement, which may be unnecessarily strict. The definition also fails to recognize that it is movement through and beyond the confining zone that needs to be limited. We recomm end retaining the current UIC program definition of confini ng zone as preferable to the proposed definition with one revision to address th e possibility that a confining zone for a particular project may be beneath rather than above the injection zone.

"Confining zone means a geol ogical formation, group of form ations, or part of a formation that is capable of limiting flui d movement from an injection zone."

Response: EPA acknowledges the comment and disagrees that the definition of confining zone is too strict. EPA clarifies that §146.83(a) re quires that any GS project must ha ve at least one confining zone (i.e., impermeable layer) between the injection zone and the lowerm ost USDW. EPA further believes that, in some situations, the pres ence of additional confining and c ontainment zones above the primary (i.e., lowermost) confining zone can improve USDW protection. These layers could further impede vertical fluid movement and allo w for pressure dissipation, and al so provide additional sites for monitoring, mitigation, and remediation.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: 5. Area of review definition and basis

We also suggest that the second sentence of the proposed definition of GS
p roject be transferred to th e definition of area of review as recommended below. This language also reflects a change from "brine" to "formation fluids."

"Area of review means the subsurface th ree-dimensional exte nt of the carbon dioxide stream plume and the associated pressure front, as well as the overlying formations, [any USDWs underlying an inject ion zone along with any intervening formations,] [FN2] and the surface area above that delineated re g ion." Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25312

Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25313[FN2] The bracketed language should be included to the extent that the regulations authorize GS a bove USDWs, an issue on which the signatories have expressed differing views in our respecti ve comments on the proposed rule. See footnote 1 above.

In addition, we recommend that the se cond sentence included both in EPA’s
p roposed definition of area of review and in secti on 146.84(a) be dropped from the definition and retained in secti on 146.84(a) but modified to read as follows:

"(a) The area of review is based on computational modeling, as well as monitoring and other operational data, that account for the physical and chemical properties of all phases of the injected carbon dioxide stream."

The first sentence of section 146.84(a), wh ich duplicates the de finition of area of review, should be deleted from s ection 146.84(a) and retained in the definition with the modifi cations presented above.

Response: EPA disagrees that the AoR definition needs to specifically include th e overlying formations and surface area above the delineated region. The intent of the Ao R, a long-standing concept within the UIC Program, is to delineate the surface area and all subsurface formations below it that may potentially be impacted by injection activity. A cceptable delineation models will provide predictions of CO2 fate and transport, as well as changes in formation pressu re, in three dimensions as a function of time that can be used to delineate the subsurface storage site and the AoR.

Although EPA disagrees with the commenter's suggested change, the Agency has carefully considered all comments on the AoR definition at 146.84(a) and modified it to read as follows: The region surrounding the geologic sequestrati on project where USDWs may be endangered by the injection activity. The area of review is delineated using computational mo deling that accounts for the physical and chemical properties of all phases of the inj ected CO2 stream and is based on available site characterization, monitoring, and operational data. EPA believes that this definition is sufficiently broad and describes both the intent of the computational modeling and the relationship of the AoR to areas that are subject to the risks associated with injection.

Comment: We're pleased that the definition of zone of elevated pressures, Section 146.81 focuses both on the pressure that would drive CO2 through a confining zone, and also on the pressures that would dr ive fluid to a confining zone.

Response: The Agency acknowledges the comment. The fi nal definition of pre ssure front at §146.81(d) is unchanged, and reads as follows: “[T]he zone of elevated pressure that is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressu re differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information. Commenter Name: Scott Anderson Letter ID: 0510 Commenter Or g anization: Environmental Defense Fun d Comment ID: 21220Comment Code: 1230 1.1.1.2 General comments on the regulatory text



### Individual Comments

Comment: 146.82 (b): This will be an onerous task based on the proposed definition of AoR. Not necessary if the pressure fr ont is calculated or determined.

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: G. VAGUE LANGUAGE AND DE FINITIONAL PROBLEMS

There are many words and phrases in the draft regulations that are not well defined, and the meaning of which ought to be expanded upon. For instance, what might constitute "significan t leakage" in the context of mechanical integrity testing should be identified.

Response: A properly designed and operated well should have no leakage in the casing, tubing, or
p acker and no fluid movement into a USDW through channels adjacent to the wellbore. While the intent of MITs is to detect these types of problems as early as possible, the goal of the well design and construction requirements at §146.86 is the complete absence of such problems. EPA clarifies that the
p urpose of the "significant leakage" language in th is narrow context is simply to avoid triggering corrective actions for essentially de minimis situations. Determining whether a MIT result should trigger follow-up action is necessarily a case and site-specific situation; as a result, EP A does not believe it is appropriate to define the term "significant leakag e" in the context of MITs. In addition, EPA has not defined this term for purposes of other injection we ll classes and this has not been shown to hinder
p ermitting authorities' and owners or operators' abil ity to assess whether inject ion wells have adequate mechanical integrity. EPA believes that this approach allows states flexibility, will not interfere with the implementation of existing UIC programs, and maintains protection of USDWs from endangerment.

The final definition of mechanical integrity is unchanged. EPA clarifies that mechanical integrity is defined at §146.89(a) as the absence (1) of significant leak in the casing, tubing, or packer and (2) of significant fluid movement into a USDW through channels adjacent to the injection wellbore.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information. Commenter Name: Michael H. Cochran Letter ID: 0108 Commenter Or g anization: Bureau of Water, Division of Environment, Kansas Department of Health & Environment (KDHE) Comment ID: 21962

Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23820

Commenter Name: Edward Steadman Letter ID: 0220Comment: Page 43498. The example cited here (Crystal Geyser, Utah) is not associated with an "injection activ ity." It is naturally occurr ing CO2 that leaks via an improperly abandoned e xploration well.

Response: EPA agrees with the commenter that the Crystal Geyser site is not associated with injection. However, this incident demonstrates that abandoned or improperly plugged boreholes can serve as conduits for migration of fluids to USDWs. It is for this reason that the final rule includes requirements related to performing corrective action on all de ficient wells within the AoR at §146.84, and proper injection well construction th at meets the goals of §146.86.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: (E) ISSUES SPECIFICALLY RELATED TO OIL & GAS PRODUCTION

EPA has appropriately restricted the applicability of Class VI regulations to
p rojects that are exclusively geologic se questration projects. Furthermore, BP appreciates EPA’s efforts to limit this rulemaking to the authority vested in EPA by Congress pursuant to the Safe Drinking Water Act ("SDWA "). BP requests that EPA include some of the discussion in the Preamble to the Final Rule to ensure that unrelated activities in th e Oil & Gas industry are not impacted by unintended inferences or interpre tations of the Proposed Rule.

Response: EPA clarifies that the final Class VI regulations require that any owner or operator injecting CO2 for the primary purpose of long term storage obtain a Class VI permit with some special consideration for the fact that they are transitioning from a well not originally designed to meet Class VI requirements. The Director has the au thority to determine at what point a Class VI permit is required for those projects that are transitioning from the primary purpose of EOR to long term stor age of CO2. The final regulation provides a set of technical factors for the Direct or to evaluate in making this determination, at §144.19. EPA believes that this appr oach provides sufficient protection of USDWs when there is an increased risk to USDWs as compar ed to traditional Class II operations while allowing for site-specific flexibility. For more information, please see the di scussion on transition of Class II wells in the preamble to the final GS rule.

EPA recognizes that the oi l and gas industry has decades of experi ence injecting CO2 for the purpose of ER, and that sites used for ER may be suitable for GS and may be among the first GS sites. EPA also believes that the nature and risk s of CO2 injection for the primary purpose of long term storage poses different risks than injection for the primary purpose of ER, and ther efore has developed new Class VI regulations to address these unique risks. For example, the volume of CO2 anticipated to be injected for long term storage is significantly greater than for ERoperations. Reservoir pressure conditions will also b e different, with Class VI injection operations involving large volumes of CO2 and likely having higher
p ressures within their storage format ions than Class II ER projects.

Comment Code: 1240 1.1.1.3 Suggested changes/ed its to rule language Commenter Or g anization: The Energy and Environmenta l Research Center at the Universit y of North Dakota Comment ID: 21587

Commenter Name: Brian Williams Letter ID: 0225 Commenter Or g anization: BP Alternative Ener gy North America, Inc. (BP) Comment ID: 21759

### Individual Comments

Other EPA Comment Codes and Descriptions: 2048 1.5.2.4 Oppose Class VI/ Support Class V experimental technology well Comment: 144.18: Should be reworded along the lines of: upon the effective date of these regulations, new Class V wells must obtain a permit prior to construction.

Response: EPA clarifies that any owner or operator seeking to construct an injection well must obtain a
p ermit before beginning inj ection, but not necessarily the constructi on of the well. Owners and operators of Class VI wells for long-term sequestration or Class V experimental technology wells (for experimental GS projects) must submit information about the well, the geology of the site, and the
p lanned injection to demonstrate to the Director that the project wi ll be operated in a manner that
p rotects USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: Geologic sequestration project means an injection well or wells used to emplace a CO2 stream beneath the lowermost formation containing a USDW, OR ANOTHER FORMATION, IF THE DIRECTOR DETERMINES THAT INJECTION INTO THE OTHER FORMATION WILL NOT ENDANGER USDWS. It in cludes the subsurface 3-D extent of the carbon dioxide plume, asso ciated pressure front, a nd displaced brine, as well as the surface area above that delineated region.

{RRC suggests adding to the end of the first sentence of the definition of Geologic sequestration project, "or a nother formation, if the Director determines that injection into the othe r formation will not endanger USDWs." }

Response: EPA disagrees with the suggested edit. Howe ver, the Agency has modified the final definition of geologic sequestration project at §146.81(d) to read as fo llows: “[A]n injection well or wells used to emplace a carbon di oxide stream beneath the lowermost formation containing a USDW; or, wells used for geologic sequestration of carbon dioxide that have been granted a waiver of the injection depth requirements pursuant to requirements at §146.95; or, wells used for geologic sequestration of carbon dioxide that have received an aquifer exem ption expansion. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surfa ce area above that delineated region.”

EPA adds that the final rule contai ns a new provision for owners or operators to seek a waiver from the injection depth requirements, at §146.95. Based on its evaluation of all public comments and input on the proposed rule and the Notice of Data Availabi lity and Request for Comment, EPA has made many revisions to the Class VI GS rule . Please see the final rule and prea mble for additional information. Commenter Name: Michael H. Cochran Letter ID: 0108 Commenter Or g anization: Bureau of Water, Division of Environment, Kansas Department of Health & Environment (KDHE) Comment ID: 21959

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24759

Commenter Name: Leslie Savage Letter ID: 0122Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: Transmissive fault or fracture means a fault or fracture that has sufficient
p ermeability and vertical extent to allo w fluids to move between formations.

{Recommend that the fault or fracture be "known."}

Response: EPA disagrees with the suggested edit. The final definition of tran smissive fault or fracture at §146.81(d) is unchanged and reads as foll ows: “[A] fault or fra cture that has suffic ient permeability and vertical extent to al low fluids to move between formations.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: (2) Location, orientation, a nd properties of known or suspected faults and fractures that may trans ect the confining zone(s) in the area of review and a determination that they would not interfere with containment;

(4) Data on the depth, areal extent , thickness, mineralogy, porosity,
p ermeability and capillary pressure of the injection and confining zone(s) ; including geology/facies changes based on field data which may include geologic cores, outcrop data, seismic surveys, well logs, and names and lithologic descriptions;

Response: EPA believes that the plural fo r injection zone(s) should be re tained in the Final Rule in recognition of the fact that more than one injection zone may be used at some GS sites. EPA believes that in some geologic settings, th e presence and identification of a dditional confining and containment zones above the primary (i.e., lowermost) confining zone can improve USDW protection. These formations could further impede vertical fluid m ovement, allow for pressure dissipation, and provide additional sites for monitoring, mitigation, and remedi ation, while also affording the greatest protection of USDWs from endangerment. While other countries may not require such additional protection, EPA b elieves that providing the Director th is additional discretion is an impor tant element of assuring that GS activities will not endanger USDWs.

Please see the final rule and the discussion of geologic site characteriza tion in the preamble for additional information.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: (e) A tabulation of all wells within the AOR which penetrate the injection or confining zone(s) . Such data must include a desc ription of each well's type, construction, date drilled, lo cation, depth, record of plu gg in g and/or Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24761

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24762

Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24763completion, and any additional inform ation the Director may require;

{Definition of confining zone incl udes multiple formations. Do not imply that multiple confining zone s are preferable to one (good) confining zone.}

Response: EPA disagrees with the suggested edit. The final language in §146.82 is unchanged. EPA retains the requirement to identify additional containment/confining zones, if required by the Director, as proposed in §146.83(b). EPA acknowledges that such additional zones may not be needed in all circumstances, and clar ifies that this requirement is at the Director's discretion, based on his or her understanding of a particular site. EP A believes that, in some situat ions, the presence of additional confining and containment zones above the primar y (i.e., lowermost) confining zone can improve USDW protection. These layers coul d further impede vertical fluid movement and allow for pressure dissipation, and also provide additi onal sites for monitoring, mitigati on, and remediation. The Agency's decision is supported by commenters re presenting states, wate r associations, and an electric utility who assert that these requirements promote a flexible, risk -based, site-specific appro ach to characterizing and
p ermitting a site for GS projects, and would im prove understanding of the project as a whole and
p romote better modeling of the site.

Additionally, the Agency has modified the final definition of confining zone to read as follows: “[A] geologic formation, group of formations , or part of a formation strati graphically overlying the injection zone that acts as barrier to fluid movement. Fo r Class VI wells operating under an injection depth waiver, confining zone means a geologic formation, group of format ions, or part of a formation stratigraphically overlying and unde rlying the injection zone.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: (f) Maps and stratigraphic cross sections indicating the gene ral vertical and lateral limits of all USDWs, water wells a nd springs within the area of review, their positions relative to the injection zone(s) and the direction of water movement, where known;

{Consistency with definition and use of term in other areas of the rules.}

Response: EPA believes that the plural fo r injection zone(s) should be re tained in the Final Rule in recognition of the fact that characterizing more than one injection zone may be necessary at some GS sites. EPA believes that in some geologic settings, the presence and identification of additional confining and containment zones above the primary (i.e., lowermost) confining zone can improve USDW
p rotection. These formations could further impede vertical fluid movement, allow for pressure dissipation, and provide additional sites for moni toring, mitigation, and re mediation, while also affording the greatest protection of USDWs from endangerment. EPA believes that providing the Director this additional di scretion is an important element of as suring that GS activities will not endanger USDWs. Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24764Please see the final rule and the discussion of geologic site characteriza tion in the preamble for additional information.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82); 4710 2.7.1 Propos ed submissions required for permit applications (seeking comment) Comment: (i) The compatibility of the CO2 stream wi th fluids in the injection zone and minerals in both the injecti on and the confining zone(s) , based on the results of the formation testing program , and with the materials used to construct the well;

{See comment above.}

Response: The final rule will allow the Director to requi re more than one confining zone; therefore, EPA did not make the suggested change.

Please see the final rule and the discussion of geologic site characteriza tion in the preamble for additional information.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82); 4710 2.7.1 Propos ed submissions required for permit applications (seeking comment) Comment: (m) Proposed procedure to outline steps necessary to conduct injection operation;

{"Proposed procedure to outline steps" doe s not make sense. Recommend "Outline of steps ...."}

Response: EPA disagrees that the suggested edit provide s more clarity to the requirements and has retained the language as proposed. A dditionally, similar language is used for other UIC well classes and the regulated community and permitting officials are fa miliar with the terms.

Please see the final rule and the discussion of geologic site characteriza tion in the preamble for additional information.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: (1) An injection zone of sufficient areal extent, thickness, porosity, and
p ermeability to receive the total anti cipated volume of the carbon dioxide stream;

{Redundant - simply repeats the definiti on of "injection zone." Either take this language out of the definiti on or take it out of here.} Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24765

Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24766

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24767Response: EPA acknowledges the comment. For consiste ncy, §146.83(a)(1) includes the definition of injection zone. EPA clarifies that §146.83 identifies the specific criteria that owners or operators must meet to demonstrate that a GS site is suitable for GS.

Other EPA Comment Codes and Descriptions: 3110 2.1.1 Proposed siting requirements (i.e., injection/confining zones, trapping mechanism) Comment: (2) A confining zone(s) that is free of transmissive faults or fractures and of sufficient areal extent and integrity to contain the injected carbon dioxide stream and displaced formation fluids a nd allow injection at proposed maximum
p ressures and volumes without initiati ng or propagating fractures in the confining zone(s) ; and

{Redundant. Repeats definiti on of "confining zone." Al so, implies that the confining zone cannot have a single fracture, no matter how small. Much more stringent than for Clas s I hazardous wells.}

Response: EPA believes that the plural fo r injection zone(s) should be re tained in the Final Rule in recognition of the fact that characterizing more than one injection zone may be necessary at some GS sites. EPA believes that in some geologic settings, the presence and identification of additional confining and containment zones above the primary (i.e., lowermost) confining zone can improve USDW
p rotection. These formations could further impede vertical fluid movement, allow for pressure dissipation, and provide additional sites for moni toring, mitigation, and re mediation, while also affording the greatest protection of USDWs from e ndangerment. While other c ountries may not require such additional protection, EPA believes that providi ng the Director this additional discretion is an important element of assuring that GS activities will not endanger USDWs.

Other EPA Comment Codes and Descriptions: 3120 2.1.2 Need to identify additional confining and containment zones (seeking comment) Comment: (b) At the Director's discretion, owners or operators of Class VI wells must identify and characterize additional z ones that will impede vertical fluid movement, are free of faults and fractures that may in terfere with containment, allow for pressure dissipation, and provide additional opportunities for monitoring, mitigation and remediation.

{Redundant and unnecessary. Language in definition of "confining zone."}

Response: EPA retains the requirement to identify additi onal containment/confining zones, if required by the Director, as proposed (§146.83(b)). EPA acknowledges that such additional zones may not be needed in all circumstances, and clarifies that this requirement is at the Di rector's discretion, based on his or her understanding of a particular site. EPA beli eves that, in some situations, the presence of additional confining and containment zones above th e primary (i.e., lowermost) confining zone can improve USDW protection. These laye rs could further impede vertical fluid movement and allow for
p ressure dissipation, and also provi de additional sites for monitori ng, mitigation, and remediation. The Agency's decision is supported by commenters represen ting states, water associat ions, and an electric utilit y who assert that these require ments promote a flexible, ris k

- b ased, site-specific approach to Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24768

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24769characterizing and permitting a site for GS project s, and are intended to improve understanding of the
p roject as a whole and promote better modeling of the site.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: §146.84 Area of review and corrective action.

(a) The area of review is the region surrounding the geologic sequestration
p roject that may be impacted by the injection activity. The area of review is based on computational modeling that acc ounts for the physical and chemical
p roperties of all phases of the in jected carbon dioxide stream.

{Redundant - same as the defini tion of "area of review."}

Response: Based on review of all public comments on th e AoR definition at 146.84(a), the Agency has modified it to read as follow s: The region surrounding the geologic sequestration project where USDWs may be endangered by the injection activity. The ar ea of review is delineat ed using computational modeling that accounts for the physical and chemical properties of all pha ses of the injected CO2 stream and is based on available site characteri zation, monitoring, and operational data.

Other EPA Comment Codes and Descriptions: 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: (b) The owner or operator of a Class VI we ll must prepare, maintain, and comply with a plan to delineate the AOR for a proposed geologic sequestration project,
p eriodically reevaluate the delineation, and perform corrective action that meets the requirements of this section AT A FREQUENCY AND IN A MANNER THAT and is acceptable to the Director. As a part of the permit application for approval by the Director , the owner or operator must submit an area of review and corrective action plan that includes the following information:

Response: EPA disagrees with the suggested change, a nd is retaining the approach of setting a minimum fixed frequency for reevaluating the AoR but has, based on commenters' input, changed the frequency from 10 years to at least every 5 year s, as specified in §146.84(e). EPA agrees with commenters that site-specific information is an im portant factor in deter mining an appropriate AoR reevaluation frequency, and adds that the owner or operator's AoR and corrective action plan must describe the minimum fixed frequency for reeval uating the AoR and the site-specific conditions on which this frequency is based. EPA adds that the Dire ctor will evaluate the proposed plan in connection with a review of a vast amount of geologic and proposed operating da ta in determining whether to approve the plan. EPA is developing guidance on re commended approaches for preparing all of the required GS project plans, which will address c onsiderations for determin ing an appropriate AoR reevaluation schedule. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm. Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24770

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24771

Commenter Name: Leslie Sava g e Letter ID: 0122Other EPA Comment Codes and Descriptions: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment); 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: (2) A description of: (i) The minimum fi xed frequency, not to exceed 10 years, the owner or operator proposes to re evaluate the area of review; (ii) The monitoring and operational conditions that would warrant a reevaluation of the area of review prior to the next sche duled reevaluation as determined by the minimum fixed frequency established in paragraph (b)(2)(i) of this section.

{Suggest that there be no minimum fixed frequency for reevaluation of the AoR, but that such review be based on site-specific circumstances. }

Response: EPA believes that periodic AoR reevaluation at a set frequency of at least every 5 years is necessary to ensure protection of USDWs from endang erment and address the un certainties inherent in
p redictive modeling. Periodic AoR reevaluations at §146.84(e) ensure that a deliberate effort is made to verify, based on monitoring and operational data, that the CO2 plume is moving within the subsurface as
p redicted. EPA believes that less frequent reevaluations may not be su fficient to appropriately model
p lume and pressure front movement , establish conditions for corrective action, and ensure protection of USDWs from endangerment.

EPA clarifies that if site monitoring data agrees with the existing AoR delineation, a model recalibration may not be necessary, and the AoR reevaluation may consist of a demonstration that the current AoR delineation is adequate base d on site monitoring data.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action; 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: (II)(iii) How monitoring and operational da ta (e.g., injection rate and
p ressure) will be used to inform an area of review re evaluation; and

(iv) How corrective action will be conducted to meet the requirements of
p aragraph (d) of this section, including what corrective action will be
p erformed prior to injection and what, if any, portions of the area of review will have corrective action addressed on a phased basis and how the phasing will be determined; how corrective action will be adjusted if there are changes in the area of review; and how THE site WILL BE acc essed will be guaranteed for future corrective action.

{Word Choice. Secure rather than guarantee. }

Response: The purpose of the corrective action requirement at §146.84(d) is to ensure that all wells in the AoR that have the potential to cause the movement of CO2 or other fluids into or between USDWs receive appropriate correctiv e action. In general, to meet this re quirement, the owner or operator will mostly likely need to obtain the right of acces s to wells that may require corrective action, and demonstrate they have done this in their proposed Ao R and corrective action pl an. For this reason, the owner or operator must describe in the AoR and corrective action plan how site access will be guaranteed for future corrective action, as specifie d in §146.84(b)(2)(iv). The final rule retains the requirement as proposed. Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24772

Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24773Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: (1) Predict, using computational modeling, the projected lateral and vertical migration of the carbon dioxide plume and formation fluids in the subsurface from the commencement of in jection activities until th e plume movement ceases,
p ressure differentials sufficient to cause the movement of injected fluids or formation fluids into a USDW are no longer present, or FOR after a fixed time period as determined by th e Director. The modelINGmust:

Response: EPA has clarified this language in the final rule . It now reads, “Predi ct, using existing site characterization, monitoring and operational data, and computational modeling, th e projected lateral and vertical migration of the carbon dioxide plume and formation fluids in the subsurface from the commencement of injection activities until the plum e movement ceases, until pressure differentials sufficient to cause the movement of injected fluids or formation fluids into a USDW are no longer
p resent, or until the end of a fixed time period as determined by the Director.”

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: (i) Be based on detailed geologic data co llected to characterize the injection zone AND, confining zone and any additional zones ; and anticipated operating data, including injection pressures, rates and total volumes over the
p roposed life of the geologic sequestration project; (ii) Take into account RELEVANT any geologic heterogeneities AND, data quality, and their possible impa ct on model predictions; and (iii) Consider potential migration through KNOWN faults, fractures, and artificial penetrations.

Response: The final rule retains this requirement as proposed, except that 146.84(c)(1)(ii) also requires owners or operators to take into account other disc ontinuities in addition to geologic heterogeneities.

EPA disagrees that only the injection and confini ng zones should be included in AoR modeling of GS sites. EPA believes that the modeling should also take into account the possibility of displaced fluids or brines caused by a lateral and/or ve rtical pressure plume, and theref ore it may be necessary to include additional zones along with the confin ing/injection zones to ensure the integrity of the confining zone and ultimately protect a US DW from endangerment.

Other EPA Comment Codes and Descriptions: 3420 2.2.2.1 Scope of the inventory process (e.g., reliance on publicly available in formation, depth of wells) Comment: (2) Using methods approved by the Direct or, identify all KNOWN ARTIFICIAL
p enetrations THROUGH THE CO NFINING ZONE, including active and abandoned wells and underground mines, in the area of revi ew that may penetrate the confining

zone . Provide a description of each well's type, construction, date drilled, location, depth, record of plu gg in g and/or completion, and an y additional Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24774

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24775

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24776information the Direct or may require; and

Response: EPA is retaining this requirement as proposed. EPA agrees with commenters that, for most GS sites, relying on database and ot her public records searches (i.e., of "known" artificial penetrations) will be sufficient to meet the requirements at §146.84(c)(2). However, the Agency recognizes that there may be situations where additional surveys or research to locate wells may be appropriate. For example, there may be cases where the Dire ctor may determine that ground or airborne surveys for wells are appropriate, e.g., if there is reason to believe, based on knowledge of the site or of available data, that the incompleteness of information on known well s could compromise USDW protection from endangerment. In order to preserve the Director's discretion to re quire an operator to supplement a records search, EPA did not make the suggested change.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: (3) Determine which abandoned wells in th e AOR have been plugged in a manner that prevents the movement of CO2 or FORMATION associated fluids that may endanger USDWs.

Response: EPA clarifies that the term "associated fluids" as proposed in §146.84(c)(3) refers to formation fluids, other injectates, et c. that may be present in the subs urface and affect movement of the CO2 plume and/or pressure front. EPA believes this terminology woul d incorporate any fluids in the subsurface that could potentially move through artificial penetrations and affect USDWs. EPA has revised the language at §146.84(c)(3) to read, "... ca rbon dioxide or other fl uids that may endanger USDWs..."

Other EPA Comment Codes and Descriptions: 3460 2.2.2.3 Acceptable correct ive action techniques for GS sites (e.g., cements) Comment: (d) Owners or operators of Class VI wells must perfor m corrective action USING CORROSION RESISTANT MATERIAL, WHEN APPR OPRIATE, on all wells IDENTIFIED IN §146.84(C)(2) in the AOR that are determin ed to need corrective action using methods necessary to prevent the moveme nt of fluid into or between USDWs including use of corros ion resistant material s, where appropriate.

Response: EPA revised the text at §146.84(d) to require the use of materials that are "compatible with the carbon dioxide stream." EPA beli eves this language change addresses commenters' concerns and is also consistent with other language regardi ng materials requirements in the GS rule.

Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment) Comment: (f) At the minimum fixed frequency, not to exceed 10 years, as AS specified in the AOR and corrective action pla n, or when monitoring and operational conditions warrant, the ow ner or operator must: Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24777

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24778

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24779Response: EPA believes that periodic Ao R reevaluation at a set frequency is necessary to ensure
p rotection of USDWs from endangerment and address the uncertainties inherent in predictive modeling. Periodic AoR reevaluations at §146.84(e) ensure that a deliberate effort is made to verify, based on monitoring and operational data, that the CO2 plume is moving within the subsurface as predicted. EPA believes that less frequent reevaluations may not be sufficient to appropriately model plume and
p ressure front movement, establish conditions for corrective ac tion, and ensure pr otection of USDWs from endangerment.

EPA clarifies that if site monitoring data agrees with the existing AoR delineation, a model recalibration may not be necessary, and the AoR reevaluation may consist of a demonstration that the current AoR delineation is adequate base d on site monitoring data.

Based on the comments received (including thos e by water associations, an energy company, associations, industries, states, and environmental groups), EPA ha s changed the minimum frequency for the AoR reevaluation from 10 years to at least every 5 years. EPA believes that this revised frequency addresses commenters' concerns about the inherent uncerta inties in modeling CO2 movement, the emerging nature of GS technology, risk-based ta rgeting of monitoring activities, and the unique nature of CO2 GS.

Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment) Comment: (4) Submit an amended AOR and corrective action plan or demonstrate to the Director through monitoring data and modeling results that no CHANGE amendment to the AOR and corrective action plan is needed.

{Appropriate frequency of determining Ao R might not be "fixed." Owner or operator might need to reevaluate AoR fre quently at first, particularly with deep brine formations about which there is little hist ory, and then at expanding intervals as more information is known.}

Response: EPA agrees that site-specific factors should be considered in the reevaluation schedule, and notes that the AoR and corrective action plan must specify the site-specific monitoring and operational conditions that warrant reevaluation, as specified in §146.84(b)(2)(ii). In addition, the Director has discretion to require more frequent AoR reevaluation if he or she has reason to believe, based on sitespecific information, that a five-y ear reevaluation schedule is not sufficiently protective of USDWs. However, EPA believes that setting a minimum reevaluation frequency is appropriate. In the final rule, the Agency changed the minimum frequency for the AoR reevaluation at §146.84(e) from 10 years to at least every 5 years in the final GS rule. EPA believes that this revised frequency addresses commenters' concerns about the inherent uncertainties in modeling CO2 movement, the emerging nature of GS technology, risk-based targeting of monitoring activiti es, and the unique nature of CO2 GS.

Other EPA Comment Codes and Descriptions: 3800 2.3 Proposed Injection Well Construction Requirements ( 40 CFR 146.86) Comment: §146.86 Injection well construction requireme nts. (a) General. The owner or operator must ensure that all Class VI wells are constructed and completed to: Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24780

Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24781(1) Prevent the ENDANGERMENT OF USDWs move ment of fluids into or between USDWs or into any unauthorized zones ; (2) Permit the use of appropriate test ing devices and workover tools; and (3) Permit continuous monitoring of the annulus space between the injection tubing and long string casing.

Response: EPA disagrees with the suggested edit. EPA believes that protection of USDWs from endangerment and prevention of fluid movement between formations is paramount, and believes that the language as proposed regarding preventing fluid movement is more specific and protective. Appropriately designed and constructed wells are necessary to prevent endangerment to USDWs and maintain integrity of the well th roughout the lifetime of a GS project. This is the foundation of the requirements for construction a nd pre-operational testing of Cl ass VI wells at §§146.86 and 146.87.

Other EPA Comment Codes and Descriptions: 3860 2.3.3 Well component degradation Comment: (b) Casing and Cementing of Class VI Wells.

(1) Casing and cement or othe r materials used in the construction of each Class VI well must have sufficient structur al strength and be designed for the OPERATING life of the WELL geologic sequestration project . All well materials must be compatible with flui ds with which the materials may be expected to come into contact and meet or exceed standards developed for such materials by the API, ASTM International, or comparable standards acceptable to the Director. The casing and cementing pr ogram must be designed to prevent the movement of fluids into or between USDWs. In order to allow the Director to determine and specify casing and ce menting requirements, the owner or operator must provide the following information:

{The threat to the integrity of the casing and cement and other materials is greatest during injection, and quickly de creases as the pressure dissipates after cessation of injection. }

Response: EPA disagrees that the casing, cement or other materials should only be designed for the
p eriod of the injection process, ra ther than the life of the seques tration project. GS projects are anticipated to have long life spans in comparison to other types of deep injection wells. Not only must Class VI wells be able to function sa fely and properly over the lifespan of the GS project, but they must b e constructed such that USDWs remain protecte d after well plugging. The requirements at §146.86 will ensure that the well can maintain integrity thr oughout the proposed life span of the project, including after the injection well is plugged and through post-injection site care period and beyond. While the risk
p rofile of a GS site will decrease following cessation of injection, EPA believes that Class VI wells must be designed to protect USDWs from endangerment for the life of the project. Furthermore, rigorous casing and cementing help ensure th at the Class VI well will not se rve as a conduit for movement of fluids associated with future injection operations.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24782

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24783(seeking comment) Comment: (i) Depth to the injection zone; (ii) Injection pressure, external pressure , internal pressure and axial loading; (iii) Hole size; (iv) Size and grade of all casing strings (E.G., wall thickness, external diameter, nominal weight, length, jo int specification and construction material); (v) Corrosiveness of the carbon dioxi de stream, and formation fluids; (vi) Down-hole temperat ures AND PRESSURES; (vii) Lithology of injecti on and confining zones; (viii) Type or grade of ceme nt, INCLUDING ADDITIVES; and (ix) Quantity, chemical composition, and temperature of the CO2 stream.

{Redundant - look at appl ication requirements.}

Response: EPA agrees with the suggestion that §146.86(b)(1 )(viii) be revised to also address cement additives. In the final GS rule, the subparagraph read s as follows: "Type or gr ade of cement and cement additives."

EPA clarifies that information on down-hole pressures is required at §146.86(b)(1)(ii).

Other EPA Comment Codes and Descriptions: 3822 2.3.1.1 Depth of surface casing (seeking comment) Comment: (2) Surface casing must extend through the ba se of the lowermost USDW ABOVE THE INJECTION ZONE and be cemented to the surface.

Response: EPA disagrees with the suggested edit. The final GS rule at § 146.86(b)(2) requires that surface casing extend through the base of the lowerm ost USDW and be cemented to the surface through the use of a single string or multip le strings of casing and cement.

EPA stresses that protection of USDWs from endangerment, regardless of their depth or the number of USDWs in an area, is the primary mission and ma ndate of the UIC program and the purpose of all requirements for injection wells. A ny injection activity must be demonstrated to not endanger USDWs, regardless of their depth, and if such non-endangerment cannot be shown, the activity will not be allowed under UIC requirements or the SDWA.

EPA recognizes concerns re garding construction of Class VI well s where the lowermost USDW is very deep. To further address comments on deep inje ction wells, the final GS rule at §146.95 includes requirements for owners or operators that seek a waiv er of the injection depth requirements. Owners or operators of Class VI wells operating under inject ion depth waivers must comply with additional construction requirements to ensure that wells used to inject above or between USDWs are protective. EPA believes that, given the possibi lity for Class VI wells to operate under injection depth waivers, the requirement that surface casing must extend through th e base of the lowermost USDW is important for USDW protection. Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24784

Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24785Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: (3) At least one long string casing, using a sufficient number of centralizers, must extend to the injection zone and must be cemented by circulating cement to the surface in one or more stages.

{Circulation of cement unnecessa ry and more stringent that requirement for Class I hazardous waste wells. RRC suggests that it may not be tec hnically feasible to cement the full column of one long string casing because the formations you likely want to inject into are low-pr essure, and typically won't hold a full column of cement, making circulation impossible. RRC suggests a certain footage of cement, such as 600 ft, and require a bond log to verify it. }

Response: EPA believes that the construction requirement s at §146.86 offer flexibility to the owner or operator to propose well construction procedures that are appropriate to the s ite-specific conditions of the project. Section 146.86(b)(3) requires that the long-string casi ng extend to the injection zone and be cemented by circulating cement to th e surface in one or more stages . It does not, however, specify how cementing would be accomplished, and gives flexibilit y to the owner or opera tor to propose alternate methods to provide a sufficient amount of cement to meet the standa rd that USDWs are protected from endangerment, subject to the approva l of the Director. EPA notes that there are many potential ways to meet the requirement, such as the use of staged cementing.

EPA believes that current cementing technology can a ddress deep well cement columns or low-pressure bottom-of-hole formations. The oil and gas industry has experience dril ling and cementing wells in very deep formations and in form ations with low pressures. Less dense, lighter weight ceme nt slurries that include nitrogen foam or lightwei ght microspheres (Sabins 2002; Kula kofsky et al. 2005) are used to
p revent breakdown of the low pressure formation and loss of circulat ion. Another way to approach low formation pressure conditions is with reverse cementing (pumping the cement into the annulus and returning it through the casing). This method uses grav ity to place the cement a nd bypass lost circulation zones. Reverse cementing can be combined with other methods such as foam cement. Ten successful reverse-cemented wells have been completed in a variety of onshore/offshore environments (Chase 2008).

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements (seeking comment) Comment: (5) Cement and cement additives must be compatible with the CO2 stream and formation fluids and of su fficient quality and quantity to maintain integrity over the design life of the W ELL geologic sequestration project . The integrity and location of the cement shal l be verified using technology capable of evaluating cement quality radially and identifying the location of channels to ensure that USDW s are not endangered.

{ See comment above. } Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24786Response: EPA disagrees that the casing, cement or other materials should only be designed for the
p eriod of the injection process, ra ther than the life of the seques tration project. GS projects are anticipated to have long life spans in comparison to other types of deep injection wells. Not only must Class VI wells be able to function sa fely and properly over the lifespan of the GS project, but they must b e constructed such that USDWs remain protecte d after well plugging. The requirements at §146.86 will ensure that the well can maintain integrity thr oughout the proposed life span of the project, including after the injection well is plugged and through post-injection site care period and beyond. While the risk
p rofile of a GS site will decrease following cessation of injection, EPA believes that Class VI wells must be designed to protect USDWs from endangerment for the life of the project. Furthermore, rigorous casing and cementing help ensure th at the Class VI well will not se rve as a conduit for movement of fluids associated with future injection operations.

Other EPA Comment Codes and Descriptions: 3826 2.3.1.3 Packer requirements (seeking comment) Comment: (i) Depth of setting; (ii) Characteristics of the CO2 stream (chemical content, corrosiveness, temperature, and density); (iii) Injection pressure; (iv) Annular pressure; (v) Injection rate (intermittent or continuous) and vol ume of the CO2 stream; (vi) Size of casing; and (vii) Tubing tensile, burst, and collapse strengths.

{Repetitive - See applic ation requirements}

Response: EPA acknowledges that some of the info rmation required under §146.86(c)(3) is also required under §146.82(a)(7) as part of the proposed operating requirements. However, EPA notes that the Director needs to consider all of the data required under §146.86(c) in order to properly determine the tubing and packer specifications, and believes this information should be provided together.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: (c) The owner or operator must record the fluid temperature, pH, conductivity, reservoir pressure and the static fl uid level of the injection zone(s).

Response: The text at §146.87(d) as writte n requires data on the injecti on zone and confining zone or zones. This is to ensure that, if the Di rector requires characterization of additional containment/confining zones (§146.83(b)), appropriate data are collected.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: (d) At a minimum, the owner or operato r must determine or calculate the Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24787

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24788

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24789following information concerning th e injection and confining zone(s) :

Response: The text at §146.87(d) as writte n requires data on the injecti on zone and confining zone or zones. This is to ensure that, if the Di rector requires characterization of additional containment/confining zones (§146.83(b)), appropriate data are collected.

Other EPA Comment Codes and Descriptions: 4110 2.4.1.1 Injection pressure limitations Comment: (a) Except during stimulation, the owner or operator must ensure that injection
p ressure does not exceed 90% of the fracture pressure of the injection zone so as to assure that the injection does not initiate new fractures or propagate existing fractures in the injection zone . In no case may injection pressure initiate fractures in the confining zone(s) or cause the movement of injection or formation fluids that endangers a USDW.

Response: EPA disagrees with the suggested edit. The rule affords the Director discretion to require more than one confining zone, as specified at §146.83(a)(2). Where more than one confining zone is required, EPA believes that each confining zone provides a layer of protection for USDWs and should remain intact. See the preamble discussion geologic siting requireme nts for additional information.

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: (e) The owner or operator must install a nd use continuous recording devices to monitor: The injection pr essure; the rate, volume, and temperature of the carbon dioxide stream; and th e pressure on the annulu s between the tubing and the long string casing and annul us fluid volume; and must install and use alarms and automatic down

- hole shut-off systems, designed to alert the operator and shut-in the well when operating parameters such as annulus pressure, injection rate or other parameters approved by the Director diverge beyond permitted ranges and/or gradients specified in the permit;

{RRC suggests that the rule not require automatic shutdown. Experience in the field has been that ESDs are notorious for high maintenance, and continuous monitoring will sufficiently alert the operator of a need to shut down operations. In addition, such a requirement is more stringent than that required for Class I hazardous waste wells.}

Response: After evaluating the risks and benefits of down-hole shut-off systems and considering additional research, EPA will not require automa tic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells install automatic surface shut-off devices. The rule afford s Director's discretion to mandate automatic downhole shut-off devices in onshore situations that may warrant their use. The rule requires, at §146.88(e)(3) that owners or operators of offs hore wells within State territorial waters install automatic down-hole shut-off systems. Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24790

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24791EPA recognizes that down-hole sh ut-off devices may make well maintenance and operation more challenging. However, the buoyant natu re of CO2 and the elevated injection pressures associated with GS increase the likelihood of an uncontrolled flow of CO2 out of the well, which may endanger USDWs. If CO2 does begin to flow back up an injection well, it will rapidl y cool and expand as it moves toward the surface and can result in a str eam of solid CO2 which can cause damage to the wellhead and other well instrument ation; such damage has been documented in CO2 ER wells (Skinner, 2003; Duncan et al., 2008). Additionally, the Agency believes that offshore Class VI wells present unique construction and operational conditions, includi ng isolation from shorelines and the need to construct wells through the water column and the subsurface, which may delay response time in the event of well difficulties. Automatic shut-off devices can help prevent further well complications, and EPA believes affording Director's discretion to re quire down-hole devices where necessary ensures that
p roper precautions are taken to prevent subsurface fl uid movement and ensure protection of USDWs, human health, and the environment.

EPA believes that requiring automatic surface shut -off devices instead of down-hole devices provides more flexibility to owners or operators when performing required mechanical integrity tests. Additionally, this requirement addresses concerns a bout risks associated with routine well workovers that may be complicated by the presence of dow n-hole devices while still maintaining USDW
p rotection.

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: (f) If a down

- hole automatic shutdown is triggered or a loss of mechanical integrity is discovered, the owner or operator must imme diately investigate and identify as expeditiously as po ssible the cause of the shutoff . If, upon such investigation, the well appears to be lacking mechanical integrity, or if monitoring required under paragraph (e) of th is section otherwise indicates that the well may be lacking me chanical integrity, the owner or operator must:

Response: As described above, after evaluating the risks and benefits of down-hole shut-off systems and considering additional researc h, EPA will not require automati c down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2 ), affords Director's discretion to mandate automatic down-hole shut-off device s in onshore situations that may warrant their use. However, the Agency believes that offshore Class VI wells pr esent unique construction and operational conditions, including isolation from shorelines and the need to construct wells through the water column and the subsurface, which may delay response time in the even t of well difficulties. The rule requires, at §146.88 (e)(3), that owners or operators of offshore wells within State territ orial waters install automatic downhole shut-off systems.

Other EPA Comment Codes and Descriptions: 4520 2.5.1 Continuous internal mechanical integrity monitoring (seeking comment); 4720 2.7.2 Oper ational recordkeeping and reporting Comment: (b) To evaluate the absence of signifi cant leaks under pa ragraph (a)(1) of this section, owners or ope rators must, following an initial annulus pressure test, continuousl y monitor in j ection pressure, rate, in j ected volumes, and Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24792

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24793p ressure on the annulus between tubing a nd long stem casing and annulus fluid volume as specifi ed in §146.88(e);

{Redundant language.}

Response: The final rule retains this text to provide clarity about requirements for demonstrating internal mechanical integrity and to specify the necessary monitoring. EPA be lieves that continuous
p ressure monitoring to demonstrate internal mechani cal integrity of Class VI wells (146.89(b)), instead of periodic testing (which is require d for most other types of deep injection wells) is important given the
p otential corrosive impact of CO2 and impurities on well materials, the potential geomechanical impacts to well integrity due to CO2 phase changes, and the temperature and pressure effects associated with injecting supercritical CO2.

For additional information, please see the discu ssion of MITs in the final rule preamble.

Other EPA Comment Codes and Descriptions: 4660 2.6.6 Geochemical monitoring Comment: (d) Periodic monitoring of the ground water quality and geochemical changes above the confining zone(s) that may be a result of carbon dioxide movement through the confining zone or a dditional identified zones:

Response: Regarding monitoring locations, section §146.90(d) requires periodic monitoring of the ground water quality and geochemica l changes above the confining zone (s). EPA clarifies that this monitoring requirement does not include the confining layer itself. Monitoring ab ove the confining layer will provide an indication of upward movement of CO2 that might endanger a USDW. The exact number of formations to be tested must, however , be based on site-specific characteristics and vulnerabilities and described in the Director-approved testing and monitoring plan.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: (e) A demonstration of external mechan ical integrity pursuant to §146.89(c) at least once per year throughout the dur ation of INJECTION the geologic sequestration project;

{Demonstration of external mechanical integrity should not be necessary after cessation of injection and (r elatively immediate) dissipation of pressure near the wellbore resultin g from injection.}

Response: In the final rule, EPA has revised the text at §144.90(e) to specify that owners or operators must demonstrate internal MI at least onc e per year until the well is plugged.

Other EPA Comment Codes and Descriptions: 4650 2.6.5 CO2 plume and pressure front tracking (seekin g comment) Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24794

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24795

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24796Comment: (g) Testing and monitoring to track the extent of the carbon dioxide plume and the position of the pressure front by ei ther monitoring for pressure changes in the first formation overl ying the confining zone or using indirect, geophysical techniques (e.g., se ismic, electrical, gravit y, or electromagnetic surveys and/or down-hole CO2 detection tools);

{If there are changes in the first formation overlying the confining zone, the carbon dioxide stream has not been confined.}

Response: The final rule, at §146.90(g), requires owners or operators to perform monitoring to track the extent of the CO2 plume and pressure front. The owner or operator must use direct methods to monitor for pressure changes in the injection zone. Indirect methods (e.g., seismic, electrical, gravity, or electromagnetic surveys and/or down-hole CO2 dete ction tools) are required unless the Director determines, based on site-specific geology th at such methods are not appropriate

EPA believes that pressure monitoring in the inject ion zone is necessary to track the development and movement of the pressure front and CO2 plume. When combined w ith information on temperature,
p ressure data provide an indication of the phase (e.g., gas, supercritical) and distribution of the injected CO2 (73 FR 43515). Monitoring can also identify ne eded remedial actions, provide inputs for AoR reevaluation modeling, evalua te predictions of plume movement, a nd target additional geochemical and surface monitoring needs.

EPA adds that owners or operato rs may consider (or the Director may require) performing additional
p ressure monitoring in wells that ar e above the confining zone (e.g., in the same wells used to perform ground water quality monitoring required at §146.90(d)) to provide additional verification that no
p ressure changes are occurring above the confining zone due to CO2 leakage. The final rule, at §146.90 (d), also requires geochemical moni toring above the confining zone.

Other EPA Comment Codes and Descriptions: 4670 2.6.7 Surface air monitoring and/or soil gas monitoring (seeking comment) Comment: (h) At the Director's discretion, surface air monitoring and/or soil gas monitoring to detect movement of carbon dioxide that could endanger a USDW. (1) The testing and monitoring plan must be based on potential vulnerabilities within the area of review; (2) The moni toring frequency and spatial distribution of surface air monitoring and/or soil gas monitoring must reflect baseline data and the monitoring plan must include how the proposed monitoring will yield useful information on the area of revi ew delineation and/or compliance with standards under 40 CFR 144.12;

{Any requirement for surface air monitoring and/or soil gas monitoring is not warranted. If the purpose is to detect "m ovement of carbon dioxide that could endanger a USDW, it w ould be too late if carbon dioxide were detected in the air or soil. In addition, levels of ambient carbon dioxide are too variable for this to be useful. RRC suggests elimin ating any potential requirement for surface air or soil gas monitoring, becau se formation monitoring should catch whatever condition might reasonably be exp ected to be caught by surface or soil gas monitoring. } Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24797Response: EPA acknowledges that air and soil gas monitoring to ensure USDW protection is not necessary at all GS sites and beli eves that the decision to use surface monitoring and the selection of monitoring methods for the purpose of USDW protecti on will be site-specific. In the final rule, at §146.90(h), the decision to require such monitoring as an additional measure to ensure USDW
p rotection rests with the Di rector as a means of identifying leaks that may pose a risk to USDWs and informing emergency notification of a Class VI owner or operator and UIC Director in the event of a USDW endangerment, pursuant to requirement s at §146.91(c).

EPA clarifies that subsurface geochemical and pressure monitoring in the subsurface formations are the first line of monitoring that w ould allow detection of potential endangerment to USDWs from GS activities (this is required at all GS sites, as described at §146.90(d)). The Agency also believes that surface air and soil gas monitoring, when coupled wi th subsurface monitoring, may be appropriate at some GS projects to ensure USDW protection. EPA acknowledges that surface air and soil gas monitoring may not be suitable in all settings as a method to ensure USDW protection. However, EPA does not believe that this should entirely preclude their use. The decision to use surface monitoring and the selection of monitori ng methods will be site-specific (e.g., may be influenced by geology, injection depth, and operational conditions) and must be based on potential risks to USDWs within the AoR.

Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities Comment: (1) The owner or operator must submit the post

- injection site care and site closure plan as a part of the permit application to be approved by the Director.

{Redundant - See 146.82(w).}

Response: EPA clarifies that the reference to the post-inj ection site care and site closure plan, in the final rule at §146.82(a)(17), requires th at the plan be included in the attachments to the Class VI permit application. The details of the plan contents are included in §146.93, along with other requirements related to post-injection site care and site closure.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: (i) The pressure differenti al between pre-injection a nd predicted post-injection
p ressures in the injection zone; (ii) The predicted position of the carbon dioxide plume and associated pressure front at site closure as demonstrated in the AOR evaluation require d under §146.84(b); (iii) A de scription of postinjection monitoring location, methods, and proposed frequency; and (iv) A
p roposed schedule for submitting post-injection site care monitoring results to the Director.

{This should be referenced in 146.82(w).}

Response: EPA clarifies that the reference to the post-inj ection site care and site closure plan, in the final rule at §146.82(a)(17), is to re quire that the plan be included in the attachments to the Class VI
p ermit application. The details of the plan contents are included in §146.93 and are enforceable permit Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24798

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24799conditions, along with other requirements related to post-injection site ca re and site closure.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: (3) Upon cessation of injection, THE OWNER OR OPERATOR MUST either submit an amended post-injection site care and site closure plan or demonstrate to the Director through monitoring da ta and modeling results that no amendment to the
p lan is needed.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5200 2.8.2 Post injecti on site care (seeking comment) (40 CFR 146.93) Comment: (4) THE OWNER OR OPERATOR MAY May modify and resubmit the post-injection site care and site closure plan for the Director's approval within 30 days of such change.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities; 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: (b) THE OWNER OR OPERATOR MUST Must monitor the site following the cessation of injection to show the position of th e carbon dioxide plume and pressure front and demonstrate that USDWs are not being endangered.

(1) THE OWNER OR OPERATOR MUST Must continue to conduct monitoring as specified in the Director-approved post-in jection site care and site closure
p lan for THE PERIOD OF TIME at least 50 years following the cessation of injection . At the Director's disc retion, the monitoring will continue until THE DIRECTOR DETERMINES THAT the geol ogic sequestration project no longer poses an endangerment to USDWs.

Response: EPA disagrees with the suggested edits. However, EPA agrees with commenters that there will be circumstances where it ca n be demonstrated in less than 50 years that the plume and pressure front no longer pose a risk of endangerment to USDWs. For this reason, the final GS rule offers owners or operators flexibility regardi ng the duration of the PISC timefr ame by: (1) allowing the Director discretion to shorten or lengthen th e PISC timeframe during the PISC period based on site-specific data,
p ursuant to requirements at §146.93(b); or (2) affordin g the Director discretion to allow a Class VI well Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24800

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24801

Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24802owner or operator to demonstrate, based on substantial data during the permitting process, that an alternative PISC timefram e may be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts.

Other EPA Comment Codes and Descriptions: 5280 2.8.2.4 USDW non-endangerment demonstrations Comment: (3) Prior to authorization for site clos ure, must submit to the Director a demonstration, based on monitoring and ot her site-specific data, that the carbon dioxide plume and pressure front have stabilized and that no additional monitoring is needed to assure that the GS project does not pose an endangerment to USDWs.

{The carbon dioxide plume will continue to move with other formation fluids - they are never static. The real test shoul d be whether or not the pressure has dissipated and the pressure front stabil ized to the point that there is no threat of endangering USDWs.}

Response: EPA did not make the suggested change. EPA agrees that a complete cessation of plume movement may not occur at some sites for long ti me periods due to density differences, natural formation flow gradients and diffusion. EPA clarifies that a complete cessation of plume movement is not required, only a demonstration that the plum e and pressure front no longer pose a risk of endangerment to USDWs.

EPA acknowledges that many site-speci fic factors will influence the determination of when the CO2
p lume and pressure front no longer pos e a risk of endangerment to USDW s. It is for this reason that EPA believes that individual UIC Directors, in consultation with operators, will be in the best position to determine whether additional post-inje ction site care is needed. EPA e xpects this decision to be made based on relevant site data and in consultati on with all potentially impacted parties.

EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and m onitoring wells; perform post-inj ection monitoring; demonstrate non endangerment; and perform site closure activities. The guida nce will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm. Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24803

Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24804Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment); 5260 2.8.2.3 Adjusting the post-injection timeframe (seeking comment) Comment: (4) If such a demonstration cannot be made after the 50

- year period, must submit to the Director a plan to continue post

- injection site care.

{See comment above.}

Response: As described above, the post-inje ction site care timeframe may be reduced by the Director if the owner or operator can de monstrate that the remaining pressure front and plume no longer pose a risk of endangerment to USDWs. The non-endangerment findi ng is left to the discretion of the Director, based on site-specific information such as plum e movement, pressure decay, and the location of
p otential leakage pathways. As suggested by the co mmenter, a complete cessation of plume movement is not required, only a demonstration that the pl ume and pressure front no longer pose a risk of endangerment to USDWs, as specified in §146.93(b)(2-4 ). EPA retains this provision in the final GS regulation GS rule also offers owne rs or operators flexibility regarding the duration of the PISC timeframe by affording the Director discretion to allow a Class VI well owner or operator to demonstrate, based on substantial data during the permitting process, that an alternative PISC timefram e may be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c). EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care Comment: (c) Notice of intent for site closure. Must notify the Director at least 120 days before site closure. At this time, if any changes have been made to the original post-injection site care and site closure pla n, THE OWNER OR OPERATOR must also provide the revised plan. At th e discretion of the Di rector, a shorter notice period may be allowed.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the final rule and discussion of post-injection site ca re in the preamble to the rule for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: (d) After the Director has authorized site closure, THE OWNER OR OPERATOR must
p lug all monitoring wells in a manner which will not allow movement of injection or formation fluids that endan g ers a USDW. Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24805

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24806Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: (e) Once the Director has authorized site closure, THE OWNER OR OPERATOR must submit a site closure report within 90 days that must thereafter be retained at a location designated by the Direct or. The report must include:

(1) Documentation of appropriate inje ction and monitoring well plugging as specified in §146.92 and paragraph (c) of th is section. Must provide a copy of a survey plat which has been submitted to the local zoning au thority designated by the Director, which indicates the locati on of the injection well relative to
p ermanently surveyed benchmarks. Must also submit a copy of the plat to the regional administrator of the appropriate EPA Regional Office ;

{Why is this necessary? The EPA regional office will have access to all records at the State. }

Response: The GS regulation at §146.93(g) requires the owne r or operator to record a notation on the deed to the facility prope rty or other similar document examined during a title search that the land has been used to sequester CO2 at the time of site closure.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: (f) THE OWNER OR OPERATOR MUSTMust record a notation on the deed to the facility property or any other document th at is normally examined during title search that will in perpetuity provide any potential purchaser of the property the following information:

(1) The fact that land has been used to sequester carbon dioxide; (2) The name of the State agency, local authority, and/or tribe with which the survey plat was filed, as well as th e address of the Regional EPA Office to which it was submitted ; and (3) The volume of fluid injected, the injection

zone or zones into which it was injected, and the period over which injection occurred.

Response: The GS regulation at §146.93(g) requires the owner or operator to record a notation that the land has been used to sequester CO2 on the deed to th e facility property at the time of site closure. Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24807

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24808

Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24809Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: (g) Must retain for three years following site closure, records collected during the post-injection site care period. THE OWNER OR OPERATOR MUST Must deliver the records to the Director at the conclusion of the retention period, and the records must thereafter be retained at a location designated by the Director for that purpose.

Response: EPA disagrees that the owner or operator should not be responsible for record retention such as site closure reports. EPA believes that the require ments that the owner or operator retain for ten years following site closure, records collected during the post-injecti on site care period at §146.93(f) and §146.93(h) are appropriate for the post-injection and site closure period to ensure that data are available to support non-endangerment de monstrations and to address any con cerns that may arise following site closure. This data will also suppor t EPA's review of project data as part of the adaptive rulemaking approach.

Other EPA Comment Codes and Descriptions: 5000 2.8 Proposed Well Plugging and Post-Injection Site Care Requirements Comment: §146.94 Emergency and remedial response.

(a) As part of the permit application, TH E OWNER OR OPERATOR must provide the Director with an emergency and remedial response plan that describes actions to be taken to address movement of the inject ion or formation fluids that may cause an endangerment to a USDW during cons truction, operation, closure and postclosure periods.

{Redundant - See 146.82(X)}

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities; 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: (2) If the owner or operator can demo nstrate to the satisfaction of the Director before 50 years, based on monitoring and other site

- specific data, that the GS project no longer poses an enda ngerment to USDWs, the Director may approve an amendment to the post

- injection site care and site closure plan to reduce the frequency of monitoring or may authorize site closure before the end of the 50

- year period.

{The period of time an owner or operato r is required to conduct post-closure care monitoring should be based on the ab ility of the pressure to cause endangerment of USDWs. A 50-year post-closure care monitoring period is unprecedented and implies that CO2 presents a g reater risk than it does. RRC Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24810

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24974suggests that EPA strike the phrase "for at least 50 years" and make the time for continued monitoring be base d on site specific data. }

Response: EPA disagrees that a post-injection site care timeframe of 50 years is excessive for most Class VI wells. EPA proposed a defa ult post-injection site care timefr ame of 50 years based on a review of research studies, industry reports , and existing environmen tal programs. This analysis was included in an EPA-prepared background document that is available in the fede ral docket, titled "Computational Modeling of Underground In jection of Carbon Dioxide for Dete rmination of Area-of-Review and Potential Risk to Underground Sources of Drinking Water." EPA assessed various default timeframes based on additional review of re search studies and evaluation of public comments. While numerous commenters suggested that EPA shorten the monito ring timeframe, none of the commenters provided sufficient data or other evidence to warrant a ch ange in the proposed time frame. While the 10- or 30- year timeframe suggested by some of these commenters may be within the timeframe suggested in some studies, EPA believes that the potential risks of e ndangering USDWs will likely not decline within these timeframes and available data, including data submitted by commenters, do not support a different default timeframe. However, EPA recognizes that alternative time frames may be appropriate under limited, specific circ umstances, which is why EPA is providing the Director discretion to approve an alternative post-injection site care timeframe as long as the owner or operator can meet the requirements
p rovided at §146.93(c).

EPA acknowledges there will be circum stances where it can be demonstrated in less than 50 years that the plume and pressure front no longer pose a risk of endangerment to USDWs. For this reason, the GS rule offers owners or operators flexibility regardi ng the duration of the PISC timeframe by: (1) allowing the Director discretion to shorten or lengthen the PISC timeframe during the post-injection period based on site-specific data, pursuant to requirements at §146.93(b); or (2) affo rding the Director discretion to allow a Class VI well owner or operator to demonstrate, during the permitting process based on substantial data, that an alternative PISC timefram e may be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe for
p ost-injection site care will be necessary in most cases. The default 50 year post-injection site care timeframe represents a r easonable and protective monitoring peri od based on a review of research studies, industry reports, and exis ting environmental programs, and evaluation of public comments.

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mon itoring and USDW impacts.

Comment: Technical Fix to the GS Rule to Properly Include Indian Tribes

Finally, in reading the GS rule, the NT AA found that the EPA inadvertently omitted the phrase "tribal authorities" under section 146.94(c)(2). To rectify this omission from the se ction, the NTAA recommends the following language: Commenter Name: Sam Kitto Letter ID: 0126 Commenter Or g anization: National Tribal Air Association Comment ID: 23051"Documentation of appropriate notificat ion and information to such State, Tribal, and local authorities as have authority over drilling activities to enable such State, Tribal and local aut horities to impose appropriate conditions on subsequent drilling activities that may penetrate the injection and confining zone(s)."

Response: EPA presumes the commen ter is referring to the final ru le requirement at §146.93(f)(2). EPA clarifies that the text reads as follows, "Documen tation of appropriate notifi cation and information to such State, local and Tribal authorities as have authority over drilling activities to enable such State, local, and Tribal authorities to impose appropriate conditions on subse quent drilling activities that may
p enetrate the injection and confining zone(s)."

For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: Fluid Movement

The UIC regulations have, from the beginning, included two standards of
p rohibition of fluid movement that may be appropriate for geological sequestration of carbon dioxi de. The fluid movement re quirement for Class I injection wells states:

The well must be constructed, operated, maintained, and plugged such that injection activities will not ca use movement of any contaminant into a USDW

The fluid movement requirement for Class V injection wells states:

N o owner or operator shall construct, operate, maintain, convert, plug, abandon, or conduct any other injection activity in a manner that allows the movement of fluid containing any contaminant into underground sources of drinking water, if the pres ence of that contaminant may cause a violation of any primary drinking water regulation under 40 CFR part 142 or may otherwise adversely aff ect the health of persons. The applicant for a permit shall have the burden of showing that the requirements of this paragraph are met.

The NGWA recommendation for carbon seque stration well permitting includes an experimental phase for eac h location that will be used for geological sequestration of carbon dioxide. Wells c onstructed during th e experimental
p hase at each location will have extens ive testing requirements and exploratory objectives that will not be needed duri ng the operational phase. It will not be necessary or practical to a pply the same standard of fluid movement to both the experimental phase and the operati onal phase of carbon sequestration.

The NGWA recommendations also include earl y warnin g monitorin g to detect Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22553movement of fluids containi ng carbon dioxide or contaminants before the fluids reach a USDW. The advantage of early warning monitoring is in the ability to detect fluid movement before a dri nking water supply is impacted. The identification of a ge ological unit that can serve as secondary cont ainment for the injected fluid is addressed in th e NGWA recommendations for geologic characterization. It is recommended that early warning monitoring be included in the requirements for operation of Cla ss V experimental carbon sequestration wells, as well as Class VI opera tional carbon sequestration wells. The requirement for early warning monitoring should incl ude authorization for action by the regulatory agency when fluid moveme nt is detected by the early warning monitoring system.

Class V Experimental Carbon Sequestration Well: During the expe rimental phase of injection, while the well is permitted as a Class V well, the following fluid movement criteri on should apply:

N o owner or operator shall construct, operate, maintain, convert, plug, abandon, or conduct any other injection activity in a manner that allows the movement of fluid containing carbon dioxide or any contaminant into underground sources of drinking water, if the presence of carbon dioxide or that contaminant may cause a viol ation of any primary drinking water regulation under 40 CFR part 142 or may otherwise adversely affect the health of persons. The applicant for a permit shall have the burden of showing that the requirements of this paragraph are met.

Class VI Operational Carbon Sequestration Well: During the operational phase of injection, while the well is permitted as a Class VI well, the following fluid movement criteri on should apply:

N o owner or operator shall construct, operate, maintain, convert, plug, abandon, or conduct any other injection activity in a manner that allows the movement of fluid containing carbon dioxide or any contaminant into underground sources of drinking water, if the presence of carbon dioxide or that contaminant may cause a viol ation of any primary drinking water regulation under 40 CFR part 142 or may otherwise adversely affect the health of persons. Additionally, no ow ner or operator shall construct, operate, maintain, convert, plug, abandon, or conduct any other injection activity in a manner that allows the movement of carbon dioxide in gaseous phase to land su rface, nor limit the extraction of drinking water from a underground sour ces of drinking water by reduction of porosity or changes in pH or water quality due to geochemical reactions, or by causing a buildup of ga s in the underground sources of drinking water. The applicant for a permit shall have the burden of showing that the requirements of this paragraph are met.

If any water quality monitoring of an underground source of drinking water indicates the movement of any contaminant into the underground source of drinking water, or a violat ion of any part of the preceding
p aragraph, except as authorized unde r part 146, the Director shall
p ublish a notice in newspape rs of general circulation in whose service area the fluid movement was detect ed. If a meritorious request issubmitted by the public, the Director shall prescribe such additional requirements for construction, corr ective action, operation, monitoring, or reporting (including closure of the injection well) as are necessary to prevent such movement.

Response: EPA does not agree that each GS si te must first be permitted as an experimental Class V well before being authorized to operate a full-scale Class VI well. Follow ing the promulgation of the final rule, EPA will allow the use of Class V experi mental technology permits only for experimental
p urposes; i.e., to test new, unproven technologies. EP A does not consider it appropriate to permit CO2 injection wells that are testing th e injectivity or appropr iateness of an individua l formation (e.g., as a
p relude to a commercial-scale ope ration) as Class V experimental technology wells. Such wells should be permitted as Class VI wells.

The final rule at §146.90(g) requires owners or operators to track the extent of the CO2 plume and
p ressure front. The owner or operator must use direct methods to monitor for pressure changes in the injection zone. Indirect methods (e.g., seismic, electrical, gravity, or electromagnetic surveys and/or down-hole CO2 detection tools) ar e required unless the Director de termines, based on site-specific geology, that such methods are not appropriate.

EPA believes that pressure monitoring in the inject ion zone is necessary to track the development and movement of the pressure front and CO2 plume. Monitoring can also id entify needed remedial actions,
p rovide inputs for AoR reevaluati on modeling, evaluate predictions of plume movement, and target additional geochemical and surface m onitoring needs. Knowledge of the location of the CO2 plume and the associated pressure front will also assure the public that GS projects are proceeding according to
p lan, provide sufficient information to the owner or operator and Director, or allow for appropriate actions to address a ny indication that USDWs may be endangered.

In addition to monitoring to track the movement of the CO2 plume and pressure front, EPA believes that monitoring above the confining layer is an important part of a rigorou s monitoring program and can help detect potential breaches of the confining zone. Such monitoring can provide an early warning that the
p lume or other substances may be approaching a USDW. The final rule, at §146.90(d), requires periodic monitoring of the ground water quality and geoche mical changes above the confining zone(s). Monitoring in additional formations, e.g., the injection zone, may also be necessary, and if the Director b elieves such monitoring is warranted he/she has the authority to require that it be included in the testing and monitoring plan. EPA adds that the baseline geochemical data required at §146.82(a)(6) will help owners or operators interpret the results of this monitoring.

EPA acknowledges that there are poten tial risks associated with GS, including the potential for leakage of CO2 or other substances into USDWs. However, the purpose of the UIC regulations including the Class VI requirement s is to protect USDWs from endangerment. In order to protect USDWs from endangerment §144.12 prohibits the movement of fluid into USDWs. Consistent with §144.12, EPA is finalizing the Class VI requirement s in order to ensure that USDWs are protected by minimizing and mitigating potential/identified risks through proper site characteri zation, well construction, operation, monitoring, post-injection site ca re, and site closure. The GS rule accomplishes this through requirements tailored to address the unique nature of GS, including the large volumes of CO2 injected, its buoyancy and potential corrosivity in the presen ce of water, and impurities in the CO2 stream. Furthermore, if any water quality monitoring of a USDW indicates the moveme nt of any contaminant into the underground source of drinki ng water, except as authorized under part §146, the Director shall
p rescribe such additional requi rements for construction, correctiv e action, operation, monitoring, or reporting (including closure of the injection well) as are necessary to prevent such movement.Other EPA Comment Codes and Descriptions: 3440 2.2.2.2 Evaluation of wells in the AoR (e.g., types of data to be reviewed) Comment: Proposed Rule: 144.55(a)

Proposed Revision: (a) Coverage. Applican ts for Class I, II, (other than existing), III or VI injection well perm its shall identify the location of all known wells within the injection well's area of review which penetrate the injection zone, or in the case of Cl ass II wells operating over the fracture
p ressure of the injection formation, all know n wells within the area of review
p enetrating formations affected by the in crease in pressure. Applicants for Class VI shall perform mapping with su fficient resolution as to make a comprehensive effort to identify wells that are not in the public record using aerial photography, aerial survey, or other methods acceptable to the director corrective action as specified in §146.84 if needed

Rationale: Concern about the use of th e term known wells. Public records search may not be adequate for older oi l and gas wells, for example. Some language should be added so that A mo re proactive approach is used, e.g.
p hysically walk site or do aerial review.

Response: The final rule leaves §144.55 unchanged from the existing UIC requirements; i.e., Class VI wells are not addressed in this provision. Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Commen t, EPA has made many revisions to the GS Rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Proposed Rule: 146.82

Comment: NGWA raises the question of whether a requirement should be included that all applications for Class VI construction perm its include a certification that the facility was designed by an appropriately qualified professional engineer with an option for an appropria te qualified professi onal geologist to certify the well design (taking into c onsideration confinement, injectivity, etc).

Proposed addition: (1) Class VI - Test/I njection Well Construction and Testing Permit

Proposed addition: (a) The Director shall deny a c onstruction permit if construction of the well itself may enda nger the health of persons or the environment

Proposed addition: (b) For construction perm it approval, reasonable assurance is required that the project will function in compliance with this chapter. The Director shall require an explorator y well for those pro j ects located in an area Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22587

Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22590where available information is lack ing concerning geologic or hydraulic confinement or existing information i ndicates that geologic or hydraulic confinement may be poor or lacking.

Proposed addition: (c ) For a Class VI we ll, issuance of a c onstruction permit does not obligate the Direct or to authorize any opera tion of the well, unless reasonable assurance has been provided that the well can operate in compliance with this chapter.

Proposed addition: (d) Info rmation required in 40 CFR 144.31 (e)(1) through (6)

Proposed addition: (e) A map showing the injection well(s) for which a permit is sought and the applicable area of review . Within the area of review, the map must show the number, or name and loca tion of all injection wells, producing wells, abandoned wells, plugged wells or dry holes, deep stratigraphic boreholes, State or EPA a pproved subsurface cleanup sites, surface bodies of water, springs, mines (surface and subsu rface), quarries, water wells and other
p ertinent surface features including structures intended for human occupancy and roads. The map should also show faults, if known or suspected. Only information of public record is required to be included on this map;

Proposed addition: (f) The ar ea of review based on modeling, using data obtained during logging and testing of the well and the formation as required by
p aragraphs (l), (r ), and (s) of this section;

Proposed addition: (g) Information on th e geologic structure and hydrogeologic
p roperties of the proposed storage site and overlying formations, including

Proposed addition: (1) Maps and cross sections of the area of review;

roposed addition: (2) Location, orientation, and properties of known or suspected faults and fractures that may transect th e confining zone(s) in the area of review and a determination th at they would not interfere with containment;

Proposed addition: (3) Information on seis mic history including the presence and depth of seismic sources and a determin ation that the seismicity would not interfere with containment;

Proposed addition: (4) Data on the dept h, areal extent, thickness, mineralogy,
p orosity, permeability and capillary pressure of the injection and confining zone(s); including geology/facies changes based on field data which may include geologic cores, outcrop data, seismic su rveys, well logs, and names and lithologic descriptions;

Proposed addition: (5) Geomechanical information on fractures, stress, ductility, rock strength, and in situ flui d pressures within the confining zone; and

Proposed addition: (6) Geologic and t opographic maps and cross sections illustrating regional geol ogy, hydrogeology, and the ge ologic structure of thelocal area

Proposed addition: (h) All wells within th e AOR and whose total depth is greater than the depth to the bottom of the lowerm ost USDW should be compiled. However,
p reventive corrective action should be undertaken only for those wells that
p enetrate the injection and confining zone(s)

Rationale: A substantive risk analysis ca n be performed only if all the (known) wells within the AOR and between the inje ction formation and the bottom of the USDW are described.

Proposed addition: (i) Maps and stratigraphic cross sections indicating the general vertical and lateral limits of all USDWs, water wells and springs within the area of review, their positions rela tive to the injection zone(s) and the direction of water movement, where known;

Proposed addition: (j) Baseline geoche mical data on subsurface formations, including all USDWs in the area of review;

Proposed addition: (k) Proposed operating data:

Proposed addition: (1) Average and maximu m daily rate and volume of the carbon dioxide stream;

Proposed addition: (2) Average a nd maximum injection pressure;

Proposed addition: (3) The source of the carbon dioxide stream; and

Proposed addition: (4) An analysis of th e chemical and physical characteristics of the carbon dioxide stream;

Proposed addition: (l) The compatibility of the carbon dioxide stream with fluids in the injection zone and mine rals in both the injection and the confining zone(s), based on the results of the formation testing program, and with the materials used to construct the well;

Proposed addition: (m) Proposed formation testing program to obtain an analysis of the chemical and physical characteristic s of the injection zone and confining

zone;

Proposed addition: (n) Proposed stimulati on program and a determination that stimulation will not interf ere with containment;

Proposed addition: (o) Proposed formation te sting program to obtain an analysis of the chemical, physical and radiologi cal characteristics of and other information on the injection zone.

Proposed addition: (p) Proposed procedure to outline steps necessary to conduct injection operation;

Proposed addition: (q) Engineering draw ings of the surface and subsurfaceconstruction details of the system, incl uding design features for surge control and water hammer protection;

Proposed addition: (r ) Injection well c onstruction procedures that meet the requirements of Section 146.86;

Proposed addition: (s) Proposed area of re view and corrective action plan that meets the requirements under Section 146.84;

Proposed addition: (t) The status of corrective action on wells in the area of review;

Proposed addition: (u) A demonstration, sa tisfactory to the Director, that the applicant has met the financial res ponsibility requirements under Section 146.85;

Proposed addition: (v) Propos ed testing and monitoring plan required by Section 146.90

Proposed addition: (w) Proposed injection well plugging plan required by Section 146.92(b)

Proposed addition: (x) Proposed post-injection site care and site closure plan required by Section 146.93(a)

Proposed addition: (y) Proposed emergency and remedial response plan required by Section 146.94; and

Proposed addition: (z) Any other info rmation requested by the Director.

Proposed addition: (2) Required Class VI operation permit information

Proposed Rule: 146.82(a) & (b)

Revision or Comment: Renumber 2(a) & (b)

Proposed Rule: 146.82(d) - (h)

Revision or Comment: Renumber 2(d) - 2(h)

Proposed Rule: 146.82(h)

Proposed addition: (5) Contingency plans to cope with all shut-ins or well failures, including emergency discharge provisions;

N o rationale provided

Proposed Rule: 146.82(i)

Revision or Comment: Renumber 2(i)Proposed Rule: 146.82(j)

Proposed revision: 2(j) Results of the fo rmation testing program to obtain an analysis of the chemical, physical and ra diological characteristics of and other information on the injection zone.

N o rationale provided

Proposed Rule: 146.82(k) - (m)

Revision or Comment: Renumber 2(k) - 2(m)

N o rationale provided

Proposed Rule: 146.82(n)

Proposed revision: 2 (n) Engineering drawings of the surface and subsurface construction details of the system, incl uding design features for surge control and water hammer protection, including the following:

Proposed addition: (1) Reco rd drawings, based upon insp ections by the engineer of record or persons under his direct s upervision, with all deviations noted;

Proposed addition: (2) Copies of the mill certificates of all casings used in the construction of the well;

Proposed addition: (3) Certif ication of completion submit ted by the engineer of record;

Proposed addition: (4) An operation ma nual including emerge ncy procedures;

Proposed addition: (5) Proposed monitoring program and data to be submitted;

Proposed addition: (6) Proof that the exis tence of the well and any associated monitoring wells have been recorded with the permanent warranty deed or other instrument of conveyance as a two page proviso or addendum that contains certification of the locations of the wells (by metes and bounds) and a detailed sketch of the parcel that shows the loca tion of the well. The location shall be measured by a certified land surveyor, and shall contain the surveyor's signature, registration number, official seal, and the following statement: "I hereby certify that this su rvey was made under my re sponsible direction and supervision, and is a correct representation of the land surveyed."

N o rationale provided

Proposed Rule: 146.82(o) - (y)

Revision or Comment: Renumber 2(o) - (y)

Proposed Rule: 146.82Proposed addition: (3) Operational Testing

Proposed addition: (a) For Cl ass VI wells, the construction permit includes a
p eriod of temporary injection operation fo r the purposes of l ong term testing. Prior to commencement of operational testing:

Proposed addition: 1. Construction of the in jection well shall be complete and the permittee shall submit a notice of completion of construction to the Director.

Proposed addition: 2. Each well shall first be tested for integrity of construction, and shall be followed by a short term injection test of such duration to allow for the predic tion of the operating pressure.

Proposed addition: 3. The permittee shall submit the following information to the Director, as described in the permit.

Proposed addition: a. A copy of the borehole television survey(s) Proposed addition: b. Geophysical logs, Proposed addition: c. Mechani cal integrity test data, Proposed addition: d. Data obtained duri ng the short term injection testing conducted according to subparagraph 2. above. Proposed addition: e. Confining zone data, Proposed addition: f. Background water quality data for the injection and monitor zones; Proposed addition: g. Waste stream analysis, Proposed addition: h. As-built well construction specifications, and Proposed addition: i. Other data obtai ned during well construction which demonstrates that the well will operate in compliance with this chapter.

Proposed addition: 4. Any corrective ac tion required under Section 146.84, shall be completed.

Proposed addition: 5. Prior to granting approval for operational testing of a Class VI well, the Director shall c onsider the following information:

Proposed addition: a. All available logging and testing program data on the well; Proposed addition: b. A demonstrat ion of mechanical integrity Proposed addition: c. The anticipated maxi mum pressure and flow rate at which the permittee will operate; Proposed addition: d. The results of the formation testing program; Proposed addition: e. The actu al injection procedure; Proposed addition: f. The compatibility of injected waste with fluids in the injection zone and minerals in both the injection zone and the confining zone; Proposed addition: g. The status of correc tive action on defective wells in the area of review; and

Proposed addition: (b) Writt en authorization for operational testing shall be obtained from the Director. Authorization shal l be for up to two years or the expiration date of the construction pe rmit, whichever is less, and is onlyrenewable once as describe d in Section 146.91. The authorization shall specify the conditions under which operational testing is appr oved. The authorization shall include:

Proposed addition: 1. Inject ion pressure limitation, Proposed addition: 2. Injecti on flow rate limitation, Proposed addition: 3. Injection well monitoring requirements, Proposed addition: 4. Effluent monitoring requirements, Proposed addition: 5. Wee kly ground water sampling of monitor wells, Proposed addition: 6. Monthly sp ecific injectivity testing, Proposed addition: 7. Repor ting requirements, and Proposed addition: 8. An expiration date for the operational testing period not to exceed two years.

Proposed addition: (c ) Before authoriz ing operational testing, the Director shall conduct an inspection of the facility to determine if the conditions of the permit have been met.

Proposed addition: (d) A sampling frequency and reporting of less than once per month shall not be allowed.

Proposed addition: (e) For Class VI wells, the durat ion of the operational testing period shall not exceed two ye ars or the expiration date of the construction permit, whichever is less. If the Director has not issued an intent to issue an operation permit for the einjectionwell9s) by the end of the operational testing period, the perm ittee shall cease injection.

Proposed addition: (f) For a Class VI well , if an operation permit has not been obtained for the well within two year s after the cessation of operational testing, the permittee shall submit an a pplication to the Director to plug and abandon the well in acco rdance with Section 146.92.

Proposed addition: (4) The Director shall conduct peri odic inspections during construction

N o rationale provided

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has ma de many revisions to the GS Rule . Please see the final rule and the discussion of geologic site characterization in the pream ble for additional information.

EPA clarifies that the final rule does not require an owner or operator to obt ain a separate Class VI operational testing permit. However, EPA revised §146.82 so that the fi nal regulation specifies separate requirements for information to be submitted with the permit application and before well construction is approved (at §146.82(a)) and information to be submitted before operation of the well is authorized (at §146.82(c)). Final information on inject ion zone pressures are required fo llowing drilling of the well, at §146.82(c)(4).

EPA disagrees that the rule needs to specify the qua lifications of owner or operator staff creating the
p ermit submittals. EPA is developing a number of technical guidan ces and implementation materials to assist owners or operators and Directors in the permitting proces s. These guidances will providesuggestions on how to perform many of the activit ies necessary for applying for a permit, including developing all required plans and conducting site characterizations under §146.82. Technical guidances and implementation materials will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3560 2.2.3.2 Conditions that meri t reevaluation of the AoR (seeking comment); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Proposed Rule: 146.82(c)

Revision or Comment: Proposed Revision: 2(c ) Re-evaluation of Area of Review. After completion of the operational testing period, the Area of Review shall be re-evaluated, using a calibrated, multi- phase fluid flow model. The data collection during operational testing must be adequate for calibration of the model. If a calibrated model cannot be prepared using data collected during operational testing, the owner or operato r shall apply for a new period of operational testing of up to two years in order to collect the required data.

N o rationale provided

Response: EPA agrees that AoR reevaluations should be based on the same type of modeling that is used to perform the initial delineation, but disagr ees that the suggested ch ange is necessary. EPA clarifies that all AoR modeling (including that which supports reevaluati ons) should be based on accepted, verified, and validated scientific methods. Under requirements at §146.84(b), the owner or operator must demonstrate in the proposed AoR and corrective action plan, to the satisfaction of the Director that the modeled AoR (and all updates) will be based on detail ed geologic data collected on the site. EPA anticipates that any model that does this in a comprehensive and satisfactory manner would be approved by the Director.

Other EPA Comment Codes and Descriptions: 3120 2.1.2 Need to identify additional confining and containment zones (seeking comment) Comment: Proposed Rule: 146.83(b)

Proposed revision: (b) Owners or operators of Class VI wells must identify and characterize additional zones, if they exist, that will impede vertical fluid movement, allow for pressure dissipati on, and provide additional opportunities for monitoring, mitigation and remediation. Vertical faults and fractures that transect these zones must be identified.

Rationale: While NGWA believes that a si te with a single confining can provide storage integrity we feel that if there are additional confining layers at the site they should be characterized to get a better estimate of leakage risk to USDWs and possibly identify additional monitoring zones.

Response: EPA a g rees with the commenter that, in some si tuations, the presence of additional confinin g Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22591

Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22592and containment zones above the primary (i.e., lowermost) confining zone can improve USDW
p rotection from endangerment. The final regulation retains the requirement at §146.83(b) which affords the Director discretion to require owners or operators to identify and characterize addi tional zones. Any additional confining zones would need to be included in the geologic site characterization process, which the owner or operator would submit and the Di rector would review in determining whether to grant a permit. EPA is developing gui dance on site characterization for GS projects to assist owners or operators and Directors in eval uating permit requirements and applications under §146.82. The guidance
p rovides recommendations rega rding characterizing the regi onal geology and hydrogeology of a
p roposed GS site as well as performing the necessary geochemical, geomechanical, and geophysical analyses of the injection and confining zone. EPA expect s that this guidance will assist permit writers in making an objective decision about requiring additional confining layers . The guidance can be found on EPA’s website at http://wat er.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) Comment: Proposed Rule: 146.84(b)(2)(i)

Proposed revision: (i) The ow ner or operator will reevaluate the AOR after two yearsof operational testing (prior to i ssuance of the operating permit), and after 5 years and then no less frequently th an every 5 years for the life of the
p roject;

Rationale: NGWA believes th at a frequency of every 10 years is too long to identify early discrepancies between the site performance and the site model. Seeing early difference will allow for earlier m odel updating and provide additional reduction in leakage risk.

Response: As described above, EPA agrees that reevaluations of the Ao R every ten years may not be sufficient to ensure pr otection of USDWs from endangerment, and has changed the minimum frequency for the AoR reevaluation at §146.84(e) from 10 years to at least every 5 years in the final GS rule.

In addition, the Director has discretion to require more frequent AoR reevaluation if he or she has reason to believe, based on site-specific information, that a five -year reevaluation schedule is not sufficiently
p rotective of USDWs.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Proposed Rule: 146.84(c)(1)(i)

Proposed revision: (i) Be based on detailed geologic data collected to characterize the injection zone, confining zone(s), transmissive monitoring zones and any additional zones; and anticipated operating data, including injection pressures, rates and total vol umes over the proposed life of the geological sequestration project; Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22593

Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22595Rationale: NGWA proposes that if there ar e secondary confining units that they should be included in the site model along with any transmissive zones between the primary and secondary confining units.

Response: EPA agrees that additional confining and containment zones should be accounted for in the AoR delineation if site-specific ci rcumstances indicate a need for this. 146.84 (c)(1)(i) specifies that computational modeling should be base d on detailed geologic data collected to characterize the injection zone and confining zone, as we ll as any addi tional zones.

Other EPA Comment Codes and Descriptions: 3440 2.2.2.2 Evaluation of wells in the AoR (e.g., types of data to be reviewed) Comment: Proposed Rule: 146.84(c)(2)

Proposed revision: (2) Using methods a pproved by the Director, identify all
p enetrations, including active and abandoned wells and underground mines, in the area whose total depth is greater than th e depth to the bottom of the lowermost USDW, including those penetrating the confining zone. Provide a description of each well’s type, construction, date drilled, location, depth, record of
p lugging and/or completion, and any additi onal information the Director may require; and

Rationale: This makes this consistent with NGWA's proposed section 146(a)(8)

Response: EPA clarifies that any well that penetrates th e confining zone, even if it does not extend all the way through the confining formation, is to be included in the tabulation. EPA is issuing guidance on. The guidance describes EPA's recommended approaches fo r the data to be considered in an initial AoR delineation, how to apply computational modeling to de lineate the AoR, how to identify all wells that require corrective action, performing corrective action at GS sites, a nd, when appropriate, completing AoR reevaluations. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

The final rule retains the language in §146.84(c)(2) as proposed. EPA clarifie s that the mapping and cross sections required to be submitted under §146.82(a)(3 ) will define the limits of the confining zone, which would be accounted for in the AoR delineat ion and corrective action evaluation required at §146.84(c). EPA adds that owners or operators must also, under §146.82(a)(2), submit a map of the AoR that shows all injection wells, producing wells, abandoned wells, plugged we lls or dry holes, deep stratigraphic boreholes, State or EPA approved subsurface cleanup sites, surface bodies of water, springs, mines (surface and subsur face), quarries, water wells and other pertinent surface features including structures intended for human occupancy and roads. EPA be lieves that these requirements address the commenter's concerns.

Other EPA Comment Codes and Descriptions: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) Comment: Proposed Rule: 146.84(f) Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22596

Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22597Proposed revision: (f) At the minimum fi xed frequency, not to exceed two years if under operational testing (prior to i ssuance of the operating permit), or 5 years (if operating permit has been issued), as specified in the area of review and corrective action plan or when monitoring and operational conditions warrant, owners or operators must:

Rationale: This makes this consistent wi th NGWA's proposed revision to Section 146.84(b)(2)(i)

Response: EPA agrees that reevaluations of the AoR every ten years may not be sufficient to appropriately model plume and pre ssure front movement, establish c onditions for corrective action, and ensure protection of USDWs from endangerment. Fo r these reasons, the Agency changed the minimum frequency for the AoR reevaluation at §146.84(e) from 10 years to at least every 5 years in the final GS rule. EPA believes that this revised frequency a ddresses commenters' concer ns about the inherent uncertainties in modeling CO2 movement, the emerging nature of GS technology, risk-based targeting of monitoring activities, and the unique nature of CO2 GS. In addition, the Di rector has discretion to require more frequent AoR reeval uation if he or she has reason to believe, based on site-specific information, that a five -year reevaluation schedule is not sufficiently protective of USDWs.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Proposed Rule: 146.85(b)

Proposed revision: (b) The owner or operato r must provide to the Director, at the same frequency as the AOR reevalua tion, written updates of adjustments to the cost estimate to account for any am endments to the area of review and corrective action plan (§146.84), the in jection well plugging plan (§146.92), and the post-injection site care a nd site closure plan (§146.93).

Rationale: NGWA proposes that potential changes in the size of the AOR require that all site plans be reevaluated at the same frequency as the AOR.

Response: EPA agrees that it is important to periodical ly update cost estimate s that support financial responsibility determinations. EP A clarifies that the GS rule, at §146.85(c) requires the owner or operator to provide annual updates to the cost estima te to account for any amendments to the AoR and corrective action plan, the inject ion well plugging plan, the PISC and site closure plan, and the emergency and remedial response pla n. See the final rule and preamble for further discussion of EPA's final approach to financial responsibility. EPA adds that the Director can also require the owner or operator to provide an adjustment of the cost estimate if the Director determines that the original demonstration is no longer adequate , as specified at §146.85(e). The owne r or operator must also update the cost estimate annua lly to adjust for inflation under §146.85(c)(2).

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Proposed Rule: 146.87(a)(3)(ii) Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22599

Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22604Proposed revision: (ii) A cement bond, vari able density log, and radial cement evaluation log and a temperature log after the casing is set and cemented.

Rationale: NGWA supports inclusion of a radial cement evaluation log in addition. The addition of this test will help identify any potential channels in the cement out from casing

Response: EPA clarifies at §146.87(a)(2)(ii) that owners or operators must perform a cement bond (i.e., cement evaluation) log after the casing is set and cemented.

Other EPA Comment Codes and Descriptions: 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: Proposed Rule: 146.89(c)

Proposed revision: At least once per year , the owner or opera tor must use one of the following methods, as approved by th e director, to determine the absence of significant fluid movement under pa ragraph (a)(2) of this section.

Rationale: There was a question as to whet her one of these tests individually would suffice in all circumstances. The change proposed is to allow the director to review the proposal.

Response: EPA clarifies that all MITs the owner or operator proposes to use must be described in the
p roposed testing and monitoring plan, which must be approve d by the Director. See §146.90. EPA believes that the MITs described in §146.89(c) of the rule (e.g., an approved tracer log or temperature or noise logs) are effective methods to demonstrate external MI, provide an important early warning of
p otential problems in the injection well system, and represent standard techniques that have been used successfully by the drilling industry and for the UI C Program for decades. The Agency notes that the regulations do provide the Director flexibility at §146.89(e) to approve the use of alternative MIT methods.

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: [In the text below, text in CAPS denotes added text.]

Proposed Rule: 146.90(h)(1)

Proposed revision: (1) The testing and monitoring plan must be based on
p otential RISKS within the area of review;

Rationale: Risk is more generally accepted and understood.

Response: The final rule at §146.90(h)(1) incorporates th e suggested revision. Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22606

Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22609made many revisions to the GS ru le. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Proposed Rule: 146.91

Proposed addition: (1) Class VI Test/I njection Well Cons truction Permit

Proposed addition: (a) The Director shall require periodic data reports and
p rogress reports during cons truction that include:

Proposed addition: 1. Driller's log Proposed addition: 2. Geophysical surveys Proposed addition: 3. Core analyses Proposed addition: 4. Lithologic logs Proposed addition: 5. Drill stem tests Proposed addition: 6. Pump tests Proposed addition: 7. Daily j ob (construction) reports Proposed addition: 8. Water quality analyses

Proposed addition: (b) The frequency of reporting shall be sp ecified in the individual permit

Proposed addition: (c ) Interpretation of data is required in the data reports or progress reports at the completion of each significant phase of construction, such as completion of test well c onstruction and testing, completion of injection well construction, and comp letion of injection well testing.

Proposed addition: (d) The owner or operato r shall submit final reports of all data collected from the test injection ell with interpretations to the Director with the application for a Class VI Test /Injection Well Constr uction and Testing Permit and a Class VI Injection Well Operation Permit shall include all information and data collected unde r Section 146.87, with appropriate interpretations

Proposed addition: (2) Class VI Operational Testing Permit

Proposed addition: (a) The owne r or operator shall submit, as part of the permit application, the proposed methodology for collection and reporting of operational data, to ensure that the data is collected, correlated, and reported in a fashion that would enable the Dir ector to evaluate well performance.

Proposed addition: (b) All Class VI well s shall report monthly the following:

Proposed addition: 1. Operating re ports to the Director on:

Proposed addition: a. The ph y sical, chemical, and other relevant Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22610characteristics of injection fluids;

Proposed addition: b. Daily reading of the pressure and flow for each well. For each Class VI sequestration well, a specific injectivity test shall be performed quarterly;

Proposed addition: c. Monthly average, ma ximum and minimum values for injection
p ressure, flow rate and volume, and annular pressure; and

Proposed addition: d. The re sults of monitoring pres cribed under Section 146.90

Proposed addition: 2. Reporting the result s, within three months after the completion of:

Proposed addition: a. Annular monitori ng tests of mechanical integrity;

Proposed addition: b. Any other test of the injection ell conducted by the
p ermittee if required by the Director; and

Proposed addition: c. A ny well work over.

Proposed addition: (c ) Speci fic injectivity testing shall be performed while the pumping rate to the well(s) has been set at a predetermined level and reported as the specific injectivity inde x (gpm/specific pressure (psig)). As
p art of this test, the well shall be s hut-in for a period of time necessary to conduct a valid observation of pressure fa ll-off. The owner or operator shall
p ropose which pumping rate will be used based on the expected flow, the design of the pump station including the volume of the wet well and pump type(s), and the type of pump controls used. The pum ping rate(s) shall be included as a condition of the operation permit.

Proposed addition: (d) Re-eva luation of Area of Review. After completion of the operatonal testing period, the Area of Revi ew shall be re-evaluated, using a calibrated, multi-phase fluid flow model. The data collection during operational testing must be adequate fo r calibration of the model. If a calibrated model cannot be prepared us ing data collected during operational testing, the owner or operator shall a pply for a new period of operational testing of up to two years in order to collect the required data. No more than two operational testing permits can be is sued for any Class VI well. If the recalculated Area of Review includes any relevant wells or penetrations through the confining zone that were not reported in the permit application, a new tabulation of penetrations as required in Section 146.84(c)(2) and (3) shall be
p rovided. Owners or operators must perf orm corrective action as required in Section 146.84(d).

Proposed addition: (e) If phys ical or geochemical data such as water quality,
p ressure changes, or mechanical integr ity test results indicate that fluid movement into or between underground sources of drinking water may be occurring, the permittee shall submit additional data to provide reasonable assurance that the injection operation is in compliance wi th the requirements of this chapter. This additional data shall be submitte d with the periodic operations reports,the content and frequency of which ar e specified in the individual permit.

Proposed addition: (f) A Class VI well permit shall be written to require that if CFR Section 146.14(a) is applicable, pr ogress reports shall be submitted no later than thirty days following each interim date and the final date of compliance.

Proposed addition: (3) Class VI In jection Well Oper ation Permit.

Proposed addition: (a) The applicant shall submit, as part of the permit application, the proposed methodology for collection and reporting of operational data, to ensure that the data is collected, correlated, and reported in a fashion that would enable the Dir ector to evaluate well performance.

Proposed addition: (b) All Class VI well s shall report monthly the following:

Proposed addition: 1. Operating re ports to the Director on:

Proposed addition: a. The physical, chemical, and other re levant characteristics of injection fluids;

Proposed addition: b. Daily readings of th e pressure and flow for each well. For each Class VI well, a specific in jectivity test shall be performed quarterly;

Proposed addition: c. Monthly average, ma ximum and minimum values for injection
p ressure, flow rate and volume, and annular pressure; and

Proposed addition: d. The re sults of monitoring pres cribed under Section 146.90

Proposed addition: 2. Reporting the result s, within three months after the completion of:

Proposed addition: a. Periodic test s of mechanical integrity;

Proposed addition: b. Any other test of the injection well conducted by the
p ermittee if required by the Director; and

Proposed addition: c. A ny well work over.

Proposed addition: (c ) Speci fic injectivity testing shall be performed while the pumping rate to the well(s) has been set at a predetermined level and reported as the specific injectivity inde x (gpm/specific pressure (psig)). As
p art of this test, the well shall be s hut-in for a period of time necessary to conduct a valid observation of pressure fa ll-off. The owner or operator shall
p ropose which pumping rate will be used based on the expected flow, the design of the pump stations including the volume of the wet well and pump type(s), and the type of pump controls used. The pum ping rate(s) shall be included as a condition of the operation permit.

(d) Re-evaluation of Area of Review. Every five years, th e Area of Review shallb e re-evaluated, using a calibrated, mult i-phase fluid flow model. The data collection during operation must be adequate for calibration of the model. If a calibrated model cannot be prepared usi ng data collected during operation, the owner or operator shall, within 90 days, apply for a new operation permit with a revised monitoring and testing plan desi gned to collect the required data. The re-issued Class VI operation permit shall be valid for a period of no more than two years. After two years of operation under a re-issued operating permit, the applicant shall again re- evaluate the Area of Review using a calibrated, multip hase fluid flow model and re-apply for a five-year operating permit. If the recalculated Area of Review includes any relevant wells or pe netrations whose total depth is greater than the depth to the bottom of the lowermost USDW that were not reported in the permit application, a new tabulation of penetrations as required in Section 146.84(c)(2) and (3) shal l be provided. Owners or operators must perform corrective action as requi red in Section 146.84(d) must perform corrective action as required in Section 146.84(d).

N o rationale provided

Proposed Rule: Introductory te xt to 146.91 and 146.91(a)(1)-(4)

Revision or comment: Proposed for deletion

Rationale: Covered in proposed Se ction 146.91(3) and subsections

Proposed Rule: 146.91(a)(5)

Revision or comment: Renumber 3(e)

Proposed Rule: 146.91(a)(6)

Revision or comment: Renum ber 3(f); delete "and"

Proposed addition: (g) If phys ical or geochemical data such as water quality,
p ressure changes, or mechanical integr ity test results indicate that fluid movement into or between underground sources of drinking water may be occurring, the permittee shall submit additional data to provide reasonable assurance that the injection operation is in compliance wi th the requirements of this chapter. This additional data shall be submitte d with the periodic operations reports, the content and frequency of which are specified in the individual permit.

Proposed addition: (h) A Class VI well per mit shall be written to require that if CFR Section 146.41(a) is applicable, pr ogress reports shall be submitted no later than thirty days following each interim date and the final date of compliance.

N o rationale provided

Proposed Rule: 146.91(a)(7); 146.91(b)(1)-(3)

Proposed for deletionRationale: Covered in proposed Section 146.91(3) and subsections

Proposed Rule: 146.91(c)

Renumber (4)

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approac h. EPA is developing guidances on injection well construction and on monitoring and te sting that will assist owners or operators and Directors in
p erforming the pre-operati onal logging and testing required at §146.86. This guidance will be available on EPA’s website at http://w ater.epa.gov/type/groundwater/u ic/wells_sequestration.cfm.

As described above, EPA clarifies that the final rule does not require an owner or operator to obtain a separate Class VI operational test ing permit. However, EPA revised §146.82 so that the final regulation specifies separate requirements for information to be submitted with the permit application and before well construction is approved (at §146.82(a)) and information to be submitted before operation of the well is authorized (at §146.82(c)). Final information on injection zone pressures are required following drilling of the well, at §146.82(c)(4).

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care Comment: Proposed Rule: 146.92(b)

Proposed revision: (b) Well Plugging Plan. Th e owner or operator of a Class VI well must prepare; maintain; includi ng updating on the same schedule as the update to the Area of Review; and comply with a plan that is acceptable to the Director. The requirement to maintain and implement an approved plan is directly...

Rationale: The Area of Review re-evaluation should trigger a review and updating of all the plans (MMV, financial, pluggi ng, emergency response...) on the same interval that the AOR is updated. NGWA suggests EPA check all timelines and make them compatible.

Response: EPA agrees that the AoR reevaluations of fer a good opportunity to promote a dialogue between the owner or operator and the permitting authority. A dditionally, EPA recognizes that the AoR reevaluation has the potential to cha nge or add important data to the ot her project plans and therefore the Agency agrees that the other Class VI plans must be updated when an AoR reevaluation takes place. The final GS rule, at §§146.84(c), 146.90(j), and 146.94(d), re quires owners or operators to review and update the AoR and corrective action plan, the te sting and monitoring pla n, and the emergency and remedial response plan throughout the life of the pr oject. Owners or operators must review each plan and identify necessary amendments to the plan or demonstrate to the Director that no amendment is needed. These reviews must be performed within one year of an AoR reevaluation, following any significant changes to the facility (e.g., the addition of monitoring or injection wells), or when required by the Director. In no case can review s occur less often than once ever y five years. EPA is preparing guidance for owners or operators on developing and updating all of the required GS project plans. The
g uidance will be available on EPA's web site, at Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22611http://water.epa.gov/type/groundwater/u ic/wells_sequestration.cfm. See th e final rule and preamble for further discussion on EPA's final approach regarding the GS project plans.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Proposed Rule: 146.92(d)

Proposed revision: (d) Plugging Reports fo r Class VI Wells. Within 60 days after completion of plugging and abandonmen t of a well or well field the
p ermittee shall submit to the Direct or a final report which includes:

Proposed addition: (1) Certification of completion in accordance with approved
p lans and specifications by an appropriate ly qualified engineer of record or
p rofessional geologist.

N ote: It is important that the engineer and/or geologist ha ve expertise and training in injection well drilling t echnology, reservoir characterization and injection well construction and operation.

Proposed addition: (2) Evidence, such as a sealed copy or certification from the county clerk, that a surveyor's plot of the location of the abandoned well has been recorded in the county courthouse property records.

Response: EPA agrees that appropriately qualified personnel (e.g., engineers and geologists) should be involved in all aspects of the GS operation, includi ng the well plugging process. When the owner or operator (and/or the person who performs the plugging operation) signs the pluggi ng report and certifies it as accurate; they are attesting to the fact th at all required activities were performed by qualified
p ersonnel. This is required under §146.92(d) and is a condition of the permit th at is enforceable under §1423 of the SDWA. EPA clarifies that, in addition to requiring appropriate well plugging, the Director retains the option of witnessing any plugging activity or testing at the well.

EPA clarifies that §146.93(g) requires the owner or operator, as part of the closure process, to record a notation on the deed stating that the property was used for GS . In addition, §146.93( f)(1) requires submission of a survey plat indicati ng the location of the well to the lo cal zoning authority, as well as to the Director.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5220 2.8.2.1 Post -injection monitoring activities Comment: Proposed Rule: 146.93(a)

Proposed revision: (a) The owner or operato r of a Class VI well must prepare; maintain; including updating on the same sche dule as the update to the Area of Review; and comply with a plan for post -injection site care and site closure that meets the requirements of para g raph (a)(2) of this section and is Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22612

Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22613acceptable to the Director.

Rationale: The Area of Review re-evaluation should trigger a review and updating of the well plugging plan, and the post in jection site care and closure plan. N GWA suggests EPA check all timeline s and make them compatible.

Response: EPA agrees with the commenter that, in some cases, the appropr iate post-injection monitoring strategy may end up being different than init ially projected at the time of permit application and there may be a need to amend th e post-injection site care and site closure plan. EPA is requiring that upon the cessation of injection, the owner or operator submit an amended post-injection site care and site closure plan or demonstrate to the Director that no changes to th e original post-inj ection site care and site closure plan ar e necessary, as specified in §146.93(a)(3). EPA is not requiring formal periodic review and updates to the PISC and site closur e plan throughout the injection phase. EPA does not expect that changes to this plan would be implemented until injection operations cease. EPA envisions that owners or operators will take into account similar c onsiderations that guide updates to other project
p lans, e.g., monitoring and operational data and results of AoR reevaluations.

EPA has also added a new provision at §144.39(a)(5) requiring a modification, re vocation, or reissuance of a Class VI permit whenever the Di rector determines that a change in the permit is necessary based on an amended AoR and corrective action plan, testing and monitoring plan, inje ction well plugging plan,
p ost-injection site care and site closure plan, or emergency and remedial response plan is necessary. This would invoke the public notification procedures of 40 CFR Part 124 and th e modification would be incorporated into the permit. EPA adds that, if a ny monitoring or other site data indicate a need for amending the post-injection site care plan, the owner or operator is expected to amend the plan accordingly.

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: Proposed Rule: 146.93(b)(1)

Proposed revision: (1) The owner or operator shall continue to conduct monitoring as specified in the Director-approved post-injecti on site care and site closure plan for at least 30 year s following the cessation of injection. At the Director's discretion, the monitori ng will continue until the geologic sequestration project no longer poses an endangerment to USDWs.

Rationale: NGWA believes some number should be included. 30 years is a number used in other EPA programs. The next que stion was whether the burden should be
p laced on the director to justify the l onger number or on the operator to prove the site is stabilizing. It is suggested that the director be allowed to approve both a shorte r or longer timeframe. With the next subsection, the burden is placed on the owner or operato r to prove a shorter timeframe is acceptable, while allowing in this subsect ion the director to require monitoring beyond 30 years.

Proposed Rule: 146.93(b)(2)

Proposed revision: (2) If the owner or operator can demonstrate to the Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22614satisfaction of the Director that th e geologic sequestrati on project no longer
p oses an endangerment to USDWs, the Dire ctor may approve an amendment to the
p ost-injection site care and site closur e plan to reduce the frequency of monitoring or may authorize site closure before the e nd of the 30-year period.

Rationale: Makes this subsection compatib le with 30 year timeframe proposed by N GWA in 146.93(b)(1)

Response: EPA disagrees that a post-injection site care timeframe of 50 years is excessive for most Class VI wells. EPA proposed a defa ult post-injection site care timefr ame of 50 years based on a review of research studies, industry reports , and existing environmen tal programs. This analysis was included in an EPA-prepared background document that is available in the fede ral docket, titled "Computational Modeling of Underground In jection of Carbon Dioxide for Dete rmination of Area-of-Review and Potential Risk to Underground Sources of Drinking Water." EPA assessed various default timeframes based on additional review of re search studies and evaluation of public comments. While numerous commenters suggested that EPA shorten the monito ring timeframe, none of the commenters provided sufficient data or other evidence to warrant a ch ange in the proposed time frame. While the 10- or 30- year timeframe suggested by some of these commenters may be within the timeframe suggested in some studies, EPA believes that the potential risks of e ndangering USDWs will likely not decline within these timeframes and available data, including data submitted by commenters, do not support a different default timeframe. However, EPA recognizes th at there may be sites where the 50 year post injection site care timeframe may be either not appropriate or more burdensome than necessary based on site-specific conditions. For this reason, the GS rule offers owners or operators flexibilit y regarding the duration of the PISC timeframe by: (1) allowing the Direct or discretion to shorten or lengt hen the PISC timeframe during the
p ost-injection period based on site-specific data, pursuant to requi rements at §146.93(b); or (2) affording the Director discretion to allow a Class VI well ow ner or operator to demonstr ate, during the permitting
p rocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c). EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mon itoring and USDW impacts, as the commenter suggests.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: Proposed Rule: 146.94(a)

Proposed revision: (a) As part of the pe rmit application, the owner or operator must provide the Director with an emer gency and remedial response plan that describes actions to be taken to address movement of the injection or formation fluids that may cause an endangerment to a USDW during c onstruction, operation, closure and post-closure periods. The emerge ncy and remedial response plan must be reviewed and updated, as necessary, on th e same schedule as the update to the Area of Review. Commenter Name: Christine Reime r Letter ID: 0142 Commenter Or g anization: National Ground Water Association Comment ID: 22615Rationale: Keep same update schedule as AOR

Response: In response to comments on the duration of th e emergency and remedial response plan, EPA clarifies that the plan will apply over the life of the GS project thr ough the post-injection site care period (§146.94(a)). EPA has added a requirement at §146.94(d) that owners or operators must review their emergency and remedial response plan within one year of an AoR reevaluation required under §146.84 or following significant changes to the facility. Subsequently, owners or operators must submit an amended plan or demonstrate to the Director that no amendment to th e plan is needed based on the AoR reevaluation or any significant ch anges made to the facility.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: 146.83 (a) (1): MDEQ suggests adding the sa me language to (1) as is found in (2): "without initiating or propagating fractures in the injection zone.

Response: EPA did not make the suggested edit to the injection zone requirement but retained similar language in the restriction on in jection pressure at §146.88(a).

Comment: §146.81 Applicability. (b) "This subpart applies to wells used to inject carbon dioxide specifically for the purpose of ge ologic sequestration, i.e., the longterm containment of a gase ous, liquid or supercritical carbon dioxide stream in subsurface geologic formations."

We recommend striking out "gaseous, liquid or supercritical carbon dioxide stream" and replacing with "gaseous, liquid, supercriti cal or co-mixed carbon dioxide stream" This change will allow fo r injection of carbon dioxide that is
p re-dissolved with water to prevent phase separation in the injection zone or with inclusion of flow or pum ping enhancement components.

Response: EPA disagrees with the suggested change. EPA believes that this paragraph, along with the definition of a CO2 stream at §146.81( d), appropriately convey the allo wable injection activities that may be permitted as Class VI. For additional inform ation on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: 146.82 Required Class VI permit informati on. (b) "A map showing the injection well(s) for which a permit is sought and the applicable area of review. Within the area of review, the map must show th e number, or name and location of all in

j ection wells, producin g wells, abandoned wells, plu gg ed wells or dr y holes, Commenter Name: Bonnie Lovelace Letter ID: 0152 Commenter Or g anization: Montana Department of Environmental Quality (MDEQ) Comment ID: 22126

Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technolo g ies Council (GTC) Comment ID: 23768

Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technolo g ies Council (GTC) Comment ID: 23769deep stratigraphic boreholes , State or EPA approved s ubsurface cleanup sites, surface bodies of water, springs, mine s (surface and subsurface), quarries, water wells and other pertinent surface f eatures including structures intended for human occupancy and roads. The map should also show faults, if known or suspected. Only information of public reco rd is required to be included on this map; "

The note that "only information of public record is required to be included on this map" may leave out deep oil and gas wells, particularly older wells. The
p resence of such non-public but "known" information may be eligible for inclusion as "known" under 144.55(a).

Response: EPA believes that a determination about whethe r or what information may be necessary (for a specific GS project) is outside of the public record will be site-s pecific and based on knowledge of the site, data availability, and data quality. For instance, in meeting the requirement to tabulate information on wells in the AoR, the Director has the discreti on to require the owner or operator to supplement a data records search if there is re ason to believe that the incomplete ness of available information could compromise USDW protection from endangerment.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: §146.82 Required Class VI permit information (e) "A ta bulation of all wells within the area of review which penetrate the injecti on or confining zone(s). Such data must include a description of each well's type, construction, date drilled, location, depth, record of plugging and/or completion, and any additional information the Director may require; -

We recommend striking out "all wells" and replacing with "all known wells".

Requiring that all wells or other artifici al penetrations into injection or confining zones within the AoR be iden tified and information on depth and closure be provided can be costly and sometimes accurate information is difficult to obtain for older wells with in the AoR. EPA's assistance in obtaining and storing this information w ould be helpful to CCS operators.

Response: The Agency believes that the requirement to provide a tabulation of wells and geologic information (at §146.82(a)), al ong with a description of each well's type, construction, date drilled, location, depth, record of plugging and/or completion will appropriately inform a determination of the risk associated with wells in the AoR. EPA believes that it is important to ha ve information on all wells in the AoR.

Other EPA Comment Codes and Descriptions: 3330 2.2.1.3 Applicability /adequacy of computational models (seeking comment) Comment: §146.84 Area of review and corrective action. (c) (1) "Predict, using computational modelin g , the pro j ected lateral and vertical mi g ration of the Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technolo g ies Council (GTC) Comment ID: 23770

Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technolo g ies Council (GTC) Comment ID: 23771carbon dioxide plume and formation fl uids in the subsurface from the commencement of injection ac tivities until the plume move ment ceases, pressure differentials sufficient to cause the move ment of injected fluids or formation fluids into a USDW are no longer presen t, or after a fixed time period as determined by the Director."

We recommend striking out "Predict, using computational modeling, the protected lateral and vertical migration of the carbon dioxide plume" and replacing with "Using computational modeling, provide prot ected potential ranges of lateral and vertical migration of the carbon dioxide plume" The use of multiphase groundwater flow and transpor t models is to predict the composition and movement of each phase state (e.g., liquid, gas ,s upercritical fluid) of CO2 in the subsurface, as well as fluid pressures, to define the AoR. One of the concerns with the use of such complex models is that the site may not be fully characterized with respect to hydro- geologic properties. There may be significant uncertainty in one or mo re hydraulic proce sses/parameters. Therefore, it is possible to obtain a wide-range of model outcomes from different model parameters. The uncertainty in model pa rameters and sensitivity of model results to parameter selection should be addressed.

Response: EPA has clarified this language in the final rule . It now reads, “Predi ct, using existing site characterization, monitoring and operational data, and computational modeling, th e projected lateral and vertical migration of the carbon dioxide plume and formation fluids in the subsurface from the commencement of injection activities until the plum e movement ceases, until pressure differentials sufficient to cause the movement of injected fluids or formation fluids into a USDW are no longer
p resent, or until the end of a fixed time period as determined by the Director.”

EPA agrees that modeling results are prone to varied degrees of uncertainty. As discussed in the
p reamble to the proposed GS regulation and th e associated background document "Computational Modeling of Underground In jection of Carbon Dioxide for Dete rmination of Area-of-Review and Potential Risk to Underground Sources of Drinking Water" (cited in the proposed rule preamble as USEPA, 2008d), model predictions depend largely on the values of key parameters. Often these
p arameter values are estimated or av eraged from several data sources. EPA also agrees that sensitivity analyses and "worst case scenario " modeling runs should be presented by the owner or operator and evaluated by the Director. If during the permit review, the Director de termines that modeling results are too wide-ranging, further info rmation will be required of the owner or operator.

EPA clarifies that models are tools to help predic t the movement of a CO2 plume over long time frames. However, EPA recognizes that it cannot be expected that modeling something as complex as a CO2
p lume can be done with complete certainty; therefore EPA is also requiring that the AoR be reevaluated to verify the CO2 plume is movi ng as predicted and to allow for model calibration and necessary revisions to the required GS project plans (e.g., AoR and corrective action, testing and monitoring, injection well plugging, post-in jection site care and site closure, and emergency and re medial response). EPA believes that near-term predictions (e.g., over the subse quent 5 years) will ha ve the highest degree of certainty. Periodic model calibration will allow refinement to th e AoR delineation based on realworld conditions and operati ng data and monitoring results, and t hus increase confidence in the modeled
p redictions. EPA adds that the final GS regulation includes a requirement at §146.84(e) that the AoR be reevaluated at least every 5 years (an adjustment from the ten year interval in the proposal), which should further address the commenters' c oncerns regarding model uncertainty.Other EPA Comment Codes and Descriptions: 3440 2.2.2.2 Evaluation of wells in the AoR (e.g., types of data to be reviewed) Comment: §146.84 Area of review and corrective acti on. (c) (2) "Using methods approved by the Director, identify all penetrations , including active and abandoned wells and underground mines, in the area of revi ew that may penetrate the confining zone. Provide a description of each well 's type, construction, date drilled, location, depth, record of plugging a nd/or completion, and any additional information the Director may require; and ..."

We recommend striking out "approved" and replacing with "prescribed". We recommend deleting the second sentence and replacing with "Where such information is available or can be obtained, provide a description of each well's type, construction, date drille d, location depth record of plugging and/or completion and any additional inform ation prescribed by the director and ..." Acceptable methods for identifying de ep wells into confining zones within the AoR should be prescribed by the EPA as part of the regulation. Accurate information is difficult to obtain for olde r wells within the AoR. Examples of other information that could be require d by the Director should be clearly stated.

Response: EPA is retaining the language in §146.84(c)(2) as proposed. Based on its evaluation of all
p ublic comments and input on the proposed rule and NODA and Request for Comment, EPA has made many other revisions to the GS Rule. See the final rule and preamble for further discussion on EPA's final approach.

EPA acknowledges that public records may not contain data on every artificial penetration in the AoR (or all of the data on each well that is required for the tabulation), particularly in areas with many older wells. However, the Agency rec ognizes that there may be situations where additional surveys or research to locate information on wells may be appr opriate. For example, there may be cases where the Director may determine that ground or airborne survey s for wells are appropriate , e.g., if there is reason to believe that the incompleteness of informati on on known wells could compromise USDW protection from endangerment. In order to preserve the Director's discretion to require an operator to supplement a records search, EPA did not make the suggested cha nge. EPA adds that all corrective action must be
p erformed pursuant to the approved AoR and correct ive action plan, which affords the Director the discretion to require any additional information needed (including information that may not be
p ublically available) to ensure that all necessary corrective action is perfor med. The guidance describes EPA's recommended approaches for the data to be considered in an initial AoR delineation, how to apply computational modeling to deli neate the AoR, performing corrective action at GS sites, and, when appropriate, completing AoR reevaluations. The guida nce will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm

Other EPA Comment Codes and Descriptions: 3822 2.3.1.1 Depth of surface casing (seeking comment) Comment: §146.86 Injection well construction requireme nts. (b) (2) "Surface casing must extend through the base of the lowermost USDW and be cemented to the surface. " Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technolo g ies Council (GTC) Comment ID: 23772

Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technolo g ies Council (GTC) Comment ID: 23773We recommend striking out this requireme nt in its entirety. This will be
p rohibitively expensive in deep wells, and may not be necessary at all sites.

Response: EPA disagrees that protecting deep USDWs underlying multiple, more shallow USDWs is unnecessary. Protection of USDWs, regardless of their depth or strati graphic location, is the primary mission and mandate of the UIC program—as specified by Congress in the SDWA—and the purpose of all requirements for injection wells . Any injection activity must be demonstrated to not endanger USDWs, regardless of their depth, and if such a dem onstration cannot be made, th en the activi ty will not be allowed under UIC requirements or the SDWA. Water agencies commenting on the proposed rule noted that diminishing water supplies are requiring water utilities to use deeper and more saline sources, and the SDWA mandates EPA to set regulations that protect USDWs from endangerment.

The final GS rule at §146.86(b)(2) requires that surf ace casing extend through the base of the lowermost USDW and be cemented to the surf ace through the use of a single stri ng or multiple strings of casing and cement. It does not, however, specify how cementi ng must be accomplished, and it allows the owner or operator to propose altern ate methods that provide a sufficient am ount of cement to meet the standard that USDWs are protected from endangerment. EPA not es that there are many potential ways to meet the requirement, such as th e use of staged cementing.

EPA recognizes concerns re garding construction of Class VI well s where the lowermost USDW is very deep. To further address comments on deep inje ction wells, the final GS rule at §146.95 includes requirements for owners or operators that seek a waiv er of the injection depth requirements. Owners or operators of wells operating under in jection depth waivers must comp ly with additional construction requirements to ensure that wells used to inject above or between USDWs are protective. See the discussion of the waiver approach in the preamble to the final GS rule for additional information.

Other EPA Comment Codes and Descriptions: 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment); 4660 2.6.6 Geochemical monitoring Comment: §146.90 Testing and monitoring requirements. (d) Periodic monitoring of the ground water quality and geochemical cha nges above the confining zone(s) that may be a result of carbon dioxide move ment through the confining zone or additional identified zones:

We recommend changing to "Periodic monitoring of the ground water quality and geochemical changes between the confining zone(s) and the USDW that may be a result of carbon dioxide movement through the confining zone or additional identified zones:" This rewording is consistent with allowing for injection either above or below USDWs

Response: EPA disagrees that the GS rule should specify the zones to be monitored. EPA clarifies that §146.90(d) requires periodic monitoring of the ground wa ter quality and geochemical changes above the confining zone(s). EPA clarifies that this monito ring requirement does not in clude the confining layer itself. Monitoring above the confin ing layer will provide an indicati on of upward movement of CO2 that might endanger a USDW. The exact numbe r of formations to be tested will, however, be based on sitespecific characteristics a nd vulnerabilities and described in the Director-approved testing and monitoring
p lan.

EPA is developin g g uidance on testin g and monitorin g to assist owners or ope rators and Directors in Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technolo g ies Council (GTC) Comment ID: 23774evaluating requirements under §146.90, in cluding proposed monitoring pl ans. The guidance describes available technologies and recommended approaches for implementing a test ing and monitoring plan, including pre-operational geophys ical logging and test ing of injection wells, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

In the final GS rule, owners or operators granted injection depth waivers are subject to additional requirements at §146.95(f)(3) to monitor above and below the injection zone in order to ensure
p rotection of USDWs underlying and overlying the injection zone during both well operation and the
p ost-injection site care period.

For additional information on the waiv er approach, please se e the final rule and preamble, as well as EPA's responses to comments on the Notice of Da ta Availability and Request for Comment.

Other EPA Comment Codes and Descriptions: 4650 2.6.5 CO2 plume and pressure front tracking (seeking comment) Comment: §146.90 Testing and monitoring requirements. (g) "Testing and monitoring to track the extent of the carbon dioxide plume and the position of the pressure front by either monitoring for pressure ch anges in the first formation overlying the confining zone or using indirect , geophysical techniques (e.g., seismic, electrical, gravity, or elec tromagnetic surveys and/or down-hole carbon dioxide detection tools); -

We recommend deletion of this requirement in its entirety and replacing with "Testing and monitoring to track the ex tent of the carbon dioxide plume." Tracking the precise position of a moving pressure front will require a large number of expensive and deeply located probes. A limited number of pressure monitors that can provide information on pressures affecting the confinement layers are more valuable. The Proposed Rule also requires well owners to monitor
p eriodically groundwater quali ty and geochemical changes above the confining zone. The requirements for such deep m onitor wells could be costly. Requiring both pressure and geochemical monitoring wi ll be costly and provide questionable additional information or warning.

Response: EPA maintains that plume tracking and pr essure monitoring are key components of monitoring at GS sites. A rigorous plume tracking and pressure monitoring scheme, such as one that meets the requirements at §146.90(g), is imperative for ensuring that th e CO2 plume is contained within the injection zone.

The final rule (at §146.90(g)) requires owners or operato rs to perform monitoring to track the extent of the CO2 plume and pressure front. The owner or ope rator must use direct methods to monitor for
p ressure changes in the injection zone. Indirect methods (e.g., seismic, electrical, gravity, or electromagnetic surveys and/or down- hole CO2 detection tools) are also required unless the Director determines, based on site-specific geology, th at such methods are not appropriate

Pressure monitorin g in the in j ection zone is necessar y to track the developmen t and movement of the Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technolo g ies Council (GTC) Comment ID: 23775p ressure front and CO2 plume. When combined with in formation on temperature, pressure data provide an indication of the phase (e.g., ga s, supercritical) and distribution of the injected CO2 (73 FR 43515). Monitoring can also identify needed remedial ac tions, provide inputs for AoR reevaluation modeling, evaluate predictions of plume movement, and ta rget additional geochemi cal and surface monitoring needs.

EPA recognizes that installation of monitoring wells entails additiona l resources. However, the Agency believes that such monitoring is necessary to ensu re that GS projects are appropriately operated and monitored and to protect USDWs from endangerment. EPA believes that pressure monitoring in the injection zone is necessary to track the developm ent and movement of the pressure front and CO2
p lume. Monitoring can also identify needed reme dial actions, provide inputs for AoR reevaluation modeling, evaluate predictions of plume movement , and target additional geochemical and surface monitoring needs. Knowledge of the location of the CO2 plume and the associated pressure front will assure the public that GS projects are proceeding accord ing to plan, provide sufficient information to the owner or operator and Director, or allow for appropriate actions to address any indication that USDWs may be endangered.

The combination of site characterization and pr edictive modeling will help guide the siting of monitoring wells and enable operators to optimize the number and position of wells. The Directorapproved testing and monitoring plan will describe the use and instal lation of monitoring wells at the site.

EPA acknowledges the commenters' concern about th e cost of pressure monitoring. However, EPA b elieves that this monitoring is essential for protection of USDWs at GS sites Although a significant cost in absolute terms, monitoring costs are expected to be a small fracti on of site operating costs, according to EPA's cost analysis for the GS rulema king (which is available in the docket).

Other EPA Comment Codes and Descriptions: 4670 2.6.7 Surface air monitoring and/or soil gas monitoring (seeking comment) Comment: §146.90 Testing and monitoring re quirements. (71) "At the Director's discretion, surface air monitoring and/or soil gas m onitoring to detect movement of carbon dioxide that could endanger a USDW. "

We recommend deletion of this requireme nt in its entirety. While this requirement may be suitable for determin ing potential air leak age relevant to monitoring of CO2 in a greenhouse gas polic y context, this requirement does not
p rovide any additional protection to migr ation to USDW as surface breakthrough will only occur well after the deep-surf ace migration of CO2 to a USDW. Surface monitoring to detect CO2 has high uncertain ty and seasonal vari ability that is likely to result in many false positives and operational distractions. Seismic methods of tracking the CO2 pl ume are more effective than soil gas monitoring of CO2, which is affected by many other factors and thus is highly variable.

Response: EPA acknowledges that surface air and soil gas measurements ar e subject to variability and may not be suitable in all settings as a method to ensure USDW protectio n. However, EPA does not believe that this should entirely preclude their use. The decision to use surface monitoring and the selection of monitorin g methods will be site-specific (e. g ., ma y be influenced b y g eolo gy , in j ection Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technologies Council (GTC) Comment ID: 23776depth, and operational conditions) and must be based on potential risks to USDWs within the AoR. The Agency believes that surface air and soil gas m onitoring, when coupled with subsurface monitoring, may be appropriate at some GS projects to ensure USDW protection.

The final rule at §146.90(h) retains the allowance for surface air and soil gas m onitoring at the discretion of the Director as a means of identifying leaks th at may pose a risk to USDWs and informing emergency notification of a Class VI owner or operator and UIC Director in the event of a USDW endangerment,
p ursuant to requirements at §146.91(c). EPA clarifies th at the decision to use su rface monitoring and the selection of monitoring methods wi ll be site-specific (e.g., may be influenced by geology, injection depth, and operational conditions) and must be based on potential risks to USDWs within the AoR.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: Section 146.87 (e), Logging, Sampling, and Testing Prior to Injection Well Operation, FR page 43538

It is stated that, "Upon completion, but prior to operation, the owner or operator must conduct the following tests to veri fy hydrogeologic characteristics of the injection zone:

(1) A pump test; or

(2) Injectivity tests."

A`pump' test can be either injecting or withdrawing fluid. The following suggested rewrite reduces redundancy: "Upon completion, but prior to operation, the owner or operator must conduct pum ping tests to verify the hydraulic
p roperties of the injection zone. Thes e tests can take the form of :

(1) withdrawal tests; or

(2) injectivity tests."

Response: EPA retained the requirements in the final ru le as proposed because existing UIC program requirements use similar language and the tests and their purposes are understood by the regulated community. Additionally, the Agency believes that verification of hydrogeologi c characterization will generate the same information as the suggested alternative language.

Other EPA Comment Codes and Descriptions: 5700 2.12 Comments on the proposed duration of Class VI permits (seeking comment) Comment: Rule Provision: 144.36(a)

API Comments: (a) Permits for Class I and V wells shall be effective for a fixed term not to exceed 10 years. UIC Pe rmits for Class II AND III and VI wells shall be issue d EFFECTIVE for a period up to the operatin g life of the Commenter Name: James Devine Letter ID: 0166 Commenter Or g anization: United States Geolo g ical Surve y (USGS) Comment ID: 21350

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24136facility. PERMITS FOR CLASS VI WELLS SHA LL BE EFFECTIVE FOR THE PERIOD THROUGH

SITE CLOSURE.

Rationale: Permits are necessary for Clas s VI wells through the end of the post closure monitoring phase, which is consistent with the term site closure in the amended requirement.

Response: EPA clarifies that the final GS rule specifies that Class VI permits wi ll be issued for the operating life of the facility and the post-injection site care period (144.36(a)). The rule also adds a requirement that the Director review each Class VI permit at least ever y five years to determine whether it should be modified, revoked and reissued, terminat ed, or a minor modificati on made as provided in §§144.39, 144.40, or 144.41. The Director’s review will be informed by the owners’ or operators’ iterative reevaluation of the project . Specifically, the final rule includes a requirement that the AoR be reevaluated at least every five year s, and also requires owners or opera tors to review and update the AoR and corrective action plan, the testing and monitoring plan, and the emergency and remedial response
p lan throughout the life of the project (146.84(e), 146.90(j), and 146.94(d)). Owners or operators must review each plan and identify necessary amendments or demonstrate to the Di rector that no amendment is needed. In no case can reviews occur less often than once every five years. The iterative process and subsequent plan reevaluations ensure that time and resources are committed to the most critical aspects of the permit in preventing endangerment to USDWs.

Other EPA Comment Codes and Descriptions: 2064 1.5.3.2 Grandfathering construction of Class II wells (seeking comment) Comment: Rule Provision: 146.25 GEOLOGIC SEQUESTR ATION IN OIL OR GAS RESERVOIRS WITHOUT ENHANCED RECOVERY OF OIL OR NATURAL GAS

API Comments: WELLS USED FOR GEOLOG IC SEQUESTRATION AND MEETING THE CLASSIFICATION CRITERIA OF SECTIO N 146.5(B)(5) SHALL BE SUBJECT TO THE FOLLOWING REQUIREMENTS: (A) EXISTING WELLS THAT M EET OR EXCEED THE CONSTRUCTION REQUIREMENTS OF § 146.22 SHALL BE SUBJECT TO PART 146, SUBPART H [A S REVISED BY API] EXCEPT SECTIONS 146.86 AND 146.87. (B) NEW WELLS MUST MET THE CONSTRUCTION REQUIREMENTS OF SECTION 146.22 AND ARE SUBJECT TO PART 146, SUBPART H [AS REVISE D BY API] EXCEPT SECTIONS 146.86 AND 146.87

Rationale: Details of what would be required of "Class IIB" wells are to be worked out during future discussions of the Multi-Stakeholder Discussion Group (MSDG). However, API offers this language which is consistent with changes API had suggested before discussions with the MSDG began (see Section 146.81(c)). These suggestions are - as noted - conti ngent on EPA‘s adoption of API‘s changes to Part 146, Subpart H. Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24139Response: As described above regarding the suggested edit at 144.6, EPA did not make the suggested change. The Agency disagrees that wells injectin g CO2 for the primary purpose of long-term storage should be regulated under Class II requirements becau se Class II requirements do not address the unique risks posed by GS while ensuring protection of USDWs from endangerment.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tran sitioning from Class II to Class VI.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: API Comments: (b) This subpart applies to wells used to inject carbon dioxide EXCLUSIVELY for the purpose of geologic sequestration, i.e., the long-term containment of a gaseous, liquid or supercritical carbon dioxide stream in subsurface geologic formations. IT IS RECO GNIZED THAT SOME ACTI VITIES CONDUCTED UNDER CLASS II, INCLUDING CO2 BASED EO R OR EGR MAY SEQUESTER A PORTION OF THE CARBON DIOXIDE STREAM USED FOR EOR OR EGR. THIS SUBPART DOES NOT APPLY TO INJECTION OF A CARBON DIOXIDE STREAM FOR PURPOSES OF EOR OR EGR EVEN THOUGH GEOLOGIC SEQUESTRATION OF CARBON DIOXIDE MAY OCCUR DURING OR IN CONNECTION WITH EOR OR EGR OPERATIONS AND/OR ACTIVITIES.

Rationale: See 144.6. Deleted "gaseous, liqui d or supercritical" because it was added to the definition of CO2 stream.

Response: As described above regarding the suggested edit at 144.6, EPA did not make the suggested change. The Agency disagrees that wells injectin g CO2 for the primary purpose of long-term storage should be regulated under Class II requirements.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tran sitioning from Class II to Class VI.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Rule Provision: 146.81(c)

API Comments: (c) This subpart applies to owners and operators of permit or rule-authorized Class I industrial, Class II , or Class V experimental carbon dioxide injection projects who seek to apply for a Class VI geologic sequestration permit for their well or wells. If the Director determines that USDWs will not be endangered, such we lls are exempt, at the Director‘s discretion, from the casin g and cementin g requirements at §§ 146.86(b) and Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24140

Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24141146.87(a)(1) through (3).

Rationale: The reference to Class II wells in section 146.81(c) is no longer needed due to addition of 146.25 . However, if EPA were not to adopt section 146.25, API would suggest the following revisions:

(c) This subpart applies to owners and operators of permit or rule-authorized Class I industrial, Cl ass II WHO HAVE CEASED AND WILL NO LONGER CONTINUE EOR OR EGR OPERATIONS OR ACTIVITIES, or Class V experimental carbon dioxide injection
p rojects who seek to apply for a Class VI geologic sequestration permit for their well or wells. If the Director determines th at USDWs will not be endangered, such wells are exempt, at the Director‘s discretion, from the casing and cementing requirements at §§ 146.86(b) and 146.87(a)(1) through (3). CLASS VI REQUIREMENTS. CLASS II W ELLS PERMITTED FOR CO2 INJECTION AND THAT HAVE DEMONSTRATED MIT ARE EX EMPT FROM THE REQUIREMENTS AT §§146.86 AND 146.87.

The language allows for the transition of Class II wells to Class VI operations. These wells should be allowed to inject CO2 for storage based on their history of sound performance under the Class II progr am as demonstrated by MIT results. The language also allows the Director to exercise discretion to exempt other Class VI requirements.

Response: As described above, EPA disagrees that wells injecting CO2 for the primary purpose of longterm storage should be regulated under Class II requirements.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tran sitioning from Class II to Class VI.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(b)

API Comments: (b) A surface map showing th e PROPOSED LOCATIONS FOR the injection well(s) for which a permit is sought and the applicable area of review. Within the area of review, the map must show th e number, or name and location of all KNOWN injection wells, producing wells, abandoned wells, plugged wells or dry holes, deep STRATAGRAPHIC boreholes, Stat e or EPA approved subsurface cleanup sites, surface bodies of water, springs , mines (surface and subsurface), quarries, water wells and other pertinent surface features including structures intended for human occupancy and roads. The map should also show faults, if known or suspected. Only information of public record is required to be included on this map;

Rationale: Faults are not shown on maps unl ess there is a surface expression of Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24151the fault. Also, faults are detailed in (d) below and this language appears redundant.

The word "known" needs to be added to re move any implication that an applicant has to conduct studies to determine the lo cation of wells that are not currently documented in some fashion.

Response: EPA did not delete “faults” from §146.82(b) b ecause faults may have surface expressions that should be presented on submit ted maps to complement the requi red cross section data. EPA is developing guidance on site characteri zation for GS projects to assist owners or operators and Directors in evaluating permit requirements and applicati ons under §146.82. The guidance provides recommendations regarding charac terizing the regional geology and hydr ogeology of a proposed GS site as well as performing the necessary geochemical, geomechanical, and geophys ical analyses of the injection and confining zone. The guida nce can be found on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Please see the final rule and the discussion of geologic site characteriza tion in the preamble for additional information.

EPA acknowledges that some smaller fractures may not be detectable during the site characterization
p rocess, and clarifies that §146.82(a)(3 )(ii) requires the owner or opera tor to submit data on known or suspected faults and fr actures (i.e., not all fractures). Other re quirements for GS inje ction wells and sites can mitigate the potential impacts of unidentified fractures. These include li mitations on injection
p ressures to avoid propagation of existing fractures in the confini ng zone (§146.88(a)), collection and assessments of CO2 monitoring data at the site, and Ao R reevaluations (§146.84(e)) to assess possible CO2 movement through high-perm eability regions (i.e., faul ts and/or fractures) not detected in the initial site characterization.

EPA believes that a determination about whether or what information may be necessary (for a specific GS project) is outside of the public record and will be site-specific and based on knowledge of the site, data availability, and data quality . For instance, in meeting the requi rement to tabulate information on wells in the AoR, the Director has the discretion to require the owner or opera tor to supplement a data records search if there is reason to believe that the incompletene ss of available information could compromise USDW protection from endangerment.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(c)

API Comments: (c) A MAP DELINEATIN G the area of review based on UPON modeling, using ALL AVAILABLE data INCL UDING DATA obtained during logging and testing of the well and the formation as required by paragraphs (l), (r), and (s) of this section ANY WELLS IN THE AREA OF REVIEW

Rationale: This appears to be related to a condition where a well is already drilled. This does not align with reques ting information to receive a permit.

Response: EPA a g rees that not all of the informat ion listed at §146.82 of the proposed re g ulation will be Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24152available at the time the owner or operator develops their initial permit a pplication. In response to comments and based on an evaluation of the proposed requirements at §146.82, the Agency revised this subpart so that the final regulation specifies separate requirements for information to be submitted with the permit application and before well construc tion is approved (at §146.82(a)) and information to be submitted before operation of the well is authorized (at §146.82(c)).

The requirement to provide the fi nal area of review based on modeli ng and data obtained during logging and testing is in the final GS rule at §146.82(c)(1). Please see the final rule and the discussion of geologic site characterization in the preamble for additional information.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(d)(1) and (2)

API Comments: (d) KNOWN informati on on the geologic structure and hydrogeologic RESERVOIR properties of the proposed storage site and overlying formations, including:

(1) ISOPACH maps and OF THE PROPOSED INJECTION AND CONFINING ZONE(S), A STRUCTURAL CONTOUR MAP HUNG ON THE TOP OF THE PROPOSED INJECTION ZONE, AND AT LEAST TWO GEOLOGIC cross sect ions of the area of review SHOWING THE GEOLOGIC FORMATIONS FROM THE SURFACE TO TOTAL DEPTH.

(2) Location, orientation, and prope rties of known or suspected SUBSURFACE faults and fractures that may transect the confining zone(s) in the area of review and a determinati on that they would not interfere with containment;

Rationale: If the information is not known, it cannot be reported. "Reservoir" and changes to (1) and (2) are technical corrections.

Fractures generally can’t be identified until a well is drilled and evaluated. Even then, only fractures in the immediate vicinity of the wellbore can be identified.

This responsibility is best left with EPA.

Rule Provision: 146.82(d)(3)

API Comments: (3) Information on seismic hist ory THAT HAVE AFFECTED THE PROPOSED AREA OF REVIEW, INCLUDING KNOWLEDGE OF PREVIOUS SEISMIC EVENTS, including the

p resence and depth of seismic sources a nd a determination that the seismicity would not interfere with containment;

Rationale: Information on seismic histor y should have some de g ree of relevance Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24153to the project. This responsibility is best left with EPA.

Rule Provision: 146.82(d)(4)

API Comments: (4) Data on the depth, areal extent, thickness, mineralogy,
p orosity, permeabil ity and capillary RESERVOIR pressure of the injection and confining zone(s) WITHIN THE AREA OF REVIEW; including geologic/facies changes based on field data which may include geologic core s, outcrop data, seismic surveys, well logs, and na mes and lithologic descriptions;

Rationale: Deleted capi llary pressure because it is too hard to measure outside of the lab. Using sidewall cores, it ma y be difficult to determine capillary
p ressure. Additionally, full cores are not available until after the well being
p ermitted is drilled.

Rule Provision: 146.82(d)(5)

API Comments: (5) KNOWN geomechanical information on fractures, stress, ductility, rock strength, and in situ fluid pressures within the confining zone(s) WITHIN THE AREA OF REVIEW; and

Rationale not provided

Response: EPA acknowledges that some sm aller fractures may not be detectable during the site characterization process, and clarifies that §146.82(a)(3)(ii) requi res the owner or operator to submit data on known or suspected faults and fractures (i.e ., not all fractures). Ot her requirements for GS injection wells and sites can mitigate the potential impacts of unidentified fractures. These include limitations on injection pr essures to avoid propagation of existi ng fractures in the confining zone (§146.88(a)), collection and assessments of CO2 monitoring data at the site, and Ao R reevaluations (§146.84(e)) to assess possible CO 2 movement through high-permeability regions (i.e., faults and/or fractures) not detected in the initial site characterization. Regarding the requirement to determine capillary pressure, EPA recognizes that this informati on may not be available until after a well has been drilled. EPA revised §146.82 so that the final regulati on specifies separate requirements for information to be submitted with the permit application and before well cons truction is approved (at §146.82(a)) and information to be submitted before operation of the well is authori zed (at §146.82(c)). Final information on injection zone pressures would be required following drilling of the well, at §146.82(c)(4).

EPA disagrees that information submitted with Class VI permit applications should be limited to known (i.e., previously available) data. Site-specific conditions may affect the suitability of a proposed site. Therefore the owner or operator must provide to the Director the necessary pr eliminary information to support a permit decision.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(e)

API Comments: (e) A tabulation RECORD of all wells ARTIFICIAL PENETRATIONS within the area of review which penetrate THAT REACH the Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24154injection or confining zone(s). Such data AS AVAILABLE IN THE PUBLIC RECORD must include a description of each well ’ s PENETRATION’S type, construction, date drilled, location, depth, record of pl ugging and/ or completion, and any additional information the Director may require;

Rationale: Artificial penetrations is a more inclusive term.

Rule Provision: 146.82(f)

API Comments: (f) Maps and stratigraphi c cross sections indicating the general vertical and lateral limits of all USDW s, water wells and springs within the area of review, their positions relati ve to the injection zone(s) and the direction of water movement, where known; POTENTIOMETRIC (WAT ER LEVEL) SURFACE MAP(S) OF EXISTING AQUIFERS BEING UT ILIZED AS PRIVATE OR PUBLIC WATER SUPPLIES AND THE DIRECTION OF GROUNDWATER FLOW IN THESE AQUIFERS WITHIN THE AREA OF REVIEW. AT LEAST TWO GEOLOGIC CROSS SECTIONS SHOWING THE THICKNESS AND GENERAL VERTICAL AND LATERAL LIMITS OF ALL USDWS WITHIN THE AREA OF REVIEW.

N o rationale provided

Rule Provision: 146.82(g)

API Comments: (g) Baseline geochemi cal data on subsurface formations, including all USDWs in the area of review COMPILATION OF AVAILABLE GEOCHEMICAL DATA ON THE PROPOSED INJECTION ZONE AND NEAREST POROUS AND PERMEABLE FORMATION ABOVE THE CONFINING ZONE.

Rationale: Limits the data to be submitte d to available information and to the injection zone and the zone immediately above the confining zone which are the zones most likely to be monito red for potential CO2 leakage.

Response: As described above, EPA disagrees that the information that is submitted to support a Class VI permit application should be limited to known/available data.

EPA believes that a thorough unde rstanding of the hydrogeologic conditi ons of all USDWs in the AoR is necessary, and disagr ees with the suggested edits because the GS rule, as written, a ffords flexibility to owners or operators and Directors to tailor the site characterization process to the unique features of the site. EPA encourages owners or operators and Di rectors to collaborate and consult during site characterization to discuss information needs and ensure that all appropriate data to assess the suitability of the site are collected. The Dire ctor has the authority to request additional hydrogeologic data or other data on USDWs as well.

The Agency believes that the requirement at §146.82( a)(6) to submit baseli ne geochemical data on subsurface geologic formations, including all USDWs in the AoR, is appropriate and protective of USDWs. EPA believes that this data will support monitoring plan development, inform injectate fate and transport model development (e.g., by providing appropriate input parameters), and provide information needed to respond to any unexpected a nd unpermitted leaks outside of the injection zone.The baseline geochemical informat ion will allow the owner or opera tor and permitting authority to evaluate monitoring data and identify any changes in subsurface geochemistry that may indicate fluid
movement.

The rule requires geochemical analysis of, at a minimum, the injection zone, confining zone, and all USDWs (§146.82(a)(6)). These geochemical tests are necessary to ensure the adequacy of the confining system and to serve as a baseline for future m onitoring. The Director has the discretion to require geochemical analysis of additional subsurface zones if, in the Dir ector's opinion, they are necessary for the protection of USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82); 4710 2.7.1 Propos ed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(h)

API Comments: (h) Proposed operating da ta: (1) Average and maximum daily INJECTION rate and volume of the carbon di oxide stream; (2) Average and maximum SURFACE injection pressure;

Rationale: Technical clarifications.

Rule Provision: 146.82(k)

API Comments: (k) Proposed stimulation program and a determination that stimulation will not inte rfere with containment;

Rationale: This responsibility is best left with EPA.

Rule Provision: 146.82(n)

API Comments: (n) A WELLBORE schematic or other appropriate drawings of the surface and of the subsurface constr uction details of the well AND SURFACE WELLHEAD CONSTRUCTION.

Rationale: Technical clarification.

Rule Provision: 146.82(q)

API Comments: q) The ANY status of corrective act ion on wells in the area of review;

Rationale: Clarifies that wells not need ing corrective action will not have a corrective action status.

Response: EPA acknowledges the commente r’s support for parts of the requirements under 146.82. EPA disagrees with suggested tec hnical clarifications re garding proposed operating data, needs for the stimulation program, and the status of corrective action. EPA adds th at it is developing guidance for owners or operators on the geologic site characteri zation, AoR, and corrective action processes. These
g uidances will provide re commendations and clarif y the intent of all requir ed elements of a permit Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24155application. The guidances can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3110 2.1.1 Proposed siting requirements (i.e., injection/confining zones, trapping mechanism) Comment: Rule Provision: 146.83(a)(2)

API Comments: (2) A confining zone(s) that is LATERALLY CONTINUOUS AND free of KNOWN TRANSECTING, transmis sive faults or fractures and of sufficient areal extent and integrity to contain the inj ected carbon dioxide st ream and displaced formation fluids and allow injection at proposed maximum pressures and volumes without initiating or propagating fractur es in the confining zone(s); and OVER AN AREA SUFFICIENT TO PREVENT THE MO VEMENT OF INJECTED OR DISPLACED FLUIDS INTO A USDW;

Rationale: The proposed clarification k eeps the emphasis on the non-endangerment of USDWs and limits the requirements to that which is known or can be readily determined.

Response: The Agency believes that the requirement at §146.83(a)(2) that the confining zone be free of transmissive faults or fractures as written is appropriate for Cl ass VI wells and is necessary to ensure containment of the injectate, and that requiring the confining zone to be free of transmissive faults maximizes protection of USDWs from endangerment. Class I hazardous waste injection well operators must also meet a similar requirement that the site is free of transmissive faults or fractures; they have successfully made such demonstrat ions in the past. EPA adds that the Director must evaluate all geologic data on the site to ensure protection of USDWs from endange rment before approving a site for a GS project.

Other EPA Comment Codes and Descriptions: 3120 2.1.2 Need to identify additional confining and containment zones (seeking comment) Comment: Rule Provision: 146.83(b)

API Comments: (b) At the Director ‘ s discretion, owners or operators of Class VI wells must identify and characteri ze additional zones that will impede vertical fluid movement, ar e free of faults and fract ures that may interfere with containment, allow for pressure dissipation, and provide additional opportunities for monitoring, mi tigation and remediation.

Rationale: This paragraph creates a presumption that additional confining zones WILL be required. It is also redunda nt given the previous sections.

Response: EPA clarifies that secondary confining zones are not require d for all GS sites. Rather, secondary confining zones are required when the Director determines that these zones are needed to maximize the protection of USDWs from endan g erment. EPA retains the requirement to identif y Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24156

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24157additional containment/confining zones, if required by the Director, as proposed (e.g., §146.83(b)). EPA believes that, in some situations, the presence of additional confining and c ontainment zones above the
p rimary (i.e., lowermost) confining zone can improve USDW pr otection. These laye rs could further impede vertical fluid movement a nd allow for pressure dissipation, and also provide additional sites for monitoring, mitigation, and remediation. The Agency beli eves that providing the Director discretion will allow consideration of a range of sites for GS, based on site-specific conditions, and ensure USDW
p rotection. EPA believes that requiring appropriate si te characterization by the owner or operator (under §146.82) and providing an appropriate degree of flexibility to the Director to evaluate site-specific geologic data will afford the greatest protection of USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(a)

API Comments: (a) The area of review is the region surrounding the geologic sequestration project that may be impact ed by the injection activity. The area of review is based on computational modeling that accounts for the physical and chemical properties of all phases of the injected carbon dioxide stream. THE SUBSURFACE THREE-DIMENS IONAL EXTENT OF THE CA RBON DIOXIDE PLUME, ASSOCIATED PRESSURE FRONT, AS WELL AS THE OV ERLYING FORMATIONS AND SURFACE AREA ABOVE THAT DELINEATED REGION.

Rationale: Edits make this provision consis tent with the definition of "Area of Review", which was revised.

Response: EPA disagrees that the AoR definition needs to specifically include th e overlying formations and surface area above the delineated region. The intent of the Ao R, a long-standing concept within the UIC Program, is to delineate the surface area and all subsurface formations below it that may potentially be impacted by injection activity. A cceptable delineation models will provide predictions of CO2 fate and transport, as well as changes in formation pressu re, in three dimensions as a function of time that can be used to delineate the subsurface storage site and the AoR. Although EPA disagrees with the commenter's suggested change, the Agency has carefully considered all comments on the AoR definition at 146.84(a) and modified it to read as follow s: The region surrounding th e geologic sequestration
p roject where USDWs may be endangered by the injection activity. The area of review is delineated using computational modeling that accounts for the physical and chemical properties of all phases of the injected CO2 stream and is based on available site characterization, monitoring, and operational data. EPA believes that this definition is sufficiently br oad and describes both the intent of the computational modeling and the relationship of the AoR to areas that are subject to the risks as sociated with injection.

Other EPA Comment Codes and Descriptions: 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(b) Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24158

Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24159API Comments: (b) The owner or operator of a Class VI well must prepare, maintain, and comply with a plan to deli neate the area of review for a proposed geologic sequestration project, periodically reevaluate the delineation, and
p erform corrective action that meets th e requirements of th is section and is IN A MANNER AND AT A FREQUENCY acceptabl e to the Director. As a part of the
p ermit application, for approval by the Director the owner or operator must submit an area of review and corrective action plan th at includes the following information:

Rationale: Clarification.

Response: EPA disagrees with the suggested change, a nd is retaining the approach of setting a minimum fixed frequency for reevaluating the AoR but has, based on commenters' input, changed the frequency from ten years to at least every five years, as specif ied in §146.84(e). EPA agrees with commenters that site-specific information is an im portant factor in deter mining an appropriate AoR reevaluation frequency, and adds that the owner or operator's AoR and corrective action plan must describe the minimum fixed frequency for reeval uating the AoR and the site-specific conditions on which this frequency is based. EPA adds that the Dire ctor will evaluate the proposed plan in connection with a review of a vast amount of geologic and proposed operating da ta in determining whether to approve the plan. EPA is developing guidance describing recommended approaches to preparing all of the required GS project plans, whic h will address considerations fo r determining an appropriate AoR reevaluation schedule. The guidance will be available on EPA's web site at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment); 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(b)(2)

API Comments: (2) A description of: (i) The minimum fixed frequency, not to exceed 10 years, the owner or operator
p roposes to reevaluate the area of review; (ii) The monitoring and operational conditions that would warrant a reevaluation of the area of review prior to the next scheduled reevaluation as determined by the minimum fixed frequency established in paragraph (b)(2)(i) of this section. (iii) (I) How monitoring and operational data (e.g., injection rate and
p ressure) will be used to inform an area of review re evaluation; and

N o rationale provided

Rule Provision: 146.84(b)(2)

API Comments: (iv II) How corrective action will be conducted to meet the requirements of paragraph (d) of this section, including what corrective action will be performed prior to injection a nd what, if any, portions of the area of review will have corrective action addressed on a phased basis and how the
p hasing will be determined; how corrective action will be adjusted if there are chan g es in the area of review; a nd how site access will be g uarantee d Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24160ARRANGED for future corrective action.

Rationale: Future access cannot be guaranteed for an area in advance that may not even be within the boundaries of the AOR/ project.

Response: EPA disagrees with the suggested changes. Regarding reevaluation of the AoR, EPA believes that periodic AoR reevaluation at a set frequency of at least every five years is necessary to ensure protection of USDWs from endangerment and address the uncerta inties inherent in predictive modeling. Periodic AoR reevaluations at §146.84(e) ensure that a deliberate effort is made to verify, based on monitoring and operational data, that the CO2 plume is moving within the subsurface as
p redicted. EPA believes that less frequent reevaluations may not be su fficient to appropriately model
p lume and pressure front movement , establish conditions for corrective action, and ensure protection of USDWs from endangerment.

EPA clarifies that if site monitoring data agrees with the existing AoR delineation, a model recalibration may not be necessary, and the AoR reevaluation may consist of a demonstration that the current AoR delineation is adequate base d on site monitoring data.

To the comment on site access, EPA clarifies that the purpose of the corrective action requirement at §146.84(d) is to ensure that all wells in the AoR that have the potential to cause the movement of CO2 or other fluids into or between USDWs receive appropriate corrective action. In general, to meet this requirement, the owner or operator will most likely need to obtain the right of access to wells that may require corrective action, and demonstrate they have done this in their proposed AoR and corrective action plan. The final rule retains the requirement as proposed.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(c)(1)

API Comments: (1) Predict, using comput ational modeling, the projected lateral and vertical migration of the carbon dioxide plume and formation fluids in the subsurface from the commencement of in jection activities until the plume movement ceases, pressure differentials sufficient to cause the movement of injected fluids or formation fluids in to a USDW are no longer present, or after FOR a fixed time period as dete rmined by the Director. The model MODELING must:

Rationale: Clarification.

Rule Provision: 146.84(c)(1)

API Comments: (i) Be based on detailed geologic data collected AVAILABLE to characterize the injection zone, conf ining zone and any additional zones ; and anticipated operating data, including in jection pressures, rates and total volumes over the proposed life of the geological sequestration project THE DURATION OF INJECTION; (i i) Take into account any RELEVANT geologic heterogeneities, AND da ta quality, and their possible impact on model
p redictions; and Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24161Rationale: Allows the use of all availa ble data, not just data collected specifically for this permit.

Response: EPA has clarified the language in §146.84(c)(1) fo r the final rule. It now reads, “Predict, using existing site characteriza tion, monitoring and operational data , and computational modeling, the
p rojected lateral and vertical mi gration of the carbon dioxide plum e and formation fluids in the subsurface from the commencement of injection activities until the plume move ment ceases, until
p ressure differentials sufficient to cause the movement of injected fl uids or formation fluids into a USDW are no longer present, or until the end of a fixed time period as determined by the Director.”

The final rule retains §146.84(c)(1)(ii) as proposed, exce pt that it now requires owners or operators to take into account other discontinui ties in addition to geologic hete rogeneities when determining the AoR.

EPA disagrees that only the injection and confini ng zones should be included in AoR modeling of GS sites. EPA believes that the modeling should also take into account the possibility of displaced fluids or brines caused by a lateral and/or ve rtical pressure plume, and theref ore it may be necessary to include additional zones along with the confin ing/injection zones to ensure the integrity of the confining zone and ultimately protect a USDW from endangerment.

Other EPA Comment Codes and Descriptions: 3420 2.2.2.1 Scope of the inventory process (e.g., reliance on publicly available in formation, depth of wells) Comment: Rule Provision: 146.84(c)(2)

API Comments: (2) Using methods approved by the Director, Identify all KNOWN ARTIFICIAL penetrations INTO THE CONFINING ZONE AVAILABLE IN THE PUBLIC RECORD, including active and abandone d wells and underground mines, in the area of review that may penetrate REACH the confining zone. Provide a description of each well‘s type, construction, date drilled, location, depth, record of
p lugging and/or completion, and any additi onal information the Director may require; and

Rationale: Changed for consistency with earlier language.

Response: EPA is retaining this requirement as proposed. EPA agrees with commenters that, for most GS sites, relying on database and ot her public records searches (i.e., of "known" artificial penetrations) will be sufficient to meet the requirements at §146.84(c)(2). However, the Agency recognizes that there may be situations where additional surveys or research to locate wells may be appropriate. For example, there may be cases where the Dire ctor may determine that ground or airborne surveys for wells are appropriate, e.g., if there is reason to believe, based on knowledge of the site or of available data, that the incompleteness of information on known well s could compromise USDW protection from endangerment. In order to preserve the Director's discretion to re quire an operator to supplement a records search, EPA did not make the suggested change.

EPA clarifies that any well that pe netrates the confining zone, even if it does not extend all the way throu g h the confinin g formation, is to be included in the tabulation. The g uidance describes EPA's Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24162recommended approaches for the data to be considered in an initial AoR delineation, how to apply computational modeli ng to delineate the AoR, performing corre ctive action at GS sites, and, when appropriate, completing AoR reevaluations. The guida nce will be available on EPA's web site at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: Rule Provision: 146.84(c)(3)

API Comments: (3) Determine which aba ndoned wells IDENTIFIED IN 146.84 (C) (2) in the area of review have been plugged (as required by §146.92) in a manner that prevents the movement of carbon dioxide or associated FORMATION fluids that may endanger USDWs.

Rationale: Remove as redundant.

Response: EPA clarifies that the term "associated fluids" as proposed in §146.84(c)(3) refers to formation fluids, other injectates, et c. that may be present in the subs urface and affect movement of the CO2 plume and/or pressure front. EPA believes this terminology woul d incorporate any fluids in the subsurface that could potentially move through artificial penetrations and affect USDWs. EPA has revised the language at §146.84(c)(3) to read, "... ca rbon dioxide or other fl uids that may endanger USDWs..." EPA disagrees that deleting the term area of review is necessary and has retained the term in the final rule language.

Other EPA Comment Codes and Descriptions: 3460 2.2.2.3 Acceptable correct ive action techniques for GS sites (e.g., cements) Comment: Rule Provision: 146.84(d)

API Comments: (d) Owners or operators of Class VI wells must perform corrective action USING MATERIALS SUITABLE FOR USE WITH THE CARBON DIOXIDE STREAM AND FORMATION FLUIDS, on all wells in the area of review IDENTIFIED IN 146.84(C) (2) that are determined to need correct ive action". using me thods necessary to
p revent the movement of fluid into or between USDWs including use of corrosion resistant materials, where appropriate.

Rationale: Experience with CO2 based EO R strongly supports the use of many conventional materials that might not meet the technical definition of "corrosion resistant".

Response: EPA revised the text at §146.84(d) to require the use of materials that are "compatible with the carbon dioxide stream." EPA beli eves this language change addresses commenters' concerns and is also consistent with other language regardi ng materials requirements in the GS rule. Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24163

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24164

Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24165Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: Rule Provision: 146.84(e)

API Comments: (e) If monitoring data i ndicate an endangerment to USDWs, the owner or operator must notify the Director and cease operations as required by § 146.94.

Rationale: This is not needed since §146.94 already specifies the notification and cessation of injection. API suggests the removal of this language as unnecessarily duplicative.

Response: Based on consideration of all public comments and other information, EPA deleted this
p rovision from §146.84. The final rule now contains a provision in §146.91(c) that requires the owner or operator to report within 24 hours any evidence that th e carbon dioxide stream or associated pressure front may cause an endangerment to a USDW. EPA believes this change consolidates reporting requirements in one place and provides additional clarity.

Other EPA Comment Codes and Descriptions: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) Comment: Rule Provision: 146.84(f)

API Comments: (f) At the minimum fixed frequency, not to exceed 10 years, as specified in the approved area of revi ew and corrective action plan, or W hen monitoring and operational conditions warr ant, owners or operators must:

Rationale: Rather than a fixed time period, API recommends following a
p erformance based approach that woul d be based on significant changes in injection parameters or anom alous monitoring results.

Response: EPA believes that periodic Ao R reevaluation at a set frequency is necessary to ensure
p rotection of USDWs from endangerment and address the uncertainties inherent in predictive modeling. Periodic AoR reevaluations at §146.84(e) ensure that a deliberate effort is made to verify, based on monitoring and operational data, that the CO2 plume is moving within the subsurface as predicted. EPA believes that less frequent reevaluations may not be sufficient to appropriately model plume and
p ressure front movement, establish conditions for corrective ac tion, and ensure pr otection of USDWs from endangerment.

EPA clarifies that if site monitoring data agrees with the existing AoR delineation, a model recalibration may not be necessary, and the AoR reevaluation may consist of a demonstration that the current AoR delineation is adequate base d on site monitoring data.

Based on the comments received (including thos e by water associations, an energy company, associations, industries, states, and environmental groups), EPA ha s changed the minimum frequency for the AoR reevaluation from ten years to at least ev ery five years. EPA beli eves that this revised frequency addresses commenters' concerns about the inherent uncerta inties in modeling CO2 movement, the emerging nature of GS technology, risk-based ta rgeting of monitoring activities, and the unique nature of CO2 GS. Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24166Other EPA Comment Codes and Descriptions: 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(f)(4)

API Comments: (4) Submit an amended area of review and corrective action plan or demonstrate to the Director through monito ring data and modeling results that no amendment CHANGE to the area of review and corrective action plan is needed.

Rationale: Clarification

Response: EPA disagrees with the suggested changes and be lieves the proposed text is clear as written. For additional information on EPA's approach to AoR and corrective action, please see the final rule and
p reamble.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Rule Provision: 146.85(a)(1)

API Comments: (1) The Director receives WELL PLUGGING REPORT IDENTIFIED IN 146.92(D) and approves OR COMPLETION OF the completed post-injection site care and site closure plan AS APPROPRIATE; and

Rationale: Maintenance of the well pl ugging financial obligation until site closure is not necessary. The Director s hould have the authority to release the obligation once the well is plugged.

Rule Provision: 146.85(b)

API Comments: (b) The owner or operator must provide to the Director, at a frequency determined by the Director, BUT NO MORE THAN ANNUALLY, written updates of adjustments to the cost estimate to account for any amendments CHANGE to the area of review and corrective ac tion plan (§146.84), the injection well
p lugging plan (§146.92), and the post-injection site care a nd site closure plan (§146.93).

Rationale: Updates more frequent than annual is not justified.

Rule Provision: 146.85(c)

API Comments: (c) The owner or operator must notify the Director of adverse financial conditions such as bankruptcy, that may affect the ability to carry out injection well plugging and post-injection site care and site closure.

Rationale: Clarification.

Response: Owners or operators have the flexibilit y to choose from a variet y of financial instruments to Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24167

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24168meet their financial responsibility obligations. Fo r example, owners or operators may use one or multiple financial responsibility instruments for well plugging and PISC (§146.85(a)(6)). However EPA will not allow for a separate fina ncial responsibility demonstration for well plugging and PISC (i.e., a demonstration submitted prior to well plugging and the beginning of th e post-injection site care period rather than with the permit applic ation). A demonstration of financial responsibility for all phases of the GS project will be required prior to the issu ance of a Class VI perm it (§146.85(a)(5)(i)).

To ensure that financial resources are available to protect USDWs from endange rment, the GS rule (at §146.85) identifies qualifying financial instruments, th e time frames over which financial responsibility must be maintained, procedures for estimating th e costs of activities covered by the financial instruments, procedures for notifying the Director of adverse financial conditions, and requirements for adjusting cost estimates to reflect changes to the project plans.

In addition, on an annual basis, the owner or operator mu st adjust the cost estimate for inflation, increase or decrease the value of the financial instrument to match the cost estimat e, and provide any updated information related to their fina ncial responsibility instrument(s), or at any othe r time deemed appropriate by the Director. These annual reviews provide a mechanism for revising cost estimates up or down to account for changes in the project, incl uding the execution of environmental obligations as
p hases of a GS project are completed.

Regarding the suggested edit at §146.85(a)(1), EPA clar ifies that the financial instrument the owner or operator provided to meet the requirements under §146.85 wi ll be released when the phase of the project for which the instrument was required is complete and all financial obligations for that instrument have been met, pursuant to §146.85(b)(2) and §146.93.

The GS rule, at §146.85(c), requires the owner or operator to have a detailed written estimate, in current dollars, of the cost of: performing corrective action on wells in the AoR, plugging the injection well(s), PISC and site closure, and emergency and remedial response. A cost estimate must be prepared separately for each of these activit ies and be based on the costs to the owner or operator of hiring a third
p arty (who is neither a parent nor a subsidiary of the owner or operator) to perform the activities. However, EPA is not requiring independent third-part y reviews of owner or operator cost estimates.

EPA is developing guidance on financial responsibility for GS wells. The guidance will include a discussion on how best to estimate costs to assist Cla ss VI well owners or opera tors, third party insurers or providers of financial instrume nts, and permitting auth orities in developing estimates of the costs associated with various GS activities. Th e guidance is available on EPA's website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

EPA did not make the proposed edits at §146.85(b) and (c), but did extensively revise and clarify the financial responsibility requirement s. See the final GS rule and preamble for additional information on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5432 2.9.1.1 Need to adjust financial responsibility mechanisms (seeking comment) Comment: Rule Provision: 146.85(d)

API Comments: (d) The operator must provide an adjustment of the cost estimate to the Director if the Director has reason to believe that ori g inal THE MOST Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24169RECENT demonstration is no longer adequate to cover the cost of injection well
p lugging (as required by §146.92) and post-injection site care and site closure (as required by §146.93)

Rationale: Clarification.

Response: EPA agrees that it is important to periodical ly update cost estimate s that support financial responsibility determinations. EP A clarifies that the GS rule, at §146.85(e), requires the owner or operator to provide annual updates to the cost estima te to account for any amendments to the AoR and corrective action plan, the injecti on well plugging plan, and the PISC an d site closure pl an. See the final rule and preamble for further discussion of EPA' s final approach to fi nancial responsibility.

Other EPA Comment Codes and Descriptions: 3800 2.3 Proposed Injection Well Construction Requirements ( 40 CFR 146.86) Comment: Rule Provision: 146.86(a)(1)

API Comments: (1) Prevent the movement of fluid into or between USDWs or into any unauthorized zones; CONTAINING ANY CONTAMINANT IN TO USDWS, IF THE PRESENCE OF THAT CONTAMINANT MAY CAUSE A VI OLATION OF ANY PRIMARY DRINKING WATER REGULATION UNDER 40 CFR PART 142 OR MAY OTHERWISE ADVERSELY AFFECT THE HEALTH OF PERSONS.;

Rationale: The proposed changes reflect the nonendangerment standard that is the basis of the UIC program.

Response: EPA disagrees that the proposed language provided in §146.86 does not reflect the nonendangerment standard as required under the SDWA. EPA believes that protection of USDWs from endangerment and prevention of flui d movement between formations is paramount and the language as
p roposed meets the non-endangerment st andard, therefore it is not necessary to make such edits. Appropriately designed and constructed wells are necessary to prevent endangerment to USDWs and maintain integrity of the well th roughout the lifetime of a GS project. This is the foundation of the requirements for construction and pre-operational testing of Class VI wells at §§146.86 and 146.87.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revi sions to the GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3860 2.3.3 Well component degradation Comment: Rule Provision: 146.86(b)(1)

API Comments: (1) Casing and cement or othe r materials used in the construction of each Class VI well must have sufficient structural strength and be designed for the operatin g life of the g eolo g ic sequestration pro j ect WELL. All well Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24170

Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24171materials must be compatible SUITABLE FOR USE with the fluids with which the materials may be expected to come into c ontact and meet or ex ceed TEST standards OR PRACTICES developed for such material s by the American Petroleum Institute, ASTM International, or comparable sta ndards acceptable to the Director. The casing and cementing program mu st be designed to prevent the movement of fluids into or between USDWs. In order to allo w the Director to determine and specify casing and cementing requirements, the owner or operator must provide the following information:

Rationale: The life of a geologic sequestra tion project could be different than the life of the well. Clas s VI well design should be based on the life of the well.

Response: EPA disagrees that the casing, cement, or ot her materials should only be designed for the
p eriod of the injection process rather than the life of the sequestration pr oject. GS projects are anticipated to have long life spans in comparison to other types of deep injection wells. Not only must Class VI wells be able to function sa fely and properly over the lifespan of the GS project, but they must b e constructed such that USDWs remain protecte d after well plugging. The requirements at §146.86 will ensure that the well can maintain integrity thr oughout the proposed life span of the project, including after the injection well is plugged and through the post-injection site care period and beyond. While the risk profile of a GS site will decrease following cessation of inje ction, EPA believes that Class VI wells must be designed to protect USDW s from endangerment for the life of the project. Furthermore, rigorous casing and cementing help ensure that the Class VI well will not serve as a conduit for movement of fluids associated wi th future injection operations.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements (seeking comment) Comment: Rule Provision: 146.86(b)(1)

API Comments: (v) Corrosiveness COMPOSITION of the car bon dioxide stream and formation fluids;

Rationale: There is no method for measur ement of "corrosive ness" of a CO2 stream. The relevant information is the composition of the CO2 stream.

Response: EPA clarifies that, although corrosiveness does not have a unit of measure, corrosiveness can be technically measured and desc ribed. Procedures that can identify corrosion (or the absence of corrosion) in a Class VI well provide valuable operational information that the Director needs to determine appropriate standards for the tubing and packer.

Other EPA Comment Codes and Descriptions: 3860 2.3.3 Well component degradation Comment: Rule Provision: 146.86(b)(1)

API Comments: (vi) Down-hole te mperatures AND PRESSURES; (viii) T y pe or g rade of cement AND ADDITIVES; and Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24172

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24173Rationale: Technical clarification.

Response: EPA agrees with the suggestion that §146.86(b)(1 )(viii) be revised to also address cement additives. In the final GS rule, the subparagraph read s as follows: "Type or gr ade of cement and cement additives."

EPA clarifies that information on down-hole pressures is required at §146.86(b)(1)(ii).

Other EPA Comment Codes and Descriptions: 3822 2.3.1.1 Depth of surface casing (seeking comment) Comment: Rule Provision: 146.86(b)(2)

API Comments: (2) Surface casing must extend through the base of the lowermost USDW ABOVE THE INJECTION ZONE and be cemented to the surface.

Rationale: In some parts of the US the USDW is very deep and this standard may
p reclude geologic sequestra tion in these areas.

Response: EPA disagrees with the suggested edit or that the surface casing requirements in the GS rule
p reclude injection below deep USDWs. The final GS rule at §146.86(b)(2) requires that surface casing extend through the base of the lowermost USDW and be cemented to the su rface through the use of single or multiple strings of cas ing and cement. It does not, however, specify how cementing must be accomplished, and gives flexibility to the owner or operator to propose alternate methods- to provide a sufficient amount of cement to meet the standard that USDWs are protected from endangerment. EPA notes that there are many potential ways to meet the requirement, such as the use of staged cementing.

EPA recognizes concerns re garding construction of Class VI well s where the lowermost USDW is very deep. To further address comments on deep inje ction wells, the final GS rule at §146.95 includes requirements for owners or operators that seek a waiv er of the injection depth requirements. Owners or operators of wells operating under in jection depth waivers must comp ly with additional construction requirements to ensure that wells used to inject above or between USDWs are protective. See the discussion of the waiver approach in the preamble to the final GS rule for additional information.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: Rule Provision: 146.86(b)(3)

API Comments: (3) At least one long st ring casing, using a sufficient number of centralizers SET IN A MANNER SO AS TO CREATE A CEMENT BOND THROUGH THE INJECTION AND CONFINING ZONE(S). THE LONG STRING CASING must extend to the injection zone and must be cemented ISOLATED by circulating cement to the surface in one or more stages. PLACING CEMENT AND/OR OTHER ISOLATION TECHNOLOGIES AS NECESSARY TO PROVIDE ADEQUATE ISOLATION OF THE INJECTION ZONE Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24174

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24175AND PROVIDE FOR PROTECTION OF USDWS.

Rationale: Cementing to surface is not necessary to protect USDWs, and may have negative consequences, as follows. Cement to surface would eliminate the ability to monitor pressures in th is annulus and would limit flexibility of remedial options. As revised, the propos al would allow for applicat ion and development of alternative technologies. See API RP90 for description of risk-based approach for managing situations involving annular casing pressure. Industry experience with CO2 EOR under the Class II program demonstrates the effectiveness of existing cementing procedures.

Rule Provision: 146.86(b)(4)

API Comments: (4) Circulation of cemen t may be accomplished by staging. The Director may approve an alternative method of cementing in cases where the cement cannot be recirculated to the su rface, provided the owner or operator can demonstrate by using logs that the ceme nt does not allow fluid movement behind the well bore.

Rationale: Same as above

Response: EPA disagrees with the suggested edits. EPA be lieves that the require ments for long-string casing are appropriate and offer appropriate flexibility: §146.86(b)(3) requires that the long-string casing extend to the injection zone and be cemented by circulating cement to the surface in one or more stages. It does not, however, specify how cementing would be accomplished, and gives fl exibility to the owner or operator to propose altern ate methods to provide a sufficient am ount of cement to meet the standard that USDWs are protected from endangerment, subject to the approva l of the Director.

EPA stresses that protection of US DWs is the primary mission and ma ndate of the UIC program and the
p urpose of all requirements for injection wells. A ny injection activity must be demonstrated to not endanger USDWs, regardless of their depth, and if such non-endangerment cannot be shown, then the activity will not be allowed under UIC requirements or the SDWA.

EPA disagrees that the requirement at §146.86(b)(4) should be deleted. Section 146.86(b)(4) of the final rule allows alternate methods of staging the cement, at the Director 's discretion, provided the owner or operator can demonstrate using logs that the cemen t does not allow fluid movement behind the wellbore.

EPA does not believe that the cementing require ments at §146.86 would prevent monitoring, operation, and remediation of Class VI wells. Cementing of deep wells has been performed successfully in the past by owners or operators of Class I hazardous and Class I municipal waste disposal wells. Some of these wells, which must meet the same cementing and ca sing requirements as Class VI wells, are up to 12,000 feet deep and have been successf ully cemented in a manner that main tains integrity and allows for all required well testing, op eration, and remediation (EPA, 2001). S ee the discussion of Class VI well construction requirements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://wat er.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24176(seeking comment) Comment: Rule Provision: 146.86(b)(5)

API Comments: (5) Cement and cement additives must be compatible SUITABLE FOR USE with the carbon dioxide stream and formation fluids and of sufficient quality and quantity to maintain integrity over the design OPERATING life of the geologic seque stration project WELL. The integrity and location of the cement shall be verified using technology capable of evaluating cement quality radially and identifying the location of ch annels to ensure that USDWs are not endangered.

Rationale: Experience with CO2 EOR under th e Class II program demonstrates the effectiveness of existing cementing materials and procedures. Standard API cements have been used in numerous CO2 EOR operations with no adverse consequences. Refer to the citations wi thin EPA‘s proposed rule 73 FR 43532- 43533: Carey et al., (2007), Crow et al., (2008), and Meyer, J.P (2007).

Response: EPA disagrees that the casing, cement, or ot her materials should only be designed for the
p eriod of the injection process rather than the life of the sequestration pr oject. GS projects are anticipated to have long life spans in comparison to other types of deep injection wells. Not only must Class VI wells be able to function sa fely and properly over the lifespan of the GS project, but they must b e constructed such that USDWs remain protecte d after well plugging. The requirements at §146.86 will ensure that the well can maintain integrity thr oughout the proposed life span of the project, including after the injection well is plugged and through the post-injection site care period and beyond. While the risk profile of a GS site will decrease following cessation of inje ction, EPA believes that Class VI wells must be designed to protect USDW s from endangerment for the life of the project. Furthermore, rigorous casing and cementing help ensure that the Class VI well will not serve as a conduit for movement of fluids associated with future injection operations.

EPA recognizes that the oil and gas industry has decades of expe rience injecting CO2 and has demonstrated the effectiveness of existing cementi ng materials and procedures. The final GS rule, at §146.86(b)(1), specifies that all casing and cementing or other materials used in the construction of Class VI wells must meet or excee d standards developed for such ma terials by the American Petroleum Institute, ASTM International, or comparable stan dards acceptable to the Director. This requirement invokes the expertise of these bodies to ensure that the requirements for construction of Class VI wells reflect the state of the art in well construction technology. Se e the discussion of Class VI well construction requirements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://wat er.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3826 2.3.1.3 Packer requirements (seeking comment) Comment: Rule Provision: 146.86(c)(2)

API Comments: (ii) COMPOSITION of the carbon dioxide stream. (chemical content, corrosiveness, temperature, and density);

Rationale: There is no method for measur ement of "corrosive ness" of a CO2 stream. The relevant information is the composition, not characteristics, of the Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24177CO2 stream. The composition of the CO2 stre am is more relevant to the design of a tubing and packer system.

Rule Provision: 146.86(c)(2)

API Comments: (iii) MAXIMUM PROPOSED Injection temperature and pressure; (iv) MAXIMUM PROPOSED Annular pressure; (v) MAXIMUM PROPOSED Injection rate (intermittent or conti nuous) and volume of the carbon dioxide stream;

Rationale: Technical corrections.

Response: As written, the text at §146.86(c)(3)(ii) accounts fo r all characteristics of the CO2 that could affect the performance of the tubing and packer , including the chemical content, corrosiveness, temperature, and density. The suggest ed revision to refer to CO2 "composition" would be less precise. EPA clarifies that, although corrosiveness does not have a unit of measure, corrosiveness can be technically measured and described. Procedures that can identify corro sion (or the absence of corrosion) in a Class VI well provide valu able operational information that the Director needs to determine appropriate standards for the tubing and packer.

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

EPA has revised §146.86(c)(3)(iii) and (iv) to refere nce the maximum proposed injection pressure and maximum proposed annular pressure, respectively. EPA has revised §146.86(c)(3)( v) to read "proposed injection rate (intermittent or c ontinuous), and volume and/or mass of the carbon dioxide stream." EPA believes that reference to the c ontinuous injection rate would be duplicative of the maximum rate. EPA believes that considering the maximum injection and annular pressure would be more protective.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)

API Comments: (a) During the drilling and construction of a Class VI injection well, the owner or operator must run appropriate logs, surveys and tests to determine or verify the depth, thickne ss, porosity, permeability, and lithology of, and the salinity of any formati on fluids in, all re levant geologic formations to assure EVALUATE conformance with the injection well construction requirements under §146.86, and to establish accurate baseline data against which future measurements may be compared. The owner or operator must submit to the Director a descriptive report prepar ed by a knowledgeable log analyst that includes an interpretation of the results of such logs and tests. At a minimum, such logs and tests must include: THE DIRECTOR MAY REQUIRE SUCH LOGS AND TESTS AS MAY BE NE EDED AFTER TAKING INTO ACCOUNT THE AVAILABILITY OF SIMILAR DATA IN THE AREA OF THE DRILLING SITE, THE CONSTRUCTION PLAN, Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24178AND THE N EED FOR ADDITIONAL INFORMATION THAT MA Y ARISE FROM TIME TO TIME AS THE CONSTRUCTION OF THE WELL PROGRE SSES AND THESE MAY INCLUDE THE FOLLOWING:

Rationale: Obtaining the geologic inform ation will not assure conformance with well construction requirements, just measure or evaluate it.

In well defined areas, these evalua tions are frequently unnecessary. The Director should have discre tion to select the appropriate requirements necessary to obtain sufficient baseli ne data and information. For example, in an area where a number of wells are being drille d, the logging of surface hole yields little useful addi tional information.

In particular, this change would allow the Director to reduce the requirements when multiple wells are installed for a project.

Response: EPA believes that all logs, surveys, and test s listed at §146.87(a) are necessary to verify information about the injection and c onfining zones and ensure that the well is being drilled and cased as approved, and has mechanical integrity. This informati on is needed to demonstrate that the well can be operated and tested in a manner that protects USDWs from endangerment. While the tests do provide information on some of the same it ems, each test provides unique piec es of information that build on each other and allow for interpretati ons not possible with a single test.

EPA notes that the Director has the discretion at §146.87(a)(5) to a pprove alternative methods that
p rovide equivalent or better information, and th e Director may accept information on cores of the injection and confining zones from nearby wells if the owner or ope rator can demonstrate that such cores are representative of conditi ons at the well in question and co re retrieval is not possible, as specified at §146.87(b). EPA believes that logs a nd tests must be performed on each well drilled regardless of existing information about the area to account for the co mplexity of CO2 injection well construction and the buoyancy of CO2. Existing lithologi c and geologic informati on may lack the details needed for site-specific well design and the geology needed to s upport protection of USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 4110 2.4.1.1 Injection pressure limitations Comment: Rule Provision: 146.88(a)

API Comments: (a) Except during stimulati on, the owner or operator must ensure that injection pressure does not exceed 90 percent of the fracture pressure of the injection zone so as to assure th at the injection does not initiate new fractures or propagate exis ting fractures in the injection zone. In no case may injection pressure initiate fractures in the confining zone(s) or cause the movement of injection or formation fluids that endangers a USDW. (A) THE OWNER OR OPERATOR MUST COMPLY WITH A MAXIMUM INJECTION PRESSURE LIMIT APPROVED BY THE DIRECTOR AND SPECIFIED IN THE PERMIT . IN APPROVING A MAXIMUM INJECTION PRESSURE LIMIT, THE DIRECTOR SHALL CONSIDER TH E RESULTS OF WELL TESTS AND, WHERE Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24180APPROPRIATE, GEOMECHANICAL OR OTHER STUDIES THAT ASSESS THE RISKS OF TENSILE FAILURE AND SHEAR FAILURE. THE DIRECTOR SHALL APPROVE LIMI TS THAT, WITH A REASONABLE DEGREE OF CERTAINTY, WILL AV OID INITIATION OR PROPAGATION OF FRACTURES IN THE CONFINING ZONE OR CAUSE OTHERWISE NON-TRANSMISSIVE FAULTS TRANSECTING THE CONFINING ZONE TO BE COME TRANSMISSIVE. IN NO CASE MAY INJECTION PRESSURE CAUSE MOVEMENT OF INJECTIO N OR FORMATION FLUIDS IN A MANNER PROHIBITED BY 40 CFR PART 144.12(A)

Rationale: API is concerned about three aspects of proposed section 146.88(a), governing injection pressure limitations. Fi rst, it "restricts" fractures in the injection zone "except during stimulation" rather than focusing on maintaining the integrity of the confining zone, which is what really matte rs for protecting USDWs. Second, it fails to refer specifical ly to the full ra nge of potential geomechanical failure mode s potentially posed by opera tions at a particular site. Third, the type of geomechanical ri sk that is addressed (initiation or
p ropagation of fractures), is dealt with in a potentially arbitrary fashion (the 90% of fracture pressure limit), which may not be appropriate in all cases.

The MSDG‘s recommended language addr esses these concerns by focusing on maintaining the integrity of the confin ing zone and including tensile failure and shear failure as transmissivity concerns. It calls for additional geomechanical studies of tensile fail ure and shear failure only "where appropriate" because there will be lo cations where experience or existing information will provide sufficient eviden ce to avoid the need for additional studies. The need for conducting additiona l tests and for determining which tests would be acceptable is left to the Director‘s discretion.

Response: EPA notes that because determination of the in jection pressure limit is based on the fracture
p ressure of the injection zone, the limit is site-specific and not arbitrary. EPA em phasizes that injection
p ressure limits are important to prot ect against fracturing of the confining zone, and that the requirement at §146.88(a) that the pressure in the injection zone not exceed 90 percent of the fracture pressure
p rovides a margin of safety in the well operation and protects US DWs from endange rment. If the Director determines, based on a review of the information collected as pa rt of site characterization, that a lower injection pressure limitation is appropriate in order to prevent endangerment of USDWs, the Director has the authority to set a lower limit in th e operating permit than the limit established in the rule.

EPA notes that during the site charac terization process, owners or opera tors must submit data about the geology of the site, as specified at §146.82(a), including data on known or suspected faults and fractures and geomechanical information on frac tures, stress, ductility, rock strength, and in situ fluid pressures within the confining zone. The Director will use these data to determine appropriate limits on injection.

In response to the concern about reopening of faults at lower pressures than 90 percent of fracture
p ressure, EPA believes that the requirement for th e owner or operator to submit data on known or suspected faults and fractures and information on the seismic history of the site will inform the determination of an appropriate pr essure limitation in the permit. Any sites with the potential for reopening or reactivation of faults or unacceptable seismic risk that could otherwise interfere withcontainment will not be permitted as GS sites.

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators in meeting the requirements of §146.82 a nd to assist Directors in evaluating permit applications. The guidance will describe recommended approach es for characterizing the regional geology and hydrogeology of a proposed site and performing th e necessary geochemical, geomechanical, and geophysical analyses of the inject ion and confining zone. EPA is al so developing guidance for primacy agencies that will include recommended approaches for evaluating owner or operator-submitted data in setting permit conditions. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4100 2.4.1 Injection parameters Comment: Rule Provision: 146.88(b)

API Comments: Injection OF THE CO2 STREAM be tween the outermost cas ing protecting USDWSs and the well bore is prohibited.

Rationale: Routine injection into zones other than th e target interval(s) should be prohibited; however, wording of this requirement is not clear as to which interval is being addressed. An absolute prohibition on injection into this annulus may also limit diagnostic options that could be useful.

Response: EPA retains the provision as propos ed, and clarifies that injection between the casing and the well bore is prohibited. This is consistent with requirements for other injection well classes.

Other EPA Comment Codes and Descriptions: 4100 2.4.1 Injection parameters Comment: Rule Provision: 146.88(c)

API Comments: (c) The owner or operator mu st fill the annulus between the tubing and the long string casing with a non-corr osive fluid approved by the Director. The owner or operator must maintain on th e annulus a pressure that exceeds the operating injection pressure, unless th e Director determines that such requirement might harm th e integrity of the well. A POSITIVE PRESSURE ON THE ANNULUS.

Rationale: Industry experience with the Class II UIC program does not support this requirement.

Positive annular pressure that exceeds the operating injection pressure is not necessary because a leak from tubing to annulus does not have the same implications as in a Clas s I hazardous situation.

Response: EPA believes that maintaining an annulus pressure that is highe r than the injection pressure, as required at §146.88(c), will ensure that if there are leaks in the tubing, the annulus fluid will move into the tubing, rather than the inj ectate moving out of the tubing and potentially along the outside of the well. EPA believes this requirement is appropriate fo r Class VI wells g iven the potential hi g h volumes Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24181

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24182and supercritical nature of the CO2 injectate, poten tial geomechanical stresses in the wellbore, and the
p otential for movement of the CO2 in the event of a mechanical integrity loss.

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: Rule Provision: 146.88(e)

API Comments: (e) The owner or operato r must install and use continuous recording devices to monitor: the injection pressure; the rate, volume, and temperature of the car bon dioxide stream and. THE OWNER OR OPERATOR MUST REGULARLY MONITOR th e pressure on the annulus betw een the tubing and the long string casing and annulus fluid volume and. THE OWNER OR OPERATOR must install and use alarms and automatic down

- hole shut-off systems, designed to alert the operator and shutin the well when operating parameters such as injection rate, injection pressure, or othe r parameters approved by the Director diverge beyond ranges and/or gradie nts specified in the permit;

Rationale: Over-pressure protecti on is best achieved by ensuring compatibility of the casing/tubing materi al design strength with the surface injection (compression) syst em. Down-hole shut-in devi ces are not appropriate for this application. These devises are installed in the tubing string and are typically near the surface of the well. They‘re intended to seal the tubing in the event of catastrophic failure of the wellhead. These devises would provide little if any protect ion to USDWs. Is not practicable to install these devises deep within the well (e.g. shortly above the packer). Additionally these devises create a restriction on runni ng other tools like logging tools in the well and therefore could limit an operators ability to do required monitoring and diagnostic work. Lastly, these devises re quire periodic testing and maintenance which could require either pulling the device by wireline or by pulling the entire tubing string depending on the type of device installed. Either of these activities would be disruptive and costly to the overall project operations.

A more appropriate approach would be installation of landing nipples at appropriate points in the tubing string which would allow use of wireline retrievable plugs when needed.

Response: EPA acknowledges that proper de sign of the well, including appropriate materials and emplacement of casing and tubing, is essential to proper operation of Class VI wells. Such design, however, does not eliminate the possi bility of failure, e.g., due to over-pressurization as suggested by the commenter. EPA believes that a multiple-barrier approach, which includes appropriate well design as required at §146.86, suitable injection pressure limits as required at §146.88(a), and automatic shut-off systems, as required at §146.88(e), is necessary to ensure protection of USDWs from endangerment from the risks associated with CO2 GS.

Landing nipples, which are machined portions of the tubing that allow the seating of components–such as safety valves—at a later time, can be used to de ploy safety valves after the initial well completion. EPA believes, however, that if the shut-off system is not deployed until the failure occurs, CO2 will be free to flow out of the well until the shut-off valve is deplo y ed. Since installin g the new shut-off s y stem Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24183will require getting the device to the site, setting up a rig, and de ploying the device down the well, a significant amount of time could elapse following an adverse even t before the well is sealed. EPA believes that the risks of uncontrolled CO2 flow are too great to be allowed for such a length of time.

As described above, EPA will not require automati c down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells install automatic surface shut-off devices. The rule afford s Director's discretion to mandate automatic downhole shut-off devices in onshore situations that ma y warrant their use. The rule requires, at §146.88(e) (3), that owners or operators of offshore wells within State territor ial waters install automatic down-hole shut-off systems. EPA believes that these require ments at §146.88(e) ensure that proper precautions are taken to prevent subsurface fluid moveme nt and ensure protection of USDWs.

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: Rule Provision: 146.88(f)

API Comments: (f) If aN down

- hole automatic shutdown is triggered or a loss of mechanical integrity is discovered, th e owner or operator must immediately investigate and identify as expeditiously as possible the cause of the shutoff. If, upon such investigation, the well appears to be lacking mechanical integrity, or if monitoring required under paragraph (e) of this section otherwise indicates that the well may be lacking mechanical integrity, the owner or operator must:

Rationale: Technical clarifi cation given changes above.

Response: As described above, EPA will not require au tomatic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells install automatic surface shut-off devices. The rule affords Director's discretion to mandate automatic down-hole shut-off devices in onshore situations that may warrant their use. The rule requires, at §146.88(e)(3), that owners or operators of offshore well s within State territorial waters install automatic down-hole shut-off systems. Please see the final rule and preamble fo r additional information on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4000 2.4 Proposed Injection Well Operating Requirements ( 40 CFR 146.88) Comment: Rule Provision: 146.88(f)(3)

API Comments: (3) Notify the Direct or within 24 hours OF DISCOVERY;

N o rationale provided

Response: The final rule text at §146.88(f) now reads, "I f a shutdown (i.e., down-hole or at the surface) Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24184

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24185is triggered or a loss of mechanical integrity is discovered." Therefore the notice required at §146.88(f) (3) must be provided within 24 hours of an automati c shut-off device being triggered or a loss of mechanical integrity being discovered. EPA believes this provision is necessary to ensure timely response to potential USDW endangerment.

Other EPA Comment Codes and Descriptions: 4520 2.5.1 Continuous internal mechanical integrity monitoring (seeking comment); 4720 2.7.2 Oper ational recordkeeping and reporting Comment: Rule Provision: 146.89(b)

API Comments: (b) To evaluate the abse nce of significant leaks under paragraph (a)(1) of this section, owne rs or operators must, following an initial annulus
p ressure test, continuously monitor AND RECO RD AT LEAST DAILY, ANNULUS PRESSURE AND VOLUMES OF PACKER FLUID INJECTED OR REMOVED FROM injection pressure, rate, injected volumes, and pressure on the annulus between THE tubing and long
stem STRING casing and annulus fluid volume as specified in §146.88 (e);

Rationale: Technical clarification.

Response: EPA agrees with the commenter regarding the importance of dem onstrating internal mechanical integrity (MI), but disagrees with the s uggested changes. Class VI injection wells must be equipped with dedicated computer-based continuous pressure monitoring devices in concert with the shut-off systems required for GS wells, which typically take readings several times per second (i.e., more frequently than daily) and record them electronically in a computer system. See §146.88. For additional information, please see the discussion of MITs in the final rule preamble.

EPA also disagrees that it is necessary to report volumes of packer fluid injected or removed. EPA agrees with the commenter that recording annulus fluid volume may not be appropriate. EPA believes that knowing annulus fluid volume (146.88(e)) is a necessary componen t of monitoring well mechanical integrity, but believes that knowing th e annulus fluid volume added is suff icient to meet the intent of the requirement. The final GS rule requires that owners or operators use continuous recording devices to monitor injection pressure, rate, and volume, as well as the pressure on the annulus between the tubing and the long string casing. It also modifies the requirement in the proposed rule to continuously monitor annulus fluid volume; it now requires recordi ng of annulus fluid volume added. See §§146.88(e); 146.89 (b); and 146.90 (b).

The final rule includes the suggested change from “long-stem” to “long-string” casing.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: Rule Provision: 146.90(b)

API Comments: (b) Installation and use, ex cept during well workovers as defined in §146.86 8(d), of continuous recording MONITORING devices (INCLUDING DIGITAL DEVICES CAPTURING PERIODIC DATA) to monito r injection pressure, rate and volume; AND RECORD AT LEAST DAILY the pressu re on the annulus between the tubin g and the Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24186

Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24188long string casing; and the annulus fluid volume;

Rationale: §146.86(d) does not exist; perhaps §146.88(d) is what was apparently intended.

There is concern regarding what cons titutes continuous monitoring. Industry agrees that regular monitoring of th e parameters identified by EPA is appropriate. Our experience with CO2 EOR strongly shows that da ily monitoring of most of these parameters is adequate (e xceptions to this would be on a sitespecific basis). Recording should generally be done on a daily basis and reporting on a semi-annually basis.

Response: EPA believes that a monitoring regime that include s continuous pressure monitoring of GS wells, as required at §146.88(e), is important and appropriate because the potentially corrosive nature of CO2 streams in the presence of water makes it criti cal to immediately identify corrosion-related well mechanical integrity loss.

Regarding the question of what constitutes continuous monitoring, EPA expects th at Class VI injection wells under §146.88(e) will be equipped with dedicated computer- b ased continuous pressure monitoring devices (in concert with the Dir ector-approved shut-off systems require d for GS wells), which typically take readings several times per se cond and record them electronically in a computer system. EPA did not specify the types of devices in the final rule, however.

EPA adds that the final GS rule refere nces §146.88(e), as the commenter suggests.

Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: Rule Provision: 146.90(c)

API Comments: (c) WHERE CONDITIONS WARRANT, corrosion monitoring of the well materials for loss of mass, thickness, cracking, pitting and other signs of corrosion must be performed on a AND RECORDED AT LEAST quarterly basis WHICH MAY BE MODIFIED TO BE LESS FR EQUENT AS APPROVED BY THE DIRECTOR BASED ON CONSTRUCTION MATERIALS, OPERATING COND ITIONS, AND MONITORING HISTORY to

ensure that the well components m eet the minimum standards for material strength and
p erformance set fort h in §146.86(b) by:

Rationale: Technical correction. API questions the need for corrosion moni toring of most inje cted CO2 streams since they will typically be nearly pure and dry thus having no corrosive
p roperties. Industry experience with pr oduction, transportation, and injection of dry CO2 strongly illustrates the non-corrosive nature of this type of CO2
stream.

Response: EPA believes that corrosion m onitoring is warranted and necess ary for all Class VI wells in order to protect USDWs. CO2 in the presence of water (including wate r with NOx, SOx, and H2S impurities) can be corrosive to well materials and cements. Thus, althou g h a CO2 stream ma y be dr y , Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24189the potential for corrosion of well materials down-hole, where the in jectate can potentially mix with water in the target formation, must be considered.

Several laboratory studies and a limi ted number of field studies have i nvestigated and characterized the effects of carbonic acid on well materials. Laborat ory studies (e.g., Kutchko et al., 2007; Kutchko et al., 2008) consistently identify alterations (typically car bonation) of cement as the result of interactions between cement and CO2-saturated brine.

Currently, there are only a few analys es of cement from wells that have been in prolonged contact with CO2 in actual field (down-hole) c onditions. Evaluation of cement from a well at the Scurry Area Canyon Reef Operators Committee (SACROC) site show ed alteration, but did not show degradation that compromised the structural integrity of the ceme nt (Carey et al., 2007). In another study, cement samples were collected and analyzed from a CO 2 production well in a natural CO2 reservoir in Colorado exposed to a CO2-water down-hole envir onment for 30 years (Crow et al., 2008). The study found evidence of reaction between th e CO2-rich water and the cement.

Oil industry research also addresses the effects of corrosion of steel tubing and pipes. Lopez et al. (2003) noted that 60 percent of oilfield failures are related to the effects of carbonic acid from produced brines on carbon and low alloy steels.

Laboratory investigation of cement alteration/degradation is an ongoi ng research area. Few field-based studies have been completed to date. The laboratory and field studies currently available suggest that corrosion problems can be managed; however, there is not a large e nough body of research to rule out
p otential corrosion problems of st eel components of injection well s. The IPCC (2005) report on carbon dioxide capture and storage reviewed oil and gas i ndustry experience with gas injection wells, close industry analogues to CO2 injection wells. The report st ated that while the design of CO2 injection wells will be very similar to gas injection wells, most down-hole components of the CO2 injection wells will “need to be upgraded for higher pressure ratings and corrosion resistance.” Given the pressure and corrosion considerations, anticipated long lifespan of a GS well, and the difficulties that would be associated with a corrosion-relate d well failure, EPA believes thatcorrosion monitoring in the downhole environment is justified. For these reasons, the fi nal rule requires quarterly corrosion monitoring (at §146.90(c)).

Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: Rule Provision: 146.90(c)

API Comments: (1) Placing ANALYZING coupons of the well construction materials PLACED in contact with the carbon dioxide stream; or (2) Routing the carbon dioxi de stream through a loop constructed with the material used in the well AND INSPECT ING THE MATERIALS IN THE LOOP; or (3) Using an alternative method, MATERIAL S, OR TIME PERIOD approved by the Director;

Rationale: Clarifying edits.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA ha s made many revisions to the GS rule. See the final rule and
p reamble for further discussion on EPA's final approach. Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24190Other EPA Comment Codes and Descriptions: 4660 2.6.6 Geochemical monitoring Comment: Rule Provision: 149.90(d)

API Comments: (d) Periodic m onitoring of the ground water FORMATION FLUID quality and geochemical changes above IN A PERMEABLE AND POROUS FORMATION AS N EAR AS PRACTICABLE TO the confining zone (s) FOR GEOCHEMICAL CHANGES that may be a result of carbon dioxide OR DISPLACE D FORMATION FLUID movement through the confining zone or additional identified zones: (1) The location and number of monitoring wells must be based on specific information about the geol ogic sequestration project, including injection rate and volume, geology, the presence of artifi cial penetrations and other RELEVANT factors AS WARRANTED BY A RISK-ASSESSMENT; (2) The monitoring frequency and spatial distribution of monitoring wells must be based on GEOLOGICAL, geoche mical AND GEOPHYSICAL data that has been collected under § 146.82(a)(6) §146.82(D) and any modeling re sults in the area of review evaluation required by §146.84(b);

Rationale: Drilling monitoring wells should be carefully considered since each well introduces a potential pathway for m ovement. In addition the cost of adding multiple wells could create a barrier to CCS development, while providing limited information on actual m ovement of the CO2 stream.

Response: EPA agrees that monitoring plans and methods need to be site-specific and believes that the monitoring requirements for GS sites at §146.90 provide an appropriate level of fl exibility in structuring a testing and monitoring plan that protects USDW s from endangerment, while addressing the needs suggested in the commenter’s proposed edits.

Regarding monitoring locations, section §146.90(d) requires periodic monitoring of the ground water quality and geochemical changes above the confini ng zone(s). EPA clarifie s that this monitoring requirement does not include the confining layer it self. Monitoring above the confining layer will
p rovide an indication of upward movement of CO2 that might endanger a USDW. The exact number of formations to be tested must, however, be based on site-specific characteristics and vulnerabilities and described in the Director-approve d testing and monitoring plan.

To mitigate the risk of fluid movement, EPA requires owners and operators to submit a testing and monitoring plan that describes how the owner or operator plans to site and construct monitoring wells.

EPA believes, however, that monitoring using wells in the injection zone, e.g., for pressure monitoring as required at §146.90(g)(1), can be safely performe d if the wells are constructed to prevent flow between the injection zone and US DWs or other layers above the c onfining zone. Such construction technologies exist and have been used in the oil a nd gas industry for years. EPA believes that properly constructed monitoring wells will be a safe way to obtain the data that is essential to ensure that the injected CO2 remains confined in the injection zone and that pressure changes are not causing movement or formation of other fl uids. To mitigate the risk of fl uid movement, EPA requires owners and operators to submit a testing and monitoring plan that describes how the owner or operator plans to site and construct monitoring wells. EPA is developing guidance on well construction that will include recommendations for monitorin g well construction. The g uidance will be available on EPA’s website at Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24191http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

EPA is developing guidance on testing and monitoring to assist owners or opera tors and Directors in evaluating requirements under §146.90, in cluding proposed monitoring pl ans. The guidance describes available technologies and recommended approaches for implementing a test ing and monitoring plan, including pre-operational geophys ical logging and test ing of injection wells, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

EPA acknowledges the commenters' conc ern about the cost of monitoring. However, EPA believes that monitoring is essential for protecti on of USDWs at GS sites. Although a significant cost in absolute terms, monitoring costs are expected to be a small fraction of site operating costs, according to EPA's cost analysis for the GS rulemaking (w hich is available in the docket).

Other EPA Comment Codes and Descriptions: 4540 2.5.2 Proposed external MIT requirements; 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: Rule Provision: 146.89(c)

API Comments: (c) At least once per year, the owner or operator must confirm the absence of significant fluid movement under paragraph (a)(2) of this section USING A METHOD ACCEPTABLE TO THE DI RECTOR (E.G. INCLUDING DIAGNOSTIC SURVEYS SUCH AS OXYGEN-ACTIVAT ION LOGGING OR TEMPERATURE OR NOISE LOGS). (1) A tracer survey such as oxygen

- activation logging; (2) A temperature or noise log; or (3) A casing inspection log, if required by the Director.

Rationale: Revised text supports a perfor mance-based approach and allows the development and use of new technologies as they become available. Cement circulation to the surface is not necessary because having the open annulus above the top of cement allows regular monitoring of annular pressure which could indicate leakage.

Subsection (3) was deleted because it requires the tubing to be pulled at significant cost and risk of uncontrolled releases.

Response: EPA believes that the MITs described in §146.89( c) of the rule (e.g., an approved tracer log or temperature or noise logs) are effective methods to demonstrate external MI, provide an important early warning of potential problems in the injection well system, and represent standard techniques that have been used successfully by the drilling industr y and for the UIC Program for decades. The Agency notes that the regulations do provi de the Director the flexibility at §146.89(e) to approve the use of alternative MIT methods.

EPA a g rees that the casin g inspection lo g is not an appropriate test to detect fluid movement behind the Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24192casing, but clarifies that it is appropr iate to be used to determine the presence or absence of corrosion of the long-string casing, and is required if the Director determines that it is necessary based on sitespecific information. EPA has revised the final GS rule to require that the frequency of the casing inspection log must be specified in the appr oved testing and monitoring plan. See §146.89(d).

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: Rule Provision: 149.90(e) - (f)

API Comments: (e) A demonstration of exte rnal mechanical integrity pursuant to §146.89(c) at least once per year UNTIL THE WELL IS PLUGGED; (f) IF CONDITIONS WARRANT, A pressure fa ll-off test OR OTHER EQUIVALENT TEST THAT IDENTIFIES RESERVOIR CONDITIONS WI TH RESPECT TO FLOW DYNAMICS at least

once every five years unless more frequent te sting is required by the Director based on site specific information;

Rationale: Technical clarifications.

Response: Regarding pressure testing, EPA believes that pr essure fall-off testing is necessary for GS wells. Pressure fall-off test s are designed to verify that modeled pr ojections of reservoir pressure decline agree with measured pressure decline profiles. These tests can be useful in AoR calculations and reevaluations and may also indicat e mischaracterization of site geology and the presence of leakage
p athways. Therefore, EPA is requiring that pressure fall-off testing be conducte d every five years at a minimum, and the final GS regulat ion includes this requirement at §146.90(f). Pressure fall-off tests may be conducted in conjunction with other well perfor mance tests (i.e., mechanical integrity testing) to ensure safe and effective operations. EPA disagrees that the rule should provide specifics of the test at the degree suggested, however.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisi ons to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4650 2.6.5 CO2 plume and pressure front tracking (seeking comment) Comment: Rule Provision: 149.90(g)

API Comments: (g) Testing and monitoring AS APPROPRIATE TO SUPPORT THE MODEL FOR
to trackING the extent of the carbon di oxide plume and the position of the
p ressure front. by either monitoring fo r pressure changes in the first formation overlying the confining zone or using indirect, geophysical techniques (e.g., seismic, electrical, gravity, or electromagnetic surveys and/or down

- hole carbon dioxide detection tools);

Rationale: Monitorin g outside of the in j ection zone provides little information Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24193

Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24194of value for tracking and monitoring the inj ected plume. Examples of how to test and monitor could be included in the Preamble but need not be included in the rule itself.

Response: EPA has revised this requirement in the fina l rule. The final GS regulation, at §146.90(g)(1), requires all GS project owners or operators to moni tor for pressure changes in the injection zone. EPA believes that pressure monitoring in the injecti on zone is necessary to track the development and movement of the pressure front and CO2 plume.

Pressure monitoring within the injection zone is necessary because any such monitoring above the confining zone would not detect movement of the pr essure front unless a breach of the confining zone occurs. EPA believes that monitoring using wells in th e injection zone (i.e., that penetrate the confining zone) can be safely performed if the wells are constructed to prevent flow between the injection zone and USDWs or other layers above the confining z one. Such construction technologies exist and have been used in the oil and gas indus try for years. EPA believes that the benefits of monitoring in the injection formation outweigh the mana geable risk of those monitoring we lls serving as conduits for fluid movement. EPA adds that owners or operators may consider perfor ming additional pressure monitoring in wells that are above th e confining zone (e.g., in the same well s used to perform ground water quality monitoring required at §146.90(d)) to provide additi onal verification that no pressure changes are occurring above the confining zone due to CO2 leakage. Monitoring al so identifies needed remedial actions, provides inputs for AoR r eevaluation modeling, and targets a dditional geochemical and surface monitoring needs. Knowledge of the location of the CO2 plume and the associated pressure front will assure the public that GS projects are proceeding accord ing to plan, provide sufficient information to the owner or operator and Director, or allow for appropriate actions to address any indication that USDWs may be endangered.

EPA acknowledges that, at ce rtain sites, there may be a need for more or different monitoring schemes (which may include monitoring in the confining zone), and adds that it is important to balance the need for adequate monitoring that ensures USDW protec tion from endangerment agai nst too many artificial
p enetrations which could serve as conduits for flui d migration. EPA expects site-specific testing and monitoring plans to describe the proposed monitoring regime, which mu st be approved by the Director. Flexibility is also provided regarding how to monito r for the specific data required by the final rule. The testing and monitoring plan is developed by the owner or operator in consultati on with the Director and is designed to ensure that a detailed, Director -approved document describing how monitoring will be conducted during the lifetime of the project exists.

EPA is developing guidance on testing and monitoring to assist owners or opera tors and Directors in evaluating requirements under §146.90, in cluding proposed monitoring pl ans. The guidance describes available technologies and recommended approaches for implementing a test ing and monitoring plan, including pre-operational geophys ical logging and test ing of injection wells, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4670 2.6.7 Surface air monitoring and/or soil gas monitoring (seeking comment) Comment: Rule Provision: 146.90(h) Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24195API Comments: (h) At the Director’s disc retion BASED ON SITE-SPE CIFIC CONDITIONS AND RISK-BASED FACTORS, surface air moni toring and/or soil gas monitoring to detect movement of carbon dioxide that could endanger a USDW.

Rationale: In most situations soil a nd air monitoring does not provide an effective method of protecting USDWs.

Response: EPA clarifies that subsurface geochemical and pressure m onitoring in the subsurface formations are the first line of monitoring that would allow detect ion of potential endangerment to USDWs from GS activities (this is required at all GS sites, as desc ribed at §146.90(d)). The Agency also believes that surface air and soil gas monitoring, when coupled with subsurface monitoring, may be appropriate at some GS project s to ensure USDW protection.

The final rule at §146.90(h) retains the allowance for surface air and soil gas m onitoring at the discretion of the Director as a means of identifying leaks th at may pose a risk to USDWs and informing emergency notification of a Class VI owner or operator and UIC Director in the event of a USDW endangerment,
p ursuant to requirements at §146.91(c).

The selection of monitoring methods will be site-specific (e.g., may be influenced by geology, injection depth, and operational conditions) and must be based on potential risks to USDWs within the AoR.

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Rule Provision: 146.90(h)(1)

API Comments: (1) The testing and monitoring plan must be based on potential vulnerabilities SITE-SPECIFIC GEOLOGIC FACTORS, MODELING, AND RI SK-ASSESSMENT within the area of review;

Rationale: Technical clarification

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA ha s made many revisions to the GS rule. See the final rule and
p reamble for further discussion on EPA's final approach. EPA anticipates that the testing and monitoring
p lan will address site-specific ge ologic factors, modeling, and risk -assessment. EPA is developing guidance on how best to develop the various required project plans, including th e testing and monitoring
p lan. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Rule Provision: 146.90(i)

API Comments: (i) An y additional monitorin g , as required b y the Director, BASED Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24196

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24197ON SITE-SPECIFIC C ONDITIONS AND RIS K -BASED FACTORS, necessary to support, upgrade, and improve computational modeli ng of the area of review evaluation required under § 146.84(b) and to determin e compliance with standards under 40 CFR 144.12

Rationale: Technical clarification

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA ha s made many revisions to the GS rule. See the final rule and
p reamble for further discussion on EPA's final approach. EPA agrees that any additional monitoring requirements would be based on site -specific geologic factors, mode ling, and risk-assessment. EPA is developing guidance for directors that provides recommended approaches when exercising discretion to require additional monitoring. The guida nce can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4720 2.7.2 Operational recor dkeeping and reporting Comment: Rule Provision: 146.91(a)

API Comments: (a) Semi-annual OR LESS FREQUENT AT THE DISCRETION OF THE DIRECTOR

reports containing: (1) Any SIGNIFICANT change s to the physical, chemical and other relevant characteristics of the carbon dioxide stream from the proposed operating data;

Rationale: Over the life of the project, the Director may de cide that less reporting is acceptable

(1) Technical clarificati on. Significance can be deter mined by a statistical analysis of the data. Rules should recognize that there will be minor variations in many data se ts over time.

Rule Provision: 146.91(a)

API Comments: (3) A description of any SI GNIFICANT event that exceeds operating
p arameters for annulus pressu re or injection pressure as specified in the
p ermit; (4) A description of any SIGNIFICANT ev ent which triggers a shutdown device required pursuant to §146.88(e) and the response taken;

Rationale: EPA should consider some significance threshold on reporting these events to avoid reporting events that would be of limite d interest or
consequence.

Response: EPA disagrees that less frequent than semi-annual reporting is appropriate to protect USDWs from endangerment. The Agency believes semi-annua l reporting is appropriate and necessary for Class VI wells during the operational phase of the project. EPA believes that the potentially large injection volumes and injection pressures associated with GS warrant more frequent reporting than for other well classes. See the final ru le and preamble for further discussi on on EPA's final approach to testin g and Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24198monitoring.

EPA also retained the provision at §146.91(a)(3) as proposed. The final rule at §146.91(a)(3) requires reporting of all exceedances of operating parameters. EPA disagrees with the suggestion to report only "significant" exceedances. Making a determination as to whether an ex ceedance is "significant" is not the purpose of the requirement. EPA believes that the ability of an operator to consistently meet operating requirements and avoid exceedances provides evidence of a well-managed GS project that is in compliance with the Class VI permit. If multiple exceedances occur, the Dire ctor should be aware of such occurrences, determine whethe r these indicate problems at the si te, and determine the appropriate course of action (e.g., a well wo rkover, modification of operating parameters, or imposition of a
p enalty).

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(a)

API Comments: (a) Prior to the well plu gging, the owner or operator must flush each Class VI injection well with a buffer fluid, determine bottomhole reservoir
p ressure, and perform a final EXTERNAL mechan ical integrity test OF ANY RELEVANT WELLBORE MATERIALS REMAINING.

Rationale: Many of the components that woul d be tested by an internal MIT are removed or tested during the plugging process.

Response: EPA agrees that only an external MIT is re quired, and has modified the GS rule at §146.92 (a) to require owners or operators to perform a final external mechanical integrity test prior to the well
p lugging.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(b)(2)

API Comments: (2) Appropria te testing methods to ensure FINAL EXTERNAL mechanical integrity as specified in §146.89(C);

Rationale: Many of the components that woul d be tested by an internal MIT are removed or tested during the plugging process.

Response: EPA agrees that only an external MIT is re quired, and has modified the GS rule at §146.92 (a) to require owners or operators to perform a final external mechanical integrity test prior to the well
p lugging. Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24199

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24200

Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24201Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(b)(5)

API Comments: (5) The type and grade and quantity of material to be used in
p lugging. The material must be SUITABLE FO R USE with the car bon dioxide stream; and

N o rationale provided

Response: EPA believes, considering the pote ntially corrosive nature of CO2 when it is in contact with water, that the requirement that the material must be compatible with the CO2 stream is appropriate. The final rule retains this requirement.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(d)

API Comments: (d) Plugging report. Within 60 days after plugging the owner or operator must submit a plugging re port to the Director. If the semi

- annual report is due less than 15 days afte r completion of plugging, then the report must be submitted within 60 days after plugging. The report must be certified as accurate by the owner or operato r and by the person who performed the
p lugging operation (if other than the owner or operator.)

Rationale: The proposed changes are suggested to simplify and clarify a
p rovision that API believes is needlessly complicated.

Response: EPA has revised the text at §146.92(d) to reduce c onfusion. The final rule text reads, "Within 60 days after plugging, the owner or operator must submit a pluggi ng report to the Director."

Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities Comment: Rule Provision: 146.93(a)(1)

API Comments: (1) The owner or operato r must submit the postinjection site care and site closure plan as a part of the permit appl ication to be approved by the Director. SHALL CONTINUE TO CONDUCT MONI TORING AS SPECIFIED IN THE DIRECTOR-APPROVED POST-I NJECTION SITE CARE AND SITE CLOSURE PLAN, PURSUANT TO THE PERFORMANCE BASED CRITERIA DESCRIBED IN 146.93(B)(3).

Rationale: Revisions here reflect changes to §146.93(b)(3)

Response: EPA disa g rees with the su gg ested chan g es, and disa g rees that the post-in j ection monitorin g Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24202

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24203p eriod should be stri ctly performance- b ased. The Agency agrees that ther e will be limited circumstances where it can be demonstrated in less than 50 year s that the plume and pressure front no longer pose a risk of endangerment to USDWs, and has included re quirements in the final Class VI rule at §146.93(c) for an owner or operator to substantially demonstr ate that an alternative time frame ensures the
p rotection of USDWs. However, EPA anticipates that a default timefr ame for post-injection site care will necessary for most GS sites to ensure the protection of USDWs. A 50-year post-injection site care timeframe represents a r easonable and protective monitoring peri od based on a review of research studies, industry reports, and existi ng environmental programs, and ev aluation of public comments. For this reason, the final GS regulation includes a provision that the Director may, at his or her discretion, shorten the post-injection site care timeframe if the owner or operator can demonstrate that the GS
p roject does not pose an endangerment to USDWs, as specified in §146.93(b)(2). Such a demonstration will be site-specific, and based on pressure monitoring and USDW impacts.

The GS rule requires owners or operat ors to submit a post-injection site care and site closur e plan as part of the permit application, as specified in §146.82(a), in order to outline how these activities will be
p erformed and how non-endangerment of USDWs will be demonstrat ed throughout the post-injection site care period.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.93(a)(2)

API Comments: (2) The post

- injection site care and si te closure plan must include the following information: (i) The pressure differential betw een preinjection and predicted post

- injection
p ressures in the injection zone; (ii) The predicted position of the carbon dioxide plume and a ssociated pressure front at site closure as demonstrated in the area of review evaluation required under § 146.84(b); (iii) A description of post

- injection monitoring loca tion, methods, and proposed frequency; and (iv) A proposed schedule for submitting post

- injection site care monitoring results to the Director.

Rationale: Revisions here reflect changes to §146.93(b)(3)

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5200 2.8.2 Post injecti on site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.93(a)(4)

API Comments: (4) AT ANY TI ME DURING THE POST-INJECTION SITE CARE PHASE, The Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24204

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24205owner or operator may modify and resubmit the post-injection site care and site closure plan for the Director‘s approva l within 30 days of such change.

Rationale: Technical Clarification.

Response: EPA agrees that a post-injection site care monitoring plan is an important tool for GS, and anticipates that, in some cases, the appropriate post-injection monitoring strategy may end up being different than initially pr ojected, and there may be a need to ame nd the post-injection site care and site closure plan. EPA is requiring that upon the cessation of injection, th e owner or operator submit an amended post-injection site care and site closure plan or demonstr ate to the Director that no changes to the original post-injection site care and site closure plan are necessary (§146.93(a)(3)). EPA is not requiring formal periodic review and updates to the PI SC and site closure plan throughout the injection
p hase. EPA does not expect that changes to this plan would be implemented until injection operations cease. EPA envisions that owners or operators would take into account similar considerations that guide updates to other project plans, e.g., monitoring and operational data and results of AoR reevaluations. EPA adds that, if any mon itoring or other site data indicate a need for amendi ng the post-injection site care plan, the owner or operator is exp ected to amend the plan accordingly.

EPA adds that, in the final rule, it has revised th e text at §146.93(a)(4) as foll ows: "At any time during the life of the geologic sequestration project, the owner or opera tor may modify and resubmit the postinjection site care and site closure plan for the Di rector’s approval within 30 days of such change."

EPA is issuing guidance on development and updating of the GS project plans, including the postinjection site care and site clos ure plan. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: Rule Provision: 146.93(b)

API Comments: (b) The owner or operator shall monitor the site following the cessation of injection to show the pos ition of the carbon dioxide plume and
p ressure front and demonstrate that USDWs are not being endangered. (1) The owner or operator shall continue to conduct monitoring as specified in the Director-approved post-injection site care and site closure plan, for at least 50 years following the cessation of injection. At the Director ‘ s discretion, the monitoring will continue until th e geologic sequestration
p roject no longer poses an endangerment to USDWs. UNTIL CLOSURE IS AUTHORIZED PURSUANT TO §146.93(B)(3). (2) If The owner or operator ca n request and demonstrate to the satisfaction of the Director before 50 years, based on monitoring and other site

- specific data, that the geologic sequestration proj ect no longer poses an endangerment to USDWs, the Director may approve an amendment to THAT the post-injection site care and site closure plan SHOULD BE REVISED to reduce the frequency of monitoring or may authorize site closure before the end of the 50

- year p eriod.

Rationale: API, alon g with the MSDG, believes there are three problems with the Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24206closure standard in proposed section 146.93(b). First, the presumption that monitoring should continue for 50 years is unnecessary and counterproductive. A straight performance standard is preferab le to this or any other fixed time
p eriod because it provides a clearer standard and an incentive to maximize the understanding of site and project performanc e and as such is more protective of USDWs. Second, the proposal requires a showing that the CO2 plume has "stabilized", which is undefined. Cessation of plume movement is not necessarily essential to show that a project poses no threat of endangerment to USDWs-plumes that are still moving may, nonetheless, re main contained. Instead, it is more
p rotective to show that the plume is not expected to encounter a leakage
p athway. Third, the required showing that "no additional monitoring is needed" does not provide guidance regarding how an operator is to show that no additional monitoring is n eeded. The proposal below provides specific guidance on what the operator must show.

API, in concert with the MSDG, recomm ends the standard in the proposed alternative language for section 146.93(b) below because it sets forth detailed criteria, all of which must be satisfied, to demonstrate that the site does not
p ose an endangerment to USDWs. The specific criteria listed in our proposal will serve to provide the Director with th e requisite information to make the appropriate determination. The advantage of this approach is that it establishes clear criteria that an operator must demonstrate before obtaining site closure based upon particular site characteristics and is, therefore, reasonably applicable to any storage site as opposed to a standard based upon a fixedduration. Furthermore, it is more st ringent than a purely discretionary approach because it establishes specific cr iteria that must be shown before site closure may be granted. We believe this la nguage, which is an extension of work done by the World Resources Institute an d the Ground Water Protection Council, avoids the noted shortcomings and pr ovides stronger protection for USDWs.

Response: EPA disagrees with the suggested changes. As noted above, EPA disagrees that a postinjection site care timeframe of 50 years is excessive for most Class VI wells. EPA believes that a 50- year default post-injection site care timeframe, as requi red at §146.93(b)(1), is not overly burdensome, does not exaggerate the risks associated with GS, is consistent with other environmental programs, and sufficiently protects US DWs from endangerment.

EPA acknowledges the concerns of so me commenters that there will be circumstances where it can be demonstrated in less than 50 years that the pl ume and pressure front no longer pose a risk of endangerment to USDWs. For this reason, the Class VI rule offers owners or operators flexibility regarding the duration of the PISC timeframe by: (1 ) allowing the Director di scretion to shorten or lengthen the PISC timeframe dur ing the PISC period based on si te-specific data, pursuant to requirements at §146.93(b); or (2) affo rding the Director discretion to allow a Class VI well owner or operator to demonstrate, based on substantial data during the permitting process, that an alternative PISC timeframe may be appropriate if it ensures non-endangerment of US DWs pursuant to requirements at §146.93(c). EPA believes that a 50 year post-injection site ca re timeframe represents a reasonable and protective monitoring period and available data, including data submitted by commenters, do not support a different default timeframe. Furthermore, EPA believes that a 50- year default post-in jection site care timeframe, as required at §146.93(b)(1), is not overly burdens ome, does not exaggerate the risks associated with GS, is consistent with other envi ronmental programs, and su fficiently protects USDWs from endangerment.EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirement s of 146.92 and 146.93. Additionally, the guidance will assist Directors in evaluating proposed well plugging plans and post-injecti on site care and site closure plans required under 146.92 and 146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and monitoring wells, perform post-injection m onitoring, demonstrate the appropriateness of an alternative post-injection site care time fr ame, demonstrate non-endangerment, and perform site closure activities. This guidance will be available at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5280 2.8.2.4 USDW non-endangerment demonstrations Comment: Rule Provision: 146.93(b)(3)

API Comments: (3) Prior to authorization fo r site closure, the owner or operator MUST submit to the Director a demonstration , DEMONSTRATE TO THE DIRECTOR, based on monitoring, and other site-specific data, AND MODELING THAT IS REASONABLY CONSISTENT WITH SITE PERFORMANCE that the carbon dioxide plume and
p ressure front have stabilized an d that no additional monitoring is needed to assure that the geologic sequestration proj ect does not AND IS NOT EXPECTED TO
p ose an endangerment to USDWs. THE DIRECT OR SHALL APPROVE CLOSURE IF THE OWNER OR OPERATOR DEMONSTRATES, BASED ON THE CURRENT UNDERSTANDING OF THE SITE, INCLUDING MONITORING DATA AND/OR MODELING, ALL OF THE FOLLOWING: (I) THE ESTIMATED MAGNITUDE AND EXTENT OF TH E PROJECT FOOTPRIN T (CO2 PLUME AND THE AREA OF ELEVATED PRESSURE), (II) THE ESTIMA TED LOCATION OF THE DETECTABLE CO2 PLUME; (III) THAT THERE IS NO SIGNIFICANT LEAKAGE OF EITHER CO2 OR DISPLACED FORMATION FLUIDS THAT IS ENDANGERING USDWS; (I V) THAT THE INJECTED OR DISPLACED FLUIDS ARE N OT EXPECTED TO MIGRATE IN THE FUTU RE IN A MANNER THAT ENCOUNTERS A POTENTIAL LEAKAGE PATHWAY INTO A USDW; (V) THAT THE INJECTION WELLS AT THE SITE COMPLETED INTO OR THROUGH THE INJECTION ZONE OR CONFINING ZONE ARE PLUGGED AND ABANDONED IN ACCORDANCE WITH THESE REQUIREMENT S; AND (VI) ANY REMAINING PROJECT MONITORING WELLS AT THE SITE ARE BE ING MANAGED BY A PERSON AND IN A MANNER ACCEPTABLE TO THE DIRECTOR.

Rationale: API edits establish the performa nce based criteria for selecting the monitoring period. EPA should recognize th at under any given set of site specific conditions some of these crit eria may not be fully satisfied. EPA should retain the abilit y to waive individual monitorin g criteria described here Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24208to reflect that situation.

Rule Provision: 146.93(b)(4)

API Comments: (4) If such a demonstrat ion cannot be made (i.e., if the carbon dioxide plume and pressure front have not stabilized) after the 50

- year period, the owner or operator must submit to the Director a plan to continue post

injection site care.

Rationale: No longer necessary given changes above.

Response: EPA disagrees that the rule should specify the criteria for setting th e monitoring timeframe. Instead, EPA believes that such de terminations are site-specific and should be described in a project specific post-injection site care and site closure plan. EPA also be lieves that periodic reviews and updates, where necessary, to the plan are important to ensuring that the site continues to be managed effectively and to determine whether shortening the monitoring ti meframe is appropriate. The postinjection site care requirements in the final GS rule incorporate a combination of a fixed timeframe and a performance standard approach. The final GS rule offer owners or operators flexibility regarding the duration of the PISC timeframe by: (1) allowing the Director discretion to shorten or lengthen the PISC timeframe during the post-injecti on period based on site-specific da ta, pursuant to requirements at §146.93(b); or (2) affording the Direct or discretion to allow a Class VI well owner or operator to demonstrate, during the permitting pr ocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangermen t of USDWs pursuant to requirements at §146.93(c). EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts. EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and monitoring wells, perform post-injection m onitoring, demonstrate the appropriateness of an alternative post-injection site care time fr ame, demonstrate non-endangerment, and perform site closure activities. The guidance will be available at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment); 5260 2.8.2.3 Adjusting the post-injection timeframe (seeking comment) Comment: Rule Provision: 146.93(b)(4)

API Comments: (4) If such a demonstrat ion cannot be made (i.e., if the carbon dioxide plume and pressure front have not stabilized) after the 50

- year period, the owner or operator must submit to the Director a plan to continue post

injection site care. Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24209Rationale: No longer necessary given changes above.

Response: As described above, EPA believes that to en sure USDW protection from endangerment, a default timeframe for post-injection si te care is necessary in most ca ses. A 50-year post-injection site care timeframe represents a reasonable and protective monitoring period for most GS projects based on a review of research studies, i ndustry reports, and existing environmental programs, and evaluation of
p ublic comments. However, EPA recognizes that al ternative timeframes may be appropriate under limited, specific circum stances. For this reason, the Class VI rule offers owners or operators flexibility regarding the duration of the PISC timeframe by: (1 ) allowing the Director di scretion to shorten or lengthen the PISC timeframe dur ing the PISC period based on si te-specific data, pursuant to requirements at §146.93(b); or (2) affo rding the Director discretion to allow a Class VI well owner or operator to demonstrate, based on substantial data during the permitting process, that an alternative PISC timeframe may be appropriate if it ensures non-endangerment of US DWs pursuant to requirements at §146.93(c).

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Rule Provision: 146.93(e)

API Comments: (e) Once the Director has authorizeSd site closure, the owner or operator must submit a site closure report within 90 days that must thereafter be retained at a lo cation designated by the Director. AFTER COMPLETION OF ALL CLOSURE OPERATIONS. The report must include:

(1) Documentation of appropriate inje ction and monitoring well plugging as specified in §146.92 and paragraph (c) of this section. The owner or operator must provide a copy of a survey plat wh ich has been submitted to the local zoning authority designated by the Director . The plat must indicate the location of the injection well(S) relative to perm anently surveyed benchmarks. The owner or operator must also submit a copy of the plat to the Regional Administrator of the appropriate EPA Regional Office;

Rationale: Once the site closure report is submitted to the Director, the operator cease to bear responsibility for any further record retention. At this
p oint, EPA becomes the steward of information for the project.

Response: EPA disagrees that the owner or operator should not be responsible for record retention such as site closure reports. EPA believes that the require ments that the owner or operator retain, for ten years following site closure, records collected during the post-injecti on site care period at §146.93(f) and §146.93(h) are appropriate for the post-injection and site closure period to ensure that data are available to support non-endangerment de monstrations and to address any con cerns that may arise following site closure. This data will also suppor t EPA's review of project data as part of the adaptive rulemaking approach.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emer g enc y and remedial Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24210

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24211response (40 CFR 146.94) Comment: Rule Provision: 146.94(b)

API Comments: (b) If the ow ner or operator obtains evid ence that the injected carbon dioxide stream, DISPLACED FORMATION FLUIDS OR and associated pressure front may cause an endangerment to ENDANGERS a USDW, the owner or operator
must: (1) Immediately cease injection IN A PRUD ENT MANNER CONSIDERING CIRCUMSTANCES. (2) Take all steps reasonably necessary to identify and characterize THE ENDANGERMENT POSED; (3) Notify the Director or the designat ed representative within 24 hours OF BECOMING AWARE OF TH E ENDANGERMENT; and

Rationale: Technical clarifications.

There is a slight change that immediat ely ceasing injection c ould have adverse impacts on other aspects of the operation.

Response: After consideration of comments, EPA has finalized the rule language in §146.94(b) as
p roposed. In the introductory section of §146.94(b), EPA clarifies that the pressure front, as defined in §146.81, is a zone where the pressure differential is suff icient to cause the moveme nt of injected fluids or formation fluids into a USDW. Therefore, displ aced formation fluids are im plicitly included in the requirements for §146.94. EPA also clarif ies that owners or operators must take action when the CO2 stream or pressure front may caus e endangerment. In order to preven t the endangerment of USDWs, as required under §1421 of the SDWA, EPA expects the ow ner or operator to act preemptively and not wait until endangerment has occurred. This language is consistent with exis ting UIC requirements for other well classes and EPA’ s authority under the SDWA.

Regarding changes to the language in §146.94(b)(1), EPA believes that it is implicit that owners or operators should take care not to damage the well when ceasing injection. At §146.94(b)(2), EPA is maintaining the requirement to “cha racterize the release.” As currentl y written, the situation should be characterized whether or not a US DW has actually been endangere d, and owners or operators are encouraged to discuss with the Director whet her actual endangerment has occurred. Concerning commenters’ suggestions for §146.94(b )(3), EPA clarifies that the 24 hours begins when the owner or operator obtains evidence of possible endangerment. EPA believes the rule language is clear on this requirement.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: Rule Provision: 146.94(d)

API Comments: (d) The owner or operator must notify the Director prior to conducting any well workover IN RESPONSE TO ANY CASE OF ENDANGERMENT.

Rationale: In critical situat ions, time spent obtaining approval could adversel y affect the abilit y to conduct operations or increase the level of Commenter Name: Kyle Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24212endangerment.

Response: Since proposal, EPA has modified the final regulatory language at §146.94(d) to clarify what constitutes a workover to address a well failure (whi ch invokes remedial actions ) and what constitutes a maintenance-type workover. For maintenance-type workovers (i.e., those that are scheduled in advance), the owner or operator must notify a nd gain approval from the Director prior to beginning the workover. In the final GS regulation, EPA has moved this re quirement to the reporting requirements at §146.91(d) to clarify its intent.

Regarding concerns that notification could delay responses, EPA clarifies th at the GS rule, at §146.94 (b), describes procedures owners or operators must take in em ergency situations. Specifically, upon determining that there is a problem with the well that may endanger a USDW, the owner or operator must first cease injection, then take all steps reas onably necessary to identify and characterize any release, notify the Director, and implement the approved emergency and remedial response plan, which may include a well workover. EPA believes that ceasing injection (which the owner or operator would do immediately and before notifying the Director) is the immediate action ne cessary to prevent or mitigate endangerment of USDWs.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(2)(i)

API Comments: (i) Resistivity, spontaneous potential, and caliper logs before the casing is installed; and

Rationale: After a few wells are drilled in an area, these evaluations are frequently unnecessary and yi eld little new information. This is an example of where Director discretion may be appropriate.

Rule Provision: 146.87(a)(2)(ii)

API Comments: (ii) A Cement bond and variable density log, and a temperature log evaluation log(s) after the casing is set and cemented.

Rationale: Unusual to run these logs in a surface hole due to uniformity of shallow geology. This is an example of where Director discretion may be appropriate.

The proposed change provides more flexibi lity to select the appropriate log to demonstrate adequate cement bond.

Rule Provision: 146.87(a)(3)(i)

API Comments: Resistivity, spontaneous pot ential, porosity, ca liper, gamma ray, fracture finder logs and any other logs the Dire ctor requires BASED ON SITE SPECIFIC CONDITIONS AND RISK-BASED FACT ORS for the given geology before the casing is installed; and Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 29190Rationale: It is acceptable to specify basic logging requirements, however, special logs should not be specified. Any other information from the area should be used instead.

Rule Provision: 146.87(a)(3)(ii)

API Comments: (ii) A Cement bond and variable density log, and a temperature log EVALUATION LOG(S) after the casing is set and cemented.

Rationale: The proposed change provides more flexibility to select the appropriate log to demonstrate adequate cement bond.

Rule Provision: 146.87(a)(4)

API Comments: (4) A series of tests TEST(S) designed to demonstrate the internal and external mechanical inte grity of injection wells, which may include: (i) A pressure test with liquid or gas; (ii) A tracer survey DIAGNOSTIC TOOLS such as oxygen-activation logging; (iii) A temperature or noise log; AND/OR (iv) A casing inspection log. if required by the Director; and

Rationale: Technical and gr ammatical corrections

In (iv), "if required by the Director" is unnecessary, as it is in subsection (a)

Rule Provision: 146.87(a)(5)

API Comments: (5) Any alternative methods that provide equiva lent or better information and that are required of and/or approved of by the Director.

Rationale: Same comment as above in (iv).

Rule Provision: 146.87(b)

API Comments: (b) The owner or operator mu st submit to the Di rector A REPORT DESCRIBING whole cores or sidewall cores REPRESENTATIVE of the injection zone and confining system and formation fluid samples from the injection zone(s). The Director may accept DA TA FROM cores AND FLUID SAMP LES from nearby wells if the owner or operator can demonstrate that core retrieval is not possible and that such cores DATA are representative of conditions at the well IN THE WELLBORE. The Director may require the owner or operator to core other formations in the borehole.

Rationale: The information required should be sufficient to properly describe the injection and confining zones.

Response: EPA believes that all logs, surveys, and test s listed at §146.87(a) are necessary to verify information about the injection and c onfining zones and ensure that the well is being drilled and cased as approved, and has mechanical integrity. This informati on is needed to demonstrate that the well can beoperated and tested in a manner that protects USDWs from endangerment. While the tests do provide information on some of the same it ems, each provides unique data that build on each other and allow for interpretations not possible with a single test.

EPA notes that the Director has the discretion at §146.87(a)(5) to a pprove alternative methods that
p rovide equivalent or better info rmation. EPA believes that logs a nd tests must be performed on each well drilled regardless of existi ng information about the area to account for the complexity of CO2 injection well construction and the buoyancy of CO2. Existing litholog ic and geologic information may lack the details needed for site-s pecific well design and the geology needed to support protection of USDWs from endangerment.

EPA clarifies at §146.87(a)(2)(ii) a nd 146.87(a)(3)(ii) that ow ners or operators must perform a cement bond (i.e., cement evaluati on) log after the casing is set and cemented.

Regarding the comment on §146.87(a)(4)(ii), EPA disa grees that allowing the use of unspecified "diagnostic tools" would provide the same amount of information as the requirement to perform a tracer survey. The track record for tracer surveys in eval uating mechanical integrity has been proven over time. EPA clarifies that a tracer survey is one of the mechanical integrit y tests that may be required by the Director or used by the owner or operator. EPA ag rees with the commenter about the wording of the casing inspection log requirement and made the suggested change to improve clarity. In the final regulation, §146.87(a)(iv) does not include the phrase, “if required by the Director.”

Regarding the comment on §146.87(b), EPA cl arifies that it is not the Agen cy's intent that physical cores be submitted to the Director. In the final GS rule, EPA has revised the first sentence of §146.87(b) to read as follows: "The owner or operator must take whole cores or sidewall co res of the injection zone and confining system and formation fluid samples from the injection z one(s), and must submit to the Director a detailed report prepared by a log analyst that includes: well log analyses (including well logs), core analyses, and formation fluid sample information...."

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(c)

API Comments: (c) PRIOR TO INJECTION WELL OPERATION, the owner or operator must record PROVIDE REPRESENTATIVE INFORMATION ON the fluid FORMATION temperature, FORMATION FLUID pH and c onductivity, and reservoir pressure and the static fluid level of the injection zone(s).

Rationale: Technical correcti ons. Reservoir pressure and static fluid level are redundant parameters.

The phrase "representative information" pr events the operator from having to do all tests in all wells.

Rule Provision: 146.87(d)

API Comments: (d) At a minimum, the owner or operator must determine or calculate the followin g information concernin g the in j ection and confinin g Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 29200zone(s): (1) Fracture pressure; (2) Other physical and chemical character istics of the inj ection and confining zones; and (3) Physical and chemical characteristi cs of the formation fluids in the injection zone.

Rationale: With the excepti on of calculating fracture pressure, the requirements of this section appear redundant to othe r requirements of prior sections. The fracture pressure requirement has been added to section 146.87(e) below. (2) and (3) are too vague.

Rule Provision: 146.87(e)

API Comments: (e) (D) Upon completion but Prior to INJECTION WELL operation, the owner or operator must c onduct the following tests to verify hydrogeologic characteristics of the injection zone: (1) A pump test; or (2) Injectivity tests. ESTIMATE FRACTURE PRESSURES OF THE INJECTION AND CONFINING ZONES AND INJECTIVITY OF THE INJECTION ZONE. ESTIMATES SH OULD BE BASED ON REPRESENTATIVE HYDROGEOLOGIC AND GEOMECHANICAL CHARACTERISTICS OF THE INJECTION ZONE.

Rationale: Allows the use of information such as leak off tests conducted during the drilling operation.

The results of a pump test (pumping flui d from the well) have no relevance for an injection well.

Deletion of the injectivity test would al low the use of non-destructive methods to calculate fracture pressure.

Rule Provision: 146.87(f)

API Comments: (f) The owner or operator must provide the Director with the opportunity to witness all logging and testing by this subpart. The owner or operator must submit a schedule of such activities to the Director 30 days
p rior to conducting the first test UPON SPUDDING THE W ELL and NOTIFY THE DIRECTOR OF submit any changes to the schedule 30 days 48 HOURS prior to the next scheduled test.

Rationale: The changes reflect the realit ies of flexible rig schedules and operations. In addition, they are fully consistent with current Class II requirements and practices which deal with these issues on a daily basis.

Response: EPA disagrees that "reservoir pr essure" and "static fluid leve l" measurements required in §146.87(c) are redundant parameters. Alt hough the static fluid level is equal to the bottom hole pressure, this may not always be identical to the reservoir pr essure. Additionally, measuri ng the static fluid level
p rovides additional assurance that the reading is accura te (or, provides the needed information in caseswhere a good reading is not obtained). In addition, a st atic fluid level measurement provides information regarding the proximity to USDWs that need protection afforded to them.

EPA believes that the requirement to provide in formation on the injection and confining zones in §146.87(d) is warranted, and that the rule provides flexibility to acc ount for the variety of geologic conditions that may be encountered at GS sites.

EPA clarifies that the owner or operator has the opti on of using pump tests or in jectivity tests specified at §146.87(e) depending on which would provide the most valuable information based on site-specific conditions. Further, EPA disagrees that pump tests are irrelevant to determining injection zone
p roperties. Depending on the character istics or depth of knowledge of the confining and injection zone formations, pump tests may be necessary to prove that no hydraulic connection exists between the injection zone and a USDW. Additi onally, EPA disagrees that the wording at §146.87(d) would lead the owner or operator to employ destructive testing met hods for determination of fracture pressure. The wording "determined or calculated" allows for cal culations to be performed based on non-destructive methods.

EPA disagrees that the 30-day notification require ment is unreasonable. Acknowledging the developing nature of CO2 GS, EPA believes that involvement by the permitting authorit y in each project will
p rovide much needed field data for assurance of USDW protection from endangerment and will help update and refine the permitting process. Adequate timing of notificat ion will ensure the Director's ability to be involved.

Other EPA Comment Codes and Descriptions: 4000 2.4 Proposed Injection Well Operating Requirements ( 40 CFR 146.88) Comment: 146.88

(a)

Change first line to read: "Except dur ing stimulation and fracture breakdown
p ressure testing".

Response: EPA clarifies that approved well stimulation is the only situation where owners and operators may exceed the 90 percent injection pressure limitati on. The final rule at §146.91(d)(2) also requires that the owner or operator notify the Director 30 days before perfor ming stimulation during injection operations; this will provide an opportunity for the Di rector to review the owner or operator's plans for stimulation and add other requirement s as needed. EPA clarifies that UIC regulations prohibit fracturing of the confining zone at any time during injection or stimulation.

Other EPA Comment Codes and Descriptions: 5700 2.12 Comments on the proposed duration of Class VI permits (seeking comment) Comment: Part 144.36(a): The geologic sequestration of carbon dioxide is not a fully
p roven technology and much is unknown about th e long-term impacts, and potential unintended consequences of such injection. As previously state d, AWWA believes it would be prudent to limi t the life of the Class VI permit so that necessar y Commenter Name: Robert J. Finle y Letter ID: 0180 Commenter Or g anization: Illinois State Geological Survey Comment ID: 23635

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23719adjustments to the permit can be made as needed, with the opportunity for public comment. This will also establish a process for obtaining updated information on the injection operation. We would recommend a permit life of no more than 5 years. Therefore, AWWA recommends revising this part to read:

Permits for Class I and V wells shall be effective for a fixed term not to exceed 10 years. UIC Permits for Class II and III shall be issued for a period up to the operating life of the facility. Permits for Class VI wells shall be effective for a fixed term not to exceed 5 years.

Response: The final rule maintains the li fetime permit provision and clar ifies that the permit extends through the post-injection si te care period (144.36(a)). However, it also adds a requirement that the Director review each Class VI permit at least every 5 years to determine whether it should be modified, revoked and reissued, terminated or a minor modification ma de as provided in §§144.39, 144.40, or 144.41. The Director’s review will be informed by the owners’ or operato rs’ iterative reevaluation of the GS project. Specifically, the final rule includes a re quirement that the AoR be reevaluated at least every five years, and also requires owners or operators to review and update the AoR and corrective action
p lan, the testing and monitoring plan, and the emergency and remedial response plan throughout the life of the project (146.84(e), 146.90(j), and 146.94(d)). Owners or operators must review each plan and identify necessary amendments or demonstrate to the Director that no amendment is needed. In no case can reviews occur less often than once every five years. The iterative process and subsequent plan reevaluations ensure that time and resources are commit ted to the most critical aspects of the permit in
p reventing endangerment to USDWs.

EPA believes that the iterative process of devel oping and executing the various plans required of GS well operators in the final rule (e.g., for AoR and corrective action, testing and monitoring, well
p lugging, and post-injection site care , and emergency and remedial response) is tailored to the unique aspects of—and is more appropriate for–GS than esta blishing a finite permit dur ation (e.g., five years as suggested by some commenters). This is pref erable to a periodic pe rmit reapplication.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions; 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: Part 146.5(f): There is the possibility th at some of the geologic sequestration activities will occur in areas where ther e are no USDWs located in the area of review. These wells should st ill be permitted as Clas s VI wells, and AWWA recommends revising the Class VI definition to:

(f) Class VI. Wells used for geologic sequestration of carbon dioxide in the following applications: 1. Where carbon dioxide is injected belo w the lowermost formation containing a USDW; and, 2. Where carbon dioxide is injected in fo rmations where no USDWs exist within the zone of elevated pressure associated with the injection well.

Wells used for the geologic storage of carbon dioxide in formations above the lowermost USDW are prohibited.

This definition would capture all wells associated with g eolo g ic carbon Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23720sequestration activities whet her or not a USDW was pr esent in the projected footprint of the project.

Response: In the final rule EPA will allow injection into non-USDWs above or between the lowermost USDW where owners or operators can demonstrate th at such injection can be performed in a manner that protects USDWs from enda ngerment, as long as appropriate protections are in place.

EPA adds that, in the final rule at §144.6 (f), Cl ass VI wells are defined as wells that are not experimental in nature that are used for geologic sequestration of carbon dioxide beneath the lowermost formation containing a USDW; or, wells used for ge ologic sequestration of carbon dioxide that have been granted a waiver of the in jection depth requirements pursuant to requirements at §146.95 of this chapter; or, wells used for geologi c sequestration of carbon dioxide that have received an expansion to the areal extent of an existing Class II enhanced oil recovery or enhanced gas recovery aquifer exemption pursuant to §§146.4 of this chapter and 144.7(d).

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: Part 146.82(b) AWWA recommends revising the second to the last sentence to read:

The map should also show faults and ot her major geologic discontinuities, if known or suspected.

Response: Based on its evaluation of all public commen ts and input on the proposed rule and the N ODA and Request for Comment EPA has made many revi sions to the GS rule. Pl ease see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: Part 146.82(b) AWWA recommends that the last sentence be deleted from this part. Owner/operators should be required to go beyond the data available in the public record to identify some of the features listed in this requirement. For example, the owner/operator s hould be required to do its due diligence to identify all abandoned wells, plugged wells or old bore holes in the area of review. While
p ublic records may be a good starting point for the identification of these features, given the fact that some of the existing wells could be decades old, it is hard to believe that records woul d exist for every one of them. EPA should mandate that owner/operators use well identification technol ogy to locate any existing wells that are not listed in the public record.

AWWA recommends revising this part to read:

A surface map showing the injection well(s) for which a permit is sought and the applicable area of review. Within the area of review, the map must show the number, or name and location of all inje ction wells, producing wells, abandoned wells, plu gg ed wells or dr y holes, deep strati g raphic boreholes, State or EPA Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23724

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23725approved subsurface cleanup sites, surf ace bodies of water, springs, mines (surface and subsurface), quarries, wate r wells and other pertinent surface features including structures intended fo r human occupancy and roads. The map should also show faults, if known or su spected. The owner or operator must include all information available in th e public record, as well as conducting independent site investigati ons to locate any of the above features that may not be identified in the public record.

Response: EPA believes that a determination about whethe r data/information is outside or within the
p ublic record will be site-specific, and based on knowle dge of the site, data avai lability, and data quality. For instance, in meeting the requirement to tabulate information on wells in the AoR, the Director has the discretion to require the owner or operator to supplement a data records search, including requiring ground or airborne surveys for wells, if there is reason to believe, ba sed on knowledge of the site or of available data bases, that the incompleteness of available information could compromise USDW
p rotection from endangerment.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: Part 146.82 (c) AWWA recommends re vising this part to read:

A map delineating the area of review based upon modeling, using all available data including data obtained during geophysic al logging and testing of the well and the formation as required by paragraphs (l), (r), and (s) of this section.

Response: EPA clarifies that the map of the AoR must re flect the model inputs, including the extensive geologic information, data collected during the site characterization process (e.g., information about artificial penetrations), and anticipated operating parameters (e.g., injection rates) submitted with the
p ermit application under 146.82. EPA adds that the fina l rule, at §146.82(c)(1), requires that the final area of review be “ b ased on modeling, using data obtained during logging and testing of the well and the formation...”

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: Part 146.82(d)(1) AWWA recommends revising this part to read:

Isopach maps of the area of review, including the proposed injection and confining zone(s), a structural contour map hung on the top of the proposed injection zone, and at least two geologic cross sections of the area of review showing the geologic formations fr om the surface to total depth.

Part 146.82(d)(2) AWWA recommends revising this part to read:

Location, orientation, and properties of known or suspected subsurface faults, fractures, and other disconti nuities that may transect the confining zone(s) in the area of review and a determination that the y would not interfere with Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23726

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23727containment.

Part 146.82(d)(3) AWWA recommends revising this part to read:

Information on the seismic history within the proposed area of review including
p resence and depth of seismic sources, know ledge of previous seismic events and history of these events, and a determin ation that the seismicity would not interfere with containment.

Part 146.82(d)(4) AWWA recommends revising this part to read:

A spreadsheet with data on the depth, areal extent, thickness, mineralogy,
p orosity, permeability, capillary and reservoir pressure of the injection and confining zone(s) within the area of review; including any geologic/facies changes based upon field data which may include geologic cores, outcrop data, seismic surveys, well logs, and na mes and lithologic descriptions.

Part 146.82(d)(5) AWWA recommends revising this part to read:

Geomechanical information on fractures, st ress, ductility, rock strength, and in situ fluid pressures on the injection a nd confining zones within the area of review.

Part 146.82(e) AWWA recommends revising the first sentence to read:

A spreadsheet of all wells and other artifi cial penetrations within the area of review which penetrate the inje ction or confining zone(s).

Part 146.82(f) AWWA recommends re vising this part to read:

Potentiometric (water level) surface maps and stratigraphic cross sections indicating the general vertical and lateral limits of all USDWs including existing aquifers not meeting the definition of a USDW th at are either currently being utilized as private or public water supplies or are identi fied as a future water supply, water wells and springs within the area of review, their positions relative to the injection zone(s) and the direction and ve locity of water movement. At least two geol ogic cross sections showing the thickness and general vertical and lateral limits of all USDWs within the area of review.

Part 146.82(g) This part should provide a list of the formations for which baseline geochemical data s hould be obtained. AWWA recomm ends revising this part to read:

Collection of baseline geochemical data on the subsurface formations, including all USDWs in the area of review. At a minimum, geochemical data should be
p rovided for the injection formation, the confining zone immediately above the injection zone, the nearest adjacent por ous and permeable formation to the confining zone, all USDWs in the area of review including existing aquifers not meeting the definition of a USDW that ar e either currently being utilized as
p rivate or public water supplies or are id entified as a future water supply, as well as for any additional format ions as required by the Director.Part 146.82(h)(1) AWWA recommends revising this part to read:

Average and maximum daily injection ra te and volume of the carbon dioxide
stream.

Part 146.82(h)(2) AWWA recommends revising this part to read:

Average and maximum surface injection pressure;

Part 146.82(k) AWWA reco mmends revising this part to read:

Proposed stimulation program and a determination that stimul ation will not interfere with or breach the confining layer.

Part 146.82(n) AWWA reco mmends revising this part to read:

Engineering drawings of the surface and subsurface construction details of the system, including design featur es for surge control and water hammer protection, including the following:

(i) Record drawings, based upon inspections by the engineer of record or persons under his direct supervision, wi th al deviations noted; (ii) Copies of the mill certificates of all casings used in the construction of the well; (iii) Certification of completion subm itted by the engineer of record; (iv) An operation manual incl uding emergency procedures; (v) Proposed monitoring program and data to be submitted; (vi) Proof that the existence of the we ll and any associated monitoring wells have been recorded with the permanent wa rranty deed or other instrument of conveyance as a two page proviso or adde ndum that contains cer tification of the locations of the wells (by metes and bounds) and a detailed sketch of the parcel that shows the location of the well. The location shall be measured by a certified land surveyor, and shall c ontain the surveyor's signature, registration number, offici al seal, and the following statement: "I hereby certify that this survey was made under my responsible direction and supervision, and is a correct representation of the land surveyed."

Part 146.82(q) As the Director should approve the corrective action plan prior to any activities taking place within th e area of review, AWWA recommends revising this part to read:

The plan for corrective acti on on artificial penetrations within the area of review and the status of any correction actions, if previously approved by the Director.

Part 146.82(s) As the well should not yet be constructed when the owner/operator applies for the permit, the demonstrati on of mechanical integrity should not have occurred yet. Therefore, AWWA r ecommends revising this part to read:

The proposed demonstration method for m echanical integrity pursuant to §146.89.Part 146.82(v) As monitoring wells may also have to be plugged, AWWA recommends revising this part to read:

Proposed injection and moni toring well(s) plugging plan required by §146.92(b).

Response: EPA disagrees that the suggested revisions are necessary. While EPA acknowledges and agrees with the importance of many of the specific items the commenter suggest s adding to the text, the Agency believes that it is important to allow some flexibility to address the varied and site-specific conditions at GS sites. EPA antici pates that the iterative process by which owners or operators submit and Directors review geologic and other information to support the pe rmit application will promote the most effective approach to addressi ng USDW endangerment. EP A adds that if the Di rector believes that additional information is needed to support a determina tion about the suitability of a proposed site, it is within his/her authority to request it.

EPA notes that the final rule does include reference to capillary pressure in §146.82(a)(3)(iii), “Data on the depth, areal extent, thickness, mineralogy, poros ity, permeability, and capi llary pressure of the injection and confining zone(s); including geology/facies changes base d on field data which may include geologic cores, outcrop data, seismic surveys, well logs, and names and lithologic descriptions.”

EPA agrees that not all of the in formation listed at §146.82 of the propos ed regulation will be available at the time the owner or operator develops their initial pe rmit application. In response to comments and based on an evaluation of the proposed requirements at §146.82, the Agency revised this subpart so that the final regulation specifi es separate requirements for information to be submitted with the permit application and before well construction is approved (at §146.82(a)) and inform ation to be submitted before operation of the well is authorized (at §146.82(c)).

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators and Directors in evaluating permit requirements and applications under §146.82. The guidance provides recommendations regarding charac terizing the regional geology and hydr ogeology of a proposed GS site as well as performing the necessary geochemical, geomechanical, and geophys ical analyses of the injection and confining zone. The guida nce can be found on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: Part 146.83(a)(1) AWWA recommends revising this part to read:

An injection zone of sufficient areal extent, thickness, porosity, and
p ermeability to receive the total anti cipated volume of the carbon dioxide stream, and at a depth with sufficient overburden pre ssure to keep the carbon dioxide stream as a supercritical fluid.

Response: EPA disagrees that the GS rule should require that the CO2 remain in a supercritical state. EPA believes that, in many cases CO2 will be inject ed at depths where it will remain supercritical. However, the final rule does not require that it remain in a superc ritical state once it is injected; nor does the rule preclude the injection of gaseous CO2 into shallower non-USDWs provided that the owner or operator meets the Class VI requirements and ensures protection of USDWs from endan g erment. Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23728Other EPA Comment Codes and Descriptions: 3120 2.1.2 Need to identify additional confining and containment zones (seeking comment) Comment: Part 146.83(b) This part of the rule s hould a requirement, not an option that can be requested at the discretion of the Director. While it is possible that a site with a single confining can provide storage integrity, AWWA recommends that additional confining layers at the site be characterized to get a better estimate of leakage risk to USDWs and possibly identify additional monitoring zones. It is important to know if these zones exist, and to have adequately documented their characteristics, to evalua te and demonstrate the possibility of secondary containment. AWWA recomme nds revising this part to read:

Owners or operators of Clas s VI wells must identify and characterize additional zones that will impede vert ical fluid movement, are free of faults, fractures or other discontinuities that may interfere with containment, allow for pressure dissipation, and provide additional opportuni ties for monitori ng, mitigation and remediation.

Response: EPA agrees with the commenter that, in some situations, the presence of additional confining and containment zones above the primary (i.e., lowermost) confining zone can improve USDW
p rotection from endangerment. EPA di sagrees that secondary confining zones are required at all sites, e.g., where a primary confining zone that free of transmissive faults or fractures and of sufficient areal extent and integrity to contain the injected carbon dioxide stream and displaced formation fluids and allow injection at proposed maximu m pressures and volumes without in itiating or propa gating fractures in the confining zone(s) (per §146.83(a) ) is demonstrated to be present. The final regulation retains the requirement at §146.83(b) which afford s the Director discretion to re quire owners or operators to identify and characterize additional zones.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Part 146.84 It is important to note that the carbon dioxide plume will never cease moving. Even deep formations have a natural flow gradient, and it is likely that there will always be some movement due to changes in density gradients and diffusion. This should be considered when defining the AoR for each project.

Response: EPA agrees with the commenter that there ma y be cases where movement of the CO2 plume will never cease due to gradient, diffusion, and density gradients, but disagrees that the AoR definition at 146.84(a) should describe a never-ending timefr ame of CO2 plume movement. The GS regulation recognizes that plume movement may stabilize to a point where movement of the CO2 plume slows or
p ressures in the injection zone sufficiently decline to the point that they no longer pose an endangerment to USDWs, although move ment does not completely cease. EPA believ es that in all cases, these criteria will be met at some point after the cessation of injection. As discus sed in the preamble to the proposed GS regulation and the associated background doc ument "Computational Modeling of Underground In

j ection of Carbon Dioxide for Determination of Area-of-Review and Potential Risk to Under g round Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23729

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23730Sources of Drinking Water" (cited in the propos ed rule preamble as USEPA, 2008d), research has shown that CO2 may continue to migrate fo r a period of time af ter injection ceases.

For this reason, the GS regulation does not specify a timeframe over which the AoR delineation model should run. Rather, the model should be used to predic t the ultimate plume movement up to the point the
p lume movement ceases or pressures in the injection zone sufficiently decline to the point that they no longer pose an endangerment to USDWs.

EPA believes that an iterative process of AoR reevaluation is appropriate to verify that the CO2 plume and pressure front are moving through the subsurface as predicted, verify the acc uracy of the delineation model (or identify needed changes), and refine test ing and monitoring activities to ensure that USDWs are protected from endangerment and that there would be adequate warning of potential problems at the site before any endangerment could occur. EPA adds that the requirement at 146.93(b) for post-injection site care further ensures that a ny continued movement of the CO2 pl ume and pressure front will be addressed until it can be demonstrated that the GS operation no longer poses an endangerment risk to USDWs.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Part 146.84(c)(1)(iii) AWWA recommends revising this part to read:

Consider potential migration through faul ts, fractures, other discontinuities and artificial penetrations.

Response: EPA did not change 146.84(c)(1)(iii) but instea d changed the text at 146.84(c)(1)(ii) to read as follows: "Take into account any geologic heterogeneities, other discontinuities, data quality, and their
p ossible impact on model predictions" to address th e water association commenter's concern regarding the potential for migration of CO2 at GS sites.

Other EPA Comment Codes and Descriptions: 3200 2.2 Proposed Area of Review and Corrective Action Requirements (40 CFR 146.84) Comment: Part 146.84(c)(2) AWWA recommends revising the first sentence to read:

Using methods approved by the Director, identify all penetrations, including active and abandoned wells and underground mines, in the area of review that may
p enetrate any portion of the confining zone.

Response: EPA clarifies that the mapping and cross s ections required to be submitted under 146.82(a) (3) will define the limits of the confining zone, which would be accounted for in the AoR delineation and corrective action evaluation requi red at 146.84(c). EPA adds that ow ners or operators must also, under 146.82(a)(2), submit a map of the AoR that show s all injection wells, producing wells, abandoned wells, plugged wells or dry holes , deep stratigraphic boreholes, State or EPA approved subsurface cleanup sites, surface bodies of water, springs, mines (surface and subsurface), quarries, water wells and other pertinent surface features including structur es intended for human occupancy and roads. EPA b elieves that these requirements a ddress the commenter's concerns. Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23731

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23732EPA adds that any well that penetr ates the confining zone , even if it does not extend all the way through the confining formation, is to be included in the tabulation. EPA is issuing guidance on how to identify all wells that require corrective action. The guidance describes EPA' s recommended approaches for the data to be considered in an initial AoR delineat ion, how to apply computational modeling to delineate the AoR, performing corrective action at GS sites, and, when appropriate, completing AoR reevaluations. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) Comment: Part 146.84(d) Based upon our comments in the previous section of this document, AWWA recommends revising this part to read:

At the minimum fixed frequency, not to ex ceed one (1) year for the first ten (10) years of the operation of the carbon sequestration project and not to exceed five (5) years after the first ten year time period, as specified in the approved area of review a nd corrective action plan, or when monitoring and operational conditions warrant, owners or operators must:

Response: EPA agrees with commenters that reevaluati ons of the AoR every ten years may not be sufficient to appropriately model plume and pressure front movement, establish conditions for corrective action, and ensure protection of US DWs from endangerment. For these reasons, the Agency changed the minimum frequency for the AoR reevaluation at §146.84(e) from 10 years to at least every 5 years in the final GS rule. EPA believes that this revised fr equency addresses commenters' concerns about the inherent uncertainties in modeling CO2 movement, the emerging nature of GS technology, risk-based targeting of monitoring activities, and the unique nature of CO2 GS. In addition, the Director has discretion to require more frequent AoR reevaluation if he or she has reason to believe, based on sitespecific information, that a five-y ear reevaluation schedule is not sufficiently protective of USDWs.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Part 146.85(b) AWWA believes that potential changes in the size of the area of review require that all site plans be reevaluated at th e same frequency as the area of review. Therefore, AWWA recommends revising this part to read:

The owner or operator must provide to the Director, at the same frequency as the AOR reevaluation, written updates of adjustme nts to the cost estimate to account for any amendments to the area of re view and corrective action plan (§146.84), the testing and monitoring plan (§146.90), the injection well plugging plan (§146.92), the post-injecti on site care and site closure plan (§146.93), and the emergency and remedial response plan (§146.94).

Response: EPA agrees that it is important to periodical ly update cost estimate s that support financial responsibilit y determinations. The final GS rule, at §146.85(c) , requires the owner or operator to provide Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23733

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23734updates to the cost estimate within 60 days of a ny amendments to the AoR and corrective action plan, the injection well plugging plan, the PISC and site closure plan, and the emergency and remedial response plan. Owners or operators must also ad just the estimates for inflation annually under §146.85 (c)(2). EPA adds that the Di rector can also require the owner or ope rator to provide an adjustment of the cost estimate if the Director de termines that the original demons tration is no longer adequate, as specified at §146.85(e).

Other EPA Comment Codes and Descriptions: 3800 2.3 Proposed Injection Well Construction Requirements ( 40 CFR 146.86) Comment: Part 146.86(b)(1) AWWA recommends revising the second to the last sentence to read:

The casing and cementing program must be designed to prevent the movement of fluids into or between USDWs and between the injection zone(s) and USDWs.

Response: EPA believes that the existing language as writ ten ensures the prohibition of fluid movement between the injection zone and any USDW and the suggested change is unnecessary. Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3862 2.3.3.1 Use of corrosion- resistant construction materials (seeking comment) Comment: Part 146.86(b)(1)(v) The corrosiveness ev aluation should include the possible combining of the carbon dioxide stream and the injection zone water, which has a higher potential to corrode than the carbon dioxide alone. AWWA recommends revising this part to read:

Corrosiveness, chemical co mpatibility and reactivity of the carbon dioxide stream and the formation fluids located within the injection zone.

Response: EPA clarifies that reference to corrosivenes s of the CO2 stream in §146.86 refers to the
p otential for CO2 to be corrosive in the presence of wa ter or formation fluids. EPA believes that the risk of creating acidic fluids that could come in contact with well materials and cem ents is addressed by the construction requirements in §146.86 to ensure protection of USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements (seeking comment) Comment: Part 146.86(b)(1)(viii)AWWA recommends revising this part to read:

Type or grade of cement and chemical co mpatibility and reactivity of cement and formation fluids located within the in j ection zone. Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23735

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23736

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23737Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS rule. Please see the final rule and the discussion of financial responsibility in the preamble for additional information.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Part 146.87(b) AWWA suggests that submittal of the cores to the Director is not very practical. The requirement should be rewritten to state that the Director should be provided with a summary repor t describing the cores and the test results. The operator should be required to first submit a coring plan to the Director listing the intervals to be co red, the coring procedures, the tests to be conducted and proposed storage of the core for review and consideration of approval by the Director. A core report, including the test results, geomechanical characteristics , and values calculated fro m the testing, such as fracture gradient, should be submitted to the Director. The owner/operator should make the cores available for insp ection by the Director upon the request. AWWA recommends revising this part to read:

The owner or operator must submit to the Director a report describing whole cores or sidewall cores representative of the injection zone and confining system and formation fluid sa mples from the injection z one(s). The Director may accept data from cores and fluid samples from nearby wells if the owner or operator can demonstrate that such data ar e representative of conditions at the well. The Director may require the owner or operator to core other formations in the borehole to acquire more information on the subsurface geologic characteristics.

Response: EPA clarifies that it is not the Agency's in tent that physical core s be submitted to the Director. In the final GS rule, EPA has revised the first sentence of §146.87(b) to read as follows: "The owner or operator must take whole cores or sidewall cores of the in jection zone and confining system and formation fluid samples from the injection zone(s), and must submit to the Director a detailed report
p repared by a log analyst that includes: well log an alyses (including well logs), core analyses, and formation fluid sample information...."

Other EPA Comment Codes and Descriptions: 4110 2.4.1.1 Injection pressure limitations Comment: Part 146.88(a) AWWA is concerned that th e limitation on injection pressure to 90% of the fracture pressure is not stringent enough. We he ard it stated at the
p ublic hearing in Denver that fracturing of the injection formation can occur when injection pressures are below 90% of the fracture pressure. It is important to consider that injection pressure limitations need to take account of the
p ossibility that, under certain conditions, faults can be re-activated even if injection pressures are kept below the le vel necessary to create new fractures or propagate existing fractures. Therefor e, the regulation should provide for the in j ection pressure to be calculated based on the site g eolo gy , h y dro g eolo gy Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23738

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23739and geomechanics, in combination with the injection pressure limitation. Injection pressures and rates should be determined by well tests and geomechancial studies, taking into account both formation fracture pressure and formation parting pressure. However, due to the amount of uncertainty associated with this topic, AWWA recommends that EPA research their pr oposed limitation in more detail to determine the best met hod for preventing possible contamination of USDWs. Therefore, we recomme nd revising this part to read:

The owner or operator must ensure that injection pressure and rates remain within limits established by permit. Such permit limitations shall be based on well tests and geomechanical studies, incl uding assessments of both the fracture
p ressure of the confining zone and the pa rting pressure of the confining zone. In no case may injection pressure init iate or propagate fractures in the confining zone, cause otherwise non-tran smissive faults transecting the confining zone to become transmissible, otherwise degrade the integrity of the confining zone, or cause the movement of injection or formation fluids that endangers a USDW.

Response: EPA agrees that the operator must remain with in limits established by the Class VI permit. EPA clarifies that the owner or operator is re quired in §146.82(a)(7) to propose a maximum injection
p ressure as part of the permit application. The proposed injection pr essure will be evaluated by the Director based on site-specific conditions, and be informed by data on the injection zone. During injection, the pressure in the injection zone must not exceed 90 percent of the fracture pressure of the injection zone, as specified at §146.88(a). The fracture pressure (and, th erefore, the injection pressure) are based on site-specific geologic and geomechanical data collected during the site characterization
p rocess required at §146.82. If, based on this information, a lower pressure limitation is appropriate, the Director has the authority to set a lower limit in the operating permit.

In response to the concern about reopening of faults at lower pressures than 90 percent of fracture
p ressure, EPA believes that the requirement for th e owner or operator to submit data on known or suspected faults and fractures and information on the seismic history of the site will inform the determination of an appropriate pr essure limitation in the permit. Any sites with the potential for reopening or reactivation of faults or unacceptable seismic risk that could otherwise interfere with containment will not be permitted as GS sites.

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators in meeting the requirements of §146.82 a nd to assist directors in eval uating permit applications. The guidance will describe recommended approach es for characterizing the regional geology and hydrogeology of a proposed site and performing th e necessary geochemical, geomechanical, and geophysical analyses of the inject ion and confining zone. EPA is al so developing guidance for primacy agencies that will include recommended approaches for evaluating owner or operator-submitted data in setting permit conditions. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4000 2.4 Proposed Injection Well Operating Requirements ( 40 CFR 146.88) Comment: Part 146.88(b) AWWA recommends revising this part to read: Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23740Injection of the carbon dioxide stream be tween the outermost casing protecting USDWs and the well bore is prohibited.

Response: EPA retains the provision as propos ed, and clarifies that injection between the casing and the well bore is prohibited. This is cons istent with requirements for other injection well classes in the UIC
p rogram.

Other EPA Comment Codes and Descriptions: 4500 2.5 Proposed Mechanical Integrity Testing (MIT) Requirements (40 CFR 146.89) Comment: Part 146.89(f) AWWA recommends re vising this part to read:

The Director may require additional or alternative tests if the results
p resented by the owner or operator under pa ragraph (d) of this section are not satisfactory to the Director to demonstrat e that there is no significant leak in the casing, tubing or packer or significant movement of fluid into or between USDWs, or between the injection zone(s) an d USDWs, resulting fr om the injection activity as stated in paragraphs (a)(1) and (2) of this section.

Response: EPA clarifies that the regulations at §146.89(e) allow the Director to require additional methods or, with the Admi nistrator's approval, to approve the us e of alternative MIT methods based on specific information about the site or the well.

EPA believes that the MITs described in the rule at §146.89 are effective meth ods and have been used successfully by injection well operators for decades and provide an important ea rly warning of potential
p roblems in the injection well system.

In addition, EPA is using an adaptive approach to regulating GS. The Agency plans to collect and review data every six years on GS projects to determine whether th e appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Part 146.90 AWWA recommends revi sing this part to read:

The owner or operator of a Class VI well must prepare, maintain, and comply with a testing and monitoring plan to verify that the geologic sequestration project is operating as permitted and is not endangering USDWs. The testing and monitoring plan must be submitted with the permit applicat ion, for Director approval, and must include a description of how the owner or operator will meet the requirements of this section. The testing and monitoring plan must be reviewed and updated, as necessary, on th e same schedule as the update to the Area of Review.

Response: EPA a g rees that periodic updates to the plan are a ppropriate. EPA clarifies that the final GS Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23742

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23743regulation includes a requirement that the AoR be reeval uated at least every 5 year s, and it specifies at §146.90(j) that the operator revise the testing and monito ring plan to incorporate the results of the most recent AoR reevaluation and recent operational and m onitoring data. Based on its evaluation of all
p ublic comments and input on the proposed rule a nd NODA and Request for Comment EPA has made many revisions to the GS rule. Se e the final rule and preamble for further discussion on EPA's final approach.

EPA agrees with commenters that developing a nd following testing and monitoring plans is an important part of assuring that a GS project is opera ting properly and is crucial for the early detection of
p otential endangerment to USDWs.

Other EPA Comment Codes and Descriptions: 4655 2.6.5.1 Plume tracking techniques/geophysical methods (seeking comment) Comment: Part 146.90(g) AWWA recommends revising this part to read:

Testing and monitoring to track the extent of the carbon dioxide plume and the
p osition of the pressure front by either monitoring for pressure changes in the confining zone, in the first formation overlying the confining zone or using indirect, geophysical tec hniques (e.g., seismic, electrical, gravity, or electromagnetic surveys and/or down-hol e carbon dioxide detection tools);

Response: EPA has revised the final GS regulation, at §146.90(g)(1), to re quire all GS project owners or operators to mon itor for pressure changes in the inject ion zone. EPA believ es that pressure monitoring in the injection zone is necessary to tr ack the development and movement of the pressure front and CO2 plume. Pressure m onitoring within the injection zone is necessary because any such monitoring above the confining zone would not detect movement of the pressure front unless a breach o f the confining zone occurs. EPA believes that monito ring using wells in the in jection zone (i.e., that
p enetrate the confining zone) can be safely perfor med if the wells are cons tructed to prevent flow between the injection zone and US DWs or other layers above the c onfining zone. Such construction technologies exist and have been used in the oil and gas industry for years. EPA believes that the benefits of monitoring in the in jection formation outweigh the mana geable risk of those monitoring wells serving as conduits for fluid movement. EPA adds that owners or operators may consider and Directors may require performing a dditional pressure monitoring in we lls that are above the confining zone (e.g., in the same wells used to perform gr ound water quality monitoring required at §146.90(d)) to
p rovide additional verification that no pressure cha nges are occurring above the confining zone due to CO2 leakage. Monitoring also identifies needed re medial actions, provides inputs for AoR reevaluation modeling, and targets additional geochemical and su rface monitoring needs. K nowledge of the location of the CO2 plume and the associated pressure fro nt will assure the public that GS projects are
p roceeding according to plan, provide sufficient information to the owner or operator and Director, or allow for appropriate actions to address a ny indication that USDWs may be endangered.

In addition, §146.90(g)(2) requires owne rs or operators to track the position of the CO2 plume using indirect methods (e.g., seismic, el ectrical, gravity, or electromagne tic surveys and/or down-hole CO2 detection tools), unless the Director determines based on site-specific geology, that such methods are not appropriate.

EPA acknowledges that, at ce rtain sites, there may be a need for more or different monitoring schemes (which ma y include monitorin g in the confinin g zone), and adds that it is important to balance the need Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23744for adequate monitoring that ensures USDW protec tion from endangerment agai nst too many artificial
p enetrations which could serve as conduits for fluid migration. Site-specific te sting and monitoring plans must describe the proposed monitoring regime , which must be approved by the Director. Flexibility is also provided regarding how to monito r for the specific data required by the final rule. The testing and monitoring plan is developed by the owner or operator in consultati on with the Director and is designed to ensure that a detailed, Director -approved document describing how monitoring will be conducted during the lifetime of the project exists.

EPA is developing guidance on testing and monitoring to assist owners or opera tors and Directors in evaluating requirements under §146.90, in cluding proposed monitoring pl ans. The guidance describes available technologies and recommended approaches for implementing a test ing and monitoring plan, including pre-operational geophys ical logging and test ing of injection wells, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Part 146.90(h)(1) AWWA recommends revising this part to read:

The testing and monitoring plan must be based on site-specific geologic factors, modeling, and a risk-assessment of potential vulnerabilities wi thin the area of review;

Response: As described above, EPA agrees that periodic updates to the plan are appropriate, and the final GS regulation includes a requirement that the Ao R be reevaluated at leas t every 5 years, and it specifies at §146.90(j) that the operator revise the test ing and monitoring plan to incorporate the results of the most recent AoR reevaluation and recent opera tional and monitoring data . Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS ru le. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4760 2.7.6 Proposed reporting frequency (seeking comment) Comment: Part 146.91(11)(a) AWWA believes that the reporting frequency should be on a monthly basis, similar to what water and wa stewater treatment pl ants have to do. The operating information for the geologi c sequestration project is extremely important and needs to be reviewed at a frequency by the regulatory agency to ensure problems are identified and addre ssed in a timely manner. For example, with the way the regulation is currently structured, data collected on July 1, 2008 would not be seen by the regulatory agency before January 15, 2009, if the operator is allowed 15 days to submit th e report. This would allow for very little time to correct any potential issues in the opera tion of the project. As such, AWWA recommends revisin g this part to read: Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23745

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23746Monthly reports, due on the 15th day of ea ch month for the previous month’s activities, containing:

Response: As described above, the final rule remains unchanged from the propos al and requires semiannual reporting of monthly average, maximum and mi nimum values for injection pressure, flow rate and volume, annular pressure, and monthly annulus fluid volume adde d at §146.91(a). EPA believes that monthly reporting of routine opera tional data and monitoring resu lts would provide no additional
p rotection of USDWs from endangerment.

For additional information, please see the final rule and the preamble for a discussion of EPA's final approach to recordkeeping and reporting.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Part 146.92(b) As previously stated AWWA be lieves that potential changes in the size of the area of review require that all site plan s be reevaluated at the same frequency as the area of review. Ther efore, AWWA recommends revising this
p art to read:

Well Plugging Plan. The owner or operator of a Class VI well must prepare, maintain, and comply with a plan that is acceptable to the Director. The plan must be reviewed and revised by the ow ner or operator, and submitted to the Director for approval, at the same frequency and time as the AOR reevaluation. The requirement to maintain and implem ent an approved plan is directly enforceable regardless of whether the requi rement is a condition of the permit. The well plugging plan must be submitted as part of the permit application and must include the foll owing information:

Response: EPA agrees that developing, maintaining, and implementing an injection well plugging plan is important to assuring that GS we lls are plugged in a manner that will ensure that the well will not serve as a conduit for CO2 leakage preventing endangerment of USDWs.

EPA disagrees with the suggested change, however. The final rule requirement at §146.92(c) for the owner or operator to notify the Dir ector of any changes to the injection well plugging plan at least 60 days before plugging the well will allow the owner or operator (through communication with the Director) to address any issues associated with the initial well plugging plan s ubmitted with the permit application. EPA is not requiring fo rmal periodic review and updates to the injection well plugging plan throughout the injection phase. EPA does not expect that changes to this plan would be implemented until injection operations cease. EPA envisions that owners or operators will take into account similar considerations that guide updates to other project plans, e.g., monitoring and operational data and results of AoR reevaluations.

EPA clarifies that the owner or operator's injection well plugging plan will be incorporated as a condition of their UIC permit and is therefore enforceable; failure to follow the approved plan would be considered a violation of th e permit and would be subject to applicable civil, cr iminal, or administrative
p enalties under §1423 of the SDWA. Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23747Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: Part 146.93(a) As previously stated AWWA be lieves that potential changes in the size of the area of review require that all site plan s be reevaluated at the same frequency as the area of review. Ther efore, AWWA recommends revising this
p art to read:

The owner or operator of a Class VI well must prepare, maintain, and comply with a plan for post-injection site care and si te closure that meet s the requirements of paragraph (a)(2) of this section and is acceptable to the Director. The plan must be reviewed and revised by the ow ner or operator, and submitted to the Director for approval, at the same frequency and time as the AOR reevaluation.

Response: As described above, the final rule requires review and revision of the post-injection and site care closure plan when injection ceases, as desc ribed in §146.93(a)(3). EPA is not requiring formal
p eriodic review and updates to the PISC and site closure plan throughout the injection phase. EPA does not expect that changes to this pl an would be implemented until inje ction operations cease. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Part 146.93(b)(3) When addressi ng plume stabilization in association with site closure, it is important to realize that the carbon dioxide plume will never be completely stable. The carbon dioxide plume will continue to move by a combination of methods in cluding density differences, natural formation flow gradients and diffusion. AWWA recommends that EPA engage in research to provide specific criteria on what exactly it would mean for the plume to have stabilized. If left up to the discretion of the various Director s, stabilization could be defined in many different ways . In order to have a consistent application of this part of the regul ation, EPA should define the specific situations in which the plume could be considered "stable." AWWA recommends revising this part to read:

Prior to authorization for site closure, the owner or operator must demonstrate to the Director, based on monitoring and other site-s pecific data that no additional monitoring is needed to a ssure that the geologic sequestration
p roject does not pose an endangerment to USDWs. The demonstration must demonstrate all of the following:

(i) the estimated magnitude and extent of the project footprin t (CO2 plume and the area of elevated pressure) ba sed on measurements and modeling; (ii) that CO2 movement and pressure changes match model predictions, (iii) the estimated location of the det ectable CO2 plume based on measurement and modeling (measuring magnitude of satu ration within the plume or mapping the edge of it); (iv) that there is no evidence of significan t leakage of either CO2 or displaced formation fluids that endan g er USDWs; Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23748

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23749(v) that the CO2 plume and displaced formation fluid are not expected to migrate in the future in a manner that enc ounters a potential leakage pathway; (vi) that the injection wells at the site completed into or through the injection zone or confining zone are properly plugged and abandoned; and, (vii) any remaining project monitoring well s at the site are being managed by a
p erson and in a manner acceptable to the Director.

Response: EPA acknowledges that many site-s pecific factors will influence the determination of when the CO2 plume and pressure front no longer pose a risk of endangerment to USDWs. It is for this reason that EPA believes that i ndividual UIC Directors, in consultation with operators, will be in the best
p osition to determine whether additional post-injection site care is needed. EPA expects this decision to be made based on relevant site data and in cons ultation with all potentially impacted parties.

EPA agrees that a complete cessa tion of plume movement may not oc cur at some sites for long time
p eriods due to density diff erences, natural formation flow gradients and diffusion. EPA clarifies that a complete cessation of plume movement is not re quired, only a demonstration that the plume and
p ressure front no longer pose a risk of endangerment to USDWs.

EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and m onitoring wells; perform post-inj ection monitoring; demonstrate non endangerment; and perform site closure activities. The guida nce will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: Part 146.94(a) It is important that the emergency and remedial response plan is reviewed and updated on th e same schedule as the area of review update. Changes in the area of review could affect the actions that would need to be taken in the event of an emergency. AWWA recomm ends revising this part to read:

As part of the permit application, th e owner or operator must provide the Director with an emergency and remedial response plan that describes actions to be taken to address movement of the inject ion or formation fluids that may cause an endangerment to a USDW during cons truction, operation, closure and postclosure periods. The emergency and remedial response plan must be reviewed and updated, as necessary, on the same schedule as the update to the Area of Review.

Response: EPA has added a requirement at §146.94(d) that owners or ope rators must review their emergency and remedial response plan within one year of an AoR reevaluation required under §146.84 or following significant changes to the facility. Subsequently, owners or operators must submit an amended plan or demonstrate to the Director that no amendment to th e plan is needed based on the AoR reevaluation or any significant ch anges made to the facility. Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23751Other EPA Comment Codes and Descriptions: 4660 2.6.6 Geochemical monitoring Comment: Part 146.90(d) AWWA recommends revising this part to read:

Periodic monitoring of the ground water quali ty and geochemical changes within (if wells can be installed without adve rsely affecting the integrity of the confining zone) and above the confining z one(s) that may be a result of carbon dioxide movement through the confining z one or additional identified zones:

Response: EPA clarifies that §146.90(d) requires geochemical monitoring above the confining zone. To mitigate the risk of fluid movement, EPA require s owners and operators to submit a testing and monitoring plan that describes how the owner or operator plans to site and construct monitoring wells.

EPA believes that monitoring using wells in the injection zone, e.g., for pressure monitoring as required at §146.90(g)(1), can be safely performed if the we lls are constructed to prevent flow between the injection zone and USDWs or other layers above the confining zone. Such construction technologies exist and have been used in the oil and gas industry for years. EPA believes that properly constructed monitoring wells will be a safe way to obtain the data that is essential to ensure that the injected CO2 remains confined in the injection z one and that pressure changes are not causing movement of formation or other fluids. To mitigate the risk of fluid move ment, EPA requires owners an d operators to submit a testing and monitoring plan that describes how th e owner or operator plans to site and construct monitoring wells. EPA is developing guidance on well construction that will include recommendations for monitoring well construction. The guidance will be available on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm. EPA is developing guidance on testing and monitoring to assist owners or opera tors and Directors in evaluating requirements under §146.90, in cluding proposed monitoring pl ans. The guidance describes available technologies and recommended approaches for implementing a test ing and monitoring plan, including pre-operational geophys ical logging and test ing of injection wells, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: Part 146.90(d)(1) AWWA recommends revising this part to read:

The location and number of monitoring we lls must be based on specific information about the geol ogic sequestration project, including injection rate and volume, geology, the presence of natu ral discontinuities and artificial
p enetrations and other factors.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has ma de many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

EPA's g uidance on testin g and monitorin g will provide g uidance on monitorin g well placement. The Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 24332

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 24339guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Part 146.92(b)(5) AWWA recommends revising this part to read:

The type and grade and quantity of material to be used in plugging. The material must be compatible with the carbon dioxi de stream and pre-in jection formation conditions; and

Response: EPA believes, considering the pote ntially corrosive nature of CO2 when it is in contact with water, that the requirement that the material must be compatible with the CO2 stream is appropriate. The final rule retains this requirement.

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: Part 146.93(b)(2) AWWA recommends that th ere should be a minimum 50 year postinjection monitoring period for all carbon sequestration projects. This time
p eriod is necessary to monitor the site for changes that may occur over a longer amount of time, such as gradual leakages , or sudden seismic shifts. After this time period, the owner/operator may apply to the Director for a modification or termination of the monitori ng requirements. AWWA recomm ends revising this part to read:

If, after the 50-year post-injection m onitoring period, the owner or operator can demonstrate to the satisfaction of the Director, based on monitoring and other site-specific data, that the ge ologic sequestration project no longer
p oses an endangerment to USDWs, the Dire ctor may approve an amendment to the
p ost-injection site care and site closur e plan to reduce the frequency of monitoring or may authorize site closure before the e nd of the 50-year period.

Response: As described above, EPA agrees with commente rs that a 50 year post-injection site care timeframe represents a reas onable and protective post-injection site monitoring period in most cases and available data, including data subm itted by commenters, do not suppor t a different default timeframe. EPA bases this on a review of re search studies, industry reports, a nd existing environmental programs, and evaluation of public comments. Furthermore, EPA be lieves that a 50-year de fault post-injection site care timeframe is not overly burdensome, does not exaggerate the risks associated with GS, is consistent with other environmental programs, and sufficiently protects USDWs from endangerment. For this reason, the final GS regulation retain s the 50 year post-injection site care timeframe, as specified in §146.93(b)(1).

However, EPA disagrees that a 50 year post-inject ion site care timeframe should be an absolute minimum. Rather, EPA believes, as some commenters suggest, that there will be circumstances where it can be demonstrated in less than 50 y ears that the plume and pressure front no lon g er pose a risk of Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 24371

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 24372endangerment to USDWs. For this reason, the GS rule offers owners or operators flexibility regarding the duration of the PISC timeframe by: (1) allowing th e Director discretion to shorten or lengthen the PISC timeframe during the post-inj ection period based on site-specific data, pursuant to requirements at §146.93(b); or (2) affording the Direct or discretion to allow a Class VI well owner or operator to demonstrate, during the permitting pr ocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangermen t of USDWs pursuant to requirements at §146.93(c).

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe for
p ost-injection site care will be necessary in most cases. The default 50 year post-injection site care timeframe represents a r easonable and protective monitoring peri od based on a review of research studies, industry reports, and exis ting environmental programs, and evaluation of public comments.

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts.

Other EPA Comment Codes and Descriptions: 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Part 146.93(c) AWWA recommends that this part of the rule needs to include a directive that the Director needs to provi de approval for site closure prior to implementation of the site-clo sure plan. AWWA recommends revising this part to read:

N otice of intent for site closure. The owner or operator must notify the Director at least 120 days be fore site closure. At this time, if any changes have been made to the original post-injection site care and site closure plan, the owner or operator must also provide the revised plan. The Director must
p rovide approval for site closure prior to the impl ementation of the site closure plan. At the discretion of the Director, a shorter notice period may be allowed.

Response: EPA considers the combination of the Director's evaluation of the data submitted to support a demonstration of non-endangerment of USDWs, as sp ecified in §146.93(b)(3), and the Director's receipt of and agreement with the notification of intent for site closure as confirmation that GS site closure can
p roceed.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: Part 146.82(d)(3) AWWA recommends revising this part to read:

Information on the seismic history within the proposed area of review including
p resence and depth of seismic sources, knowled g e of previous seismic events and Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 24373

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 24374history of these events, and a determin ation that the seismicity would not interfere with containment.

Response: EPA agrees that consideration of local and regi onal seismicity is important. This information is required for GS projects at §146.82(a)(3)(v). The site characterization provisions in the GS rule also require the owner or operator to submit data on known or suspected faults in the AoR (§146.82(a)(3) (ii)). Beyond the AoR (the specific project area) EP A notes that the site ch aracterization requires a review of the local and regional geology, and detailed review of a ny known or potential seismically active terrain in the vicinity of a proposed GS site would certainly be required in a GS site characterization.

Other EPA Comment Codes and Descriptions: 3420 2.2.2.1 Scope of the inventory process (e.g., reliance on publicly available in formation, depth of wells) Comment: Part 146.84(d) AWWA recommends revising this part to read:

Owners or operators of Cl ass VI wells must perform corrective action on all wells and other artificial penetrations in the ar ea of review that are determined to need corrective action using methods necessary to prevent the movement of fluid into or between USDWs and between the injection zones(s) and USDWs, including use of corrosion resistant materials, where appropriate.

Response: EPA revised the text at §146.84(d) to require the use of materials that are "compatible with the carbon dioxide stream." EPA beli eves this language change addresses commenters' concerns and is also consistent with other language regarding materi als requirements in the GS rule. EPA believes that meeting the requirement for preven ting "movement of fluid into or between USDWs" will prevent movement between the injection zone and USDWs; therefore, it did not make the suggested change.

Other EPA Comment Codes and Descriptions: 3800 2.3 Proposed Injection Well Construction Requirements ( 40 CFR 146.86) Comment: Part 146.86(b)(1)(i) AWWA recommends revising this part to read:

Depth to the injection zone and overbur den pressures in the injection zone.

Response: EPA believes that the requirement in 146.86(b)(i i) to report the external pressure provides the same information as the requested change. Base d on its evaluation of all public comments and input on the proposed rule and NODA and Request for Co mment EPA has made many revisions to the GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: Part 146.83(a)(2) AWWA recommends revising this part to read: Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 24375

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 24376

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 24377A confining zone(s) that is free of tran smissible faults or fractures and of sufficient areal extent and integrity to contain the injected carbon dioxide stream and displaced formation fluids a nd allow injection at proposed maximum
p ressures and volumes without initiati ng or propagating fractures in the injection and confining zone(s).

Response: EPA acknowledges the importance of selecting GS sites with confining zones that are free of transmissive faults a nd fractures but disagrees that the rule s hould prohibit fracturing within the injection zone. EPA believes that, in some circumstances, fracturing is necessary (i.e., in association with an approved for stimulation program to improve wellbore and formation inje ctivity). EPA clarifies that all stimulation for GS must be approved by the Director pursuant to requirements at §146.91.

Other EPA Comment Codes and Descriptions: 2048 1.5.2.4 Oppose Class VI/ Support Class V experimental technology well Comment: Rule Provision: 144.15

Proposed CCS Group Recommendations: 4. Adding §144.15 to read as follows. §144.15 Prohibition of non

- experimental Class V wells for geologic sequestration.

The construction, operation or maintenance of any non

- experimental Class V geologic sequestration well is prohibited.

Basis for CCS Group Comments: This provision should be deleted if EPA does limit Class VI wells to injection below the lowermost USDW in the final rule to allow Directors to selectively authorize GS in areas with USDWs below the injection

zone.

Response: The text at 144.15 is retained in the fina l regulation; the construction, operation or maintenance of any non-experimental Class V GS well is pr ohibited under the final rule. The final rule contains tailored requirements fo r Class VI wells to ensure that GS projects are permitted, sited, constructed, operated, and closed in a manner th at avoids releases of CO2 into USDWs.

Comment: Rule Provision: 144.18

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA's rationale.

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24364

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24365

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24366Other EPA Comment Codes and Descriptions: 5700 2.12 Comments on the proposed duration of Class VI permits (seeking comment) Comment: Rule Provision: 144.36

Proposed CCS Group Recommendations: (a) Perm its for Class I and V wells shall be effective for a fixed term not to exceed 10 years EXCEPT FOR WELLS USED FOR GEOLOGIC SEQUESTRATION. UIC Permits for Class II AND III and VI wells shall be issued EFFECTIVE for a period up to the operating life of the facility. PERMITS FOR CLASS VI WELLS AND FO R OTHER WELLS USED FOR GEOLOGIC SEQUESTRATION OF CO2 STREAMS SHALL BE EFFECTIVE FOR THE PERIOD THROUGH SITE CLOSURE.

Basis for CCS Group Comments: Permits ar e necessary for geologic sequestration wells through the end of the post closure monitoring phase, which is consistent with the term site closure in the amended requirement.

Response: EPA clarifies that the final GS rule specifies that Class VI permits wi ll be issued for the operating life of the facility a nd the post-injection site care period (144.36(a)). EPA believes that including the phrase "other well s used for geologic sequestration of CO2 streams" is unnecessary, because all wells used to inject CO2 for the purpose of GS will be classified as Class VI wells. See also discussion in the preamble on grandfathered experime ntal Class V wells and tr ansitioning Class II to Class VI wells.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 144.51(q)(1)

Proposed CCS Group Recommendations: (q) (1) The owner or operator of a Class I, II, III or VI well permitted under this part shall establish mechanical integrity prior to commencing injecti on or on a schedule determined by the Director. Thereafter the owner or operato r of Class I, II, and III wells must maintain mechanical integrity as defined in §146.8 and the owner or operator of Class VI wells must mainta in mechanical integrity as defined in §146.89 of this chapter.

Basis for CCS Group Comments: EPA may want to reconsider the use of the term "or" as this implies that an initial MIT can be optional based on Directors discretion which contradi cts 146.89 with respect to Class VI wells. Alternatively, the two provisions can be read together to require an initial MIT and to give the Director limited discretion to allow the scheduling of the initial MIT after some injection has occu rred, such as may be required during initial testing of the we ll and injection zone.

Response: EPA disagrees that the suggested edit is neede d, and clarifies that all owners or operators must demonstrate internal and exte rnal mechanical integrity prior to commencing injection as required at §146.87(a)(4). Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24369Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Rule Provision: 144.39

Proposed CCS Group Recommendations: TH ESE SECTIONS MAY REQUIRE FURTHER REVISIONS TO PROVIDE CONFORMING LANGUAGE.

Basis for CCS Group Comments: The multi-stakeholder group has agreed that
p roposed language describing wells in cl assification (b)(4) establishes a "bright line" definition for wells that inject CO2 for EOR/EGR and GS and, consistent with EPA’s intent, should remain in Class II and be subject to the current requirements of Class II. We have also agreed that the wells used for GS in oil and gas reser voirs that do not meet the cr iteria of (b)(4) should be subject to additional requirements. We have tentatively defined such wells as wells used "for geologic sequestration in oil and gas formations and where the criteria of paragraph (b)(4) are not me t." But we have not yet attempted to define what specific requirements should a pply to these wells. We are committed to working toward agreemen t on those requirements (probably within a Class II context) and submitting the results of that effort to EPA by February 28, 2009 for your consideration.

In addition, we recommend that all GS into basalts, coal seams, and salt domes be conducted under Class V as experime ntal wells initially and then as commercial scale Class V wells/projects if the experimental pr ojects demonstrate that these sites can be suitable for geological sequestrati on while preventing endangerment of USDWs.

Response: As described above, EPA agrees that injecti on of CO2 for the primary purpose of enhancing oil and gas recovery should remain under the Class II Program. However, the Agency disagrees that wells injecting CO2 for the primar y purpose of long-term storage should be regulated under Class II requirements. EPA recognizes that the oil and gas industry has deca des of experience injecting CO2 for the purpose of EOR, and that sites used for EOR may be suitable for GS and may be among the first GS sites. EPA also recognizes that a by-product of EOR acti vities is that a certain percentage of the CO2 is trapped in the receiving formation.

The Agency believes that the nature and risks of CO2 injection for the pr imary purpose of long-term storage pose different risks than injection for the primary purpose of ER, and therefore has developed new Class VI regulations to address these unique risk s. For example, the volum e of CO2 anticipated to be injected for long-term storage is significantly greater than for EOR operations. Reservoir pressure conditions will also be different, with Class VI injection operations involving large volumes of CO2 and likely having higher pressures wi thin their storage formations than Class II EOR projects.

As described above, EPA clarifies that the GS rule does not categorically preclude injection of CO2 into any non-USDW formation types. If an owner or operator can demonstrat e to the Director's satisfaction that GS in coal seams, basalts, salt domes, or shales can be acc omplished in a manner that protects USDWs and meets all of the requirements of the GS rule, the project may be permitted as a Class VI well. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24370The Agency anticipates that, in the nea r -term, most GS in unmineable coal seams will continue to be experimental. Such projects may be permitted as Class V experimental technology wells if they are of an experimental nature (i.e., to test GS technologies and collect data). EP A will continue to review data on early GS projects, including those in unmineable co al seams, to determine whether the appropriate amount and types of information a nd documentation are required and be ing collected. EPA plans, every six years, to collect a nd review data on GS proj ects to determine whether the appropriate amount and types of information and appropr iate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

Other EPA Comment Codes and Descriptions: 5900 2.14 Other administrative requirements under 40 CFR 144 Comment: Rule Provision: 144.52

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 5900 2.14 Other administrative requirements under 40 CFR 144 Comment: Rule Provision: 144.55

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Rule Provision: 144.80

Proposed CCS Group Recommendations: (b) Clas s II. Classification of Wells: (b) Class II. Wells which inject fluids:.......(2) for enhanced recovery of oil or natural gas; (3) For stor age of hydrocarbons.... and

(4) FOR ENHANCED RECOVERY OF OI L OR NATURAL GAS WHERE GEOLOGIC Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24378

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24379

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24380SEQUESTRATION IS OCCURRING DURING OR IN CONNECTION WITH ENHANCED RECOVERY OF OIL OR N ATURAL GAS PROVIDED (I) THERE IS REASONABLE EXPECT ATION OF MORE THAN INSIGNIFICANT FUTURE PRODUCTION VOLUMES OR RATES AS A RE SULT OF CARBON DIOXIDE INJECTION AND (II) OPERATING PRESSURES ARE NO HIGHER TH AN REASONABLY NECESSARY TO PRODUCE SUCH VOLUMES OR RATES;

Basis for CCS Group Comments: EPA’s Propos al would continue to regulate and
p ermit injection of CO2 for EOR/EGR purposes as Class II inject ion "as long as any production is occurring." EPA has aske d for comment on the merits of this approach "since owners or operators of so me Class II EOR/EGR wells may wish to use wells for the purposes of production and GS prior to the field being completely depleted." 73 Fed. Reg. at 43502. We recommend that the rules be clarified to provide more certainty a bout the applicability of Class II requirements where GS of CO2 occurs in connection with EOR/EGR activities. Specifically, the UIC rules should provide a "bright line" definition as to the applicable class of wells where CO2 inj ection for EOR/EGR production and for GS occur in tandem.

The proposed language describing wells in classification (b)(4) establishes a "bright line" definition for wells that inject CO2 for EOR/EGR and GS and, consistent with EPA’s intent, should remain in Class II and be subject to the current requirements of Class II. We have also agreed that the wells used for GS in oil and gas reser voirs that do not meet the cr iteria of (b)(4) should be subject to additional requirements.

This is the same recommendation as pres ented by the multi-stakeholder group, in which the Carbon Sequestration Council participated.

Response: As described above regarding the suggested edit at 144.6, EPA did not make the suggested change to 144.80. The Agency disagrees that wells in jecting CO2 for the primary purpose of long-term storage should be regulated unde r Class II requirements.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisi ons to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tran sitioning from Class II to Class VI.

Comment: Rule Provision: 144.80(e)

Proposed CCS Group Recommendations : Support the proposed language.

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24381Other EPA Comment Codes and Descriptions: 5900 2.14 Other administrative requirements under 40 CFR 144 Comment: Rule Provision: Part 146 (12)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Rule Provision: 146.5(f)

Proposed CCS Group Recommendations: (b) Clas s II. Classification of Wells: (b) Class II. Wells which inject fluids:.......(2) for enhanced recovery of oil or natural gas; (3) For stor age of hydrocarbons..... and

(4) FOR ENHANCED RECOVERY OF OI L OR NATURAL GAS WHERE GEOLOGIC SEQUESTRATION IS OCCURRING DURING OR IN CONNECTION WITH ENHANCED RECOVERY OF OIL OR N ATURAL GAS PROVIDED (I) THERE IS REASONABLE EXPECT ATION OF MORE THAN INSIGNIFICANT FUTURE PRODUCTION VOLUMES OR RATES AS A RE SULT OF CARBON DIOXIDE INJECTION AND (II) OPERATING PRESSURES ARE NO HIGHER TH AN REASONABLY NECESSARY TO PRODUCE SUCH VOLUMES OR RATES;

Basis for CCS Group Comments: EPA’s Propos al would continue to regulate and
p ermit injection of CO2 for EOR/EGR purposes as Class II inject ion "as long as any production is occurring." EPA has aske d for comment on the merits of this approach "since owners or operators of so me Class II EOR/EGR wells may wish to use wells for the purposes of production and GS prior to the field being completely depleted." 73 Fed. Reg. at 43502. We recommend that the rules be clarified to provide more certainty a bout the applicability of Class II requirements where GS of CO2 occurs in connection with EOR/EGR activities. Specifically, the UIC rules should provide a "bright line" definition as to the applicable class of wells where CO2 inj ection for EOR/EGR production and for GS occur in tandem.

The proposed language describing wells in classification (b)(4) establishes a "bri g ht line" definition for wells that in j ect CO2 for EOR/EGR and GS and, Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24387

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24388consistent with EPA’s intent, should rema in in Class II and be subject to the

Response: As described above, EPA did not make the s uggested change. The Agency disagrees that wells injecting CO2 for the primar y purpose of long-term storage should be regulated under Class II requirements.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisi ons to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tr ansitioning from Class II to Class VI.

The Agency believes that the nature and risks of CO2 injection for the pr imary purpose of long-term storage pose different risks than injection for the primary purpose of ER, and therefore has developed new Class VI regulations to address these unique risk s. For example, the volum e of CO2 anticipated to be injected for long-term storage is significantly greater than for ER operations. Reservoir pressure conditions will also be different, with Class VI injection operations involving large volumes of CO2 and likely having higher pressures wi thin their storage formations than Class II ER projects.

Other EPA Comment Codes and Descriptions: 5900 2.14 Other administrative requirements under 40 CFR 144 Comment: Rule Provision: 146.5(e)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Comment: Rule Provision: 146, Subpart H, List of Headings

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 2048 1.5.2.4 Oppose Class VI/ Support Class V experimental technology well Comment: Rule Provision: 146.81(b) Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24389

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24394

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24398Proposed CCS Group Recommendati ons: (b) This subpart applies to wells used to inject carbon dioxide EXCLUSIVELY for the purpose of geologic sequestration, i.e., the long-term containment of a gaseous, liquid or supercritical carbon dioxide stream in subsurface geologic formations OTHER THAN OIL OR GAS RESERVOIRS, COAL SEAMS, BASALTS, OR SALT CAVERNS.

Basis for CCS Group Comments: See 144.6 and the note immediately above about the requirement for conforming language.

Deleted "gaseous, liquid or supercritical" because it was added to the definition of CO2 stream.

Response: As described above, EPA expects that, after pr omulgation of the final rule, a limited number of experimental injection projects to test GS technology will continue, e.g., to inform the technology associated with GS into basalts, coal seams, and salt domes. Based on it s evaluation of all public comments and input on the propos ed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 2060 1.5.3 Comments on grandfathering of existing wells (seeking comment) Comment: Rule Provision: 146.81(c)

Proposed CCS Group Recommendations: (c) Th is subpart applies to owners and operators of permit or rule-authorized Cl ass I industrial, Clas s II WHICH HAVE CEASED AND WILL NO LONGER BE USED FOR ENHANCED RECOVERY OF OIL OR N ATURAL GAS, or Class V experimental carbon dioxide in jection projects who seek to apply for a Class VI geologic sequestra tion permit for their well or wells. If the Director determines that USDWs will not be endangered, such wells are exempt, at the Director’s discretion, from the casing and ceme nting requirements at §§ 146.86(b) and 146.87(a)(1) through (3). CLASS VI REQUIREMENTS OF SUBPART H OF THIS PART. WELLS CONS TRUCTED IN ACCORDANCE WITH THE CLASS II REQUIREMENTS OF § 146.22 AND USED IN CO2 SERVICE AND THAT HAVE DEMONSTRATED MIT ARE EXEMPT FROM THE REQUIREMENTS AT §§146.86 AND 146.87.

Basis for CCS Group Comments: For first part, see 144.6 and the note above about the requirement for c onforming language.

Added language for transition of Class II wells to Class VI operations. These wells should be allowed based on their history of sound performance under the Class II program as demonstr ated by MIT results. The language also allows the Director to exercise discretion to ex empt other Class VI requirements.

Response: EPA disagrees that other requirements (e.g., monitoring, operational, a nd AoR requirements) should also be g randfathere d. Followin g re-permittin g of the pro j ect as GS, man y of the unique factors Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24399of GS sites (e.g., increased reservoi r pressures associated with larg e volumes of stored CO2 and the corrosivity of CO2 in the presence of water) will re sult in an increased risk profile, warranting the specific requirements in the final GS rule. Following re-permitting as Class VI we lls, these projects must be subject to the operational, MIT, monitoring, re porting, plugging, and post-injection site care and site closure requirements in the final GS rule. See the di scussion of EPA's final re gulatory approach in the
p reamble to the GS rule for additi onal detail on these requirements.

Comment: Rule Provision: 146.82 [Introductory text]

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Comment: Rule Provision: 146.82(a)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(b)

Proposed CCS Group Recommendations: (b) A SURFACE map showing the PROPOSED LOCATIONS FOR the injection well(s) fo r which a permit is sought and the applicable area of review. Within the area of review, the map must show the number, or name and location of all KNO WN injection wells, producing wells, abandoned wells, plugged wells or dry holes, deep stratigraphic boreholes, State or EPA approved subsurface cleanup sites, surface bodies of water, springs, mines (surface and subsurface), quarri es, water wells and other pertinent surface features including structures in tended for human occupancy and roads. The map should also show faults, if known or suspected. Only information of
p ublic record is required to be included on this map;

Basis for CCS Group Comments: Faults are not shown on maps unless there is a Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24411

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24412

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24413surface expression of the fault. Also, faul ts are detailed in (d) below and this language appears redundant.

The word "known" needs to be added to re move any implication that an applicant has to conduct studies to determine the lo cation of wells that are not currently documented in some fashion.

Response: EPA disagrees that information submitted with Class VI pe rmit applications should be limited to known (i.e., previously avai lable) data. Site-speci fic conditions may affect the suitability of a
p roposed site. Therefore the owner or operator must provide to the Director the necessary preliminary information to support a permit decision.

EPA did not delete “faults” from §146.82(b) because faults may have surface expr essions, which should be presented on submitted maps in order to complement the required cross-section data. EPA is developing guidance on site characteri zation for GS projects to assist owners or operators and Directors in evaluating permit requirements and applicati ons under §146.82. The guidance provides recommendations regarding charac terizing the regional geology and hydr ogeology of a proposed GS site as well as performing the necessary geochemical, geomechanical, and geophys ical analyses of the injection and confining zone. The guida nce can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm. Please see the final rule and the discussion of geologic site ch aracterization in the preamble for additional information.

EPA believes that a determination about whether or what information may be necessary (for a specific GS project) is outside of the public record will be site-specific and based on knowledge of the site, data availability, and data quality. For instance, in meeting the requirement to tabulate information on wells in the AoR, the Director has the di scretion to require the owner or ope rator to supplement a data records search if there is reason to believe that the incomp leteness of available information could compromise USDW protection from endangerment. EPA acknowledges that some smaller fractures may not be detectable during the site characterization process, and clarifie s that §146.82(a)(3)(ii) requires the owner or operator to submit data on known or suspected faults and fractu res (i.e., not all fractures).

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(c)

Proposed CCS Group Recommendations: (c) A MAP DELINEATING the area of review based on UPON modeling, using ALL AVAILAB LE data INCLUDING DATA obtained during logging and testing of the well and the formation as required by
p aragraphs (l), (r), and (s) of this section ANY WELLS IN THE AREA OF REVIEW

Basis for CCS Group Comments: This appears to be related to a condition where a well is already drilled. This does not align with requesting information to receive a permit.

Response: EPA agrees that not all of the information li sted at §146.82 of the proposed regulation will be available at the time the owner or operator develops their initial permit a pplication. In response to comments and based on an evaluation of the proposed requirements at §146.82, the A g enc y revised this Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24414subpart so that the final regulation specifies separate requirements for information to be submitted with the permit application and before well construc tion is approved (at §146.82(a)) and information to be submitted before operation of the we ll is authorized (at §146.82(c)).

EPA believes that this revision of §146.82 addresse s commenters' concerns regarding the timing of information to be submitted. In addition, section §146.82 in the final rule is similar to the permit application requirements for other in jection well classes, which could help avoid confusion about how to meet the permitting requirements fo r Class VI wells. The requirements at §146.82(c) for information to be submitted before operation of the well is authorized are very simila r to those for Class I wells, with modifications and additions that a ddress the unique challenges and types of data collected for GS wells.

The requirement to provide the fi nal area of review based on modeli ng and data obtained during logging and testing is in the final GS rule at §146.82(c)(1). Please see the final rule and the discussion of geologic site characterization in the preamble for additional information.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(d)

Proposed CCS Group Recommendations: (d) KNOWN information on the geologic structure and hydrogeologic RESERVOIR properties of the proposed storage site and overlying formations, including:

(1) ISOPACH maps and OF THE PROPOSED INJECTION AND CONFINING ZONE(S), A STRUCTURAL CONTOUR MAP HUNG ON THE TOP OF THE PROPOSED INJECTION ZONE, AND AT LEAST TWO GEOLOGIC cross sect ions of the area of revi ew SHOWING THE GEOLOGIC FORMATIONS FROM THE SURFACE TO TOTAL DEPTH.

(2) Location, orientation, a nd properties of known or suspected SUBSURFACE faults and fractures that may transect the confin ing zone(s) in the area of review and a determination that they w ould not interfere with containment;

Basis for CCS Group Comments: If the information is not known, it cannot be reported.

"Reservoir" and changes to (1) a nd (2) are technical corrections.

Fractures generally can't be identified until a well is dril led and evaluated. Even then, only fractures in the immediat e vicinity of the well bore can be identified.

Response: EPA acknowledges that some sm aller fractures may not be detectable during the site characterization process, and clarifies that §146.82(a)(3)(ii) requi res the owner or operator to submit data on known or suspected faults and fractures (i.e ., not all fractures). Ot her requirements for GS injection wells and sites can mitigate the potential impacts of unidentified fractures. These include limitations on in j ection pressures to avoid propa g ation of existin g fractures in the confinin g zone Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24415(§146.88(a)), collection and assessments of CO2 monitoring data at the site, and Ao R reevaluations (§146.84(e)) to assess possible CO 2 movement through high-permeability regions (i.e., faults and/or fractures) not detected in the initial site characterization.

As described above, EPA disagrees th at information submitted with Cl ass VI permit appl ications should be limited to known (i.e., previously available) data. Site-specific conditi ons may affect the suitability of a proposed site. Therefore the owner or operator must provide to the Di rector the necessary preliminary information to support a permit deci sion. Please see the final rule a nd the discussion of geologic site characterization in the preamble for additional information.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(d)(3)

Proposed CCS Group Recommendations: (3) Info rmation on seismic history THAT HAVE AFFECTED THE PROPOSED AREA OF REVIEW, INCLUDING KNOWLEDGE OF PREVIOUS SEISMIC EVENTS, including the presence and depth of seismic sour ces and a determination that the seismicity would not interfere with containment;

Basis for CCS Group Comments: Information on seismic history should have some degree of relevance to the project.

Response: EPA believes that consideration of local and regi onal seismicity is important and this type of review is relevant to every proj ect. The site characterization provisions in the GS rule, including a review of the local and regional geology, and detailed review of a ny known or potential seismically active terrain in the vicinity of a proposed GS site, are necessary to minimize the potential for induced seismic events or the reactivation of faults, wh ich are a known potential risk associated with underground injection and are addressed in all aspects of the UIC regulations.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(d)(4)

Proposed CCS Group Recommendations: (4) Da ta SUFFICIENT TO DEMONSTRATE THE EFFECTIVENESS OF THE INJECTION AND C ONFINING ZONE(S), INCLUDING DATA ON THE DEPTH, AREAL EXTENT, THICKNESS, MINERALOGY, POROSITY, VERTICAL PERMEABILITY RESERVOIR PRESSURE AND OF THE INJECTION AND C ONFINING ZONE(S ) WITHIN THE AREA OF REVIEW; INCLUDING GEOLOGIC CHANGES BASED ON FIELD DATA WHICH MAY INCLUDE Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24416

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24417GEOLOGIC CORES, OUTCROP DATA, SEIS MIC SURVEYS, WELL LOGS, CAPILLARY PRESSURE TESTS AND NAMES and lith ologic descriptions;

Basis for CCS Group Comments: Capillary pres sure is too hard to measure outside the lab; how comparable are lab results to what goes into the ground. Sidewall core may not be sufficient to do this, and it is difficult to core the whole of the confining and injection zones. Rewording keeps the usefulness of capillary
p ressure in the provision without making it a mandatory use.

Response: EPA acknowledges that laboratory methods are standard for dete rmining capillary pressures regardless of formation permeabilit y and that in situ measurements would require drilling of a well. However, EPA also anticipates that test wells will be drilled to suppor t geologic site characterization of the proposed GS sites and can be used to collect subsurface samples (for la boratory determination of capillary pressure) and take ot her necessary measurements.

EPA recognizes that this information may not be available until after a well has been drilled. EPA revised §146.82 so that the final regulation specifie s separate requirements for information to be submitted with the permit applic ation and before well construc tion is approved (at §146.82(a)) and information to be submitted before operation of the well is authori zed (at §146.82(c)). Final information on injection zone pressures would be required following drilling of the well, at §146.82(c)(4).

EPA believes that information on ca pillary entry pressure is necessary and appropriate. Capillary entry
p ressure measurements on core samples can quantify the amount of buoyant force the confining zone can maintain before failure (Wor ld Resources Institute, 2008).

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(d)(5)

Proposed CCS Group Recommendations: (5) KNOWN geomechanical information on fractures, stress, ductility, rock strengt h, and in situ flui d pressures within the confining zone(s) WITHIN THE AREA OF REVIEW; and

Basis for CCS Group Comments: Clarification.

Rule Provision: 146.82(d)(6)

Proposed CCS Group Recommendati ons: Delete item 6 because this issue is covered under other sections such as (b).

Response: EPA acknowledges the comment but did not make the suggested edits. The Agency believes that the site characterizati on requirements at §146.82, including geomechanical information and geologic and topographic maps and cross sections, are essential to proper siting of a GS well and are the foundation for a detailed understanding of the local and regional geology, and that the owner or operator should collect this information, regardless of whet her it is known in advanc e of the siting process. Collectin g and evaluatin g this data supports important evaluations re g ardin g the suitabilit y of the site to Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24418receive and contain injected CO2.

EPA recognizes that this information may not be available until after a well has been drilled. EPA revised §146.82 so that the final regulation specifie s separate requirements for information to be submitted with the permit applic ation and before well construc tion is approved (at §146.82(a)) and information to be submitted before operation of the well is authori zed (at §146.82(c)). Final information on injection zone pressures would be required following drilling of the well, at §146.82(c)(4).

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(e)

Proposed CCS Group Recomme ndations: (e) A tabulation RECORD of all wells ARTIFICIAL PENETRATIONS within th e area of review which penetrate THAT REACH the injection or confining zone(s). Such data AS AVAILABLE IN THE PUBLIC RECORD must include a desc ription of each well ’ s PENETRATION’S type, construction, date drilled, location, depth, record of plugging and/ or completion, and any additional information the Director may require;

Basis for CCS Group Comments: "Artificial penetrations" is a more inclusive
term.

Rule Provision: 146.82(f)

Proposed CCS Group Recommenda tions: (f) Maps and stratigraphic cross sections indicating the general vertic al and lateral limits of all USDWs, water wells and springs within the area of review, their positions relative to the injection zone(s) and the direction of water movement, where known; POTENTIOMETRIC (WATER LEVEL) SURFACE MAP( S) OF EXISTING AQUIFERS BEING UTILIZED AS PRIVATE OR PUBLIC WATER SUPPLIES AND THE DIRECT ION OF GROUNDWATE R FLOW IN THESE AQUIFERS WITHIN THE AREA OF REVIEW. AT LEAST TWO GEOLOGIC CROSS SECTIONS SHOWING THE THICKNESS AND GENERAL VERTICAL AND LATERAL LIMITS OF ALL USDWS WITHIN THE AREA OF REVIEW.

Basis for CCS Group Comments: This revision more accurately identifies the information that is needed and s hould be considered for permitting.

Rule Provision: 146.82(g)

Proposed CCS Group Recommendations: (g ) Baseline geochemical data on subsurface formations, including al l USDWs in the area of review COMPILATION OF AVAILABLE GEOCHEMICAL DATA ON THE PROPOSED INJECTION ZONE AND N EAREST POROUS AND PERMEABLE FORMATION ABOVE THE CONFINING ZONE. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24419Basis for CCS Group Comments: Limits the data to be submit ted to available information and to the injection zone and the zone immediately above the confining zone which are the zones most li kely to be monitored for potential CO2 leakage.

Response: EPA believes that a determination of what in formation may be necessary for a specific Class VI well and what information is available in the publ ic record will be site-s pecific and based on data availability and data quality. For in stance, in meeting the requirement to tabulate information on wells in the AoR, the Director has the disc retion to require the owner or opera tor to supplement a data records search if there is reason to believe that the incomp leteness of available information could compromise USDW protection from endangerment. Please see the final rule and the discussion of permitting and geologic site characterization in th e preamble for addi tional information.

EPA believes that a thorough unde rstanding of the hydrogeologic conditi ons of all USDWs in the AoR is necessary, and disagr ees with the suggested edits because the GS rule, as written, a ffords flexibility to owners or operators and Directors to tailor the site characterization process to the unique features of the site. EPA encourages owners or operators and Di rectors to collaborate and consult during site characterization to discuss information needs and ensure that all appropriate data to assess the suitability of the site are collected. The Direct or also has the authority to reque st additional hydrogeologic data or other data on USDWs.

The Agency believes that the requirement at §146.82( a)(6) to submit baseli ne geochemical data on subsurface geologic formations, including all USDWs in the AoR, is appropriate and protective of USDWs. EPA believes that this data will support monitoring plan development, inform injectate fate and transport model development (e.g., by providing appropriate input parameters), and provide information needed to respond to any unexpected a nd unpermitted leaks outside of the injection zone. The baseline geochemical informat ion will allow the owner or opera tor and permitting authority to evaluate monitoring data and identify any changes in subsurface geochemistry that may indicate fluid
movement.

The rule requires geochemical analysis of, at a minimum, the injection zone, confining zone, and all USDWs (§146.82(a)(6)). These geochemical tests are necessary to ensure the adequacy of the confining system and to serve as a baseline for future m onitoring. The Director has the discretion to require geochemical analysis of additional subsurface zones if, in the Dir ector's opinion, they are necessary for the protection of USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82); 4710 2.7.1 Propos ed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(h)

Proposed CCS Group Recommendations : (h) Proposed operating data: (1) Average and maximum daily INJECTION rate and volume of the carbon dioxide stream; (2) Average and maximum SURFACE injection pressure;

Clarifications Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24420Basis for CCS Group Comments: Technical clarifications.

Rule Provision: 146.82(i)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Rule Provision: 146.82(j)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Rule Provision: 146.82(k)

Proposed CCS Group Recommendations: (k) Proposed stimulation program and a determination that stimulation will not compromise containment;

Basis for CCS Group Comments: "Interfe re" is too ambiguous and should be replaced by "compromise" whic h limits concerns to situ ations where containment may be lost.

Rule Provision: 146.82(n)

Proposed CCS Group Recommendations: (n ) A WELLBORE schematic or other appropriate drawings of the surface and of the subsurface c onstruction details of the well AND SURFACE WELLHEAD CONSTRUCTION.

Basis for CCS Group Comments: (n) Technical clarification.

Rule Provision: 146.82(q)

Proposed CCS Group Recommendations: (q) The ANY status of corrective action on wells in the area of review;

Basis for CCS Group Comments: Clarifies that wells not needing corrective action will not have a correc tive action status.

Response: EPA acknowledges the commenter’ s support for portions of the subject requirements. EPA disagrees that the suggested technical clarificati ons are necessary. EPA adds that it is developing guidance for owners or operators on the geologic si te characterization and AoR and corrective action
p rocesses. These guidances will provide recommendations and clarify the intent of all required elements of a permit application. The guidan ces can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24421Comment: Rule Provision: 146.83(a) & (a)(1)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment.

Other EPA Comment Codes and Descriptions: 3110 2.1.1 Proposed siting requirements (i.e., injection/confining zones, trapping mechanism) Comment: Rule Provision: 146.83(a)(2)

Proposed CCS Group Recommendations: (2) A confining zone(s) that is LATERALLY CONTINUOUS AND free of KNOWN TRANSECTING, transmissible faults or fractures and of sufficient areal extent and integrit y to contain the injected carbon dioxide stream and displaced formation fluids and allow injection at proposed maximum
p ressures and volumes without initiati ng or propagating fractures in the confining zone(s); and OVER AN AREA SUFFICIENT TO PREVENT THE MOVEMENT OF INJECTED OR DISPLACED FLUIDS INTO A USDW;

Basis for CCS Group Comments: The proposed clarification keeps the emphasis on the non-endangerment of USDWs and limits th e requirements to that which is known or can be readily determined.

Response: The Agency believes that the requirement at §146.83(a)(2) that the confining zone be free of transmissive faults or fractures is appropriate for Class VI well s and is necessary to ensure containment of the injectate and that requiring the confining z one to be free of transmissive faults maximizes
p rotection of USDWs from endangerment. EPA believes that the text regarding propagation of faults and fractures is important to avoid the potential for fluid movement and to ensure that injection is at appropriate pressures. Class I hazardous waste injection well operators must also meet a similar requirement that the site is free of transmissive faults or fractures; they have successfully made such demonstrations in the past. While core samples obt ained through drilling and hydr aulic testing are direct methods to obtain such informati on, geophysical techniques such as seismic or electromagnetic surveys can also be used in many geologic settings to demonstrate the absence of or identify and characterize the
p resence of faults or fractures. EPA adds that the Di rector will evaluate all geologic data on the site to ensure protection of USDWs from endangerment before approving a site for a GS project.

Other EPA Comment Codes and Descriptions: 3120 2.1.2 Need to identify additional confining and containment zones (seeking comment) Comment: Rule Provision: 146.83(b)

Proposed CCS Group Recommenda tions: (b) At the Director ’ s discretion, owners or operators of Class VI wells must id entify and characterize additional zones that will impede vertical fluid movement, are free of faults and fractures that

ma y interfere with containment, allow for pressure dissipation, and provide Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24422

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24423additional opportunities for monitoring, mitigation and remediation.

Basis for CCS Group Comments: This para graph creates a presumption that additional confining zones WILL be requi red. It is also redundant given the
p revious sections. Providing for a confini ng zone that meets the requirements should be sufficient. Any further iden tification of confining zones would
p otentially eliminate zones useful for future geologic sequestration.

Response: EPA clarifies that secondary confining zones are not require d for all GS sites. Rather, secondary confining zones are required when the Director determines that these zones are needed to maximize the protection of USDW s from endangerment. EPA retains the requirement to identify additional containment/confining zones, if required by the Director, as proposed (e.g., §146.83(b)). EPA believes that, in some situations, the presence of additional confining and c ontainment zones above the
p rimary (i.e., lowermost) confining zone can improve USDW pr otection. These laye rs could further impede vertical fluid movement a nd allow for pressure dissipation, and also provide additional sites for monitoring, mitigation, and remediation. The Agency's decision is supported by commenters representing states, water associations, and an electri c utility who assert that these requirements promote a flexible, risk-based, site-specific approach to char acterizing and permitting a si te for GS projects, and are intended to improve understanding of the project as a whole and promote bett er modeling of the site.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(a)

Proposed CCS Group Recommendations: (a) The area of review is the region surrounding the geologic sequestration project that may be impacted by the injection activity. The area of review is based on computational modeling that accounts for the physical and chemical prope rties of all phases of the injected carbon dioxide stream. THE SUBSURFACE THREE-DIMENSIONAL EXTENT OF THE CARBON DIOXIDE PLUME, ASSOCIATED PRESSURE FRONT, AS WELL AS THE OVERLYING FORMATIONS AND SURFACE AREA ABOVE THAT DELINEATED REGION.

Basis for CCS Group Comments: Edits make this provision consistent with the definition of "Area of Review", which was revised.

Response: EPA disagrees that the AoR definition needs to specifically include th e overlying formations and surface area above the delineated region. The intent of the Ao R, a long-standing concept within the UIC Program, is to delineate the surface area and all subsurface formations below it that may potentially be impacted by injection activity. A cceptable delineation models will provide predictions of CO2 fate and transport, as well as changes in formation pressu re, in three dimensions, as a function of time that can be used to delineate the subsurface storage site and the AoR. Although EPA disagrees with the commenter's suggested change, the Agency has carefully considered all comments on the AoR definition at 146.84(a) and modified it to read as follow s: The region surrounding th e geologic sequestration
p roject where USDWs may be endangered by the injection activity. The area of review is delineated using computational modeling that accounts for the physical and chemical properties of all phases of the injected CO2 stream and is based on available site characterization, monitoring, and operational data. EPA believes that this definition is sufficientl y broad and describes both the intent of the computational Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24424modeling and the relationship of the AoR to areas that are subject to the risks as sociated with injection.

Other EPA Comment Codes and Descriptions: 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(b)

Proposed CCS Group Recommendations: (b) The owner or operator of a Class VI well must prepare, maintain, and comply with a plan to delineate the area of review for a proposed geologic seque stration project , periodically reevaluate the delineation, and perform corrective action that meets the requi rements of this section and is IN A MANNER AND AT A FREQUENCY acceptable to the Director. As a
p art of the permit applicati on, for approval by the Director the owner or operator must submit an area of review and corrective action plan that includes the following information:

Basis for CCS Group Comments: Clarification.

Response: EPA disagrees with the suggested change, a nd is retaining the approach of setting a minimum fixed frequency for reevaluating the AoR but has, based on commenters' input, changed the frequency from ten years to at least every five years, as specif ied in §146.84(e). EPA agrees with commenters that site-specific information is an im portant factor in deter mining an appropriate AoR reevaluation frequency, and adds that the owner or operator's AoR and corrective action plan must describe the minimum fixed frequency for reeval uating the AoR and the site-specific conditions on which this frequency is based. EPA adds that the Dire ctor will evaluate the proposed plan in connection with a review of a vast amount of geologic and proposed operating da ta in determining whether to approve the plan. EPA is developing guidance describing recommended approaches to preparing all of the required GS project plans, whic h will address considerations fo r determining an appropriate AoR reevaluation schedule. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment); 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(b)(2)(i) & (ii)

Proposed CCS Group Recommendations: (i) The minimum fixed frequency, not to exceed 10 years, the owner or operato r proposes to reevaluate the area of review; (ii) The monitoring and operati onal conditions that would warrant a reevaluation of the area of review prior to the next scheduled reevaluation as determined by the minimum fixed frequency established in paragraph (b)(2)(i) of this section.

Basis for CCS Group Comments: These provi sions in (i) and (ii) are rendered unnecessary by the revisions to section 146.84(b).

Response: EPA believes that periodic Ao R reevaluation at a set frequenc y of at least ever y five y ears is Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24425

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24426necessary to ensure protection of USDWs from endang erment and address the un certainties inherent in
p redictive modeling. Periodic AoR reevaluations at §146.84(e) ensure that a deliberate effort is made to verify, based on monitoring and operational data, that the CO2 plume is moving within the subsurface as
p redicted. EPA believes that less frequent reevaluations may not be su fficient to appropriately model
p lume and pressure front movement , establish conditions for corrective action, and ensure protection of USDWs from endangerment.

EPA clarifies that if site monitoring data agrees with the existing AoR delineation, a model recalibration may not be necessary, and the AoR reevaluation may consist of a demonstration that the current AoR delineation is adequate base d on site monitoring data.

Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment); 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(b)(2)(iii)

Proposed CCS Group Recommendations: iii (I) How monitori ng and operational data (e.g., injection rate and pressure) wi ll be used to inform an area of review reevaluation; and

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment and the fi nal rule retains this provision.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: Rule Provision: 146.84(b)(2)(iv)

Proposed CCS Group Recommendations: iv (II) How corrective action will be conducted to meet the requirements of pa ragraph (d) of this section, including what corrective action will be performed prior to injection and what, if any,
p ortions of the area of re view will have corrective action addressed on a phased basis and how the phasing will be determ ined; how corrective action will be adjusted if there are changes in the area of review; and how site access will be guaranteed ARRANGED for future corrective action.

Basis for CCS Group Comments: Future access cannot be guaranteed for an area in advance that may not even be within the boundaries of the AOR/ project.

Response: EPA is retaining this requirement as pr oposed. The purpose of the corrective action requirement at §146.84(d) is to ensure that all wells in the AoR that have the potential to cause the movement of CO2 or other fluids into or betw een USDWs receive appropriate corrective action. In general, to meet this re quirement, the owner or operator will most likely need to obtain the right of access to wells that may re quire corrective action, and demonstrate they have done this in their proposed AoR and corrective action plan. In the AoR and co rrective action plan, the owner or operator must describe how site access will be guaranteed for fu ture corrective action as specified in §146.84(b)(2)(iv). Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24427

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24428Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(c)(1)

Proposed CCS Group Recommendations: (1) Pr edict, using computational modeling, the projected lateral and vertical migration of th e carbon dioxide plume and formation fluids in the subsurface from the commencement of injection activities until INJECTION INDUCED plume movement ceases, pressure differentials sufficient to cause the movement of in jected fluids or formation fluids into a USDW are no longer present, or after FOR a fixed time period as determined by the Director. The model MODELING must:

Basis for CCS Group Comments: Clarification

Response: Based on an evaluation of all comments received, EPA has clarified this language in the final rule at 146.84(c)(1). It now reads, “Predict, us ing existing site characterization, monitoring and operational data, and computational modeling, the projected lateral and vertical migration of the carbon dioxide plume and formation fluids in the subsurf ace from the commencement of injection activities until the plume movement ceases, until pressure diff erentials sufficient to cause the movement of injected fluids or formation fluids into a USDW ar e no longer present, or until the end of a fixed time
p eriod as determined by the Director.”

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(c)(1)(i) & (ii)

Proposed CCS Group Recommendations: (i) Be based on detailed geologic data collected AVAILABLE to characterize the in jection zone, confining zone and any additional zones ; and anticipated operating data, including injection
p ressures, rates and total volumes over the proposed life of the geological sequestration project THE DURATION OF INJECTION;

(ii) Take into account any RELEVANT geologic heter ogeneities, AND data quality, and their possible impa ct on model predictions; and

Basis for CCS Group Comments: Allows the use of all available data, not just data collected specifically for this permit.

Response: EPA agrees that detailed geologic data is i nvaluable to modeling an accurate AoR. EPA clarifies that owners or operato rs may use existing data as well as data collected during site characterization to predict the AoR. The final ru le retains the language in §146.84(c)(1)(i) as proposed, and modifies §146.84(c)(1)(ii) slightly to require owners or operators to take into account “other discontinuities” in addition to geologic he terogeneities when predicting the AoR.

EPA disagrees that only the injection and confini ng zones should be included in AoR modeling of GS sites. EPA believes that the modelin g should also take into account the possibilit y of displaced fluids or Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24429

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24430b rines caused by a lateral and/or ve rtical pressure plume, and theref ore it may be necessary to include additional zones along with the confin ing/injection zones to ensure the integrity of the confining zone and ultimately protect a US DW from endangerment.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(c)(1)(iii)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the commenter’ s support; the final GS rule retains the provision in §146.84(c)(1)(iii) as proposed.

Other EPA Comment Codes and Descriptions: 3420 2.2.2.1 Scope of the inventory process (e.g., reliance on publicly available in formation, depth of wells) Comment: Rule Provision: 146.84(c)(2)

Proposed CCS Group Recommendations: (2) Using methods approved by the Director, Identify all KNOWN ARTIFICIAL penetr ations INTO THE CONFINING ZONE AVAILABLE IN THE PUBLIC RECORD, including active and abandoned wells and underground mines, in the area of review that may penetrate REACH the confining zone. Provide a description of each well’s type, construction, date drilled, location, depth, record of plugging and/or completion, and any additional information the Di rector may require; and

Basis for CCS Group Comments: Changed fo r consistency with earlier language.

Response: EPA is retaining the requirement as proposed. EPA agrees with commenters that, for most GS sites, relying on database and ot her public records searches (i.e., of "known" artificial penetrations) will be sufficient to meet the requirements at §146.84(c)(2). However, the Agency recognizes that there may be situations where additional surveys or research to locate wells may be appropriate. For example, there may be cases where the Dire ctor may determine that ground or airborne surveys for wells are appropriate, e.g., if there is reason to believe, based on knowledge of the site or of available data, that the incompleteness of information on known wells co uld compromise USDW protection. In order to
p reserve the Director's discretion to require an operator to supplement a records search, EPA did not make the suggested change.

EPA adds that all corrective act ion must be performed pursuant to the approved AoR and corrective action plan, which affords the Director the discretion to require any additional information needed (including information that is not publ ically available) to ensure that all necessary corrective action is
p erformed. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24431

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24432Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: Rule Provision: 146.84(c)(3)

Proposed CCS Group Recommendations: (3 ) Determine which abandoned wells IDENTIFIED PURSUANT TO 146.84 (C ) (2) in the area of review have been
p lugged (as required by §146.92) in a manner that prevents the movement of carbon dioxide or associated FORMATION fluids that may endanger USDWs.

Basis for CCS Group Comments: Remove "i n the area of review" as redundant.

Response: EPA clarifies that the term "associated flui ds," as proposed in §146.84(c)(3), refers to formation fluids, other injectates, et c., that may be present in the subsurface and affect movement of the CO2 plume and/or pressure front. EPA believes this terminology woul d incorporate any fluids in the subsurface that could potentially move through artificial penetrations and affect USDWs. EPA has revised the language at §146.84(c)(3) to read, "... ca rbon dioxide or other fl uids that may endanger USDWs..." EPA disagrees that deleting the term area of review is necessary and has retained the term in the final rule language.

Other EPA Comment Codes and Descriptions: 3460 2.2.2.3 Acceptable correct ive action techniques for GS sites (e.g., cements) Comment: Rule Provision: 146.84(d)

Proposed CCS Group Recommendati ons: Owners or operators of Class VI wells must
p erform corrective action USING MATERIALS SUITABLE FOR USE WITH THE CARBON DIOXIDE STREAM AND FORM ATION FLUIDS, on all well s in the area of review IDENTIFIED IN 146.84(C)(2) that are dete rmined to need corrective action". using methods necessary to prevent the m ovement of fluid into or between USDWs including use of corros ion resistant material s, where appropriate.

Basis for CCS Group Comments: Experience with CO2 based EOR strongly supports the use of many conventional materials that might not meet the technical definition of "corrosion resistant".

Response: EPA revised the text at §146.84(d) to require the use of materials that are "compatible with the carbon dioxide stream." EPA beli eves this language change addresses commenters' concerns and is also consistent with other language regardi ng materials requirements in the GS rule.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: Rule Provision: 146.84(e)

Proposed CCS Group Recommendations: (e) If monitoring data indicate an endangerment to USDWs, the owner or opera tor must notify the Director and cease operations as required b y § 146.94. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24433

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24434

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24435Basis for CCS Group Comments: This is not needed since §146.94 already specifies the notification and cessation of inject ion. We suggest deletion of this language as unnecessar ily duplicative.

Response: Based on consideration of all public comments and other information, EPA deleted this
p rovision from §146.84. The final rule now contains a provision in §146.91(c) that requires the owner or operator to report within 24 hours any evidence that th e carbon dioxide stream or associated pressure front may cause an endangerment to a USDW. EPA believes this change consolidates reporting requirements in one place and provides additional clarity.

Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment) Comment: Rule Provision: 146.84(f)

Proposed CCS Group Recommenda tions: (f) At the minimum fixed frequency, not to exceed 10 years, as specified in the approved area of revi ew and corrective action plan, or When monitoring and operational conditions warrant, owners or operators must:

Basis for CCS Group Comments: Rather than a fixed time peri od, we recommend following a performance based approach that would be based on significant changes in injection parameters or anomalous monitoring results.

Response: EPA agrees that site-specific factors should be considered in the reevaluation schedule, and notes that the AoR and corrective action plan must specify the site-specific monitoring and operational conditions that warrant reevaluation, as specified in §146.84(b)(2)(ii). In addition, the Director has discretion to require more frequent AoR reevaluation if he or she has reason to believe, based on sitespecific information, that a five-y ear reevaluation schedule is not sufficiently protective of USDWs. However, EPA believes that setting a minimum reevaluation frequency is appropriate. In the final rule, the Agency changed the minimum frequency for the AoR reevaluation at §146.84(e) from ten years to at least every five years in the final GS rule. EPA believes that this revi sed frequency addresses commenters' concerns about the inherent uncertainties in modeling CO2 movement, the emerging nature of GS technology, risk-based targeting of monitoring activities, and the unique nature of CO2 GS.

Other EPA Comment Codes and Descriptions: 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(f)(4)

Proposed CCS Group Recommendati ons: (4) Submit an amended area of review and corrective action plan or demonstrate to the Director through monitoring data and modeling results that no amendment CHANGE to the area of review and corrective action plan is needed.

Basis for CCS Group Comments: Clarification Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24436

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24437Response: EPA disagrees with the suggested change and believes the proposed text is clear as written. For additional information on EPA's approach to AoR and corrective action, please see the final rule and
p reamble.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(g)

Proposed CCS Group Recommendations: (g) The emergency and remedial response plan (as required by § 146.94) and a demonstrat ion of financial responsibility (as described by § 146.85) must account for the en tire area of review AS MODIFIED PURSUANT TO § 146.94(F), regard less of whether or not corrective action in the area of review is phased.

Basis for CCS Group Comments: Need to ad d phrase to account for the periodic reevaluations and possi ble revisions that will be occurring.

Response: EPA agrees with the commenter and has modifi ed the final rule at §146.84(f) to require the emergency and remedial re sponse plan and the demonstration of fi nancial responsibilit y to take into account the most recently evaluated AoR.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Rule Provision: 146.85(a)

Proposed CCS Group Recommendations: (a) The owner or operator must demonstrate and maintain financial responsibility a nd resources for corrective action (that meets the requirements of § 146.84), inj ection well plugging (that meets the requirements of § 146.92), post-injection site care and site cl osure (that meets the requirements of § 146.93), and emergency and remedial response (that meets the requirements of § 146.94) in a manner prescribed by the Director until:

(1) The Director receives WELL PLUGGI NG REPORT IDENTIFIED IN 146.92(D) and
approves OR COMPLETION OF the completed post-injection site care and site closure plan AS APPROPRIATE; and

Basis for CCS Group Comments: Maintena nce of the well plugging financial obligation until site closure is not n ecessary. The Director should have the authority to release the obligation once the well is plugged.

Response: EPA will allow owners or operators to use se parate financial respons ibility instruments for different GS activities. Howeve r, owners or operators must demonstrate adequate financial responsibility for all required activities, including well plugging, with their permit application, per §146.82(a)(14). In addition, on an annual ba sis, the owner or operator must ad j ust the cost estimate for Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24438

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24439inflation, increase or decrease the value of the fina ncial instrument to match the cost estimate, and
p rovide any updated informat ion related to their financial responsib ility instrument(s), or at any other time deemed appropriate by the Director. These annual reviews provide a mechanism for revising cost estimates up or down to account for changes in the project, including the exec ution of environmental obligations as phases of a GS project are completed.

Regarding the suggested edit at §146.85(a)(1), EPA clarifies that the owne r or operator may call upon their financial instrument when the phase of the project for which the instrument was required is complete and all financial obligations for that instrument have been met, as specified in §146.85(b)(2). For example, when the injection we ll is plugged to the Director's satisfaction, the owner or operator's financial instrument will be released if it was not used. See the fi nal rule and preamble for further discussion of EPA's final approach to financial responsibility.

EPA is developing guidance on financial responsibility for GS wells. The guidance will include a discussion on how best to estimate costs to assist Cla ss VI well owners or opera tors, third party insurers or providers of financial instrume nts, and permitting auth orities in developing estimates of the costs associated with various GS activities. Th e guidance is available on EPA's website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Rule Provision: 146.85(b)

Proposed CCS Group Recommendations: (b) The owner or operator mu st provide to the Director, at a frequency determined by the Director, BUT NO MORE FREQUENTLY THAN ANNUALLY, written updates of adjustment s to the cost estimate to account for any amendments CHANGE to the area of review and corrective action plan (§146.84), the injection well plugging plan (§146.92), and the post-injection site care and site closure plan (§146.93).

Basis for CCS Group Comments: Requiring update s more frequently than annually is not justified and less frequent updates should be a ppropriate in many cases.

Response: Cost estimates will need to be reevaluated after amendments to the area of review and corrective action plan, prior to we ll plugging or site closure, after amendments to the emergency and remedial response plan, or at any other time deemed appropriate by the Director. The rule will also require annual adjustments to the cost estimates fo r inflation, as specified in §146.85(c)(2). These annual reviews provide a mechanism for revising cost esti mates up or down to account for changes in the
p roject, including the execution of e nvironmental obligations as phases of a GS project are completed.

EPA did not make the proposed edits at §146.85(b), but did extensively revise and clarify the financial responsibility requirements. See the final GS rule and preamble for additional information on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24440

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24441responsibility requirements (40 CFR 146.85) Comment: Rule Provision: 146.85(c)

Proposed CCS Group Recommendations: (c) Th e owner or operator must notify the Director of adverse financia l conditions such as bankruptcy , that may affect the ability to carry out injection well plugging and post-injection site care and site closure.

Basis for CCS Group Comments: Clarification.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS rule. Please see the final rule and the discussion of financial responsibility in the preamble for additional information.

Other EPA Comment Codes and Descriptions: 5432 2.9.1.1 Need to adjust financial responsibility mechanisms (seeking comment) Comment: Rule Provision: 146.85(d)

Proposed CCS Group Recommendations: (d) The operator must provide an adjustment of the cost estimate to the Director if the Director has reason to believe that original THE MOST RECENT demonstration is no longer adequate to cover the cost of injection well plugging (as re quired by §146.92) and post-injection site care and site closure (as required by §146.93)

Basis for CCS Group Comments: Clarification.

Response: EPA agrees that it is important to periodical ly update cost estimate s that support financial responsibility determinations. EP A clarifies that the GS rule, at §146.85(e), requires the owner or operator to provide annual updates to the cost estima te to account for any amendments to the AoR and corrective action plan, the injection well pluggi ng plan, and the PISC an d site clos ure plan.

Other EPA Comment Codes and Descriptions: 3800 2.3 Proposed Injection Well Construction Requirements ( 40 CFR 146.86) Comment: Rule Provision: 146.86(a)(1)

Proposed CCS Group Recommenda tions: (1) Prevent the movement of fluid into or between USDWs or into any unauthorized zones; CONTAINING ANY CONTAMINANT INTO USDWS, IF THE PRESENCE OF THAT CONTAMINANT MAY CAUSE A VIOLATION OF ANY PRIMARY DRINKING WATER REGULATION UNDER 40 CFR PART 142 OR MAY OTHERWISE ADVERSELY AFFECT THE HEALTH OF PERSONS;

Basis for CCS Group Comments: The proposed changes follow the non-endangerment standard that is the basis of the UIC pro g ram. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24442

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24443Response: EPA disagrees that §146.86 as written does not meet the non-endangerment standard as required under the SDWA. EPA believ es that protection of USDWs from endangerment and prevention of fluid movement between formati ons is paramount and believes th at the language as proposed meets the non-endangerment standard. Appropriately designed and constructed wells are necessary to prevent endangerment to USDWs and maintain integrity of the well throughout the lifetime of a GS project. This is the foundation of the requirements for construction and pre-operational testing of Class VI wells at §§146.86 and 146.87.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revi sions to the GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3860 2.3.3 Well component degradation Comment: Rule Provision: 146.86(b)(1)

Proposed CCS Group Recommendations: (1) Ca sing and cement or other materials used in the construction of each Class VI well must have sufficient structural strength and be designed for the operati ng life of the geologic sequestration
p roject WELL. All well materi als must be compatible SUITABLE FOR USE with the fluids with which the materials may be expected to come into contact and meet or exceed TEST standards OR PRACTI CES developed for such materials by the American Petroleum Institute, ASTM Inte rnational, or comparable standards acceptable to the Director. The casing and cementing program must be designed to
p revent the movement of fluids into or between USDWs. In order to allow the Director to determine and specify casing and cementing requirements, the owner or operator must provide th e following information:

Basis for CCS Group Comments: The life of a geologic sequestra tion project could be different than the life of the well. Class VI well design should be based on the life of the well.

Response: EPA disagrees that the casing, cement, or ot her materials should only be designed for the
p eriod of the injection process, ra ther than the life of the seques tration project. GS projects are anticipated to have long life spans in comparison to other types of deep injection wells. Not only must Class VI wells be able to function sa fely and properly over the lifespan of the GS project, but they must b e constructed such that USDWs remain protecte d after well plugging. The requirements at §146.86 will ensure that the well can maintain integrity thr oughout the proposed life span of the project, including after the injection well is plugged and through the post-injection site care period and beyond. While the risk profile of a GS site will decrease following cessation of inje ction, EPA believes that Class VI wells must be designed to protect USDW s from endangerment for the life of the project. Furthermore, rigorous casing and cementing help ensure that the Class VI well will not serve as a conduit for movement of fluids associated wi th future injection operations.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24444

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24445(seeking comment) Comment: Rule Provision: 146.86(b)(1)(v)

Proposed CCS Group Recommendations: (v) Corrosiveness COMPOSITION of the carbon dioxide stream an d formation fluids;

Basis for CCS Group Comments: There is no method for measurement of "corrosiveness" of a CO2 str eam. The relevant informati on is the composition of the CO2 stream.

Response: EPA clarifies that, although corrosiveness does not have a unit of measure, corrosiveness can be technically measured and desc ribed. Procedures that can identify corrosion (or the absence of corrosion) in a Class VI well provide valuable operational information that the Director needs to determine appropriate standards for the tubing and packer.

Other EPA Comment Codes and Descriptions: 3860 2.3.3 Well component degradation Comment: Rule Provision: 146.86(b)(1)(vi)

Proposed CCS Group Recommendati ons: (vi) Down-hole temper atures AND PRESSURES;

Basis for CCS Group Comments: Technical clarification

Response: EPA clarifies that information on down-hole pressures is require d at §146.86(b)(1)(ii).

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: Rule Provision: 146.86(b)(1)(viii)

Proposed CCS Group Recommendations: (viii) Type or grade of cement AND ADDITIVES; and

Basis for CCS Group Comments: Technical revision

Response: EPA agrees with the suggestion that §146.86(b)(1 )(viii) be revised to also address cement additives. In the final GS rule, the subparagraph read s as follows: "Type or gr ade of cement and cement additives."

Other EPA Comment Codes and Descriptions: 3822 2.3.1.1 Depth of surface casing (seeking comment) Comment: Rule Provision: 146.86(b)(2)

Proposed CCS Group Recomme ndations: (2) Surface casin g must extend throu g h the Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24446

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24447

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24448b ase of the lowermost USDW ABOVE THE IN JECTION ZONE and be cemented to the surface EXCEPT THAT THE DIRECTOR MA Y APPROVE A COMBINATION OF CEMENTED SURFACE CASING AND CEMENTED LONG STRING CASI NG TO ACHIEVE CONTINUOUS CEMENT FROM THE SURFACE THROUGH THE BASE OF THE LOWERMOST USDW ABOVE THE INJECTION ZONE.

Basis for CCS Group Comments: Surface casi ng need not be cemented through the base of the lowermost USDW if a combin ation of cement on the surface casing and long-string casing achieves c ontinuous cement through the base of the lowermost USDW above the injection zone. In some pa rts of the US, USDWs are very deep and this standard may preclude geologic sequest ration at otherwise appropriate sites in these areas.

Response: EPA believes that the regulations allow appr opriate flexibility regarding the surface casing. The GS final rule at §146.86(b)(2) requires that surf ace casing extend through the base of the lowermost USDW and be cemented to the surface through the use of a single or multiple strings of casing and cement. It does not, however, spec ify how cementing would be accomp lished, and gives flexibility to the owner or operator to propose alte rnate methods to provide a sufficient amount of cement to meet the standard that USDWs are protecte d. EPA notes that there are many potential ways to meet the requirement, such as the use of staged cementing.

The Director will evaluate the appropriateness of the owner or operator's proposed well construction
p rocedures based on site-specific information about the injection project, includi ng injection pressures, injection and confining zone lit hology, and information about the carbon dioxide stream as provided in §146.86(b)(1). See the discussion of Clas s VI well construction requirement s in the preamble to the final GS rule for additional informat ion. Additionally, EPA is developi ng guidance on the construction of Class VI wells. This guidance will be available on EP A’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

As described above, EPA recognizes concerns rega rding construction of Class VI wells where the lowermost USDW is very deep. To further address comments on deep injection wells, the final GS rule at §146.95 includes requirements for owne rs or operators that seek a waiver of the injection depth requirements.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: Rule Provision: 146.86(b)(3)

Proposed CCS Group Recommendations: (3) At least one long string casing, using a sufficient number of centralizers SET IN A MANNER SO AS TO CREATE A CEMENT BOND THROUGH THE INJECTION AND CONFIN ING ZONE(S). THE LONG STRING CASING
must extend to the injection zone and must be cemented ISOLATED by circulating cement to the surface in one or more stages. PLACING CEMENT AND/OR OTHER ISOLATION TECHNOLOGIES AS NECESSARY TO PROVIDE ADEQUATE ISOLATION OF THE Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24449INJECTION ZONE AND PROVIDE FOR PROTECTION OF USDWS.

Basis for CCS Group Comments: Cementing of the long string casing to surface is not necessary to protect USDWs, and may have negative consequences. Cement to surface would eliminate the ability to m onitor pressures in this annulus and would limit flexibility of remedial options. As revised, the proposal would allow for application and development of alternative technologies. See API RP90 for description of risk-based approach for managing situations involving annular casing pressure. Industry e xperience with CO2 EOR unde r the Class II program demonstrates the effectiveness of existing cementing procedures.

Response: EPA disagrees with the suggested edits. EPA be lieves that the require ments for long-string casing are appropriate and offer appropriate flexibility: §146.86(b)(3) requires that the long-string casing extend to the injection zone and be cemented by circulating cement to the surface in one or more stages. It does not, however, specify how cementing would be accomplished, and gives fl exibility to the owner or operator to propose altern ate methods to provide a sufficient am ount of cement to meet the standard that USDWs are protected from endangerment, subject to the approva l of the Director.

EPA stresses that protection of US DWs is the primary mission and ma ndate of the UIC program and the
p urpose of all requirements for injection wells. A ny injection activity must be demonstrated to not endanger USDWs, regardless of their depth, and if such non-endangerment cannot be shown, then the activity will not be allowed under UIC requirements or the SDWA.

EPA does not believe that the cementing require ments at §146.86 would prevent monitoring, operation, and remediation of Class VI wells. Cementing of deep wells has been performed successfully in the past by owners or operators of Class I hazardous and Class I municipal waste disposal wells. Some of these wells, which must meet the same cementing and ca sing requirements as Class VI wells, are up to 12,000 feet deep and have been successf ully cemented in a manner that main tains integrity and allows for all required well testing, op eration, and remediation (EPA, 2001). S ee the discussion of Class VI well construction requirements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://wat er.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: Rule Provision: 146.86(b)(4)

Proposed CCS Group Recommendations: (4 ) Circulation of cement may be accomplished by staging. The Director ma y approve an alternative method of cementing in cases where the cement cannot be recirculated to the surface,
p rovided the owner or operator can demonstrate by using logs that the cement does not allow fluid moveme nt behind the well bore.

Basis for CCS Group Comments: Same as above

Response: EPA disagrees that the requirement should be deleted. Section 146.86(b)(4) of the final rule allows alternate methods of staging the cement, at the Director's discretion, provided the owner or operator can demonstrate usin g lo g s that the cement does not allow fl uid movement behind the wellbore. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24450See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements (seeking comment) Comment: Rule Provision: 146.86(b)(5)

Proposed CCS Group Recommenda tions: (5) Cement and ceme nt additives must be compatible SUITABLE FOR USE with the carbo n dioxide stream and formation fluids and of sufficient quality and quantity to maintain integrity over the design OPERATING life of the geologic sequestration project WELL. The integrity and location of the cement shal l be verified using technology capable of evaluating cement quality radially and identifying the location of channels to ensure that USDW s are not endangered.

Basis for CCS Group Comments: Experience wi th CO2 EOR under the Class II program demonstrates the effectiveness of exis ting cementing material s and procedures. Standard API cements have been used in numerous CO2 EOR op erations with no adverse consequences. Refer to the citations within EPA’s proposed rule 73 FR 43532-43533: Carey et al., (2007), Crow et al., (2008), and Meyer, J.P (2007).

Response: EPA recognizes that the oil and gas industry ha s decades of experience injecting CO2 for the
p urpose of enhanced recovery, and that this pract ice has led to the devel opment of many corrosion mitigation measures that would be appropri ate for the design of Class VI wells.

EPA believes that the GS rule provi des flexibility: it does not specify materials to be used; rather, it
p rovides owners or operators with the flexibility to choose, as long as the materials used in Class VI wells are compatible with fluids with which they may come into contact and meet or exceed standards developed for such materials by API or ASTM Intern ational, or comparable standards approved by the Director, as provided at §146.86(b)(1). However, EPA clarifies that each individual component of the well system must be described by the owner or opera tor and will be evaluated by the Director and must meet the requirements of the GS rule.

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3826 2.3.1.3 Packer requirements (seeking comment) Comment: Rule Provision: 146.86(c)(2)(ii)

Proposed CCS Group Recommendations: (ii) Characteristics COMPOSITION of the Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24451

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24452carbon dioxide stream. (chemical content, corrosiveness, temperature, and density);

Basis for CCS Group Comments: There is no method for measurement of "corrosiveness" of a CO2 st ream. The relevant informat ion is the composition, not characteristics, of the CO2 stream. The composition of the CO2 stream is more relevant to the design of a tubing and packer system.

Rule Provision: 146.86(c)(2)(iii) - (v)

Proposed CCS Group Recommendations: (iii) MA XIMUM PROPOSED Injection temperature and pressure; (iv) MAXIMUM PROPOSED Annular pressure; (v) MAXIMUM PROPOSED Injection rate (intermittent or conti nuous) and volume of the carbon dioxide stream;

Basis for CCS Group Comments : Technical corrections.

Response: As written, the text at §146.86(c)(3)(ii) accounts fo r all characteristics of the CO2 that could affect the performance of the tubing and packer , including the chemical content, corrosiveness, temperature, and density. The suggest ed revision to refer to CO2 "composition" would be less precise. EPA clarifies that, although corrosiveness does not have a unit of measure, corrosiveness can be technically measured and described. Procedures that can identify corro sion (or the absence of corrosion) in a Class VI well provide valu able operational information that the Director needs to determine appropriate standards for the tubing and packer.

EPA has revised §146.86(c)(3)(iii) and (iv) to refere nce the maximum proposed injection pressure and maximum proposed annular pressure, respectively. EPA has revised §146.86(c)(3)( v) to read "proposed injection rate (intermittent or c ontinuous), and volume and/or mass of the carbon dioxide stream." EPA believes that reference to the c ontinuous injection rate would be duplicative of the maximum rate. EPA believes that considering the maximum injection and annular pressure would be more protective.

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)

Proposed CCS Group Recommendations: (a) Du ring the drilling and construction of a Class VI injection well, the owner or operator must run appropriate logs, surveys and tests to determine or ve rify the depth, thickness, porosity,
p ermeability, and lithology of, and the salinity of any fo rmation fluids in, all relevant geologic formations to assure EVALUATE conformance with the injection well construc tion requirements under §146.86, and to establish accurate baseline data a g ainst which future measurements ma y be compared. The Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24453owner or operator must submit to the Dire ctor a descriptive report prepared by a knowledgeable log analyst that includes an interpretation of the results of such logs and tests. At a minimum, such logs and tests must include: THE DIRECTOR MAY REQUIRE SUCH LOGS AND TESTS AS MAY BE NEEDED AFTER TAKING INTO ACCOUNT THE AVAILABILITY OF SIMILAR DATA IN TH E AREA OF THE DRILLING SITE, THE CONSTRUCTION PLAN, AND THE NEED FOR ADDITIONAL INFO RMATION THAT MAY ARISE FROM TIME TO TIME AS THE CONSTRUCTION OF THE WELL PROGRESSES AND THESE MAY INCLUDE THE FOLLOWING:

Basis for CCS Group Comments: Obtaining the geologic information will not assure conformance with well construction require ments, just measure or evaluate it.

In well defined areas, these evalua tions are frequently unnecessary. The Director should have discre tion to select the appropriate requirements necessary to obtain sufficient baseli ne data and information. For example, in an area where a number of wells are being drille d, the logging of surface hole yields little useful addi tional information.

In particular, this change would allow the Director to reduce the requirements when multiple wells are installed for a project.

Response: EPA disagrees that the require ments for logs, surveys, and tests are unnecessary. All logs, surveys, and tests listed at §146.87(a) are necessary to verify information about the injection and confining zones and ensure that the well is being drilled and cased as approved, and has mechanical integrity. This information is needed to demonstrate that the well can be operated and tested in a manner that protects USDWs from endange rment. While the tests do provide information on some of the same items, each test provides unique pieces of information that build on each other and allow for interpretations not possible with a single test.

EPA notes that the Director has the discretion at §146.87(a)(5) to a pprove alternative methods that
p rovide equivalent or better information, and th e Director may accept information on cores of the injection and confining zones from nearby wells if the owner or ope rator can demonstrate that such cores are representative of conditi ons at the well in question and co re retrieval is not possible, as specified at §146.87(b). EPA believes that logs a nd tests must be performed on each well drilled regardless of existing information about the area to account for the co mplexity of CO2 injection well construction and the buoyancy of CO2. Existing lithologi c and geologic informati on may lack the details needed for site-specific well design and the geology needed to s upport protection of USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(1)

Proposed CCS Group Recommendations : Support the proposed language. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24454Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment and agrees th at logging and testi ng requirements are appropriate and necessary. The final rule retains th e requirements for deviati on checks at §146.87(a)(1).

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(2)(i)

Proposed CCS Group Recommendations: (i) Resistivity, spontaneous potential, and caliper logs before the cas ing is installed; and

Basis for CCS Group Comments: After a few wells are drilled in an area, these evaluations are frequently unnecessary and yi eld little new information. This is an example of where modification of re quirements based on Director discretion may be appropriate.

Response: As described above, EPA disagrees that the re quirements for logs, surveys, and tests are excessive or duplicative. All logs , surveys, and tests listed at §146.87(a) are necessary to verify information about the injection and c onfining zones and ensure that the well is being drilled and cased as approved, and has mechanical integrity. EPA notes th at the Director has the discretion at §146.87(a)(5) to approve alternative methods that provi de equivalent or better information.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(2)(ii)

Proposed CCS Group Recommendations: (ii) A Cement bond and variable density log, and a temperature log evaluation log(s) after the casing is set and cemented.

Basis for CCS Group Comments: Unusual to r un these logs in a surface hole due to uniformity of shallow geology. This is an example of where Di rector discretion may be appropriate.

The proposed change provides more flexibi lity to select the appropriate log to demonstrate adequate cement bond.

Response: EPA clarifies at §146.87(a)(2)(ii) that owners or operators must perform a cement bond (i.e., cement evaluation) log after the casing is set and cemented.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Lo gg in g and testin g requirements (40 Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24455

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24456

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24457CFR 146.87) Comment: Rule Provision: 146.87(a)(3)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. The final rule retains the requirements for the logs required at §146.87(a)(3).

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(3)(i)

Proposed CCS Group Recommendations: (i) Resistivity, spontaneous potential,
p orosity, caliper, gamma ray, fracture finder logs and any other logs the Director requires BASED ON SITE SPECIFIC CONDITIONS AND RISK-BASED FACTORS for the given geology before the casing is installed; and

Basis for CCS Group Comments: It is acceptable to specify basic logging requirements, however, special logs should not be specified. Any other information from the area sh ould be used instead.

Response: EPA believes that a minimum suite of logs and tests is necessary at all Class VI wells. All logs, surveys, and tests listed at §146.87(a) are necessa ry to verify information about the injection and confining zones and ensure that the well is being drilled and cased as approved and has mechanical integrity.

EPA notes that owners or operators will describe in their permit applications how they will construct and test the well, and will also submit site-specific information about the subs urface geology. The Director will evaluate the proposed logging activities along with site-specific geologic in formation to identify geologic data of interest.

EPA adds that, should alternative methods be shown to provide equivalent or better information or if site-specific conditions and risk f actors dictate that other logs are necessary, the Director has the discretion at §146.87(a)(5) to require further logs a nd tests if necessary and to approve alternative methods that provide equivalent or better information.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(3)(ii)

Proposed CCS Group Recommendations: (ii) A Cement bond and variable density log, and a temperature log EVALUATION LOG(S) after the casing is set and cemented. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24458

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24459Basis for CCS Group Comments: The proposed change provides more flexibility to select the appropriate log to de monstrate adequate cement bond.

Response: EPA clarifies at 146.87(a)(3)(ii) that owners or operators must perform a cement bond (i.e., cement evaluation) log after the casing is set and cemented.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(4)

Proposed CCS Group Recommendati ons: (4) A series of tests TEST(S) designed to demonstrate the internal and external mechanical integrity of injection wells, which may include: (i) A pressure test with liquid or gas; (ii) A tracer survey DIAGNOSTIC TOOLS such as oxygen-activation logging; (iii) A temperature or noise log; AND/OR (iv) A casing inspection log. if required by the Director; and

Basis for CCS Group Comments: Technical and grammatical corrections in (4), (4) (ii) and (4)(iii). In (iv), "if requi red by the Director" is unnecessary.

Response: EPA disagrees that allowing the use of unspe cified "diagnostic tool s" would provide the same amount of information as the requirement to pe rform a tracer survey. The track record for tracer surveys in evaluating mechanical inte grity has been proven over time. The Agency clarifies that a tracer survey is one of the mechanical integrity tests that may be required by the Director or used by the owner or operator.

EPA agrees with the commenter about the wordi ng of the casing inspection log requirement at §146.87 (a)(4) and made the suggested change to improve clarity. In the final regulation, §146.87(a)(iv) does not include the phrase, “if required by the Director.”

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(5)

Proposed CCS Group Recommendations: (5) A ny alternative methods that provide equivalent or better info rmation and that are require d of and/or approved of by the Director.

Basis for CCS Group Comments: We interpre t that (5) applies to 146.87(a) and support as proposed. For deletion, same comment as above in (iv).

Response: EPA retained the language in §146.87(a)(5) as pr oposed, allowing the Director discretion to authorize different methods in th at provision, rather than movin g such authorit y to 146.87(a), as the Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24460

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24461commenter requested. EPA notes that §146.87(a)(5) affords the Dir ector discretion to approve alternative methods that provide equivalent or better information, and the Director may accept information on cores of the injecti on and confining zones from nearby we lls if the owner or operator can demonstrate that such cores are repr esentative of conditions at the well in question and core retrieval is not possible, as specified at §146.87(b).

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(b)

Proposed CCS Group Recommendations: (b) The ow ner or operator must submit to the Director A REPORT DESCRIBING whole cores or sidewall cores REPRESENTATIVE of the injection zone and confin ing system and formation fluid samples from the injection zone(s). The Dire ctor may accept DATA FROM cores AND FLUID SAMPLES from nearby wells if the owner or operat or can demonstrate that core retrieval is not possible and that such cores DATA are representative of conditions at the well IN THE WELLBORE. The Direct or may require the owner or operator to core other formations in the borehole.

Basis for CCS Group Comments: The informat ion required should be sufficient to
p roperly describe the injection and confining zones.

Response: EPA clarifies that it is not the Agency's in tent that physical core s be submitted to the Director. In the final GS rule, EPA has revised the first sentence of §146.87(b) to read as follows: "The owner or operator must take whole cores or sidewall cores of the in jection zone and confining system and formation fluid samples from the injection zone(s), and must submit to the Director a detailed report
p repared by a log analyst that includes: well log an alyses (including well logs), core analyses, and formation fluid sample information...."

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(c)

Proposed CCS Group Recommenda tions: (c) PRIOR TO INJECTION WELL OPERATION,the owner or operator must record PROVIDE REPRESENTATIVE INFORMATION ON the fluid FORMATION temperature, FORMATIO N FLUID pH and conductivity, and reservoir pressure and the static fluid level of the injection zone(s).

Basis for CCS Group Comments: Technical corrections. Reservoir pressure and static fluid level are redundant para meters. The phrase "representative information" prevents the operator from having to do all tests in all wells.

Response: EPA disagrees that "reservoir pressure" and "static fluid le vel" are redundant parameters. Although the static fluid level is equal to the bottom hole pressure, this may not always be identical to the reservoir pressure. Additionall y , measurin g the static fluid level provi des additional assurance that Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24462

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24463the reading is accurate (or, provides the needed information in cases where a good reading is not obtained). In addition, a static flui d level measurement provides inform ation regarding the proximity to USDWs that need protection afforded to them.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(d)

Proposed CCS Group Recommendations: (d) At a minimum, the owner or operator must determine or calculate the following information concerning the injection and confining zone(s): (1) Fracture pres sure; (2) Other physical and chemical characteristics of the injection and c onfining zones; and (3) Physical and chemical characteristics of the form ation fluids in the injection zone.

Basis for CCS Group Comments: With the exception of calculating fracture
p ressure, the requirements of this s ection appear redundant to other requirements of prior sections. The fractur e pressure requirement has been added to section 146.87(e) below. (2) and (3) are too vague.

Response: EPA believes that the requirement to provide information on the injection and confining zones in §146.87(d) is warranted. As described above, the rule provides flexibility to account for the variety of geologic conditions that ma y be encountered at GS sites.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(e)

Proposed CCS Group Recommendations: e (D) Upon completion but Prior to INJECTION WELL operation, the owner or operator must

conduct the following tests to verify hydrogeologic characteristics of the injection zone: (1) A pump test ; or (2) Injectivity tests.

ESTIMATE FRACTURE PRESSURES OF THE INJECTION AND CONFINING ZONES AND INJECTIVITY OF THE INJECTION ZONE. ESTIMATES SH OULD BE BASED ON REPRESENTATIVE HYDROGEOLOGIC AND GEOMECHANICAL CHARACTERISTICS OF THE INJECTION ZONE.

Basis for CCS Group Comments: Allows the us e of information such as leak off tests conducted during the drilling operation.

The results of a pump test (pumping flui d from the well) have no relevance for an injection well. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24464

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24465Deletion of the injectivity test would al low the use of non-destructive methods to calculate fracture pressure.

Response: EPA clarifies that the owner or operator has the optio n of using the pump tests or injectivity tests specified at §146.87(e) depending on which would provide the most valuable information based on site-specific conditions. Further, EPA disagrees that pump tests are irre levant to determining injection zone properties. Depending on the ch aracteristics or depth of knowledge of the confining and injection zone formations, pump tests may be necessary to prove that no hydrau lic connection exists between the injection zone and a USDW.

EPA disagrees that the wording at §146.87(d) would lead the owner or operator to employ destructive testing methods for determination of fracture pressure. The wording "d etermined or calculated" allows for calculations to be performed based on non-destructive methods.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(f)

Proposed CCS Group Recommendations: (f) (e) The owner or operator must
p rovide the Director with the opportunity to witness all logging and testing by this subpart. The owner or operator must s ubmit a schedule of such activities to the Director UPON SPUDDING THE WELL and submit any changes to the schedule 48 HOURS prior to the scheduled test.

Basis for CCS Group Comments: The cha nges reflect the realities of rig scheduling and are fully co nsistent with current Class II requirements and
p ractices.

Response: EPA disagrees that the 30-day notification requirement is unreasonable. Acknowledging the developing nature of CO2 GS, EPA believes that invol vement by the permitting authority in each project will provide much needed field data for assurance of USDW protection from endangerment and will help update and refine the permitting process. Adequate timing of notific ation will ensure the Director's ability to be involved.

Other EPA Comment Codes and Descriptions: 4110 2.4.1.1 Injection pressure limitations Comment: Rule Provision: 146.88(a)

Proposed CCS Group Recommendations: (a) Except during stimulation, the owner or operator must ensure that injection pressure does not exceed 90 percent of the fracture pressure of the injection zone so as to assure that the injection does not initiate new fractures or propaga te existing fractures in the injection zone. In no case may inject ion pressure initiate fra ctures in the confining zone(s) or cause the movement of injecti on or formation fluids that endangers a USDW. THE OWNER OR OPERATOR MUST COMPLY WITH A MAXIMUM INJECTION PRESSURE Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24466

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24467LIMIT APPROVED BY THE DIRECTOR AND SPE CIFIED IN THE PERM IT. IN APPROVING A MAXIMUM INJECTION PRESSURE LIMIT, THE DIRECTOR SHALL CONSIDER THE RESULTS OF WELL TESTS AND, WHERE APPR OPRIATE, GEOMECHANICAL OR OTHER STUDIES THAT ASSESS THE RISKS OF TENSILE FAILURE AND SHEAR FAILURE. THE DIRECTOR SHALL APPROVE LIMITS THAT, WITH A REAS ONABLE DEGREE OF CERTAINTY, WILL AVOID INITIATION OR PROPAGATION OF FRACTURES IN THE CONFIN ING ZONE OR CAUSE OTHERWISE NONTRANSMISSIVE FAULTS TR ANSECTING THE CONFINING ZONE TO BECOME TRANSMISSIVE. IN NO CASE MAY INJECTION PRESSURE CAUSE MO VEMENT OF INJECTION OR FORMATION FLUIDS IN A MANNER PROHIBITED BY 40 CFR PART 144.12(A).

Basis for CCS Group Comments: We are concer ned about three aspe cts of proposed section 146.88(a), governing injection pr essure limitations. First, it "restricts" fractures in the injection z one "except during stimulation" rather than focusing on maintaining the integrity of the confining zone, which is what really matters for protecti ng USDWs. Second, it fails to refer specifically to the full range of potential geomechanical failure modes poten tially posed by operations at a particular site. Third, the type of geomechanical risk that is addressed (initiation or propagation of fractures), is dealt with in a
p otentially arbitrary fashion (the 90% of fracture pressure limit), which may not be appropriate in all cases.

Our recommended language addresses these concerns by focusing on maintaining the integrity of the confining zone and incl uding tensile failure and shear failure as transmissivity concerns. It calls for additional geomechanical studies of tensile failure and shear fa ilure only "where appropriate " because there will be ocations where experience or existing information wi ll provide sufficient evidence to avoid the need for additional studies. The need for conducting additional tests and for determining which tests would be acceptable is left to the Director’s discretion.

This is the same recommendation as pres ented by the multi-stakeholder group, in which the Carbon Sequestration Council participated.

Response: EPA notes that because determination of the in jection pressure limit is based on the fracture
p ressure of the injection zone, the limit is site-specific and not arbitrary. EPA em phasizes that injection
p ressure limits are important to prot ect against fracturing of the confining zone, and that the requirement at §146.88(a) that the pressure in the injection zone not exceed 90 percent of the fracture pressure
p rovides a margin of safety in the well operation and protects US DWs from endange rment. If the Director determines, based on a review of the information collected as pa rt of site characterization, that a lower injection pressure limitation is appropriate in order to prevent endangerment of USDWs, the Director has the authority to set a lower limit in th e operating permit than the limit established in the rule.

EPA notes that during the site charac terization process, owners or opera tors must submit data about the geology of the site, as specified at §146.82(a), including data on known or suspected faults and fractures and geomechanical information on frac tures, stress, ductility, rock strength, and in situ fluid pressureswithin the confining zone. The Director will use these data to determine appropriate limits on injection.

In response to the concern about reopening of faults at lower pressures than 90 percent of fracture
p ressure, EPA believes that the requirement for th e owner or operator to submit data on known or suspected faults and fractures and information on the seismic history of the site will inform the determination of an appropriate pr essure limitation in the permit. Any sites with the potential for reopening or reactivation of faults or unacceptable seismic risk that could otherwise interfere with containment will not be permitted as GS sites.

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators in meeting the requirements of §146.82 a nd to assist directors in eval uating permit applications. The guidance will describe recommended approach es for characterizing the regional geology and hydrogeology of a proposed site and performing th e necessary geochemical, geomechanical, and geophysical analyses of the inject ion and confining zone. EPA is al so developing guidance for primacy agencies that will include recommended approaches for evaluating owner or operator-submitted data in setting permit conditions. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4100 2.4.1 Injection parameters Comment: Rule Provision: 146.88(b)

Proposed CCS Group Recommendations: (b) Inj ection OF THE CO2 STREAM between the outermost casing protecting USDWs a nd the well bore is prohibited.

Basis for CCS Group Comments: Routine inject ion into zones other than the target interval(s) should be prohibited, however, wording of this requirement is not clear as to which interval is being addressed. An absolute prohibition on injection into this annulus may also limit diagnostic or remedial options that could be useful.

Response: EPA retains the provision as propos ed, and clarifies that injection between the casing and the well bore is prohibited. This is consistent with requirements for other injection well classes.

Other EPA Comment Codes and Descriptions: 4100 2.4.1 Injection parameters Comment: Rule Provision: 146.88(c)

Proposed CCS Group Recommendations: (c) Th e owner or operator must fill the annulus between the tubing and the long string casing with a non-corrosive fluid approved by the Director. The owner or operator must maintain a positive
p ressure on the annulus.

Basis for CCS Group Comments: Industry experi ence with the Cla ss II UIC program does not support this requirement as proposed by EPA.

Positive annular pressure that exceeds the operatin g in j ection pressure is not Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24468

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24469necessary because a leak from tubing to annulus does not have the same implications as in a Clas s I hazardous situation.

Response: EPA believes that maintaining an annulus pressure that is highe r than the injection pressure, as required at §146.88(c), will ensure that if there are leaks in the tubing, the annulus fluid will move into the tubing, rather than the inj ectate moving out of the tubing and potentially along the outside of the well. EPA believes this requirement is appropriate for Class VI well s given the potential high volumes and supercritical nature of the CO2 injectate, poten tial geomechanical stresses in the wellbore, and the
p otential for movement of the CO2 in the event of a mechanical integrity loss.

Other EPA Comment Codes and Descriptions: 4100 2.4.1 Injection parameters Comment: Rule Provision: 146.88(d)

Proposed CCS Group Recommendations : Support the proposed language..

Basis for CCS Group Comments: Agree with EPA’s rationale

Response: EPA agrees that maintaining mechanical integr ity is an essential co mponent of protecting USDWs. The final rule retains this provision.

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: Rule Provision: 146.88(e)

Proposed CCS Group Recommendations: (e) The owner or operator must install and use continuous recording devices to monito r: the injection pressure; the rate, volume, and temperature of the carbon dioxide stream and . THE OWNER OR OPERATOR MUST REGULARLY MONITOR the pre ssure on the annulus between the tubing and the long string casing a nd annulus fluid volume and . THE OWNER OR OPERATOR must install and use alarms and automatic down

- hole shut-off systems, designed to alert the operator and shut-in the well when operating
p arameters such as injection rate, inj ection pressure, or other parameters approved by the Director diverge beyond ranges and/or gradients specified in the
p ermit;

Basis for CCS Group Comments: Over-press ure protection is best achieved by ensuring compatibility of the casing/tubi ng material design strength with the surface injection (compression) system . Down-hole shut-in devices are not appropriate for this application. These devices are installed in the tubing string and are typically near the surface of the well. They're intended to seal the tubing in the event of catastrophic fa ilure of the wellhead. These devices would provide little if any protection to USDWs. Is not practic able to install these devices deep within the well (e.g. shortly above the packer). Additionally these devices create a restriction on running other tools like logging tools in the well and therefore could limit an operators abilit y to do required Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24470

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24471monitoring and diagnostic work. Lastly, these devices require periodic testing and maintenance which could require eith er pulling the device by wireline or by
p ulling the entire tubing string depending on the type of device installed. Either of these activities would be disruptive and costly to the overall project operations.

Response: EPA acknowledges that proper de sign of the well, including appropriate materials and emplacement of casing and tubing, is essential to proper operation of the well. Such design, however, does not eliminate the possibility of failure, e.g., due to over-pressurizat ion as suggested by the commenter. EPA believes that a multiple-barrier approach, which includes appropriate well design as required at §146.86, suitable injection pressure limits as required at §146.88(a), and automatic shut-off systems, as required at §146.88(e), is necessary to ensure protection of USDWs from endangerment from the risks associated with CO2 GS.

Landing nipples, which are machined portions of the tubing that allow the seating of components–such as safety valves—at a later time, can be used to de ploy safety valves after the initial well completion. EPA believes, however, that if the shut-off system is not deployed until the failure occurs, CO2 will be free to flow out of the well until the shut-off valve is deployed. Since installing the new shut-off system will require getting the device to the site, setting up a rig, and de ploying the device down the well, a significant amount of time could elapse following an adverse even t before the well is sealed. EPA believes that the risks of uncontrolled CO2 flow are too great to be allowed for such a length of time.

As described above, EPA will not require automati c down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells install automatic surface shut-off devices. The rule afford s Director's discretion to mandate automatic downhole shut-off devices in onshore situations that ma y warrant their use. The rule requires, at §146.88(e) (3), that owners or operators of offshore wells within State territor ial waters install automatic down-hole shut-off systems.

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: Rule Provision: 146.88(f)

Proposed CCS Group Recomme ndations: (f) If an down

- hole automatic shutdown is triggered or a loss of mechanical integrity is discove red, the owner or operator must immediately i nvestigate and identify as expeditiously as possible the cause of the shutoff . If, upon such investigation, the well appears to be lacking mechanical integrity, or if monitoring required under paragraph (e) of this section otherwise indicates that the well may be lacking mechanical integrity, the owner or operator must:

Basis for CCS Group Comments: Revisions ma de here to make this subsection conform with changes to 146.88(e) above.

Response: As described above, EPA will not require au tomatic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24472install automatic surface shut-off devices. The rule affords Director's discretion to mandate automatic down-hole shut-off devices in onshore situations that may warrant their use. The rule requires, at §146.88(e)(3), that owners or operators of offshore well s within State territorial waters install automatic down-hole shut-off systems. Please see the final rule and preamble fo r additional information on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4000 2.4 Proposed Injection Well Operating Requirements ( 40 CFR 146.88) Comment: Rule Provision: 146.88(f)(3)

Proposed CCS Group Recommendations: (3) Noti fy the Director within 24 hours OF DISCOVERY;

Basis for CCS Group Comments: Clarifying re vision to (3) will make compliance feasible for operators.

Response: The final rule text at §146.88(f) now reads, "I f a shutdown (i.e., down-hole or at the surface) is triggered or a loss of mechanical integrity is discovered." Therefore the notice required at §146.88(f) (3) must be provided within 24 hours of an automati c shut-off device being triggered or a loss of mechanical integrity being discovered. EPA believes this provision is necessary to ensure timely response to potential USDW endangerment.

Other EPA Comment Codes and Descriptions: 4500 2.5 Proposed Mechanical Integrity Testing (MIT) Requirements (40 CFR 146.89) Comment: Rule Provision: 146.89(a)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment and the final rule retains the text at 146.89(a) as proposed.

Other EPA Comment Codes and Descriptions: 4520 2.5.1 Continuous internal mechanical integrity monitoring (seeking comment); 4720 2.7.2 Oper ational recordkeeping and reporting Comment: Rule Provision: 146.89(b)

Proposed CCS Group Recommendations: (b) To evaluate the absence of significant leaks under paragraph (a)(1) of this section, owners or operators must, following an initial annulus pressure te st, continuously monitor AND RECORD AT LEAST DAILY, ANNULUS PRESSURE AND VO LUMES OF FLUID ADDED TO OR REMOVED FROM in

j ection pressure, rate, in j ected volumes, and pressure on the annulus Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24473

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24474

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24475b etween the tubing and long stem stri ng casing and annulus fluid volume as specified in §146.88 (e);

Basis for CCS Group Comments: We recomm end continuous monitoring, but do not find continuous recording necessary as Class II requirements have proven sufficient. The alternative of continuous monitoring, which will alert operator to any problems, and daily r ecording to allow for daily check of wells. This is consistent with successful Cl ass II operating experience.

Response: EPA agrees with the commenter regarding the importance of dem onstrating internal mechanical integrity (MI). Class VI injection wells will be equipped with dedicated computer-based continuous pressure monitoring devices, in concert with the shut-off systems required for GS wells, which typically take readings several times per second (i.e., more frequently than daily) and record them electronically in a computer system. 40 CFR §146.91(a)(2) requires that monthly averages of the continuous annulus monitoring be reported on a semiannual basis.

Other EPA Comment Codes and Descriptions: 4540 2.5.2 Proposed external MIT requirements; 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: Rule Provision: 146.89(c)

Proposed CCS Group Recommenda tions:(c) At least once per year, the owner or operator must confirm the absence of significant fluid movement under paragraph (a)(2) of this section USING A METHOD ACCE PTABLE TO THE DIRECTOR (E.G. INCLUDING DIAGNOSTIC SURVEYS SUCH AS OXYGEN-ACTIVATION LOGGING OR TEMPERATURE OR N OISE LOGS). (1) A tracer survey such as oxygen

- activation logging; (2) A temperature or noise log; or (3) A casing inspection log, if required by the Director.

Basis for CCS Group Comments: Revised text supports a performance-based approach and allows the development and use of new technologies as they become available. Cement circulation to the surface is not necessary because having the open annulus above the top of cement allows regular monitoring of annular pressure which could indicate leakage.

We recommend deletion of subsection (3) beca use it would require that the tubing be pulled at significant cost and risk of uncontrolled releases.

Response: EPA believes that the MITs described in 146.89( c) of the rule (an approved tracer log or temperature or noise logs) are eff ective methods to demonstrate extern al MI, provide an important early warning of potential problems in th e injection well system, and repres ent standard techniques that have been used successfully by the dril ling industry and for the UIC Program for decades. The Agency notes that the regulations do provide the Director flexibility at §146.89(e) to approve the use of alternative MIT methods.

EPA agrees that the casing inspection log is not an appropriate test to detect fluid movement behind the casing, but clarifies that it can be used to determine the presence orabsence of corrosion of the longstrin g casin g , and is required if the Director determines that it is necessar y based on site-specific Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24476information. EPA has revised the final GS rule to require that th e frequency of the casing inspection log must be specified in the approved te sting and monitoring plan. See §146.89(d).

Other EPA Comment Codes and Descriptions: 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: Rule Provision: 146.89(d)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Rule Provision: 146.89(e)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Rule Provision: 146.89(f)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comments and the final rule retains the text as proposed.

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Rule Provision: 146.90 [Introductory text]

Proposed CCS Group Recommenda tions: (A) BASED ON A SITE -SPECIFIC ASSESSMENT OF THE POTENTIAL FOR FLUID MOVEMENT FROM THE INJECTION WELL OR INJECTION ZONE, AND ON THE POTENTIAL VALUE OF MONITORING WELLS TO DETECT SUCH MOVEMENT, the

owner or operator of a Class VI well must prepare, maintain, and comply with a testing and monitoring plan to verify that the geologic sequest ration project is operating as permitted and is not endangering USDWs. THE TESTING AND MONITORING PLAN MUST BE SUBMITTED WITH THE PERMIT APPLICATION, FOR DIRECTOR APPROVAL AND INCLUDE A DESCRIPTION OF HOW THE OWNER OR OPERATOR WILL MEET THE REQUIREMENTS OF THIS SECTION;

Basis for CCS Group Comments: Drilling m onitoring wells should be carefully considered since each well introduces a potential pathwa y for fluid movement. In Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24477

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24478addition the cost of adding multiple wells could create a barrier to CCS development, while providing limited information on actual movement of the CO2
stream.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA ha s made many revisions to the GS rule. See the final rule and
p reamble for further discussion on EPA's final approach.

EPA anticipates that the testing and monitoring pl an will address site-sp ecific geologic factors, modeling, and risk-assessment. EPA is developing guidance on how best to develop the various required
p roject plans, including the testing and monitoring plan. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm

EPA believes that monitoring using wells in the injection zone, e.g., for pressure monitoring as required at §146.90(g)(1), can be safely performed if the we lls are constructed to prevent flow between the injection zone and USDWs or other layers above the confining zone. Such construction technologies exist and have been used in the oil and gas industry for years. EPA believes that properly constructed monitoring wells will be a safe way to obtain the data that is essential to ensure that the injected CO2 remains confined in the injection z one and that pressure changes are not causing movement of formation or other fluids. To mitigate the risk of fluid move ment, EPA requires owners an d operators to submit a testing and monitoring plan that describes how th e owner or operator plans to site and construct monitoring wells. EPA is developing guidance on well construction that will include recommendations for monitoring well construction. The guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: Rule Provision: 146.90(a) & (b)

Proposed CCS Group Recommendati ons: (B) THE TESTING AND MO NITORING PLAN MUST, AT A MINIMUM, INCLUDE:

(a) (1) analysis of the carbon dioxide stre am with sufficient frequency to yield data representative of its ch emical and physical characteristics;

(b) (2) Installation and use, except dur ing well workovers as defined in section 146.88(d), of continuous monitoring devices (INCLUDING DIGITAL DEVICES CAPTURING PERIODIC DATA) to monitor injection pressure , rate and volume; AND RECORD AT LEAST DAILY the pressure on the annulus between the tubing and the long strong casing;

(3) A DEMONSTRATION OF EXTERNAL MECHANICAL INTEGRITY PURSUANT TO §146.89 (C) UNTIL THE WELL IS PLUGGED;

(4) MONITORING OF THE PRESSURE BUIL DUP IN THE INJECTION ZONE ANNUALLY, INCLUDING AT A MINIMUM, A SHUT DOWN OF THE WE LL FOR A TIME SUFFICIENT TO CONDUCT A Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24479VALID OBSERVATION OF THE PRESSURE FALL-O FF CURVE AT LEAST ONCE EVERY FIVE YEARS; AND (5) A QUALITY ASSURANCE PLAN FOR ALL TESTING AND MONITORING REQUIREMENTS.

Basis for CCS Group Comments: There is concern regarding what constitutes continuous monitoring. Industry agrees that regular monito ring of the parameters identified by EPA is appropriate. Experi ence with CO2 EOR strongly shows that daily monitoring of most of these paramete rs is adequate (exceptions to this would be on a site-specific basis). R ecording should generally be done on a daily basis and reporting on a semi-annual basis.

Response: EPA believes that continuous pressure monito ring of GS wells, as required at §146.88(e), is important and appropriate because the potentially corrosive nature of CO2 streams in the presence of water makes it critical to immediately identify corro sion-related well mechanical integrity loss. Class VI injection wells must be equippe d with dedicated computer-based continuous pressure monitoring devices (in concert with the Dir ector-approved shut-off systems require d for GS wells), which typically take readings several times per second and record them electronically in a computer system..

EPA believes that a frequency of five years, as specified at §146.90(f) , is an appropriate interval for
p ressure fall-off testing (particularl y given the suite of tests operators will perform on the well and the site). EPA clarifies that the Direct or may require more frequent pressu re fall-off tests at a specific
p roject if necessary, based on site-specific circumstances. Pressure fall-off tests may be conducted in conjunction with other well performance tests (i.e., me chanical integrity testing) to ensure safe and effective operations. All monitoring da ta collected, including information from pressure fall-off tests, will be incorporated in AoR reeval uations at least every five years. EPA disagrees that the rule should
p rovide specifics of the testing to the degree suggested, however.

EPA clarifies that periodic MITs will not be required following plugging of the well.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: Rule Provision: 146.90(c)

Proposed CCS Group Recommendations: (C) WHERE APPROPRIATE, THE TESTING AND MONITORING PLAN SHA LL ALSO INCLUDE:

(1) CONTINUOUS MONITORING FOR PRESSU RE CHANGES IN AN APPROPRIATELY POROUS AND PERMEABLE FORMATION OVERLYIN G THE CONFINING ZONE.;

(2) THE USE OF INDIRECT, GEOPHYSICAL TECHNIQUES TO DETER MINE THE POSITION OF THE CO2 STREAM FRONT, THE WATER QUALITY IN A DESIGNATED FORMATION, OR TO Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24480PROVIDE OTHER SITE SPECIFIC DATA;

(3) PERIODIC MONITORING OF WATER QUAL ITY IN AN APPROPRIATELY POROUS AND PERMEABLE FORMATION OVERLY ING THE INJECTION ZONE;

(4) PERIODIC MONITORING OF WATER QUALITY IN ONE OR MORE USDWS;

c (5) Corrosion monitoring of the we ll materials for loss of mass, thickness, cracking, pitting a nd other signs of corrosion performed and recorded AT LEAST on a quarterly WHICH MAY BE MODIFI ED TO BE LESS FREQUENT AS APPROVED BY THE DIRECTOR BASED ON CONSTRUCTION MATERIALS, OPERATING CONDITIONS, AND MONITORING HISTORY to ensure that the well components meet the minimum standards for material strength and pe rformance set forth in §146.86(b) by:

(1) (I) Placing ANALYZING coupons of the we ll construction materials
p laced in contact with the carbon dioxide stream; or

(2) (II) Routing the carbon dioxide stre am through a loop constructed with the material used in the well AND INSP ECTING THE MATERIALS IN THE LOOP; or

(3) (III) Using an alternative method, MATE RIALS, OR TIME PERIOD approved by the Director;

(6) ANY ADDITIONAL TESTING AND MONITO RING NECESSARY TO SUPPORT MODELING THE EXTENT OF THE CARBON DIOXIDE PLUME AN D THE POSITION OF THE PRESSURE FRONT; AND

(7) ANY ADDITIONAL TESTING AND MO NITORING NECESSARY TO DETERMINE WHETHER FLUID MOVEMENT IS OCCURRING INTO OR B ETWEEN USDWS THAT WOULD ENDANGER A USDW.

Basis for CCS Group Comments: There should be no need for corrosion monitoring of most injected CO2 streams because thos e streams will typical ly overwhelmingly CO2 and dry thus having no corrosive pr operties. Industry experience with
p roduction, transportation, an d injection of dry CO2 st rongly illustrates the non-corrosive nature of this type of CO2 stream.

This proposal revises the provision to make it a requirement only where appropriate based on the materials of construction and characteristics of the injected CO2 stream and other factors.

The corrosion provisions are included in subsection (c)(5).

Response: EPA believes that quarterly corrosion monitoring of GS we lls is necessary. CO2 in the
p resence of water (including water with NOx, SOx, and H2S impurities) can be corrosive to well materials and cements. Thus, although a CO2 stream may be dry, the pot ential for corrosion of well materials down-hole, where th e injectate can potentially mix with water in the target formation, must beconsidered.

Several laboratory studies and a limi ted number of field studies have i nvestigated and characterized the effects of carbonic acid on well materials. Laborat ory studies (e.g., Kutchko et al., 2007; Kutchko et al., 2008) consistently identify alterations (typically car bonation) of cement as the result of interactions between cement and CO2-saturated brine.

Currently, there are only a few analys es of cement from wells that have been in prolonged contact with CO2 in actual field (down-hole) c onditions. Evaluation of cement from a well at the Scurry Area Canyon Reef Operators Committee (SACROC) site show ed alteration, but did not show degradation that compromised the structural integrity of the ceme nt (Carey et al., 2007). In another study, cement samples were collected and analyzed from a CO 2 production well in a natural CO2 reservoir in Colorado exposed to a CO2-water down-hole envir onment for 30 years (Crow et al., 2008). The study found evidence of reaction between th e CO2-rich water and the cement.

Oil industry research also addresses the effects of corrosion of steel tubing and pipes. Lopez et al. (2003) noted that 60 percent of oilfield failures are related to the effects of carbonic acid from produced brines on carbon and low alloy steels.

Laboratory investigation of cement alteration/degradation is an ongoi ng research area. Few field-based studies have been completed to date. The laboratory and field studies currently available suggest that corrosion problems can be managed; however, there is not a large e nough body of research to rule out
p otential corrosion problems of st eel components of injection well s. The IPCC (2005) report on carbon dioxide capture and storage reviewed oil and gas i ndustry experience with gas injection wells, close industry analogues to CO2 injection wells. The repor t stated that, while the design of CO2 injection wells will be very similar to ga s injection wells, most down-hole co mponents of the CO2 injection wells will “need to be upgraded for higher pressure ratings and corrosion resistance.” Given the pressure and corrosion considerations, anticipated long lifespan of a GS well and the difficulties that would be associated with a corrosion-relate d well failure, EPA believes thatcorrosion monitoring in the downhole environment is justified. For these reasons, the fi nal rule requires quarterly corrosion monitoring at §146.90(c).

EPA maintains that plume tracking and pressure m onitoring are key component s of monitoring at GS sites. A rigorous plume tracking and pressure m onitoring scheme, such as one that meets the requirements at §146.90(g), is impera tive for ensuring that the CO2 plume is contained within the injection zone. Pressure monitoring in the injection zone is necessary to track the development and movement of the pressure front and CO2 plume. When combined w ith information on temperature,
p ressure data provide an indication of the phase (e.g., gas, supercritical) and distribution of the injected CO2. Monitoring can also identify needed remedi al actions, provide inputs for AoR reevaluation modeling, evaluate predictions of plume movement , and target additional geochemical and surface monitoring needs.

EPA also believes that the ground water geochemical monitoring outlined in §146.90(d) will maximize
p rotection of USDWs from endangerment at GS sites. Direct geochemical sampling is an important part of a monitoring program. See the final rule and prea mble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4660 2.6.6 Geochemical monitoring Comment: Rule Provision: 146.90(d) Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24481Proposed CCS Group Recommendations: (d ) Periodic monitoring of the ground water quality and geochemical changes above the confining zone(s) that may be a result of carbon dioxide movement th rough the confining zone or additional identified zones:

(1) The location and number of monitoring wells must be based on specific information about the geologic sequest ration project, in cluding injection rate and volume, geology, the presence of artificial penetrations and other factors;

(2) The monitoring frequency and spatial distribution of monitoring wells must be based on baseline geochemical data that has been collected under § 146.82(a) (6) and any modeling results in the ar ea of review evaluation required by § 146.84(b);

Response: EPA did not make the suggested changes, but ag rees that monitoring pl ans and methods need to be site-specific and based on baseline data and data collected throughout operations. EPA believes that the monitoring requirements for GS sites at §146.90 provide an appropriate level of flexibility in structuring a testing and monitoring plan that protects USDWs from endangerment.

The final regulation provides for flexibility in: 1) met hodologies used to collect these data, 2) the spatial resolution at which the data should be collected, a nd 3) how often the data should be collected. The number and placement of monitoring wells will be based on site-sp ecific information such as the calculated AoR, injection rate and volume, site geology, baseline data, and the presence of artificial
p enetrations within the AoR. In some instances, ther e may be a limited number of options for complying with EPA's minimum requirements. For example, monitoring for geochemical ch anges will require use of monitoring wells and collection of groundwater samples for chemical analysis. Many options currently exist for complying with other requirement s, such as tracking the position of the plume and
p ressure front within the injection zone.

Flexibility is also provided regarding how to monito r for the specific data required by the final rule. The testing and monitoring plan is developed by the owner or operator in consultati on with the Director and is designed to ensure that a detailed, Director -approved document describing how monitoring will be conducted during the lifetime of the project exists. EPA is de veloping guidance on testing and monitoring to assist owners or operators and Directors in evaluating requirements under §146.90, including proposed monitoring plans. The guidance describes availabl e technologies and recommended approaches for implementing a testing and monitoring plan, in cluding pre-operational geophysical logging and testing of injection we lls, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: Rule Provision: 146.90(e) & (f)

Proposed CCS Group Recommendations: (e) A demonstration of external mechanical Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24482integrity pursuant to § 146.89(c) at leas t once per year throughout the duration of the geologic sequestration project;

(f) A pressure fall

- off test at least once every fi ve years unless more frequent testing is required by the Director based on site specific information;

Basis for CCS Group Comments: Redundant to section 146.89

These issues are addressed in reco mmended subsection (b)(3) and (4).

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final appr oach. EPA adds that the purpose of including all testing and monitoring requirements in §146.90 is to clarify and to specify the content of the required testing and monitoring plan.

Other EPA Comment Codes and Descriptions: 4650 2.6.5 CO2 plume and pressure front tracking (seeking comment) Comment: Rule Provision: 146.90(g)

Proposed CCS Group Recommendations: (g) Testing and monitoring to track the extent of the carbon dioxide plume and the position of the pressure front by either monitoring for pressure change s in the first formation overlying the confining zone or using indirect, geophysical techniques (e.g., seismic, electrical, gravity, or electromagnetic su rveys and/or down

- hole carbon dioxide detection tools);

Basis for CCS Group Comments: Monitoring out side of the injection zone provides little information of value for tracki ng and monitoring the injected plume. Examples of how to test and monitor coul d be included in the Preamble but need not be included in the rule itself.

Response: EPA has revised this requirement in the fina l rule. The final GS regulation, at §146.90(g)(1), requires all GS project owners or operators to moni tor for pressure changes in the injection zone. EPA believes that pressure monitoring in the injecti on zone is necessary to track the development and movement of the pressure front and CO2 plume.

Pressure monitoring within the injection zone is necessary because any such monitoring above the confining zone would not detect movement of the pr essure front unless a breach of the confining zone occurs. EPA believes that monitoring using wells in th e injection zone (i.e., that penetrate the confining zone) can be safely performed if the wells are constructed to prevent flow between the injection zone and USDWs or other layers above the confining z one. Such construction technologies exist and have been used in the oil and gas indus try for years. EPA believes that the benefits of monitoring in the injection formation outweigh the mana geable risk of those monitoring we lls serving as conduits for fluid movement. EPA adds that owners or operators may consider perfor ming additional pressure monitoring in wells that are above th e confining zone (e.g., in the same well s used to perform ground water quality monitoring required at §146.90(d)) to provide additi onal verification that no pressure changes are occurrin g above the confinin g zone due to CO2 leaka g e. Monitorin g also identifies needed remedial Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24483actions, provides inputs for AoR r eevaluation modeling, and targets a dditional geochemical and surface monitoring needs. Knowledge of the location of the CO2 plume and the associated pressure front will assure the public that GS projects are proceeding accord ing to plan, provide sufficient information to the owner or operator and Director, or allow for appropriate actions to address any indication that USDWs may be endangered.

EPA acknowledges that, at ce rtain sites, there may be a need for more or different monitoring schemes (which may include monitoring in the confining zone), and adds that it is important to balance the need for adequate monitoring that ensures USDW protec tion from endangerment agai nst too many artificial
p enetrations which could serve as conduits for fluid migration. Site-specific te sting and monitoring plans should describe the proposed monitoring regime, which must be approved by the Director. Flexibility is also provided regarding how to monito r for the specific data required by the final rule. The testing and monitoring plan is developed by the owner or operator in consultati on with the Director and is designed to ensure that a detailed, Director -approved document describing how monitoring will be conducted during the lifetime of the project exists.

EPA is developing guidance on testing and monitoring to assist owners or opera tors and Directors in evaluating requirements under §146.90, in cluding proposed monitoring pl ans. The guidance describes available technologies and recommended approaches for implementing a test ing and monitoring plan, including pre-operational geophys ical logging and test ing of injection wells, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4670 2.6.7 Surface air monitoring and/or soil gas monitoring (seeking comment) Comment: Rule Provision: 146.90(h)

Proposed CCS Group Recommenda tions: (h) At the Director ’ s discretion, surface air monitoring and/or soil gas monitoring to detect movement of carbon dioxide that could endanger a USDW.

(1) The testing and monitoring plan must be based on potent ial vulnerabilities within the area of review;

(2) The monitoring frequency and spatial distribution of surface air monitoring and/or soil gas monitoring must reflect baseline data and the monitoring plan must include how the proposed monitoring will yield useful information on the area of review delineation and/or compliance with standards under 40 CFR 144.12;

Basis for CCS Group Comments: In most situations soil and air monitoring does not provide an effective method of protecting USDWs.

Response: EPA acknowledges that air and soil gas monitoring to ensure USDW protection is not necessary at all GS sites and agrees that the deci sion to use surface monitoring and th e selection of monitorin g methods for the purpose of USDW protection will be site-specific. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24484The Agency believes that surface air and soil gas monitoring, when coupled with subsurface monitoring, may be appropriate at some GS projects to en sure USDW protection. EPA also acknowledges that surface air and soil gas measurements are subject to va riability and may not be suitable in all settings as a method to ensure USDW protection. However, EPA doe s not believe that this should entirely preclude their use. The decision to use surf ace monitoring and the se lection of monitoring me thods will be sitespecific (e.g., may be influenced by geology, inject ion depth, and operational conditions) and must be based on potential risks to USDWs within the AoR.

In the final rule, at §146.90(h), the decision to requi re such monitoring as an additional measure to ensure USDW protection rests with th e Director as a means of identify ing leaks that may pose a risk to USDWs and informing emergency notif ication of a Class VI owner or operator and UIC Director in the event of a USDW endangerment, pursuant to requirements at §146.91(c).

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Rule Provision: 146.90(i) & (j)

Proposed CCS Group Recommendations: (i) Any additional monitoring, as required by the Director, necessary to support, upgrade, and improve computational modeling of the area of review eval uation required under § 146.84(b) and to determine compliance with standards under 40 CFR 144.12; and

(j) A quality assurance and surveillance plan for all testing and monitoring requirements.

Basis for CCS Group Comments: These issues are addressed in subsection (c)(6) and (b)(5) respectively.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA ha s made many revisions to the GS rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4760 2.7.6 Proposed reporting frequency (seeking comment) Comment: Rule Provision: 146.91(a)

Proposed CCS Group Recommendations: (a) Se mi-annual OR LESS FREQUENT AT THE DISCRETION OF THE DIRECT OR reports containing:

Basis for CCS Group Comments: Over the life of the project, the Director may decide that less reporting is acceptable

Response: EPA is retaining the semi-annual reporting requi rement in the final rule at §146.91(a) in order to ensure that permittin g authorities can maintain proper oversi g ht of GS pro j ects, particularl y in Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24485

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24486the early stages of rule implementation and deploym ent of GS technologies. Th e Agency also clarifies that permitting authorities may choose to require more frequent reporting, at the discretion of the Director. See the final rule and preamble for furthe r discussion on EPA's final a pproach to reporting and recordkeeping.

EPA is using an adaptive approach to regulating GS . The Agency plans to, every six years, collect and review data on GS projects, including operational data , to determine whether the appropriate amount and types of information and appropr iate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

Other EPA Comment Codes and Descriptions: 4720 2.7.2 Operational recor dkeeping and reporting Comment: Rule Provision: 146.91(a)(1)

Proposed CCS Group Recommenda tions: (1) Any SIGNIFICANT changes to the physical, chemical and other relevant characteristi cs of the carbon dioxide stream from the proposed operating data;

Basis for CCS Group Comments: (1) Technica l clarification. Significance can be determined by a statistical analysis of the data. Rules should recognize that there will be minor variations in many data sets over time.

Response: EPA retained this provision as proposed. The final rule at §146.91(a)(3) requires reporting of all exceedances of operating parameters. EPA disagr ees with the suggestion to report only "significant" exceedances. Making a determination as to whether an exceedance is "significant" is not the purpose of the requirement. EPA believes that the ability of an operator to consistently meet operating requirements and avoid exceedances provides evidence of a well-man aged GS project that is in compliance with the Class VI permit. If multiple exceedances occur, the Director should be aware of such occurrences, and that information will aid in his/ her determination of whether these indicate problems at the site, and what is the appropriate course of action (e.g., a well workover, modification of operating parameters, or imposition of a penalty) to remediate such problem(s).

Other EPA Comment Codes and Descriptions: 4720 2.7.2 Operational recor dkeeping and reporting Comment: Rule Provision: 146.91(a)(3) & (4)

Proposed CCS Group Recommendations: (3) A de scription of any SIGNIFICANT event that exceeds operating paramete rs for annulus pressure or injection pressure as specified in the permit;

(4) A description of any SIGNIFICANT ev ent which triggers a shutdown device required pursuant to §146.88(e) and the response taken;

Basis for CCS Group Comments: EPA should c onsider some significance threshold on reporting these events to avoid reporting events that would be of limited interest or consequence. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24487

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24488Response: EPA retained this provision as proposed. The final rule at §146.91(a)(3) requires reporting of all exceedances of operating parameters. EPA disagr ees with the suggestion to report only "significant" exceedances. Making a determination as to whether an exceedance is "significant" is not the purpose of the requirement. EPA believes that the ability of an operator to consistently meet operating requirements and avoid exceedances provides evidence of a well-man aged GS project that is in compliance with the Class VI permit. If multiple exceedances occur, the Director should be aware of such occurrences, and that information will aid in his/ her determination of whether these indicate problems at the site, and what is the appropriate course of action (e.g., a well workover, modification of operating parameters, or imposition of a penalty) to remediate such problem(s).

Other EPA Comment Codes and Descriptions: 4720 2.7.2 Operational recor dkeeping and reporting; 4740 2.7.4 Electronic reporti ng (seeking comment) Comment: Rule Provision: 146.91(b) & (c)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment and the final rule retains the text as proposed. See the final rule and preamble for further discussion on EPA's final approach to repor ting and recordkeeping.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(a)

Proposed CCS Group Recommendations: (a) Prior to the well plugging, the owner or operator must flush each Class VI inject ion well with a buffer fluid, determine bottomhole reservoir pressure , and perform a final EXTERNA L mechanical integrity test OF ANY RELEVANT WELLBOR E MATERIALS REMAINING.

Basis for CCS Group Comments: Many of the co mponents that would be tested by an internal MIT are removed or test ed during the plugging process.

Rule Provision: 146.92(b)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Rule Provision: 146.192(b)(2) & (5)

Proposed CCS Group Recommendations: (2) Appropriate testing methods to ensure FINAL EXTERNAL mechanical integr ity as specified in §146.89(C); ...

(5) The t y pe and g rade and quantit y of material to be used in plu gg in g . The Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24489

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24490material must be SUIT ABLE FOR USE with the ca rbon dioxide stream; and

Basis for CCS Group Comments: Many of the co mponents that would be tested by an internal MIT are removed or test ed during the plugging process.

Response: Regarding the suggested edit at 146.92(b)(2), EPA agrees that only an external MIT is required, and has modified the GS rule at §146.92(a) and 146.92(b) to require owners or operators to
p erform a final external mechanical inte grity test prior to the well plugging.

Regarding the edit at 146.92(b)(5), EPA believes, cons idering the potentially corrosive nature of CO2 when it is in contact with water, that the requirement that the material must be compatible with the CO2 stream is appropriate. The final rule retains this requirement.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(c)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the commenter’ s support and the final rule retains this approach.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(d)

Proposed CCS Group Recommendations: (d) Pl ugging report. Within 60 days after
p lugging the owner or operator must submit a plugging report to the Director. If the semi

- annual report is due less than 15 days after completion of
p lugging, then the report must be subm itted within 60 days after plugging. The report must be certified as accurate by the owner or operator and by the person who performed the plugging operation (if other than the owner or operator.)

Basis for CCS Group Comments: The proposed change will simplify and clarify a
p rovision that is unnecessarily complicated.

Response: EPA has revised the text at §146.92(d) to reduce c onfusion. The final rule text reads, "Within 60 days after plugging the owner or operator must submit a pluggi ng report to the Director." Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24491

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24492

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24493Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities Comment: Rule Provision: 146.93(a)(1)

Proposed CCS Group Recommendations: (1) Th e owner or operator must submit the
p ost

- injection site care and site closur e plan as a part of the permit application to be approved by the Director. SHALL CONTINUE TO CONDUCT MONITORING AS SPECIFIED IN THE DIRECTOR-APPROVED PO ST-INJECTION SITE CARE AND SITE CLOSURE PLAN, PURSUANT TO THE PERFORMANCE BASED CRITERIA DESCRIBED IN 146.93(B)(3).

Basis for CCS Group Comments: Revisions here reflect changes to §146.93(b)(3)

Response: EPA disagrees with the suggested changes, a nd disagrees that the post-injection monitoring
p eriod should be stri ctly performance- b ased. The Agency agrees that ther e will be limited circumstances where it can be demonstrated in less than 50 year s that the plume and pressure front no longer pose a risk of endangerment to USDWs, and has included re quirements in the final Class VI rule at §146.93(c) for an owner or operator to substantially demonstr ate that an alternative time frame ensures the
p rotection of USDWs. However, EPA anticipates that a default timefr ame for post-injection site care will necessary for most GS sites to ensure the protection of USDWs. A 50-year post-injection site care timeframe represents a r easonable and protective monitoring peri od based on a review of research studies, industry reports, and existi ng environmental programs, and ev aluation of public comments. For this reason, the final GS regulation includes a provision that the Director may, at his or her discretion, shorten the post-injection site care timeframe if the owner or operator can demonstrate that the GS
p roject does not pose an endangerment to USDWs, as specified in §146.93(b)(2). Such a demonstration will be site-specific, and based on pressure monitoring and USDW impacts.

The GS rule requires owners or operat ors to submit a post-injection site care and site closur e plan as part of the permit application, as specified in §146.82(a), in order to outline how these activities will be
p erformed and how non-endangerment of USDWs will be demonstrat ed throughout the post-injection site care period.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93); 5220 2.8.2.1 Post-injec tion monitoring activities Comment: Rule Provision: 146.93(a)(2)

Proposed CCS Group Recommendations: (2) The post

- injection site care and site closure plan must include the following information:

(i) The pressure diffe rential between pre

- injection and predicted post

- injection
p ressures in the injection zone;

(ii) The predicted position of the carbon dioxide plume and a ssociated pressure front at site closure as demonstrated in the area of review evaluation required under § 146.84(b);

(iii) A description of post

- in j ection monitorin g location, methods, and proposed Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24494frequency; and

(iv) A proposed schedule for submitting post

- injection site care monitoring results to the Director.

Basis for CCS Group Comments: Revisions here reflect changes to §146.93(b)(3)

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.93(a)(3)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA agrees that a post-injection site care monitoring plan is an important tool for GS and anticipates that, in some cases, the appropriate post-injection monitoring strategy may end up being different than initially pr ojected and there may be a need to amen d the post-injection site care and site closure plan. EPA is requiring that, upon the cessati on of injection, the owner or operator submit an amended post-injection site care and site closure plan or demonstr ate to the Director that no changes to the original post-injection site care and site closure plan are necessary (146.93(a)(3)). EPA is not requiring formal periodic review and updates to the PI SC and site closure plan throughout the injection
p hase.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5200 2.8.2 Post injecti on site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.93(a)(4)

Proposed CCS Group Recommendati ons: 4) AT ANY TIME DURI NG THE POST-INJECTIONSITE CARE PHASE, The owner or operator may modify and resubmit the postinjection site care and site closure plan for the Director’s approval within 30 days of such change.

Basis for CCS Group Comments: Technical Clarification.

Response: EPA agrees that a post-injection site care monitoring plan is an important tool for GS and anticipates that, in some cases, the appropriate post-injection monitoring strategy may end up being different than initially pr ojected and there may be a need to amen d the post-injection site care and site closure plan. EPA is requiring that upon the cessation of injection, th e owner or operator submit an amended post-injection site care and site closure plan or demonstr ate to the Director that no changes to the ori g inal post-in j ection site care and site closure plan are necessar y (146.93(a)(3)). EPA is not Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24495

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24496requiring formal periodic review and updates to the PI SC and site closure plan throughout the injection
p hase. EPA does not expect that changes to this plan would be implemented until injection operations cease. EPA envisions that owners or operators would take into account similar considerations that guide updates to other project plans, e.g., monitoring and operational data and results of AoR reevaluations. EPA adds that, if any mon itoring or other site data indicate a need for amendi ng the post-injection site care plan, the owner or operator is expected to amend the plan accordingly under §146.93(a)(3).

EPA adds that, in the final rule, it has revised th e text at §146.93(a)(4) as foll ows: "At any time during the life of the geologic sequestration project, the owner or opera tor may modify and resubmit the postinjection site care and site closure plan for the Di rector’s approval within 30 days of such change."

EPA is issuing guidance on development and updating of the GS project plans, including the postinjection site care and site clos ure plan. The guidance will be available on EPA's web site at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities; 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: Rule Provision: 146.93(b)

Proposed CCS Group Recommendations: (b) The owner or operator shall monitor the site following the cessation of injecti on to show the position of the carbon dioxide plume and pressure front and demonstrate that USDWs are not being endangered.

(1) The owner or operator shall continue to conduct monitoring as specified in the Director-approved post-injection site care and site closure plan, UNTIL CLOSURE IS AUTHORIZED PURSUANT TO 146.93(B)(3).

Basis for CCS Group Comments: EPA should al so reconsider its proposed 50-year default period for post-injection site car e. EPA offers no ra tionale for this arbitrarily-selected period of 50 years. Establishing a fixed and unusually long time period may create a significant barrier for operators considering entry into CCS operations. Criteria for determin ing the period for post-injection site care should be performance-based and a function of the site specific characteristics of a project such as project size, geologic factors, and relative risk of the project. Such cr iteria are provided in our edits to §146.93(b)(3).

Response: EPA disagrees that a post-injection site care ti meframe of 50 years is excessive in most cases or arbitrary. EPA proposed a default post-injection site care timeframe of 50 years based on a review of research studies, industry reports, and existing envir onmental programs. This analysis was included in an EPA-prepared background document that is available in the fede ral docket, titled "Computational Modeling of Underground In jection of Carbon Dioxide for Dete rmination of Area-of-Review and Potential Risk to Underground Sources of Drinking Water." EPA assessed various default timeframes based on additional review of re search studies and evaluation of public comments. While numerous commenters suggested that EPA shorten the monito ring timeframe, none of the commenters provided sufficient data or other evidence to warrant a ch ange in the proposed time frame. While the 10- or 30-
y ear timeframe su gg ested b y some of these commenters ma y be within the timeframe su gg ested in some Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24497studies, EPA believes that the potential risks of e ndangering USDWs will likely not decline within these timeframes and available data, including data submitted by commenters, do not support a different default timeframe. However, EPA acknowledges ther e will be circumstan ces where it can be demonstrated in less than 50 years that the pl ume and pressure front no longer pose a risk of endangerment to USDWs. For this reason, the GS rule offers owners or operators flexibility regarding the duration of the PISC timeframe by: (1) allowing th e Director discretion to shorten or lengthen the PISC timeframe during the post-inj ection period based on site-specific data, pursuant to requirements at §146.93(b); or (2) affording the Direct or discretion to allow a Class VI well owner or operator to demonstrate, during the permitting pr ocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangermen t of USDWs pursuant to requirements at §146.93(c).

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe for
p ost-injection site care will be necessary in most cases. The default 50 year post-injection site care timeframe represents a r easonable and protective monitoring peri od based on a review of research studies, industry reports, and exis ting environmental programs, and evaluation of public comments. EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts.

EPA adds that the purpose of the GS rule is not to incentivize the use of GS; rather, the purpose of the GS rule is to ensure that, where GS is deployed, it is conducted in a manner that protects USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities; 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: Rule Provision: 146.93(b)(2)

Proposed CCS Group Recommendati ons: (2) If the owner or operator can request and demonstrate to the satisfaction of th e Director before 50 years, based on monitoring and other site

- specific data, that the geologic sequestration project no longer poses an endangerment to USDWs, the Director may approve an amendment
to THAT the post-injection site care and site closure plan SHOULD BE REVISED to reduce the frequency of monitoring, THE DIRECTOR SHALL APPROVE THE REDUCTION. or may authorize site closur e before the end of the 50

- year period.

Basis for CCS Group Comments: See rationale stated above for eliminating 50-year
p eriod.

Response: As described above, EPA disagrees that a post-in jection site care timeframe of 50 years is excessive in most cases or arbitrar y, and retains the default 50-year pos t-injection site care timeframe in the final rule. Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24498

Commenter Name: Robert F. Van Voorhees Letter ID: 0190Other EPA Comment Codes and Descriptions: 5280 2.8.2.4 USDW non-endangerment demonstrations Comment: Rule Provision: 146.93(b)(3)

Proposed CCS Group Recommendations: (3) Prior to authorization for site closure, the owner or operator must DEMONSTRATE TO THE DIRECTOR, BASED ON MONITORING, OTHER SITE-SPECIFIC DATA, AND MODELING THAT IS REASONABLY CONSISTENT WITH SITE PERFORMANCE, THAT NO ADDITIONAL MONITO RING IS NEEDED TO ASSURE THAT THE GEOLOGIC SEQUESTRATION PROJECT DOES NOT AND IS NOT EXPECTED TO POSE AN ENDANGERMENT TO USDWS. THE DIRECTOR SHALL APPROVE CLOSURE IF THE OWNER OR OPERATOR DEMONSTRATES, BASED ON THE CURRENT UNDERSTANDING OF THE SITE, INCLUDING MONITORING DATA AND/OR MODELING, ALL OF THE FOLLOWING: (I) THE ESTIMATED MAGNITUDE AND EXTENT OF THE PROJECT FOOTPRINT (CO2 PLUME AND THE AR EA OF ELEVATED PRESSURE) ; (II) THE ESTIMATED LOCATION OF TH E DETECTABLE CO2 PLUME; (III) THAT THERE IS NO SIGNIFICANT LEAKAGE OF EITHER CO2 OR DISPLACED FORMATION FLUIDS THAT IS ENDANGERING USDWS; (IV) THAT THE IN JECTED OR DISPLACED FLUIDS ARE NOT EXPECTED TO MIGRATE IN THE FUTURE IN A MA NNER THAT ENCOUN TERS A POTENTIAL LEAKAGE PATHWAY INTO A USDW; (V) THAT THE INJECTION WELLS AT THE SITE COMPLETED INTO OR THROUGH THE INJECTION ZONE OR CONFINING ZO NE ARE PLUGGED AND ABANDONED IN ACCORDANCE WITH THESE REQUIREMENTS; AND (VI) AN Y REMAINING PROJECT MONITORING WELLS AT THE SITE ARE BEING MANAGED BY A PERSON AND IN A MANNER ACCEPTABLE TO THE DIRECTOR.

Basis for CCS Group Comments: We believe there are three problems with the closure standard in proposed section 146.93(b). First, the presumption that monitoring should continue for 50 years is unnecessary and counterproductive. A straight performance standard is preferab le to this or any other fixed time
p eriod because it provides a clearer standard and an incentive to maximize the understanding of site and project performanc e and as such is more protective of USDWs. Second, the proposal requires a showing that the CO2 plume has "stabilized", which is undefined. Cessation of plume movement is not necessarily essential to show that a project poses no threat of endangerment to USDWs-plumes that are still moving may, nonetheless, re main contained. Instead, it is more
p rotective to show that the plume is not expected to encounter a leakage
p athway. Third, the required showing that "no additional monitoring is needed" does not provide guidance regarding how an operator is to show that no additional monitoring is n eeded. The proposal below provides specific guidance on what the operator must show. Commenter Or g anization: Carbon Sequestration Council Comment ID: 24499We recommend the standard in the propos ed alternative language for section 146.93(b) below because it sets forth detailed criteria, all of which must be satisfied, to demonstrate that the site does not pose an endangerment to USDWs. The specific criteria listed in our proposal will serve to provide the Director with the requisite information to make the appropriate determination. The advantage of this approach is that it establishes clear criteria that an operator must demonstrate before obtaining site closure based upon particular site characteristics and is, therefore, reasonably applicable to any storage site as opposed to a standard based upon a fixed-duration. Furthermore, it is more stringent than a purely discretiona ry approach because it establishes specific criteria that must be shown be fore site closure may be granted. We believe this language, which is an extens ion of work done by the World Resources Institute and the Ground Water Protection C ouncil, avoids the not ed shortcomings and provides stronger protection for USDWs.

This is the same recommendation as pres ented by the multi-stakeholder group, in which the Carbon Sequestration Council participated.

Response: EPA disagrees that the rule should specify the criteria for setting th e monitoring timeframe. Instead, EPA believes that such de terminations are site-specific and should be described in a project specific post-injection site care and site closure plan. EPA also be lieves that periodic reviews and updates, where necessary, to the plan are important to ensuring that the site continues to be managed effectively and to determine wh ether shortening the monitori ng timeframe is appropriate. The post-injection site care requirements in the final GS rule incorporate a combination of a fixed timeframe and a performance standard approach. The final GS rule offe r owners or operators flexibility regarding the duration of the PISC timeframe by: (1 ) allowing the Director di scretion to shorten or lengthen the PISC timeframe during the post-injection period based on site-specific data, pursuant to requirements at §146.93(b); or (2) affo rding the Director discretion to allow a Class VI well owner or operator to demonstrate, during the permitting process based on substantial data, th at an alternative PISC timeframe may be appropriate if it ensures non-endangerment of US DWs pursuant to requirements at §146.93(c).

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts. EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and monitoring wells, perform post-injection m onitoring, demonstrate the appropriateness of an alternative post-injection site care time fr ame, demonstrate non-endangerment, and perform site closure activities. The guidance will be available at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24500Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment); 5260 2.8.2.3 Adjusting the post-injection timeframe (seeking comment) Comment: Rule Provision: 146.93(b)(4)

Proposed CCS Group Recommendations: (4) If such a dem onstration cannot be made (i.e., if the carbon dioxide plume and pre ssure front have not stabilized) after the 50

- year period, the owner or operator must submit to the Director a plan to continue post

- injection site care.

Basis for CCS Group Comments: No longer n ecessary with 50-year period deletion.

Response: As described above, EPA believes that to en sure USDW protection from endangerment, a default timeframe for post-injection si te care is necessary in most ca ses. A 50-year post-injection site care timeframe represents a reasona ble and protective monitoring peri od for most GS sites based on a review of research studies, industry reports, and existing environmental programs, and evaluation of
p ublic comments.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care Comment: Rule Provision: 146.93(c)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment and the final rule retains the text as proposed.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.93(d)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the commente r’s support; the final rule retains this provision.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Rule Provision: 146.93(e)

Proposed CCS Group Recommendations : (e) Once the Director has Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24501

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24502

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24503authorizeS d site closure, the owner or opera tor must submit a site closure report within 90 days that must thereafter be retained at a location designated by the Director. AFTER COMPLETION OF ALL CLOSURE OPERATIONS. The report must include:

(1) Documentation of appropriate inje ction and monitoring well plugging as specified in §146.92 and paragraph (c) of this section. The owner or operator must provide a copy of a survey plat wh ich has been submitted to the local zoning authority designated by the Director . The plat must indicate the location of the injection well(S) relative to perm anently surveyed benchmarks. The owner or operator must also submit a copy of the plat to the Regional Administrator of the appropriate EPA Regional Office;

Basis for CCS Group Comments: Once the site closure report is submitted to the Director, the operator cease to bear re sponsibility for any further record retention. At this point, EPA becomes the steward of information for the
p roject.

Rule Provision: 146.93(e)(2)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Rule Provision: 146.93(f)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Rule Provision: 146.93(g)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA disagrees that the owner or operator should not be responsible for record retention such as site closure reports. EPA believes that the require ments that the owner or operator retain for ten years following site closure, records collected during the post-injecti on site care period at §146.93(f) and §146.93(h) are appropriate for the post-injection and site closure period to ensure that data are available to support non-endangerment de monstrations and to address any con cerns that may arise following site closure. This data will also suppor t EPA's review of project data as part of the adaptive rulemaking approach.

The GS regulation at §146.93(g) require s the owner or operator to record a notation on the deed to the facility property or other similar doc ument examined during a title search that the land has been used to sequester CO2 at the time of site closure.

EPA acknowledges the commenter’s suppor t of the other parts; the final rule retains these provisions.Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: Rule Provision: 146.94(a)

Proposed CCS Group Recommendations: (a) As part of the permit application, the owner or operator must provide the Direct or with an emergency A RISK-BASED remedial response plan that describes acti ons to be taken to address movement of the injection or formation fluids that may cause an endangerment to a USDW during construction, ope ration, closure and pos t-closure periods.

Basis for CCS Group Comments: Any respons e plan should be based on a risk assessment and risk management approach that accounts not only for potential causes of endangerment, but probabilities and potential timing of occurrence as determined on a site-specific basis. As EPA has recognized, "The SDWA does not
p rovide authority to develop regulations for all areas related to GS." 73 Fed. Reg. at 43495. Accordingly, the nature and scope of any such plans will necessarily be limited to the extent of that authority.

Response: EPA agrees that emergency and remedial response plans should be risk-based, however, EPA did not make the requested change. The Agency believes that the require ment to develop a sitespecific emergency and remedial response plan that is informed by required site characterization data collected under per §146.82, modeling for AoR ev aluations and reevaluations, per §146.84, and monitoring data, per §146.90, will appr opriately address commenter concerns regarding the need for a risk-based emergency and remedial response plan.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: Rule Provision: 146.94(b)

Proposed CCS Group Recommendations: (b) If the owner or operator obtains evidence that the injected carbon dioxide st ream, DISPLACED FORMATION FLUIDS OR and associated pressure front may cause an endangerment to ENDANGERS a USDW, the owner or operator must:

(1) Immediately Cease injection IN A PR UDENT MANNER CONSIDERING CIRCUMSTANCES.

(2) Take all steps reasonably necessary to identify and characterize THE ENDANGERMENT POSED;

(3) Notify the Director or the designat ed representative within 24 hours OF BECOMING AWARE OF TH E ENDANGERMENT; and

Basis for CCS Group Comments: Technical clarifications.

Under some circumstances, an immediate cessation of in j ection could have adverse Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24504

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24505impacts on other aspects of the operation.

Rule Provision: 146.94(c)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Rule Provision: 146.94(d)

Proposed CCS Group Recommendations: (d) Th e owner or operator must notify the Director prior to conducting any well workover IN RESPONSE TO ANY CASE OF ENDANGERMENT.

Basis for CCS Group Comments: In critic al situations, time spent obtaining approval could adversely affect the ability to conduct operati ons or increase the level of endangerment.

Response: After consideration of comments, EPA has finalized the rule language in §146.94(b) as
p roposed. In the introductory section of §146.94(b), EPA clarifies that the pressure front, as defined in §146.81, is a zone where the pressure differential is suff icient to cause the moveme nt of injected fluids or formation fluids into a USDW. Therefore, displ aced formation fluids are im plicitly included in the requirements for §146.94. EPA also clarif ies that owners or operators must take action when the CO2 stream or pressure front may caus e endangerment. In order to preven t the endangerment of USDWs, as required under §1421 of the SDWA, EPA expects the ow ner or operator to act preemptively and not wait until endangerment has occurred. This language is consistent with exis ting UIC requirements for other well classes and EPA’ s authority under the SDWA.

EPA clarifies that the Agency expects that owners or operators should take care not to damage the well when ceasing injection under §146.94(b)(1). At §146.94(b)(2), EPA is maintaining the requirement to “characterize the release.” In order to prevent the endangerment of USDWs, as required under §1421 of the SDWA, EPA expects the owner or operator to act preemptively and not wait until endangerment has occurred. This language is consistent with existing UIC requirements for other well classes and EPA’s authority under the SDWA.

EPA clarifies that the 24-hour not ification required under §146.94(b)(3 ) begins when the owner or operator obtains evidence of possible endangerment. EPA believes the rule language is clear on this requirement.

Since proposal, EPA has modified the final regulatory language at §146.94(d) to clarify what constitutes a workover to address a well fa ilure (which invokes remedial ac tions) and what constitutes a maintenance-type workover. For maintenance-type workovers (i.e., those that are scheduled in advance), the owner or operator must notify a nd gain approval from the Director prior to beginning the workover. In the final GS regulation, EPA has moved this re quirement to the reporting requirements at §146.91(d) to clarify its intent.

Regarding concerns that notification could delay responses, EPA clarifies th at the GS rule (at §146.94 (b)) describes procedures owners or operators mu st take in emergency situations. Specifically, upon determining that there is a problem with the well that may endanger a USDW, the owner or operator must first cease injection, then take all steps reas onably necessary to identify and characterize any release, notify the Director, and implement the approved emergency and remedial response plan, whichmay include a well workover. EPA believes that ceasing injection (which the owner or operator would do immediately and before notifying the Director) is the immediate action ne cessary to prevent or mitigate endangerment of USDW s, as required under the SDWA.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(2)

Proposed CCS Group Recommendations : Support the proposed language.

Basis for CCS Group Comments: Agree with EPA’s rationale.

Response: EPA acknowledges the comment; th e final rule retains the requirements for logs to be run
p rior to installation of surface casing required at §146.87(a)(2).

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Enhanced recovery of oil or natural gas and geologic seque stration of CO2

EPA’s Proposal would continue to regulat e and permit inject ion of CO2 for EOR/EGR purposes as Class II injection "a s long as any production is occurring." EPA has asked for comment on the merits of this approach "since owners or operators of some Class II EOR/EGR wells may wish to use wells for the purposes of production and GS prior to the field being completely deplet ed." 73 Fed. Reg. at 43502. We recommend that the rules be cl arified to provide more certainty about the applicability of Class II requi rements where GS of CO2 occurs in connection with EOR/EGR activities. Speci fically, the UIC rule s should provide a "bright line" definition as to the applicable class of wells where CO2 injection for EOR/EGR production and for GS occur in tandem. We recommend the following language to accomplish that objective:

[In the paragraphs below, the text in all CAPS denotes added text.]

§ 144.6, 144.80 and 146.5, and Classificati on of injection wells.

Injection wells are classified as follows:

* * *

(b) Class II. Wells which inject fluids:

(1) Which are brought to the surface in connection with conventional oil or natural gas production and may be commingled with waste waters from gas plants which are an integral part of production operations, unless those waters are classified as a hazardous waste at the time of Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24973

Commenter Name: K y le Isakowe r Letter ID: 0191 Commenter Or g anization: American Petroleum Institute Comment ID: 23878injection.

(2) For enhanced recovery of oil or natural gas;

(3) For storage of hydrocarbons which ar e liquid at standard temperature and pressure;

(4) FOR ENHANCED RECOVERY OF OIL OR NATURAL GAS WHERE GEOLOGIC SEQUESTRATION IS OCCURRI NG DURING OR IN CONNEC TION WITH ENHANCED RECOVERY OF OIL OR NATURAL GAS PROVIDED (I) THERE IS REASONABLE EXPECTATION OF MORE THAN INSIGNIFIC ANT FUTURE PRODUCTION VOLUMES OR RATES AS A RESULT OF CARBON DIOXIDE INJECTION AND (II) OPERATING PRESSURES ARE NO HIGHER THAN REASON ABLY NECESSARY TO PRODUCE SUCH VOLUMES OR RATES;

* * *

(F) CLASS VI. WELLS INJECTING A CARB ON DIOXIDE STREAM FOR GEOLOGIC SEQUESTRATION EXCEPT THOSE WELLS DESCRI BED IN SUBSECTION (B)(4) OF THIS SECTION OR OTHERWISE EXCLUDED FROM THIS CLASS.[FN1/]

[FN1/: Please note that well classification for geologic sequestration in certain formations is a matter still under discussi on within the multistakeholder group and may be addressed furt her in future recommendations from the group. In the mean time individual part icipants in these discussions will be expressing views on this and other issues with an openness to revising their views if a consensus can be reached.]

The undersigned have agreed that pr oposed language describing wells in classification (b)(4) establishes a "bri ght line" definition for wells that inject CO2 for EOR/EGR and GS and, consistent with EPA’s intent, should remain in Class II and be subject to the current requirements of Class II. We have also agreed that the wells used for GS in oil and gas reservoirs th at do not meet the criteria of (b)(4) should be subject to additional require ments. We have tentatively defined such wells as wells used "for geologic sequestration in oil and gas formations and where the criteria of paragraph (b)(4) are not met." But we have not yet attempted to define what specific requirements should apply to these wells. We are committed to working toward agreement on those requirements (probably within a Class II context) and submitting the results of that effort to EPA by February 28, 2009 for your consideration.

Response: EPA did not make the suggested change. The Agency disagrees that wells injecting CO2 for the primary purpose of long term storage should be regulated under Class II requirements. The Agency believes that the nature and risk s of CO2 injection for the primary purpose of long term storage poses different risks than injection for the primary purpose of EOR, and ther efore has developed new Class VI regulations to address these unique risks. For example, the volume of CO2 anticipated to be injected for long term storage is significantly greater than for EOR operations. Reservoir pr essure conditions will also be different, with Class VI injection operati ons involving large volumes of CO2 and likely having higher pressures within their storage formations than Class II EOR projects.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Requestfor Comment EPA has made many revisions to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tran sitioning from Class II to Class VI.

Other EPA Comment Codes and Descriptions: 4110 2.4.1.1 Injection pressure limitations Comment: Injection Pressure Limitations

We are concerned about three aspects of proposed section 146.88(a), governing injection pressure limitations. First, it "restricts" fractures in the injection zone "except during stimul ation" rather than focusing on maintaining the integrity of the confining zone, which is what really matters for protecting USDWs. Second, it fails to refer specifical ly to the full ra nge of potential geomechanical failure mode s potentially posed by opera tions at a particular site. Third, the type of geomechanical ri sk that is addressed (initiation or
p ropagation of fractures), is dealt with in a potentially arbitrary fashion (the 90% of fracture pressure limit), which may not be appropriate in all cases.

Our recommended language addresses these concerns by focusing on maintaining the integrity of the confining zone and incl uding tensile failure and shear failure as transmissivity concerns. It calls for additional geomechanical studies of tensile failure and shear fa ilure only "where appropriate " because there will be locations where experience or existing information will provide sufficient evidence to avoid the need for additional studies. The need for conducting additional tests and for determining which tests would be acceptable is left to the Director’s discretion.

The owner or operator must comply wi th a maximum injection pressure limit approved by the Director and specified in the permit. In approving a maximum injection pressure limit, the Director shall consider the results of well tests and, where a ppropriate, geomechanical or other studies that assess the risks of tens ile failure and shear failure. The Director shall approve limits that, with a reasonable degree of certainty, will avoid in itiation or propagation of fractures in the confining zone or cause otherwise non- transmissive faults transecting the confining zone to become tran smissive. In no case may injection
p ressure cause movement of injection or formation fluids in a manner
p rohibited by 40 CFR Part 144.12(a).

Response: EPA notes that because determination of the in jection pressure limit is based on the fracture
p ressure of the injection zone, the lim it is site-specific a nd not arbitrary and is appropriate to protect USDWs from endangerment. EPA emphasizes that injection pressure limits ar e important to protect against fracturing of the confining zone, and that th e requirement at §146.88(a) th at the pressure in the injection zone not exceed 90 percent of the fracture pressure provides a margin of safety in the well operation and protects USDWs from endangerment. If the Director determines, based on a review of the information collected as part of site characterization, that a lower injection pressure limitation is appropriate, the Director has the authority to set a lower limit in the operating permit than the limit established in the rule.

EPA notes that durin g the site characterization process, owners or operators must submit data about the Commenter Name: Kyle Isakowe r Letter ID: 0191 Commenter Or g anization: American Petroleum Institute Comment ID: 23879geology of the site, as specified at §146.82(a), including data on known or suspected faults and fractures and geomechanical information on frac tures, stress, ductility, rock strength, and in situ fluid pressures within the confining zone. The Director will use these data to determine appropriate limits on injection.

In response to the concern about reopening of faults at lower pressures than 90 percent of fracture
p ressure, EPA believes that the requirement for th e owner or operator to submit data on known or suspected faults and fractures and information on the seismic history of the site will inform the determination of an appropriate pr essure limitation in the permit. Any sites with the potential for reopening or reactivation of faults or unacceptable seismic risk that could otherwise interfere with containment will not be pe rmitted as GS sites.

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators in meeting the requirements of §146.82 a nd to assist directors in eval uating permit applications. The guidance will describe recommended approach es for characterizing the regional geology and hydrogeology of a proposed site and performing th e necessary geochemical, geomechanical, and geophysical analyses of the inject ion and confining zone. EPA is al so developing guidance for primacy agencies that will include recommended approaches for evaluating owner or operator-submitted data in setting permit conditions. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: We recommend the standard in the propos ed alternative language for section 146.93(b) below because it sets forth detailed criteria, all of which must be satisfied, to demonstrate that the site does not pose an endangerment to USDWs. The specific criteria listed in our proposal will serve to provide the Director with the requisite information to make the appropriate determination. The advantage of this approach is that it establishes clear criteria that an operator must demonstrate before obtaining site closure based upon particular site characteristics and is, therefore, reasonably applicable to any storage site as opposed to a standard based upon a fixed-duration. Furthermore, it is more stringent than a purely discretiona ry approach because it establishes specific criteria that must be shown be fore site closure may be granted. We believe this language, which is an extens ion of work done by the World Resources Institute and the Ground Water Protection C ouncil, avoids the not ed shortcomings and provides stronger protection for USDWs.

146.93 (b) The owner or operator shall monitor the site following the cessation of injection.

(1) The owner or operator shall c ontinue to conduct monitoring as specified in the Director-approved pos t-injection site care and site closure plan until closure is au thorized pursuant to 146.93(b)(3).

(2) The owner or operator can re quest and demonstrate to the satisfaction of the Director that the post-injection site care and site closure plan should be revised to reduce the frequency of monitoring. Commenter Name: K y le Isakowe r Letter ID: 0191 Commenter Or g anization: American Petroleum Institute Comment ID: 23883Response: EPA disagrees with the suggested edits, but believes that the provisions of the final GS rule at §146.93(b) address the comm enter’s suggestions. Speci fically, the owner or operator must monitor the site until it can be de monstrated that the CO2 plume and pr essure front no longer pose a risk of endangerment to USDWs and that monitoring must continue until the owner or operator demonstrates, based on monitoring and other site-sp ecific data, that no addi tional monitoring is needed to ensure that the GS project does not pose a risk of endangerment to USDWs, as required at §146.93(b)(3). See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5280 2.8.2.4 USDW non-endangerment demonstrations Comment: (3) Prior to authorization for site cl osure, the owner or operator must demonstrate to the Director, based on monitoring, other site-specific data, and modeling that is reasonably consistent with site performance, that no additional monitoring is needed to assure that the geologic sequestration project does not and is not expected to pose an endangerment to USDWs. The Director shall approve closure if the owner or operator demonstrates, based on the current understanding of the site, including monitoring data and/or modeling, all of the following: (i) the estimated magnitude and extent of the project footprint (CO2
p lume and the area of elevated pressu re) ; (ii) the estimated location of the detectable CO2 plume; (iii) th at there is no significant leakage of either CO2 or displaced formation fluids that is endangering USDWs; (iv) that the injected or displaced fluids are not expected to migrate in the future in a manner that enc ounters a potential leakage pathway into a USDW; (v) that the injection wells at the site completed into or through the injection zone or confining zone are plugged and abandoned in accordance with these requirements; and (vi) any remaining project monitoring wells at the site are be ing managed by a person and in a manner acceptable to the Director.

Response: EPA disagrees that the rule should specify the criteria for setting th e monitoring timeframe. Instead, EPA believes that such de terminations are site-specific and should be described in a project specific post-injection site care and site closure plan. EPA also be lieves that periodic reviews and updates, where necessary, to the plan are important to ensuring that the site continues to be managed effectively and to determine wh ether shortening the monitori ng timeframe is appropriate. The post-injection site care require ments in the final GS rule offer owners or operators flexibility regarding the duration of the PISC timeframe by: (1 ) allowing the Director di scretion to shorten or lengthen the PISC timeframe during the post-injection period based on site-specific data, pursuant to requirements at §146.93(b); or (2) affo rding the Director discretion to allow a Class VI well owner or operator to demonstrate, during the permitting process based on substantial data, th at an alternative PISC timeframe may be appropriate if it ensures non-endangerment of US DWs pursuant to requirements at §146.93(c). EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensurin g USDW protection. Both approaches will utilize site-specific data, Commenter Name: K y le Isakowe r Letter ID: 0191 Commenter Or g anization: American Petroleum Institute Comment ID: 23884and be based on pressure mo nitoring and USDW impacts.

EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and m onitoring wells; perform post-inject ion monitoring; demonstrate the appropriateness of an alternative pos t-injection site care time frame; demonstrate non endangerment; and
p erform site closure activities. The guidance will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Enhanced recovery of oil or natural gas and geologic seque stration of CO2

EPA's Proposal would continue to regulat e and permit injection of CO2 for EOR/EGR (enhanced gas recove ry) purposes as Class II in jection "as long as any
p roduction is occurring." EPA has asked for comment on the merits of this approach "since owners or operators of so me Class II EOR/EGR wells may wish to use wells for the purposes of production and GS prior to the field being completely depleted." 73 Fed. Reg. at 43502. We support the Multi-Stakeholder consensus recommendation that the rules be clarified to provide more certainty about the applicability of Class II requirements where GS of C02 occurs in connection with EOR/EGR activities. Speci fically, the UIC rule s should provide a "bright line" definition as to the applicable clas s of wells where C02 injections for EOR/EGR pr oduction and for GS occur in tandem. We strongly support the recommendation for the follow ing language to accomplish that objective:

§ 144.6, 144.80 and 146.5, and Classificati on of injection wells. Injection wells are classified as follows:

***

(b) Class II. Wells which inject fluids:

(1) Which are brought to the surface in connection with conventional oil or natural gas production and may be commingled with waste waters from gas plants which are an integral part of production operations, unless those waters are classified as a hazardous waste at the time of injection.

(2) For enhanced recovery of oil or natural gas;

(3) For storage of hydrocarbons which ar e liquid at standard temperature and pressure;

(4) For enhanced recover y of oil or natural g as where g eolo g ic Commenter Name: Jeff W. Sheets Letter ID: 0192 Commenter Or g anization: ConocoPhillips Comment ID: 23891sequestration is occurring during or in connection with enhanced recovery of oil or natural gas provided (i) there is reasonable expectation of more than insignificant future production volumes or rates as a result of carbon dioxi de injection and (ii) operating
p ressures are no higher than reasona bly necessary to produce such volumes or rates;

* * *

(f) Class VI. Wells inj ecting a carbon dioxide stream for geologic sequestration except those wells descri bed in subsection (b)(4) of this section or otherwise excl uded from this Class.

The Multi-Stakeholder group has agreed that wells in classification (b)(4) should remain in Class II and be subject to the current requirements of Class II. We have also agreed that the wells used for GS in oil and gas reservoirs that do not meet the criteria of (b)( 4) should be subject to additional requirements. We have tentatively defined such wells as wells used "for geologic sequestration in oil and gas formations a nd where the criteria of paragraph (b) (4) are not met" But we have not yet reac hed consensus on defining what specific requirements should apply to these wells. We are committed to working toward agreement on those requirements (probabl y within a Class II context) and submitting the results of that effort to EPA by February 28, 2009 for your consideration.

ConocoPhillips further recommends that Class VI be used for wells designed "exclusively for geologic sequestration of carbon dioxide." This clarifies and broadens Class II to include former produc ing oil and gas wells, EOR wells, EOR with simultaneous storage, and EOR fields transitioning to/from storage, such that all oil and gas fields storing CO2 are Class II, whether producing or not. This approach removes uncertainty for fields which may have become storage fields, but return to production as ec onomic conditions change, or cease
p roduction for some time as part of enhancing rec overy, and possibly other scenarios. This approach acknowledges the track record of CO2 injection for EOR and the significant knowledge base in oil and gas fields. Thus, Class VI requirements would acknowledge the greater uncertainties inherent in often deeper saline storage, newer field de velopments, and possibly less defined closure structures. This approach also may safely accelerate CCS projects utilizing well known oil and gas format ions, public acceptance may be more likely and regulatory authorities/ oil and gas agencies are in place to begin CCS projects. We support API's recommenda tion to add a Class II (b)(S), "For geologic sequestration in oi l and gas formations and where the criteria of
p aragraph (b)(4) are not met".

Response: EPA did not make the suggested change. The Agency disagrees that wells injecting CO2 for the primary purpose of long term storage shoul d be regulated under Class II requirements.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tr ansitioning from Class II to Class VI.EPA is developing guidance on transitioning permits from Class II to Class VI. Th e guidance will assist Directors in determining whether an injection project should be transitioned from Class II where the
p rimary purpose is oil and gas production to Class VI where the primary purpose is long-term storage of large volumes of CO2. The guidance describes the recommended methods the Director may use to evaluate changes in risk to USDWs from project s, and how the Director may determine whether a
p roject should be regulated within th e Class II or Class VI UIC program. This guidance will be available on EPA’s website at http://wat er.epa.gov/type/groundwater/uic/wel ls_sequestration.cfm. For more information, please see the di scussion on transition of Class II wells in the preamble to the final GS rule.

Other EPA Comment Codes and Descriptions: 4110 2.4.1.1 Injection pressure limitations Comment: Injection Pressure Limitations

We are concerned about three aspects of proposed 146.88(a), governing injection
p ressure limitations. First, it "restricts" fractures in th e injection zone "except during stimulation" rather than focusing on maintaining the integrity of the confining zone, which is the suggested focus for protecting USDWs. Second, it misses an opportunity to refer specific ally to the full range of potential geomechanical failure mode s potentially posed by opera tions at a particular site. Third, the type of geomechanical ri sk that is addressed (initiation or
p ropagation of fractures), is dealt with in a potentially arbitrary fashion (the 90% of fracture pressure limit), which may not be appropriate in all cases.

The MSDG's recommended language addresses these concerns by focusing on maintaining the integrity of the confin ing zone and including tensile failure and shear failure as appropriate to ev aluate for potential transmissivity concerns. It calls for additional geomechan ical studies of tensile failure and shear failure only "where appropriate" b ecause there will be locations where experience or existing information will pr ovide sufficient evidence to avoid the need for additional studies. The need for conducting additional tests and for determining which tests would be accep table is left to the Director's discretion. Recommended language:

The owner or operator must comply wi th a maximum injection pressure limit approved by the Director and specified in the permit. In approving a maximum injection pressure limit, the Director shall consider the results of well tests and, where a ppropriate, geomechanical or other studies that assess the risks of tens ile failure and shear failure. The Director shall approve limits that, with a reasonable degree of certainty, will avoid in itiation or propagation of fractures in the confining zone or cause otherwise non- transmissive faults transecting the confiding zone to become tran smissive. In no case may injection
p ressure cause movement of injection or formation fluids in a manner
p rohibited by 40 CFR Part 144.12(a).

Response: EPA notes that because determination of the in jection pressure limit is based on the fracture
p ressure of the injection zone, the limit is site-specific and not arbitrary. EPA em phasizes that injection
p ressure limits are important to prot ect against fracturing of the confining zone, and that the requirement at §146.88(a) that the pressure in the in j ection zone not exceed 90 percent of the fracture pressure Commenter Name: Jeff W. Sheets Letter ID: 0192 Commenter Or g anization: ConocoPhillips Comment ID: 23892p rovides a margin of safety in the well operation and protects US DWs from endange rment. If the Director determines, based on a review of the information collected as pa rt of site characterization, that a lower injection pressure limitation is appropriate, the Di rector has the authority to set a lower limit in the operating permit than the limi t established in the rule.

EPA notes that during the site charac terization process, owners or opera tors must submit data about the geology of the site, as specified at §146.82(a), including data on known or suspected faults and fractures and geomechanical information on frac tures, stress, ductility, rock strength, and in situ fluid pressures within the confining zone. The Director will use these data to determine appropriate limits on injection.

In response to the concern about reopening of faults at lower pressures than 90 percent of fracture
p ressure, EPA believes that the requirement for th e owner or operator to submit data on known or suspected faults and fractures and information on the seismic history of the site will inform the determination of an appropriate pr essure limitation in the permit. Any sites with the potential for reopening or reactivation of faults or unacceptable seismic risk that could otherwise interfere with containment will not be permitted as GS sites.

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators in meeting the requirements of §146.82 a nd to assist directors in eval uating permit applications. The guidance will describe recommended approach es for characterizing the regional geology and hydrogeology of a proposed site and performing th e necessary geochemical, geomechanical, and geophysical analyses of the inject ion and confining zone. EPA is al so developing guidance for primacy agencies that will include recommended approaches for evaluating owner or operator-submitted data in setting permit conditions. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: We recommend the standard in the propos ed alternative language for section 146.93(b) below because it sets forth detailed criteria, all of which must be satisfied, to demonstrate that the site does not pose an endangerment to USDWs. The specific criteria listed in our proposal will serve to provide the Director with the requisite information to make the appropriate determination. The advantage of this approach is that it establishes clear criteria that an operator must demonstrate before obtaining site closure based upon particular site characteristics and is, therefore, reasonably applicable to any storage site as opposed to a standard based upon a fixed duration. Furt hermore, it is more stringent than a purely discretiona ry approach because it establishes specific criteria that must be presented before site closure may be granted. We believe this language, which is an extens ion of work done by the World Resources Institute and the Ground Water Protection C ouncil, avoids the not ed shortcomings and provides stronger protection for USDWs.

146.93 (b) The owner or operator shall monitor the site following the cessation of injection.

(1) The owner or operator shall c ontinue to conduct monitoring as specified in the Directo r -approved post-in j ection site care and site Commenter Name: Jeff W. Sheets Letter ID: 0192 Commenter Or g anization: ConocoPhillips Comment ID: 23904closure plan, until closure is au thorized pursuant to 146.93(b)(3).

(2) The owner or operator can re quest and demonstrate to the satisfaction of the Director that the post-injection site care and site closure plan should be revised to reduce the frequency of monitoring.

Response: EPA disagrees with the suggested edits, but believes that the provisions of the final GS rule at §146.93(b) address the comm enter’s suggestions. Speci fically, the owner or operator must monitor the site until it can be de monstrated that the CO2 plume and pr essure front no longer pose a risk of endangerment to USDWs and that monitoring must continue until the owner or operator demonstrates, based on monitoring and other site-sp ecific data, that no addi tional monitoring is needed to ensure that the GS project does not pose a risk of endangerment to USDWs, as required at §146.93(b)(3). See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5280 2.8.2.4 USDW non-endangerment demonstrations Comment: (3) Prior to authorization for site cl osure, the owner or operator must demonstrate to the Director, based on monitoring, other site-specific data, and modeling that is reasonably consistent with site performance, that no additional monitoring is needed to assure that the geologic sequestration project does not and is not expected to pose an endangerment to USDWs. The Director shall approve closure if the owner or operator demonstrates, based on the current understanding of the site, including monitoring data and/or modeling, all of the following: (i) the estimated magnitude and extent of the project footprint (CO2
p lume and the area of elevated pressu re) ; (ii) the estimated location of the detectable CO2 plume; (iii) th at there is no significant leakage of either CO2 or displaced formation fluids that is endangering USDWs; (iv) that the injected or displaced fluids are not expected to migrate in the future in a manner that enc ounters a potential leakage pathway into a USDW; (v) that the injection wells at the site completed into or through the injection zone or confining zone are plugged and abandoned in accordance with these requirements; and (vi) any remaining project monitoring wells at the site are be ing managed by a person and in a manner acceptable to the Director.

Response: EPA disagrees that the rule should specify the criteria for setting th e monitoring timeframe. Instead, EPA believes that such de terminations are site-specific and should be described in a project specific post-injection site care and site closure plan. EPA also be lieves that periodic reviews and updates, where necessary, to the plan are important to ensuring that the site continues to be managed effectively and to determine whether shortening the monitoring ti meframe is appropriate. The postinjection site care requirements in the final GS rule offer owners or operators flexibility regarding the duration of the PISC timeframe by: (1) allowing the Director discretion to shorten or lengthen the PISC timeframe during the post-injecti on period based on site-specific da ta, pursuant to requirements at §146.93(b); or (2) affording the Direct or discretion to allow a Class VI well owner or operator to demonstrate, during the permitting pr ocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangermen t of USDWs pursuant to requirements at §146.93(c). EPA believes that a default post-in j ection site care timeframe of 50 y ears, with flexibilit y to ad j ust the Commenter Name: Jeff W. Sheets Letter ID: 0192 Commenter Or g anization: ConocoPhillips Comment ID: 23905timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts. EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and m onitoring wells; perform post-inject ion monitoring; demonstrate the appropriateness of an alternative pos t-injection site care time frame; demonstrate non endangerment; and
p erform site closure activities. The guidance will be available at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions; 1610 1.3.1 Risks to USDWs; 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) Comment: Issue 3. The proposed regulation currently defines USDWs as z ones that contain groundwater with a total dissolved soli ds (TDS) concentration of less than 10,000 mg/L. This limit should be revised to consider geologic strata with water containing higher TDS concentr ations, because these zones may be economic in the future.

The technology for treating high TDS water for use in water supply is improving rapidly, and these high TDS aquifer zones ma y be needed in the future. In areas with limited water resources water pr oviders are beginning to turn to groundwater sources containing in excess of 10,000 mg/L TDS (Sengebush 2008). It is already conceivable that in th e near future sources with up to approximately 20,000 mg/L TDS will be cons idered viable as water treatment technology advances making such wate r sources economical. To protect groundwater resources which may be economical in the foreseeable future the rule should evaluate the potential that curren tly marginal groundwater sources will be usable. The repository zones should be limited to strata containing very high TDS concentrations that siting studies a nd public input indicate are not likely to be useable in the future, as use of a zone for CO2 sequestration will likely
p reclude recovery and use of the gr oundwater resource in the future.

Sengebush, R. M. 2008, INTERA, Inc. Deep Brackish Water Considered for New Mexico Development. Southwest Hydrol ogy, March/April 2008, p. 8. Available from http://www.swhydro.arizona.edu/ar chive/V7_N2/dept-ontheground.pdf.

Response: The Agency acknowledges the commenter’s concer ns about water resources and future water resource availability. However, modifying the definition of a USDW is outside the scope of the GS rulemaking. USDWs are defined as aqui fers currently being used as s ources of drinking water or those capable of supplying a public water system, with a total dissolved solids (TDS) content of 10,000 milligrams per liter or le ss, as specified in §144.3.

The primar y g oal of the UIC Pro g ram under the SDWA is to protect USDWs from endan g erment in Commenter Name: And y Horn Letter ID: 0196 Commenter Or g anization: Colorado Ground Water Association (CGWA) Comment ID: 23923order to ensure a reliable supply of drinking water for the American publ ic. The GS rule, as part of the UIC program regulations implemen ting the SDWA, continues the progr am’s mandate of ensuring the
p rotection of USDWs. EPA expects that the tailored permitting, siting, construction, operation, monitoring, and post-injecti on site care requirements in the GS rule will prevent leakage from injection formations and protect USDWs.

EPA recognizes that ther e is increasing demand for water res ources and that technology improvements may make high TDS aquifers viable drinking water sources. EPA believes these potential resources should be considered when injection depth waivers are sought. Therefore, the final GS rule at §146.95 (b) requires the Director to consider these issues in determining whether an injection depth waiver is appropriate. Specifically, the Direct or must consider whether alternative injection sites are available; community needs, demands, and supply from drinking wa ter resources; planned ne eds, potential and/or future use of USDWs and non-USDWs in the area; and a plan for s ecuring alternative resources or treating USDW formation wate rs in the event of contamination relate d to the Class VI injection activity. For additional information on the waiv er approach, please se e the final rule and preamble, as well as EPA's responses to comments on the Notice of Da ta Availability and Request for Comment.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: We believe that use of the phrase "corr ective action" to desc ribe well plugging and repair risks confusion with the c oncept of corrective action under either RCRA or CERCLA. This potential confusi on can lead to unwarranted negative associations with the phrase "corrective action," and we would suggest abandoning this phrase and instead use a phrase such as "well plugging and repair." We would then also support a phased approach to well plugging and repair ("corrective action") for CO2 GS we lls as contemplated in the Proposal and it should be available to all Owners or Operators of CO2 GS wells rather than be available only at the discre tion of the Director. 73 Fed. Reg. at 43507-08.

Response: EPA notes that the term "corrective action" at §146.84(d) has been used to describe the
p rocess of addressing improperly plugged wells in the AoR of injection wells since the inception of the UIC Program, e.g., at §146.7 and §146.64. While EPA is aw are that the term has a different meaning under RCRA and CERCLA, this has not caused confus ion in the past. The alternative term, "well
p lugging," suggested by the commente r is reserved for injection we ll plugging as indicated at §146.92.

Other EPA Comment Codes and Descriptions: 5700 2.12 Comments on the proposed duration of Class VI permits (seeking comment) Comment: Rule Provision: 144.36(a)

Anadarko Petroleum Corporation (APC) Co mments: (a) Permits for Class I and V wells shall be effective for a fixed term not to exceed 10 years. UIC Permits for Class II AND III and VI wells shall be issued EFFECTIVE for a period up to the operating life of the facility. PERMITS FOR CLASS VI WELLS SHALL BE EFFECTIVE FOR THE PERIOD THROUGH SITE CLOSURE. Commenter Name: Paul Pike Letter ID: 0198 Commenter Or g anization: Ameren Corporation Comment ID: 23948

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24627Rationale: Permits are necessary for Clas s VI wells through the end of the post closure monitoring phase, which is consistent with the term site closure in the amended requirement.

Response: EPA clarifies that the final GS rule specifies that Class VI permits wi ll be issued for the operating life of the facility and th e post-injection site ca re period (144.36(a)). However, it also adds a requirement that the Director review each Class VI permit at least ever y five years to determine whether it should be modified, revoked and reissued, terminat ed, or a minor modificati on made as provided in §§144.39, 144.40, or 144.41. The Director’s review will be informed by the owners’ or operators’ iterative reevaluation of the project . Specifically, the final rule includes a requirement that the AoR be reevaluated at least every five year s, and also requires owners or opera tors to review and update the AoR and corrective action plan, the testing and monitoring plan, and the emergency and remedial response
p lan throughout the life of the project (146.84(e), 146.90(j), and 146.94(d)). Owners or operators must review each plan and identify necessary amendments or demonstrate to the Di rector that no amendment is needed. In no case can reviews occur less often than once every five years. The iterative process and subsequent plan reevaluations ensure that time and resources are committed to the most critical aspects of the permit in preventing endangerment to USDWs.

EPA believes that the iterative process of devel oping and executing the various plans required of GS well operators in the final rule (e.g., for AoR and corrective action, testing and monitoring, well
p lugging, and post-injection site care , and emergency and remedial response) is tailored to the unique aspects of—and is more appropriate for–GS than esta blishing a finite permit dur ation (e.g., five years as suggested by some commenters). This is pref erable to a periodic pe rmit reapplication.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Rule Provision: 146.23(a)

Anadarko Petroleum Corporation (APC) Commen ts: (3) WHEN, ON AN ANNUAL BASIS, THE FIELD-WIDE AVERAGE CO2 INJE CTION TO WITHDRAWAL RA TIO IS GREATER THAN 5.0 IN AN INJECTION ZONE AND THE AVERAGE RESERV OIR PRESSURE IN THE INJECTION ZONE BECOMES GREATER THAN (A) THE AVER AGE ORIGINAL RESERVOIR PR ESSURE IN THE INJECTION ZONE AT THE TIME OF DISCOVERY OF THE RE SERVOIR, OR (B) TH E AVERAGE DESIGN OPERATING PRESSURE DURING CO2 EOR OR EGR, WHIC HEVER IS GREATER, THE DIRECTOR MAY REQUIRE THE OPERATOR OF A CO2 EOR OR EGR PR OJECT PERMITTED UN DER CLASS II TO PROVIDE ADDITIONAL INFORMATION AND DATA TO THE DIRECTOR EXPLAINING THE N ECESSITY TO INCREASE OR MAINTAIN SUCH PRESSURE.

IF THE DIRECTOR DETERMINES, BASED ON SI TE-SPECIFIC CHARACTE RISTICS THAT THE

INFORMATION PROVIDED FAILS TO SUPPORT THE NEED TO INCREASE OR MAINTAIN Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24629THE AVERAGE RESERVOIR PRESSURE IN THE INJECTION ZONE ABOVE THE AVERAGE ORIGINAL RESERVOIR PRESSURE, OR TH E AVERAGE DESIGN OPERATING PRESSURE DURING CO2 EOR OR EGR, THE DIRECTOR MAY RE QUIRE THE OPERATOR TO:

(I) REDUCE OR MAINTAIN THE CO2 EOR OR EGR PROJECT’S FIELD-WIDE AVERAGE INJECTION TO WITHDRAWAL RATIO TO A VALUE SUCH THAT THE AV ERAGE RESERVOIR PRESSURE OR AVERAGE DESIGN OPERATING PRESSURE DURING CO2 EOR OR EGR WITHIN THE INJECTION ZONE ESSENTIALLY REMAINS CONSTANT; OR

(II) APPLY TO RECLASSIFY THE CO2 EOR OR EGR INJECTION WELLS AND INJECTION ZONE COVERED UNDER THE CLASS II PERMIT AS A GEOLOGIC SEQUESTRATION PROJECT REGULATED UNDER THE APPLICABLE WELL CLASS.

IF THE OPERATOR FAILS TO COMPLY WITH ANY OF THE ABOVE REQUIREMENTS, THE DIRECTOR MAY REVOKE OR MODIFY THE APPLIC ABLE CLASS II INJECTION PERMIT.

Rationale: A carbon dioxide stream or car bon dioxide may be injected into a reservoir for EOR or EGR. When CO2 comes in contact with oil it dissolves into the oil, the oil swells, becomes less vi scous and the surface tension between the oil and the formation is reduced to such a point that the oil becomes mobile. The injection of CO2 also raises the pressure in th e formation to a desired or designed operating pressure. If achievable, the desired operating
p ressure will be above the miscibility pressure of th e oil and CO2. Achieving sustained pressures at or above the misc ibility pressure will generally allow the most efficient and effective recovery of the residual oil remaining in the formation. Miscibility pressures are de pendent on the oil properties, carbon dioxide stream properties and the reservoir temperature. T hus, miscibility
p ressure may be less than the average original discovery pressure of the reservoir, or may be equal to or greate r than the average original discovery
p ressure of the reservoir. The propertie s of some oils (generally heavier crudes) are such that the miscibility pr essure of the oil and CO2 is far in excess of the average original discovery pr essure of the reservoir and can even be greater than the fracture pressure of the reservoir and/or the confining

zone.

Once the reservoir pressure reaches the designed or desired average reservoir
p ressure for the CO2 EOR project, the injections of CO2 (or CO2 and water in water alternating gas CO2 EOR projects) are managed such that the volumes of CO2 (or CO2 and water) being injected into th e reservoir are generally equal to, or slightly greater than, the volumes of flui ds being withdrawn from the reservoir such that the average designed or desire d operating reservoir pressure remains relatively constant. The de sired or designed operating re servoir pressure may bealtered from time to time, but the pr ocess of raising the average reservoir
p ressure, and then holding the average reservoir pressure relatively constant, is the same.

Therefore, except during periods of reservoir re-pressurization (i.e. the beginning of a CO2 EOR project, or for a period of time when the designed or desired average reservoir ope rating pressure is being raised), the ratio of the injected volumes (CO2 + water) to the wi thdrawal volumes (CO 2, oil, associated natural gas and water) will most likely be less than 1.5. All volumes should be determined at average reservoir conditions, or, at a minimum, at the same conditions (i.e. same average pr essures and temperatures).

In contrast, a GS project whether occurring after a CO2 EOR project or as a standalone GS project is a project in which the primary, bu t not necessarily only, purpose is to inject and store a CO 2 stream. Therefore, the ratio of injected volumes (CO2) to the withdrawal volumes (CO2 + other formation fluids) should be greatly in excess of 1.5 and more than likely an order of magnitude greater.

In order to allow for reasonable fluctuat ions and variations within CO2-EOR
p rojects an injection-withdraw al ratio of 5.0 (3 to 4 times multiple of typical injection-withdrawal ratios) is recommended to distinguish between CO2- EOR and Geologic Storage projects. The injection- withdrawal ratio should be measured over the applicable reporting period required under the applicable permit and will be evaluated on a field- wide basis compared to a well-by-well basis (which will allow for phased development).

Response: As described above in the response to comm ent 24625 regarding the suggested edit at 144.6, EPA did not make the suggested change. The Agency disagrees that wells injecting CO2 for the primary
p urpose of long-term storage s hould be regulated under Class II requirements because Class II requirements do not address the uni que risks posed by GS to ensu re protection of USDWs from endangerment.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisi ons to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tran sitioning from Class II to Class VI.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Rule Provision: 146.81(b)

Anadarko Petroleum Corporation (APC) Commen ts: (b) This subpart applies to wells used to inject carbon dioxide EXCLUS IVELY for the purpose of geologic sequestration, i.e., the long-term c ontainment of a gaseous, liquid or supercritical carbon dioxide stream in subsurface geologic formations. IT IS RECOGNIZED THAT SOME ACTIVITIES CO NDUCTED UNDER CLASS II, INCLUDING CO2 BASED EOR OR EGR MAY SEQUESTER A PORTION OF THE CARBON DIOXIDE STREAM USED FOR Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24631EOR OR EGR. THIS SUBPART DOES NOT APPLY TO INJECTION OF A CARBON DIOXIDE STREAM FOR PURPOSES OF EOR OR EGR EVEN THOUGH GEOLOGIC SEQUESTRATION OF CARBON DIOXIDE MAY OCCUR DURING OR IN CO NNECTION WITH EOR OR EGR OPERATIONS AND/OR ACTIVITIES.

Rationale: See 144.6

Deleted "gaseous, liquid or supercritical" because it was added to the definition of CO2 stream.

Response: As described above in the response to comm ent 24625 regarding the suggested edit at 144.6, EPA did not make the suggested change. The Agency disagrees that wells injecting CO2 for the primary
p urpose of long-term storage s hould be regulated under Class II requirements because Class II requirements do not address the uni que risks posed by GS while en suring protection of USDWs from endangerment.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisi ons to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tran sitioning from Class II to Class VI.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: Rule Provision: 146.81(c)

Anadarko Petroleum Corporation (APC) Comm ents: (c) ) This subpart applies to owners and operators of permit or ru le-authorized Class I industrial, Class II, or Class V experimental carbon dioxide injection projects who seek to apply for a Class VI geologic sequestration permit for their well or wells. If the Director determines that USDWs will not be endangered, such wells are exempt, at the Director’s discretion, from the casing a nd cementing requirements at §§ 146.86(b) and 146.87(a)(1) through (3).

Rationale: The reference to Class II wells in section 146.81(c) is no longer needed due to addition of 146.25.

However, if EPA were not to adopt section 146.25, APC would suggest the following revisions:

(c) This subpart applies to owners and operators of permit or rule-authorized Class I industrial, Cl ass II WHO HAVE CEASED AND WILL NO LONGER CONTINUE EOR OR EGR OPERATIONS OR ACTIVITIES, or Class V experimental carbon dioxide injection
p rojects who seek to apply for a Class VI geologic sequestration permit for their well or wells. If the Director determines th at USDWs will not be endangered, such wells are exempt, at the Director’s discretion, from the casin g and cementin g requirements at §§ 146.86(b) and 146.87(a)(1) throu g h Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24632(3). CLASS VI REQUIREMENTS. CLASS II W ELLS PERMITTED FOR CO2 INJECTION AND THAT HAVE DEMONSTRATED MIT ARE EX EMPT FROM THE REQUIREMENTS AT §§146.86 AND 146.87.

The language allows for the transition of Class II wells to Class VI operations. These wells should be allowed to inject CO2 for storage based on their history of sound performance under the Class II progr am as demonstrated by MIT results. The language also allows the Director to exercise discretion to exempt other Class VI requirements.

Response: As described above in the response to comm ent 24625 regarding the suggested edit at 144.6, EPA did not make the suggested change. The Agency disagrees that wells injecting CO2 for the primary
p urpose of long-term storage s hould be regulated under Class II requirements because Class II requirements do not address the uni que risks posed by GS while en suring protection of USDWs from endangerment.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisi ons to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach to tr ansitioning from Class II to Class VI.

EPA is developing guidance on transitioning permits from Class II to Class VI. Th e guidance will assist Directors in determining whether an injection project should be transitioned from Class II where the
p rimary purpose is oil and gas production to Class VI where the primary purpose is long-term storage of large volumes of CO2. The guidance describes recommended methods the Director may use to evaluate changes in risk to USDWs from projects, and how the Director may determine whether a project should be regulated within the Class II or Class VI UI C program. This guidance wi ll be available on EPA’s website at http://water.epa.gov/t ype/groundwater/uic/wells_sequestra tion.cfm. For more information,
p lease see the discussion on transiti on of Class II wells in the prea mble to the final GS rule.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(b)

Anadarko Petroleum Corporation (APC) Co mments: (b) A surface map showing the PROPOSED LOCATIONS FOR the injection well(s) for which a permit is sought and the applicable area of review. Within the area of review, the map must show the number, or name and location of all KNO WN injection wells, producing wells, abandoned wells, plugged wells or dry holes , deep STRATAGRAPHIC boreholes, State or EPA approved subsurface cleanup sites, surface bodies of water, springs, mines (surface and subsurface), quarri es, water wells and other pertinent surface features including structures in tended for human occupancy and roads. The map should also show faults, if known or suspected. Only information of
p ublic record is required to be included on this map;

Rationale: Faults are not shown on maps unl ess there is a surface expression of the fault. Also, faults are detailed in (d) below and this lan g ua g e appears Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24641redundant.

Known needs to be added to remove any implication that an applicant has to conduct stuides to determine wells that are not currently documented in some fashion.

Response: Regarding the comment that EPA delete ment ion of faults on surface maps, EPA believes that if faults have surface expressions, they should be presented on maps submitted; this information would complement the required cross section data. EP A is developing guidance on site characterization for GS projects to assist owners or operators and Directors in evaluating permit requirements and applications under §146.82. The guidance provides recommendations regardi ng characterizing the regional geology and hydrogeology of a proposed GS site as well as performing the necessary geochemical, geomechanical, and ge ophysical analyses of the injection and confining zone. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

EPA disagrees that the information that is submitte d to support a Class VI permit application should be limited to known/available data. Th e Agency believes that the site characterization requirements at §146.82, including geomechanical information and geol ogic and topographic maps and cross sections, are essential to proper siting of a GS well and are the foundation for a detailed understanding of the local and regional geology, and that the owner or operato r should collect this information, regardless of whether it is known in advance of the siting process. Collecting and evaluating this data supports important evaluations regarding the suitability of the site to receive and contain injected CO2. Please see the final rule and the discussion of geologic site char acterization in the preamble for additional information.

EPA acknowledges that some smaller fractures may not be detectable during the site characterization
p rocess, and clarifies that §146.82(a)(3 )(ii) requires the owner or opera tor to submit data on known or suspected faults and fr actures (i.e., not all fractures). Other re quirements for GS inje ction wells and sites can mitigate the potential impacts of unidentified fractures. These include li mitations on injection
p ressures to avoid propagation of existing fractures in the confini ng zone (§146.88(a)), collection and assessments of CO2 monitoring data at the site, and Ao R reevaluations (§146.84(e)) to assess possible CO2 movement through high-perm eability regions (i.e., faul ts and/or fractures) not detected in the initial site characterization.

EPA also believes that a determination about whether or what information may be necessary (for a specific GS project) is out side of the public record will be site-specific and based on knowledge of the site, data availability, and data quality. For instance, in meeting the requirement to tabulate information on wells in the AoR, the Director has the discreti on to require the owner or operator to supplement a data records search if there is re ason to believe that the incomplete ness of available information could compromise USDW protection from endangerment.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(c)

Anadarko Petroleum Corporation (APC) Commen ts: (c) A MAP DELINEATING the area of review based on UPON modelin g , usin g ALL AVAILABLE data INCLUDING DATA Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24642obtained during logging and testing of the well and the formation as required by paragraphs (l), (r), and (s) of this section ANY WELLS IN THE AREA OF REVIEW

Rationale: This appears to be related to a condition where a well is already drilled. This does not align with reques ting information to receive a permit.

Response: EPA recognizes that this information may not be available until after a well has been drilled. EPA revised §146.82 so that the final regulation specif ies separate requirements for information to be submitted with the permit applic ation and before well construc tion is approved (at §146.82(a)) and information to be submitted before operation of the well is authorized (at §146.82(c)).

Final information on injection zone pressures would be required. EPA recognizes that this information may not be available until after a well has been drilled. EPA revised §146.82 so that the final regulation specifies separate requirements for information to be submitted with the permit application and before well construction is approved (at §146.82(a)) and information to be submitted before operation of the well is authorized (at §146.82(c)). Final informati on on injection zone pressures would be required following drilling of th e well, at §146.82(c)(4).

In the final rule, the requirement for the final AoR based on mode ling, including data obtained during logging and testing, can be found at §146.82(c)(1). Plea se see the final rule and the discussion of geologic site characterization in the preamble for additional information.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(d)

Anadarko Petroleum Corporation (APC) Co mments: (d) KNOWN information on the geologic structure and hydrogeologic RESERVOIR properties of the proposed storage site and overlying formations, including:

(1) ISOPACH maps and OF THE PROPOSED INJECTION AND CONFINING ZONE(S), A STRUCTURAL CONTOUR MAP HUNG ON THE TOP OF THE PROPOSED INJECTION ZONE, AND AT LEAST TWO GEOLOGIC cross sect ions of the area of revi ew SHOWING THE GEOLOGIC FORMATIONS FROM THE SURFACE TO TOTAL DEPTH.

(2) Location, orientation, a nd properties of known or suspected SUBSURFACE faults and fractures that may transect the confin ing zone(s) in the area of review and a determination that they w ould not interfere with containment;

Rationale: If the information is not known, it cannot be reported.

"Reservoir" and changes to (1) a nd (2) are technical corrections.

Fractures generally can’t be identified until a well is drilled and evaluated. Even then, onl y fractures in the immediate vicinit y of the wellbore can be Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24643identified.

Response: EPA believes that all of the site characterization requirements at 146.82, including information on faults and fractures, are essential to proper siting of a GS well and are the foundation for a detailed understanding of the local and regional ge ology, and that the owner or operator should collect this information, regardless of whether it is know n in advance of the siting process. Collecting and evaluating this data supports importa nt evaluations regarding the suitability of the site to receive and contain injected CO2.

EPA recognizes that this information may not be available until after a well has been drilled. EPA revised §146.82 so that the final regulation specifie s separate requirements for information to be submitted with the permit applic ation and before well construc tion is approved (at §146.82(a)) and information to be submitted before operation of the well is authori zed (at §146.82(c)). Final information on injection zone pressures would be required following drilling of the well, at §146.82(c)(4).

EPA acknowledges that some smaller fractures may not be detectable during the site characterization
p rocess, and clarifies that §146.82(a)(3 )(ii) requires the owner or opera tor to submit data on known or suspected faults and fr actures (i.e., not all fractures). Other re quirements for GS inje ction wells and sites can mitigate the potential impacts of unidentified fractures. These include li mitations on injection
p ressures to avoid propagation of existing fractures in the confini ng zone (§146.88(a)), collection and assessments of CO2 monitoring data at the site, and Ao R reevaluations (§146.84(e)) to assess possible CO2 movement through high-perm eability regions (i.e., faul ts and/or fractures) not detected in the initial site characterization.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision:146.82(d)(3)

Anadarko Petroleum Corporation (APC) Comments: (3) Information on seismic history THAT HAVE AFFECT ED THE PROPOSED AREA OF REVIEW INCLUDING KNOWLEDGE OF PREVIOUS SEISMIC EVENTS AND HISTORY OF THESE EVENTS, including the presence and depth of seismic sources and a determin ation that the seismicity would not interfere with containment;

Rationale: Information on seismic history s hould have some degree of relevance to the project.

Response: EPA believes that consideration of local and regi onal seismicity is important and this type of review is relevant to every proj ect. The site characterization provisions in the GS rule, including a review of the local and regional geology, and detailed review of a ny known or potential seismically active terrain in the vicinity of a proposed GS site are necessary to minimize the potential for induced seismic events or the reactivation of faults, which are a known potential risk associated with injection and are addressed in all aspects of the UIC regulations. Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24644

Commenter Name: Crai g R. Walters Letter ID: 0200Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(d)(4) & (5)

Anadarko Petroleum Corporation (APC) Co mments: (4) Data on the depth, areal extent, thickness, mineralogy, poros ity, permeability and capillary RESERVOIR pressure of the injection and confining zone(s) WITHIN THE AREA OF REVIEW; including geologic/facies changes based on field data which may include geologic cores, outcr op data, seismic surveys, well logs, and names and lithologic descriptions;

(5) KNOWN geomechanical information on fractures, stress, ductility, rock strength, and in situ fluid pressures within the confining zone(s) WITHIN THE AREA OF REVIEW; and

Rationale: Deleted capi llary pressure because it is too hard to measure outside of the lab. Using sidewall cores, it ma y be difficult to determine capillary
p ressure. Additionally, full cores are not available until after the well being
p ermitted is drilled.

Response: EPA acknowledges the comment but did not make the suggested edits. The Agency believes that the site characterizati on requirements at §146.82, including geomechanical information and geologic and topographic maps and cross sections, are essential to proper siting of a GS well and are the foundation for a detailed understanding of the local and regional geology, and that the owner or operator should collect this information, regardless of whet her it is known in advanc e of the siting process. Collecting and evaluating this data supports important evaluations regardi ng the suitability of the site to receive and contain injected CO2.

EPA acknowledges that laboratory met hods are standard for determining capillary pressures regardless of formation permeability and that in situ measurements would require drilling of a well. However, EPA also anticipates that test wells will be drilled to support geologic site characteri zation of the proposed GS sites and can be used to collect subsurface sample s (for laboratory determinati on of capillary pressure) and take other necessary measurements.

EPA recognizes that this information may not be available until after a well has been drilled. EPA revised §146.82 so that the final regulation specifie s separate requirements for information to be submitted with the permit applic ation and before well construc tion is approved (at §146.82(a)) and information to be submitted before operation of the well is authori zed (at §146.82(c)). Final information on injection zone pressures would be required following drilling of the well, at §146.82(c)(4).

EPA believes that information on ca pillary entry pressure is necessary and appropriate. Capillary entry
p ressure measurements on core samples can quantify the amount of buoyant force the confining zone can maintain before failure (Wor ld Resources Institute, 2008).

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions require d for permit applications (seekin g comment) Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24645

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24646Comment: Rule Provision: 146.82(e)

Anadarko Petroleum Corporation (APC) Co mments: (e) A tabulation of all wells ARTIFICIAL PENETRATIONS within the area of review which penetrate the injection or confining zone(s). Such data must in clude a description of each well’s type, construction, date drille d, location, depth, record of plugging and/ or completion, and any additional inform ation the Director may require;

Rationale: Artificial penetrations is a more inclusive term.

Response: EPA agrees that all artificial penetrations must be identi fied and evalua ted during site characterization. However the final rule retains th e proposed text to be c onsistent with similar requirements for other well classes and to support th e corrective action requirements. EPA is developing guidance on AoR and corrective action at GS Class VI sites to assist ow ners or operators and Directors in evaluating requi rements and proposed AoR and correct ive action plans under §146.84. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(f)

Anadarko Petroleum Corporation (APC) Comments: (f) Maps and stratigraphic cross sections indicating the general vertical and lateral limits of all USDWs, water wells and springs with in the area of review, thei r positions relative to the injection zone(s) and the direct ion of water movement, where known; POTENTIOMETRIC (WATER LEVE L) SURFACE MAP(S) OF EX ISTING AQUIFERS BEING UTILIZED AS PRIVATE OR PUBLIC WATER SUPPLIES AND THE DIRECTION OF GROUNDWATER FLOW IN THESE AQUIFERS WITHIN THE AREA OF REVIEW. AT LEAST TWO GEOLOGIC CROSS SECTIONS SHOWING THE THICKNESS AND GENERAL VERTICAL AND LA TERAL LIMITS OF ALL USDWS WITHIN THE AREA OF REVIEW.

N o rationale provided

Response: The Agency acknowledges the suggested edits but has retained the language as proposed. EPA believes that a thorough unde rstanding of the hydrogeologic conditi ons of all USDWs in the AoR is necessary to protect USDWs from endangerment, and disagrees with the suggested edits because the GS rule, as written, affords flexibility to owners or operators and Directors to tailor the site characterization process to the unique geologic features of the site. Th e final requirements will allow for submittal of information similar to or the same as that which was suggested by the commenter. EPA encourages owners or operators and Directors to consult during si te characterization to discuss information needs and ensure that all appropriate data necessary to assess the suitability of the site are collected. The Director may request additional hydrogeologic data or ot her data on USDWs as well, as
p rovided in §146.82(a)(21). Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24647Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(g)

Anadarko Petroleum Corporation (APC) Co mments: (g) Baseline geochemical data on subsurface formations, including all USDWs in the area of review COMPILATION OF AVAILABLE GEOCHEMICA L DATA ON THE PROPOSED INJECTION ZONE AND N EAREST POROUS AND PERMEABLE FORMATION ABOVE THE CONFINING ZONE.

Rationale: Limits the data submitted to available information and to the injection zone and the zone immediately above the confining zone which is the zones most likely to be monito red for potential CO2 leakage.

Response: The Agency acknowledges the suggested edits but has retained the language as proposed. EPA believes that a thorough unde rstanding of the hydrogeologic conditi ons of all USDWs in the AoR is necessary, and disagr ees with the suggested edits because the GS rule, as written, a ffords flexibility to owners or operators and Directors to tailor the site characterization process to the unique features of the site. EPA encourages owners or opera tors and Directors to consult during site characterization to discuss information needs and ensure that all appropriate data necessary to assess the suitability of the site are collected. The Director has the authority to reque st additional hydrogeologic data or other data on USDWs as well.

The Agency believes that the requirement at §146.82( a)(6) to submit baseli ne geochemical data on subsurface geologic formations, including all USDWs in the AoR, is appropriate and protective of USDWs. EPA believes that this data will support monitoring plan development, inform injectate fate and transport model development (e.g., by providing appropriate input parameters), and provide information needed to respond to any unexpected a nd unpermitted leaks outside of the injection zone. The baseline geochemical informat ion will allow the owner or opera tor and permitting authority to evaluate monitoring data and identify any changes in subsurface geochemistry that may indicate fluid
movement.

The rule requires geochemical analysis of, at a minimum, the injection zone, confining zone, and all USDWs (§146.82(a)(6)). These geochemical tests are necessary to ensure the adequacy of the confining system and to serve as a baseline for future m onitoring. The Director has the discretion to require geochemical analysis of additional subsurface zones if, in the Dir ector's opinion, they are necessary for the protection of USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82); 4710 2.7.1 Propos ed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(h)

Anadarko Petroleum Corporation (APC) Co mments: (h) Proposed operating data: (1) Average and maximum daily INJECTION rate and volume of the carbon dioxide stream; (2) Avera g e and maximum SURFACE in j ection pressure; Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24648

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24649Rationale: Technical clarifications.

Response: EPA disagrees that the suggested technical clarificati ons are necessary. EPA adds that it is developing guidance for owners or operators on the ge ologic site characterization process. The guidance will provide recommendations for owners and ope rators to consider when completing a permit application. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82); 4710 2.7.1 Propos ed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(n)

Anadarko Petroleum Corporation (APC) Comments: (n) A WELLBORE schematic or other appropriate drawings of the surface and of the subsurface construction details of the well AND SURFACE WELLHEAD CONSTRUCTION.

Rationale: Technical clarification.

Response: EPA disagrees that the suggested technical clarificati ons are necessary. EPA adds that it is developing guidance for owners or operators on the ge ologic site characterization process. The guidance will provide recommendations for owners and ope rators to consider when completing a permit application. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82); 4710 2.7.1 Propos ed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(q)

Anadarko Petroleum Corporat ion (APC) Comments: q) The ANY status of corrective action on wells in the area of review;

Rationale: Clarifies that wells not need ing corrective action will not have a corrective action status.

Response: EPA disagrees that the suggested technical clarificati ons are necessary. EPA adds that it is developing guidance for owners or operators on the geologic site characterization and AoR and corrective action process. The guidance documents will provide recommendations for owners and operators to consider when completing a perm it application. The guida nce can be found on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm.

Other EPA Comment Codes and Descriptions: 3110 2.1.1 Proposed sitin g requirements (i.e., Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24650

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24651

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24652injection/confining zone s, trapping mechanism) Comment: Rule Provision: 146.83(a)(2)

Anadarko Petroleum Corporation (APC) Comm ents: (2) A confining zone(s) that is LATERALLY CONTINUOUS AND free of KNOWN TRANSECTING, transmissive faults or fractures and of sufficient areal extent and integrity to contain the injected carbon dioxide stream and displaced form ation fluids and al low injection at
p roposed maximum pressures and volume s without initiati ng or propagating fractures in the confining zone(s); and OVER AN AREA SUFFICIENT TO PREVENT THE MOVEMENT OF INJECTED OR DISPL ACED FLUIDS INTO A USDW;

Rationale: The proposed clarification k eeps the emphasis on the non-endangerment of USDWs and limits the requirements to that which is known or can be readily determined.

Response: The Agency believes that the requirement at §146.83(a)(2) that the confining zone be free of transmissive faults or fractures is appropriate for Class VI well s and is necessary to ensure containment of the injectate and that requiring the confining z one to be free of transmissive faults maximizes
p rotection of USDWs from endangerment. EPA believes that the text regarding propagation of faults and fractures is important to avoid the potential for fluid movement and to ensure that injection is at appropriate pressures. Class I hazardous waste injection well operators must also meet a similar requirement that the site is free of transmissive faults or fractures; they have successfully made such demonstrations in the past. While core samples obt ained through drilling and hydr aulic testing are direct methods to obtain such informati on, geophysical techniques such as seismic or electromagnetic surveys can also be used in many geologic settings to demonstrate the absence of or identify and characterize the
p resence of faults or fractures. EPA adds that the Di rector must evaluate all geologic data on the site to ensure protection of USDWs from endangerment before approving a site for a GS project.

Other EPA Comment Codes and Descriptions: 3120 2.1.2 Need to identify additional confining and containment zones (seeking comment) Comment: Rule Provision: 146.83(b)

Anadarko Petroleum Corporation (A PC) Comments: (b) At the Director ’ s discretion, owners or operators of Class VI wells must identify and characterize additional zones that will impede vertic al fluid movement, are free of faults and fractures that may interfere with containment, allow for pressure dissipation, and provide additional opport unities for monito ring, mitigation and remediation.

Rationale: This paragraph creates a presumption that additional confining zones WILL be required. It is also redunda nt given the previous sections.

Response: EPA clarifies that secondary confining zones are not require d for all GS sites. Rather, secondary confining zones are required when the Director determines that these zones are needed to maximize the protection of USDW s from endangerment. EPA retains the requirement to identify additional containment/confining zones, if required by the Director, as proposed (e.g., §146.83(b)). EPA believes that, in some situations, the presence of additional confining and c ontainment zones above the
p rimar y (i.e., lowermost) confinin g zone can improve USDW protection. These la y ers could further Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24653impede vertical fluid movement a nd allow for pressure dissipation, and also provide additional sites for monitoring, mitigation, and remediation.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(a)

Anadarko Petroleum Corporation (APC) Comm ents: (a) The area of review is the region surrounding the geologic sequestrati on project that may be impacted by the injection activity. The area of review is base d on computational modeling that accounts for the physical and chem ical properties of all phases of the injected carbon dioxide stream. SUBSURFACE THREE-DIME NSIONAL EXTENT OF THE CARBON DIOXIDE PLUME, ASSOCIATED PRESSURE FRONT, AS WELL AS THE OVERLYING FORMATIONS AND SURFACE AREA AB OVE THAT DELINEATED REGION.

Rationale: Edits make this provision consis tent with the definition of "Area of Review", which was revised.

Response: EPA disagrees that the AoR definition needs to specifically include th e overlying formations and surface area above the delineated region. The intent of the Ao R, a long-standing concept within the UIC Program, is to delineate the surface area and all subsurface formations below it that may potentially be impacted by injection activity. A cceptable delineation models will provide predictions of CO2 fate and transport, as well as changes in formation pressu re, in three dimensions as a function of time that can be used to delineate the subsurface storage site and the AoR. Although EPA disagrees with the commenter's suggested change, the Agency has carefully considered all comments on the AoR definition at 146.84(a) and modified it to read as follow s: The region surrounding th e geologic sequestration
p roject where USDWs may be endangered by the injection activity. The area of review is delineated using computational modeling that accounts for the physical and chemical properties of all phases of the injected CO2 stream and is based on available site characterization, monitoring, and operational data. EPA believes that this definition is sufficiently br oad and describes both the intent of the computational modeling and the relationship of the AoR to areas that are subject to the risks as sociated with injection.

Other EPA Comment Codes and Descriptions: 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(b)

Anadarko Petroleum Corporation (APC) Comm ents: (b) The owner or operator of a Class VI well must prepare, maintain, and comply with a plan to delineate the area of review for a proposed geol ogic sequestration project, periodically reevaluate the delin eation, and perform corrective action that meets the requirements of this section and is IN A MANNER AND AT A FREQUENCY acceptable to the Director. As a part of the permit application, for approval by the Director the owner or operator must submit an area of review and corrective action plan th at includes the followin g information: Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24654

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24655Rationale: Clarification.

Response: EPA disagrees with the suggested changes and be lieves the proposed text is clear as written. EPA believes that review and approval of the AoR and corrective action plan, including the reevaluation frequency of at least every five ye ars, by the Director (and in the c ontext of all inform ation submitted by the owner or operator with the pe rmit application) is important to ensuring USDW protection.

Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment); 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(b)(2)

Anadarko Petroleum Corporation (APC ) Comments: (i) The minimum fixed frequency, not to exceed 10 years, the ow ner or operator proposes to reevaluate the area of review;

(ii) The monitoring and ope rational conditions that w ould warrant a reevaluation of the area of review prior to the next scheduled reevaluati on as determined by the minimum fixed frequency establishe d in paragraph (b)(2)(i) of this section.

(iii) (i) How monitoring and operational data (e.g., injection rate and
p ressure) will be used to inform an area of review re evaluation; and

N o rationale provided

Response: EPA believes that periodic AoR re evaluation at a set frequency of at least every five years is necessary to ensure protection of USDWs from endang erment and address the un certainties inherent in
p redictive modeling. Periodic AoR reevaluations at §146.84(e) ensure that a deliberate effort is made to verify, based on monitoring and operational data, that the CO2 plume is moving within the subsurface as
p redicted. EPA believes that less frequent reevaluations may not be su fficient to appropriately model
p lume and pressure front movement , establish conditions for corrective action, and ensure protection of USDWs from endangerment.

EPA clarifies that if site monitoring data agrees with the existing AoR delineation, a model recalibration may not be necessary, and the AoR reevaluation may consist of a demonstration that the current AoR delineation is adequate base d on site monitoring data.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action; 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(b)(2)(iv)

Anadarko Petroleum Corporation (APC) Comments: (iv II) How corrective action will be conducted to meet the requirements of paragraph (d) of this section, includin g what corrective action will be performed prior to in j ection and what, Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24656

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24657if any, portions of the area of review will have corrective action addressed on a phased basis and how the phasing will be determined; how corrective action will be adjusted if there are changes in the area of review; and how site access will be guaranteed ARRANGED for future corrective action.

Rationale: Future access cannot be guaranteed for an area in advance that may not even be within the boundaries of the AOR/ project.

Response: The purpose of the corrective action requirement at §146.84(d) is to ensure that all wells in the AoR that have the potential to cause the movement of CO2 or other fluids into or between USDWs receive appropriate correctiv e action. In general, to meet this re quirement, the owner or operator will most likely need to obtain the right of access to wells that may require corrective action, and demonstrate they have done this in their proposed Ao R and corrective action plan. The final rule retains the requirement as proposed.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(c)(1)

Anadarko Petroleum Corporation (APC) Comm ents: (1) Predict, using computational modeling, the projected late ral and vertical migrati on of the carbon dioxide
p lume and formation fluids in the subsur face from the commencement of injection activities until the plume movement ceases, pressure differentials sufficient to cause the movement of injected fluids or formation fluids in to a USDW are no longer present, or after FOR a fixed time period as determined by the Director. The model MODELING must:

Rationale: Clarification

Response: Based on an evaluation of all comments received, EPA has clarified this language in the final rule at 146.84(c)(1). It now reads, “Predict, us ing existing site characterization, monitoring and operational data, and computational modeling, the projected lateral and vertical migration of the carbon dioxide plume and formation fluids in the subsurf ace from the commencement of injection activities until the plume movement ceases, until pressure diff erentials sufficient to cause the movement of injected fluids or formation fluids into a USDW ar e no longer present, or until the end of a fixed time
p eriod as determined by the Director.”

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(c)(1)(i) & (ii)

Anadarko Petroleum Corporation (APC) Comm ents: (i) Be based on detailed geologic data collected to characterize the in jection zone, confining zone and any additional zones ; and anticipated operating data, including injection
p ressures, rates and total volumes over the proposed life of the g eolo g ical Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24658

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24659sequestration project THE DURATION OF INJECTION;

(ii) Take into account any RELEVANT geologic heter ogeneities, AND data quality, and their possible impa ct on model predictions; and

Rationale: Clarification.

Response: EPA agrees that detailed geologic data is i nvaluable to modeling an accurate AoR. EPA clarifies that owners or operato rs may use existing data as well as data collected during site characterization to predict the AoR. The final ru le retains the language in §146.84(c)(1)(i) as proposed, and modifies §146.84(c)(1)(ii) slightly to require owners or operators to take into account “other discontinuities” in addition to geologic he terogeneities when predicting the AoR.

EPA disagrees that only the injection and confini ng zones should be included in AoR modeling of GS sites. EPA believes that the modeling should also take into account the possibility of displaced fluids or brines caused by a lateral and/or ve rtical pressure plume, and theref ore it may be necessary to include additional zones along with the confin ing/injection zones to ensure the integrity of the confining zone and ultimately protect a US DW from endangerment.

Other EPA Comment Codes and Descriptions: 3420 2.2.2.1 Scope of the inventory process (e.g., reliance on publicly available in formation, depth of wells) Comment: Rule Provision: 146.84(c)(2)

Anadarko Petroleum Corporation (APC) Comm ents: (2) Using methods approved by the Director, identify all KNOWN ARTIFICIAL penetrations INTO THE CONFINING ZONE, including active and abandone d wells and underground mines, in the area of review that may penetrate the confining zone. Provide a description of each well’s type, construction, date drille d, location, depth, record of plugging and/or completion, and any additional info rmation the Director may require; and

Rationale: Changed for consistency with earlier language.

Response: EPA is retaining the requirement as proposed. EPA agrees with commenters that, for most GS sites, relying on database and ot her public records searches (i.e., of "known" artificial penetrations) will be sufficient to meet the requirements at §146.84(c)(2). However, the Agency recognizes that there may be situations where additional surveys or research to locate wells may be appropriate. For example, there may be cases where the Dire ctor may determine that ground or airborne surveys for wells are appropriate, e.g., if there is reason to believe, based on knowledge of the site or of available data, that the incompleteness of information on known well s could compromise USDW protection from endangerment. In order to preserve the Director's discretion to re quire an operator to supplement a records search, EPA did not make the suggested cha nge. EPA adds that all corrective action must be
p erformed pursuant to the approved AoR and correct ive action plan, which affords the Director the discretion to require any additional information need ed (including information that is not publically available) to ensure that all nece ssary corrective action is performed. Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24660

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24661Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: Rule Provision: 146.84(c)(3)

Anadarko Petroleum Corporation (APC) Co mments: (3) Determine which abandoned wells IDENTIFIED IN 146.84 (C) (2) in the area of review have been plugged (as required by §146.92) in a manner that prevents the movement of carbon dioxide or associated FORMATION fluids that may endanger USDWs.

Rationale: Remove as redundant.

Response: EPA clarifies that the term "associated fluids" as proposed in §146.84(c)(3) refers to formation fluids, other injectates, et c. that may be present in the subs urface and affect movement of the CO2 plume and/or pressure front. EPA believes this terminology woul d incorporate any fluids in the subsurface that could potentially move through artificial penetrations and affect USDWs. EPA has revised the language at §146.84(c)(3) to read, "... ca rbon dioxide or other fl uids that may endanger USDWs..." EPA disagrees that deleting the term area of review is necessary and has retained the term in the final rule language.

Other EPA Comment Codes and Descriptions: 3460 2.2.2.3 Acceptable correct ive action techniques for GS sites (e.g., cements) Comment: Rule Provision: 146.84(d)

Anadarko Petroleum Corporation (APC) Commen ts: (d) Owners or operators of Class VI wells must perform corrective action USING MATERIALS SUITABLE FOR USE WITH THE CARBON DIOXIDE STREAM AND FORMATION FLUIDS, on all wells in the area of review IDENTIFIED IN 146.84(C)(2) that are determined to need corrective action". using methods necessary to prev ent the movement of fluid into or between USDWs including use of corr osion resistant materials, where appropriate.

Rationale: Experience with CO2 based EO R strongly supports the use of many conventional materials that might not meet the technical definition of "corrosion resistant".

Response: EPA revised the text at §146.84(d) to require the use of materials that are "compatible with the carbon dioxide stream." EPA beli eves this language change addresses commenters' concerns and is also consistent with other language regardi ng materials requirements in the GS rule.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: Rule Provision: 146.84(e)

Anadarko Petroleum Corporation (APC) Co mments: (e) If monitoring data indicate an endangerment to USDWs, the owner or operator must notify the Director and cease operations as required by § 146.94. Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24662

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24663Rationale: This is not needed if §146.94 already specifies the notification and cessation of injection. APC suggests th e removal of this language as unnecessarily duplicative.

Response: Based on consideration of all public comments and other information, EPA deleted this
p rovision from §146.84. The final rule now contains a provision in §146.91(c) that requires the owner or operator to report within 24 hours any evidence that th e carbon dioxide stream or associated pressure front may cause an endangerment to a USDW. EPA believes this change consolidates reporting requirements in one place and provides additional clarity.

Other EPA Comment Codes and Descriptions: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) Comment: Rule Provision: 146.84(f)

Anadarko Petroleum Corporation (APC) Comments: (f) At the minimum fixed frequency, not to exceed 10 years, as spec ified in the APPROVED area of review and corrective action plan, or when monitoring and operational conditions warrant, owners or operators must:

Rationale: Clarification.

Response: EPA did not make the suggested change, but ag rees that AoR reevaluations must take place as specified in approved AoR and co rrective action plan. EPA clarifies that owners or operators must develop, implement, and update a Director-approved AoR and correcti ve action plan as required under §146.84(b). EPA is developing guidance for owners or operators on how to pr epare the required GS
p roject plans. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(f)(4)

Anadarko Petroleum Corporation (APC) Comm ents: (4) Submit an amended area of review and corrective action plan or demonstrate to the Director through monitoring data and modeling results that no amendment CHANGE to the area of review and corrective action plan is needed.

Rationale: Clarification.

Response: EPA disagrees with the suggested change and believes the proposed text is clear as written. For additional information on EPA's approach to AoR and corrective action, please see the final rule and
p reamble. Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24664

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24665

Commenter Name: Crai g R. Walters Letter ID: 0200Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Rule Provision: 146.85(a)(1)

Anadarko Petroleum Corporation (APC) Co mments: (1) The Director receives WELL PLUGGING REPORT IDENTIFI ED IN 146.92(D) and approves OR COMPLETION OF the completed post-injection site care and si te closure plan as appropriate ; and

Rationale: Maintenance of the well pl ugging financial obligation until site closure is not necessary. The Director s hould have the authority to release the obligation once the well is plugged.

Response: EPA will allow owners or operators to use se parate financial respons ibility instruments for different GS activities as long as they are able to demonstrate that their instruments will protect USDWs from endangerment. This means that owners or operators must demonstrate adequate financial responsibility for all required activities, including well plugging, with their permit application, per §146.82(a)(14). In addition, on an annual basis, the owne r or operator must adjust the cost estimate for inflation, increase or decrease the value of the fina ncial instrument to match the cost estimate, and
p rovide any updated informat ion related to their financial responsib ility instrument(s), or at any other time deemed appropriate by the Director. These annual reviews provide a mechanism for revising cost estimates up or down to account for changes in the project, including the exec ution of environmental obligations as phases of a GS project are completed.

Regarding the suggested edit at §146.85(a)(1), EPA clar ifies that the owner or operator may be released from a financial instrument when the phase of th e project for which the instrument was required is complete and all financial obligations for that instrument have been met, as specified in §146.85(b)(2). For example, when the injection we ll is plugged to the Director's satisfaction, the owner or operator's financial instrument will be re leased if it was not used.

EPA is developing guidance on financial responsibility for Class VI wells. The guidance will include a discussion on how best to estimate costs to assist GS well owners or operators, third party insurers or
p roviders of financial instrument s, and permitting authorities in developing estimates of the costs associated with various GS activities. Th e guidance is available on EPA's website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Rule Provision: 146.85(b)

Anadarko Petroleum Corporation (APC) Comm ents: (b) The owner or operator must
p rovide to the Director, at a frequency determined by the Director, BUT NO MORE THAN ANNUALLY, written updates of adjustment s to the cost estimate to account for any amendments CHANGE to the area of review and corrective action plan (§146.84), the injection well plugging plan (§146.92), and the post-injection site care and site closure plan (§146.93). Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24666

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24667Rationale: Updates more frequent than annual is not justified.

Response: Cost estimates must be reevaluated after ame ndments to the area of review and corrective action plan, prior to well plugging or site closure, after amendments to the emergency and remedial response plan, or at any other time deemed appropriate by the Director. The rule will also require annual adjustments to the cost estimates for inflation, as specified in §146.85(c)(2). These annual reviews
p rovide a mechanism for revising cost estimates up or down to account for changes in the project, including the execution of environm ental obligations as phases of a GS project are completed.

EPA did not make the proposed edits at §146.85(b), but did extensively revise and clarify the financial responsibility requirements. See the final GS rule and preamble for additional information on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Rule Provision: 146.85(c)

Anadarko Petroleum Corporation (APC) Comm ents: (c) The owner or operator must notify the Director of adverse fina ncial conditions such as bankruptcy , that may affect the ability to carry out in jection well plugging and post-injection site care and site closure.

Rationale: Clarification.

Response: EPA did not make the proposed edits at §146.85(c), but did extensively revise and clarify the financial responsibility requirements. EPA believes that the Director must be notified of bankruptcy specifically, among other adverse financial conditions, because it affects the use of financial instruments. See the final GS rule and preamble fo r additional information on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5432 2.9.1.1 Need to adjust financial responsibility mechanisms (seeking comment) Comment: Rule Provision: 146.85(d)

Anadarko Petroleum Corporation (APC) Comm ents: (d) The operator must provide an adjustment of the cost estimate to the Director if the Dir ector has reason to believe that original THE MOST RECENT demonstrati on is no longer adequate tocover the cost of injection well plugging (as required by §146.92) and postinjection site care and site closure (as required by §146.93)

Rationale: Clarification.

Response: EPA agrees that it is important to periodical ly update cost estimate s that support financial responsibility determinations. EP A clarifies that the GS rule, at §146.85(e), requires the owner or operator to provide annual updates to the cost estima te to account for any amendments to the AoR and corrective action plan, the in j ection well plu gg in g plan, and the PISC an d site closure plan. Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24668

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24669Other EPA Comment Codes and Descriptions: 3800 2.3 Proposed Injection Well Construction Requirements ( 40 CFR 146.86) Comment: Rule Provision: 146.86(a)(1)

Anadarko Petroleum Corporation (APC) Commen ts: (1) Prevent the movement of fluid into or between USDWs or into any unauthorized zones; CONTAINING ANY CONTAMINANT INTO UNDERGROUND SOUR CES OF DRINKING WATER, IF THE PRESENCE OF THAT CONTAMINANT MAY CAUSE A VIOLATION OF ANY PRIMARY DRINKING WATER REGULATION UNDER 40 CFR PART 142 OR MAY OTHERWISE ADVERS ELY AFFECT THE HEALTH OF PERSONS.;

Rationale: The proposed changes reflect the nonendangerment standard that is the basis of the UIC program.

Response: EPA disagrees that the language provide d in § 146.86(a)(1) does not meet the nonendangerment standard provided unde r the SDWA. In fact, EPA believ es that protection of USDWs from endangerment and prevention of fluid movement between formations is paramount and believes that the language as proposed meets the non-enda ngerment standard. Appropriately designed and constructed wells are necessary to prevent endangerment to USDWs and maintain integrity of the well throughout the lifetime of a GS project. This is the foundation of the requirements for construction and
p re-operational testing of Clas s VI wells at §§146.86 and 146.87.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revi sions to the GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3860 2.3.3 Well component degradation Comment: Rule Provision: 146.86(b)(1)

Anadarko Petroleum Corporation (APC) Comm ents: (1) Casing and cement or other materials used in the construction of each Class VI well must have sufficient structural strength and be designed fo r the operating life of the geologic sequestration project WELL. All well materials must be compatible SUITABLE FOR USE with the fluids with which the materials may be expected to come into contact and meet or exceed TEST standa rds OR PRACTICES developed for such materials by the American Petroleum Institut e, ASTM International, or comparable standards acceptable to the Director. The casing and cementing program must be designed to prevent the movement of fluids into or between USDWs. In order to allow the Director to determine and sp ecify casing and cementing requirements, the owner or operator must provide the following information:

Rationale: The life of a geologic sequestra tion project could be different than the life of the well . Class VI well desi g n should be based on the life of the Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24670

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24671well.

Response: EPA disagrees that the casing, cement, or ot her materials should only be designed for the
p eriod of the injection process, ra ther than the life of the seques tration project. GS projects are anticipated to have long life spans in comparison to other types of deep injection wells. Not only must Class VI wells be able to function sa fely and properly over the lifespan of the GS project, but they must b e constructed such that USDWs remain protecte d after well plugging. The requirements at §146.86 will ensure that the well can maintain integrity thr oughout the proposed life span of the project, including after the injection well is plugged and through the post-injection site care period and beyond. While the risk profile of a GS site will decrease following cessation of inje ction, EPA believes that Class VI wells must be designed to protect USDW s from endangerment for the life of the project. Furthermore, rigorous casing and cementing help ensure that the Class VI well will not serve as a conduit for movement of fluids associated wi th future injection operations.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements (seeking comment) Comment: Rule Provision: 146.86(b)(1)(v)

Anadarko Petroleum Corporation (A PC) Comments: (v) Corrosiveness COMPOSITION of the carbon dioxide stream and formation fluids;

Rationale: There is no method for measur ement of "corrosive ness" of a CO2 stream. The relevant information is the composition of the CO2 stream.

Response: The suggested revision to refer to CO2 "compos ition" would be less precise. EPA clarifies that, although corrosiveness does not have a unit of m easure, corrosiveness can be technically measured and described. Procedures that can identify corrosion (or the absence of corrosion) in a Class VI well
p rovide valuable operational information that the Dir ector needs to determine appropriate standards for the tubing and packer.

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3860 2.3.3 Well component degradation Comment: Rule Provision: 146.86(b)(1)(vi)

Anadarko Petroleum Corporation (APC) Comm ents: (vi) Down-hole temperatures AND PRESSURES;

Rationale: Technical clarification

Response: EPA clarifies that information on down-hole pressures is require d at §146.86(b)(1)(ii). Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24672

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24673Other EPA Comment Codes and Descriptions: 3860 2.3.3 Well component degradation Comment: Rule Provision: 146.86(b)(1)(viii)

Anadarko Petroleum Corporation (APC) Comm ents: (viii) Type or grade of cement AND ADDITIVES; and

Rationale: Technical clarification.

Response: EPA agrees with the suggestion that §146.86(b)(1 )(viii) be revised to also address cement additives. In the final GS rule, the subparagraph read s as follows: "Type or gr ade of cement and cement additives."

Other EPA Comment Codes and Descriptions: 3822 2.3.1.1 Depth of surface casing (seeking comment) Comment: Rule Provision: 146.86(b)(2)

Anadarko Petroleum Corporation (APC) Co mments: (2) Surface casing must extend through the base of the lowermost USDW ABOVE THE INJECTION ZONE and be cemented to the surface.

Rationale: In some parts of the US the USDW is very deep and this standard may
p reclude geologic sequestra tion in these areas.

Response: EPA disagrees with the suggested edit. As de scribed above, EPA disagrees that the surface casing requirements in the GS rule preclude injection below deep USDWs. EPA also recognizes concerns regarding construction of Class VI wells wh ere the lowermost USDW is very deep. To further address comments on deep injection wells, the final GS rule at §146.95 includes requirements for owners or operators that seek a waiver of the injection depth requirements. Owne rs or operators of wells operating under injection depth waivers must comply with additiona l construction requirements to ensure that wells used to inject a bove or between USDWs are protective.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: Rule Provision: 146.86(b)(3)

Anadarko Petroleum Corporation (APC) Co mments: (3) At least one long string casing, using a sufficient number of cen tralizers TO CREATE A CEMENT BOND THROUGH THE INJECTION AND CONFINING ZONE(S ), must extend to the injection zone and must be cemented ISOLATED by circulating ceme nt to the surface in one or more stages. PLACING CEMENT AND/OR OTHER ISOLATION TECHNOLOGIES AS N ECESSARY TO PROVIDE ADEQUATE ISOLATION OF THE INJECTION ZONE AND PROVIDE FOR PROTECTION OF USDWS. Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24674

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24675

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24676Rationale: Cementing to surface is not nece ssary to protect USDWS, and may have negative consequences, as follows. Cement to surface would eliminate the ability to monitor pressures in th is annulus and would limit flexibility of remedial options. As revised, the propos al would allow for applicat ion and development of alternative technologies. See API RP90 for description of risk-based approach for managing situations involving annular casing pressure. Industry experience with CO2 EOR under the class II program demonstrates the ef fectiveness of existing cementing procedures.

Response: EPA disagrees with the suggested edits. EPA be lieves that the require ments for long-string casing are appropriate and offer appropriate flexibility: §146.86(b)(3) requires that the long-string casing extend to the injection zone and be cemented by circulating cement to the surface in one or more stages. It does not, however, specify how cementing would be accomplished, and gives fl exibility to the owner or operator to propose altern ate methods to provide a sufficient am ount of cement to meet the standard that USDWs are protected from endangerment, subject to the approva l of the Director.

EPA stresses that protection of US DWs is the primary mission and ma ndate of the UIC program and the
p urpose of all requirements for injection wells. A ny injection activity must be demonstrated to not endanger USDWs, regardless of their depth, and if such non-endangerment cannot be shown, then the activity will not be allowed under UIC requirements or the SDWA.

EPA does not believe that the cementing require ments at §146.86 would prevent monitoring, operation, and remediation of Class VI wells. Cementing of deep wells has been performed successfully in the past by owners or operators of Class I hazardous and Class I municipal waste disposal wells. Some of these wells, which must meet the same cementing and ca sing requirements as Class VI wells, are up to 12,000 feet deep and have been successf ully cemented in a manner that main tains integrity and allows for all required well testing, op eration, and remediation (EPA, 2001). S ee the discussion of Class VI well construction requirements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://wat er.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: Rule Provision: 146.86(b)(4)

Anadarko Petroleum Corporation (APC) Co mments: (4) Circulation of cement may be accomplished by staging. The Director may approve an alternative method of cementing in cases where the cement cannot be recirculated to the surface,
p rovided the owner or operator can demonstrate by using logs that the cement does not allow fluid moveme nt behind the well bore.

Rationale: Same as above

Response: EPA disagrees that the requirement should be deleted. Section 146.86(b)(4) of the final rule allows alternate methods of staging the cement, at the Director's discretion, provided the owner or operator can demonstrate using logs that the cemen t does not allow fluid movement behind the wellbore. Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24677See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: Rule Provision: 146.86(b)(5)

Anadarko Petroleum Corporation (APC) Comm ents: (5) Cement and cement additives must be compatible SUITABLE FOR USE with the carbon dioxide stream and formation fluids and of su fficient quality and quantity to maintain integrity over the design OPERATING life of the ge ologic sequestration project WELL. The integrity and location of the cement shall be verified using technology capable of evaluating cement quality radially and identifying the location of channels to ensure that USDWs are not endangered.

Rationale: Experience with CO2 EOR under th e class II program demonstrates the effectiveness of existing cementing materials and procedures. Standard API cements have been used in numerous CO2 EOR operations with no adverse consequences. Refer to the citations wi thin EPA’s proposed rule 73 FR 43532- 43533: Carey et al., (2007), Crow et al., (2008), and Meyer, J.P (2007).

Response: EPA disagrees with the suggested edits. EPA disagrees that the casing, cement or other materials should only be designed for the period of the injection process, rather than the life of the sequestration project. GS projects are anticipated to have long life span s in comparison to other types of deep injection wells. No t only must Class VI wells be able to function safely an d properly over the lifespan of the GS project, but they must be constructed such that USDWs remain protected after well
p lugging. The requirements at §146.86 will ensure that the well can maintain integrity th roughout the
p roposed life span of the projec t, including after the injection well is plugged and through the postinjection site care period and beyond. While the risk profile of a GS site will decrease following cessation of injection, EPA believes that Class VI wells must be designed to protect USDWs from endangerment for the life of the pr oject. Furthermore, rigorous casing and cementing help ensure that the Class VI well will not serve as a conduit for movement of fluids associated with future injection operations.

EPA recognizes that the oil and gas industry has decades of expe rience injecting CO2 and has demonstrated the effectiveness of existing cementi ng materials and procedures. The final GS rule, at §146.86(b)(1), specifies that all casing and cementing or other materials used in the construction of Class VI wells must meet or excee d standards developed for such ma terials by the American Petroleum Institute, ASTM International, or comparable stan dards acceptable to the Director. This requirement invokes the expertise of these bodies to ensure that the requirements for construction of Class VI wells reflect the state of the art in well construction technology. Se e the discussion of Class VI well construction requirements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://w ater.epa.gov/type/groundwater/u ic/wells_sequestration.cfm.

EPA also believes that GS is sufficientl y different from Class II ER operations to warrant the tailored Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24678construction requirements for Class VI wells at §146.86. For example, th e volume of CO2 anticipated to be injected in Class VI wells is significantly greater than for Cl ass II wells. Reservoir pressure conditions will be different, with Class VI inje ction operations involving la rge volumes of CO2 and likely having higher pressures within their storage formations than Cla ss II ER projects. Therefore, Class VI GS reservoir pressures will increase during the injection phase of the GS project.

Other EPA Comment Codes and Descriptions: 3826 2.3.1.3 Packer requirements (seeking comment) Comment: Rule Provision: 146.86(c)(2)(ii)

Anadarko Petroleum Corporation (APC) Comm ents: (ii) Composition of the carbon dioxide stream. (chemical content, corr osiveness, temperature, and density);

Rationale: There is no method for measur ement of "corrosive ness" of a CO2 stream. The relevant information is th e composition of the CO2 stream. The composition of the CO2 str eam is more relevant to the design of a tubing and
p acker system.

Response: As written, the text at §146.86(c)(3)(ii) accounts fo r all characteristics of the CO2 that could affect the performance of the tubing and packer , including the chemical content, corrosiveness, temperature, and density. The suggest ed revision to refer to CO2 "composition" would be less precise. EPA clarifies that, although corrosiveness does not have a unit of measure, corrosiveness can be technically measured and described. Procedures that can identify corro sion (or the absence of corrosion) in a Class VI well provide valu able operational information that the Director needs to determine appropriate standards for the tubing and packer.

The final GS rule at §146.86(c)(1) also requires that tubing materials used in Class VI wells must meet or exceed standards developed by the American Petrol eum Institute, ASTM International, or comparable standards acceptable to the Director. EPA believes that this requireme nt invokes the expertise of these bodies without the added burden of a certification program.

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3826 2.3.1.3 Packer requirements (seeking comment) Comment: Rule Provision: 146.86(c)(2)(iii) - (v)

Anadarko Petroleum Corporation (APC) Comm ents: (iii) MAXIMUM PR OPOSED Injection temperature and pressure; (iv) MAXIMUM PROPOSED Annular pressure; (v) MAXIMUM PROPOSED Injection rate (intermittent or conti nuous) and volume of the carbon dioxide stream;

Rationale: Technical corrections. Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24679

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24680Response: EPA has revised §146.86(c)(3)(iii) and (iv) to reference the maximum proposed injection
p ressure and maximum proposed annular pressure, respectively. EPA has revised §146.86(c)(3)(v) to read "proposed injection rate (intermittent or cont inuous), and volume and/or mass of the carbon dioxide stream." EPA believes that refe rence to the continuous injection rate would be duplicative of the maximum rate. EPA believes that considering the maximum injection and annul ar pressure would be more protective.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)

Anadarko Petroleum Corporation (APC) Comments: (a) During the drilling and construction of a Class VI injection we ll, the owner or operator must run appropriate logs, surveys and tests to determine or verify the depth, thickness,
p orosity, permeability, and li thology of, and the salinity of any formation fluids in, all relevant geologic formations to assure conformance with the injection well construc tion requirements under §146.86, and to establish accurate baseline data against which futu re measurements may be compared. The owner or operator must submit to the Dire ctor a descriptive report prepared by a knowledgeable log analyst that includes an interpretation of the results of such logs and tests. At a minimum, such logs and tests must include: THE DIRECTOR MAY REQUIRE SUCH LOGS AND TESTS AS MAY BE NEEDED AFTER TAKING INTO ACCOUNT THE AVAILABILITY OF SIMILAR DATA IN TH E AREA OF THE DRILLING SITE, THE CONSTRUCTION PLAN, AND THE NEED FOR ADDITIONAL INFO RMATION THAT MAY ARISE FROM TIME TO TIME AS THE CONSTRUCTION OF THE WELL PROGRESSES AND THESE MAY INCLUDE THE FOLLOWING:

Rationale: In well defined areas, thes e evaluations are frequently unnecessary. The director should have discretion to select the appropriate requirements necessary to ensure sufficient baseline da ta and information are available. For example, in an area wher e a number of wells are bei ng drilled, the logging of surface hole yields little useful additional information. In particular, this change would allow the Director to reduc e the requirements when multiple wells are installed for a project.

Response: EPA disagrees that the require ments for logs, surveys, and tests are unnecessary. All logs, surveys, and tests listed at §146.87(a) are necessary to verify information about the injection and confining zones and ensure that the well is being drilled and cased as approved, and has mechanical integrity. This information is needed to demonstrate that the well can be operated and tested in a manner that protects USDWs from endange rment. While the tests do provide information on some of the same items, each test provides unique pieces of information that build on each other and allow for interpretations not possible with a single test.

EPA notes that the Director has the discretion at §146.87(a)(5) to a pprove alternative methods that Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24681p rovide equivalent or better information, and th e Director may accept information on cores of the injection and confining zones from nearby wells if the owner or ope rator can demonstrate that such cores are representative of conditi ons at the well in question and co re retrieval is not possible, as specified at §146.87(b). EPA believes that logs a nd tests must be performed on each well drilled regardless of existing information about the area to account for the co mplexity of CO2 injection well construction and the buoyancy of CO2. Existing lithologi c and geologic informati on may lack the details needed for site-specific well design and the geology needed to s upport protection of USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(2)(i)

Anadarko Petroleum Corporation (APC) Co mments: (i) Resistivity, spontaneous
p otential, and caliper logs before the casing is installed; and

Rationale: After a few wells are drilled in an area, these evaluations are frequently unnecessary and yi eld little new information. This is an example of where Director discretion may be appropriate.

Response: As described above, EPA disagrees that the re quirements for logs, surveys, and tests are excessive or duplicative. All logs , surveys, and tests listed at §146.87(a) are necessary to verify information about the injection and c onfining zones and ensure that the well is being drilled and cased as approved, and has mechanical integrity. EPA notes th at the Director has the discretion at §146.87(a)(5) to approve alternative methods that provi de equivalent or better information.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(2)(ii)

Anadarko Petroleum Corporation (APC) Comments: (ii) A Cement bond and variable density log, and a temperature log evaluation log(s) after the casing is set and cemented.

Rationale: Unusual to run these logs in a surface hole due to uniformity of shallow geology. This is an example of where Director discretion may be appropriate.

The proposed change provides more flexibi lity to select the appropriate log to demonstrate adequate cement bond.

Response: EPA clarifies at §146.87(a)(2)(ii) that owners or operators must perform a cement bond (i.e., cement evaluation) log after the casing is set and cemented. Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24682

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24683Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(3)(i)

Anadarko Petroleum Corporation (APC) Comments: Resistivity, spontaneous
p otential, porosity, caliper, ga mma ray, fracture finder logs and any other logs the Director requires BASED ON SITE SPECIFIC CONDITIONS AND RISK-BASED FACTORS for the given geology before the casing is installed; and

Rationale: It is acceptable to specify basic logging requirements, however, special logs should not be specified. Any other information from the area should be drawn on.

Response: EPA believes that a minimum suite of logs and tests is necessary at all Class VI wells. All logs, surveys, and tests listed at §146.87(a) are necessa ry to verify information about the injection and confining zones and ensure that the well is being drilled and cased as approved and has mechanical integrity.

EPA notes that owners or operators will describe in their permit applications how they will construct and test the well, and will also submit site-specific information about the subs urface geology. The Director will evaluate the proposed logging activities along with site-specific geologic in formation to identify geologic data of interest.

EPA adds that, should alternative methods be shown to provide equivalent or better information or if site-specific conditions and risk f actors dictate that other logs are necessary, the Director has the discretion at §146.87(a)(5) to require further logs a nd tests if necessary and to approve alternative methods that provide equivalent or better information.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)(3)(ii)

Anadarko Petroleum Corporation (APC) Comments: (ii) A Cement bond and variable density log, and a temperature log EVALUATION LOG(S) after the casing is set and cemented.

Rationale: The proposed change provides more flexibility to select the appropriate log to demonstrate adequate cement bond.

Response: EPA clarifies at 146.87(a)(3)(ii) that owners or operators must perform a cement bond (i.e., cement evaluation) log after the casing is set and cemented.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Lo gg in g and testin g requirements (40 Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24684

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24685

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24686CFR 146.87) Comment: Rule Provision: 146.87(a)(4)

Anadarko Petroleum Corporation (APC ) Comments: (4) A series of tests TEST(S) designed to demonstrate the internal a nd external mechanical integrity of injection wells, which may include: (i) A pressure test with liquid or gas; (ii) A tracer survey DIAGNOSTIC TOOLS such as oxygen-activation logging; (iii) A temperature or noise log; AND (iv) A casing inspection log. if required by the Director; and

Rationale: Technical and gr ammatical corrections

In (iv), "if required by the Director" is unnecessary.

Response: EPA disagrees that allowing the use of unspe cified "diagnostic tool s" would provide the same amount of information as the requirement to pe rform a tracer survey. The track record for tracer surveys in evaluating mechanical inte grity has been proven over time. The Agency clarifies that a tracer survey is one of the mechanical integrity tests that may be required by the Director or used by the owner or operator.

EPA agrees with the commenter about the wordi ng of the casing inspection log requirement at §146.87 (a)(4) and made the suggested change to improve clarity. In the final regulation, §146.87(a)(iv) does not include the phrase, “if required by the Director.”

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(b)

Anadarko Petroleum Corporation (APC) Comm ents: (b) The owner or operator must submit to the Director A REPORT DESCRIBING whole cores or sidewall cores REPRESENTATIVE of the injection zone a nd confining system a nd formation fluid samples from the injection zone(s). The Director may accept DATA from cores AND FLUID SAMPLES from nearby wells if the ow ner or operator can demonstrate that such DATA are representative of conditions in the wellbore.

Rationale: The information required should be sufficient to properly describe the injection and confining zones.

Response: EPA clarifies that it is not the Agency's in tent that physical core s be submitted to the Director. In the final GS rule, EPA has revised the first sentence of §146.87(b) to read as follows: "The owner or operator must take whole cores or sidewall cores of the in jection zone and confining system and formation fluid samples from the injection zone(s), and must submit to the Director a detailed report
p repared by a log analyst that includes: well log an alyses (including well logs), core analyses, and formation fluid sample information...." Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24687

Commenter Name: Crai g R. Walters Letter ID: 0200Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(c)

Anadarko Petroleum Corporation (APC) Co mments: (c) PRIOR TO INJECTION WELL OPERATION, the owner or operator must record the fluid FORMATION temperature, FORMATION FLUID pH and c onductivity, and reservoir pressure and the static fluid level of the injection zone(s).

Rationale: Technical correcti ons. Reservoir pressure and static fluid level are redundant parameters.

Response: EPA disagrees that "reservoir pressure" and "static fluid le vel" are redundant parameters. Although the static fluid level is equal to the bottom hole pressure, this may not always be identical to the reservoir pressure. Additionally, measuring the static fluid level provides additional assurance that the reading is accurate (or, provides the needed information in cases where a good reading is not obtained). In addition, a static flui d level measurement provides inform ation regarding the proximity to USDWs that need protection afforded to them.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(d)

Anadarko Petroleum Corporation (APC) Comm ents: (d) At a minimum, the owner or operator must determine or calculate th e following information concerning the injection and confining zone(s): (1) Fracture pressure; (2) Other physical and chemical character istics of the inj ection and confining zones; and (3) Physical and chemical characteristi cs of the formation fluids in the injection zone.

Rationale: With the excepti on of calculating fracture pressure, the requirements of this section appear redundant to othe r requirements of prior sections. The fracture pressure requirement has been added to section 146.87(e) below.

(2) and (3) are too vague.

Response: EPA believes that the requirement to provide information on the injection and confining zones in §146.87(d) is warranted, and that the rule provides flexibility to account for the variety of geologic conditions that may be encountered at GS sites.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24688

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24689

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24690Comment: Rule Provision: 146.87(e)

Anadarko Petroleum Corporation (APC) Comments: (e) (D) Upon completion but Prior to INJECTION WELL operation, th e owner or operato r must ESTIMATE FRACTURE PRESSURES OF THE INJECTION AND CONFINING ZONES AND conduct the following tests to verify hydrogeologic AND GEOMECHANICAL characteristics of the injection zone, E.G., INJECTIVITY TESTS, ESTIMATES BASED ON OPEN-HOLE LOGGING TOOLS (E.G. MECHANICAL PROPER TIES LOGS), AND OTHER APPROPRIATE METHODS. (1) A pump test; or (2) Injectivity tests.

Rationale: Allows the use of information such as leak off tests conducted during the drilling operation.

The results of a pump test (pumping flui d from the well) have no relevance for an injection well.

Deletion of the injectivity test would al low the use of non-destructive methods to calculate fracture pressure.

Response: EPA clarifies that the owner or operator has the optio n of using the pump tests or injectivity tests specified at §146.87(e) depending on which would provide the most valuable information based on site-specific conditions. Further, EPA disagrees that pump tests are irre levant to determining injection zone properties. Depending on the ch aracteristics or depth of knowledge of the confining and injection zone formations, pump tests may be necessary to prove that no hydrau lic connection exists between the injection zone and a USDW.

EPA disagrees that the wording at §146.87(d) would lead the owner or operator to employ destructive testing methods for determination of fracture pressure. The wording "d etermined or calculated" allows for calculations to be performed based on non-destructive methods.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(f)

Anadarko Petroleum Corporation (APC) Comm ents: (f) The owner or operator must
p rovide the Director with the opportunity to witness all logging and testing by this subpart. The owner or operator must s ubmit a schedule of such activities to the Director 30 days prior to conducting the first test UPON SPUDDING THE WELL and submit any changes to the schedule 30 days 48 HOURS prior to the
next scheduled test.

Rationale: The changes reflect the realit ies of flexible rig schedules and operations. In addition, they are fully consistent with current Class II requirements and practices, which deal with these issues on a daily basis.

Response: EPA disa g rees that the 30-da y notification requirement is unreasonable. Acknowled g in g the Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24691developing nature of CO2 GS, EPA believes that invol vement by the permitting authority in each project will provide much needed field data for assurance of USDW protection from endangerment and will help update and refine the permitting process. Adequate timing of notific ation will ensure the Director's ability to be involved.

Other EPA Comment Codes and Descriptions: 4110 2.4.1.1 Injection pressure limitations Comment: Rule Provision: 146.88(a)

Anadarko Petroleum Corporation (APC) Co mments: (a) Except during stimulation, the owner or operator must ensure that injection pressure does not exceed 90
p ercent of the fracture pressure of the injection zone so as to assure that the injection does not initiate new fractures or propagate existing fractures in the injection zone. In no case may injecti on pressure initiate fractures in the confining zone(s) or cause the movement of injection or formation fluids that endangers a USDW.

(A) THE OWNER OR OPERATOR MUST COMPLY WITH A MAXIMUM IN JECTION PRESSURE LIMIT APPROVED BY THE DIRECTOR AND SPECIFI ED IN THE PERMIT. IN APPROVING A MAXIMUM INJECTION PRESSURE LIMIT, THE DIRECTOR SHALL CONSIDER THE RESULTS OF WELL TESTS. THE DIRECTOR SHALL APPROVE LIMITS THAT, WITH A REASONABLE DEGREE OF CERTAINTY, WILL AVOID INITIATION OR PROPAGATION OF FRACTURES IN THE CONFINING ZONE OR CAUSE OTHERWISE NONTRANSMISSIVE FAULTS TR ANSECTING THE CONFINING ZONE TO BECOME TRANSMISSIVE. IN NO CASE MAY INJECT ION PRESSURE CAUSE MOVEMENT OF INJECTION OR FORMATION FLUIDS IN A MANNER PROH IBITED BY 40 CFR PART 144.12(A)

Rationale: Maintaining the integrity of the confining zone is the critical
p arameter.

Response: EPA notes that because determination of the in jection pressure limit is based on the fracture
p ressure of the injection zone, the limit is site-specific and not arbitrary. EPA em phasizes that injection
p ressure limits are important to prot ect against fracturing of the confining zone, and that the requirement at §146.88(a) that the pressure in the injection zone not exceed 90 percent of the fracture pressure
p rovides a margin of safety in the well operation and protects US DWs from endange rment. If the Director determines, based on a review of the information collected as pa rt of site characterization, that a lower injection pressure limitation is appropriate, the Di rector has the authority to set a lower limit in the operating permit than the limi t established in the rule.

EPA notes that during the site charac terization process, owners or opera tors must submit data about the geology of the site, as specified at §146.82(a), including data on known or suspected faults and fractures and geomechanical information on frac tures, stress, ductility, rock strength, and in situ fluid pressures within the confinin g zone. The Director will use these data to determin e appropriate limits on in j ection. Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24692In response to the concern about reopening of faults at lower pressures than 90 percent of fracture
p ressure, EPA believes that the requirement for th e owner or operator to submit data on known or suspected faults and fractures and information on the seismic history of the site will inform the determination of an appropriate pr essure limitation in the permit. Any sites with the potential for reopening or reactivation of faults or unacceptable seismic risk that could otherwise interfere with containment will not be permitted as GS sites.

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators in meeting the requirements of §146.82 a nd to assist directors in eval uating permit applications. The guidance will describe recommended approach es for characterizing the regional geology and hydrogeology of a proposed site and performing th e necessary geochemical, geomechanical, and geophysical analyses of the inject ion and confining zone. EPA is al so developing guidance for primacy agencies that will include recommended approaches for evaluating owner or operator-submitted data in setting permit conditions. The guidance wi ll be available on EPA's web site at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4100 2.4.1 Injection parameters Comment: Rule Provision: 146.88(b)

Anadarko Petroleum Corporation (APC) Comm ents: (b) Injection OF THE CO2 STREAM between the outermost casi ng protecting USDWs and the well bore is prohibited.

Rationale: Routine injection into zones other than the target interval(s) should be prohibited, however, wording of this requirement is not clear as to which interval is being addressed. An absolu te prohibition on injection into this annulus may also limit diagnostic options that could be useful.

Response: EPA retains the provision as propos ed, and clarifies that injection between the casing and the well bore is prohibited. This is consistent with requirements for other injection well classes.

Other EPA Comment Codes and Descriptions: 4100 2.4.1 Injection parameters Comment: Rule Provision: 146.88(c)

Anadarko Petroleum Corporation (APC) Comm ents: (c) The owner or operator mustfill the annulus between the tubing and the long string casing with a noncorrosive fluid approved by the Director. The owner or operator must maintain on the annulus a pressure that exce eds the operating injection pressure, unless the Director determines that such requirement might harm the integrity of the well. A POSITIVE PRESSURE ON THE ANNULUS.

Rationale: Industry experience with the Class II UIC program does not support this requirement.

Positive annular pressure that exceeds the operatin g in j ection pressure is not Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24693

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24694necessary because a leak from tubing to annulus does not have the same implications as in a Clas s I hazardous situation.

Response: EPA believes that maintaining an annulus pressure that is highe r than the injection pressure, as required at §146.88(c), will ensure that if there are leaks in the tubing, the annulus fluid will move into the tubing, rather than the inj ectate moving out of the tubing and potentially along the outside of the well. EPA believes this requirement is appropriate for Class VI well s given the potential high volumes and supercritical nature of the CO2 injectate, poten tial geomechanical stresses in the wellbore, and the
p otential for movement of the CO2 in the event of a mechanical integrity loss.

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: Rule Provision: 146.88(e)

Anadarko Petroleum Corporation (APC) Comm ents: (e) The owner or operator must install and use continuous r ecording devices to monitor: the injection pressure; the rate, volume, and temperature of the carbon dioxide stream and . THE OWNER OR OPERATOR MUST REGULARLY MONITOR the pressure on the annulus between the tubing and the long string casing and annulus fluid volume and . THE OWNER OR OPERATOR must install and use alarms and automatic down

- hole shut-off systems, designed to alert the operator and shutin the well when operating
p arameters such as injection rate, inj ection pressure, or other parameters approved by the Director diverge beyond ranges and/or gradients specified in the
p ermit;

Rationale: Over-pressure protection is be st achieved by ensuring compatibility of the casing/tubing material design st rength with the surface injection (compression) system. Down-hole shut-in devices are not appropriate for this application. These devises are installed in the tubing string and are typically near the surface of the well. They’re inte nded to seal the tubing in the event of catastrophic failure of the wellhead. These devises would provide little if any protection to USDWs. Is not practicable to install these devises deep within the well (e.g. shortly above the packer). Additionally these devises create a restriction on running othe r tools like logging tools in the well and therefore could limit an operators ability to do re quired monitoring and diagnostic work. Lastly, these devises require periodic testing and maintenance which could require either pulling the devise by wireline or by pulling the entire tubing string depending on the type of devise in stalled. Either of these activities would be disruptive and costly to the overall project operations.

A more appropriate approach would be installation of landing nipples at appropriate points in the tubing string which would allow use of wireline retrievable plugs when needed.

Response: As described above, EPA will not require au tomatic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells install automatic surface shut-off devices. The rule affords Director's discretion to mandate automatic Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24695down-hole shut-off devices in onshore situations that may warrant their use. The rule requires, at §146.88(e)(3), that owners or operators of offshore well s within State territorial waters install automatic down-hole shut-off systems. Please see the final rule and preamble fo r additional information on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: Rule Provision: 146.88(f)

Anadarko Petroleum Corporation (APC) Comments: (f) If aN down

- hole automatic shutdown is triggered or a loss of mechan ical integrity is discovered, the owner or operator must immediately investigate and identify as expeditiously as
p ossible the cause of the shutoff . If, upon such investigation, the well appears to be lacking mechanical inte grity, or if monitoring required under
p aragraph (e) of this section otherwise i ndicates that the well may be lacking mechanical integrity, the owner or operator must:

Rationale: Technical clarifi cation given changes above.

Response: As described above, EPA will not require au tomatic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells install automatic surface shut-off devices. The rule affords Director's discretion to mandate automatic down-hole shut-off devices in onshore situations that may warrant their use. The rule requires, at §146.88(e)(3), that owners or operators of offshore well s within State territorial waters install automatic down-hole shut-off systems. Please see the final rule and preamble fo r additional information on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4000 2.4 Proposed Injection Well Operating Requirements ( 40 CFR 146.88) Comment: Rule Provision: 146.88(f)(3)

Anadarko Petroleum Corporation (APC) Commen ts: (3) Notify the Director within 24 hours OF DISCOVERY;

N o rationale provided

Response: The final rule text at §146.88(f) now reads, "I f a shutdown (i.e., down-hole or at the surface) is triggered or a loss of mechanical integrity is discovered." Therefore the notice required at §146.88(f) (3) must be provided within 24 hours of an automati c shut-off device being triggered or a loss of mechanical integrity being discovered. EPA believes this provision is necessary to ensure timely response to potential USDW endangerment. Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24696

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24697

Commenter Name: Crai g R. Walters Letter ID: 0200Other EPA Comment Codes and Descriptions: 4520 2.5.1 Continuous internal mechanical integrity monitoring (seeking comment); 4720 2.7.2 Oper ational recordkeeping and reporting Comment: Rule Provision: 146.89(b)

Anadarko Petroleum Corporation (APC) Comm ents: (b) To evaluate the absence of significant leaks under paragraph (a)(1) of this section, owne rs or operators must, following an initial annulus pressure test, continuously monitor AND RECORD AT LEAST DAILY, ANNULUS PRESSURE AND VOLUMES OF PACKER FLUID INJECTED OR REMOVED FROM injection pressure, rate, injected volumes, and pressure on the annulus between THE tubing and long stem STRING casing and annulus fluid volume as specifi ed in §146.88 (e);

Rationale: Technical clarification.

Response: EPA agrees with the commenter regarding the importance of dem onstrating internal mechanical integrity (MI), but disagrees with the s uggested changes. Class VI injection wells will be equipped with dedicated computer-based continuous pressure monitoring devices in concert with the shut-off systems required for GS wells, which typically take readings several times per second (i.e., more frequently than daily) and record them el ectronically in a computer system. 40 CFR §146.91(a)(2) requires that monthly averages of the continuous annulus monitoring be reported on a semiannual basis.

40 CFR §146.91(a)(2) requires that monthly averages of the continuous annulus monitoring be reported on a semiannual basis. EPA agrees with the commente r that recording annulus fluid volume may not be appropriate. EPA believes that a nnulus fluid volume (146.88(e)) is a ne cessary component of monitoring well mechanical integrity, but beli eves that knowing the annulus fluid volume added is sufficient to meet the intent of the requirement. The final GS rule requires that owners or operators use continuous recording devices to monitor injection pressure, rate, and volume, as we ll as the pressure on the annulus between the tubing and the long stri ng casing. It also modifies the requirement in the proposed rule to continuously monitor annulus fluid volume; it now requires recording of annulus fluid volume added. See §§146.88(e), 146.89(b), and 146.90 (b). The final rule implements the suggested change from “longstem” to “long-string” casing.

Other EPA Comment Codes and Descriptions: 4540 2.5.2 Proposed external MIT requirements; 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: Rule Provision: 146.89(c)

Anadarko Petroleum Corporation (APC) Comm ents: (c) At least once per year, the owner or operator must confirm the absence of significant fluid movement under
p aragraph (a)(2) of this section USING A ME THOD ACCEPTABLE TO THE DIRECTOR (E.G. INCLUDING DIAGNOSTIC SURVEYS SUCH AS OXYGENAC TIVATION LOGGING OR TEMPERATURE OR N OISE LOGS).

(1) A tracer survey such as oxygen

- activation logging; (2) A temperature or noise log; or (3) A casing inspecti on log, if required by the Director. Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24698

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24699Rationale: Revised text supports a performance- b ased approach and allows the development and use of new technologies as they become available. Cement circulation to the surface is not necessary because having the open annulus above the top of cement allows regular monitoring of annular pressure which could indicate leakage.

N umber 3 was deleted because it requires the tubing to be pulled at significant cost and risk of uncontrolled releases.

Response: EPA believes that the MITs described in 146.89( c) of the rule (an approved tracer log or temperature or noise logs) are eff ective methods to demonstrate extern al MI, provide an important early warning of potential problems in th e injection well system, and repres ent standard techniques that have been used successfully by the dril ling industry and for the UIC Program for decades. The Agency notes that the regulations do provide the Director flexibility at §146.89(e) to approve the use of alternative MIT methods.

EPA agrees that the casing inspection log is not an appropriate test to detect fluid movement behind the casing, but clarifies that it is appropriate for determining the presen ce or absence of corrosion of the long-string casing, and is required if the Director determines that it is necessary based on site-specific information. EPA has revised the final GS rule to require that th e frequency of the casing inspection log must be specified in the approved te sting and monitoring plan. See §146.89(d).

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Rule Provision: 146.90 Anadarko Petroleum Corporation (APC) Comments: The owner or operator of a Class VI well must prepare, maintain, a nd comply with a testing and monitoring
p lan to verify that the geologic sequestration project is operating as permitted and is not endangering USDWs. The testing and monitoring plan must be submitted with the permit application, for Dire ctor approval, and must include a description of how the owner or operato r will meet the requirements of this section. Testing and monitoring associated with geologic sequestration projects must, at a minimum, include:

(A) BASED ON A SITE-SPECIFIC ASSE SSMENT OF THE POTENTIAL FOR FLUID MOVEMENT FROM THE INJECTION WELL OR INJECTION ZONE , AND ON THE POTENTIAL VALUE OF MONITORING WELLS TO DETECT SUCH MOVE MENT, THE OWNER OR OPERATOR OF A CLASS VI WELL MUST PREPARE, MAINTAIN, AND CO MPLY WITH A TESTING AN D MONITORING PLAN TO VERIFY THAT THE GEOLOGIC SEQUESTRATION PROJECT IS OPERATING AS PERMITTED AND IS NOT ENDANGERING USDWS. THE TESTING AND MO NITORING PLAN MU ST BE SUBMITTED WITH THE PERMIT APPLICATION, FOR DIRECTOR A PPROVAL AND INCLUDE A DESCRIPTION OF HOW THE OWNER OR OPERATOR WILL MEET THE RE QUIREMENTS OF TH IS SECTION; Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24700N o rationale provided

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA ha s made many revisions to the GS rule. See the final rule and
p reamble for further discussion on EPA's final approach.

EPA anticipates that the testing and monitoring pl an will address site-sp ecific geologic factors, modeling, and risk-assessment. EPA is developing guidance on how best to develop the various required
p roject plans, including the testing and monitoring plan. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: Rule Provision: 146.90(b)

Anadarko Petroleum Corporation (APC) Co mments: (b) The testing and monitoring
p lan must, at a minimum, include:

(a 1) Analysis of the carbon dioxide stream with sufficient frequency to yield data representative of its ch emical and physical characteristics; (b 2) Installation and use, except during well workovers as defined in § 146.86(d), of continuous recording MONITORING DEVICES (INCLUDING DIGITAL DEVICES CAPTURING PERIODIC DATA) to monito r injection pressure, rate and volume; AND TO RECORD AT LEAST DAILY the pressu re on the annulus between the tubing and the long string casing; and the annulus fluid volume; (3) A DEMONSTRATION OF EXTERNAL MECHANICAL INTEGRITY PURSUANT TO §146.89 (C) UNTIL THE WELL IS PLUGGED; (4) MONITORING OF THE PRESSURE BUIL DUP IN THE INJECTION ZONE ANNUALLY, INCLUDING AT A MINIMUM, A SHUTDOWN OF THE WE LL FOR A TIME SUFFICIENT TO CONDUCT A VALID OBSERVATION OF THE PRESSURE FALLOFF CURVE AT LEAST ONCE EVERY FIVE YEARS; AND (5) A QUALITY ASSURANCE PLAN FOR ALL TESTING AND MONITORING REQUIREMENTS.

(b) Installation and use, except during well workovers as defined in §146.88(d), of continuous monitoring de vices (including digital de vices capturing periodic data) to monitor injection pressure, rate and volume; and RECORD AT LEAST DAILY the pressure on the annu lus between the tubing and the long string casing;

Rationale: §146.86(d) does not exist; perhaps §146.88(d) is what was apparently intended.

There is concern regarding what cons titutes continuous monitoring. Industry

a g rees that re g ular monitorin g of the parameters identified b y EPA is Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24701appropriate. Our experience with CO2 EOR strongly shows that da ily monitoring of most of these parameters is adequate (e xceptions to this would be on a sitespecific basis). Recording should generally be done on a daily basis and reporting on a semi-annually basis. As a guiding principle, the frequency of monitoring should be determined by the le vel of risk posed by the injection operation.

Response: EPA believes that continuous pressure monito ring of GS wells, as required at §146.88(e), is important and appropriate because the potentially corrosive nature of CO2 streams in the presence of water makes it critical to immediately identify corro sion-related well mechanical integrity loss. Class VI injection wells must be equippe d with dedicated computer-based continuous pressure monitoring devices (in concert with the Dir ector-approved shut-off systems require d for GS wells), which typically take readings several times per second and record them electronically in a computer system..

EPA believes that a frequency of at least once every five years, as specified at §146.90(f), is an appropriate interval for pressure fall-off testing (p articularly given the suite of tests operators will
p erform on the well and the site). EPA clarifies that the Director may require more frequent pressure fall-off tests at a specific project, if necessary based on site-specific circumstances. Pressure fall-off tests may be conducted in conjunction with other well perfor mance tests (i.e., mechanical integrity testing) to ensure safe and effective operations . All monitoring data collected, in cluding information from pressure fall-off tests, will be incorporated in AoR reevaluations, at least every five years. EPA disagrees that the rule should provide specifics of the te sting at the degree suggested, however.

EPA clarifies that periodic MITs are not be required following plugging of the well.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: Rule Provision: 146.86(c)

Anadarko Petroleum Corporation (APC) Co mments: (C) WHERE APPROPRIATE, THE TESTING AND MONITORING PLAN SHALL ALSO INCLUDE:

(1) CONTINUOUS MONITORING FOR PRESSU RE CHANGES IN AN APPROPRIATELY POROUS AND PERMEABLE FORMATION OVERLYING THE CONFINING ZONE. WHEN A WELL IS INSTALLED TO ENABLE SUCH MONITORING, THE OWNER OR OPERATOR SHALL, ON A SPECIFIED FREQUENCY OR AT SPECIFIED TIMES, SAMPLE THE FORM ATION AND ANALYZE FOR CONSTITUENTS SPECIFIED IN THE PLAN;

(2) THE USE OF INDIRECT, GEOPHYSICAL TECHNIQUES TO DETER MINE THE POSITION OF THE CO2 STREAM FRONT, THE WATER QUALITY IN A DESIGNATED FORMATION, OR TO Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24702PROVIDE OTHER SITE SPECIFIC DATA;

(3) PERIODIC MONITORING OF WATER QUAL ITY IN AN APPROPRIATELY POROUS AND PERMEABLE FORMATION OVERLY ING THE INJECTION ZONE;

(4) PERIODIC MONITORING OF WATER QUALITY IN ONE OR MORE USDWS;

(5) CORROSION MONITORING OF THE WELL MATERIALS FOR LOSS OF MASS, THICKNESS, CRACKING, PITTING AND OTHER SIGNS OF CORROSION PERFORMED AND RECORDED AT LEAST QUARTERLY WHICH MAY BE MODIFIED TO BE LESS FREQUENT AS APPROVED BY THE DIRECTOR BASED ON CONSTRUCTION MATERIALS, OP ERATING CONDITIONS, AND MONITORING HISTORY TO ENSURE THAT THE WELL COMPONENTS MEET THE MINIMUM STANDARDS FOR MATERIAL STRENGTH AND PERFORMANCE SET FORTH IN §146.86(B) BY: (I) ANALYZING COUPONS OF THE WELL CONSTRUCTION MATERIALS PLACED IN CONTACT WITH THE CARBON DIOXIDE STREAM; OR (II) ROUTING THE CARBON DIOXIDE STREAM THROUGH A LOOP CONSTRUCTED WITH THE MATERIAL USED IN THE WELL AND INSPECT ING THE MATERIALS IN THE LOOP; OR (III) USING AN ALTERNATIVE METHOD, MATER IALS, OR TIME PERIOD APPROVED BY THE DIRECTOR;

(6) ANY ADDITIONAL TESTING AND MO NITORING APPROPRI ATE TO SUPPORT MODELING THE EXTENT OF THE CARBON DIOXIDE PLUME AN D THE POSITION OF THE PRESSURE FRONT; AND

(7) ANY ADDITIONAL TESTING AND MO NITORING NECESSARY TO DETERMINE WHETHER FLUID MOVEMENT IS OCCURRING INTO OR B ETWEEN USDWS THAT WOULD ENDANGER A USDW.

Rationale: Drilling monitoring wells should be carefully considered since each well introduces a potential pathway for m ovement. In addition the cost of adding multiple wells could create a barrier to CCS development, while providing limited information on actual m ovement of the CO2 stream.

APC questions the need for corrosion moni toring of most inj ected CO2 streams since they will typically be nearly pure and dry thus having no corrosive
p roperties. Industry experience with pr oduction, transportation, and injection of dry CO2 strongly illustrates the non-corrosive nature of this type of CO2
stream.

Response: EPA believes that quarterly corrosion monitoring of GS we lls is necessary. CO2 in thep resence of water (including water with NOx, SOx, and H2S impurities) can be corrosive to well materials and cements. Thus, although a CO2 stream may be dry, the pot ential for corrosion of well materials down-hole, where th e injectate can potentially mix with water in the target formation, must be considered.

Several laboratory studies and a limi ted number of field studies have i nvestigated and characterized the effects of carbonic acid on well materials. Laborat ory studies (e.g., Kutchko et al., 2007; Kutchko et al., 2008) consistently identify alterations (typically car bonation) of cement as the result of interactions between cement and CO2-saturated brine.

Currently, there are only a few analys es of cement from wells that have been in prolonged contact with CO2 in actual field (down-hole) c onditions. Evaluation of cement from a well at the Scurry Area Canyon Reef Operators Committee (SACROC) site show ed alteration, but did not show degradation that compromised the structural integrity of the ceme nt (Carey et al., 2007). In another study, cement samples were collected and analyzed from a CO 2 production well in a natural CO2 reservoir in Colorado exposed to a CO2-water down-hole envir onment for 30 years (Crow et al., 2008). The study found evidence of reaction between th e CO2-rich water and the cement.

Oil industry research also addresses the effects of corrosion of steel tubing and pipes. Lopez et al. (2003) noted that 60 percent of oilfield failures are related to the effects of carbonic acid from produced brines on carbon and low alloy steels.

Laboratory investigation of cement alteration/degradation is an ongoi ng research area. Few field-based studies have been completed to date. The laboratory and field studies currently available suggest that corrosion problems can be managed; however, there is not a large e nough body of research to rule out
p otential corrosion problems of st eel components of injection well s. The IPCC (2005) report on carbon dioxide capture and storage reviewed oil and gas i ndustry experience with gas injection wells, close industry analogues to CO2 injection wells. The report st ated that while the design of CO2 injection wells will be very similar to gas injection wells, most down-hole components of the CO2 injection wells will “need to be upgraded for higher pressure ratings and corrosion resistance.” Given the pressure and corrosion considerations, anticipated long lifespan of a GS well and the difficulties that would be associated with a corrosion-relate d well failure, EPA believes thatcorrosion monitoring in the downhole environment is justified. For these reasons, the fi nal rule requires quarterly corrosion monitoring at §146.90(c).

EPA maintains that plume tracking and pressure m onitoring are key component s of monitoring at GS sites. A rigorous plume tracking and pressure m onitoring scheme, such as one that meets the requirements at §146.90(g), is impera tive for ensuring that the CO2 plume is contained within the injection zone. Pressure monitoring in the injection zone is necessary to track the development and movement of the pressure front and CO2 plume. When combined w ith information on temperature,
p ressure data provide an indication of the phase (e.g., gas, supercritical) and distribution of the injected CO2. Monitoring can also identify needed remedi al actions, provide inputs for AoR reevaluation modeling, evaluate predictions of plume movement , and target additional geochemical and surface monitoring needs.

EPA also believes that the ground water geochemical monitoring outlined in §146.90(d) will maximize
p rotection of USDWs from endangerment at GS sites. Direct geochemical sampling is an important part of a monitoring program. See the final rule and prea mble for further discussion on EPA's final approach.

Commenter Name: Crai g R. Walters Letter ID: 0200Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: Rule Provision: 146.90(c)

Anadarko Petroleum Corporation (APC) Co mments: (c) Corrosion monitoring of the well materials for loss of mass, thickne ss, cracking, pitting and other signs of corrosion must be performed on a quarterly basis to ensure that the well components meet the minimum standards fo r material strength and performance set forth in § 146.86(b) by:

(1) Placing coupons of the well constr uction materials in contact with the carbon dioxide stream; or (2) Routing the carbon dioxi de stream through a l oop constructed with the material used in the well; or (3) Using an alternative method approved by the Director;

Rationale: See 146.90(5)(i-iii)

Response: EPA believes that corrosion monitoring is n ecessary for all Class VI wells to prevent endangerment of USDWs. CO2 in the presence of water (including water with NOx, SOx, and H2S impurities) can be corrosive to well materials and cements. Thus , although a CO2 stream may be dry, the potential for corrosion of well materials down-hole, where the in jectate can potentially mix with water in the target formation, must be considered.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4660 2.6.6 Geochemical monitoring Comment: Rule Provision: 146.90(d)

Anadarko Petroleum Corporation (APC) Co mments: (d) Periodic monitoring of the ground water quality and geochemical cha nges above the confining zone(s) that may be a result of carbon dioxide m ovement through the confining zone or additional identified zones:

(1) The location and number of monitoring wells must be based on specific information about the geol ogic sequestration project, including injection rate and volume, geology, the presence of artifi cial penetrations and other factors;

(2) The monitoring frequency and spatial distribution of monitoring wells must be based on baseline geochemical data that has been collected under § 146.82(a) (6) and any modeling results in the ar ea of review evaluation required by § 146.84(b);

Rationale: See 146.90(c)(1 thru 4 and 7)

Response: EPA did not make the su gg ested chan g es, but a g rees that monitorin g plans and methods need Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24703

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24704to be site-specific and based on baseline data and data collected throughout operations. EPA believes that the monitoring requirements for GS sites at §146.90 provide an appropriate level of flexibility in structuring a testing and monitoring plan that protects USDWs from endangerment.

The final regulation provides for flexibility in: 1) met hodologies used to collect these data, 2) the spatial resolution at which the data should be collected, a nd 3) how often the data should be collected. The number and placement of monitoring wells will be based on site-sp ecific information such as the calculated AoR, injection rate and volume, site geology, baseline data, and the presence of artificial
p enetrations within the AoR. In some instances, ther e may be a limited number of options for complying with EPA's minimum requirements. For example, monitoring for geochemical ch anges will require use of monitoring wells and collection of groundwater samples for chemical analysis. Many options currently exist for complying with other requirement s, such as tracking the position of the plume and
p ressure front within the injection zone.

Flexibility is also provided regarding how to monito r for the specific data required by the final rule. The testing and monitoring plan is developed by the owner or operator in consultati on with the Director and is designed to ensure that a detailed, Director -approved document describing how monitoring will be conducted during the lifetime of the project exists. EPA is de veloping guidance on testing and monitoring to assist owners or operators and Directors in evaluating requirements under §146.90, including proposed monitoring plans. The guidance describes availabl e technologies and recommended approaches for implementing a testing and monitoring plan, in cluding pre-operational geophysical logging and testing of injection we lls, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: Rule Provision: 146.90(e)

Anadarko Petroleum Corporation (APC) Comm ents: (e) A demonstration of external mechanical integrity pursuant to § 146.89(c) at least once per year throughout the duration of the geologi c sequestration project;

Rationale: See 146.90(b)(3)

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA ha s made many revisions to the GS rule. See the final rule and
p reamble for further discussion on EPA's final appr oach. EPA adds that the purpose of including all testing and monitoring requirements in §146.90 is to clarify and to specify the content of the required testing and monitoring plan.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: Rule Provision: 146.90(f) Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24705

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24706Anadarko Petroleum Corporation (A PC) Comments: (f) A pressure fall

- off test at least once every five years unless more frequent testing is required by the Director based on site specific information;

Rationale: See 146.90(b)(4)

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA ha s made many revisions to the GS rule. See the final rule and
p reamble for further discussion on EPA's final appr oach. EPA adds that the purpose of including all testing and monitoring requirements in §146.90 is to clarify and to specify the content of the required testing and monitoring plan.

Other EPA Comment Codes and Descriptions: 4650 2.6.5 CO2 plume and pressure front tracking (seeking comment) Comment: Rule Provision: 146.90(g)

Anadarko Petroleum Corporation (APC) Co mments: (g) Testing and monitoring to track the extent of the carbon dioxide plume and the position of the pressure front by either monitoring for pressure changes in the first formation overlying the confining zone or using indirect , geophysical techniques (e.g., seismic, electrical, gravity, or electromagnetic su rveys and/or down

- hole carbon dioxide detection tools);

Rationale: See 146.90(c)(1 thru 4 and 7)

Monitoring outside of the injection zone provides little information of value for tracking and monitoring the injected pl ume. Examples of how to test and monitor could be included in the Preamble but need not be included in the rule itself.

Response: EPA believes that direct pres sure measurements are appropriate and the final rule (at §146.90 (g)) requires owners or operators to perform monitoring to track the extent of the CO2 plume and
p ressure front. The owner or operator must use direct methods to monitor for pressure changes in the injection zone. Indirect methods (e.g., seismic, electrical, gravity, or electromagnetic surveys and/or down-hole CO2 detection tools) are also required unless the Director determines, based on site-specific geology, that such methods are not appropriate.

EPA believes that pressure monitoring in the inject ion zone is necessary to track the development and movement of the pressure front and CO2 plume. Monitoring can also id entify needed remedial actions,
p rovide inputs for AoR reevaluati on modeling, evaluate predictions of plume movement, and target additional geochemical and surface m onitoring needs. Knowledge of the location of the CO2 plume and the associated pressure front will assure the public that GS projects are proceed ing according to plan,
p rovide sufficient information to th e owner or operator and Director, or allow for appropriate actions to address any indication that USDWs may be endangered.

EPA acknowledges that, at ce rtain sites, there may be a need for more or different monitoring schemes (which ma y include monitorin g in the confinin g zone), and adds that it is important to balance the need Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24707for adequate monitoring that ensures USDW protec tion from endangerment agai nst too many artificial
p enetrations which could serve as conduits for fluid migration. Site-specific te sting and monitoring plans should describe the proposed monitoring regime, which must be approved by the Director. Flexibility is also provided regarding how to monito r for the specific data required by the final rule. The testing and monitoring plan is developed by the owner or operator in consultati on with the Director and is designed to ensure that a detailed, Director -approved document describing how monitoring will be conducted during the lifetime of the project exists.

EPA is developing guidance on testing and monitoring to assist owners or opera tors and Directors in evaluating requirements under §146.90, wh ich will include discussion of identifying the extent of the CO2 plume and pressure front. The guidance desc ribes available technologies and recommended approaches for implementing a testing and monitoring plan, in cluding pre-operational geophysical logging and testing of injection we lls, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/t ype/groundwater/uic/wells_sequestra tion.cfm. In addition, in January 2009, DOE published a best practices manual entitl ed "Monitoring, Verification, and Accounting of CO2 Stored in Deep Geologic Formations" (DOE/NETL-311/081508); this manual is included in the docket for the final GS rule.

Other EPA Comment Codes and Descriptions: 4670 2.6.7 Surface air monitoring and/or soil gas monitoring (seeking comment) Comment: Rule Provision: 146.90(h)

Anadarko Petroleum Corporation (A PC) Comments: (h) At the Director ’ s discretion, surface air monitori ng and/or soil gas monitoring to detect movement of carbon dioxide that could endanger a USDW.

(1) The testing and monitoring plan must be based on potent ial vulnerabilities within the area of review;

(2) The monitoring frequency and spatial distribution of surface air monitoring and/or soil gas monitoring must reflect baseline data and the monitoring plan must include how the proposed monitoring will yield useful information on the area of review delineation and/or compliance with standards under 40 CFR 144.12;

Rationale: In most situations soil a nd air monitoring does not provide an effective method of protecting USDWs.

Response: As described above, EPA acknowledges that air and soil gas monitori ng to ensure USDW
p rotection is not necessary at all GS sites and agrees that the decision to use surface monitoring and the selection of monitoring methods for the purpose of USDW protection will be site-specific.

In the final rule, at §146.90(h), the decision to requi re such monitoring as an additional measure to ensure USDW protection rests with th e Director as a means of identify ing leaks that may pose a risk to USDWs and informing emergency notif ication of a Class VI owner or operator and UIC Director in the event of a USDW endan g erment, pursuant to requirements at §146.91(c). Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24708The Agency agrees with the commenter that, if air and soil gas monitoring is performed, baseline soil CO2 levels need to be determined before monitori ng. This would be considered and described in the site-specific testing and monitoring plan.

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Rule Provision: 146.90(i)

Anadarko Petroleum Corporation (APC) Comments: (i) Any additional monitoring, as required by the Director, necessary to support, upgrade, and improve computational modeling of the area of review ev aluation required under § 146.84(b) and to determine compliance with standards under 40 CFR 144.12; and

Rationale: See 146.90(c)(6)

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA ha s made many revisions to the GS rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Rule Provision: 146.90(j)

Anadarko Petroleum Corporation (APC) Comments: (j) A quality assurance and surveillance plan for all testing and monitoring requirements.

Rationale: See 146.90(b)(5)

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA ha s made many revisions to the GS rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4720 2.7.2 Operational recor dkeeping and reporting Comment: Rule Provision: 146.91(a)

Anadarko Petroleum Corporation (APC) Comm ents: (a) Semi-annual OR LESS FREQUENT AT THE DISCRETION OF THE DI RECTOR reports containing:

(1) Any SIGNIFICANT change s to the physical, chemical and other relevant characteristics of the carbon dioxide stream from the proposed operating data; Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24709

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24710

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24711Rationale: Over the life of the project , the Director may decide that less reporting is acceptable

(1) Technical clarificati on. Significance can be deter mined by a statistical analysis of the data. Rules should recognize that there will be minor variations in many data se ts over time.

Response: EPA retained this provision as proposed. The final rule at §146.91(a)(3) requires reporting of all exceedances of operating parameters. EPA disagr ees with the suggestion to report only "significant" exceedances. Making a determination as to whether an exceedance is "significant" is not the purpose of the requirement. EPA believes that the ability of an operator to consistently meet operating requirements and avoid exceedances provides evidence of a well-man aged GS project that is in compliance with the Class VI permit. If multiple exceedances occur, the Director should be aware of such occurrences, and that information will aid in his/ her determination of whether these indicate problems at the site, and what is the appropriate course of action (e.g., a well workover, modification of operating parameters, or imposition of a penalty) to remediate such problem(s).

Other EPA Comment Codes and Descriptions: 4720 2.7.2 Operational recor dkeeping and reporting Comment: Rule Provision: 146.91(3) & (4)

Anadarko Petroleum Corporation (APC) Comments: (3) A description of any SIGNIFICANT event that exceeds operating parameters for annulus pressure or injection pressure as specified in the permit;

(4) A description of any SIGNIFICANT ev ent which triggers a shutdown device required pursuant to §146.88(e) and the response taken;

Rationale: EPA should consider some significance threshold on reporting these events to avoid reporting events that would be of limite d interest or
consequence.

Response: EPA retained this provision as proposed. The final rule at §146.91(a)(3) requires reporting of all exceedances of operating parameters. EPA disagr ees with the suggestion to report only "significant" exceedances. Making a determination as to whether an exceedance is "significant" is not the purpose of the requirement. EPA believes that the ability of an operator to consistently meet operating requirements and avoid exceedances provides evidence of a well-man aged GS project that is in compliance with the Class VI permit. If multiple exceedances occur, the Director should be aware of such occurrences, and that information will aid in his/ her determination of whether these indicate problems at the site, and what is the appropriate course of action (e.g., a well workover, modification of operating parameters, or imposition of a penalty) to remediate such problem(s).

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(a) Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24712

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24713Anadarko Petroleum Corporation (APC) Co mments: (a) Prior to the well plugging, the owner or operator must flush each Cl ass VI injection well with a buffer fluid, determine bottomhole reservoir pr essure, and perform a final EXTERNAL mechanical integrity test OF ANY R ELEVANT WELLBORE MATERIALS REMAINING.

Rationale: Many of the components that woul d be tested by an internal MIT are removed or tested during the plugging process.

Response: EPA agrees that only an external MIT is re quired, and has modified the GS rule at §146.92 (a) to require owners or operators to perform a final external mechanical integrity test prior to the well
p lugging.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(b)(2)

Anadarko Petroleum Corporation (APC) Comm ents: (2) Appropriate testing methods to ensure FINAL EXTERNAL mechanical integrity as specified in §146.89(C); ...

(5) The type and grade and quantity of ma terial to be used in plugging. The material must be SUITAB LE FOR USE with the carbon dioxide stream; and

Rationale: Many of the components that woul d be tested by an internal MIT are removed or tested during the plugging process.

Response: Regarding the suggested edit at 146.92(b)(2), EPA agrees that only an external MIT is required, and has modified the GS rule at §146.92(a) to require owners or opera tors to perform a final external mechanical integrity test prior to the well plugging.

Regarding the edit at 146.92(b)(5), EPA believes, cons idering the potentially corrosive nature of CO2 when it is in contact with water, that the requirement that the material must be compatible with the CO2 stream is appropriate. The final rule retains this requirement.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(d)

Anadarko Petroleum Corporation (APC) Co mments: (d) Plugging report. Within 60 days after plugging the owner or operato r must submit a plugging report to the Director. If the semi

- annual report is due less than 15 days after completion of plugging, then the report must be submitted within 60 days after plugging. The report must be certifie d as accurate by the owner or operator and by the
p erson who performed the plugging operatio n (if other than the owner or operator.) Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24714

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24715Rationale: The proposed changes are suggested to simplify and clarify a
p rovision that APC believes is needlessly complicated.

Response: EPA has revised the text at §146.92(d) to reduce c onfusion. The final rule text reads, "Within 60 days after plugging the owner or operator must submit a pluggi ng report to the Director."

Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities Comment: Rule Provision: 146.93(a)(1)

Anadarko Petroleum Corporation (APC) Co mments: (1) The owner or operator must submit the postinjection site care and site closure plan as a part of the permit application to be approved by the Director. SHALL CONTINUE TO CONDUCT MONITORING AS SPECIFIED IN THE DIRECTOR-APPROVED PO ST-INJECTION SITE CARE AND SITE CLOSURE PLAN, PURSUANT TO THE PERFORMANCE BASED CRITERIA DESCRIBED IN 146.93(3).

Rationale: Revisions here reflect changes to §146.93(b)(3)

Response: EPA disagrees with the suggested changes, a nd disagrees that the post-injection monitoring
p eriod should be stri ctly performance- b ased. The Agency agrees that ther e will be limited circumstances where it can be demonstrated in less than 50 year s that the plume and pressure front no longer pose a risk of endangerment to USDWs. For this reason, the GS rule offers owners or opera tors flexibility regarding the duration of the PISC timeframe by: (1) allowing the Direct or discretion to shorten or lengt hen the PISC timeframe during the
p ost-injection period based on site-specific data, pursuant to requi rements at §146.93(b); or (2) affording the Director discretion to allow a Class VI well ow ner or operator to demonstr ate, during the permitting
p rocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe for
p ost-injection site care will be necessary in most cases. The default 50 year post-injection site care timeframe represents a r easonable and protective monitoring peri od based on a review of research studies, industry reports, and exis ting environmental programs, and evaluation of public comments. EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts. The GS rule requires owners or operat ors to submit a post-injection site care and site closur e plan as part of the permit application, as specified in §146.82(a), in order to outline how these activities will be
p erformed and how non-endangerment of USDWs will be demonstrat ed throughout the post-injection site care period. Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24716Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.93(a)(2)

Anadarko Petroleum Corporatio n (APC) Comments: (2) The post

- injection site care and site closure plan must in clude the following information:

(i) The pressure differential betw een preinjection and predicted post

- injection
p ressures in the injection zone;

(ii) The predicted position of the carbon dioxide plume and a ssociated pressure front at site closure as demonstrated in the area of review evaluation required under § 146.84(b);

(iii) A description of post

- injection monitoring loca tion, methods, and proposed frequency; and

(iv) A proposed schedule for submitting post

- injection site care monitoring results to the Director.

Rationale: Revisions here reflect changes to §146.93(b)(3)

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5200 2.8.2 Post injecti on site care (seeking comment) (40 CFR 146.93) Comment: Rule Provision: 146.93(a)(4)

Anadarko Petroleum Corporation (APC) Commen ts: (4) AT ANY TIME DURING THE POSTINJECTION SITE CARE PHASE, The owner or operator may modify and resubmit the
p ost-injection site care and site closur e plan for the Director’s approval within 30 days of such change.

Rationale: Technical Clarification.

Response: EPA agrees that a post-injection site care monitoring plan is an important tool for GS and anticipates that, in some cases, the appropriate post-injection monitoring strategy may end up being different than initially pr ojected and there may be a need to amen d the post-injection site care and site closure plan. EPA is requiring that upon the cessation of injection, th e owner or operator submit an amended post-injection site care and site closure plan or demonstr ate to the Director that no changes to the original post-injection site care and site closure plan are necessary (146.93(a)(3)). EPA is not requiring formal periodic review and updates to the PI SC and site closure plan throughout the injection
p hase. EPA does not expect that changes to this plan would be implemented until injection operations cease. EPA envisions that owners or operators would take into acc ount similar considerations that g uide Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24717

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24718updates to other project plans, e.g., monitoring and operational data and results of AoR reevaluations. EPA adds that, if any mon itoring or other site data indicate a need for amendi ng the post-injection site care plan, the owner or operator is expected to am end the plan accordingly. EPA is issuing guidance with recommended approaches for development a nd updating of the GS project plans, including the
p ost-injection site care and site closure plan. The guidance will be availabl e on EPA's web site at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

EPA adds that, in the final rule, it has revised th e text at §146.93(a)(4) as foll ows: "At any time during the life of the geologic sequestration project, the owner or opera tor may modify and resubmit the postinjection site care and site closure plan for the Di rector’s approval within 30 days of such change."

Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities; 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: Rule Provision: 146.93(b)(1)

Anadarko Petroleum Corporation (APC) Comm ents: (1) The owner or operator shall continue to conduct monitoring as spec ified in the Director-approved postinjection site care and site closure plan, for at l east 50 years following the cessation of injection. At the Director ’ s discretion, the monitoring will continue until the geologic sequest ration project no longer poses an endangerment to USDWs. PURSUANT TO THE PERFORMANCE BASED CRITERIA DESCRIBED IN §146.93(B)(3).

Rationale: EPA should also reconsider it s proposed 50- year default period for
p ost-injection site care. EPA offers no rationale for this arbitrarily selected
p eriod of 50 years. Establishing a fixed and unusually long time period may create a significant barrier for opera tors considering entry into CCS operations. Criteria for determining the period for postinjection site care should be performance based and a function of the site specific characteristics of a project such as project size, geologi c factors, and relative risk of the
p roject. APC offers such criteria in our edits to §146.93(b)(3).

Response: EPA disagrees that a post-injection site care ti meframe of 50 years is excessive in most cases or arbitrary. EPA proposed a default post-injection site care timeframe of 50 years based on a review of research studies, industry reports, and existing envir onmental programs. This analysis was included in an EPA-prepared background document that is available in the fede ral docket, titled "Computational Modeling of Underground In jection of Carbon Dioxide for Dete rmination of Area-of-Review and Potential Risk to Underground Sources of Drinking Water." EPA assessed various default timeframes based on additional review of re search studies and evaluation of public comments. While numerous commenters suggested that EPA shorten the monito ring timeframe, none of the commenters provided sufficient data or other evidence to warrant a ch ange in the proposed time frame. While the 10- or 30- year timeframe suggested by some of these commenters may be within the timeframe suggested in some studies, EPA believes that the potential risks of e ndangering USDWs will likely not decline within these timeframes and available data, including data submitted by commenters, do not support a different default timeframe. However, EPA recognizes that alternative time frames may be appropriate under limited, specific circumstances. Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24719For this reason, the GS rule offers owners or opera tors flexibility regarding the duration of the PISC timeframe by: (1) allowing the Direct or discretion to shorten or lengt hen the PISC timeframe during the
p ost-injection period based on site-specific data, pursuant to requi rements at §146.93(b); or (2) affording the Director discretion to allow a Class VI well ow ner or operator to demonstr ate, during the permitting
p rocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts.

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe for
p ost-injection site care will be necessary in all buta limited number of cases. This default 50 year postinjection site care timeframe repres ents a reasonable and protective m onitoring period based on a review of research studies, industry repor ts, and existing envir onmental programs, and evaluation of public
comments.

EPA adds that the purpose of the GS rule is not to incentivize the use of GS. Rather, the purpose of the GS rule is to ensure that, where GS is deployed, it is conducted in a manner that protects USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities; 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: Rule Provision: 146.93(b)(2)

Anadarko Petroleum Corporation (APC) Comm ents: (2) If the owner or operator can request and demonstrate to the satisfact ion of the Director before 50 years, based on monitoring and other site

- specific data, that the geologic sequestration project no longer poses an e ndangerment to USDWs, the Director may approve an amendment to THAT the post-injection site care and site closure
p lan SHOULD BE REVISED to reduce the fr equency of monitoring. or may authorize site closure before the end of the 50

- year period.

Rationale: (See above)

Response: As described above, EPA disagrees that a post-in jection site care timeframe of 50 years is excessive in most cases or arbitrar y, and retains the default 50-year pos t-injection site care timeframe in the final rule.

Other EPA Comment Codes and Descriptions: 5280 2.8.2.4 USDW non-endangerment demonstrations Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24720

Commenter Name: Craig R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24721Comment: Rule Provision: 146.93(b)(3)

Anadarko Petroleum Corporation (APC) Comm ents: (3) Prior to authorization for site closure, the owner or operato r must submit to the Director a demonstration , DEMONSTRATE TO THE DIRECTOR, based on monitoring, and other site-specific data, AND MODELING THAT IS REASONABLY CONSISTENT WITH SITE PERFORMANCE that the carbon dioxide plume and pressure front have stabilized and that no additional monitoring is needed to assure that the geologic sequestration project does not pose an endangerment to USDWs.

THE OWNER OR OPERATOR MUST DEMO NSTRATE, BASED ON THE CURRENT UNDERSTANDING OF THE SITE, INCLUDING MONITORING DATA AND/OR MODELING, ALL OF THE FOLLOWING: (I) THE ESTIMATED MAGNITUDE AND EXTENT OF THE PROJECT FOOTPRINT (CO2 PLUME AND THE AREA OF ELEVATED PRESSURE); (II) THE ESTIMATED LOCATION OF THE DETECTABLE CO2 PLUME ; (III) THAT THERE IS NO SIGNIFIC ANT LEAKAGE OF EITHER CO2 OR DISPLACED FORMATION FLUIDS THAT IS ENDANGERING USDWS; (IV) THAT THE INJECTED OR DISPLACED FLUIDS ARE NOT EXPECTED TO MIGRATE IN THE FUTURE IN A MANNER THAT ENCOUNTERS A POTENTIAL LEAKAGE PATHWAY INTO A USDW; (V) THAT THE INJECTION WELLS AT THE SITE COMPLETED INTO OR THROUG H THE INJECTION ZONE OR CONFINING ZONE ARE PLUGGED AND ABANDONED IN ACCORDANCE WITH TH ESE REQUIREMENTS; AND (VI) ANY REMAINING PROJECT MONITORING WELLS AT THE SITE ARE BEING MANAGED BY A PERSON AND IN A MANNER ACCEPTABLE TO THE DIRECTOR.

Rationale: APC edits establish the performa nce based criteria for selecting the monitoring period.

EPA should recognize that under any given set of site specific conditions some of these criteria may not be fully sati sfied. EPA should retain the ability to waive individual monitoring criteria descri bed here to reflect that situation.

Response: EPA disagrees that the rule should specify the criteria for setting th e monitoring timeframe. Instead, EPA believes that such de terminations are site-specific and should be described in a projectspecific post-injection site care and site closure plan. EPA also be lieves that periodic reviews and updates, where necessary, to the plan are important to ensuring that the site continues to be managed effectively and to determine whether shortening the monitoring ti meframe is appropriate. The postinjection site care requirements in the final GS rule incorporate a combination of a fixed timeframe and a performance standard approach. The final GS rule offer owners or operators flexibility regarding the duration of the PISC timeframe by: (1) allowing the Director discretion to shorten or lengthen the PISC timeframe during the post-injecti on period based on site-specific da ta, pursuant to requirements at §146.93(b); or (2) affording the Direct or discretion to allow a Class VI well owner or operator to demonstrate, during the permitting pr ocess based on substantial data, that an alternative PISC timeframemay be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c). EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts. EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and monitoring wells, perform post-injection m onitoring, demonstrate the appropriateness of an alternative post-injection site care time fr ame, demonstrate non-endangerment, and perform site closure activities. The guidance will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment); 5260 2.8.2.3 Adjusting the post-injection timeframe (seeking comment) Comment: Rule Provision: 146.93(b)(4)

Anadarko Petroleum Corporation (APC) Co mments: (4) If such a demonstration cannot be made (i.e., if the carbon dioxide plume and pressure front have not stabilized) after the 50

- year period, the owner or ope rator must submit to the Director a plan to continue post

- injection site care.

Rationale: No longer necessary given changes above.

Response: As described above, EPA disagrees that a post-in jection site care timeframe of 50 years is excessive in most cases or arbitrar y, and retains the default 50-year pos t-injection site care timeframe in the final rule. .

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Rule Provision: 146.93(e)

Anadarko Petroleum Corporation (APC) Comments: (e) Once the Director has authorized site closure, the owner or ope rator must submit a site closure report within 90 days that must thereafter be retained at a location designated by the Director. AFTER COMPLETION OF ALL CLOSUR E OPERATIONS. The report must include:

(1) Documentation of appropriate inje ction and monitoring well plugging as specified in §146.92 and paragraph (c) of this section. The owner or operator must provide a cop y of a surve y plat which has been submitted to the local Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24722

Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24723zoning authority designated by the Director . The plat must indicate the location of the injection well(S) relative to perm anently surveyed benchmarks. The owner or operator must also submit a copy of the plat to the Regional Administrator of the appropriate EPA Regional Office;

Rationale: Once the site closure report is submitted to the Director, the operator cease to bear responsibility for any further record retention. At this
p oint, EPA becomes the steward of information for the project.

Response: EPA disagrees that the owner or operator should not be responsible for record retention such as site closure reports. EPA believes that the require ments that the owner or operator retain for ten years following site closure, records collected during the post-injecti on site care period at §146.93(f) and §146.93(h) are appropriate for the post-injection and site closure period to ensure that data are available to support non-endangerment de monstrations and to address any con cerns that may arise following site closure. This data will also suppor t EPA's review of project data as part of the adaptive rulemaking approach.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: Rule Provision: 146.94(b)

Anadarko Petroleum Corporation (APC) Co mments: (b) If the owner or operator obtains evidence that the injected car bon dioxide stream, DI SPLACED FORMATION FLUIDS OR and associated pressure front may cause an endangerment to ENDANGERS a USDW, the owner or operator must:

(1) Immediately cease injection IN A PRUD ENT MANNER CONSIDERING CIRCUMSTANCES.

(2) Take all steps reasonably necessary to identify and characterize THE ENDANGERMENT POSED;

(3) Notify the Director or the designat ed representative within 24 hours OF BECOMING AWARE OF TH E ENDANGERMENT; and

Rationale: Technical clarifications.

There is a slight change that immediat ely ceasing injection c ould have adverse impacts on other aspects of the operation.

Response: After consideration of comments, EPA has finalized the rule language in §146.94(b) as
p roposed. In the introductory section of §146.94(b), EPA clarifies that the pressure front, as defined in §146.81, is a zone where the pressure differential is suff icient to cause the moveme nt of injected fluids or formation fluids into a USDW. Therefore, displ aced formation fluids are im plicitly included in the requirements for §146.94. EPA also clarif ies that owners or operators must take action when the CO2 stream or pressure front may caus e endangerment. In order to preven t the endangerment of USDWs, as required under §1421 of the SDWA, EPA expects the ow ner or operator to act preemptively and not wait until endan g erment has occurred. This lan g ua g e is consistent with existin g UIC requirements for Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24724other well classes and EPA’ s authority under the SDWA.

EPA clarifies that the Agency expects that owners or operators should take care not to damage the well when ceasing injection under §146.94(b)(1). At §146.94(b)(2), EPA is maintaining the requirement to “characterize the release.” In order to prevent the endangerment of USDWs, as required under §1421 of the SDWA, EPA expects the owner or operator to act preemptively and not wait until endangerment has occurred. This language is consistent with existing UIC requirements for other well classes and EPA’s authority under the SDWA.

In response to commenters’ suggest ions regarding §146.94(b)(3), EPA clar ifies that the 24 hours begins when the owner or operator obtains evidence of possi ble endangerment. EPA beli eves the rule language is clear on this requirement.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: Rule Provision: 146.94(d)

Anadarko Petroleum Corporation (APC) Comm ents: (d) The owner or operator must notify the Director prior to conducting any well workover IN RESPONSE TO ANY CASE OF ENDANGERMENT.

Rationale: In critical situations, time spent obtaining approval could adversely affect the ability to conduc t operations or increase the level of endangerment.

Response: Since proposal, EPA has modified the final regulatory language at §146.94(d) to clarify what constitutes a workover to address a well failure (whi ch invokes remedial actions ) and what constitutes a maintenance-type workover. For maintenance-type workovers (i.e., those that are scheduled in advance), the owner or operator must notify a nd gain approval from the Director prior to beginning the workover. In the final GS regulation, EPA has moved this re quirement to the reporting requirements at §146.91(d) to clarify its intent.

Regarding concerns that notification could delay responses, EPA clarifies th at the GS rule (at §146.94 (b)) describes procedures owners or operators mu st take in emergency situations. Specifically, upon determining that there is a problem with the well that may endanger a USDW, the owner or operator must first cease injection, then take all steps reas onably necessary to identify and characterize any release, notify the Director, and implement the approved emergency and remedial response plan, which may include a well workover. EPA believes that ceasing injection (which the owner or operator would do immediately and before notifying the Director) is the immediate action ne cessary to prevent or mitigate endangerment of USDW s, as required under the SDWA.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: 1. EPA Proposed: §146.82 (f) Maps and st ratigraphic cross sections indicating the general vert ical and lateral limits of all USDWs, water wells and sprin g s within the area of review, their positions relative to Commenter Name: Crai g R. Walters Letter ID: 0200 Commenter Or g anization: Anadarko Petroleum Corporation Comment ID: 24725

Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbury Resources, Inc. (DRI) Comment ID: 24289the injection zone(s) and the direct ion of water movement, where known;

So long as the Applicant proposes to in ject CO2 below the lowermost USDW, as
p roposed under the rule, there is no ju stification to require maps and stratigraphic cross sections for the en tire extent of those USDWs above the lowermost USDW, although mapping and stra tigraphic cross sections in the immediate vicinity of the proposed injection locations (e.g. where the injection wells will be drilled) should still be re quired. Data regarding all USDWs in the AoR will likely be costly and/or diff icult to collect and, except as noted above, the usefulness of those data seems questionable.

Accordingly, Denbury suggests that subpara graph (f) should be modified as follows:

(f) Maps and stratigra phic cross sections indicating the general vertical and lateral limits of all THE LOWERMOST USDWs

, ALL USDWS IN THE IMMEDIATE VICINITY OF THE PROPOSED INJECTION WELL(S), water wells and springs within the area of review, th eir positions relative to the injection zone(s) a nd the direction of water movement, where known;

Response: EPA disagrees with the commenter that ther e is no justification to require maps and stratigraphic cross sections for the entire extent of those USDW s above the lowermost USDW. EPA believes that a thorough understanding of the hydroge ologic conditions of all USDWs in the AoR is necessary. EPA clarifies that §146.82(a)(5) requires, as part of the site characterization and permit application process, that operators submit maps and cross sections indicating the general vertical and lateral limits of all USDWs within the area of review. This information will resu lt in information on and a characterization of the number, location, and depth of USDWs. The Director has the authority to request additional hydrogeologic data or other data on USDWs as well.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: 2. EPA Proposed : §146.82(l) The results of the formation testing
p rogram as required in paragraph (j) of this section; (r) All available logging and testing program data on the well required by§ 146.87; (s) A demonstration of mechanical integrity pursuant to § 146.89;

The requirements of subparts (l), (r) and (s) of § 146.82 cannot be met until after the well is drille d. For example, subparagraph (l) references (j), formation testing. Clearly formation testing is a dr illing or post completion operation. Similarly, logging and mechanical integrity testing also are drilling or post well completion operations. Because this information will be collected
p ost application approval, it should not be required prior to the granting of the Class VI permit.

Denbury suggests that EPA modify § 146.82 to eliminate subparts (l), (r) and (s) because those data do not belong in and in fact may not be available as part of a permit application. Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24290Response: EPA agrees that not all of the information li sted at §146.82 of the proposed regulation will be available at the time the owner or operator develops their initial permit a pplication. In response to comments and based on an evaluation of the proposed requirements at §146.82, the Agency revised this subpart so that the final regulation specifies separate requirements for information to be submitted with the permit application and before well construc tion is approved (at §146.82(a)) and information to be submitted before operation of the we ll is authorized (at §146.82(c)).

EPA believes that this revision of §146.82 addresse s commenters' concerns regarding the timing of information to be submitted. In addition, section §146.82 in the final rule is similar to the permit application requirements for other in jection well classes, which could help avoid confusion about how to meet the permitting requirements fo r Class VI wells. The requirements at §146.82(c) for information to be submitted before operation of the well is authorized are very simila r to those for Class I wells, with modifications and additions that a ddress the unique challenges and types of data collected for GS wells.

Other EPA Comment Codes and Descriptions: 3330 2.2.1.3 Applicability /adequacy of computational models (seeking comment) Comment: B. §146.84 Area of review and corrective action.

EPA’s proposed rule allows each applicant to define the Area of Review ("AoR") associated with the sequestration proj ect. Denbury has no objection to this flexible approach as it allows the size and shape of the AoR to reflect the unique geology of each CO2 sequestration project. However, under §146.84 (a), to define the AoR, an applicant must us e a model capable of considering the
p hysical and chemical propert ies of all phases of th e injected carbon dioxide stream. Denbury is uncertain that there is a model that can satisfy this requirement. Accordingly, Denbury suggests th at the proposed rule be amended as follows:

§146.84 Area of review and corrective action. (a) The area of review is th e region surrounding the geologic sequestration project that may be im pacted by the injection activity. The area of review is based on computational modeling that, TO THE EXTENT PRACTICABLE AND TO THE EXTENT DETERMINED TO BE NECESSARY BY THE DIRECTOR, accounts for th e MATERIAL physical and ch emical properties of all CRITICAL phases of the injected carbon dioxide stream. Response: EPA disagrees that available mu ltiphase models ca nnot consider the physical and chemical
p roperties of all phases of the injected CO2 stream . Research, as discussed in the preamble to the
p roposed GS regulation and the associated background document "Computational Modeling of Underground Injection of Carbon Dioxide for Determination of Area-of-Review and Potential Risk to Underground Sources of Drinking Water" (cited in the proposed rule preamble as USEPA, 2008d), substantiates the modeling requirements in the GS regulation and indicates that technology has advanced to the point that a CO2 injecti on project can be adequately mode led to support both prediction and tracking the movement of the CO2 plume and pressu re front. EPA believes the Director should have discretion to evaluate each plan ba sed on current, state of the art modeling science because there are large numbers and types of available models and b ecause advances in the field of geologic modeling continue. Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24291Based on review of all public comments on the AoR definition at 146.84(a), the Ag ency has modified it to read as follows: The region surrounding the ge ologic sequestration project where USDWs may be endangered by the injection activity. The area of review is delineated using computational modeling that accounts for the physical and chemical properties of all phases of the injected CO2 stream and is based on available site characterization, monitoring, and operational data.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: Denbury suggests the following revision:

§146.86 (b) Casing and Cementing of Class VI Wells. (3) At least one long string casing, using a sufficient number of centralizers, must extend to the injection zone and must be cemented by circulating cement to the surface INJECTION ZONE AND CONFINING ZONE AND AN AUTHORIZED DISTANCE ABOV E THE CONFINING ZO NE, SUBMITTED BY THE PERMITTEE

AND APPROVED BY THE DIRECTOR in one or more stages. * * * (5) TO PROTECT USDWS, C cement and cement additives must be compatible with the carbon dioxide stre am and formation fluids and of sufficient quality and quantity to maintain integrity over the design OPERATING life of the WELL geologic sequestration
p roject MUST BE USED ACROSS THE INJECT ION ZONE AND CONFINING ZONE. The integrity and location of the cement shall be verified using technology capable of evaluating cement quality radially and identifying the location of channels to ensure that USDWs are not endangered.

Response: EPA disagrees that the casing, cement, or ot her materials should only be designed for the
p eriod of the injection process, ra ther than the life of the seques tration project. GS projects are anticipated to have long life-spans in comparison to other types of deep injection wells. Not only must Class VI wells be able to function sa fely and properly over the lifespan of the GS project, but they must b e constructed such that USDWs remain protecte d after well plugging. The requirements at §146.86 will ensure that the well can maintain integrity thr oughout the proposed life span of the project, including after the injection well is plugged and through the post-injection site care period and beyond. While the risk profile of a GS site will decrease following cessation of inje ction, EPA believes that Class VI wells must be designed to protect USDW s from endangerment for the life of the project. Furthermore, rigorous casing and cementing help ensure that the Class VI well will not serve as a conduit for movement of fluids associated wi th future injection operations.

Additionally, EPA is developing guida nce on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa .gov/type/groundwater/uic/wel ls_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Lo gg in g and testin g requirements (40 Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbury Resources, Inc. (DRI) Comment ID: 24295

Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbury Resources, Inc. (DRI) Comment ID: 24297CFR 146.87) Comment: 1. EPA Proposed § 146.87 (a)(2) Before and upon installation of the surface casing:... (ii) A cement bond and variable density log, and a temperature log after the casing is se t and cemented.

The requirements in §146.87(a)(2)(ii) to secure and submit specified logs before, upon and after surface casing installation is excessive. The proposed rule fails to provide a sufficient just ification for requiring a cement bond and variable density log before and upon inst allation of the long string casing, and requiring a temperature log after the cas ing is set and cemen ted. Temperature logs are seldom used in the dril ling industry to determine cement characteristics as they do not provide useful data regarding the bonding of cement. The rules should be modified to allow the permittee to select between the specified logs and any other logging tool approved by the Director as follows:

§146.87(a)(2)(ii) A cement bond and vari able density log OR OTHER APPROVED TOOL, and OR a temperature log after the casing is set and cemented. [see § 146.12(d)(2)(i) (B) Criteria and Standards applicable to Class I nonhazardous we lls: Construction Requirements.] * * * (5) Any alternative methods that provide equivalent or better information and that are required of and/or approved of by the Director. THE DIRECTOR MAY WAIVE AN Y LOG OR TEST SPECIFIED IN THIS SUBPARAGRAPH.

Response: Cement bond, variable density, and temper ature logs are required by §146.87(a)(2) upon installation of the surf ace casing. EPA disagrees that the su rface casing logging requirements are excessive. Evaluation of all logs, surv eys, and tests listed in the rule will provide detailed information on the parts of the well that will penetrate the lowermost USDW and pr ovide information on the quality of the cement seal with su rrounding formations in order to en sure protection of USDWs from endangerment.

As described above, EPA disagrees that any test s should be waived. While the tests do provide information on some of the same items, the tests provide unique pieces of information which enhance each other and allow for interpretations not possible wi th a single test. For example, a variable density log can detect microannuli, fractures, and formation effects. Temper ature logs can detect fluid or gas flow through channels that cannot be detected by either of the other tests.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: 2. EPA Proposed §146.87 (a)( (3) Before and upon installation of the long string casing: (i) Resistivity, spontaneous potential, porosity, caliper, gamma ray, fracture finder logs, and any other logs the Director requires for the given geol ogy before the casing is installed; and Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24298Once again, the proposed rule requires testi ng that would be of little benefit in protecting USDWs, but would impose significant costs on operators. For example, Denbury sees no ba sis to run a fracture find er log in every well. Fracture finder logs will only see mi nor fractures within the individual formations. The log does not provide information on whether these minor fractures can act as conduits between the injection zone and confining zone. To avoid unnecessary data collection and s ubmittal, the rules should allow the applicant to propose and justify a loggi ng suite based on the reservoir and geology associated with the particular CO2 project. The Director of course should be allowed to approve, or recommend revisions to the proposed suite. This would avoid mandating unneeded testing. De nbury suggests the following revised rule, incorporating this proposed change:

§146.87 (a)( (3) Before and upon installa tion of the long string casing: (i) Resistivity, spontaneous potenti al, porosity, caliper, gamma ray, fracture finder logs, and any other OR ANY SUITE OF LOGS SUBMITTED BY THE PERMITTEE AND APPROVED BY logs the Director BEFORE THE CASING IS INSTALLED requires for CONSIDERING the given geology before the casing is installed ; and

Response: EPA believes that a minimum suite of logs and tests is necessary at all Class VI wells. All logs, surveys, and tests listed at §146.87(a) are necessa ry to verify information about the injection and confining zones and ensure that the well is being drilled and cased as approved and has mechanical integrity.

EPA notes that owners or operators will describe in their permit applications how they will construct and test the well, and will also submit site-specific information about the subs urface geology. The Director will evaluate the proposed logging activities along with site-specific geologic in formation to identify geologic data of interest.

EPA adds that, should alternative methods be shown to provide equivalent or better information or if site-specific conditions and risk f actors dictate that other logs are necessary, the Director has the discretion at §146.87(a)(5) to require further logs a nd tests if necessary and to approve alternative methods that provide equivalent or better information.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: The proposed rule also requires unnecessa ry and duplicative logging with respect to the long-string casing.

3. EPA Proposed §146.87(a)( (3) Before and upon installation of the long string casing: (ii) A cement bond a nd variable density log, and a temperature log after the casing is set and cemented.

Denbury suggests that the logging options it recommends with respect to surface casing also apply for the long-string casing. Thus, the proposed rule should be revised as follows: Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24299§146.87(a)(3)(ii) A cement bond and vari able density log OR OTHER APPROVED TOOL, and OR a temperature log after the casing is set and cemented. [see § 146.12(d)(2)(ii)(C) Criteria and Standards applicable to Class I nonhazardous we lls: Construction Requirements.]

Response: EPA disagrees that the requirements for loggi ng of the long-string cas ing at §146.87(a)(3)(ii) are unnecessary. While the tests do provide information on some of th e same items, the tests provide unique pieces of information which enhance each othe r and allow for interpretations not possible with a single test. For example, a variable density log can detect microannuli, fractures, and formation effects. Temperature logs can detect fluid or gas flow through channels that ca nnot be detected by either of the other tests.

Determining the quality of the cementing of the l ong-string casing is essentia l to the protection of USDWs from endangerment. EPA adds that, should alternative methods be shown to provide equivalent or better information, the Director may allow such alternatives under §146.87(a)(5).

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: 4. EPA Proposed §146.87(b) The owner or operator must take and submit to the Director whole cores or sidewall cores of the injection zone and confining system and formation fluid samples from the injection zone(s). The Director may accept cores from n earby wells if the owner or operator can demonstrate that core retrieval is not possible and that such cores are representative of conditions at the well. The Director may require the owner or operator to core othe r formations in the borehole.

Denbury opposes the requirement to collect cores from more than one (1) well within a CO2 project. As a practical ma tter, the majority of the important
p hysical and geophysical properties of the injection reservoir, including the
p articular attributes of the confining fo rmations can and are required to be evaluated from logs and other scientific, reliable measures. A "whole core," as specified in §146.87(b) is only a very smal l sample of the attributes of a reservoir and a sidewa ll core, an even smaller sample. The former is very expensive to collect, and the latter ofte n not available. Neither is essential given the vast amount of data otherwis e required, and multiple samples, as
p roposed by the rule, are not reasonable. The unreasonableness of the whole core, sidewall core and extra core samp ling is evident upon consideration of the sheer volume of physical evidence that this provision alone may produce. For example, in Texas there are over 5000 existing Class II CO2 injection wells. If a small fraction of these wells are converted to Class VI CO2 injection wells following the completion of production activities, there will be a large universe of cuttings. Where will the regulatory agency store this magnitude of cuttings? This may become a particular problem given the total number of CO2 sequestration projects that may be proposed.

Denbury suggests the following: Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24300§146.87(b) AT THE SPECIFIC REQUEST OF THE DIRECTOR AND ONLY WHERE CORE RETRIEVAL IS POSSIBLE, TT he owner or operator must take and submit to the Director A whole cores or sidewall cores of the injection zone and confining system and formati on fluid samples from the injection zone(s). The Director may accept co res from nearby wells if the owner or operator can demonstrate that core retrieval is not possible and that such cores are representative of c onditions at the well. The Director may require the owner or operator to core other formations in the borehole.

Response: EPA clarifies that §146.87(b) allows information on cores from nearby wells to be submitted if the owner or operator can demons trate that core retrieval is not possible and that cores from nearby wells are representative of conditions at the Class VI well. EPA clarifie s that, at a minimum, reports on cores of injection zones, confining zones, and samples of formation fluids mu st be submitted. Section 146.87(b) gives the Director authority to require the ow ner or operator to core other formations in the borehole if necessary to provide sufficient geologic information to verify that the site is suitable for GS.

EPA clarifies that it is not the Agency's intent that physical cores be submitted to the Director. In the final GS rule, EPA has revised th e first sentence of §146.87(b) to r ead as follows: "The owner or operator must take whole cores or sidewall cores of the injection zone a nd confining system and formation fluid samples from the in jection zone(s), and must submit to the Director a detailed report
p repared by a log analyst that includes: well log an alyses (including well logs), core analyses, and formation fluid sample information...."

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: 6. EPA Proposed §146.87(f) The owner or operator must provide the Director with the opportunity to witn ess all logging and testing by this subpart. The owner or operator must subm it a schedule of such activities to the Director 30 days prior to c onducting the first test and submit any changes to the schedule 30 days prior to the next scheduled test.

The agency requires the submission of a proposed logging and testing schedule at least 30 days in advance of those pr oposed activities. Although a logging and testing schedule certainly can be designed 30 or more days in advance, the actual date that logging is performed is usually available only 24 to 48 hours in advance of actual logging operations. A mandatory 30 da y notice is simply not
p ractical for logging and test ing. Denbury asks that notice requirements in this subpart be adjusted to take into account the practical limitations experienced routinely in field operations. Suggested revised language is set forth below.

§146.87(f) The owner or operator must provide the Director with the opportunity to witness all logging and testing by this subpart. The owner or operator must submit a PROPOS ED schedule of such activities to the Director AT LEAST 30 days prio r to conducting the first test and submit NOTICE AT LEAST 24 HOURS IN A DVANCE OF THE CONDUCT OF ANY ACTUAL LOGGING AND TESTING. any changes to the schedule 30 days prior to the next scheduled test. Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24302Response: EPA disagrees that the 30-day notification requirement is unreasonable. Acknowledging the developing nature of CO2 GS, EPA believes that invol vement by the permitting authority in each project will provide much needed field data for assurance of USDW protection from endangerment and will help update and refine the permitting process. Adequate timing of notific ation will ensure the Director's ability to be involved.

Other EPA Comment Codes and Descriptions: 4100 2.4.1 Injection parameters Comment: E. § 146.88 Injection well operating requirements.

1. EPA Proposed §146.88(c) The owner or operator must fill the annulus between the tubing and the long stri ng casing with a non-corrosive fluid approved by the Director. The owner or operator must maintain on the annulus a pressure that exceeds the operating injection pressure, unless the Director determines that such re quirement might harm the integrity of the well.

EPA’s suggested Mechanical Integrity ("MI") rule to maintain pressure on the annulus exceeding the operating injection pr essure will, in most cases, result in an exceedance of the burst pressure of the casing. If the operator is required to maintain pressure on the annulus at a rate that is greater than the injection pressure (as indicated in EPA proposed §146.88(c)), monitoring the annulus pressure may not be an accurate indicator of mechanical integrity. The EPA appears to recognize this likelihood a nd thus allows the Director to waive the requirement. However, the rule should not require a quest ionable practice and then permit its waiver. Rather, the practice should only be required if the Director makes a determination that the conduct of the test will NOT cause a
p roblem. The suggested revision is encapsulated below:

(c) The owner or operator must fill the annulus between the tubing and the long string casing with a non-co rrosive fluid approved by the Director. IF THE DIRECTOR DETERMINES THAT SUCH REQU IREMENT WILL NOT HARM THE INTEGRITY OF THE WELL, Tt he owner or operator must maintain A POSITIVE PRESSURE on the annulus a pressure that exceeds the operating injection pressure. ., unle ss the Director determines that such requirement might harm the integrity of the well.

Response: EPA disagrees that maintaining annulus pressures that exceed the injection pressure would cause bursting of the casing. A properly designed well that takes into account the geologic and geomechanical properties of the site based on information collected under §146.82 and meets the construction requirements at §146.86 would be able to ma intain integrity if the annulus pressure were reasonably higher than injection pressure.

The purpose of continuous pressure monitoring (to dem onstrate internal MI) is to demonstrate that no
p ressure changes are occurring, because a drop in pr essure on the annulus provides an early indication that attention is needed to preven t a loss of MI or unacceptable flui d movement. EPA believes that any change in the pressure on the a nnulus between tubing and long stem casing, regardless of what the annulus pressure is relative to in j ection pressure, can indicate a leak. Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24303The GS rule, at §146.88(c), allows the Director to make exceptions if the Director determines that such a requirement might harm the integr ity of the well. The final regulat ion at §146.88(c) requires that the owner or operator must maintain on the annulus a pressure that exceeds the operating injection pressure, unless the Director determin es that such requirement might harm th e integrity of the well or endanger a USDW.

Other EPA Comment Codes and Descriptions: 4520 2.5.1 Continuous internal mechanical integrity monitoring (seeking comment) Comment: Furthermore, the requirement to continuou sly monitor the annulus fluid volume is impractical, because it does not provide a ny meaningful data regarding potential
p roblems with the operation of the well. Requiring the continuous monitoring of the amount of annulus fluid added during operations is more practical and will reveal potential leakage paths. Denbury recommends the following:

§146.88(e) The owner or operator must install and use continuous recording devices to monitor: The injection pressure; the rate, volume, and temperature of the carbon dioxide stream; and the pressure on the annulus between the tubing and the long string casing and THE VOLUME OF annulus fluid added to the annulus volume ; and the owner or operator must install and use alarms and automatic down

- hole shut-off systems, designed to alert the operator and shut- in off the well when operating parameters such as annulus pressure, injection rate or other parameters approved by the Director diverge beyond
p ermitted ranges and/or gradients specified in the permit. IF THE

Response: EPA believes that monitoring of annulus flui d volume is an important method for verifying that the well system is intact a nd is necessary for monitoring annulus pressure. While this requirement has, until now, been li mited to Class I hazardous waste injection wells, the high volumes and supercritical nature of the injectate, the potenti al geomechanical stresses in the wellbore, and the
p otential for movement of the buoyant CO2 in the ev ent of a MI loss make it an important safety consideration for GS projects. Continuous pressure monitoring allows imme diate identification of corrosion-related well integrity loss. EPA agrees with the commen ter that recording annulus fluid volume may not be appropriate. EPA believes that knowing annulus fluid volume as required at §146.88 (e) is a necessary component of m onitoring well mechanical integrity, but also believes that knowing the annulus fluid volume added is sufficient to meet the intent of the requirement. The final GS rule requires that owners or operators use c ontinuous recording devices to moni tor injection pressure, rate, and volume, as well as the pressure on the annulus be tween the tubing and the long string casing. It also modifies the requirement in the proposed rule to continuously monitor annulus fluid volume; it now requires recording of annulus fluid volum e added. See §§146.88(e); 146.89(b); and 146.90 (b).

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: OPERATION INVOLVES OFF-SHORE INJE CTION, THE OWNER OR OPERATOR MUST Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24305

Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24306INSTALL AND USE ALARMS AND AUTOMA TIC DOWN-HOLE SHUT-OFF SYSTEMS, DESIGNED TO ALERT THE OPERATOR AND SHUT-IN THE WELL IF THE WELLHEAD IS DAMAGED OR WHEN OPERATING PARAME TERS SUCH AS ANNULUS PRESSURE, INJECTION RATE OR OTHER PARAMETERS APPROVED BY THE DIRECTOR DIVERGE BEYOND PERMITTED RANGES AND/OR GRADIEN TS SPECIFIED IN THE PERMIT;

(f) If aN down

- hole automatic shutdown is triggered or a loss of mechanical integrity is discovered, the owner of operator must immediately investigate and identify as expeditiously as possible the cause of the shutoff.

Response: After evaluating the risks and benefits of down-hole shut-off systems and considering additional research, EPA will not require automa tic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells install automatic surface shut-off devices. The rule afford s Director's discretion to mandate automatic downhole shut-off devices in onshore situations that may warrant their use.

The GS rule, at §146.88(e)(3), requires the installation of down-hole shut-off devices for Class VI wells located in the offshore submerged lands within the jurisdiction of a State UIC program. The Agency believes that the unique construc tion and operational conditions for offshore Class VI wells, including isolation from shorelines and the need to construct wells through the water column and the subsurface, may delay response time in the event of well diffi culties. These conditions merit requiring automatic down-hole shut-off devices fo r offshore wells in the submerged lands of a State.

EPA believes that requiring the inst allation of automatic surface shut-off devices for onshore wells (and affording Director's discretion to require down-hole devices where necessary) and automatic down-hole shut-off devices for offshore wells in submerged lands within the juri sdiction of a State ensures that
p roper precautions are taken to prevent subsurface fl uid movement and ensure protection of USDWs, human health, and the environment.

Other EPA Comment Codes and Descriptions: 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: F. § 146.89 Mechanical integrity.

1. EPA Proposed §146.89(c) At least once per year, the owner or operator must use one of the following methods to determine the absence of significant fluid movement under paragraph (a)(2) of this section: (3) A casing inspection log, if required by the Director.

Among the test protocols prescribed by the proposed rule to confirm lack of significant fluid movement is a casing inspection log. Although this log is optional, it may be require d by the Director. Conducti ng a casing inspection log will require the tubing to be pulled from a well, and that in turn substantially increases the possibility of a well cont rol event (that is a loss of control over well operation). Accordingly, the te chnique should only be mandated when other testin g methodolo g ies are unavailable. Denbur y su gg ests the followin g Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24307edit:

§146.89(c) At least once per year, the owner or operator must use one of the following methods to determine the absence of significant fluid movement under paragraph (a)( 2) of this section: (3) A casing inspection log, if A TRAC ER SURVEY OR A TEMPERATURE OR N OISE LOG CANNOT BE OBTAINED AND A CASING INSPECTION LOG IS THUS required by the Director.

Response: EPA agrees that the casing inspection log is not an appropriate test to detect fluid movement b ehind the casing, but clarifies that it is appropriate for determining the presence or absence of corrosionof the long-string casing, and is required if the Director determines that it is necessary based on sitespecific information. EPA has revised the final GS rule to require that the frequency of the casing inspection log be specified in the approved testing and monitoring plan at §146.89(d).

Other EPA Comment Codes and Descriptions: 4620 2.6.2 Injectate monitoring Comment: G. § 146.90 Testing and monitoring requirements.

1. EPA Proposed §146.90(b) Installation and use, except during well workovers as defined in § 146.86(d), of continuous recording devices to monitor injection pressure, rate and volume; the pressure on the annulus between the tubing and the long stri ng casing; and the annulus fluid volume;

Consistent with our comment regarding proposed § 146.88(e) in Section 5 above, Denbury is unaware of a methodology to m onitor the actual volume of annular fluid in the annulus on a continuous basis, and thus seeks agen cy clarification on this portion of the proposed rule.

Response: EPA believes that knowing annul us fluid volume, as required at §146.88(e), is a necessary component of monitoring well mechanical integrity, but believes th at monitoring the annulus fluid volume added is sufficient to meet the intent of continuous monitoring of the pressure on the annulus. The final GS rule at §146.90 (b) requires that owners or operators use conti nuous recording devices to monitor injection pressure, rate, and volume; the pressure on the annulus between the tubing and the long string casing; and the a nnulus fluid volume added.

Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: 2. EPA Proposed §146.90(c) Corrosion moni toring of the well materials for loss of mass, thickness, cracking, pitting and other signs of corrosion must be performed on a quarterly basis to ensure that the well components meet the minimum standards for material strength and
p erformance set forth in § 146.86(b) by: (1) Placing coupons of the well constr uction materials in contact with the carbon dioxide stream; or (2) Routin g the carbon dioxide stream throu g h a loop constructed with Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24308

Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbury Resources, Inc. (DRI) Comment ID: 24309the material used in the well; or (3) Using an alternative method approved by the Director;

Denbury believes the requirements in EPA proposed §146.90(c) related to corrosion monitoring are inapplicable. In the vast majority of cases, the CO2 will be transported to the injection site through pipelines, will be dehydrated
p rior to transportation and therefore when injected it will be noncorrosive.[FN44] In those instances, th e test methods described in § 146.90(c) (1) and (c)(2) (except of course alternatives approved by the Director) will not
p rovide meaningful informat ion regarding the mechanical integrity of down-hole casing, tubing and other equipment because th e CO2 will simply not be corrosive at the surface. Consequently, to have a ny relevance such requirements should be reserved for situations where water saturated CO2 is being injected.

§146.90(c) Corrosion monitoring of the we ll materials for loss of mass, thickness, cracking, pitting and othe r signs of corrosion must be
p erformed on a quarterly basis to ensure that the well components THAT CONTACT WATER SATURA TED CARBON DIOXIDE STREAMS meet the minimum standards for material strength and performance set forth in § 146.86(b) by: (1) Placing coupons of the well c onstruction materials in contact with the carbon dioxide stream; or (2) Routing the car bon dioxide stream through a loop constructed with the ma terial used in the well; or (3) Using an alternative method approve d by the Director. THE REQUIREMENTS OF THIS SUBPART ARE WAIV ED WHEN THE CARBON DIOXIDE STREAM IS DEHYDRATED

TO MEET PIPELINE SPECIFICATIONS.

[44] For evidence on CO2 corrosiveness in the absence of free water see Don Duttlinger, "Enhanced Recovery Intertwines Naturally With CO2 Sequestration," Tech Connections Column, American Oil and Gas Reporter (January 2004), available at http://www.pttc.org/aogr_columns _archived/aogrcojan04.htm (From the
p rocessing/injection standpoint , CO2 is noncorrosive as long as it is dry. Proving that point, Kinder Morgan has hydro- tested the 32-year-old CRC Pipeline built in 1971 to transport CO2. Only one minor failure occurred. After testing, the line was rated for 2,025 psi maximum ope rating pressure, which established a 200 psi increase over most recent ratings); see also J. Layne, "Results of the Hydrotest of the 30-year old Canyon Reef Carriers CO2 Pipeline," 2003 CO2 Flooding Conference, University of Texas of the Permian Basin's Center for Energy and Economic Diversification, Midland,Texas (December 11-12, 2003).

Response: EPA disagrees that corrosion monitoring is unn ecessary or excessive. CO2 in the presence of water (including water with NOx, SOx, and H2S impurit ies) can be corrosive to well materials andcements. Thus, although a CO2 stream may be dry, the potential for corrosion of well materials downhole, where the injectate can potenti ally mix with water in the target formation, must be considered. EPA believes that the testing methods specified in the rule are appropriate and have been used successfully by Class I hazardous waste injection well owners or operators.

Several laboratory studies and a limi ted number of field studies have i nvestigated and characterized the effects of carbonic acid on well materials. Laborat ory studies (e.g., Kutchko et al., 2007; Kutchko et al.,2008) consistently identify alterations (typically car bonation) of cement as the result of interactions between cement and CO2-saturated brine.

Currently, there are only a few analys es of cement from wells that have been in prolonged contact with CO2 in actual field (down-hole) c onditions. Evaluation of cement from a well at the Scurry Area Canyon Reef Operators Committee (SACROC) site show ed alteration, but did not show degradation that compromised the structural integrity of the ceme nt (Carey et al., 2007). In another study, cement samples were collected and analyzed from a CO 2 production well in a natural CO2 reservoir in Colorado exposed to a CO2-water down-hole envir onment for 30 years (Crow et al., 2008). The study found evidence of reaction between th e CO2-rich water and the cement.

Oil industry research also addresses the effects of corrosion of steel tubing and pipes. Lopez et al. (2003) noted that 60 percent of oilfield failures are related to the effects of carbonic acid from produced brines on carbon and low alloy steels.

Laboratory investigation of cement alteration/degradation is an ongoi ng research area. Few field-based studies have been completed to date. The laboratory and field studies currently available suggest that corrosion problems can be managed; however, there is not a large e nough body of research to rule out
p otential corrosion problems of st eel components of injection well s. The IPCC (2005) report on carbon dioxide capture and storage reviewed oil and gas i ndustry experience with gas injection wells, close industry analogues to CO2 injection wells. The report st ated that while the design of CO2 injection wells will be very similar to gas injection wells, most down-hole components of the CO2 injection wells will “need to be upgraded for higher pressure ratings and corrosion resistance.” Given the pressure and corrosion considerations, anticipated long lifespan of a GS well and the difficulties that would be associated with a corrosion-relate d well failure, EPA believes thatcorrosion monitoring in the downhole environment is justified. For these reasons, the fi nal rule requires quarterly corrosion monitoring (at §146.90(c)). See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: H. § 146.92 Injection well plugging.

1. EPA Proposed §146.92 (b) Well Plugging Pl an. (5) The type and grade and quantity of material to be used in plugging. The material must be compatible with the carbon dioxide stream;

The proposed regulation requires the well bore to be flushed prior to plugging and thus it is unnecessary to use cement "compatible with the carbon dioxide stream." In the absence of water, CO2 is non-corrosive and compatible with conventional cements (see discussion under Comment #G). Accordingly, the rule should be revised as follows:

§146.92 (b) Well Plugging Plan. (5) The type and grade and quantity of material to be used in plugging. The material must be compatible with the carbon dioxide stream;

Response: EPA believes, considering the pote ntially corrosive nature of CO2 when it is in contact with water, that the requirement that the material must be compatible with the CO2 stream is appropriate. The Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24312final rule retains this requirement because CO2 and water will be present in the subsurface.

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment); 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: I. § 146.93 Post-injection site care and site closure.

The proposed rule establishes a 50 year default period for post-injection site care. There is, however, no factual or scie ntific basis for such an extensive
p eriod. Under EPA’s Resource Conservation a nd Recovery Act rules, which regulate the disposal of hazardous wastes, pos t closure care is limited to 30 years.[FN45] Defaulting to an excessively long period will increase costs and introduce greater regulatory uncertainty, which will discourage capital formation around CO2 sequestration. A more prudent regulatory approach is to set a minimum period for site care, ten years, with allowance for the Director to extend the period if facts and circumst ances warrant a longer post-injection site care period.

Additionally, the proposed rule’s 50 year default post injection site care
p eriod, is an illusory deadline, as it is not self-executing. Under the rules,
p ost injection site care must continue indefinitely until the Director authorizes closure. The closure approval pr ocess could take years, even decades, as the Director has no regulatory incent ive to act on any post injection site care report. Meanwhile, a permittee may be required to continue unnecessary and expensive monitoring and reporting indefinitely.

Denbury suggests that the post-injection site care rules be reconfigured to require a more limited mandatory post-in jection site care ti meframe, and to allow for closure at the end of that pe riod unless the Direct or affirmatively acts to extend the post-injection site ca re period. These changes are contained in the suggested text below:

§ 146.93 Post-injection site car e and site closure. (a) The owner or operator of a Class VI well must prepare, maintain, and comply with a plan for post-injection site care and site closure that meets the requirements of paragraph (a)(2) of this section and is acceptable to the Director. (1) The owner or operator must submit the post-injection site care and site closure plan as a part of the permit application to be approved by the Director. (2) The post-injection site care and site closure plan must include the following information: (i) The pressure differential between pre-injection and
p redicted post-injection pressu res in the injection zone; (ii) The predicted position of the carbon dioxide plume and associated pressure front at si te closure as demonstrated in the area of review evaluation required under § 146.84(b); (iii) A description of pos t-injection monitoring location, methods, and proposed frequenc y ; and Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbury Resources, Inc. (DRI) Comment ID: 24313(iv) A proposed schedule fo r submitting post-injection site care monito ring results to the Director. (3) Upon cessation of injection, owne rs or operators of Class VI wells must either submit an amended post-injection site care and site closure plan or demonstrate to the Director through monitoring data and modeling results that no amendmen t to the plan is needed.(4) The owner or operator may modify and resubmit the postinjection site care and site closure plan for the Director’s approval within 30 days of such change. (b) The owner or operator shall monito r the site following the cessation of injection to show the positi on of the carbon dioxide plume and
p ressure front and demonstrate that USDWs are not being endangered. (1) The owner or operator shall continue to conduct monitoring as specified in the Director-approved post-injection site care and site closure plan for at least 50 10 years following the cessation of injection. At the UPON A DETERMINATION BY THE Director ’ s THAT THE GEOLOGIC SEQUES TRATION PROJECT MAY POSE AN ENDANGERMENT TO USDWS discretion , THE DIRECTOR, AT HIS DISCRETION, MAY REQUIRE the monitoring will TO continue FOR A TIME PERIOD SPECIFIED BY THE DIRECTOR until the geologic se questration project no longer poses an endangerment to USDWs. (2) If the owner or operator can demonstrate to the satisfaction of the Director before 50 10 years, based on monitoring and other site-specific data, that the geol ogic sequestration project no longer
p oses an endangerment to USDWs, the Di rector may approve an amendment to the post injection site care and site closure plan to reduce the frequency of monitoring or may authorize site closure before the end of the 50 10 year period. (3) Prior to authorization for THE EXPIRATION OF THE 10 YEAR POST-INJECTION SITE CARE PERIOD, site closure , the owner or operator must submit to the Director a demonstration, based on monitoring and other site specific da ta, that the carbon dioxide plume and pressure front have stabilized and that no additional monitoring is needed to assure that the geologi c sequestration project does not pose an endangerment to USDWs. (4) IF WITHIN 180 DAYS AFTER THE SUBMITTAL OF THE DATA REQUIRED UNDER SUBPARAGRAPH (3) ABOVE TH E DIRECTOR DETERMINES THAT THE GEOLOGICAL SEQUESTRATION PROJECT MAY CONTINUE TO POSE AN ENDANGERMENT TO USDWS, HE SHALL SO NOTIFY THE OWNER OR OPERATOR OF HIS DETERMINATION AND THE BASIS THEREFORE, AND If such a demonstr ation cannot be made (i.e., if the carbon dioxide plume and pressure front have not stabilized) after the 50

- year period, the owner or operator must submit to the Director a
p lan to continue post-injection site care. (5) IF WITHIN 180 DAYS AFTER THE SUBMITTAL OF THE DATA REQUIRED UNDER SUBPARAGRAPH (3) ABOVE THE DIRE CTOR FAILS TO DETERMINE AND TO N OTIFY THE OWNER OR OPERATOR THAT THE GEOLOGICAL SEQUESTRATION PROJECT MAY CONTINUE TO POSE AN ENDANGERMENT TO USDWS, SITE CLOSURE SHALL BE DEEMED AUTHORIZED BY RULE (c) Notice of intent for site closure.The owner or operator must notify the Director at least 120 days before site closure. At this time, if a ny changes have been made to the original post-injection site care an d site closure pla n, the owner or operator must also provide the revised plan. At the discretion of the Director, a shorter notice period may be allowed. (d) After the Director ha s authorized site closur e OR SITE CLOSURE IS AUTHORIZED BY RULE, the owner or ope rator must plug all monitoring wells in a manner which will not allow move ment of injection or formation fluids that endangers a USDW. (e) Once the Director has authorized si te closure, OR SITE CLOSURE IS AUTHORIZED BY RULE, the owner or ope rator must submit a site closure report within 90 days that must thereafter be retained at a location designated by the Director. The report must include: (1) Documentation of appropriate injection and monitoring well
p lugging as specified in § 146.92 and para graph (c) of this section. The owner or operator must provide a copy of a survey plat which has been submitted to the local zoning authority designated by the Director. The
p lat must indicate the location of the injection well relative to
p ermanently surveyed benchmarks. The ow ner or operator must also submit a copy of the plat to the Regional Ad ministrator of the appropriate EPA Regional Office; (2) Documentation of appropriate notification and information to such State, local and tribal authorit ies as have authority over drilling activities to enable such State and local authorities to impose appropriate conditions on subsequent drilling activities that may
p enetrate the injection and confining zone(s); and (3) Records reflecting the nature, composition and volume of the carbon dioxide stream. (f) Each owner or operator of a Class VI injection well must record a notation on the deed to th e facility property or any other document that is normally examined during title search that will in perpetuity provide any potential purchaser of the prope rty the following information: (1) The fact that land has been used to sequester carbon dioxide; (2) The name of the State agency, local authority, and/or tribe with which the survey plat was filed, as well as the address of the Regional Environmental Protection Ag ency Office to which it was submitted; and (3) The volume of fluid injected, the injection zone or zones into which it was injected, and the period over which injection occurred. (g) The owner or operator must retain for three years following site closure, records collected during the post-injection site care period. The owner or operator must deliver th e records to the Director at the conclusion of the retenti on period, and the records must thereafter be retained at a location designated by the Director for that purpose.

[45] 40 C.F.R. § 264.117(a)(1)

Response: The post-injection site care requirements in the final GS rule, §146.93(b), incorporate a combination of a 50-year de fault post-injection site care timefram e, in conjunction with a performance standard, for Class VI wells. The GS rule offers owners or operators flexibilit y regarding the duration ofthe PISC timeframe by: (1) allowing the Director di scretion to shorten or le ngthen the PISC timeframe during the post-injection pe riod based on site-speci fic data, pursuant to re quirements at §146.93(b); or (2) affording the Director discreti on to allow a Class VI well owner or operator to demonstrate, during the permitting process based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangerment of USDW s pursuant to requirements at §146.93(c).

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe for
p ost-injection site care will be necessary in all buta limited number of cases. This default 50 year postinjection site care timeframe repres ents a reasonable and protective m onitoring period based on a review of research studies, industry repor ts, and existing envir onmental programs, and evaluation of public
comments.

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure monitoring and USDW impact s. EPA expects that the Director will consider the types of information the commenter describes in determining whether the plume and pressure front no longer pose a risk of endangerment to USDWs and post-injection site care monitoring may be discontinued.

EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and monitoring wells, perform post-injection m onitoring, demonstrate the appropriateness of an alternative post-injection site care time fr ame, demonstrate non-endangerment, and perform site closure activities. The guidance will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Comment: Page 43498. The Weyburn Field is in Saskatchewan, Canada, not Alberta.

Response: EPA acknowledges the comment and agrees.

Comment: Page 43500. Regarding the statem ent, "4-D seismic is a valuable tool for plume tracking" at Weyburn. "Is" is a strong word. Based on personal conversations with those who have worked on Weyburn, it is suggested that "may be" is more
accurate.

Response: EPA acknowledges the comment; this paragraph is not included in the preamble to the final rule. Commenter Name: Edward Steadman Letter ID: 0220 Commenter Or g anization: The Energy and Environmenta l Research Center at the University of North Dakota Comment ID: 21586

Commenter Name: Edward Steadman Letter ID: 0220 Commenter Or g anization: The Energy and Environmenta l Research Center at the University of North Dakota Comment ID: 21591Other EPA Comment Codes and Descriptions: 2060 1.5.3 Comments on grandfathering of existing wells (seeking comment); 3820 2.3.1 Well construction procedures Comment: 1. § 146.81 Applicability

The proposed rule provides that owners or operators of authorized Class I industrial, Class II, or Class V experiment al CO2 injection projects who seek to "convert" these wells to Class VI wells a nd apply for a Class VI permit may be exempted, at the Directo r’s discretion, from the pr oposed casing and cementing requirements applicable to Class VI wells.

EPA Proposed § 146.81(c) This subpart appl ies to owners and operators of
p ermit or rule- authori zed Class I industrial, Class II, or Class V experimental carbon dioxide injection projects who seek to apply for a Class VI geologic sequest ration permit for their well or wells. If the Director determines that USDWs will not be endangered, such wells are exempt, at the Director’s discreti on, from the casing and cementing requirements at §§ 146.86(b) and 146.87(a)(1) through (3).

It is helpful that EPA recognizes that entities may wish to convert other classes of wells (such as Class II well s used for CO2 enhanced oil recovery
p rojects) into Class VI wells and that flexibility is necessary for this conversion process. This flexibility should be maintained in the final rules but should be enhanced. In addition, the rules should be expanded to provide further detail on the conversion process. It is critical that owners and operators have clear and concise rules to rely on when seeking to grandfather their existing wells. This provision should be revised to limit the Director’s discretion and address all variances resulting in modifications to existing wells. For instance, while the rules waive the Clas s VI casing and cementing requirements for existing wells being converted to Cla ss VI wells, the rules do not address other construction or cons truction-related Class VI well requirements that create variances between Cl ass VI and Class I, II and V wells. Those requirements include:

1. Down hole automatic shut-off valve with wellhead hydraulics; 2. Annulus liquid level detector; 3. Wellhead corrosion monitoring equipment; and 4. Mechanical integrity testing.

Each of these requirement s applicable to Class VI wells would require retrofitting or modifications to existi ng wells and could make conversion of wells impracticable or excessively expensive. Rather than requiring existing wells to meet prescriptive rules that ma y not be necessary or applicable, the decision to grandfather an existing well should be based solely on the well’s
p assing a mechanical integrity test without physical well modification and meeting all other Class VI permit requirements that may be met without well modification. This change could be acco mplished by revising proposed § 146.81(c) as follows: Commenter Name: Darrick Eugene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture and Stora g e Association Comment ID: 23967(c) This subpart applies to owners and operators of permit or rule-authorized Class I industrial, Class II , or Class V experimental carbon dioxide injection
p rojects who seek to apply for a Class VI geologic sequestration permit for their well or wells. If the Director determines that USDWs will not be endangered THROUGH THE RESULTS OF MECHANIC AL INTEGRITY TESTING PURSUANT TO § 146.89 THAT THE WELL IS EFFECTIVE IN PREVENTING ENDANGERMENT OF USDWS, such wells are exempt, at the Director ’ s discretion , from the casing and cementing requirements at §§ 146.86( b) and 146.87(a)(1) through (3) ANY REQUIREMENT IMPOSING PHYSICAL WELL M ODIFICATIONS, SUBJEC T TO MEETING ALL OTHER CLASS VI WELL REQUIREMENTS.

Response: EPA expects that any decision to convert a well for long term storage of CO2 be made in the context of all available information about the site a nd history of injection. The final GS rule provides for the construction of these wells to be grandfathered per §146.81(c), provided the owner or operator can demonstrate to the Director that th e wells were engineered and constructed to meet the requirements at §146.86(a) and ensure protection of USDWs, in lieu of requirements at §146.86(b) and §146.87(a).

EPA clarifies that other Class VI requirements (i.e., beyond the constr uction requirements) will not be grandfathered. Following conversion of the project to Class VI, many of the uni que factors of GS sites (e.g., increased reservoir pressures associated with la rge volumes of stored CO2 and the corrosivity of CO2 in the presence of water) warrant the speci fic operational, MIT, monitoring, reporting, plugging,
p ost-injection site care, and site closure requirements in the final GS rule. Therefore, following rep ermitting, these projects must be subject to the requirements in the final GS rule, including requirements related to down-hole s hut-off devices, annulus fluid m onitoring, corrosion monitoring, and MITs. EPA adds that only requiring a MIT test for well s converting from Class I, II, or V would not be sufficient to ensure that the well was adequate to properly contain the buoyant and corrosive nature of the CO2 stream. EPA believes that down-hole shut-off systems and corrosion monitoring are also necessary to ensure the well maintains its inte grity. See the discussion of EPA's final regulatory approach in the preamble to the GS rule for additional detail on these requirements.

If, because of its construction, a current Class II we ll cannot be converted for GS in such a way that USDWs are protected from endange rment (i.e., by meeting the monito ring, MIT, and other requirements for Class VI wells), conversion will not be allowed. While conversion of su itable Class II wells for GS is desirable in many situations, EPA stresses that protection of USDWs from endangerment is the primary mission and mandate of the UIC program.

To clarify the point at which the primary purpose of CO2 injection transitions fr om ER (i.e., a Class II well) to long-term storage (i.e., Class VI), the final GS rule at §144.19 contains specific, risk-based factors to be considered by the Di rector in making this determinati on. Furthermore, EPA is developing guidance on transitioning from Class II to Class VI. The guidan ce will assist Directors and owner/operators in evaluating wher e a project may fit within a Cla ss II to Class VI transition. The guidance describes the methods availa ble for the Director to determine the risk posed to USDWs from a GS/ER project, and how the Director may determine if a project should be regulated by a Class II or Class VI UIC program. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Commenter Name: Darrick Eu g ene Letter ID: 0223Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82); 4710 2.7.1 Propos ed submissions required for permit applications (seeking comment) Comment: 2. § 146.82 Required Class VI permit information

This section of the proposed rule sets forth the information which the owner or operator must submit to the Director in order to obtain a Class VI well permit. All of the information specified must be part of the permit application. But some data are not necessary in light of other provisions of the current
p roposal, and some are not attainable prior to well drilling (applicants will not drill the well until it has been a pproved, otherwise they risk drilling an unusable well). Still other data can only be obtained after inj ection activities have been initiated. Post drilling and post injection data should not be required as part of the application process but instead should be considered confirmatory data that may be submitted after they are obtained. In general, the
p roposed rule should be modified to requi re submission of only those data which are needed for consideration of the init ial permit application, and only those data that may be reasonabl y obtained prior to commencement of installation and operation of the injection well.

EPA Proposed: §146.82 (f) Maps and stratigraphic cross sections indicating the general vert ical and lateral limits of all USDWs, water wells and springs within the area of review, their positions relative to the injection zone(s) and the directi on of water movement, where known;

So long as the Applicant proposes to in ject CO2 below the lowermost USDW, as required by the proposed rule, there is no justification to require maps and stratigraphic cross sections for the en tire extent of those USDWs above the lowermost USDW, although mapping and stra tigraphic cross sections in the immediate vicinity of the proposed injection locations (e.g. where the injection wells will be drilled) should still be re quired. Data regarding all USDWs in the AoR will likely be costly and/or diff icult to collect and, except as noted above, the usefulness of those data seems questionable.

Accordingly, TxCCSA suggests that subpara graph (f) should be modified as follows:

(f) Maps and stratigra phic cross sections indicating the general vertical and lateral limits of all THE LOWERMOST USDWs, ALL USDWS IN THE IMMEDIATE VICINITY OF THE PROPOS ED INJECTION WELL(S), water wells and springs within the area of review , their positions relative to the injection zone(s) and th e direction of water movement, where known;

EPA Proposed : §146.82(l) The results of the formation testing program as required in paragraph (j) of this section; (r) All available logging and testing program data on the well required by § 146.87; (s) A demonstration of mechanical integrity pursuant to § 146.89;

The requirements of subparts (l), (r) and (s) of § 146.82 cannot be met until after the well is drille d. For example, subparagraph (l) references (j), Commenter Or g anization: Texas Carbon Capture and Stora g e Association Comment ID: 23969formation testing. Clearly formation testing is a dr illing or post completion operation. Similarly, logging and mechanical integrity testing also are drilling or post well completion operations. Because this information will be collected
p ost application approval, it should not be required prior to the granting of the Class VI permit.

TxCCSA suggests that EPA modify § 146.82 to eliminate subparts (l), (r) and (s) because those data do not belong in and in fact may not be available as part of a permit application.

Response: EPA agrees that not all of the information li sted at §146.82 of the proposed regulation will be available at the time the owner or operator develops their initial permit a pplication. In response to comments and based on an evaluation of the proposed requirements at §146.82, the Agency revised this subpart so that the final regulation specifies separate requirements for information to be submitted with the permit application and before well construc tion is approved (at §146.82(a)) and information to be submitted before operation of the we ll is authorized (at §146.82(c)).

EPA believes that this revision of §146.82 addresse s commenters' concerns regarding the timing of information to be submitted. In addition, section §146.82 in the final rule is similar to the permit application requirements for other in jection well classes, which could help avoid confusion about how to meet the permitting requirements fo r Class VI wells. The requirements at §146.82(c) for information to be submitted before operation of the well is authorized are very simila r to those for Class I wells, with modifications and additions that a ddress the unique challenges and types of data collected for GS wells.

Additionally, EPA disagrees with the commenter that there is no justification to require maps and stratigraphic cross sections for the entire extent of those USDW s above the lowermost USDW. EPA believes a thorough understanding of the hydrogeologic conditions of all USDWs in the AoR is necessary. EPA clarifies that §146.82(a)(5) requires, as part of the site characterization and permit application process, that operators submit maps and cross sections indicating the general vertical and lateral limits of all USDWs within the area of review. This information will resu lt in information on and a characterization of the number, location and depth of USDWs. The Director has the authority to request additional hydrogeologic data or other data on USDWs as well.

Other EPA Comment Codes and Descriptions: 3330 2.2.1.3 Applicability /adequacy of computational models (seeking comment) Comment: 3. §146.84 Area of review and corrective action.

EPA’s proposed rule allows each applicant to define the Area of Review ("AoR") associated with the sequestration proj ect. TxCCSA has no objection to this flexible approach as it allows the size and shape of the AoR to reflect the unique geology of each CO2 sequestration project. However, under §146.84 (a), to define the AoR, an applicant must us e a model capable of considering the
p hysical and chemical propert ies of all phases of th e injected carbon dioxide stream. TxCCSA is uncertain that ther e is a model that can satisfy this requirement. Accordingly, TxCCSA suggests th at the proposed rule be amended as follows:

§146.84 Area of review and corrective action. (a) The area of review is Commenter Name: Darrick Eu g ene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture a nd Storage Association Comment ID: 23970the region surrounding the geologic se questration project that may be impacted by the injection activity. The area of review is based on computational modeli ng that, TO THE EXTENT PRACTI CABLE AND TO THE EXTENT DETERMINED TO BE NECESSARY BY THE DIRECTOR, accoun ts for the MATERIAL
p hysical and chemical properties of all CRITICAL phases of the injected carbon dioxide stream.

Response: EPA disagrees that available mu ltiphase models ca nnot consider the physical and chemical
p roperties of all phases of the injected CO2 stream . Research, as discussed in the preamble to the
p roposed GS regulation and the associated background document "Computational Modeling of Underground Injection of Carbon Dioxide for Determination of Area-of-Review and Potential Risk to Underground Sources of Drinking Water" (cited in the proposed rule preamble as USEPA, 2008d), substantiates the modeling requirements in the GS regulation and indicates that technology has advanced to the point that a CO2 injecti on project can be adequately mode led to support both prediction and tracking the movement of the CO2 plume and pressu re front. EPA believes the Director should have discretion to evaluate each plan ba sed on current, state of the art modeling science because there are large numbers and types of available models and b ecause advances in the field of geologic modeling continue.

Based on review of all public comments on the AoR definition at 146.84(a), the Ag ency has modified it to read as follows: The region surrounding the ge ologic sequestration project where USDWs may be endangered by the injection activity. The area of review is delineated using computational modeling that accounts for the physical and chemical properties of all phases of the injected CO2 stream and is based on available site characterization, monitoring, and operational data.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: TxCCSA suggests the following revision:

§146.86 (b) Casing and Cementing of Class VI Wells. (3) At least one long string casing, using a sufficient number of centralizers, must extend to the injection zone and must be cemented by circulating cement across the surface INJECTION ZONE AND CONFINING ZONE AND AN AUTHORIZED DISTANCE ABOV E THE CONFINING ZO NE, SUBMITTED BY THE PERMITTEE

AND APPROVED BY THE DIRECTOR in one or more stages. * * * (5) TO PROTECT USDWS, C Cement and cement additives must be compatible with the carbon dioxide stre am and formation fluids and of sufficient quality and quantity to maintain integrity over the design OPERATING life of the WELL geologic sequestration project MUST BE USED THROUGH THE INJECTIO N ZONE AND CONFINING ZONE. The integrity and location of the cement shall be verified using technology capable of evaluating cement quality radially and identifying the location of channels to ensure that USDWs are not endangered. Commenter Name: Darrick Eu g ene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture a nd Storage Association Comment ID: 23973Response: EPA disagrees that the casing, cement or other materials should only be designed for the
p eriod of the injection process, ra ther than the life of the seques tration project. GS projects are anticipated to have long life spans in comparison to other types of deep injection wells. Not only must Class VI wells be able to function sa fely and properly over the lifespan of the GS project, but they must b e constructed such that USDWs remain protecte d after well plugging. The requirements at §146.86 will ensure that the well can maintain integrity thr oughout the proposed life span of the project, including after the injection well is plugged and through post-injection site care period and beyond. While the risk
p rofile of a GS site will decrease following cessation of injection, EPA believes that Class VI wells must be designed to protect USDWs from endangerment for the life of the project. Furthermore, rigorous casing and cementing help ensure th at the Class VI well will not se rve as a conduit for movement of fluids associated with future injection operations . EPA believes that the requirements for long-string casing are appropriate and offer appropriate flexibility: §146.86(b)(3) requires that the long-string casing extend to the injection zone and be cemented by circulating cement to the surface in one or more stages. It does not, however, specify how cementing would be accomplished, and gives fl exibility to the owner or operator to propose altern ate methods to provide a sufficient am ount of cement to meet the standard that USDWs are protected from endangerment, subject to the approva l of the Director.

Additionally, EPA is developing guida nce on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa .gov/type/groundwater/uic/wel ls_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: cement. The rules should be modified to allow the permittee to select between the specified logs and any other logging tool approved by the Director as follows:

§146.87(a)(2)(ii) A cement bond and vari able density log OR OTHER APPROVED TOOL, and OR a temperature log after the casing is set and cemented. [see § 146.12(d)(2)(i)(B) CRITER IA AND STANDARDS APPLICABLE TO CLASS I NONHAZARDOUS WELLS: CONSTRUCTION REQUIREMENTS.] * * * (5) Any alternative methods that provide equivalent or better information and that are required of and/or approved of by the Director. THE DIRECTOR MAY WAIVE AN Y LOG OR TEST SPECIFIED IN THIS SUBPARAGRAPH.

Response: Cement bond, variable density, and temper ature logs are required by §146.87(a)(2) upon installation of the surf ace casing. EPA disagrees that the su rface casing logging requirements are excessive. Evaluation of all logs, surv eys, and tests listed in the rule will provide detailed information on the parts of the well that will penetrate the lowermost USDW and pr ovide information on the quality of the cement seal with su rrounding formations in order to en sure protection of USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Lo gg in g and testin g requirements (40 Commenter Name: Darrick Eu g ene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture and Stora g e Association Comment ID: 23975

Commenter Name: Darrick Eu g ene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture a nd Storage Association Comment ID: 23977CFR 146.87) Comment: The proposed rule also requires unnecessa ry and duplicative logging with respect to the long-string casing.

EPA Proposed §146.87(a)( (3) Before a nd upon installation of the long string casing: (ii) A cement bond a nd variable density log, and a temperature log after the casing is set and cemented.

TxCCSA suggests that the logging options it recommends with respect to surface casing also apply for the long-string casi ng. Thus, the proposed rule should be revised as follows:

§146.87(a)(3)(ii) A cement bond and vari able density log OR OTHER APPROVED TOOL, and OR a temperature log after the casing is set and cemented. [see § 146.12(d)(2)(ii)(C) CR ITERIA AND STANDARDS A PPLICABLE TO CLASS I N ONHAZARDOUS WELLS: CONSTRUCTION REQUIREMENTS.]

Response: EPA disagrees that the requirements for loggi ng of the long-string cas ing at §146.87(a)(3)(ii) are unnecessary. While the tests do provide information on some of th e same items, the tests provide unique pieces of information which enhance each othe r and allow for interpretations not possible with a single test. For example, a variable density log can detect microannuli, fractures, and formation effects. Temperature logs can detect fluid or gas flow through channels that ca nnot be detected by either of the other tests.

Determining the quality of the cementing of the l ong-string casing is essentia l to the protection of USDWs from endangerment. EPA adds that should alte rnative methods be shown to provide equivalent or better information, the Director may allow such alternatives under §146.87(a)(5).

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: TxCCSA suggests the following:

§146.87(b) AT THE SPECIFIC REQUEST OF TH E DIRECTOR AND ON LY WHERE CORE RETRIEVAL IS POSSIBLE, TT he owner or operator must take and submit to the Director A whole cores or sidewall cores of the injection zone and confining system and formation fluid samples from the injection zone(s). The Director may accept co res from nearby wells if the owner or operator can demonstrate that core retrieval is not possible and that such cores are representative of c onditions at the well. The Director may require the owner or operator to core other formations in the borehole.

Response: As described above, EPA clarif ies that §146.87(b) allows info rmation on cores from nearby wells to be submitted if the owner or operator can demonstrate that core retrieval is not possible and that cores from nearby wells are represen tative of conditions at the Class VI well. EPA clarifies that, at a minimum, reports on cores of injecti on zones, confining zones, and samp les of formation fluids must be submitted. Section 146.87(b) gives the Director authority to require the owner or operator to core other formations in the borehole if necessar y to provide sufficient g eolo g ic information to verif y that the site Commenter Name: Darrick Eugene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture and Stora g e Association Comment ID: 23980is suitable for GS.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: EPA Proposed §146.87(f) The owner or operator must provide the Director with the opportunity to witness all logging and testing by this subpart. The owner or operator must submit a schedule of such activities to the Director 30 days prior to conducting the first test and submit any changes to the schedule 30 days prior to the next scheduled test.

The agency requires the submission of a proposed logging and testing schedule at least 30 days in advance of those pr oposed activities. Although a logging and testing schedule certainly can be designed 30 or more days in advance, the actual date that logging is performed is usually available only 24 to 48 hours in advance of actual logging operations. A mandatory 30 da y notice is simply not
p ractical for logging and testing.

TxCCSA asks that notice requirements in this subpart be adjusted to take into account the practical limitations experi enced routinely in field operations. Suggested revised language is set forth below.

§146.87(f) The owner or operator must provide the Director with the opportunity to witness all logging and testing by this subpart. The owner or operator must submit a PROPOS ED schedule of such activities to the Director AT LEAST 30 days prio r to conducting the first test and submit NOTICE AT LEAST 24 HOURS IN A DVANCE OF THE CONDUCT OF ANY ACTUAL LOGGING AND TESTING. any changes to the schedule 30 days prior to the next scheduled test.

Response: EPA disagrees that the 30-day notificati on requirement is unreasonable. The 30-day notification mirrors the current requirement for logging and testing of new Class I wells, as described in §146.66. Acknowledging the developing nature of CO2 GS, EPA believes that involvement by the
p ermitting authority in each projec t will provide much needed field data for assurance of USDW
p rotection from endangerment and will help update a nd refine the permitting pr ocess. Adequate timing of notification will ensure the Director's ability to be involved.

Other EPA Comment Codes and Descriptions: 4100 2.4.1 Injection parameters Comment: problem. The suggested revision is encapsulated below:

(c) The owner or operator must fill the annulus between the tubing and the long string casing with a non-co rrosive fluid approved by the Director. IF THE DIRECTOR DETERMINES THAT SUCH REQU IREMENT WILL NOT HARM THE INTEGRITY OF THE WELL, Tt he owner or operator must maintain A POSITIVE PRESSURE on the annulus a pressure that exceeds the operatin g in j ection pressure. ., unless the Director determines that Commenter Name: Darrick Eu g ene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture a nd Storage Association Comment ID: 23982

Commenter Name: Darrick Eu g ene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture a nd Storage Association Comment ID: 23984such requirement might harm the integrity of the well.

Response: As described above, EPA disagrees that main taining annulus pressures that exceed the injection pressure would cause bursting of the casing. Therefore, EPA disagrees with the suggested revision.

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: EPA Proposed §146.88(e) The owner or operator must install and use continuous recording devices to moni tor: The injection pressure; the rate, volume, and temperature of th e carbon dioxide stream; and the
p ressure on the annulus between the tubing and the long string casing and annulus fluid volume; and must in stall and use alarms and automatic down-hole shut-off systems, designed to alert the operator and shut-in the well when operating parameters such as annulus pressure, injection rate or other parameters approved by the Director diverge beyond
p ermitted ranges and/or gradients specified in the permit;

The installation and use of automatic do wn-hole shut-off systems creates a
p otential avenue for leakage and is unnecessary on lan d -based onshore systems. Down-hole shut-off systems, more commonly used in off-shore operations, serve to shut in the well and prevent reservoir fl uids from exiting the wellbore. They are used in off-shore operations because of the risk of damage to the wellhead from atmospheric or anthropogenic phenom enon, such as a hurricane causing extensive platform damage or a ship coll iding with a platform. But in an onshore injection system, a down-hole shut-off sy stem will not determine or deter leakage of fluids in the wellbore and th erefore is not effect ive in protecting USDWs. Also, the likelihood of damage to an onshore wellhead is extremely remote. The greater risk in a Class VI onshore operation is that the mechanics of the down-hole shut-off system will be compromised or malfunction. Such a malfunction would require removal of the t ubing and shut-off system equipment, thereby creating a pot ential unwanted migrat ion path. The use of automatic downhole shut-off systems should be li mited to off-shore operations.

Furthermore, the requirement to continuous ly monitor the annulus fluid volume is impractical, because it does not provide a ny meaningful data regarding potential
p roblems with the operation of the well. Requiring the continuous monitoring of the amount of annulus fluid added during operations is more practical and will reveal potential leakage paths. Tx CCSA recommends the following:

§146.88(e) The owner or operator must install and use continuous recording devices to monitor: The injection pressure; the rate, volume, and temperature of the carbon dioxide stream; and the pressure on the annulus between the tubing and the long string casing and THE VOLUME OF annulus fluid added to the annulus VOLUME; and the owner or operator must install and use alarms and automatic DOWN-HOLE shut-off systems, designed to alert the operator and shut-in off the well when operatin g parameters such as annulus pressure, in j ection rate or other Commenter Name: Darrick Eu g ene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture a nd Storage Association Comment ID: 23986p arameters approved by the Director diverge beyond permitted ranges and/or gradients specified in the pe rmit. IF THE OPERATION INVOLVES OFF-SHORE INJECTION, THE OWNER OR OPER ATOR MUST INSTALL AND USE ALARMS AND AUTOMATIC DOWN-HOLE SHUT-OFF SYSTEMS, DESIGNED TO ALERT THE OPERATOR AND SHUT-IN THE WELL IF THE WELLHEAD IS DAMAGED OR WHEN OPERATING PARAMETERS SUCH AS ANNULUS PRESSURE, INJECTION RATE OR OTHER PARAMETERS

APPROVED BY THE DIRECTOR DIVERGE BEYOND PERMITTED RANGES AND/OR GRADIENTS SPECIFIED IN THE PERMIT;

(f) If aN down

- hole automatic shutdown is triggered or a loss of mechanical integrity is discovered, the owner of operator must immediately investigate and identify as expeditiously as possible the cause of the shutoff.

Response: After evaluating the risks and benefits of down-hole shut-off systems and considering additional research, EPA will not require automa tic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells install automatic surface shut-off devices. The rule afford s Director's discretion to mandate automatic downhole shut-off devices in onshore situations that may warrant their use.

The GS rule, at §146.88(e)(3), requires the installation of down-hole shut-off devices for Class VI wells located in the offshore submerged lands within the jurisdiction of a State UIC program. The Agency believes that the unique construc tion and operational conditions for offshore Class VI wells, including isolation from shorelines and the need to construct wells through the water column and the subsurface, may delay response time in the event of well diffi culties. These conditions merit requiring automatic down-hole shut-off devices fo r offshore wells in the submerged lands of a State.

EPA believes that requiring the inst allation of automatic surface shut-off devices for onshore wells (and affording Director's discretion to require down-hole devices where necessary) and automatic down-hole shut-off devices for offshore wells in submerged lands within the juri sdiction of a State ensures that
p roper precautions are taken to prevent subsurface fl uid movement and ensure protection of USDWs.

Regarding annulus fluid volume, EPA believes that knowing annulus fluid volume, as required at §146.88(e), is a necessary component of monitoring well mechanical integrity, but believes that monitoring the annulus fluid volume added is sufficient to meet the intent of continuous monitoring of the pressure on the annu lus. The final GS rule at §146.90 (b) re quires that owners or operators use continuous recording devices to monitor injection pressure, rate and vol ume; the pressure on the annulus between the tubing and the long string cas ing; and the annulus fluid volume added.

Other EPA Comment Codes and Descriptions: 4500 2.5 Proposed Mechanical Integrity Testing (MIT) Requirements (40 CFR 146.89) Comment: 7. § 146.89 Mechanical integrity.

EPA Proposed §146.89(c) At least once pe r year, the owner or operator must use one of the followin g methods to determine the absence of Commenter Name: Darrick Eu g ene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture and Stora g e Association Comment ID: 23987significant fluid moveme nt under paragraph (a)( 2) of this section: (3) A casing inspection log, if required by the Director.

Among the test protocols prescribed by the proposed rule to confirm lack of significant fluid movement is a casing inspection log. Although this log is optional, it may be require d by the Director. Conducti ng a casing inspection log will require the tubing to be pulled from a well, and that in turn substantially increases the possibility of a well cont rol event (that is a loss of control over well operation). Accordingly, the te chnique should only be mandated when other testing methodologies are unavailable . TxCCSA suggests the following edit:

§146.89(c) At least once per year, the owner or operator must use one of the following methods to determine the absence of significant fluid movement under paragraph (a)( 2) of this section: (3) A casing inspection log, if A TRAC ER SURVEY OR A TEMPERATURE OR N OISE LOG CANNOT BE OBTAINED AND A CASING INSPECTION LOG IS THUS required by the Director.

Response: EPA agrees that the casing inspection log is not an appropriate test to detect fluid movement behind the casing, but clarifies that it is a technique that can be used to determine the presence or absence of corrosion of the long-st ring casing, and is required if the Di rector determines that it is necessary based on site-specific information. EPA has revised the final GS rule to require that the frequency of the casing inspection log be specifie d in the approved testing and monitoring plan at §146.89(d).

Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: EPA Proposed §146.90(c) Corrosion monito ring of the well materials for loss of mass, thickness, cracking, pitt ing and other signs of corrosion must be performed on a quarterly basis to ensure that the well components meet the minimum standards for material strength and
p erformance set forth in § 146.86(b) by: (1) Placing coupons of the well constr uction materials in contact with the carbon dioxide stream; or (2) Routing the carbon dioxide stream through a loop co nstructed with the material used in the well; or (3) Using an alternative method approved by the Director;

TxCCSA believes the requirements in EPA proposed §146.90(c) related to corrosion monitoring are inapplicable. In the vast majority of cases, the CO2 will be transported to the injection site through pipelines, will be dehydrated prior to transportation and therefore when injected it will be non-corrosive.[FN2] In those instances, the test methods described in § 146.90(c)(1) and (c)(2) (except of course alternatives approved by the Dir ector) will not provide meaningful information regarding the mechanical in tegrity of down-hole casing, tubing and other equipment because the CO2 will simp ly not be corrosive at the surface. Consequently, to have any relevance such requirements should be reserved for situations where water satura ted CO2 is being injected. Commenter Name: Darrick Eu g ene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture a nd Storage Association Comment ID: 23989[FN2: For evidence on CO2 corrosivity in the absence of free water see Don Duttlinger, Enhanced Recove ry Intertwines Naturally With CO2 Sequestration, Tech Connections Column, January 2004, American Oil and Gas Reporter, available at http://www.pttc.org/aogr _columns_archived/aogrcojan04.htm (From the
p rocessing/injection standpoint , CO2 is noncorrosive as long as it is dry. Proving that point, Kinder Morgan has hydro- tested the 32-year-old CRC Pipeline built in 1971 to transport CO2. Only one minor failure occurred. After testing, the line was rated for 2,025 psi maximum ope rating pressure, which established a 200 psi increase over most recent ratings ); see J. Layne, Results of the Hydrotest of the 30-year old Canyon Reef Carriers CO2 Pipeline, 2003 CO2 Flooding Conference, December 11-12, 2003, Midl and,Texas (University of Texas of the Permian Basin’s Center for Ener gy and Economic Dive rsification).]

§146.90(c) Corrosion monitoring of the we ll materials for loss of mass, thickness, cracking, pitting and othe r signs of corrosion must be
p erformed on a quarterly basis to ensure that the well components THAT CONTACT WATER SATURA TED CARBON DIOXIDE STREAMS meet the minimum standards for material strength and performance set forth in § 146.86(b) by: (1) Placing coupons of the well constr uction materials in contact with the carbon dioxide stream; or (2) Routing the carbon dioxide stream through a loop co nstructed with the material used in the well; or (3) Using an alternative method approved by the Director. THE REQUIREMENTS OF THIS SUBPART ARE WAIV ED WHEN THE CARBON DIOXIDE STREAM IS DEHYDRATED

TO MEET PIPELINE SPECIFICATIONS.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has ma de many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

EPA disagrees with commenters' assertions that corrosion monitoring is unnecessary or excessive. CO2 in the presence of water (includi ng water with NOx, SOx, and H2S impurities) can be corrosive to well materials and cements. Thus, although a CO2 stream may be dry, the pot ential for corrosion of well materials down-hole, where th e injectate can potentially mix with water in the target formation, must be considered.

Several laboratory studies and a limi ted number of field studies have i nvestigated and characterized the effects of carbonic acid on well materials. Laborat ory studies (e.g., Kutchko et al., 2007; Kutchko et al., 2008) consistently identify alterations (typically car bonation) of cement as the result of interactions between cement and CO2-saturated brine. EPA believes that the testing methods specified in the rule are appropriate and have been used successfully by Cl ass I hazardous waste inje ction well owners or operators.

Currently, there are only a few analys es of cement from wells that have been in prolonged contact with CO2 in actual field (down-hole) c onditions. Evaluation of cement from a well at the Scurry Area Canyon Reef Operators Committee (SACROC) site show ed alteration, but did not show degradation that compromised the structural integrity of the ceme nt (Carey et al., 2007). In another study, cement samples were collected and analyzed from a CO 2 production well in a natural CO2 reservoir inColorado exposed to a CO2-water down-hole envir onment for 30 years (Crow et al., 2008). The study found evidence of reaction between th e CO2-rich water and the cement.

Oil industry research also addresses the effects of corrosion of steel tubing and pipes. Lopez et al. (2003) noted that 60 percent of oilfield failures are related to the effects of carbonic acid from produced brines on carbon and low alloy steels.

Laboratory investigation of cement alteration/degradation is an ongoi ng research area. Few field-based studies have been completed to date. The laboratory and field studies currently available suggest that corrosion problems can be managed; however, there is not a large e nough body of research to rule out
p otential corrosion problems of st eel components of injection well s. The IPCC (2005) report on carbon dioxide capture and storage reviewed oil and gas i ndustry experience with gas injection wells, close industry analogues to CO2 injection wells. The report st ated that while the design of CO2 injection wells will be very similar to gas injection wells, most down-hole components of the CO2 injection wells will “need to be upgraded for higher pressure ratings and corrosion resistance.” Given the pressure and corrosion considerations, anticipated long lifespan of a GS well and the difficulties that would be associated with a corrosion-relate d well failure, EPA believes thatcorrosion monitoring in the downhole environment is justified. For these reasons, the fi nal rule requires quarterly corrosion monitoring (at §146.90(c)).

The Agency plans to, every six years, collect and re view data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requi rements are appropriate or necessary.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: 9. § 146.92 Injection well plugging.

EPA Proposed §146.92 (b) Well Plugging Plan. (5) The type and grade and quantity of material to be used in plugging. The material must be compatible with the carbon dioxide stream;

The proposed regulation requires the well bore to be flushed prior to plugging and thus it is unnecessary to use cement "compatible with the carbon dioxide stream". In the absence of water, CO2 is non-corrosive and compatible with conventional cements (see discussion under Comment #7). Accordingly, the rule should be revised as follows:

§146.92 (b) Well Plugging Plan. (5) The type and grade and quantity of material to be used in plugging. The material must be compatible with the carbon dioxide stream;

Response: EPA believes, considering the pote ntially corrosive nature of CO2 when it is in contact with water, that the requirement that the material must be compatible with the CO2 stream is appropriate. The final rule retains this requirement because CO2 and water will be present in the subsurface. Commenter Name: Darrick Eugene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture and Stora g e Association Comment ID: 23992

Commenter Name: Darrick Eu g ene Letter ID: 0223Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93); 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Director affirmatively acts to extend th e post-injection site care period. These changes are contained in th e suggested text below:

§ 146.93 Post-injection site car e and site closure. (a) The owner or operator of a Class VI well must prepare, maintain, and comply with a plan for post-injection site care and site closure that meets the requirements of paragraph (a)(2) of this section and is acceptable to the Director. (1) The owner or operator must submit the post-injection site care and site closure plan as a part of the permit application to be approved by the Director. (2) The post-injection site care and site closure plan must include the following information: (i) The pressure differential between pre-injection and
p redicted post-injection pressu res in the injection zone; (ii) The predicted position of the carbon dioxide plume and associated pressure front at si te closure as demonstrated in the area of review evaluation required under § 146.84(b); (iii) A description of pos t-injection monitoring location, methods, and proposed frequency; and (iv) A proposed schedule for submitting post-injection site care monito ring results to the Director. (3) Upon cessation of injection, owne rs or operators of Class VI wells must either submit an amended post-injection site care and site closure plan or demonstrate to the Director through monitoring data and modeling results that no amendmen t to the plan is needed.(4) The owner or operator may modify and resubmit the postinjection site care and site closure plan for the Director’s approval within 30 days of such change. (b) The owner or operator shall monito r the site following the cessation of injection to show the positi on of the carbon dioxide plume and
p ressure front and demonstrate that USDWs are not being endangered. * * * (3) Prior to authorization for THE EXPIRATION OF THE PERIOD SPECIFIED IN SUBPART (B)(1), site closure , the owner or operator must submit to the Director a dem onstration, based on monitoring and other site specific data, that the carbon dioxide plume and pressure front have stabilized and that no a dditional monitoring is needed to assure that the geologic sequestration project does not pose an endangerment to USDWs. (4) IF WITHIN 180 DAYS AFTER THE SUBMITTAL OF THE DATA REQUIRED UNDER SUBPARAGRAPH (3), THE DIRECTOR DETERMINES THAT THE GEOLOGICAL SEQUESTRATION PROJECT MAY CONTINUE TO POSE AN ENDANGERMENT TO USDWS, HE SHALL SO NOTIFY THE OWNER OR OPERATOR OF HIS DETERMINATION AND THE BASIS THEREFORE, AND If such a demonstr ation cannot be made (i.e., if the Commenter Or g anization: Texas Carbon Capture and Stora g e Association Comment ID: 23994carbon dioxide plume and pressure front have not stabilized) after the 50

- year period, the owner or operator must submit to the Director a
p lan to continue post-injection site care. (5) IF WITHIN 180 DAYS AFTER THE SUBMITTAL OF THE DATA REQUIRED UNDER SUBPARAGRAPH (3) ABOVE THE DIRE CTOR FAILS TO DETERMINE AND TO N OTIFY THE OWNER OR OPERATOR THAT THE GEOLOGICAL SEQUESTRATION PROJECT MAY CONTINUE TO POSE AN ENDANGERMENT TO USDWS, SITE CLOSURE SHALL BE DEEMED AUTHORIZED BY RULE (c) Notice of intent for site closure. The owner or operator must notify the Director at least 120 days before si te closure. At this time, if any changes have been made to the origin al post- injection site care and site closure plan, the owner or opera tor must also provide the revised
p lan. At the discretion of the Direct or, a shorter noti ce period may be allowed. (d) After the Director ha s authorized site closur e OR SITE CLOSURE IS AUTHORIZED BY RULE, the owner or ope rator must plug all monitoring wells in a manner which will not allow move ment of injection or formation fluids that endangers a USDW. (e) Once the Director has authorized si te closure, OR SITE CLOSURE IS AUTHORIZED BY RULE, the owner or ope rator must submit a site closure report within 90 days that must thereafter be retained at a location designated by the Director. The report must include: (1) Documentation of appropriate injection and monitoring well
p lugging as specified in § 146.92 and para graph (c) of this section. The owner or operator must provide a copy of a survey plat which has been submitted to the local zoning authority designated by the Director. The
p lat must indicate the location of the injection well relative to
p ermanently surveyed benchmarks. The ow ner or operator must also submit a copy of the plat to the Regional Ad ministrator of the appropriate EPA Regional Office; (2) Documentation of appropriate notification and information to such State, local and tribal authorit ies as have authority over drilling activities to enable such State and local authorities to impose appropriate conditions on subsequent drilling activities that may
p enetrate the injection and confin ing zone(s); and (3) Records reflecting the nature, composition and volume of the carbon dioxide
stream. (f) Each owner or operator of a Class VI injection well must record a notation on the deed to th e facility property or any other document that is normally examined during title search that will in perpetuity provide any potential purchaser of the prope rty the following information: (1) The fact that land has been used to sequester carbon dioxide; (2) The name of the State agency, local authority, and/or tribe with which the survey plat was filed, as well as the address of the Regional Environmental Protection Ag ency Office to which it was submitted; and (3) The volume of fluid injected, the injection zone or zones into which it was injected, and the period over which injection occurred. (g) The owner or operator must reta in for three years following siteclosure, records collected during the post-injection si te care period. The owner or operator must deliver th e records to the Director at the conclusion of the retenti on period, and the records must thereafter be retained at a location designated by the Director for that purpose.

Response: The PISC requirements in the final GS ru le, as specified in §146.93(b), incorporate a combination of a fixed timeframe and a performance standard approach. EPA believes that a default PISC timeframe of 50 years, with Director's discretion to shorten or lengthen this timeframe, combined with a site-specific Director’s disc retion to create an alternative PISC time frame, ensures that USDWs are protected. The GS rule offers owners or operato rs flexibility regarding the duration of the PISC timeframe by: (1) allowing the Direct or discretion to shorten or lengt hen the PISC timeframe during the PISC period based on site-specific data, pursuant to requirements at §146.93(b) ; or (2) affording the Director discretion to allow a Class VI well owner or operator to demonstrate, based on substantial data during the permitting process, that an alternative PI SC timeframe may be appropriate if it ensures nonendangerment of USDWs pursuant to requirements at §146.93(c). EPA expects that the Director would consider the types of information the commenter describes in determining whether the plume and pressure front no longer pose a risk of endangerment to USDWs and
p ost-injection site care monitoring may be discontinued.

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts. EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and m onitoring wells; perform post-inject ion monitoring; demonstrate the appropriateness of an alternative pos t-injection site care time frame; demonstrate non endangerment; and
p erform site closure activities. The guidance will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements (seeking comment) Comment: HEI strongly supports, with one modificat ion discussed below, EPA’s actual language of the Proposed Rule in sect ion 146.86(b)(5), which establishes a reliable performance standard that will achieve protection of USDWs. Section 146.86(b)(5) states, "Cement and cement addi tives must be compatible with the carbon dioxide stream and formation fluids and of sufficient quality and quantity to maintain integrity over the design life the geologic sequestration
p roject." HEI recommends that EPA’s discussion in the Preamble should be consistent with the actual language of th e Proposed Rule to ensure clarity and remove any ambiguity regarding the perfor mance-based approach set forth in the Proposed Rule. Commenter Name: Tiffan y Rau Letter ID: 0224 Commenter Or g anization: Hydrogen Energy International Comment ID: 21681Response: The final rule does not specifically require the use of aci d -resistant cements, but it requires at §146.86(b)(5) that cement and cement additives be co mpatible with the CO2 stream and formation fluids and of sufficient quality a nd quantity to maintain integrity ove r the design life the GS project. Both field and laboratory studies have found acid alteration where trad itional well cements have been used for CO2 injection. Although the laboratory and field studies suggest that corrosion problems may not be severe, such problems cannot be conclusively ruled out, and the amount of available data on this
p roblem is still relatively small. Laboratory investigation of cement degradation is an ongoing research area, and field- b ased studies are very few. There also does not appear to be a clear consensus at this time on the corrosion risks for the steel components of inje ction wells. Given the anti cipated long lifespan of a Class VI well and the difficulties that would be associated with a corrosion-related well failure, EPA believes that the construction requi rements at §146.86 are justified.

EPA clarifies that the requirement at §146.86(b)(5) is that cement and cemen t additives must be compatible with the CO2 stream and formation fluids and of sufficient quality and quantity to maintain integrity over the design li fe of the GS project.

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4520 2.5.1 Continuous internal mechanical integrity monitoring (seeking comment) Comment: The frequency of the monitoring should be defined not as "continuous" but as "regular" or "periodic" based upon si te characteristics because regular monitoring (e.g., every minute or hour) will often be adequate. For example, fluid volume in the annulus is static and requires evaluation of a pressure
p ulse to determine the depth of top of fluid. Therefore, this should be monitored on a monthly or quarterly basis to support the pressure data.

Response: EPA believes that continuous pressure monitori ng of GS wells, instea d of periodic testing, which is required for most other types of deep inj ection wells is appropriate because the potentially corrosive nature of CO2 injectate streams in the pr esence of water enables the immediate identification of corrosion-related internal mechanical integrity problems that could lead to significant well problems and failure. Continuous monitoring was found to be very important in an EPA study of UIC Class I internal MIT failure rates and causes (USEPA 1993). The study reviewed MIT results over a 5 year
p eriod and found 135 MIT failures in 428 wells (a single well can have more than one MIT failure). In all cases, the MIT failures we re found through continuous annulus monitoring which served the important role of an early warning to prevent any well failure. Class VI injection wells must be equipped with dedicated computer-based c ontinuous pressure monitoring devices in concert with the shut-off systems required for GS wells, whic h typically take readings several times per second and record them electronically in a computer system. 40 CFR §146.91(a)(2) requires that monthly averages of the continuous annulus monitoring be reported on a semiannual basis.

EPA believes that monitoring of annulus fluid volume is an important method for verifying that the well system is intact, and knowing the annulus fluid vol ume is necessary for moni toring annulus pressure. While this requirement has until now been limited to Class I hazardous waste injection wells, the high volumes and supercriti cal nature of the in j ectate, the potential g eomechanical stresses in the wellbore, Commenter Name: Tiffan y Rau Letter ID: 0224 Commenter Or g anization: H y dro g en Ener gy International Comment ID: 21693and the potential for movement of the buoyant CO2 in th e event of a MI loss make it an important safety consideration for GS projects. Continuous pressure monitoring allows imme diate identification of corrosion-related well integrity loss. EPA agrees with the commen ter that recording annulus fluid volume may not be appropriate. However, EPA believes that knowing annulus fluid volume required at §146.88(e) is a necessary component of monitoring well mechanical integrity, but believes that knowing the annulus fluid volume added is su fficient to meet the intent of the requirement. The final GS rule requires that owners or operators use continuous reco rding devices to monitor injection pressure, rate and volume; as well as the pressure on the annulus between the tubing and the long string casing. It also modifies the requirement in the proposed rule to continuously monitor annulus fluid volume; it now requires recording of annulus fluid volume added §§146.88(e); 146.89(b); and 146.90 (b).

Fluid level can be detected us ing acoustic techniques (Schubert , 1998). The Texas Class I well regulations for industrial wells curre ntly require continuous monitoring of annulus pressure and volume, and the majority of injection wells in Ohio c onduct continuous monitoring (G WPC, 2006). At least one commenter indicated that the technology required for continuous monito ring is currentl y available and should not present an undue cost burden. Continuous annulus monitoring is also conducted at the commercial-scaled carbon capture a nd geologic sequestration operation at the In Salah, Algeria natural gas plant where more than 3 million tons of CO 2 have been sequestered since 2004. The technology for continuous monitoring is available, is currently in fairly wide use, and the costs are not burdensome, especially given the operational and safety considerations addressed.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements (seeking comment) Comment: BP strongly supports, with one modificat ion discussed below, EPA’s actual language of the Proposed Rule in sect ion 146.86(b)(5), which establishes a reliable performance standard that will achieve protection of USDWs. Section 146.86(b)(5) states, "Cement and cement addi tives must be compatible with the carbon dioxide stream and formation fluids and of sufficient quality and quantity to maintain integrity over the design life the geologic sequestration
p roject." BP recommends that EPA’s di scussion in the Preamble should be consistent with the actual language of th e Proposed Rule to ensure clarity and remove any ambiguity regarding the perfor mance-based approach set forth in the Proposed Rule.

Response: The final rule does not specifically require the use of acid-resistant cements, but it requires at §146.86(b)(5) that cement and cement additives be co mpatible with the CO2 stream and formation fluids and of sufficient quality a nd quantity to maintain integrity ove r the design life the GS project. Both field and laboratory studies have found acid alteration where trad itional well cements have been used for CO2 injection. Although the laboratory and field studies suggest that corrosion problems may not be severe, such problems cannot be conclusively ruled out, and the amount of available data on this
p roblem is still relatively small. Laboratory investigation of cement degradation is an ongoing research area, and field- b ased studies are very few. There also does not appear to be a clear consensus at this time on the corrosion risks for the steel components of inje ction wells. Given the anti cipated long lifespan of a Class VI well and the difficulties that would be associated with a corrosion-related well failure, EPA believes that the construction requi rements at §146.86 are justified.

EPA clarifies that the requirement at §146.86(b)(5) is that cement and cemen t additives must be compatible with the CO2 stream and formation fluids and of sufficient qualit y and quantit y to maintain Commenter Name: Brian Williams Letter ID: 0225 Commenter Or g anization: BP Alternative Ener gy North America, Inc. (BP) Comment ID: 21731integrity over the design li fe of the GS project.

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: 1. Schlumberger asks that the EPA expand th e applicability of Class VI wells to cover wells injecting CO2 th at is dissolved in water or brine. The current draft language for Section 146.81(b) states:

This subpart applies to wells used to inject carbon dioxide specifically for the purpose of geologic sequest ration, i.e., the long-term containment of a gaseous, liquid or s upercritical carbon dioxide stream in subsurface geol ogic formations.

We suggest that the EPA replace the cu rrent language with the following language:

This subpart applies to wells used to inject carbon dioxide specifically for the purpose of geologic sequest ration, i.e., the long-term containment of a gaseous, liquid or s upercritical carbon dioxide stream or carbon dioxide dissolved in water or brine into subsurface geologic formations.

While we recognize today the injection of dissolved CO2 raises economic challenges we feel that there may be cases where the injection of dissolved CO2 will make sense both in terms of econom ics and in terms of leakage risk. Unlike separate phase CO2, CO2 dissolved in water is not less dense than the formation fluid and will not be s ubject to buoyancy driven leakage.

Response: EPA disagrees with the suggested change. §146.81(b) reads as follows: “This subpart applies to any wells used to inj ect carbon dioxide specifical ly for the purpose of geologic sequestration, i.e., the long-term containment of a gase ous, liquid, or supercritical carbon dioxide stream in subsurface geologic formations.” Nothing in th e rule precludes the injection of dissolved CO2, as long as the CO2 does not meet the definition of a hazardous waste under 40 CFR part 261.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 5260 2.8.2.3 Adjusting the post-injection timeframe (seeking comment); 5300 2.8.3 Site clos ure activities (40 CFR 146.93) Comment: 3. Schlumber g er does not support the default post in j ection site care period of Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 23996

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 2399850 years. We feel that because the ch aracterization and ope ration of the site will be based on the specific attributes of the site that the length of post injection site care should also be site sp ecific information. In particular the criteria for ending the PISC period s hould be based on site performance and risk. We support the idea that the direct or approves final site closure. We suggest the following language for Section 146.93(b)(1):

(1) The owner or operator shall c ontinue to conduct monitoring as specified in the Director-approved pos t-injection site care and site closure plan, pursuant to the performance based criteria described in 146.93(b)(3).

We suggest the following langua ge for section 146.93(b)(2)

(2) If the owner or operator can dem onstrate to the satisfaction of the Director that the geologic sequest ration project no longer poses an endangerment to USDWs, the Director may approve an am endment to the
p ost- injection site care and site closure plan to reduce the frequency of monitoring or ma y authorize site closure.

And we suggest the following la nguage for section 146.93(b)(3)

(3) Prior to authorization for site closure, the owner or operator must demonstrate to the Director, base d on monitoring and other sitespecific data that no additional monitoring is needed to assure that the geologic sequestration project does not pose an endangerment to USDWs, considering the following:.

(i) the estimated magnitude and extent of the AOR based on measurements and modeling; (ii) that CO2 movement and pressure changes match model
p redictions, (iii) the estimated locat ion of the detectable CO2 plume based on measurement and modeling (m easuring magnitude of saturation within the plume or mapping the edge of it); (iv) that there is no evidence of significant leakage of eith er CO2 or formati on fluids that endanger USDWs; (v) that the CO2 plum e and displaced formation fluid are not expected to migrate in the futu re in a manner that encounters a
p otential leakage pathway; and, (vi) that wells at the site are not leaking and have maintained integrity.

Response: The PISC requirements in the final GS ru le, as specified in §146.93(b), incorporate a combination of a fixed timeframe and a performance standard approach. EPA believes that a default PISC timeframe of 50 years, with Director's discretion to shorten or lengthen this timeframe, combined with a site-specific Director’s disc retion to create an alternative PISC time frame, ensures that USDWs are protected. The GS rule offers owners or operato rs flexibility regarding the duration of the PISC timeframe by: (1) allowing the Direct or discretion to shorten or lengt hen the PISC timeframe during the PISC period based on site-specific data, pursuant to requirements at §146.93(b) ; or (2) affording the Director discretion to allow a Class VI well owner or operator to demonstrate, based on substantial data during the permitting process, that an alternative PI SC timeframe may be appropriate if it ensures nonendangerment of USDWs pursuant to requirements at §146.93(c).

EPA expects that the Director would consider the types of information the commenter describes indetermining whether the plume and pressure front no longer pose a risk of endangerment to USDWs and
p ost-injection site care monitoring may be discontinued.

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts.

EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and m onitoring wells; perform post-inject ion monitoring; demonstrate the appropriateness of an alternative pos t-injection site care time frame; demonstrate non endangerment; and
p erform site closure activities. The guidance will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4650 2.6.5 CO2 plume and pressure front tracking (seeking comment) Comment: 4. Schlumberger supports the concept of te sting and monitoring to track the CO2
p lume and the associated pressure front. We feel that without this monitoring the validation and updating of the models used to predict the size and shape of the AOR cannot be properly conducted and that the use of models to predict the size and shape of the AOR will be ineffective. However we feel that the language in section 146.90(g) is too restri ctive. The current language states:

(g) Testing and monitoring to track the extent of the carbon dioxide
p lume and the position of the pressu re front by either monitoring for
p ressure changes in the first formatio n overlying the confining zone or using indirect, geophysical techni ques (e.g., seismic, electrical, gravity, or electromagnetic surveys and/or down-hole carbon dioxide detection tools);

We feel that the restrictions placed in this language could adversely impact the efficiency of monitoring and modeling depending on site conditions. Schlumberger proposes the fo llowing alternate language:

(g) Testing and monitoring to track the extent of the carbon dioxide
p lume and the position of the pressu re front by either monitoring for
p ressure changes, using geophysical techniques (e.g., seismic, electrical, gravity, or el ectromagnetic surveys and/or down-hole carbon dioxide detection tools), other t echniques that are approved by the director or a combination of tec hniques if multiple techniques are deemed necessary by the director; Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 23999Response: EPA has revised this requirement in the fina l rule. The final GS regulation, at §146.90(g)(1), requires all GS project owners or operators to monitor directly for pressure changes in the injection zone. EPA believes that pressure m onitoring in the injection zone is necessary to track the development and movement of the pressure front and CO2 pl ume. In addition, §146.90(g)(2) requires owners or operators to track the position of the CO2 plume using indirect methods (e .g., seismic, electrical, gravity, or electromagnetic survey s and/or down-hole CO2 detection tools), unless the Director determines based on site-specific geology, that such methods are no t appropriate. EPA is affording Director's discretion rega rding the use of geophysical techniques at some sites because the Agency recognizes that geophysical methods ar e not appropriate in all geologic settings. EPA clarifies that this determination will be made by the Director based on the site-specifi c geologic information submitted by the owner or operator with their permit application.

EPA believes that this approach provides flexibilit y to develop a site-specific monitoring plan, ensures that direct monitoring is avai lable to track the movement of the CO2 and validate models, and recognizes that indirect techniques are not appropriate in all situ ations. The owner or operator's approved testing and monitoring plan will include th e site-specific details, technologies, testing and monitoring frequencies, and other pertinent information.

EPA is developing guidance on testing and monitoring to assist owners or opera tors and Directors in evaluating requirements under §146.90, in cluding proposed monitoring pl ans. The guidance describes available technologies and recommended approaches for implementing a test ing and monitoring plan, including pre-operational geophys ical logging and test ing of injection wells, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost USDW Comment: §144.6 Classification of wells.

Proposed Rule:(f) Class VI. Wells used for geologic sequest ration of carbon dioxide beneath the lowermost formation containing a USDW.

Schlumberger Suggested Revision: (f) Class VI. Wells used for geologic sequestration of carbon dioxide.

Schlumberger Rationale: We feel that seque stration can be conducted safely above USDWs as evidenced by the class 2 EOR expe rience. Also, the rest riction to below the lowest USDW rules out many potential CCS sites.

Response: EPA acknowledges that there are limited circum stances where injectio n above the lowermost USDW can be performed in a manner that protects USDWs from endangerment, as long as appropriate
p rotections are in place. The fina l GS rule at §146.95 establishes a pro cess by which owners or operators can seek a waiver of the Class VI injection depth requirements for injection into non-USDW formations above and/or between USDWs. It establishes: 1) requirements specifying information that owners or operators must submit, and Director s must consider, in consultation wi th PWSS Directors; 2) procedures for public notice of a waiver application and for Directo r -Re g ional Administrator communication; 3) the Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24006waiver issuance process; and, 4) a dditional requirements that apply to owners or operators of Class VI wells granted a waiver of the injection depth requir ements to ensure USDW protection above and below the injection zone.

EPA adds that it has revised the definition of a Class VI well to read as follows: “Wells that are not experimental in nature that are used for geologic sequestration of carbon dioxide beneath the lowermost formation containing a USDW; or, wells used for ge ologic sequestration of carbon dioxide that have been granted a waiver of the in jection depth requirements pursuant to requirements at §146.95 of this chapter; or, wells used for geologi c sequestration of carbon dioxide that have received an expansion to the areal extent of an existing Class II enhanced oil recovery or enhanced gas recovery aquifer exemption pursuant to §§146.4 of this chapter and 144.7(d).”

For additional information on the waiv er approach, please se e the final rule and preamble, as well as EPA's responses to comments on the Notice of Da ta Availability and Request for Comment.

Other EPA Comment Codes and Descriptions: 2066 1.5.3.3 Grandfathering construction of Class V wells (seeking comment) Comment: §144.15 Prohibition of non-experimental Class V wells for geologic sequestration.

Proposed Rule: The construction, opera tion or maintenance of any nonexperimental Class V geologic se questration well is prohibited.

Schlumberger Suggested Revision: -

Schlumberger Rationale: We agree, there should be only one class of geologic sequestration well but CO2 class V wells should be grandfathered.

Response: EPA agrees that many Class V experimental technology wells are designed and constructed to withstand exposure to CO2. The final GS rule provides for th e construction of these wells to be grandfathered per §146.81(c) , provided the owner or operator can de monstrate to the Director that the wells were engineered and constructed to meet th e requirements at §146.86(a) and ensure protection of USDWs, in lieu of requirements at §146.86(b) a nd §146.87(a). EPA clarifies th at only the construction requirements are grandfathered a nd that all other Class VI requirements (reporting, monitoring, mechnical integrity testing, etc.) must be met following a determination under §146.81(c).

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost USDW Comment: §146.5 Classification of injection wells.

Proposed Rule:(f) Class VI. Wells used for geologic sequest ration of carbon dioxide beneath the lowermost formati on containing an underground source of drinking water (USDW).

Schlumber g er Su gg ested Revision: (f) Class VI. Wells used for g eolo g ic Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24007

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24008sequestration of carbon dioxide.

Schlumberger Rationale: We feel that seque stration can be conducted safely above USDWs as evidenced by the class 2 EOR expe rience. Also, the rest riction to below the lowest USDW rules out many potential CCS sites.

Response: Please see the response to the commenter’s suggested revision to §144.6(f).

Other EPA Comment Codes and Descriptions: 2060 1.5.3 Comments on grandfathering of existing wells (seeking comment); 3800 2.3 Proposed Injection Well Construction Requirements (40 CFR 146.86) Comment: §146.81 Applicability.

Proposed Rule: (c) This subpart applies to owners and operators of permit or rule-authorized Class I indus trial, Class II, or Class V experimental carbon dioxide injection projects who seek to apply for a Class VI geologic sequestration permit for their well or wells. If the Director determines that USDWs will not be endangered, such we lls are exempt, at the Director’s discretion, from the casing and cement ing requirements at §§146.86(b) and 146.87(a)(1) through (3).

Schlumberger Suggested Revision: (c) Th is subpart applies to owners and operators of permit or rule-authorized Cl ass I industrial, Class II, or Class V experimental carbon dioxide injection projects who seek to apply for a Class VI geologic sequestration permit for their well or wells. If the Director determines that USDWs will not be enda ngered, such wells are exempt, at the Director’s discretion, from the casing and cementing requirements at §§146.86(b) and 146.87(a)(1) through (3) if the wells we re constructed prior to January 1, 2010.

Schlumberger Rationale: We feel that ther e needs to be a cutoff date for the grandfathering of wells so eventually all Class 6 wells are constructed to the same standard

Response: EPA agrees that many Class I, Class II, and Class V experimental technology wells are designed and constructed to withstand exposure to CO 2. The final GS rule provides for the construction of these wells to be grandfathe red per §146.81(c), provided the owner or operator can demonstrate to the Director that the wells were engineered and constructed to meet the requirements at §146.86(a) and ensure protection of USDWs, in lieu of requi rements at §146.86(b) and §146.87(a). EPA clarifies that only the construction requirements ar e grandfathered and that all othe r Class VI requirements (reporting, monitoring, mechanical integrity testing, etc.) mu st be met following a determination under §146.81(c).

EPA does not plan to institute a "cut-off date" for this requirement since conversion is a site-specific decision. EPA believes that the requirement should be based on the specific aspects of the well's construction, not on the date on which it was constructed. Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24009

Commenter Name: Andrew Du g ui d Letter ID: 0226Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: Proposed Rule: Carbon dioxide stream means carbon dioxide that has been captured from an emission source (e.g., a power plant), plus incidental associated substances derived from th e source materials and the capture process, and any substances added to the stream to enable or improve the injection process. This subpart does not apply to any carbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.

Schlumberger Suggested Revision:: Carbon di oxide stream carbon dioxide that has been captured from an indus trial process that is injected in any physical state or dissolved in water or brine. It includes incidental associated substances derived from the source materials and th e capture process, and any substances added to the stream to enable or improve the injection process. This subpart does not apply to any carbon dioxide str eam that meets the definition of a hazardous waste under 40 CFR part 261.

Schlumberger Rationale: We want to ensure that dissolved CO2 is specifically allowed as it may allow a solution to th e upward buoyancy drive associated with separate phase CO2.

Response: EPA disagrees with the suggested edit. The fi nal definition of car bon dioxide stream at §146.81(d) remains unchanged and reads as: “carbon dioxide that has be en captured from an emission source (e.g., a power plant), plus inci dental associated substances derived from the source materials and the capture process, and any substances added to the stream to enable or impr ove the injection process. This subpart does not apply to any carbon dioxide st ream that meets the defi nition of a hazardous waste under 40 CFR part 261.” As described above, nothing in the rule precludes the injection of dissolved CO2, as long as the CO2 does not meet the defi nition of a hazardous waste under 40 CFR part 261.

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment EPA has made many revisions to the GS rule. Please see the final rule and
p reamble for additional information.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: Proposed Rule:Geologic sequestration mean s the long-term containment of a gaseous, liquid or supercri tical carbon dioxide stream in subsurface geologic formations. This term does not apply to its capture or transport.

Schlumberger Suggested Revision: Geologic sequestration means the long-term containment of a carbon dioxide stream in subsurface geologic formations. This term does not apply to its capture or transport.

Schlumberger Rationale: CO2 stream was al ready defined and should e used here.

Response: EPA disagrees with the suggested change. The final definition of ge ologic sequestration at §146.81(d) reads as follows: “[T]he long-term containment of a gaseous, liquid, or supercritical carbon dioxide stream in subsurface geol ogic formations. This term does not apply to carbon di oxide capture or transport.” Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24010

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24011Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: Proposed Rule: Geologic sequestration project means an injection well or wells used to emplace a carbon dioxide stre am beneath the lowermost formation containing a USDW. It includes the subsur face three-dimensional extent of the carbon dioxide plume, associated pressure front, and displa ced brine, as well as the surface area above that delineated region.

Schlumberger Suggested Revision: Geol ogic sequestration project means an injection well or wells used to em place a carbon dioxide stream into an injection zone. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displa ced brine, as well as the surface area above that delineated region.

Schlumberger Rationale: -

Response: The Agency has modified the definition of geologic sequestration project at §146.81(d) to read as follows: “Geologic sequest ration project means an injection we ll or wells used to emplace a carbon dioxide stream beneath the lo wermost formation containing a USDW; or, wells used for geologic sequestration of carbon dioxide that have been granted a waiver of the injection depth requirements
p ursuant to requirements at §146.95; or, wells used for geologic sequestration of carbon dioxide that have received an aquifer exemption expansion. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surface area above that delineated region.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: Proposed Rule: Injection zone means a ge ologic formation, group of formations, or part of a formation that is of suff icient areal extent, thickness, porosity, and permeability to receive carbon dioxide through a well or wells associated with a geologic sequestration project.

Schlumberger Suggested Revision: Inject ion zone means a geologic formation, group of formations, or part of a formation that is of sufficient areal extent, thickness, porosity, and permeability to receive carbon dioxide through a well or wells associated with a geologic sequestration project.

Schlumber g er Rationale: - Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24012

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24013Response: EPA disagrees with the suggested edit. Th e definition of injection zone at §146.81(d) remains unchanged and reads as follows: “[A] geologi c formation, group of form ations, or part of a formation that is of sufficient areal extent, thickness, porosity, a nd permeability to receive carbon dioxide through a well or we lls associated with a geologic sequestration project.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: Proposed Rule: Pressure front means the zone of elevated pressure that is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressure differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.

Schlumberger Suggested Revision: Pressure front means the zone of elevated
p ressure that is created by the injecti on of the carbon dioxide stream into the subsurface, where there is a pressure diff erential sufficient to cause movement of the carbon dioxide stream or formation fluids into a USDW.

Response: EPA disagrees with the suggested edit. The final definition of pressure front at §146.81(d) is unchanged and reads as follows: “[T] he zone of elevated pressure th at is created by the injection of carbon dioxide into the subsurface. For the purposes of this subpart, the pressure front of a carbon dioxide plume refers to a zone where there is a pressu re differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: Proposed Rule: Site closure the point/tim e, as determined by the Director following the requirements under §146.93, at which the owner or operator of a GS site is released from post-injection site care responsibilities.

Schlumberger Suggested Revision: Site closure means the point/time, as determined by the Director following the requirements under §146.93, at which the owner or operator of a GS project is released from post-injection site care responsibilities.

Schlumberger Rationale: Sugge st using "GS project" to be consistent with other definitions Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24014

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24015Response: EPA disagrees with the suggested edit. The final definition of site closure at §146.81(d) is unchanged and reads as follows: “The point/time, as determined by the Director following the requirements under §146.93, at which the ow ner or operator of a GS site is released from post-injection site care responsibilities.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: Proposed Rule: Transmissive fault or fract ure means a fault or fracture that has sufficient permeability and vertical exte nt to allow fluids to move between formations.

Schlumberger Suggested Revision: Transmissive fault or fracture means a fault or fracture that has sufficient permeability a nd vertical extent to allow fluids to move beyond the confining zone.

Schlumberger Rationale: The term between fo rmations is insuffic ient as it could also include multiple zones within a inj ection zone or between two zones above the confining unit.

Response: EPA disagrees with the suggested edit. The final definition of tran smissive fault or fracture at §146.81(d) is unchanged and reads as foll ows: “[A] fault or fra cture that has suffic ient permeability and vertical extent to al low fluids to move between formations.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: §146.82 Required Class VI pe rmit information.

Proposed Rule: (b) A map showing the inj ection well(s) for wh ich a permit is sought and the applicable area of review . Within the area of review, the map must show the number, or name and loca tion of all injection wells, producing wells, abandoned wells, plugged wells or dry holes, deep stratigraphic boreholes, State or EPA a pproved subsurface cleanup sites, surface bodies of water, springs, mines (surface and subsu rface), quarries, water wells and other
p ertinent surface features including structures intended for human occupancy and roads. The map should also show faults, if known or suspected. Only information of public record is required to be included on this map;

Schlumber g er Su gg ested Revision: (b) A map or electronic file (e. g . GIS file) Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24016

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24017showing the injection well(s) for which a permit is sought and the applicable area of review. Within the area of review, the map must show the number, or name and location of all injection wells, pr oducing wells, abandoned wells, plugged wells or dry holes, deep stratigraphi c boreholes, State or EPA approved subsurface cleanup sites, surf ace bodies of water, springs, mines (surface and subsurface), quarries, water wells and other pertinent surface features including structures intended for human occ upancy and roads. The map should also show faults, if know n or suspected with surface expressions. Only information of
p ublic record is required to be included on this map;

Schlumberger Rationale: This may mean mo re clarification. It seems strange to have deep faults on a surface map. Is th e map to be of the surface or of the confining unit? Also, any map will be very busy so it may be us eful to be able to submit an electronic file like a GIS file.

Proposed Rule: (c) The area of review based on modeling, using data obtained during logging and testing of the well and the formation as required by
p aragraphs (l), (r), and (s) of this section;

Schlumberger Suggested Revision: -

Schlumberger Rationale: We support this but it may need to be better clarified that the well must e drilled pr ior to the permit application

Proposed Rule: (3) Information on seismi c history including the presence and depth of seismic sources and a determin ation that the seismicity would not interfere with containment;

Schlumberger Suggested Revision: (3) Info rmation on seismic history of the area including the presence and dept h of seismic sources and a determination that the seismicity would not interf ere with containment;

Schlumberger Rationale: It seems like this requirement is at a larger scale than the AOR (maybe a regi onal scale) than the other re quirements. This should be specified.

Proposed Rule: (4) Data on the depth, areal extent, thickness, mineralogy,
p orosity, permeability and capillary pressure of the injection and confining zone(s); including geology/facies changes based on field data which may include geologic cores, outcrop data, seismic su rveys, well logs, and names and lithologic descriptions;

Schlumberger Suggested Revision: (4) Data on the depth, areal extent, thickness, mineralogy, porosity, permeabili ty and capillary entry pres sure of the injection and confining zone(s); including geology/ facies changes based on field data which may include geologic cores, outcrop da ta, seismic surveys, well logs, and names and lithologic descriptions;

Schlumberger Rationale: Should this incl ude capillary pressure or capillary entry pressure?Proposed Rule: (e) A tabulation of all we lls within the area of review which
p enetrate the injection or confining z one(s). Such data must include a description of each well's type, cons truction, date drilled, location, depth, record of plugging and/or completion, and any addi tional information the Director may require;

Schlumberger Suggested Revision: -

Schlumberger Rationale: How will this be handled if all of this data is not available for each well?

Proposed Rule: (f) Maps and stratigraphic cross sections indicating the general vertical and lateral limits of all USDW s, water wells and springs within the area of review, their positions relative to the injection zone(s) and the direction of water movement, where known;

Schlumberger Suggested Revision: In

Schlumberger Rationale: -

Proposed Rule: (g) Baseline geochemical data on subsurface formations, including all USDWs in the area of review;

Schlumberger Suggested Revision: (g) Ba seline geochemical data on subsurface formations, including all USDWs and geoc hemically monitored in the area of review;

Schlumberger Rationale: All formations that are or may need to be geochemically monitored should be included

Response: EPA agrees that deep faults would not be expressed on a surface map, but information on such faults should be provided in cr oss sections, which are also required as part of the materials that support a permit application.

EPA agrees that submittal of support information electronically is beneficial. The final GS rule requires owners or operators to submit permit applications, including supporting information, to EPA in an electronic format (§146.91(e)).

Regarding seismic information, EPA ac knowledges that, due to the nature of seismic events and records, available information would likely a ddress an area that is larger than the delineated AoR. EPA clarifies that the intent of this requirements is to ensure that the Director ha s sufficient information on which to base a determination of the suitability of a potential project site for GS.

EPA clarifies that information on cap illary entry pressure must be s ubmitted. EPA believes that capillary entry pressure measurements on co re samples are necessary to quant ify the amount of buoyant force the confining zone can maintain before failure (World Resources Institute, 2008).

Regarding the requirement to submit tabulations of all wells within the AoR, EPA acknowledges that
p ublic records may not contain data on every artificial penetration in th e AoR (or all of the data on each well that is required for the tabulat ion), particularly in areas with ma ny older wells. However, EPA notes that the inventory and review pr ocess for GS wells required at §146.84( c)(2) is similar to what isrequired of Class I and Class II injection well operators, that the AoR and corrective action process for these well types has been successful for many years. EPA adds that the Director has the discretion to require the owner or operator to supplement a da ta records search, incl uding requiring ground or airborne surveys for wells, if there is reason to believe, based on knowle dge of the site or of available data bases, that the incompletene ss of available information could compromise USDW protection from endangerment.

Regarding baseline geochemical data, EPA is not specifying for which format ions this information should be submitted to allow flexibility, but examples may include the following formations: a) the injection zone, b) the confining z ones, c) containment zones above the confining zones in which any
p otentially migrating CO2 could be trapped, d) all USDWs, and e) any other geologic zone or formation that is important to the proposed monitoring program. The Director has the authority to request additional geochemical data as well.

EPA agrees that not all of the in formation listed at §146.82 of the propos ed regulation will be available at the time the owner or operator develops their initial pe rmit application. In response to comments and based on an evaluation of the proposed requirements at §146.82, the Agency revised this subpart so that the final regulation specifi es separate requirements for information to be submitted with the permit application and before well construction is approved (at §146.82(a)) and inform ation to be submitted before operation of the well is authorized (at §146.82(c)).

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators and Directors in evaluating permit requirements and applications under §146.82. The guidance provides recommendations regarding charac terizing the regional geology and hydr ogeology of a proposed GS site as well as performing the necessary geochemical, geomechanical, and geophys ical analyses of the injection and confining zone. The guida nce can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: §146.83 Minimum criteria for siting.

Proposed Rule: (2) A confining zone(s) that is free of transmissive faults or fractures and of sufficient areal extent and integrity to contain the injected carbon dioxide stream and displaced format ion fluids and allow injection at
p roposed maximum pressures and volume s without initiati ng or propagating fractures in the confining zone(s); and

Schlumberger Suggested Revision: -

Schlumberger Rationale: We support this language as it is written.

Response: EPA acknowledges the comment and the final ru le retains the text at §146.83 as proposed.

Other EPA Comment Codes and Descriptions: 3120 2.1.2 Need to identif y additional confinin g and Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24018

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24019containment zones (seeking comment) Comment: Proposed Rule: (b) At the Director’s discretion, owners or operators of Class VI wells must identify and characterize additional zones that will impede vertical fluid movement, are free of faults a nd fractures that may interfere with containment, allow for pressure dissipation, and provide additional opportunities for monitoring, mi tigation and remediation.

Schlumberger Suggested Revision: (b) Owners or operators of Class VI wells must identify and characterize some additional zo nes, if they exist, that will impede vertical fluid movement, allow for pres sure dissipation, and provide additional opportunities for monitoring, mitigation and remediation. Vertical faults and fractures that transect these zones must be identified.

Schlumberger Rationale: We believe that a site with a single confining can
p rovide storage integrity, however, we feel that if there are additional confining layers at the site they shoul d be characterized to get a better estimate of leakage risk to USDWs and possibly identify additional monitoring

zones.

Response: EPA retains the requirement to identify additi onal containment/confining zones, if required by the Director, as proposed (§146.83(b)). EPA acknowledges that such additional zones may not be needed in all circumstances, and clarifies that this requirement is at the Di rector's discretion, based on his or her understanding of a particular site. EPA beli eves that, in some situations, the presence of additional confining and containment zones above th e primary (i.e., lowermost) confining zone can improve USDW protection. These laye rs could further impede vertical fluid movement and allow for
p ressure dissipation, and also provi de additional sites for monitori ng, mitigation, and remediation. The Agency's decision is supported by commenters represen ting states, water associat ions, and an electric utility who assert that these requi rements promote a flexible, risk-b ased, site-specific approach to characterizing and permitting a site for GS project s, and are intended to improve understanding of the
p roject as a whole and promote better modeling of the site.

Other EPA Comment Codes and Descriptions: 3200 2.2 Proposed Area of Review and Corrective Action Requirements (40 CFR 146.84) Comment: §146.84 Area of review and corrective action.

Proposed Rule: (a) The area of review is the region surrounding the geologic sequestration project that may be impact ed by the injection activity. The area of review is based on computational modeling that accounts for the physical and chemical properties of all phases of the injected carbon dioxide stream.

Schlumberger Suggested Revision: (a ) The area of review is based on computational modeling that accounts for physical and the chemical properties of all phases of the injected carbon dioxide stream, the associated pressure front, and displaced brine.

Schlumberger Rationale: -

Response: Based on review of all public comments on the AoR definition at 146.84(a), the A g enc y has Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24020modified it to read as follow s: The region surrounding the geologic sequestration project where USDWs may be endangered by the injection activity. The ar ea of review is delineat ed using computational modeling that accounts for the physical and chemical properties of all pha ses of the injected CO2 stream and is based on available site characterization, monitoring, and operational data. The definition in the
p roposed rule accounted for the varying physical a nd chemical properties of the CO2 including freep hase and wate r -dissolved CO2, as the commenter suggests. The definition in the final rule will continue to do so.

EPA is developing guidance on AoR and corrective action at GS Class VI sites to assist owners or operators and Directors in evaluating requirements and proposed AoR and corrective action plans under 146.84. The guidance describes EPA's recommended appro aches for the data to be considered in an initial AoR delineation, how to apply computational modeling to delineate the AoR, performing corrective action at GS sites, and, when appropriate, completing Ao R reevaluations. The guidance will be available on EPA's web site, at http://water .epa.gov/type/groundwater/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action; 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) Comment: Proposed Rule: (b) The owner or operator of a Class VI well must prepare, maintain, and comply with a plan to deli neate the area of review for a proposed geologic sequestration project , periodically reevaluate the delineation, and
p erform corrective action that meets the requirements of this section and is acceptable to the Director. As a part of the permit application for approval by the Director, the owner or operator must s ubmit an area of revi ew and corrective action plan that includes the following information:

Schlumberger Suggested Revision: (b) The owner or operator of a Class VI well must prepare, maintain, and comply with a plan to delineate the area of review for a proposed geologic sequestration proj ect, reevaluate the delineation, and
p erform corrective action that meets th e requirements of th is section in a manner and at a frequency acceptable to the Director. As a part of the permit application, the owner or operator must s ubmit an area of revi ew and corrective action plan that includes the following information:

Schlumberger Rationale: -

Response: EPA disagrees with the proposed changes and retains the provisions as proposed. For additional information on EPA's approach to AoR and corrective action, please see the final rule and
p reamble.

Other EPA Comment Codes and Descriptions: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) Comment: Proposed Rule: (i) The minimum fixed fre quency, not to exceed 10 years, the owner or operator proposes to reev aluate the area of review;

Schlumber g er Su gg ested Revision: Revision: (i ) The owner or operator will Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24021

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24022reevaluate the AOR after two years, 5 years and then no less frequently than every 5 years for period of injection. This schedule may be relaxed at the discretion of the director in the post injection period if appropriate data exist to support the change.

Schlumberger Rationale: We feel that a fr equency of every 10 years is too long to identify early discrepancies between th e site performance a nd the site model. Seeing early difference will allow for earlier m odel updating and provide additional reduction in leakage risk a nd a better understanding of the site.

Response: EPA agrees with commenters that reevaluati ons of the AoR every ten years may not be sufficient to appropriately model plume and pressure front movement, establish conditions for corrective action, and ensure protection of US DWs from endangerment. For these reasons, the Agency changed the minimum frequency for the AoR reevaluation at §146.84(e) from 10 years to at least every 5 years in the final GS rule. EPA believes that this revised fr equency addresses commenters' concerns about the inherent uncertainties in modeling CO2 movement, the emerging nature of GS technology, risk-based targeting of monitoring activities, and the unique nature of CO2 GS. In addition, the Director has discretion to require more frequent AoR reevaluation if he or she has reason to believe, based on sitespecific information, that a five-y ear reevaluation schedule is not sufficiently protective of USDWs.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: Proposed Rule: (iv) How corrective action will be conducted to meet the requirements of paragraph (d) of this section, including what corrective action will be performed prior to injection a nd what, if any, portions of the area of review will have corrective action addressed on a phased basis and how the
p hasing will be determined; how corrective action will be adjusted if there are changes in the area of review; and how site access will be guaranteed for future corrective action.

Schlumberger Suggested Revision: (iv) Ho w corrective action will be conducted to meet the requirements of paragraph (d) of this section, including what corrective action will be performed pr ior to injection and what, if any,
p ortions of the area of re view will have corrective action addressed on a phased basis and how the phasing will be determ ined; how corrective action will be adjusted if there are changes in the area of review; and how site access will be arranged for future corrective action.

Schlumberger Rationale: Future access cannot be fully guaranteed for an area in advance that may not even be within th e boundaries of the initial AOR/ project.

Response: EPA is retaining this requirement as pr oposed. The purpose of the corrective action requirement at §146.84(d) is to ensure that all wells in the AoR that have the potential to cause the movement of CO2 or other fluids into or betw een USDWs receive appropriate corrective action. In general, to meet this re quirement, the owner or operator will most likely need to obtain the right of access to wells that may re quire corrective action, and demonstrate they have done this in their proposed AoR and corrective action plan. In the AoR and co rrective action plan, the owner or operator must describe how site access will be guaranteed for future corrective action. §146.84(b)(2)(iv). Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24023Other EPA Comment Codes and Descriptions: 3110 2.1.1 Proposed siting requirements (i.e., injection/confining zones, trapping mechanism) Comment: Proposed Rule: (i) Be based on detailed geologic data collected to characterize the injection zone, confining zone and any additional zones; and anticipated operating data, including injection pressures, rates and total volumes over the
p roposed life of the geolog ical sequestration project;

Schlumberger Suggested Revision: (i) Be based on detailed geologic data collected to characterize the injection zone, confining zone(s), monitoring zones and any additional zones; and anticipated operating data, including injection pressures, rates and total vol umes over the proposed life of the geological sequestration project;

Schlumberger Rationale: We feel that if there are second ary confining units that they should be included in the site m odel along with any tr ansmissive zones between the primary and s econdary confining units.

Response: EPA agrees that all geologic data about the si te, including confining z one(s) and transmissive zones, should be addressed in the model but disagr ees that the suggested revision is necessary. EPA clarifies that the AoR delineation model must be based on detailed geologic data collected to characterize the injection zone, confining zone and any additional z ones (§146.84(c)(1)(i)).

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action; 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Proposed Rule: (3) Determine which abandone d wells in the area of review have been plugged (as required by §146.92) in a manne r that prevents the movement of carbon dioxide or associated flui ds that may endanger USDWs.

Schlumberger Suggested Revision: (3) Determine which abandoned wells identified in 146.84 (c) (2) have been plugged (a s required by §146.92) in a manner that
p revents the movement of carbon dioxide or formation fluids that may endanger USDWs.

Schlumberger Rationale: -

Response: EPA acknowledges the comment. Based on its evaluation of al l public comments and input on the proposed rule and NODA and Request for Co mment, EPA has made many revisions to the GS Rule. See the final rule and preamble for fu rther discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: Proposed Rule: (d) Owners or operators of Class VI wells must perform corrective action on all wells in the area of review that are determined to need corrective action usin g methods necessar y to prevent the movement of fluid into or between Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24025

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24027

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24028USDWs including use of corrosion resistant materials, where appropriate.

Schlumberger Suggested Revision: Owners or operators of Class VI wells must
p erform corrective action using corrosion resistant materials, when appropriate, on all wells identified in 146.84(c)(2) that are determined to need corrective action".

Schlumberger Rationale: -

Response: EPA revised the text at §146.84(d) to require the use of materials that are "compatible with the carbon dioxide stream" Instead of corrosion resistant materials. EP A believes this language change addresses commenters' concerns and is also consistent with other langua ge regarding materials requirements in the GS rule. EPA did not make the other suggested changes. See the final rule and
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) Comment: Proposed Rule: (f) At the minimum fixed frequency, not to exceed 10 years, as specified in the area of review and corr ective action plan, or when monitoring and operational conditions warrant, owners or operators must:

Schlumberger Suggested Revision: (f) At the same frequency as the reevaluation of the AOR as specified in 146.84(c ) (2) (i), or when monitoring and operational conditions warrant, owners or operators must:

Schlumberger Rationale: -

Response: EPA disagrees with the proposed changes and retains the provisions as proposed. EPA believes that the commenter’s suggested edit has s ubstantively the same meaning as the proposed text. For additional information on EPA's approach to AoR and corrective action, please see the final rule and
p reamble.

Other EPA Comment Codes and Descriptions: 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Proposed Rule: (4) Submit an amended area of review and corrective action plan or demonstrate to the Director through monitoring data and modeling results that no amendment to the area of review a nd corrective action plan is needed.

Schlumberger Suggested Revision: (4) Subm it an amended area of review and corrective action plan or demonstrate to the Director through monitoring data and modeling results that no change to th e area of review and corrective action
p lan is needed.

Schlumberger Rationale: - Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24029

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24030Response: EPA disagrees with the suggested change and believes the proposed text is clear as written. For additional information on EPA's approach to AoR and corrective action, please see the final rule and
p reamble.

Other EPA Comment Codes and Descriptions: 5400 2.9 Proposed Financial Responsibility and Long-Term Care Requirements Comment: §146.85 Financial responsibility.

Proposed Rule: (b) The owner or operator must provide to the Director, at a frequency determined by the Director, written updates of adjustments to the cost estimate to account for any amendments to the area of review and corrective action plan (§146.84), the injection well plugging plan (§146.92), and the postinjection site care and si te closure plan (§146.93).

Schlumberger Suggested Revision: (b) The owner or operator must provide to the Director, at the same frequency as th e AOR reevaluation, written updates of adjustments to the cost estimate to account for any amendments to the area of review and corrective action plan (§146.84), the injection well plugging plan (§146.92), and the post-injection site care and site closur e plan (§146.93).

Schlumberger Rationale: We feel that poten tial changes in the size of the AOR require that all site plans be reevaluate d at the same frequency as the AOR.

Response: EPA agrees that it is important to periodical ly update cost estimate s that support financial responsibility determinations. The final GS rule, at §146.85(c), requires the owner or operator to provide annual updates to the cost estimate to account for any amendments to the AoR and corrective action
p lan, the injection well plugging plan, the PISC and site closure plan, and the emergency and remedial response plan. Owners or operators must also ad just the estimates for inflation annually under §146.85 (c)(2). EPA adds that the Di rector can also require the owner or ope rator to provide an adjustment of the cost estimate if the Director de termines that the original demons tration is no longer adequate, as specified at §146.85(e). See the final rule and preamble for further discussion of EPA's final approach to financial responsibility.

Other EPA Comment Codes and Descriptions: 3800 2.3 Proposed Injection Well Construction Requirements ( 40 CFR 146.86) Comment: §146.86 Injection well constr uction requirements.

Proposed Rule: (1) Prevent the movement of fluids into or between USDWs or into any unauthorized zones;

Schlumberger Suggested Revision:(1) Preven t the movement of fluids into or between USDWs or into any unauthorized zones that causes endangerment;

Schlumberger Rationale: - Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24031

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24032Response: EPA disagrees with the suggested edit. EPA believes that protection of USDWs from endangerment and prevention of fluid movement between formations is paramount, and believes that the language as proposed meets the standards in SDWA §1421. Appropriately de signed and constructed wells are necessary to prevent endangerment to US DWs and maintain integrity of the well throughoutthe lifetime of a GS project. This is the foundation of the requirements for construction and preoperational testing of Class VI wells at §§146.86 and 146.87.

Other EPA Comment Codes and Descriptions: 3820 2.3.1 Well construction procedures Comment: Proposed Rule: (ii) Injection pressure, exte rnal pressure, internal pressure and axial loading;

Schlumberger Suggested Revision: (ii) In jection pressure, external pressure, internal pressure and axial loading;

Schlumberger Rationale: What is meant by external and internal pressure?

Response: The internal and external pressure mentione d in §146.86(b)(1)(ii) refers to pressure on the well casing. Internal pressures could be caused by cement or annular fluids; external pressures could be caused by cementing against the borehole or pressure head from formations. See the discussion of Class VI well construction requirements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guida nce on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa .gov/type/groundwater/uic/wel ls_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3800 2.3 Proposed Injection Well Construction Requirements ( 40 CFR 146.86) Comment: Proposed Rule: (vi) Down-hole temperatures;

Schlumberger Suggested Revision: (vi) Do wn-hole temperatures and pressures;

Schlumberger Rationale: -

Response: EPA believes the requirement at 146.86(b)(1)(ii), which requires consideration of Injection
p ressure, external pressure, internal pressure, and axial loading addre sses this concern, and therefore the
p roposed change is unnecessary.

Other EPA Comment Codes and Descriptions: 3822 2.3.1.1 Depth of surface casing (seeking comment); 3824 2.3.1.2 Cementing of long-s tring casing (seeking comment) Comment: Proposed Rule: (2) Surface casing must extend through the base of the lowermost USDW and be cemented to the surface.

Schlumberger Suggested Revision: (2) Su rface casing must exte nd through the base of the lowermost USDW above the in j ection zone and be cemented to the surface. Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24034

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24035

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24036Schlumberger Rationale: In some parts of th e US the USDW is very deep and this standard may preclude geologic sequestration in these areas.

Response: EPA disagrees with the suggested edit or that the surface casing requirements in the GS rule
p reclude injection below deep USDWs. The final GS rule at §146.86(b)(2) requires that surface casing extend through the base of the lowermost USDW and be cemented to the surf ace through the use of a single or multiple strings of cas ing and cement. It does not, however, specify how cementing must be accomplished, and gives flexibility to the owner or operator to propose alternate methods- to provide a sufficient amount of cement to meet the standard that USDWs are protected from endangerment. EPA notes that there are many potential ways to meet the requirement, such as the use of staged cementing.

EPA recognizes concerns re garding construction of Class VI well s where the lowermost USDW is very deep. To further address comments on deep inje ction wells, the final GS rule at §146.95 includes requirements for owners or operators that seek a waiv er of the injection depth requirements. Owners or operators of wells operating under in jection depth waivers must comp ly with additional construction requirements to ensure that wells used to inject above or between USDWs are protective. See the discussion of the waiver approach in the preamble to the final GS rule for additional information.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: Proposed Rule: (3) At least one long stri ng casing, using a sufficient number of centralizers, must extend to the inj ection zone and must be cemented by circulating cement to the surf ace in one or more stages.

Schlumberger Suggested Revision: -

Schlumberger Rationale: We support this language work by Carey et al and crow et al shows that CO2 can move above the top of the CO2 reservoir, so cementing to surface will provide the best chance to have maximum zonal isolation

Response: EPA agrees that the requirement for long-string casing of Class VI well s at §146.86(b) will offer the best protection against fluid movement behind the casing, be tween formations, and above the injection zone and will ensure competency of Cl ass VI wells and protect USDWs from endangerment. The buoyant nature of CO2 dictates deep well constr uction procedures that address movement of fluid behind the casing and provide necessa ry barriers to CO2 leakage outside of the injection zone. In developing the construction requirements for Class VI wells, EPA reviewed the work cited by Carey et al. (2007) and Crow et al. (2008). EPA agrees th at they offer important justification for the establishment of tailored requirements.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements (seeking comment) Comment: Proposed Rule: (5) Cement and cement addi tives must be compatible with the carbon dioxide stream and formation fluids and of sufficient quality and quantit y to maintain inte g rit y over the desi g n life the g eolo g ic sequestration Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24037

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24038p roject. The integrity and location of the cement shall be verified using technology capable of evaluating cement quality radially and identifying the location of channels to ensure that USDWs are not

Schlumberger Suggested Revision: (5) Ce ment and cement additives must be suitable for use with the carbon dioxide stream and formation fluids and of sufficient quality and quantity to mainta in integrity over the project life. The integrity and location of the cement shal l be verified using technology capable of evaluating cement quality radially and identifying the location of channels to ensure that USDW s are not endangered.

Schlumberger Rationale: Well cements need to site and condition specific. There may be instances or places in the well th at will require special cements. It is also that the cement in the well last as long as the project and post injection
p eriod.

Response: EPA recognizes that each GS pr oject will be unique and, for this reason, the rule provides flexibility regarding the selection a nd use of cements for Class VI wells that are appropriate to the sitespecific conditions of the project. With the permit appli cation, the owner or opera tor must submit well construction procedures, as specif ied at §146.82 (a)(12), that demonstrat e that the well as constructed will prevent unacceptable fluid move ment; allow the use of appropriate testing devices and workover tools; and allow continuous monitoring of the annul us space between the injection tubing and longstring casing, as specified at §146.86(a) . The Director will evaluate th e procedures in the context of geological and proposed operating data about the site. EPA adds that the rule does not specify cements to be used; rather, it provides owne rs or operators with the flexibilit y to choose, as long as the cements are compatible with the CO2 stream and formation fluids and of su fficient quality and quantity to maintain integrity over the design life of th e GS project, as specified at §146.86(b)(5).

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: §146.87 Logging, sampling, and testing prior to injection well operation.

Proposed Rule: (a) During the drilling and construction of a Class VI injection well, the owner or operator must run appropriate logs, surveys and tests to determine or verify the depth, thickne ss, porosity, permeability, and lithology of, and the salinity of any formati on fluids in, all re levant geologic formations to assure conformance w ith the injection well construction requirements under §146.86, and to establish accurate baseline data against which future measurements may be compare d. The owner or operator must submit to the Director a descriptive report prepared by a knowledgeable log analyst that includes an interpretation of the results of such logs and tests. At a minimum, such logs and tests must include: Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24039Schlumberger Suggested Revision: (a) Du ring the drilling and construction of a Class VI injection well, the owner or operator must run appropriate logs, surveys and tests to determine or ve rify the depth, thickness, porosity,
p ermeability, and lithology of, and the salinity of any fo rmation fluids in, all relevant geologic formations to assure conformance with the injection well construction requirements under §146.86, and to establish accurate baseline data against which future measurements may be compared. The owner or operator must submit to the Director a descriptive report prepar ed by a knowledgeable log analyst that includes an interpretation of the results of such logs and tests. The Director may require such logs and te sts as may be needed after taking into account the availability of similar data in the area of the drilling site to ensure that the data is equivalent to the data as would be collected based on such logs and tests as::

Schlumberger Rationale: In well defined areas, these evaluations are frequently unnecessary. The director should have di scretion to select the appropriate requirements necessary to ensu re that sufficient baseli ne data and information are available. For example, in an ar ea where a number of wells are being drilled, the logging of surface hole yi elds little useful additional information.

Response: EPA disagrees that the require ments for logs, surveys, and tests are unnecessary. All logs, surveys, and tests listed at §146.87(a) are necessary to verify information about the injection and confining zones and ensure that the well is being drilled and cased as approved, and has mechanical integrity. This information is needed to demonstrate that the well can be operated and tested in a manner that protects USDWs from endange rment. While the tests do provide information on some of the same items, each test provides unique pieces of information that build on each other and allow for interpretations not possible with a single test.

EPA notes that the Director has the discretion at §146.87(a)(5) to a pprove alternative methods that
p rovide equivalent or better info rmation. EPA believes that logs a nd tests must be performed on each well drilled regardless of existi ng information about the area to account for the complexity of CO2 injection well construction and the buoyancy of CO2. Existing litholog ic and geologic information may lack the details needed for site-s pecific well design and the geology needed to support protection of USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Proposed Rule: (ii) A cement bond and vari able density log, and a temperature log after the casing is set and cemented.

Schlumberger Suggested Revision: (ii) Cement evaluation l ogs after the casing is set and cemented to evaluate cement quali ty radially with sufficient resolution to identify channels or ch anges to the cement quality.

Schlumberger Rationale: Radial is key to finding pathways but the resolution must be sufficient to see the pathways. S ee the pathway identified in Crow et al Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24040Response: EPA agrees with the suggested change. In the final GS rule, §146.87(a)(2)(ii) reads as follows: "A cement bond and variable density log to ev aluate cement quality ra dially, and a temperature log after the casing is set and cemented."

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Proposed Rule: (4) A series of tests desi gned to demonstrate the internal and external mechanical integrity of in jection wells, which may include:

Schlumberger Suggested Revision: (4) Test(s) designed to demonstrate the internal and external mechanical inte grity of injection wells, which may include:

Schlumberger Rationale: -

Response: EPA disagrees that the suggested edit is nece ssary, and the final rule retains the text as
p roposed.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Proposed Rule: (ii) A tracer survey such as oxygen-activation logging;

Schlumberger Suggested Revision: (ii) Diagnostic tools such as oxygenactivation logging;

Schlumberger Rationale: Technical correction

Response: EPA disagrees that the allowing the use of uns pecified "diagnostic tools" would provide the same amount of information as the requirement to pe rform a tracer survey. The track record for tracer surveys in evaluating mechanical inte grity has been proven over time. The Agency clarifies that a tracer survey is one of the mechanical integrity tests that may be required by the Director or used by the owner or operator.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Proposed Rule: (b) The owner or operator must take and submit to the Director whole cores or sidewall cores of the in jection zone and confining system and formation fluid samples from the inject ion zone(s). The Director may accept cores from nearby wells if the owner or operator can demonstrate that core retrieval is not possible and that such cores are representative of conditions at the well. The Director may require the owner or operator to core other formations in the borehole. Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24041

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24042

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24044Schlumberger Suggested Revision: (b) The owner or operator must submit to the Director a report describing whole cores or sidewall cores representative of the injection zone and confin ing system and formation fluid samples from the injection zone(s). The Dire ctor may accept data from cores and fluid samples from nearby wells if the owne r or operator can demonstr ate that such data are representative of condi tions at the well.

Schlumberger Rationale: The informati on required should be sufficient to
p roperly describe the injection and confining zones.

Response: EPA clarifies that it is not the Agency's in tent that physical core s be submitted to the Director. In the final GS rule, EPA has revised the first sentence of §146.87(b) to read as follows: "The owner or operator must take whole cores or sidewall cores of the in jection zone and confining system and formation fluid samples from the injection zone(s), and must submit to the Director a detailed report
p repared by a log analyst that includes: well log an alyses (including well logs), core analyses, and formation fluid sample information...."

EPA clarifies that §146.87(b) allows information on core s from nearby wells to be submitted only if the operator can demonstrate that core retrieval is not possible and that co res from nearby wells are representative of condi tions at the Class VI well. If the Direct or approves the use of alternate cores and determines that additional logs, such as video logs , are necessary to evalua te the site, he/she has authority under §146.87(a)(5) to requi re additional information.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Proposed Rule: (c) The owner or operator mu st record the fluid temperature, pH, conductivity, reservoi r pressure and the static fluid level of the injection zone(s).

Schlumberger Suggested Revision: (c) Pr ior to injection well operation, the owner or operator must record the formati on temperature, formation fluid pH and conductivity, and reser voir pressure of the injection zone(s).

Schlumberger Rationale: -

Response: EPA clarifies that all logging, sampling and testi ng for characteristics of the injection zone required in §146.87 are, as defined in the title to that section, to be performed prior to injection well operation. EPA adds that §146.82(c)(7) requires that the Director evaluate the re sults of all logging and testing prior to authorizing injection.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Proposed Rule:(f) The owner or operator must provide the Director with the opportunit y to witness all lo gg in g and testin g b y this subpart. The owner or Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24045

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24047operator must submit a schedule of such ac tivities to the Dire ctor 30 days prior to conducting the first test and submit any changes to the schedule 30 days
p rior to the next scheduled test.

Schlumberger Suggested Revision: (f) Th e owner or operator must provide the Director with the opportunity to witn ess all logging and testing by this subpart. The owner or operator must submit a schedule of such activities to the Director upon spudding the well and submit any changes to the schedule 48 hours
p rior to the scheduled test.

Schlumberger Rationale: The changes refl ect the realities of flexible rig schedules and consistency with Class II practices.

Response: EPA disagrees that the 30-day notificati on requirement is unreasonable. The 30-day notification mirrors the current requirement for logging and testing of new Class I wells, as described in §146.66. Acknowledging the developing nature of CO2 GS, EPA believes that involvement by the
p ermitting authority in each projec t will provide much needed field data for assurance of USDW
p rotection from endangerment and will help update a nd refine the permitting pr ocess. Adequate timing of notification will ensure the Director's ability to be involved.

Other EPA Comment Codes and Descriptions: 4110 2.4.1.1 Injection pressure limitations Comment: §146.88 Injection well opera ting requirements.

Proposed Rule: (a) Except dur ing stimulation, the owner or operator must ensure that injection pressure does not exceed 90 percent of the fracture pressure of the injection zone so as to assure th at the injection does not initiate new fractures or propagate exis ting fractures in the injection zone. In no case may injection pressure initiate fractures in the confining zone(s) or cause the movement of injection or formation fluids that e ndangers a USDW.

Schlumberger Suggested Revision: (a) Except during stimulation, the owner or operator must ensure that injection pres sure does not exceed 90 percent of the hydraulic fracture pressure of the confining zone so as to assure that the injection does not initiate new fractures or propagate existing fractures in the confining zone. In no case may injection pressure initiate fractures in the confining zone(s) or cause the movement of injection or formation fluids that endangers a USDW.

Schlumberger Rationale: Maintaining the in tegrity of the confining zone is the critical parameter.

Response: EPA agrees that maintaining the integrity of the confining zone is criti cal in order to protect USDWs from endangerment. However, EPA also believ es that the injection pressure should not exceed 90 percent of the fracture pressure of the injection zone. The final rule retains this provision at §146.88 (a). EPA believes that the 90 percent requirement , which was suggested by IO GCC and permit writers whom EPA consulted when writing the regulation, is a satisfactory margin of safety for well operation. Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24048Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Proposed Rule: (e) Upon completion, but prior to operation, the owner or operator must conduct the followi ng tests to verify hydrogeologic characteristics of the injection zone:

Schlumberger Suggested Revision: (d) At any time prior to injection well operation, the owner or operator must de termine fracture pr essures of the injection and confining zones and conduc t tests to verify hydrogeologic and geomechanical characteristics of the injection zone, e.g.:

Schlumberger Rationale: -

Response: EPA disagrees that the suggested edit is nece ssary, and the final rule retains the text as
p roposed.

Other EPA Comment Codes and Descriptions: 4000 2.4 Proposed Injection Well Operating Requirements ( 40 CFR 146.88) Comment: Proposed Rule: (b) Injection between the outermost casing protecting USDWs and the well bore is prohibited.

Schlumberger Suggested Revision: (b) Inj ection of the CO2 stream between the outermost casing protecting USDWs a nd the well bore is prohibited.

Schlumberger Rationale: -

Response: EPA retains the provision as propos ed, and clarifies that injection between the casing and the well bore is prohibited. This is cons istent with requirements for other injection well classes in the UIC
p rogram.

Other EPA Comment Codes and Descriptions: 4000 2.4 Proposed Injection Well Operating Requirements ( 40 CFR 146.88) Comment: Proposed Rule: (c) The owner or operator must fill the annulus between the tubing and the long string casing with a non-corrosive fluid approved by the Director. The owner or operator must maintain on the annulus a pressure that exceeds the operating injection pressure, unless the Director determines that such requirement might harm the integrity of the well.

Schlumberger Suggested Revision: (c) The owner or operator must fill the annulus between the tubing and the long stri ng casing with a non-corrosive fluid approved by the Director.

Schlumber g er Rationale: Industr y experience with the Class II UIC pro g ram does Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24049

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24050

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24051not support this requirement.

Response: EPA believes that maintaining an annulus pressure that is highe r than the injection pressure, as required at §146.88(c), will ensure that if there are leaks in the tubing, the annulus fluid will move into the tubing, rather than the inj ectate moving out of the tubing and potentially along the outside of the well. EPA believes this requirement is appropriate and necessary for Class VI wells given the potential high volumes and supercritical nature of the CO2 in jectate, potential geomechanical stresses in the wellbore, and the potential for movement of the CO 2 in the event of a mechanical integrity loss.

Other EPA Comment Codes and Descriptions: 4000 2.4 Proposed Injection Well Operating Requirements ( 40 CFR 146.88) Comment: Proposed Rule: (3) Notify the Director within 24 hours

Schlumberger Suggested Revision: (3) Noti fy the Director within 24 hours of discovery;

Schlumberger Rationale: -

Response: The final rule text at §146.88(f) now reads, "I f a shutdown (i.e., down-hole or at the surface) is triggered or a loss of mechanical integrity is discovered." Therefore the notice required at §146.88(f) (3) must be provided within 24 hours of an automati c shut-off device being triggered or a loss of mechanical integrity being discovered. EPA believes this provision is necessary to ensure timely response to potential USDW endangerment.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: §146.90 Testing and monitoring requirements.

Proposed Rule: (b) Installation and use, except during well workovers as defined in §146.86(d), of continuous recording devices to monitor injection pressure, rate and volume; the pressure on the a nnulus between the tubing and the long string casing; and the annulus fluid volume;

Schlumberger Suggested Revision: -

Schlumberger Rationale: 146.86(d) does not exist; perhaps 146.88(d) is what was intended.

Response: EPA acknowledges the comment; the final ru le contains the suggested revision.

Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: Proposed Rule: (c) Corrosion monitorin g of the well materials for loss of mass, Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24052

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24053

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24054thickness, cracking, pitting a nd other signs of corrosion must be performed on a quarterly basis to ensure that the well components meet the minimum standards for material strength and perfor mance set forth in §146.86(b) by:

Schlumberger Suggested Revision: (c) Corrosion monitoring of the well materials for loss of mass, thickness, cracking, pitt ing and other signs of corrosion must be performed quarterly and may be modifi ed to be less frequent as approved by the Director based on c onstruction materials, operating conditions, and monitoring history to ensure that the well components meet the minimum standards for material strength and perfor mance set forth in §146.86(b) by:

Schlumberger Rationale: Allows applicat ion of performance based approach.

Response: EPA believes that corrosion monitoring is appr opriate given the potentially corrosive nature of the CO2 stream. CO2 in the presence of water becomes acidic, potentially accelerating corrosion of well materials. The CO2 stream for a GS project may also contain small vol umes of impurities that could contribute to corrosion. For these reasons, the final rule requires quarterly corrosion monitoring at §146.90(c), as proposed.

Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: Proposed Rule: (1) Placing coupons of the well construction mate rials in contact with the carbon dioxide stream; or

Schlumberger Suggested Revision: (1) Anal yzing coupons of the well construction materials placed in contact with the carbon dioxide stream; or

Schlumberger Rationale: -

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has ma de many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: Proposed Rule: (2) Routing the carbon dioxide stream through a loop constructed with the material used in the well; or

Schlumberger Suggested Revision: (2) Rout ing the carbon dioxide stream through a loop constructed with the material used in the well and inspecting the materials in the loop; or

Schlumberger Rationale: -

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has ma de many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach. Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24055

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24056Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: Proposed Rule: (3) Using an alternat ive method approved by the Director;

Schlumberger Suggested Revision: (3) Using an alternative method, materials, or time period approved by the Director;

Schlumberger Rationale: -

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has ma de many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4660 2.6.6 Geochemical monitoring Comment: Proposed Rule: (d) Periodic monitori ng of the ground water quality and geochemical changes above the confining z one(s) that may be a result of carbon dioxide movement through the confining z one or additional identified zones:

Schlumberger Suggested Revision: (d) Periodic monitoring of the ground water quality for geochemical changes above the c onfining zone(s) that may be a result of carbon dioxide movement through the conf ining zone or additional identified

zones:

Schlumberger Rationale: -

Response: EPA did not make the suggested change. Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4650 2.6.5 CO2 plume and pressure front tracking (seeking comment) Comment: Proposed Rule: (1) The location and number of monitoring wells must be based on specific information about the geologic sequestration project, including injection rate and volume, geology, the presence of artificial penetrations and other factors;

Schlumberger Suggested Revision: (1) The location and number of monitoring wells must be based on specific information about the geologic sequestration project, including injection rate and volume, geology, the presence of artificial
p enetrations and other relevant factors as warranted by a ris k -assessment;

Schlumber g er Rationale: The monitorin g should be desi g ned to reduce risk Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24057

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumberger Carbon Services Comment ID: 24058

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24059Response: EPA agrees that monitoring plans and methods need to be site-specific and believes that the monitoring requirements for GS sites at §146.90 provide an appropriate level of fl exibility in structuring a testing and monitoring plan that protects USDWs from endangerment. EPA retains the requirement regarding placement of monitoring we lls, but adds that any additional relevant site-specific information must be considered in the development of the test ing and monitoring plan to ensure USDW protection from endangerment.

EPA is developing guidance on testing and monitoring to assist owners or opera tors and Directors in evaluating requirements under §146.90, in cluding proposed monitoring pl ans. The guidance describes available technologies and recommended approaches for implementing a test ing and monitoring plan, including pre-operational geophys ical logging and test ing of injection wells, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4660 2.6.6 Geochemical monitoring Comment: Proposed Rule: (2) The monitoring fre quency and spatial distribution of monitoring wells must be based on baseli ne geochemical data that has been collected under §146.82(a) (6) and any modeli ng results in the area of review evaluation required by §146.84(b);

Schlumberger Suggested Revision: (2) The monitoring frequency and spatial distribution of monitoring wells must be based on geological and geophysical data that has been collected under §146.82( d) and any modeling results in the area of review evaluati on required by §146.84(b);

Schlumberger Rationale:Geochemical data does not seem have a high degree of relevance in selecting m onitoring well sites.

Response: EPA believes that baseline characterization of the site, incl uding the geochemical data and initial modeling, will be highly valu able in selection of monitoring we ll locations and in refining plans for monitoring frequency. The GS rule stipulates that the monitoring frequency and spatial distribution of monitoring wells must be based on baseline geochemical data that were collected during the initial site characterization and the area of review evaluation at §146.90(d)(2). The details of the geochemical monitoring will be based on site-speci fic information and described in the Director-approved testing and monitoring plan.

Other EPA Comment Codes and Descriptions: 4546 2.5.2.2 MIT frequency (seeking comment) Comment: Proposed Rule: (e) A demonstration of extern al mechanical integr ity pursuant to §146.89(c) at least once per year throug hout the duration of the geologic sequestration project;

Schlumber g er Su gg ested Revision: (e) A demonstration of external mechanical Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24060

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24061integrity pursuant to §146.89(c) at least once per year throughout the life of the well;

Schlumberger Rationale: -

Response: EPA is retaining the language as proposed. EPA cl arifies that the monitoring and testing plan requirements in §146.90 cover the peri od prior to well plugging. External MITs are not required once a well is plugged, as this test woul d no longer be possible in a plugged we ll. If a well is plugged prior to site closure, no further MITs are required for that well.

Other EPA Comment Codes and Descriptions: 4640 2.6.4 Pressure fall-off testing (seeking comment)

Comment: Proposed Rule: (f) A pressure fall-off te st at least once every five years unless more frequent testing is required by the Director based on site specific information;

Schlumberger Suggested Revision: (f) A pressure fall-off test or other equivalent test that identifies reser voir conditions with respect to flow dynamics at least once every five years unl ess more frequent testing is required by the Director based on site specific information;

Schlumberger Rationale: Allows more flex ibility while still providing the needed information

Response: EPA believes that pressure fall -off testing is necessary for GS wells. Pressure fall-off tests are designed to verify that modeled projections of reservoir pressure decl ine agree with measured
p ressure decline profiles. These tests can be useful in AoR calculations and reevaluations and may also indicate mischaracter ization of site geology and the presen ce of leakage pathways. EPA therefore believes that pressure fall-off testing is conducte d at least once every five years and the final GS regulation includes this requirement at §146.90(f). Pressure fall-off test s may be conducted in conjunction with other well performance tests (i.e., me chanical integrity testing) to ensure safe and effective operations.

Other EPA Comment Codes and Descriptions: 4650 2.6.5 CO2 plume and pressure front tracking (seeking comment) Comment: Proposed Rule: (g) Testing and monitoring to track the extent of the carbon dioxide plume and the position of the pre ssure front by either monitoring for
p ressure changes in the first formation overlying the confining zone or using indirect, geophysical tec hniques (e.g., seismic, electrical, gravity, or electromagnetic surveys and/or down-hol e carbon dioxide detection tools);

Schlumberger Suggested Revision: (g) Test ing and monitoring to track the extent of the carbon dioxide plume and the position of the pressure front.

Schlumber g er Rationale:Monitorin g outside of the in j ection zone provi des little Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24062

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24063information of value for trac king and monitoring the inject ed plume. Examples of how to test and monitor could be included in the Preamble.

Response: As described above, EPA has revised this re quirement in the final rule. The final GS regulation, at §146.90(g)(1), requi res all GS project owners or operators to monitor directly for pressure changes in the injection zone. EPA believes that pre ssure monitoring in the inj ection zone is necessary to track the development and move ment of the pressure front and CO2 plume. In addition, §146.90(g)(2) requires owners or operators to track the positi on of the CO2 plume usi ng indirect methods (e.g., seismic, electrical, gravity, or el ectromagnetic surveys and/or down-hole CO2 detection tools), unless the Director determines based on site-specific geology, that such methods are not appropriate.

Other EPA Comment Codes and Descriptions: 4670 2.6.7 Surface air monitoring and/or soil gas monitoring (seeking comment) Comment: Proposed Rule: (h) At the Director’s di scretion, surface air monitoring and/or soil gas monitoring to detect movement of carbon dioxide that could endanger a USDW.

Schlumberger Suggested Revision: (h) At the Director’s discretion based on sitespecific conditions and risk- based factor s, surface air monitoring and/or soil gas monitoring to detect m ovement of carbon dioxide th at could endanger a USDW.

Schlumberger Rationale: In most situat ions soil and air monitoring does not
p rovide an effective method of protecting USDWs.

Response: EPA acknowledges that air and soil gas monitoring to ensure USDW protection is not necessary at all GS sites and agrees that the deci sion to use surface monitoring and th e selection of monitoring methods for the purpose of USDW protection will be site-specific.

In the final rule, at §146.90(h), the decision to requi re such monitoring as an additional measure to ensure USDW protection rests with th e Director as a means of identify ing leaks that may pose a risk to USDWs and informing emergency notif ication of a Class VI owner or operator and UIC Director in the event of a USDW endangerment, pursuant to requirements at §146.91(c).

The Agency believes that surface air and soil gas monitoring, when coupled with subsurface monitoring, may be appropriate at some GS projects to en sure USDW protection. EPA also acknowledges that surface air and soil gas measurements are subject to va riability and may not be suitable in all settings as a method to ensure USDW protection. However, EPA doe s not believe that this should entirely preclude their use. The decision to use surf ace monitoring and the se lection of monitoring me thods will be sitespecific (e.g., may be influenced by geology, inject ion depth, and operational conditions) and must be based on potential risks to USDWs within the AoR.

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Proposed Rule: (1) The testing and monitori ng plan must be based on potential vulnerabilities within the area of review; Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24064

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24065Schlumberger Suggested Revision: (1) The testing and monitoring plan must be based on site-specific geologic factors, modeling, and risk-ass essment within the area of review;

Schlumberger Rationale: -

Response: EPA anticipates that the testing and monitori ng plan will address site-specific geologic factors, modeling, and risk -assessment. EPA is developing guidance on how best to develop the various required project plans, including the testing and monitoring plan. The guida nce can be found on EPA’s website at http://water.epa.gov/type/g roundwater/uic/wells _sequestration.cfm.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: §146.91 Reporting requirements.

Proposed Rule: (1) Any changes to the phys ical, chemical and other relevant characteristics of the carbon dioxide stream from the proposed operating data;

Schlumberger Suggested Revision: (1) A ny significant changes to the physical, chemical and other relevant characteristi cs of the carbon dioxide stream from the proposed operating data;

Schlumberger Rationale: Minor changes could just be due to uncertainty in measurements or models

Response: EPA retained this provision as proposed. The final rule at §146.91(a)(3) requires reporting of all exceedances of operating parameters. EPA disagr ees with the suggestion to report only "significant" exceedances. Making a determination as to whether an exceedance is "significant" is not the purpose of the requirement. EPA believes that the ability of an operator to consistently meet operating requirements and avoid exceedances provides evidence of a well-man aged GS project that is in compliance with the Class VI permit. If multiple exceedances occur, the Director should be aware of such occurrences and determine whether these indicate non-compliance at the site, and require the appr opriate course of action (e.g., a well workover, modi fication of operating parameters, or im position of a penalty). Please see the final rule and the discussion of testing and monitoring in the preamble for additional information.

EPA clarifies that the rule, at §146.91(c), also require s operators to notify the Director, within 24 hours, of any event that may cau se endangerment to a USDW. If such ev ents occur outside of business hours (e.g., over night), operators must re port to the Director within 24 hours, and permitting agencies have staff and procedures to respond to these types of calls 24 hours a day, 7 days a week. Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24066

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24067Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: §146.92 Injection well plugging.

Proposed Rule: (a) Prior to the well pl ugging, the owner or ope rator must flush each Class VI injection well with a buffer fluid, determine bottomhole reservoir
p ressure, and perform a final me chanical integrity test.

Schlumberger Suggested Revision: (a) Pr ior to the well plugging, the owner or operator must flush each Class VI inject ion well with a buffer fluid, determine bottomhole reservoir pressure , and perform a final extern al mechanical integrity
test.

Schlumberger Rationale: Many of the components that would be tested by an internal MIT are removed or test ed during the plugging process.

Response: EPA agrees that only an external MIT is re quired, and has modified the GS rule at §146.92 (a) to require owners or operators to perform a final external mechanical integrity test prior to the well
p lugging.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Proposed Rule: (2) Appropriate testing methods to ensure mechanical integrity as specified in §146.89;

Schlumberger Suggested Revision: (2) Appropr iate testing methods to ensure final external mechanical integrity as specified in §146.89(c);

Schlumberger Rationale: Many of the components that would be tested by an internal MIT are removed or test ed during the plugging process.

Response: EPA agrees that only an external MIT is re quired, and has modified the GS rule at §146.92 (a) to require owners or operators to perform a final external mechanical integrity test prior to the well
p lugging.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Proposed Rule: (5) The type and grade and quantity of material to be used in
p lugging. The material must be compatible with the carbon di oxide stream; and

Schlumberger Suggested Revision: (5) The t ype and grade and quantity of material to be used in plugging. The material must be suitable for use with the carbon dioxide stream; and

Schlumber g er Rationale: - Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24068

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24069Response: EPA believes, considering the pote ntially corrosive nature of CO2 when it is in contact with water, that the requirement that the material must be compatible with the CO2 stream is appropriate. The final rule retains this requirement.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Proposed Rule: (d) Plugging report. Within 60 days after plugging or at the time of the next semi-annual report (whichever occurs earlier) the owner or operator must submit a plugging report to the Direct or. If the semi-annual report is due less than 15 days after completion of plugging, then the report must be submitted within 60 days after pluggi ng. The report must be certified as accurate by the owner or op erator and by the person who performed the plugging operation (if other than the owner or operator.)

Schlumberger Suggested Revision: (d) Plugging report. Within 60 days after
p lugging the owner or operator must submit a plugging report to the Director. The report must be certifie d as accurate by the owner or operator and by the
p erson who performed the plugging operatio n (if other than the owner or operator.)

Schlumberger Rationa le: Simplification

Response: EPA has revised the text at §146.92(d) to reduce c onfusion. The final rule text reads, "Within 60 days after plugging the owner or operator must submit a pluggi ng report to the Director."

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment); 5260 2.8.2.3 Adjusting the post-injection timeframe (seeking comment) Comment: §146.93 Post-injection site care and site closure.

Proposed Rule: (1) The owner or operator sh all continue to conduct monitoring as specified in the Director-approved post-in jection site care and site closure
p lan for at least 50 years following the cessation of injection. At the Director’s discretion, the monitoring will continue until the geologic sequestration project no longer poses an endangerment to USDWs.

Schlumberger Suggested Revision: (1) The owner or operator shall continue to conduct monitoring as spec ified in the Director-appr oved post-injection site care and site closure plan, pursuant to th e performance based criteria described in 146.93(3).

Schlumberger Rationale: The 50 year default period is not based on any scientific or technical in formation and could be considered arbitrary and capricious. Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24070

Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24071Proposed Rule: (2) If the owner or operato r can demonstrate to the satisfaction of the Director before 50 years, based on monitoring and other site-specific data, that the geologic sequestration proj ect no longer poses an endangerment to USDWs, the Director may approve an amendm ent to the post-injection site care and site closure plan to reduce the frequenc y of monitoring or may authorize site closure before the end of the 50-year period.

Schlumberger Suggested Revision: (2) If the owner or operator can demonstrate to the satisfaction of the Director that the geologic sequestration project no longer poses an endangerment to USDWs, the Director may approve an amendment to the post- injection site care and site cl osure plan to reduce the frequency of monitoring or may authorize site closure.

Schlumberger Rationale: -

Response: EPA disagrees that a post-injection site care ti meframe of 50 years is excessive in most cases or is arbitrary and capricious. EPA proposed a defa ult post-injection site car e timeframe of 50 years based on a review of research st udies, industry reports, and existing environmental programs. This analysis was included in an EPA-prepared background document that is available in the federal docket, titled "Computational Modeling of Underground Injection of Carbon Dioxide for Determination of Area-of-Review and Potential Risk to Underground Sources of Drinking Water." EPA assessed various default timeframes based on additiona l review of research studies a nd evaluation of public comments. While numerous commenters suggested that EPA shorten the monitoring timeframe, none of the commenters provided sufficient data or other evidence to warrant a ch ange in the proposed timeframe. While the 10- or 30-year timeframe suggested by some of these commenters may be within the timeframe suggested in so me studies, EPA believes that the poten tial risks of endangering USDWs will likely not decline within these timeframes and av ailable data, including data submitted by commenters, do not support a different default timeframe. However, EPA recognizes that alte rnative timeframes may be appropriate under limited, specific circumstances.

For this reason, the GS rule offers owners or opera tors flexibility regarding the duration of the PISC timeframe by: (1) allowing the Direct or discretion to shorten or lengt hen the PISC timeframe during the
p ost-injection period based on site-specific data, pursuant to requi rements at §146.93(b); or (2) affording the Director discretion to allow a Class VI well ow ner or operator to demonstr ate, during the permitting
p rocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe for
p ost-injection site care will be necessary in all buta limited number of cases. This default 50 year postinjection site care timeframe repres ents a reasonable and protective m onitoring period based on a review of research studies, industry repor ts, and existing envir onmental programs, and evaluation of public
comments.

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts.EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and m onitoring wells; perform post-inject ion monitoring; demonstrate the appropriateness of an alternative pos t-injection site care time frame; demonstrate non endangerment; and
p erform site closure activities. The guidance will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Proposed Rule: (3) Prior to authorization for site closure, the owner or operator must submit to the Director a demonstration, based on monitoring and other site-specific data, that the carbon dioxide plume and pressure front have stabilized and that no additional monito ring is needed to assure that the geologic sequestration proj ect does not pose an endangerment to USDWs.

Schlumberger Suggested Revision: (3) Prio r to authorization for site closure, the owner or operator must demonstrate to the Director, based on monitoring and other site-specific data that no additional monitoring is needed to assure that the geologic sequestration project does not pose an endangerment to USDWs, considering the following:. (i) the estima ted magnitude and extent of the AOR based on measurements and modeling; (ii) th at CO2 movement and pressure changes match model predictions, (iii) the estimated location of the detectable CO2
p lume based on measurement and modeling (measuring magnitude of saturation within (iv) that there is no evidence of significant leakage of either CO2 or formation fluids that endanger USDWs; (v) that the CO2 plume and displaced formation fluid are not expected to migr ate in the future in a manner that encounters a potential leakage pathway; and, (vi) that we lls at the site are not leaking and have maintained integrity.

Schlumberger Rationale: Establishes the performance based criteria for selecting the monitoring period. the plume or mapping the edge of it);

Response: The post-injection site care requirements in the final GS rule, §146.93(b), incorporate a combination of a fixed timeframe and a performance sta ndard approach. Specifically , the GS rule offers owners or operators flexibility regarding the dur ation of the PISC timeframe by: (1) allowing the Director discretion to shorten or lengthen the PISC timeframe during the pos t-injection period based on site-specific data, pursuant to requirements at §146.93( b); or (2) affording the Director discretion to allow a Class VI well owner or operator to demonstrate, during the permitting process based on substantial data, that an alternative PISC timefram e may be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe for
p ost-injection site care will be necessary in most cases. The default 50 year post-injection site care timeframe represents a r easonable and protective monitoring peri od based on a review of research studies, industry reports, and exis ting environmental programs, and evaluation of public comments. EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS pro j ects durin g the permittin g process where substantial data Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24072exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts. EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirement s of 146.92 and 146.93. Additionally, the guidance will assist Directors in evaluating proposed well plugging plans and post-inject ion site care and site closure plans under 146.92 and 146.93. The guidance describes recommended approaches for how an owner or operatorcould plug injection and monitoring wells; demonstrate the appropriateness of an alternative postinjection site care time frame; perform post-injection monitoring; demonstrate non endangerment; and
p erform site closure activities. The guidance will be available at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Proposed Rule: (e) Once the Director has au thorized site closur e, the owner or operator must submit a site closure repor t within 90 days that must thereafter be retained at a location designated by the Director. The re port must include:

Schlumberger Suggested Revision: (e) On ce the Director has authorized site closure, the owner or operator must submit a site closure report within 90 days after completion of all closure oper ations. The report must include:

Schlumberger Rationale: What is the rete ntion period? Many other programs have a three year limit for retention of records. EPA is the steward of information at this point of the project, not the owner or operator.

Response: EPA disagrees that the owner or operator should not be responsible for record retention such as site closure reports. EPA believes that the require ments that the owner or operator retain for ten years following site closure, records collected during the post-injecti on site care period at §146.93(f) and §146.93(h) are appropriate for the post-injection and site closure period to ensure that data are available to support non-endangerment de monstrations and to address any con cerns that may arise following site closure. This data will also suppor t EPA's review of project data as part of the adaptive rulemaking approach.

Other EPA Comment Codes and Descriptions: 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Proposed Rule: (1) Documentation of appr opriate injection and monitoring well
p lugging as specified in §146.92 and paragraph (c) of this section. The owner or operator must provide a copy of a survey plat which has been submitted to the local zoning authority designated by the Di rector. The plat must indicate the location of the injection well relative to permanently surveyed benchmarks. The owner or operator must also submit a copy of the plat to the Regional Administrator of the appropr iate EPA Regional Office;

Schlumber g er Su gg ested Revision: (1) Documentation of appropriate in j ection and Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24073

Commenter Name: Andrew Dugui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24074monitoring well plugging as specified in §146.92 and paragraph (c) of this section. The owner or operator must provide a copy of a survey plat which has been submitted to the local zoning author ity designated by the Director. The
p lat must indicate the location of the inje ction well(s) relative to permanently surveyed benchmarks. The owner or operator must also submit a copy of the plat to the Regional Administrator of th e appropriate EPA Regional Office;

Schlumberger Rationale: -

Response: The GS regulation at §146.93(g) requires the owne r or operator to record a notation on the deed to the facility prope rty or other similar document examined during a title search that the land has been used to sequester CO2 on the deed to the facility property at the time of site closure.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: §146.94 Emergency and remedial response.

Proposed Rule: (b) If the owner or operato r obtains evidence that the injected carbon dioxide stream and asso ciated pressure front may cause an endangerment to a USDW, the owner or operator must:

Schlumberger Suggested Revision: (b) If the owner or operator obtains evidence that the injected carbon dioxide stream or associated pr essure front endangers a USDW, the owner or operator must:

Schlumberger Rationale: -

Proposed Rule: (2) Take all steps reas onably necessary to identify and characterize any release;

Schlumberger Suggested Revision: (2) Ta ke all steps reasonably necessary to identify and characterize the endangerment posed;

Schlumberger Rationale: -

Proposed Rule: (3) Notify the Di rector within 24 hours; and

Schlumberger Suggested Revision: (3) Noti fy the Director within 24 hours of becoming aware of the endangerment; and

Schlumberger Rationale:-

Proposed Rule: (d) The owner or operator must notify the Director and obtain his approval prior to conducting any well workover.

Schlumberger Suggested Revision: (d) Th e owner or operator must notify the Director prior to conducting any well workover in response to any case of endan g erment. Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24075Schlumberger Rationale:In critical situ ations, time spent obtaining approval could adversely affect the ability to conduct operations or increase the level of endangerment.

Response: After consideration of comments, EPA has finalized the rule language in §146.94(b) as
p roposed. In the introductory section of §146.94(b), EPA clarifies that the pressure front, as defined in §146.81, is a zone where the pressure differential is suff icient to cause the moveme nt of injected fluids or formation fluids into a USDW. Therefore, displ aced formation fluids are im plicitly included in the requirements for §146.94. EPA also clarif ies that owners or operators must take action when the CO2 stream or pressure front may caus e endangerment. In order to preven t the endangerment of USDWs, as required under §1421 of the SDWA, EPA expects the ow ner or operator to act preemptively and not wait until endangerment has occurred. This language is consistent with exis ting UIC requirements for other well classes and EPA’ s authority under the SDWA.

EPA clarifies that the Agency expects that owners or operators should take care not to damage the well when ceasing injection under §146.94(b)(1). At §146.94(b)(2), EPA is maintaining the requirement to “characterize the release.” In order to prevent the endangerment of USDWs, as required under §1421 of the SDWA, EPA expects the owner or operator to act preemptively and not wait until endangerment has occurred. This language is consistent with existing UIC requirements for other well classes and EPA’s authority under the SDWA.

Concerning commenters’ suggestions for §146.94(b)(3), EPA clarifies that the 24 hours begins when the owner or operator obtains evidence of possible endange rment. EPA believes the rule language is clear on this requirement.

Since proposal, EPA has modified the final regulatory language at §146.94(d) to clarify what constitutes a workover to address a well fa ilure (which invokes remedial ac tions) and what constitutes a maintenance-type workover. For maintenance-type workovers (i.e., those that are scheduled in advance), the owner or operator must notify a nd gain approval from the Director prior to beginning the workover. In the final GS regulation, EPA has moved this re quirement to the reporting requirements at §146.91(d) to clarify its intent.

Regarding concerns that notification could delay responses, EPA clarifies th at the GS rule, at §146.94 (b), describes procedures owners or operators must take in em ergency situations. Specifically, upon determining that there is a problem with the well that may endanger a USDW, the owner or operator must first cease injection, then take all steps reas onably necessary to identify and characterize any release, notify the Director, and implement the approved emergency and remedial response plan, which may include a well workover. EPA believes that ceasing injection (which the owner or operator would do immediately and before notifying the Director) is the immediate action ne cessary to prevent or mitigate endangerment of USDW s, as required under the SDWA.

Other EPA Comment Codes and Descriptions: 5260 2.8.2.3 Adjusting the post-injection timeframe (seeking comment) Comment: Proposed Rule: (4) If such a demonstrati on cannot be made (i.e., if the carbon dioxide plume and pressure front have not stabilized) after the 50 year period, the owner or operator must submit to th e Director a plan to continue postin

j ection site care. Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24970Schlumberger Suggested Revision: Delete

Schlumberger Rationale: No longer necessary

Response: As described above, EPA believes that a default post-injection site care timeframe of 50 years, with allowance of Director's discretion to shorten or lengthen this timeframe or approve an alternative PISC time frame, is appropriate to ensure that USDWs are protected, while accounting for the variety of site-specific circumstances that may come in to play at GS sites. EPA expects that the Director would consider the types of inform ation the commenter describes in determining whether the plume and
p ressure front no longer pose a risk of endangerment to USDWs and post- injection site care monitoring may be discontinued.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: Proposed Rule: (viii) Type or grade of cement; and

Schlumberger Suggested Revision: (viii) T ype or grade of cement; and additives

Schlumberger Rationale: -

Response: EPA agrees with the suggestion that §146.86(b)(1 )(viii) be revised to also address cement additives. In the final GS rule, the subparagraph read s as follows: "Type or gr ade of cement and cement additives."

Comment: -Prevention of "endangerment" of drinki ng water is a legislative requirement. Moreover, as noted in Section II.B. of the Preamble, Congress has defined endangerment to activities which "may resu lt" in a system not meeting drinking water regulatory requirements, or otherw ise affecting health. However, EPA appears to have defined the word "may " to include an additional level of
p ossibility in stating, for example, th at the post-injection site care period ends when there is "no potential threat of endangerment." Because "endangerment" is such a central theme throughout this regulation, we recommend that the rule clearly state that EPA interprets endangerment to mean "a reasonable likelihood" of damage based upon an objective assessment of genuine risk and not derived through any mathem atically hypothesized possibility of damage.

Response: The primary goal of the UIC program under the SDWA is to protect USDWs from endangerment. The UIC program provides that no injection shall be authorized if it results in “the movement of fluid containing any contaminant into [USDW]s, if the presence of that contaminant may cause a violation of any primary drinking water regulation under 40 CFR part 142 or may adversely affect the health of persons,” per §144.12.

The Class VI GS rule, as part of the UIC pro g ram re g ulations, continues the pro g ram’s g oal of ensurin g Commenter Name: Andrew Du g ui d Letter ID: 0226 Commenter Or g anization: Schlumber g er Carbon Services Comment ID: 24971

Commenter Name: Ben Yama g ata Letter ID: 0227 Commenter Or g anization: Coal Utilization Research Council Comment ID: 21785the protection of USDWs from endangerment. The permit ting, siting, construction, operation, monitoring, and post-injection site care requirements in the Class VI GS rule are built on a long-standing
p rotective regulatory framework, tail ored to the unique aspects of CO2 GS. Defining endangerment is outside the scope of the Cl ass VI GS rulemaking.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: - Minimum criteria for siting: We request that EPA revise proposed section 146.83(a) to say that "Owners or operators of Class VI wells must demonstrate to the satisfaction of the Director that the wells will be sited in areas with a suitable geologic system, and in a manner that will not adversely impact the safe operation of nearby natural gas underground storage facilities, in compliance with applicable safety regulat ions and guidelines of the Department of Transportation." (Requested amended language in italics.) Further, the required geologic assessment should include analysis of potential leak paths through faulting, fracturing, or other migration paths from injected CO2 in formations in close proximity above or below a natural gas storage formation.

Response: EPA believes that the extensive requirement s for geologic site characterization (at §146.82), AoR evaluation (§146.84), and testing of the well during drilling (§146.87) are appropriate to ensure that
p ermitting authorities have the necessary information to evaluate whether a specific site will allow safe injection of CO2. EPA adds that submittal and review of monitoring data (as required at §146.90) and the AoR reevaluation process (§146.84(e)) will provide an opportunity for an ongoing review of the site and a dialogue between the Director and the owner or operator to en sure that the project is being operated in a manner that protects USDWs from e ndangerment. EPA believes that any natural gas storage operations would be found in site charac terization as would any faults or fractures.

Other EPA Comment Codes and Descriptions: 3420 2.2.2.1 Scope of the inventory process (e.g., reliance on publicly available in formation, depth of wells) Comment: [In the paragraph below the text in all CAPS denotes added text.] §146.82(e): "A tabulation COMPILATION of all wells wi thin the area of review which penetrate the injection or confining zone(s). TO SUPPLEMEN T AND/OR VERIFY INFORMATION OF PUBLIC RECORD, OPER ATORS SHALL USE REASONABLE METHODS TO IDENTIFY THE PRESENCE WELLS WITHIN THE AREA OF REVIEW THAT PENETRATE THE INJECTION OR CONFINING ZONE(S). Such data must include a description [...]"

Response: EPA is retaining the requirement, which is now found in §146.82(a)(4), as proposed. EPA notes that the Director has the discretion in §146.84(c) (2) to require the owner or operator to supplement a data records search—including the use of ground, airborne, or geophysical (e.g., magnetic) surveys—i f there is reason to believe that the incompleteness of available information could compromise USDW
p rotection from endangerment. EPA adds that all corrective action must be performed pursuant to the approved AoR and corrective action plan, which affords the Director the discretion to require an y Commenter Name: Pamela A. Lacey Letter ID: 0228 Commenter Or g anization: American Gas Associatio n Comment ID: 21803

Commenter Name: Kristin Henr y Letter ID: 0242 Commenter Or g anization: Sierra Environmental Law Pro g ram, Sierra Club Comment ID: 23331additional information needed (including information th at is not publically availa ble) to ensure that all necessary corrective action is perf ormed. EPA is developing guidance on AoR and corrective action at GS Class VI sites to assist owne rs or operators and Directors in evaluating requirements and proposed AoR and corrective action plans under 146.84. The guida nce describes EPA's recommended approaches for the data to be considered in an initial AoR delineation, how to apply computational modeling to delineate the AoR, performing corrective action at GS sites, and, when appropriate, completing AoR reevaluations. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3420 2.2.2.1 Scope of the inventory process (e.g., reliance on publicly available in formation, depth of wells) Comment: [In the paragraph below the text in all CAPS denotes added text.] "Using methods approved by the Director, identify all penetrations, including active and abandoned wells and underground mines, in the area of review that may
p enetrate the confining zone OR OTHERWIS E ACT AS CONDUITS FOR FLUID MOVEMENT INSIDE OR OUTSIDE THE CONFINING ZONE".

Response: For the reasons described in the response ab ove, EPA is retaining the requirement as
p roposed.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: The rule should incorporate a "non-interference principle" to keep one sequestration project from interfering with the effectiveness of another

As EPA notes in the preamble (page 43506) , "it is ... possible that multiple owners or operators will be injecting CO 2 into formations that are hydraulically connected and thus the elevat ed pressure zones may inte rsect or interfere with each other." Our Environmental NGO Group agrees that this is a genuine
p ossibility at this stage in GS implem entation. Until comprehensive approaches to basin-scale management are developed, we urge the adoption of the following addition to §146.94:

"(e) If an owner or operator obtains evid ence that a pressure front associated with one geologic sequestration project inte rsects or threatens to intersect a
p ressure front associated with any ot her project, the owner or operator obtaining such evidence must notify th e Director and the other owner or operator. If the Director determines that the pressure front associated with one
p roject interferes or threatens to interf ere with the ability of a project that began operations at an earlier date to sequester the earlier project’s total anticipated volume of the carbon dioxide stream as determined under §146.83(a), the Director may require the owner or operator of the project that began operations at a later date to modify operations as necessary to avoid such interference." Commenter Name: Kristin Henry Letter ID: 0242 Commenter Or g anization: Sierra Environmental Law Pro g ram, Sierra Club Comment ID: 23333

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22285Response: EPA agrees with the commenter that there are a variety of factors that may affect the need for emergency and remedial response at GS sites. EP A believes that the GS Rule adequately protects USDWs from being endangered by multi ple wells. EPA has decided not to adopt the commenter’s edit. However, the Agency believes that a site-specifi c emergency and remedial response plan that is informed by required site characterization data (per §146.82), modeling for AoR evaluations and reevaluations (per §146.84), and monitoring data (per §146.90) will appropria tely address commenter concerns regarding the potential impacts of multiple GS projects. EPA has added a requirement at §146.94(d) that owners or operators mu st review their emergency and reme dial response plan within one year of an AoR reevaluation required under §146.84 or following significant changes to the facility. Subsequently, the owners or operators must submit an amended plan or demonstr ate to the Director that no amendment to the plan is needed based on the AoR reevaluation or any significant changes made to the facility.

EPA also encourages owners or operators and pe rmitting authorities to communicate planned GS activities during initial permitting activities to maximize coordination and minimize pressure interference. If a permit applicant (or the permitti ng authority) is aware of pending GS projects near a
p roposed well, the AoR delineation performed pursu ant to §146.84 should account for the impacts of multiple owners and operators injecting within a single basin. EPA expects that, where multiple operators are involved, the Director will not approve modeling that does not account for changes that may result from all injection operations.

EPA expects that changes within the AoR, such as the addition of new well s or projects that could
p otentially interfere with a GS proj ect, will be identified as part of the AoR reevaluations required at §146.84(e) and would need to be addr essed in a revised emergency and remedial response plan. EPA is developing guidance on the development and implementa tion of project plans fo r GS sites, including emergency and remedial response plans.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: The definition of "carbon di oxide stream" should not be restricted to CO2 captured from industrial sources

The definition of "carbon dioxide stream" in §146.81( b) includes only carbon dioxide "that has been captured from an emission source (e.g., a power plant)." Over time, the vast majority of sequestered CO2 is likely to be captured from such sources, but rules are also needed to govern the sequestration of naturally occurring CO2 produced from geologic formations. We suggest that the definition be revised to read as follows:

[In the paragraph below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf , starting on p. 10, to see the original formatting.]

"Carbon dioxide stream means that has been captured from an emission source (e.g., a power plant), carbon dioxide plus incidental associated substances derived from the source materials OF THE CO2 AND/OR the capture process, and any substances added to the stream to en able or improve the injection process. This subpart does not appl y to an y carbon dioxide stream that meets the Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22293definition of a hazardous wa ste under 40 CFR part 261."

Response: EPA disagrees with the suggested edit. The fi nal definition of car bon dioxide stream at §146.81(d) remains unchanged and reads as follows: “[C]arbon dioxide that has been captured from an emission source (e.g., a power plant), plus incidental associated subs tances derived from the source materials and the capture process, and any substances added to the stream to enable or improve the injection process. This s ubpart does not apply to any carbon dioxide stream that meets the definition of a hazardous waste under 40 CFR part 261.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3440 2.2.2.2 Evaluation of wells in the AoR (e.g., types of data to be reviewed) Comment: In proposed §144.55(a) the rule would require Class I, II (other than existing), III or VI permit applicants to identify the location "of all known wells within the injection well’s area of review which penetrate the injection zone" or, in the case of Class II wells operating over the fracture pressure of the injection formation, "all known wells within the area of review penetrating formations affected by the increase in pressure".

Since injection in deep saline formations will result in an area of elevated
p ressure (above the original reservoir pressure) that will be larger than the CO2 plume and could affect overlying or underlying formations, we believe that the latter requirement for Class II wells operating above the fracture pressure should also apply to Class VI wells. This would help prevent the unwanted migration of reservoir flui ds from outside the inject ion zone through existing wells in the confining zone, as a result of the pressure increase. We therefore suggest that §144.55(a) be revise d to read as follows:

[In the paragraph below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf to see the original formatting.]

"Coverage. Applicants for Class I, II, (other than existing), or III, or VI injection well permits shall identify the location of all known wells within the injection well's area of review which pene trate the injection zone. In the case of Class II wells operating over the fracture pressure of the injection formation, applicants shall identify the location of all known wells within the area of review penetrating formations affected by the increase in pressure. Applicants for Class VI SHALL IDENTIFY TH E LOCATION OF ALL KNOWN WELLS WITHIN THE AREA OF REVIEW PENETRATING THE INJECTION ZONE AND ALL KNOWN WELLS WHICH PENETRATE FORMATIONS AFFEC TED BY THE INCREASE IN PR ESSURE AND shall perform corrective action as specified in Sec. 146.84."

Response: The final rule leaves §144.55 unchan g ed; i.e., Class VI wells ar e not addressed in this Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22295p rovision. Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment, EPA has made many revisions to the GS Rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: Emergency and remedial response, including response to potential problems relating to geologic features, is a necessary complement to corrective action and should remain in the rule. While wells are the most likely conduits for fluid movement into USDWs, the definition of corrective action and the relevant
p rovisions in §146.84 do not take into account the potential for geologic features, such as faults, spill points or fractures, to act as conduits for CO2 or other fluid migration, and hence breach of confinement. Actions to mitigate or remediate a potential breach of conf inement, or a situation which might eventually lead to a breach of confinement, should not be limited to corrective action on wells. We therefore strongly s upport EPA’s inclusion of the Emergency and remedial response section. We propose two minor changes - change §146.94(b) (4) to read:

[In the paragraphs below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf to see the original formatting.]

"Implement the emergency and remedi al response plan approved by the Director, AND KEEP HIM APPRIZED OF THE IMPLEMENTATION."

and §146.94(d) to read:

"The owner or operator must notify the Di rector and obtain his approval prior to conducting any well workover OR OTHER REME DIATION MEASURES NOT LISTED IN THE EMERGENCY AND REMEDIAL RESPONSE PLAN."

Response: The final rule keeps the langua ge in §146.94(b)(4) as proposed. EP A agrees that the Director should be kept apprised of progress on the implemen tation of the emergency a nd remedial response plan and expects that the plan itself will include provisions on communicati ons with the Dire ctor. EPA agrees that an emergency and remedial re sponse plan is an important part of assuring protection of USDWs from endangerment at GS sites. The requirements fo r an emergency and remedi al response plan at §146.94(a) are designed to ensure that owners or ope rators, as part of their permit applications, comprehensively plan what actions would be necessary in the unlikely event of an emergency. The plan will ensure that operators know what entities and indi viduals must be notified a nd what actions must be taken to expeditiously mitigate any emergency situations. EPA is developing guidance on the development and implementation of emergency and remedial response plans for GS sites.

Since proposal, EPA has modified the final regulatory language at §146.94(d) to clarify what constitutes a workover to address a well fa ilure (which invokes remedial ac tions) and what constitutes a maintenance-type workover. For maintenance-type workovers (i.e., those that are scheduled in advance), the owner or operator must notify a nd gain approval from the Director prior to beginning the workover. In the final GS re g ulation, EPA has moved this requirement to the reportin g requirements at §146.91(d) Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22299to clarify its intent.

Regarding concerns that notification could delay responses, EPA clarifies th at the GS rule, at §146.94 (b), describes procedures owners or operators must take in em ergency situations. Specifically, upon determining that there is a problem with the well that may endanger a USDW, the owner or operator must first cease injection, then take all steps reas onably necessary to identify and characterize any release, notify the Director, and implement the approved emergency and remedial response plan, which may include a well workover. EPA believes that ceasing injection (which the owner or operator would do immediately and before notifying the Director) is the immediate action ne cessary to prevent or mitigate endangerment of USDW s as required under the SDWA.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: The definition of "confining zone" should not be limited to formations overlying the injection zone, and should focus on li miting movement through the confining zone rather than out the injection zone

The proposed definition of confining zone in §146.81(d) requires that the formation act as "a barrier" to fluid movement, which may be unnecessarily strict. The definition also fails to recognize that it is movement through and beyond the confining zone that needs to be limited. We suggest instead that the definition of "confining zone" read as follows:

[In the paragraph below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf to see the original formatting.]

"Confining zone means a geol ogic formation, group of form ations, or part of a formation stratigraphically overlying the injection zone that acts as a barrier to limit fluid movement beyond THIS FORMATION, GROUP OF FORMATIONS, OR PART OF A FORMATION."

Response: EPA disagrees with the suggested edit. Howe ver, the Agency has modified the final definition of confining zone at §146.81(d) to read as follows: “[A] geologic formation, group of formations, or part of a formation stratigraphically overlying the injection zone that acts as barrier to fluid movement. For Class VI wells operating under an injection depth waiver, confining zone means a geologic formation, group of format ions, or part of a formation stratigraphically overlying and underlying the injection zone.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1220 1.1.1.1 Terminology and definitions Comment: The second sentence of the definition of ‘geologic sequestration project" should b e amended to refer more g enerall y to formation fluids and be transferred to the Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22300

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22301definition of "area of review"

We suggest the following amendment to §146.81(d) in order to be more inclusive on the types of fluid that could be displaced:

[In the paragraph below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf to see the original formatting.]

"[...] It includes the subsurface three-dimensional extent of the carbon dioxide
p lume, associated pressure front, and displaced brine FORMATION FLUIDS, as well as the surface area above that delineated region.

We also suggest that this second sent ence of the definition of geologic sequestration project be transferred to the definition of area of review as recommended above. The language provided a bove reflects the change from "brine" to "formation fluids."

Moreover, we suggest that the present re striction of Class VI to formations below the lowermost USDW is more appropria tely addressed elsewhere. Accordingly, we recommend that geologic sequestrati on project be defined as follows:

[In the paragraph below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf to see the original formatting.]

"Geologic sequestration project means an inj ection well or wells used to emplace a carbon dioxide stream beneath the lowermost formation containing a USDW INTO AN INJECTION ZONE FOR GEOLOGIC SEQUESTRATION. It includes the subsurface three

dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surfa ce area above that delineated region."

The term "pressure front" should be replaced with the more acc urate term "area of elevated pressure" throughout the rule

The term "pressure front" in 146.81(d) is like ly to be scientifically inaccurate as it implies a front, or discontinuity in pressure, whereas in reality there will be a continuous pressure gradient in the formation in most cases. We suggest globally replacing "p ressure front" with "area of elevated pressure" throughout the rule.

Response: EPA disagrees with the suggested edit. However, the Agency has modified the definition of geologic sequestration project at §146.81( d) to read as follows: “Geo logic sequestration project means an injection well or wells used to emplace a carbon dioxide stream beneath the lowermost formation containing a USDW; or, wells used for geologic seques tration of carbon dioxide that have been granted a waiver of the injection depth requirements pursu ant to requirements at §146.95; or, wells used for geologic sequestration of carbon dioxide that have received an aquifer exemption expansion. It includes the subsurface three-dimensional extent of the carbon dioxide plume, associated pressure front, and displaced brine, as well as the surface area above that delineated region.”

The final definition of pressure front at §146.81(d) also is unchanged and reads as follows: “[T]he zoneof elevated pressure that is created by the injection of carbon dioxide into the subsurface. For the
p urposes of this subpart, the pressure front of a carb on dioxide plume refers to a zone where there is a
p ressure differential sufficient to cause the movement of injected fluids or formation fluids into a USDW.”

Based on its evaluation of all publ ic comments and input on the proposed rule and the NODA and Request for Comment, EPA has made many revisions to the Class VI GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 1616 1.3.1.3 Fluid movement Comment: The term "transmissive fault or fracture" should be clarified

The proposed rule in §146.83(a)(2) requires a confining zone(s) that is free of transmissive faults or fractures, while §146.81 defines this term as "A fault or fracture that has sufficient permeability a nd vertical extent to allow fluids to move between formations". We suggest the following modi fication to the definition in §146.81(d) in order to avoid unduly restricting move ment that is merely between formations (compare our comments above on the definition of "confining zone"):

[In the paragraph below the text in all CAPS denotes adde d text. See also EPA-HQ-O W-0390-0250.pdf to see the original formatting.]

"Transmissive fault or fracture means a fault or fracture that has sufficient
p ermeability and vertical extent to al low fluids to move between formations BEYOND A CONFINING ZONE."

Response: EPA has retained the definition in the final rule . While there may be cases, as the commenter suggests, where a transmissive fa ult may exist but not pose a concern for confinement, i.e., in the context of all other information, EP A believes the definition is accura te. Based on its evaluation of all
p ublic comments and input on the proposed rule a nd NODA and Request for Comment EPA has made many revisions to the GS Rule. See the final rule a nd the geologic site characte rization discussion in the
p reamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3120 2.1.2 Need to identify additional confining and containment zones (seeking comment) Comment: Secondary confining zone

§146.83 allows the Director to require additional confining zones, at his discretion. We do not believe that this will always be necessary - a good
p rimary zone should be sufficient. Wh ere additional hazards justify it, a secondary zone might be desirable. In all cases, we caution against relying on secondary confinement in place of esta blishing with a greater degree of certaint y the suitabilit y of the primar y zone. Potential problems are best Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22304

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22305identified and anticipated early, and the focus should be on site characterization to show with confid ence whether the confining zones are adequate. We suggest striking part (b) in §146.83 as it seems redundant. However, the Director must have the disc retion to require a secondary confining zone if needed. We ther efore recommend clarifying part (a)(2) to read explicitly:

[In the paragraph below the text in all CAPS denotes adde d text. See also EPA-HQ-O W-0390-0250.pdf to see the original formatting.]

"A confining zone, or zones , that is ARE free of transmissive faults or fractures and of sufficient areal extent and integrity to contain the injected carbon dioxide stream and displaced format ion fluids and allow injection at
p roposed maximum pressures and volume s without initiati ng or propagating fractures in the confining zone(s)"

Response: EPA disagrees with the suggested edit, but agrees that providing the Director discretion will allow consideration of a range of sites for GS, ba sed on site-specific conditions and ensure USDW
p rotection. EPA believes that requiring appropriate si te characterization by the owner or operator (under §146.82) and providing an appropriate degree of flexibility to the Director to evaluate site-specific geologic data will afford the greatest protection of USDWs from endangerment. The Agency believes that in some geologic settings, th e presence and identification of a dditional confining and containment zones above the primary (i.e., lowermost) confining zone can improve USDW protection. These formations could further impede vertical fluid m ovement, allow for pressure dissipation, and provide additional sites for monitoring, mitigation, and remedi ation, while also affording the greatest protection of USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: An additional concern is that both §146.81 and §146.84(a) state that the AOR is "based on computational modeling". This could imply that the Area of Review could be based solely on computationa l modeling. Instead, the AOR should be based on computational modeling, monito ring and operational data (and kept updated until closure is approved). All re ferences to computational modeling in relation to the Area of Review in this se ction, as well as in the definition of Area of Review in §146.81 shoul d be amended as appropriate to read "based on computational modeling, as we ll as monitoring and other operational data." We urge that the definition be revised as follows:

[In the paragraph below the text in all CAPS denotes adde d text. See also EPA-HQ-O W-0390-0250.pdf to see the original formatting.]

"Area of review means the AREA that may be impacted by the in jection activity. The area of review is based on computationa l modeling, as well as MONITORING AND OTHER OPERATIONAL DATA, that account for the physical and chemic al properties of all phases of the in j ected carbon dioxide stream. IT INCLUDES THE SUBSURFACE Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22307THREE-DIMENSIONAL EXTENT, THROUGHOUT THE OPERATING LIFE OF THE FACILITY, OF THE CARBON DIOXIDE STREAM PLUME, ASSOCIATED PRESSURE FRONT, AND DISPLACED FORMATION FLUIDS, AS WELL AS THE OVERLYING FORM ATIONS AND SURFACE AREA ABOVE THAT DELINEATED REGION."

Response: Based on review of all public comments on th e AoR definition at 146.84(a), the Agency has modified it to read as foll ows: "The region surrounding the ge ologic sequestration project where USDWs may be endangered by the injection activit y. The area of review is delineated using computational modeli ng that accounts for the physical and chem ical properties of all phases of the injected CO2 stream and is base d on available site characterizati on, monitoring, and operational data." The definition in the proposed rule accounted for the varying physical and chemical properties of the CO2 including free-phase and water-dissolved CO2, as the commenter suggests. The definition in the final rule will continue to do so.

EPA is developing guidance on AoR and corrective action at GS Class VI sites to assist owners or operators and Directors in evaluating requirements and proposed AoR and corrective action plans under 146.84. The guidance describes EPA's recommended appro aches for the data to be considered in an initial AoR delineation, how to apply computational modeling to delineate the AoR, performing corrective action at GS sites, and, when appropriate, completing Ao R reevaluations. The guidance will be available on EPA's web site, at http://water .epa.gov/type/groundwater/uic/wells_sequestration.cfm.

EPA clarifies that the initial Ao R delineation required under 146.84(c) is performed prior to injection, and therefore no monitoring or opera tional data would yet exist. Th e AoR delineation models will incorporate all available site da ta and anticipated operating procedures (e.g., injection rates and volumes).

The AoR reevaluation process required at 146.84(e) requires owners or operators to incorporate monitoring or operational data and make any needed adjustments to corrective action or monitoring at the site. EPA believes that the iterat ive process of AoR reevaluation is a ppropriate to verify that the CO2
p lume and pressure front are moving through the subs urface as predicted, verify the accuracy of the delineation model (or identify needed changes), and refine testing and monitoring activities to ensure that USDWs are protected from enda ngerment and that there would be adequate warning of potential
p roblems at the site before a ny endangerment could occur.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: In particular, monitoring above the caprock, sometimes informally referred to as "above-zone monitoring, and covered in (d), is a tested monitoring method [FN23], and one that can be key to verifying the inte grity and lateral extent of the caprock (or confining zone). We support its inclus ion, but also recognize that it might not be necessary to employ this method ev ery time. We would only consider its omission acceptable only if another method capable of testing and verifying the integrity of the confining zone is being used. Subpart (d) would also cover groundwater monitoring near the surface, at a long distance from the caprock. It is our understanding that researchers fr om the Lawrence Livermore National Laborator y are alread y confident in the merits of this approach and its accurac y Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22319in detecting small amounts of CO2. We ther efore recommend the following minor changes to §146.90(d):

[In the paragraph below the text in all CAPS denotes adde d text. See also EPA-HQ-O W-0390-0250.pdf to see the original formatting.]

"Periodic monitoring of the ground water quality and GEOPHYSICAL, geochemical OR OTHER changes above the confining zone(s) th at may be a result of carbon dioxide OR OTHER INDUCED fluid movement thr ough the confining zone or additional identified zones; provided however that the DIRECTOR MAY INSTEAD REQUIRE THE INCLUSION OF OTHER METHODS THAT TEST AN D/OR VERIFY THE INTEGRITY OF THE CONFINING ZONE(S) WITH SIMILAR ACCURACY AND TO THE SAME OR LARGER AREAL EXTENT.(1) [...]"

[FN23: Used successfully at the Frio pilot project, and already being considered for other projects.]

Response: EPA clarifies that direct monitoring of ground water quality above th e confining zone is important, and the GS rule requires this at §146.90(d) . EPA believes that the ground water geochemical monitoring outlined in §146.90(d) will maximize protection of USDWs fro m endangerment at GS sites. Additional monitoring above the confining zone, as well as monito ring in additional fo rmations, e.g., the injection zone, may also be necessa ry, and if the Director believes such monitori ng is warranted he/she has the authority under §146.90(i) to require that it be included in the testing and monitoring plan.

EPA adds that the baseline geochemical data requi red with the permit application at §146.82(a)(6) will
p rovide information on predicting potential interact ions between rocks and CO2 as the commentersuggests, and also expects that this information will inform the development and approval of a sitespecific testing and monitoring pla n. EPA expects that the data will also help determine whether any changes are occurring above the confining zone and whether they might be associated with the CO2
p lume or pressure front.

EPA further clarifies that the final rule at §146.90(g) requires indirect monitoring not above the confining zone but in the injecti on zone, unless the Director determ ines, based on site-specific geology, that indirect methods are not appropriate. Indirect methods can include geophysical methods.

Other EPA Comment Codes and Descriptions: 4650 2.6.5 CO2 plume and pressure front tracking (seeking comment) Comment: To capture the points made a bove and resolve current ina ccuracies or limitations in the proposed language, we recommend the following additional changes in §146.90(g):

[In the paragraph below the text in all CAPS denotes adde d text. See also EPA-HQ-O W-0390-0250.pdf, to see the original formatting.]

"(1) Testing and monitoring to track ESTABLISH the extent of the carbon dioxide plume and the posi tion of the pressure front WITHIN DEFINED Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22325THRESHOLDS, WITH THE ASSISTANCE OF MODELING TOOLS WHERE APPROPRIATE AND THROUGH DIRECT MEASUREMENTS OR INDIRECT, GEOPHYSICAL OR OTHER TECHNIQUES by either monitoring for pressure changes in the first formation overlying the confining zone or using indirect, geophysical techniques (e.g., seis mic, electrical, gravity, or electromagnetic surveys and/or down

- hole carbon dioxide detection tools); (2) TESTING AND MONITORING TO ESTABLIS H THE EXTENT OF THE AREA OF ELEVATED

PRESSURE THROUGH DIRECT MEASUREMENTS AND THE ASSISTAN CE OF MODELING TOOLS."

and in §146.90(h):

[In the paragraph below the text in all CAPS denotes adde d text. See also EPA-HQ-O W-0390-0250.pdf, to see the original formatting.]

"At the Director’s di scretion, surface air monitoring METHODS and/or soil gas monitoring to detect movement of car bon dioxide that could SIGNAL endangerMENT OF a USDW. (1) The testing and monitoring plan must be based on potential vulnerabilities within the area of review; (2) The monitoring frequency and spatial distribution of surface air monitoring and/or soil gas monitoring must reflect baseline data and the monitoring plan must include how the pr oposed monitoring will yield useful information on the area of review delineat ion and/or compliance with standards under 40 CFR 144.12"

Response: As described above, EPA believes that direct pressure measurements ar e appropriate and that direct pressure monitoring will be f easible at all GS sites and retains this provision in the final GS rule, at §146.90(g).

EPA acknowledges that air and soil gas monitoring to ensure USDW pr otection is not necessary at all GS sites and agrees that the decision to use surfac e monitoring and the selection of monitoring methods for the purpose of USDW protec tion will be site-specific.

The Agency believes that surface air and soil gas monitoring, when coupled with subsurface monitoring, may be appropriate at some GS projects to en sure USDW protection. EPA also acknowledges that surface air and soil gas measurements are subject to va riability and may not be suitable in all settings as a method to ensure USDW protection. However, EPA doe s not believe that this should entirely preclude their use. The decision to use surf ace monitoring and the se lection of monitoring me thods will be sitespecific (e.g., may be influenced by geology, inject ion depth, and operational conditions) and must be based on potential risks to USDWs within the AoR.

In the final rule, at §146.90(h), the decision to requi re such monitoring as an additional measure to ensure USDW protection rests with th e Director as a means of identify ing leaks that may pose a risk to USDWs and informing emergency notif ication of a Class VI owner or operator and UIC Director in the event of a USDW endangerment, pursuant to requirements at §146.91(c).

Based on its evaluation of all public comments and input on the proposed rule and NODA and Requestfor Comment EPA has made many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 1620 1.3.2 Induced seismicity Comment: [In the paragraph below the text in all CAPS denotes adde d text. See also EPA-HQ-O W-0390-0250.pdf, to see the original formatting.]

"Information on seis mic history including the presence and depth of seismic sources and aN ASSESSMENT OF that WHETHER SUCH seismicity would not interfere with containment;"

In addition, language should be added to the minimum criteria for siting in §146.83, clarifying that if induced or na tural seismicity poses unacceptable risks, a permit will not be granted. In order properly to assess the risk of significant induced seismicity in light of permitted opera ting conditions, the rule may need to require applicants to submit information beyond what is currently required in proposed §146.82. The effects of any seismic events during
p roject operation should also be ta ken into account when updating, or considering whether to update, the Area of Review and Corrective Action Plan, the Testing and Monitoring Pl ans, and the Emergency and Remedial Response Plans, as well as any other plans as necessary.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the final rule and
p reamble discussion of geologic site characterization for further di scussion on EPA's final approach.

EPA clarifies that under §146.82(a)(21), the Director has the authority to require additional information to be submitted with the permit a pplication. EPA agrees that seismic ev ents should be taken into account when updating the plans or other pe rmit conditions and clarifies that exis ting language at §144.39(a)(2) allows the Director to modify the permit when he or she receives new informat ion that was not available at the time of permit issuance.

Other EPA Comment Codes and Descriptions: 3420 2.2.2.1 Scope of the inventory process (e.g., reliance on publicly available in formation, depth of wells) Comment: [In the paragraph below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf to see the original formatting.]

§146.82(e): "A tabulation COMPILATION of all wells wi thin the area of review which penetrate the injection or confining zone(s). TO SUPPLEMEN T AND/OR VERIFY INFORMATION OF PUBLIC RECORD, OPER ATORS SHALL USE REASONABLE METHODS TO IDENTIFY THE PRESENCE WELLS WITHIN THE AREA OF REVIEW THAT PENETRATE THE INJECTION OR Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22327

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 25256CONFINING ZONE(S). Such data must include a description [...]"

[FN22: NETL , for example, has developed an electromagnetic system that can be used for areal or ground-based identification of wells (casings).]

Additionally, we believe that problematic wells may not be limited to the confining zone, as would be the case if c onfinement were to be breached, or if
p ressure effects caused by the injection caused fluid movement outside the defined confining zone. We recommend the following modification in §146.84(c) (2):

[In the paragraph below the text in all CAPS denotes added text. See also EPA-HQ-OW-0390-0250.pdf to see the original formatting.]

"Using methods approved by the Director, identify all penetrations, including active and abandoned wells and underground mines, in the area of review that may
p enetrate the confining zone OR OTHERWIS E ACT AS CONDUITS FOR FLUID MOVEMENT INSIDE OR OUTSIDE THE CONFINING ZONE".

Response: EPA is retaining the requirement at §146.82( b), which is now found in §146.82(a)(4), as
p roposed. EPA adds that all corrective action must be performed pursuant to the approved AoR and corrective action plan, which afford s the Director the discretion to require any additional information needed (including information that is not publically av ailable) to ensure that all necessary corrective action is performed. EPA notes that the Director ha s the discretion at §146.84(c)(2) to require the owner or operator to supplement a data records search—i ncluding the use of ground, airborne, or geophysical (e.g., magnetic) surveys—if there is reason to believe that the incompleteness of available information could compromise USDW protection from endangerm ent. For these reasons, EPA is retaining the requirement at §146.84(c)(2) as proposed.

Regarding the concern about identify ing wells other than those that penetrate the confining zone, EPA adds that the Director the discretion to require a ny additional information needed to ensure that all necessary corrective action is perf ormed, including information on well s that are above the confining zone, if site-specific information indicates such a need to ensure USDW protection.

Other EPA Comment Codes and Descriptions: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ dividing line between Class II and Cl ass VI (seeking comment) Comment: The GWPC also recommends EPA consider retaining all geologic sequestration in oil and gas reservoirs under the jurisd iction of Class II UIC programs and create a subclass within this program for geologic storage of carbon dioxide. This subclass (Class II GS) would be used for those wells that depart from the traditional uses of Class II wells for enhanced recovery, and result in the application of Class VI standards. This change woul d eliminate any confusion over whether a Class II CO2 injection well us ed for enhanced recovery might also need a Class VI perm it and would avoid the need to change jurisdiction for a well from one state agency to another over time. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24835Response: EPA disagrees that the risks posed by long term storage of CO2 for GS can be addressed under existing UIC requirements, such as those for Cla ss II wells. EPA believes and the administrative record supports that there are signi ficant differences between how EOR and GS projects are operated, as well as the different risks posed by these different injection activities. The new tailored approach of the GS rule was designed to address the general risks deep injecti on may pose to USDWs and was tailored specifically to address the risks posed by long term storage of CO2 (i.e., very large volumes, very long time-periods, and reservoi r pressure conditions).

In response to the comment on the burden of changing regulatory agencies in the middle of an operation, EPA clarifies that primacy is granted to a state, not to a specific agency within that state, and states may choose which agency implements the Class VI program. States may, for example, choose an environmental quality protection agency (non-Class II ) or the state's traditional oil and gas regulatory agency to implement the Class VI program as long as the program meets the minimum federal requirements for Class VI wells as required under section 1422 of SDWA. Some st ates manage all injection well classes under Section 1422 and through a single agency, while in other states, Class II
p rograms are run by oil and gas agencies.

Regardless of the specific Agency the state sele cts to assume regulatory authority for Class VI operations, the state must obtain primacy for the 1422 Class VI program. Furthermore, the state may determine that a memorandum of understanding (MOU ) between several state agencies regarding specific projects can facilitate this process without needing to change regulatory agencies after Class II
p rojects have transitioned to a Class VI permit.

Other EPA Comment Codes and Descriptions: 2048 1.5.2.4 Oppose Class VI/ Support Class V experimental technology well Comment: EPA Proposal: 4. Adding § 144.15 to read as follows.

§ 144.15 Prohibition of non-experimental Class V wells for geologic sequestration.

The construction, operation or maintenanc e of any non-experimental Class V geologic sequestration we ll is prohibited.

GWPC Recommendations: This provision shoul d be deleted if EPA does limit Class VI wells to injection below the lowermos t USDW in the final rule to allow Directors to selectively authorize GS in areas with USDWs below the injection

zone.

In addition, it is recommended that all GS into basalts, coal seams, salt domes, and shales be conducted under Class V as e xperimental wells initially and then as commercial scale Class V wells/pr ojects if the experi mental projects demonstrate that these sites can be suit able for geological sequestration while
p reventing endangerment of USDWs.

Rationale: Keeping these wells under Class V would allow EPA and the states to gain enough experience to develop suitab le permitting requirements for such wells and to tailor those re quirements until the agencies are ready to adapt the Class VI re g ulations. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24836Response: The text at 144.15 is retained in the fina l regulation; the construction, operation or maintenance of any non-experimental Class V GS well is pr ohibited under the final rule. The final rule contains tailored requirements fo r Class VI wells to ensure that GS projects are permitted sited, constructed, operated, and closed in a manner that does not endanger USDWs.

EPA also clarifies that the final GS rule does not categorically preclude in jection of CO2 into any formation types. Existing experimental GS project s may be permitted as described in UIC Program Guidance #83: Using the Class V Experimental Technology Well Classifi cation for Pilot Carbon Geologic Sequestration Projects, which provided information for permitting authorities to consider when
p ermitting experiment al GS projects (i.e., thos e projects that are designed to test new, unproven technologies, per the definition of a Class V experimental technology well). EPA adds that, following finalization of the GS rule, all GS projects that ar e not for experimental purposes must be re-permitted as Class VI wells and be subject to the final GS requirements. EPA expects that, after promulgation of the final rule, a limited number of expe rimental injection projects to test GS technology will continue, e.g., to inform the technology associat ed with GS into basalts, coal seams, and salt domes.

The Agency also clarifies that it does not consider it appropriate to permit CO 2 injection wells that aretesting the injectivity or appropriateness of an individual formation (e.g., as a prelude to a commercialscale operation) as Class V experime ntal technology wells. Such wells must be permitte d as Class VI wells.

EPA is preparing an addendum to UICPG #83 that describes the use of th e Class V experimental technology well classifica tion to clarify permitting for Class V wells. This addendum will address shifting of Class V experimental projects to full-scale GS projects and the future use of the Class V experimental technology well subcla ss for research and testing of ne w GS technologies. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Comment: Rule Provision: 144.18

EPA Proposal: 5. Adding § 144.18 to read as follows.

§ 144.18 Requirements for class VI wells.

Owners or operators of Clas s VI wells must obtain a pe rmit. Class VI wells are not authorized by rule to inject.

GWPC Recommendations: Support the proposed language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24837

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24838Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment); 5700 2.12 Comments on the proposed durati on of Class VI permit s (seeking comment) Comment: Rule Provision: 144.36

EPA Proposal: 6. Section 144.36 is amended by revising the first two sentences in paragraph (a) to read as follows:

§ 144.36 Duration of permits.

(a) Permits for Class I and V wells shall be effective for a fixed term not to exceed 10 years. UIC Permits for Class II, III and VI wells shall be issued for a period up to the operating lif e of the facility. * * * * * * * *

GWPC Recommendations: Support the proposed language.

Rationale: The proposed provision is c onsidered acceptable as long as the iterative reevaluation proc ess established for AoRs also applies to other aspects of the project including mode ling, characterization, operational decisions, monitoring, financial assuranc e, etc. It is recognized that Directors may also depend on 144.39 regard ing modification and revocation of Class VI permits.

Response: EPA acknowledges the commenter’ s support and notes that the final rule retains this requirement. The final rule maintains the lifetime pe rmit provision and clarifies that the permit extends through the post-injection si te care period (144.36(a)). It also adds a requirement that the Director review each Class VI permit at least once every 5 years to determine whether it should be modified, revoked and reissued, terminated or a minor modification ma de as provided in §§144.39, 144.40, or 144.41. The Director’s review will be informed by the owners’ or operato rs’ iterative reevaluation of the
p roject. Specifically, the final rule includes a requirement that the AoR be reevalua ted at least every five years, and also requires owners or operators to re view and update the AoR and corrective action plan, the testing and monitoring plan, and the emergency and remedial response plan throughout the life of the
p roject (146.84(e), 146.90(j), and 146.94(d)). Owners or operators must review each plan and identify necessary amendments or demonstr ate to the Director that no amendment is needed. In no case can reviews occur less often than once every five years. The iterative process and subsequent plan reevaluations ensure that time and resources are commit ted to the most critical aspects of the permit in
p reventing endangerment to USDW s. EPA believes that the iter ative process of developing and executing the various plans required of GS well operators in the final rule (e.g., for AoR and corrective action, testing and monitoring, inj ection well plugging, post-injection site care, and emergency and remedial response) is tailored to the unique as pects of—and is more appropriate for–GS than establishing a finite permit duration.

EPA emphasizes that the final rule requires owners or operators to revise their cost estimates for financial assurance within 60 days of amendments to the AoR and corrective action plan, the injection well plugging plan, the post-injection site care and site closure pla n, or the emergency and remedial response plan (40 CFR 146.85(c)(2).

EPA emphasizes that, the Dir ector has the authority to revise the pe rmit if project operations change or if the Director believes based on monitoring or operational data that the project may endanger USDWs. EPA has also added text to 144.39(a )(5) that permit modifications w ould be required if the Director determines that a modification is necessary based on an AoR reevaluation, amendments to any of thep roject plans, or a review of the testing and monitoring results. The Di rector may also choose to require minor permit modifications under 40 CFR 144.41, depending on the extent of the plan amendment. All
p ermit modifications, except mi nor modifications under 40 CFR 144.41, require an opportunity for
p ublic comment on the portion of the permit that is being reopened pursuant to requirements under 40 CFR Part 124.

Other EPA Comment Codes and Descriptions: 5900 2.14 Other administrative requirements under 40 CFR 144 Comment: EPA Proposal: 7. Section 144.39 is amended by revising the second sentence in
p aragraph (a) introductory text and by revi sing the second sentence in paragraph (a)(3) introductory text to read as follows:

§ 144.39 Modification or revocation and reissuance of permits.

* * * * *

GWPC Recommendations: Support the proposed language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 5900 2.14 Other administrative requirements under 40 CFR 144 Comment: Rule Provision: 144.39

EPA Proposal: (a) * * * Fo r Class I hazardous waste injection wells, Class II, Class III or Class VI wells the foll owing may be causes for revocation and reissuance as well as modification; and fo r all other wells the following may be cause for revocation or reissuance as we ll as modification when the permittee requests or agrees. * * *

* * * * *

(3) * * * Permits other than for Class I hazardous waste injection wells, Class II, Class III or Class VI wells ma y be modified during their terms for this cause only as follows: * * * * * * * *

GWPC Recommendations: Support the proposed language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowled g es the comment. Please see the remainder of EPA's responses to this Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24839

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24840comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 5900 2.14 Other administrative requirements under 40 CFR 144 Comment: EPA Proposal: (2) When the Director determ ines that a Class I, II, III or VI well lacks mechanical integrity pursuan t to § 146.8 or § 146.89 for Class VI of this chapter, he/she shall give written notice of his/ her determination to the owner or operator. * * *

* * * * *

GWPC Recommendations: Support the proposed language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 5900 2.14 Other administrative requirements under 40 CFR 144 Comment: Rule Provision: 144.52

EPA Proposal: 9. Section 144.52 is amende d by revising paragraph (a)(8) to read as follows:

§ 144.52 Establishing permit conditions.

(a) * * *

(8) Mechanical integrity. A permit for a ny Class I, II, III or VI well or injection project which lacks mechanical integrity shall include, and for any Class V well may include, a condition prohibiting injection operations until the
p ermittee shows to the satisfaction of the Director under § 146.08 or § 146.89 for Class VI that the well has mechanical integrity.

* * * * *

GWPC Recommendations: Support the proposed language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. Fo r additional information on EPA's final re g ulator y approach, please Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24842

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24843see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 5900 2.14 Other administrative requirements under 40 CFR 144 Comment: Rule Provision: 144.55

EPA Proposal: § 144.55 Corrective action.

(a) Coverage. Applicants for Class I, II, (other than existing), III or VI injection well permits shall identify the location of all known wells within the injection well’s area of re view which penetrate the injection zone, or in the case of Class II wells operating over the fracture pres sure of the injection formation, all known wells within the area of review penetrating formations affected by the increase in pressure. A pplicants for Class VI shall perform corrective action as speci fied in § 146.84.* * *

* * * * *

GWPC Recommendations: Support the proposed language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost USDW Comment: Rule Provision: 144.80

EPA Proposal: 11. Section 144.80 is amende d by revising the first sentence in
p aragraph (e) and by adding paragraph (f)to read as follows:

§ 144.80 What is a Class V injection well? * * * * *

(e) Class V. Injection wells not included in Class I, II, III, IV or VI. * * *

(f) Class VI. Wells used for geologic sequestration of carbon dioxide.

GWPC Recommendations: (4) For enhanced re covery of oil or natural gas where geologic sequestration is occurring duri ng or in connection with enhanced recovery of oil or natural gas provided (i) there is reasonable expectation of more than insignificant future production vol umes or rates as a result of carbon dioxide in j ection and (ii) operatin g pressures are no hi g her than reasonabl y Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24844

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24845necessary to produce such volumes or rates;

(f) Class VI. Wells inj ecting a carbon dioxide stream for geologic sequestration except those wells described in subsection (b)(4) of this section or otherwise excluded from this Class.

Rationale: There should not be a blanket prohibition c oncerning injection above USDW’s or at specific levels. The dete rmination of injection zones should be based upon appropriate containment. This is especially true in light of recent calls for changes in the definition of a US DW to include formations greater than 10K PPM TDS and the fact that several st ates including Wyoming and California might be prevented from instituting geol ogic sequestration as a practical matter if injection were limited to above USDW’s due to the great depth of some USDW’s. This would create a situation wher e otherwise good injection zones are artificially excluded, thus decreasing the overall availabili ty of geologic sequestration in the U.S.

The GWPC also recommends EPA consider retaining all geologic sequestration in oil and gas reservoirs under the jurisd iction of Class II UIC programs and create a subclass within this program for geologic storage of carbon dioxide. This subclass (Class II GS) would be used for those wells that depart from the traditional uses of Class II wells for enhanced recovery, and result in the application of Class VI standards. This change woul d eliminate any confusion over whether a Class II CO2 injection well us ed for enhanced recovery might also need a Class VI perm it and would avoid the need to change jurisdiction for a well from one state agency to another over time.

Response: EPA acknowledges that there are limited circum stances where injectio n above the lowermost USDW can be performed in a manner that protects USDWs from endangerment, as long as appropriate
p rotections are in place. The fina l GS rule at §146.95 establishes a pro cess by which owners or operators can seek a waiver of the Class VI injection depth requirements for injection into non-USDW formations above and/or between USDWs. It establishes: 1) requirements specifying information that owners or operators must submit, and Director s must consider, in consultation wi th PWSS Directors; 2) procedures for public notice of a waiver application and for Di rector-Regional Administra tor communication; 3) the waiver issuance process; and, 4) a dditional requirements that apply to owners or operators of Class VI wells granted a waiver of the injection depth requir ements to ensure USDW protection above and below the injection zone.

EPA adds that it has revised the definition of a Class VI well to read as follows: “Wells that are not experimental in nature that are used for geologic sequestration of carbon dioxide beneath the lowermost formation containing a USDW; or, wells used for ge ologic sequestration of carbon dioxide that have been granted a waiver of the in jection depth requirements pursuant to requirements at §146.95 of this chapter; or, wells used for geologi c sequestration of carbon dioxide that have received an expansion to the areal extent of an existing Class II enhanced oil recovery or enhanced gas recovery aquifer exemption pursuant to §§146.4 of this chapter and 144.7(d).”

For additional information on the waiv er approach, please se e the final rule and preamble, as well as EPA's responses to comments on the Notice of Data Availability and Request for Comment.

In response to the comment that GS wells should be regulated as Class II wells, EPA believes that injection for the primary purpose of long term storage is sufficient ly different from Class II ERoperations and warrants tailored requirements. Fo r example, the volume of CO2 anticipated to be injected in Class VI wells is significantly greater than for Class II wells. Reservoir pr essure conditions will also be different, with Class VI injection operations involving large volumes of CO2 and likely having higher pressures within their storage formations than Class II ER projects. The Director has the authority to determine at what point a Class VI perm it is required for those pr ojects that are transitioning from the primary purpose of EOR to long term storage of CO2. The fi nal regulation pr ovides a set of technical factors for the Director to evaluate in making this determin ation, at §144.19. EP A believes that this approach provides suff icient protection of USDWs when there is an increased risk to USDWs as compared to traditional Class II operations while allowing for site-spe cific flexibility. EPA is developing guidance on transitioning permits from Class II to Class VI. The guidance will assist Directors in determining whether an injection project should be transitioned from Class II where the primary purpose is oil and gas production to Class VI where the primary purpose is long-term storage of large volumes of CO2. This guidance will be av ailable on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

EPA also recognizes that there is increasing demand for water resources and that technology improvements may make high TDS aquifers viable drinking water sources. However, EPA is not changing the USDW definition; changing the definiti on of a USDW is outside the scope of the GS rulemaking. The GS rule focuses on ensuring prot ection of USDWs, as required under the SDWA, by establishing regulations to ensure the safe injection of CO2 for long-term storage.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 144.51

EPA Proposal: 8. Section 144.51 is amende d by revising the first sentence in
p aragraph (q)(1) and the first sentence in pa ragraph (q)(2) to read as follows:

§ 144.51 Conditions applicable to all permits.

* * * * *

(q) * * *

(1) The owner or operator of a Class I, II, III or VI well permitted under this
p art shall establish mechanical integrity prior to commencing injection or on a schedule determined by the Director. Therea fter the owner or operator of Class I, II, and III wells must maintain mech anical integrity as defined in § 146.8 and the owner or operator of Class VI well s must maintain mech anical integrity as defined in § 146.89 of this chapter. * * *

GWPC Recommendations: (q) * * *

(1) The owner or operator of a Class I, II, III or VI well permitted under this
p art shall establish mechanical integrity prior to commencing injection or on a schedule determined by the Director. Therea fter the owner or operator of Class I, II, and III wells must maintain mech anical integrity as defined in §146.8 and the owner or operator of Class VI we lls must maintain mechanical inte g rit y as Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24847defined in §146.89 of this chapter.

Rationale: EPA may want to reconsider the use of the term "or" as this implies that an initial MIT can be optional based on Dire ctors discretion which contradicts 146.89 with respect to Class VI wells. Alternatively, the two
p rovisions can be read together to require an initial MIT and to give the Director limited discretion to allow th e scheduling of the initial MIT after some injection has occurred, such as ma y be required during initial testing of the well and inj ection zone.

Response: EPA disagrees that the suggested edit is neede d, and clarifies that all owners or operators must demonstrate internal and exte rnal mechanical integrity prior to commencing injection as required at §146.87(a)(4).

Other EPA Comment Codes and Descriptions: 5900 2.14 Other administrative requirements under 40 CFR 144 Comment: Rule Provision: Part 146

EPA Proposal: 12. The authority citation for part 146 continues to read as follows:

Authority: Safe Drinking Water Act 42, U.S.C. 300f et seq.; Resource Conservation and Recovery Act, 42 U.S.C. 6901 et seq.

GWPC Recommendations: Support the proposed language.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment letter for further details. For additional information on EPA's final regulatory a pproach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost USDW Comment: Rule Provision: 146.5

EPA Proposal: 13. Section 146.5 is amended as follows:

a. Revising the first sentence in pa ragraph (e) introductory text; and

b. Adding paragraph (f).

(f) Class VI. Wells used for geologic sequestration of carbon dioxide beneath the lowermost formation containing an underground source of drinking water (USDW). Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24848

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24849GWPC Recommendations: (4) For enhanced re covery of oil or natural gas where geologic sequestration is occurring duri ng or in connection with enhanced recovery of oil or natural gas provided (i) there is reasonable expectation of more than insignificant future production vol umes or rates as a result of carbon dioxide injection and (ii) operating pr essures are no higher than reasonably necessary to produce such volumes or rates;

(f) Class VI. Wells inj ecting a carbon dioxide stream for geologic sequestration except those wells described in subsection (b)(4) of this section or otherwise excluded from this Class.

Rationale: There should not be a blanket prohibition c oncerning injection above USDW’s or at specific levels. The dete rmination of injection zones should be based upon appropriate containment. This is especially true in light of recent calls for changes in the definition of a US DW to include formations greater than 10K PPM TDS and the fact that several st ates including Wyoming and California might be prevented from instituting geol ogic sequestration as a practical matter if injection were limited to above USDW’s due to the great depth of some USDW’s. This would create a situation wher e otherwise good injection zones are artificially excluded, thus decreasing the overall availabili ty of geologic sequestration in the U.S.

The GWPC also recommends EPA consider retaining all geologic sequestration in oil and gas reservoirs under the jurisd iction of Class II UIC programs and create a subclass within this program for geologic storage of carbon dioxide. This subclass (Class II GS) would be used for those wells that depart from the traditional uses of Class II wells for enhanced recovery, and result in the application of Class VI standards. This change woul d eliminate any confusion over whether a Class II CO2 injection well us ed for enhanced recovery might also need a Class VI perm it and would avoid the need to change jurisdiction for a well from one state agency to another over time.

Response: Please see the response to the commenter’s suggested revision to §144.80.

Comment: Rule Provision: Part 146 Subpart H

EPA Proposal: 14. Subpart H is a dded to read as follows:

Subpart H - Criteria and Standards Applicable to Class VI Wells

Sec.

146.82 Required Class VI permit information. 146.83 Minimum criteria for siting. 146.84 Area of review a nd corrective action. 146.85 Financial responsibility. 146.86 Injection well construction requirements. 146.87 Lo gg in g , samplin g , and testin g prior to in j ection well operation. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24851GWPC Recommendations: Support the proposed language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Comment: EPA Proposal: (b) This subpart applies to wells used to inject carbon dioxide specifically for the purpose of geologi c sequestration, i.e., the long-term containment of a gaseous, liquid or supe rcritical carbon dioxide stream in subsurface geologic formations.

GWPC Recommendations: (b) This subpart a pplies to wells used to inject carbon dioxide streams into saline format ions for the purpose of geologic sequestration, i.e., the long-term containm ent of a carbon dioxide stream in subsurface geologic formations.

Rationale: Use of the term "specifically" was removed as it implied Class VI wells could not be used for multiple purposes and still be Class VI

Remove "gaseous, liquid or supercritical" as these term s are implied by the use of the term carbon dioxide.

See the rationale discussion under 146.85 regarding inclusion or exclusion of the term "saline"

Response: EPA disagrees with the suggested change. EPA believes that this paragraph, along with the definition of a CO2 stream at §146.81( d), appropriately convey the allo wable injection activities that may be permitted as Class VI. For additional inform ation on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 2060 1.5.3 Comments on grandfathering of existing wells (seeking comment) Comment: EPA Proposal: (c) This subpart applies to owners and operators of permit or rule-authorized Class I indus trial, Class II, or Class V experimental carbon dioxide injection projects who seek to apply for a Class VI geologic sequestration permit for their well or wells. If the Director determines that USDWs will not be endangered, such we lls are exempt, at the Director’s discretion, from the casing and cement ing requirements at §§ 146.86(b) and 146.87(a)(1) through (3).

GWPC Recommendations: (c) This subpart appl ies to owners and operators of permit or rule-authorized Class I industrial, Cl ass II, or Class V experimental carbon dioxide in j ection pro j ects who seek to appl y for a Class VI g eolo g ic Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24852

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24853sequestration permit for their well or wells or to convert to Class II GS operation. If the Director determines that USDWs will not be endangered, such wells are exempt, at the Director’s disc retion, from such Class VI requirements contained in this subpart as the Director specifies.

Rationale: The proposed EPA waiver appl ies only to the casing and cementing requirements. Directors shoul d have the flexibility to waive other requirements as appropriate for conversions to Class VI.

Response: EPA disagrees with commenters who suggest that other requi rements (outside of well construction) should also be grandfathered. Following re-permitting of the project as GS, many of the unique factors of GS sites (e.g., increased reservoir pr essures associated with large volumes of stored CO2 and the corrosivity of CO2 in the presence of wa ter) will result in an increased risk profile, warranting the specific requirements in the final GS rule. Therefore, fo llowing re-permitting as Class VI wells, these projects must be subject to the operational, MIT, monitoring, reporting, plugging, and postinjection site care and site closure requirements in the final GS rule. See the discussion of EPA's final regulatory approach in the preamble to the GS ru le for additional detail on these requirements.

Comment: Rule Provision: 146.82

EPA Proposal: Required Class VI permit information

This section sets forth the information wh ich the owner or operator must submit to the Director in order to be permitted as a Class VI well. The application for a permit for construction and operation of a Class VI well must include the following:

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Rule Provision: 146.82(a)

EPA Proposal: (a) Inform ation required in 40 CFR 144.31(e)(1) through (6);

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seekin g comment) Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24868

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24869Comment: EPA Proposal: (b) A map showing the inject ion well(s) for which a permit is sought and the applicable area of review . Within the area of review, the map must show the number, or name and loca tion of all injection wells, producing wells, abandoned wells, plugged wells or dry holes, deep stratigraphic boreholes, State or EPA a pproved subsurface cleanup sites, surface bodies of water, springs, mines (surface and subsu rface), quarries, water wells and other
p ertinent surface features including structures intended for human occupancy and roads. [Highlighted text: The map s hould also show faults, if known or suspected.] Only information of public reco rd is required to be included on this
map;

GWPC Recommendations: (b) A surface map showing the proposed locations for the injection well(s) for which a permit is sought and the applicable area of review. Within the area of review, the map must show the number, or name and location of all known injection wells, pr oducing wells, abandoned wells, plugged wells or dry holes, deep stratigraphi c boreholes, State or EPA approved subsurface cleanup sites, surf ace bodies of water, springs, mines (surface and subsurface), quarries, water wells and other pertinent surface features including structures intended for human occ upancy and roads. Only information of
p ublic record is required to be included on this map;

Rationale: Insert "known" before "injection"

Suggests removing highlighted text as faults are not shown on maps unless there is a surface expression of the fault. Al so, faults are detailed in (d) below and this language appears redundant.

Response: Regarding the comment that EPA delete ment ion of faults on surface maps, EPA believes that if faults have surface expressions, they should be presented on maps submitted; this information would complement the required cross section data. EP A is developing guidance on site characterization for GS projects to assist owners or operators and Directors in evaluating permit requirements and applications under §146.82. The guidance provides recommendations regardi ng characterizing the regional geology and hydrogeology of a proposed GS site as well as performing the necessary geochemical, geomechanical, and ge ophysical analyses of the injection and confining zone. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm. Please see the final rule and the discussion of geologic site ch aracterization in the preamble for additional information.

EPA acknowledges but did not make the suggested edits. EPA beli eves that all of the site characterization requirements at §146.82, including geomechanical information and geologic and topographic maps and cross sections, are essential to proper siti ng of a GS well and are the foundation for a detailed understanding of the local and regi onal geology, and that the owner or operator should collect this information, regardless of whether it is known in advance of the siting process. Collecting and evaluating this data supports impor tant evaluations regarding the suitab ility of the site to receive and contain injected CO2.

EPA acknowledges that some smaller fractures may not be detectable during the site characterization
p rocess, and clarifies that §146.82(a)(3 )(ii) requires the owner or opera tor to submit data on known or suspected faults and fr actures (i.e., not all fractures). Other re quirements for GS inje ction wells and sites can mitigate the potential impacts of unidentified fractures. These include li mitations on injection
p ressures to avoid propagation of existing fractures in the confini ng zone (§146.88(a)), collection andassessments of CO2 monitoring data at the site, and Ao R reevaluations (§146.84(e)) to assess possible CO2 movement through high-perm eability regions (i.e., faul ts and/or fractures) not detected in the initial site characterization.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: EPA Proposal: (c) The area of review ba sed on modeling, usi ng data obtained during logging and testing of the well and the formation as required by
p aragraphs (l), (r), and (s) of this section;

GWPC Recommendations: (c) A map delineating the area of review based upon modeling, using all available data includi ng data available from any logging and testing of wells within the area of review.

Rationale: Is this supposed to be a map, a tabular display, a cross section or series of cross sections etc... This appears to be related to a condition where a well is already drilled. This does not align with requesting information to receive a permit.

Response: EPA recognizes that information necessary for an area of review may not be available until after a well has been drilled and formation test ing can occur. EPA revise d §146.82 so that the final regulation specifies separate require ments for information to be submit ted with the permit application and before well construction is approved (at §146.82(a)) and information to be submitted before operation of the well is authorized (at §146.82(c)) in cluding The final area of review based on modeling, using data obtained during loggi ng and testing of the well a nd the formation §146.82(c)(1).

Based on its evaluation of all public comments and input on the proposed rule and NODA and Response to Comments EPA has made many revisions to the GS Rule. See the final rule and the site characterization discussion in the preamble fo r further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: EPA Proposal: (d) Information on the geologic structure and hydrogeologic
p roperties of the proposed storage site and overlying formations, including:

(1) Maps and cross sections of the area of review;

(2) Location, orientation, a nd properties of known or suspected faults and fractures that may transect the confini ng zone(s) in the area of review and a determination that they would not interfere with containment;

GWPC Recommendations: (d) Sufficient in formation on the geologic structure and reservoir properties of the proposed st orage site and overlying formations, includin g : Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24870

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24871(1) Isopach maps of the proposed injectio n and confining zone(s ), a structural contour map aligned with the top of the proposed injection zone, and at least two geologic cross sections of the area of review reasonably perpendicular to each other showing the geologic formati ons from the surface to total depth.

(2) Location, orientation, and properties of known or suspected subsurface faults that may transect the confining zone(s) in the area of review and a determination that they would not interfere with containment;

Rationale: Fractures can be incredibly sm all and it is virtua lly impossible to find all subsurface fractures. The GWPC also recommends addition of the term "Sufficient" before the information sought in (d) as this is more precise.

Response: EPA acknowledges that some sm aller fractures may not be detectable during the site characterization process, and clarifies that §146.82(a)(3)(ii) requi res the owner or operator to submit data on known or suspected faults and fractures (i.e ., not all fractures). Ot her requirements for GS injection wells and sites can mitigate the potential impacts of unidentified fractures. These include limitations on injection pr essures to avoid propagation of existi ng fractures in the confining zone (§146.88(a)), collection and assessments of CO2 monitoring data at the site, and Ao R reevaluations (§146.84(e)) to assess possible CO 2 movement through high-permeability regions (i.e., faults and/or fractures) not detected in the initial site characterization.

EPA disagrees with the other suggested edits because the GS rule, as written, affords flexibility to owners or operators and Directors to tailor the site characterization process to the unique features of the site. Please see the final rule and the discussion of geologic site characteri zation in the preamble for additional information.

Other EPA Comment Codes and Descriptions: 3130 2.1.3 Comments that operators should submit more (or different) geologic data than proposed ; 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: EPA Proposal: (3) Information on seismi c history including the presence and depth of seismic sources and a determin ation that the seismicity would not interfere with containment;

(4) Data on the depth, areal extent , thickness, mineralogy, porosity,
p ermeability and capillary pressure of the injection and confining zone(s); including geology/facies changes based on field data which may include geologic cores, outcrop data, seismic surveys, well logs, and names and lithologic descriptions;

(5) Geomechanical information on fracture s, stress, ductility, rock strength, and in situ fluid pressures within the confining zone; and

GWPC Recommendations: (3) Info rmation on seismic history that have affected the
p roposed area of review in cluding knowledge of previous seismic events and history of these events, including the pres ence and depth of se ismic sources and a determination that the seismicit y would not compromise containment; Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24872(4) Data sufficient to demonstrate the effectiveness of the injection and confining zone(s), including data on the depth, areal extent, thickness, mineralogy, porosity, vertical permeability reservoir pressure and of the injection and confining zone (s) within the area of review; including geologic changes based on field data which may include geologic core s, outcrop data, seismic surveys, well logs, capillary pr essure tests and names and lithologic descriptions;

(5) Geomechanical information on the confining zone(s) within the area of review; and

Rationale: Capillary pressure is too hard to measure outside the lab; how comparable are lab results to what goes into the ground. Sidewall core may not be sufficient to do this, and it is diffic ult to core the whole of the confining and injection zones. Rewording keeps the usefulness of capillary pressure in the
p rovision without making it a mandatory use.

Response: EPA acknowledges that laboratory methods are standard for dete rmining capillary pressures regardless of formation permeabilit y and that in situ measurements would require drilling of a well. However, EPA also anticipates that test wells will be drilled to suppor t geologic site characterization of the proposed GS sites and can be used to collect subsurface samples (for la boratory determination of capillary pressure) and take other necessary measur ements. EPA believes that information on capillary entry pressure is necessary and a ppropriate. Capillary entry pressure measurements on core samples can quantify the amount of buoyant force the confining zone can maintain before failure (World Resources Institute, 2008).

EPA recognizes that this information may not be available until after a well has been drilled. EPA revised §146.82 so that the final regulation specifie s separate requirements for information to be submitted with the permit applic ation and before well construc tion is approved (at §146.82(a)) and information to be submitted before operation of the well is authori zed (at §146.82(c)). Final information on injection zone pressures would be required following drilling of the well, at §146.82(c)(4).

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: EPA Proposal: (6) Geologic and topographic ma ps and cross sections illustrating regional geology, hydrogeology, and the geologi c structure of the local area.

GWPC Recommendations: Support the EPA language.

Response: EPA acknowledges the comment and the final rule retains the text as proposed.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: Rule Provision: 146.82(e) Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24873

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24874EPA Proposal: (e) A tabulati on of all wells within the area of review which
p enetrate the injection or confining z one(s). Such data must include a description of each well’s type, construction, date drilled, location, depth, record of plugging and/ or completion , and any additional information the Director may require;

GWPC Recommendations: (e) A compilation of all artificial pene trations within the area of review which penetrate the inje ction or confining zone(s). Such data must include a descriptio n of each well’s type, construction, date drilled, location, depth, record of plugging and/ or completion, and any additional information the Dire ctor may require;

Rationale: The GWPC felt that the term compilation was more appropriate than tabulation because tabulat ion as tabulation implies a spreadsheet while compilation can take numerous forms.

Response: EPA used the term tabulation in the final rule b ecause it is the same term used in the same requirement for other well classes; and, the regulated community and permitting officials are familiar with existing terminology.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Response to Comments EPA has made many revi sions to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: EPA Proposal: (f) Maps and stratigraphic cross sections indicating the general vertical and lateral limits of all USDW s, water wells and springs within the area of review, their positions relative to the injection zone(s) and the direction of water movement, where known;

GWPC Recommendations: (f) Ma ps and stratigra phic cross sections indicating the general vertical and lateral limits of all USDWs, the location of water wells and perennial springs within the area of review, their positions relative to the injection zone(s) and th e direction of water movement, where known;

Rationale: Clarification: Use of the term perennial befo re springs will prevent a requirement to list very minor, in termittent springs which are not hydrologically significant.

Response: EPA acknowledges the comment; however, the final rule does not reflect the suggested edit. The Agency uses the term “springs” in the site ch aracterization requirements fo r other classes of wells (see §146.70 (a)(2)) and the term is fa miliar to the regulat ed community and permitting officials. EPA adds that characterization will be site-specific, a nd owners or operators are encouraged to discuss the site with the Director as data are collected to identify thresholds for certain types of data.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Response Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24875to Comments EPA has made many revi sions to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 4710 2.7.1 Proposed submissions required for permit applications (seeking comment) Comment: EPA Proposal: (g) Baseline geochemical da ta on subsurface formations, including all USDWs in the area of review;

GWPC Recommendations: (g) Compilation of available baseline ge ochemical data on the proposed injection zone and nearest adjacent porous and permeable formation to the confining zone, existing utilized water supply aquifers and any other USDWs designated by the Director.

Rationale: It will be unduly burdensome to a ddress "all USDWs" in some contexts. This revision allows for more appropria te focusing on those USDWs designated by the Director.

Response: EPA believes that identifying and mapping all surrounding USDWs near an injection well, as specified at §146.82(a)(5), is necessary to ensure protection of all USDWs from endangerment. The
p urpose of the UIC requirements (including those for Class VI wells) is to ensure the protection of USDWs from endangerment, which ar e defined based on total dissolved solids (TDS) content, not their location or depth (40 CFR §144.3).

EPA adds that knowing the number, location and depth of USDWs near an injection well will generate baseline regional information, suppor t development of an effective testing and monitoring plan, and enhance owner or operator and Director understanding of the site. This requirement is common to all injection well classes.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Response to Comments EPA has made many revi sions to the GS Rule. See the fina l rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82); 4710 2.7.1 Propos ed submissions required for permit applications (seeking comment) Comment: EPA Proposal: (h) Proposed operating data:

(1) Average and maximum daily rate and volume of the carbon dioxide stream; (2) Average and maximum injection pressure; (3) The source of the carbon dioxide stream; and (4) An analysis of the chemical and physical characteristics of the carbon dioxide stream;

GWPC Recommendations: (h) Proposed operating data:

(1) Avera g e and maximum dail y in j ection rate and volume of the carbon dioxide Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24876

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24877stream; (2) Average and maximum surface injection pressure; (3) The source of the carbon dioxide stream; and (4) An analysis of the chemical and physical characteristics of the carbon dioxide stream;

Rationale: Clarification: Addition of the term surface in (h)(d) will make it clear as to where the injecti on pressure is to measured.

Rule Provision: 146.82(i)

EPA Proposal: (i) The compatibility of the carbon dioxide stream with fluids in the injection zone and minerals in both th e injection and the confining zone(s), based on the results of the formation te sting program, and with the materials used to construct the well;

(j) Proposed formation testing program to obt ain an analysis of the chemical and
p hysical characteristics of the injection zone and confining zone;

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

EPA Proposal: (k) Proposed stimulation program and a determination that stimulation will not interf ere with containment;

(l) The results of the formation testing pr ogram as required in paragraph (j) of this section;

(m) Proposed procedure to outline steps ne cessary to conduct injection operation;

(n) Schematic or other appropriate dr awings of the surface and subsurface construction detail s of the well;

(o) Injection well construction procedur es that meet the requirements of § 146.86;

GWPC Recommendations: (k) Proposed stimulation program and a de termination that stimulation will not compromise containment;

(l) The results of the formation testing pr ogram as required in paragraph (j) of this section;

(m) Proposed procedure to outline st eps necessary to conduct injection operation;

(n) A wellbore schematic of the subsur face construction details and surface wellhead construction.

(o) Injection well construction procedur es that meet the requirements of § 146.86;Rationale: "Interfere" is t oo ambiguous and should be re placed by "compromise" which limits concerns to situations where containment may be lost.

EPA Proposal: (p) Proposed area of review and corrective action plan that meets the requirements under § 146.84;

(q) The status of corrective action on wells in the area of review;

(r) All available logging and testing pr ogram data on the well required by § 146.87;

(s) A demonstration of mechanical integrity pursuant to § 146.89;

(t) A demonstration, satisfactory to the Director, that the applicant has met the financial responsibility requirements under § 146.85;

GWPC Recommendations: (p) Proposed corr ective action plan for artificial
p enetrations within the area of review, if necessary

(q) All available logging and testing program data on the well required by § 146.87;

(r) The proposed demonstration method fo r mechanical integrity pursuant to

(s) A demonstration, satisfactory to the Director, that the applicant has met the financial responsibility requirements under § 146.85;

Rationale: (q) Should be deleted because it is not part of an application
p rocess but, rather a post permitting activ ity. This would result in a renumbering of the subsections after the new (q).

Rule Provision: 146.82(u)

EPA Proposal: (u) Proposed testing a nd monitoring plan required by § 146.90;

(v) Proposed injection well plugging plan required by § 146.92(b);

(w) Proposed post-injection site care and site closure pl an required by § 146.93(a);

(x) Proposed emergency and remedial response plan required by § 146.94; and

(y) Any other information requested by the Director.

GWPC Recommendations: (t) Proposed test ing and monitoring plan required by § 146.90;

(u) Proposed injection and monitoring well(s) plugging plan required by § 146.92(b);(v) Proposed post-injection site care and site closure plan required by § 146.93(a);

(w) Proposed emergency and remedial response plan required by § 146.94; and

(x) Any other information requested by the Director.

Rationale: Need to address the plugging of monitoring well(s), if any, included in the project.

Response: EPA acknowledges the commenter’ s support for portions of the subject requirements. EPA disagrees that the technical clarif ications suggested are necessary. EPA adds that it is developing guidance for owners or operators on the geologic si te characterization and AoR and corrective action
p rocesses. These guidances will provide recommendations and clarify the intent of all required elements of a permit application. The guidan ces can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: Rule Provision: 146.83

EPA Proposal: Minimum criteria for siting

(a) Owners or operators of Class VI wells must demonstrate to the satisfaction of the Director that the wells will be sited in areas with a suitable geologic system. The geologic system must be comprised of:

(1) An injection zone of sufficient areal extent, thickness, porosity, and
p ermeability to receive the total anti cipated volume of the carbon dioxide stream;

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment and the final rule retains the text at §146.83(a) as proposed.

Other EPA Comment Codes and Descriptions: 3110 2.1.1 Proposed siting requirements (i.e., injection/confining zones, trapping mechanism) Comment: EPA Proposal: (2) A confining zone(s) that is free of transmissive faults or fractures and of sufficient areal extent and integrity to contain the injected carbon dioxide stream and displaced format ion fluids and allow injection at
p roposed maximum pressures and volume s without initiati ng or propagating fractures in the confining zone(s); and Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24878

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24879GWPC Recommendations: (2) A confining zone (s) that is laterally continuous and free of known transecting, transmissive faults or fractures over an area sufficient to prevent the moveme nt of fluids into a USDW;

Rationale: Suggest using the Class I regulation for this paragraph (2) in 146.62(c) with the addition of reactivation of existing faults or fractures and before the terms faults or fractur es the word known should be added.

Response: The Agency believes that the requirement at §146.83(a)(2) that the confining zone to be free of transmissive faults or fractur es is appropriate for Class VI wells and is necessary to ensure containment of the injectate and that requiring the confining zone to be free of transmissive faults maximizes protection of USDWs from endangerment. EPA believes that the text regarding propagation of faults and fractures is important to avoid the potential for fluid move ment and to ensure that injection is at appropriate pressures. Class I hazardous waste injection well operators must also meet a similar requirement that the site is free of transmissive faults or fractures; they have successfully made such demonstrations in the past. While core samples obt ained through drilling and hydr aulic testing are direct methods to obtain such informati on, geophysical techniques such as seismic or electromagnetic surveys can also be used in many geologic settings to demonstrate the absence of or identify and characterize the
p resence of faults or fractures. EPA adds that the Di rector will evaluate all geologic data on the site to ensure protection of USDWs from endangerment before approving a site for a GS project.

Other EPA Comment Codes and Descriptions: 3120 2.1.2 Need to identify additional confining and containment zones (seeking comment) Comment: EPA Proposal: (b) At the Director’s discre tion, owners or operators of Class VI wells must identify and characterize additional zones that will impede vertical fluid movement, are free of faults a nd fractures that may interfere with containment, allow for pressure dissipation, and provide additional opportunities for monitoring, mi tigation and remediation.

GWPC Recommendations: Delete paragraph

Rationale: This paragraph creates a pres umption that additional zones WILL be required. It is also redundant from previous sections.

Response: EPA clarifies that secondary confining zones are not require d for all GS sites. Rather, secondary confining zones are required when the Director determines that these zones are needed to maximize the protection of USDW s from endangerment. EPA retains the requirement to identify additional containment/confining zones, if required by the Director, as proposed (e.g., §146.83(b)). EPA believes that, in some situations, the presence of additional confining and c ontainment zones above the
p rimary (i.e., lowermost) confining zone can improve USDW pr otection. These laye rs could further impede vertical fluid movement a nd allow for pressure dissipation, and also provide additional sites for monitoring, mitigation, and remediation.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24880

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24881Comment: Rule Provision: 146.84

EPA Proposal: 146.84. Area of revi ew and corrective action

(a) The area of review is the region surrounding the geologic sequestration
p roject that may be impacted by the injection activity. The area of review is based on computational modeling that acc ounts for the physical and chemical
p roperties of all phases of the in jected carbon dioxide stream.

GWPC Recommendations: (a) The area of re view is based on computational modeling that accounts for the physical and chemi cal properties of all phases of the injected carbon dioxide stream.

Rationale: This is the same as the defi nition of "Area of review" that was revised by the GWPC .to delete the first sentence.

Comments on many provisions are predicated on proposed changes in definitions

Response: The Agency has carefully considered all co mments on the AoR definition at 146.84(a) and modified it to read as follow s: The region surrounding the geologic sequestration project where USDWs may be endangered by the injection activity. The ar ea of review is delineat ed using computational modeling that accounts for the physical and chemical properties of all pha ses of the injected CO2 stream and is based on available site characteri zation, monitoring, and operational data.

Other EPA Comment Codes and Descriptions: 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: EPA Proposal: (b) The owner or operator of a Class VI well must prepare, maintain, and comply with a plan to deli neate the area of review for a proposed geologic sequestration project , periodically reevaluate the delineation, and
p erform corrective action that meets the requirements of this section and is acceptable to the Director. As a part of the permit application for approval by the Director, the owner or operator must s ubmit an area of revi ew and corrective action plan that includes the following information:

(1) The method for delineating the area of review that meets the requirements of
p aragraph (c) of this section, including the model to be used, assumptions that will be made, and the site characterization data on which the model will be based;

GWPC Recommendations: (b) The owner or opera tor of a Class VI well must prepare, maintain, and comply with a plan to deli neate the area of review for a proposed geologic sequestration project, reevalua te the delineation, and perform corrective action that meets the requirements of this s ection in a manner and at a frequency acceptable to the Director. As a part of the permit application, the owner or operator must submit an area of review and corrective action plan that includes the followi ng information:

Rationale: Su gg est deletion of "periodicall y ." See Work g roup recommendation 7.6 Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24882from

Recommendations for the Regulatory Management of Geologic Sequestration of CO2 Under the UIC Program

Replace with "in a manner and at a frequency"

Delete "for approval by the Director,". Director’s approval is implicit in a
p ermit application.

Response: EPA disagrees with the suggested change, a nd is retaining the approach of setting a minimum fixed frequency for reevaluating the AoR but has, based on commenters' input, changed the frequency from 10 years to at least every 5 year s, as specified in §146.84(e). EPA agrees with commenters that site-specific information is an im portant factor in deter mining an appropriate AoR reevaluation frequency, and adds that the owner or operator's AoR and corrective action plan must describe the minimum fixed frequency for reeval uating the AoR and the site-specific conditions on which this frequency is based. EPA adds that the Dire ctor will evaluate the proposed plan in connection with a review of a vast amount of geologic and proposed operating da ta in determining whether to approve the plan. EPA is developing guidance describi ng approaches to preparing all of the required GS
p roject plans, which will address considerations for determining an appropriate AoR reevaluation schedule. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment); 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: Rule Provision: 146.84(b)(2)

EPA Proposal: (2) A description of:

(i) The minimum fixed frequency, not to exceed 10 years, the owner or operator
p roposes to reevaluate the area of review;

(ii) The monitoring and operational conditions that woul d warrant a reevaluation of the area of review prior to the next scheduled reevaluation as determined by the minimum fixed frequency established in paragraph (b)(2)(i) of this section.

(iii) How monitoring and operational data (e.g., injection rate and pressure) will be used to inform an area of review reevaluation; and

GWPC Recommendations: Delete (i) and (ii)

Rationale: Suggest deletion of (i) as th is is handled by "manner and at a frequency acceptable to the Director in (b)

Suggest deletion of (ii) for sa me reason as comment on (i)

Response: EPA believes that periodic AoR reevaluation at a set frequency of at least every 5 years is

necessar y to ensure protection of USDWs from endan g erment and address the un certainties inherent in Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24883p redictive modeling. Periodic AoR reevaluations at §146.84(e) ensure that a deliberate effort is made to verify, based on monitoring and operational data, that the CO2 plume is moving within the subsurface as
p redicted. EPA believes that less frequent reevaluations may not be su fficient to appropriately model
p lume and pressure front movement , establish conditions for corrective action, and ensure protection of USDWs from endangerment.

EPA clarifies that if site monitoring data agrees with the existing AoR delineation, a model recalibration may not be necessary, and the AoR reevaluation may consist of a demonstration that the current AoR delineation is adequate base d on site monitoring data.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: EPA Proposal: (iv) How corrective action will be conducted to meet the requirements of paragraph (d) of this section, including what corrective action will be performed prior to injection a nd what, if any, portions of the area of review will have corrective action addressed on a phased basis and how the
p hasing will be determined; how corrective action will be adjusted if there are changes in the area of review; and how site access will be guaranteed for future corrective action.

GWPC Recommendations: (iv) How corrective action will be conducted to meet the requirements of paragraph (d) of this section, including what corrective action will be performed prior to injection a nd what, if any, portions of the area of review will have corrective action addressed on a phased basis and how the
p hasing will be determined; how corrective action will be adjusted if there are changes in the area of review; and how si te access will be assured for future corrective action.

Rationale: Replace "guaranteed" with "assured" Future access cannot be absolutely guaranteed for an area in adva nce that may not even be within the boundaries of the AOR/ project. However, as surance of access is a standard that is less onerous than guaran teed, it is firmer than another standard such as "arranged"

Response: EPA is retaining this requirement as pr oposed. The purpose of the corrective action requirement at §146.84(d) is to ensure that all wells in the AoR that have the potential to cause the movement of CO2 or other fluids into or betw een USDWs receive appropriate corrective action. In general, to meet this re quirement, the owner or operator will most likely need to obtain the right of access to wells that may re quire corrective action, and demonstrate they have done this in their proposed AoR and corrective action plan. In the AoR and co rrective action plan, the owner or operator must describe how site access will be guaranteed for future corrective action, as specified in §146.84(b)(2) (iv).

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(c) Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24884

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24885(c) Owners or operators of Class VI wells must perform the following actions to delineate the area of review, identify al l wells that require corrective action, and perform corrective action on those wells:

(1) Predict, using computational modeli ng, the projected lateral and vertical migration of the carbon dioxide plume and formation fluids in the subsurface from the commencement of in jection activities until th e plume movement ceases,
p ressure differentials sufficient to cause the movement of injected fluids or formation fluids into a USDW are no longer present, or after a fixed time period as determined by the Director. The model must:

GWPC Recommendations: (c) Owners or operators of Class VI wells must perform the following actions to delineate the area of review, identify all wells that require corrective action, and perform corrective action on those wells:

(1) Predict, using computational modeli ng, the projected lateral and vertical migration of the carbon dioxide plume and formation fluids in the subsurface from the commencement of in jection activities until th e plume movement ceases,
p ressure differentials sufficient to cause the movement of injected fluids or formation fluids into a USDW are no longer present, or for a fixed time period as determined by the Director. The model must:

Rationale: Should say "for" not "after."

Response: Based on its evaluation of all public commen ts and input on the proposed rule, EPA has clarified this language in the final rule. It now reads, “Predict, using exis ting site characterization, monitoring and operational data, a nd computational modeling, the pr ojected lateral and vertical migration of the carbon dioxide plum e and formation fluids in the s ubsurface from the commencement of injection activities until the pl ume movement ceases, until pressure differentials sufficient to cause the movement of injected fluids or formation fluids into a USDW are no longer present, or until the end of a fixed time period as de termined by the Director.”

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(c)(i)

EPA Proposal: (i) Be based on detailed ge ologic data collected to characterize the injection zone, confining zone and any additional zones; and anticipated operating data, including injection pressures, rates and total volumes over the
p roposed life of the geolog ical sequestration project;

(ii) Take into account any geologic heterogeneities, data quality, and their
p ossible impact on model predictions; and

(iii) Consider potential migration thr ough faults, fractures, and artificial
p enetrations. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24886GWPC Recommendations: (i) Be based on de tailed geologic data collected to characterize the injection zone, confini ng zone; and anticipated operating data, including injection pressures, rates a nd total volumes over the duration of injection;

(ii) Take into account relevant geologic heterogeneities, and data quality, and their possible impact on model predictions; and

(iii) Consider potential migration thr ough faults, fractures, and artificial
p enetrations.

Rationale: Suggest deletion of "any addi tional zones". You do not need to include any additional zone s if you use the current CFR definition of confining zone since it includes multiple zones.

Should be geologic not geological for cons istency with other provisions because geologic sequestration pr oject is defined.

Suggest "duration of injection" instead of "life of the geological sequestration
p roject"

Suggest "relevant" instead of any in (ii)

Insert "and" between "heter ogeneities" and "data"

Response: EPA agrees that detailed geologic data is i nvaluable to modeling an accurate AoR. The Agency believes that the AoR delineation requireme nts in 146.84 (c)(1)(i), whic h specify using "detailed geologic data collected to characte rize the injection zone, confining zone and any additional zones; and anticipated operating data...," and (c)( iii) to "consider potential migration through faults, fractures and artificial penetrations," provide the necessary information needed for appropriate site modeling, subsequent site evaluation, and protection of USDW s from endangerment. EPA adds that the extensive requirements for data that is to be included in the permit application at 146.82 incorporate these same types of information. The Director will review the AoR models in the context of the extensive site data submitted with the permit applica tion. EPA recognizes that in some in stances, the Direct or may require additional types of data to be in cluded in the AoR delin eation (146.84(c)(1)). Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS Rule. See the final rule and preamble for further discussion on EPA's final approach.

EPA disagrees that only the injection and confini ng zones should be included in AoR modeling of GS sites. EPA believes that the modeling should also take into account the possibility of displaced fluids or brines caused by a lateral and/or ve rtical pressure plume, and theref ore it may be necessary to include additional zones along with the confin ing/injection zones to ensure the integrity of the confining zone and ultimately protect a US DW from endangerment.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: EPA Proposal: (2) Using methods approve d by the Director, identify all
p enetrations, includin g active and abandoned wells and under g round mines, in the Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24887area of review that may pe netrate the confining zone. Provide a description of each well’s type, construction, date drilled, location, depth, record of
p lugging and/or completion, and any additi onal information the Director may require; and

GWPC Recommendations: (2) Using methods approved by the Director, identify all known artificial penetrations into th e confining zone, including active and abandoned wells and underground mines, in th e area of review that may penetrate the confining zone. Provide a description of each well’s type, construction, date drilled, location, depth, record of plugging and/or completion, and any additional information the Di rector may require; and

Rationale: Insert "known artificial pe netrations into the confining zone"

EPA Proposal: (3) Determine which abandone d wells in the area of review have been plugged (as required by § 146.92) in a ma nner that prevents the movement of carbon dioxide or associated flui ds that may endanger USDWs

GWPC Recommendations: (3) Determine wh ich abandoned wells identified in 146.84 (c) (2) have been plugged (as required by §146.92) in a manner that prevents the movement of carbon dioxide or displaced formation fluids that may endanger USDWs.

Rationale: Add identified in 146.84 (c) (2)

Remove "area of review" as redundant.

Suggest change "associated fluids" to "dis placed formation fluids." Associated fluids is not defined so if EPA means displaced formation fluids the regulation should just use this term. Otherwise, you need to define associated fluids.

Response: EPA is retaining the requirement in 146.84(c)(2 ) as proposed. EPA agrees with commenters that, for most GS sites, relying on database and other public records searches (i.e., of "known" artificial
p enetrations) will be sufficient to meet the requirements at §146.84(c)(2). However, the Agency recognizes that there may be situations where addi tional surveys or research to locate wells may be appropriate. For example, there may be cases where the Director may determine that ground or airborne surveys for wells are appropriate, e.g., if there is reason to believe, based on knowledge of the site or of available data, that the incomp leteness of information on known wells could compromise USDW
p rotection from endangerment. In order to preserve the Director's discretion to require an operator to supplement a records search, EPA di d not make the suggested change.

EPA clarifies that the term "associ ated fluids" as proposed in §146.84(c)(3) refers to formation fluids, other injectates, etc that may be present in the subs urface and affect movement of the CO2 plume and/or
p ressure front. EPA believes this te rminology would incorporate any fluids in the subsurface that could
p otentially move through artificial penetrations and aff ect USDWs. EPA has revised the language at §146.84(c)(3) to read, "... carbon dioxide or ot her fluids that may endanger USDWs..."

Other EPA Comment Codes and Descriptions: 3460 2.2.2.3 Acceptable correct ive action techniques Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24888for GS sites (e.g., cements) Comment: Rule Provision: 146.84(d)

EPA Proposal: (d) Owners or operators of Class VI wells must perform corrective action on all wells in the area of review that are determined to need corrective action using methods necessary to prevent th e movement of fluid into or between USDWs including use of corrosion resistant materials, where appropriate.

GWPC Recommendations: (d) Owners or operators of Class VI wells must perform corrective action using materials suitable for use with carbon dioxide streams, on all wells identified in 146.84(c)(2) that are determined to need corrective action".

Rationale: Re-write as follows "Owners or operators of Class VI wells must
p erform corrective action using corrosion resistant materials, when appropriate, on all wells identified in 146.84(c)(2) that are determined to need corrective action".

Response: EPA revised the text at §146.84(d) to require the use of materials that are "compatible with the carbon dioxide stream." EPA beli eves this language change addresses commenters' concerns and is also consistent with other language regardi ng materials requirements in the GS rule.

Other EPA Comment Codes and Descriptions: 3400 2.2.2 Corrective Action Comment: EPA Proposal: (e) If monitoring data indi cate an endangerment to USDWs, the owner or operator must notify the Director and cease operations as required by § 146.94.

GWPC Recommendations: Delete

Rationale: Why is this needed if 146.94 al ready specifies the notification and cessation of injection?

Response: Based on consideration of all public comments and other information, EPA deleted this
p rovision from §146.84. The final rule now contains a provision in §146.91(c) that requires the owner or operator to report within 24 hours any evidence that th e carbon dioxide stream or associated pressure front may cause an endangerment to a USDW. EPA believes this change consolidates reporting requirements in one place and provides additional clarity.

Other EPA Comment Codes and Descriptions: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) Comment: EPA Proposal: (f) At the minimum fixed fr equency, not to exceed 10 years, as specified in the area of review and corr ective action plan, or when monitoring and operational conditions warrant, owners or operators must:

(1) Reevaluate the area of review in the same manner specified in para g raph (c) Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24889

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24890(1) of this section;

(2) Identify all wells in the reevaluated area of review that require corrective action in the same manner specified in paragraph (c)(2) of this section;

GWPC Recommendations: (f) As specified in the approved area of review and corrective action plan, or when monito ring and operational conditions warrant, owners or operators must

(1) Reevaluate the area of review in the same manner specified in paragraph (c) (1) of this section;

(2) Identify all wells in the reevaluated area of review that require corrective action in the same manner specified in paragraph (c)(2) of this section;

Rationale: Delete "At the minimum fixed frequency, not to exceed 10 years".

Insert "approved" before "a rea of review" in (f).

Response: EPA disagrees with the suggested edit, and beli eves that periodic AoR reevaluation at a set frequency is necessary to ensure protection of USDWs from endangerment and address the uncertainties inherent in predictive mo deling. Periodic AoR reevaluations at §146.84(e ) ensure that a deliberate effort is made to verify, based on monitoring and operationa l data, that the CO2 plume is moving within the subsurface as predicted. EPA believes that less frequent reevaluations may not be sufficient to appropriately model plume and pre ssure front movement, establish c onditions for corrective action, and ensure protection of USDWs from endangerment.

EPA clarifies that if site monitoring data agrees with the existing AoR delineation, a model recalibration may not be necessary, and the AoR reevaluation may consist of a demonstration that the current AoR delineation is adequate base d on site monitoring data.

Other EPA Comment Codes and Descriptions: 3700 2.2.5 Comments on the requirement for an AoR and corrective action plan Comment: EPA Proposal:(3) Perform corrective acti on on wells requiring corrective action in the reevaluated area of review in th e same manner specified in paragraph (c) (3) of this section; and

(4) Submit an amended area of review and corrective action plan or demonstrate to the Director through monitoring data and modeling results that no amendment to the area of review and corr ective action plan is needed.

GWPC Recommendations: (3) Perform co rrective action on wells requiring corrective action in the reevaluated area of review in the same manner specified in paragraph (c)(3) of this section; and

(4) Submit an amended area of review and corrective action plan or demonstrate to the Director through monitoring data a nd modeling results that no change to the area of review and corr ective action plan is needed. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24891Rationale: Suggest "change" instead of "amendment" in (4) because the term amendment is typically cons trued to mean an offici al permit modification
p rocess.

Response: EPA disagrees with the suggested change re garding the term “amendment.” EPA believes that, in some cases an amendment to the AoR and corrective action plan may warrant a permit modification. EPA added text to §144.39(a)(5) that permit modifications, requiring public notice and comment, are required if the Director determines that a modification is necessary based on an AoR reevaluation, amendments to any of th e project plans, or a review of the testing and monitoring results. EPA made this change because the Agency recognizes that the AoR reevaluation process and any subsequent modifications to the plans may gene rate significant levels of public interest.

EPA clarifies that if site monitoring data agrees with the existing AoR delineation, a model recalibration may not be necessary, and the AoR reevaluation may consist of a demonstration that the current AoR delineation is adequate base d on site monitoring data.

Other EPA Comment Codes and Descriptions: 3300 2.2.1 Delineating the AoR/Modeling CO2
movement Comment: Rule Provision: 146.84(g)

(g) The emergency and remedial respons e plan (as required by § 146.94) and a demonstration of financial responsibil ity (as described by § 146.85) must account for the entire area of review, re gardless of whether or not corrective action in the area of review is phased.

GWPC Recommendations: (g) The emergency and remedial response plan (as required by § 146.94) and a demonstration of financial responsibility (as described by § 146.85) must account for the enti re area of review [as modified], regardless of whether or not corrective action in the area of review is phased.

Rationale: Need to add phrase to account for the periodic reevaluations and
p ossible revisions that will be occurri ng. Addition of the term [as modified] addresses this concern.

Response: EPA agrees with the commenter and has modifi ed the final rule at §146.84(f) to require the owner or operator to periodically review the emergenc y and remedial response plan to take into account the most recent AoR. Owners or operators must also periodically update the de monstration of financial responsibility to account for any such changes.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Rule Provision: 146.85

EPA Proposal: 146.85 Financial responsibilit y Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24892

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24893(a) The owner or operator mu st demonstrate and maintain financial responsibility and resources for corrective action (t hat meets the requirements of § 146.84), injection well plugging (that meets the requirements of § 146.92), postinjection site care and si te closure (that meets the requirements of § 146.93), and emergency and remedial response (tha t meets the requirements of§ 146.94) in a manner prescribed by the Director until:

(1) The Director receives and approves th e completed post-injection site care and site closure plan; and

(2) The Director determines that the site has reached the end of the postinjection site care period.

GWPC Recommendations: No specific language recommended. See rationale

Rationale: Maintenance of plugging liability until site closure release by the Director is probably not needed once th e well has been plugged. Should the owner/ operator be allowed to make a de monstration to the Director for the
p artial release of other financ ial responsibility elements?

Response: EPA will allow owners or operators to use se parate or multiple fi nancial responsibility instruments for different GS activities. However, owners or operators must demonstrate adequate financial responsibility for all required activities, including well plugging, with their permit application,
p er §146.82(a)(14). In addition, on an annual basis, the owner or operator must adjust the cost estimate for inflation, increase or decrease the value of the fi nancial instrument to match the cost estimate, and
p rovide any updated informat ion related to their financial responsib ility instrument(s), or at any other time deemed appropriate by the Director. These annual reviews provide a mechanism for revising cost estimates up or down to account for changes in the project, including the exec ution of environmental obligations as phases of a GS project are completed. See the final rule and preamble for further discussion of EPA's final approach to financial responsibility.

Regarding the suggested edit at §146.85(a)(1), EPA clar ifies that the owner or operator may be released from a financial instrument when the phase of th e project for which the instrument was required is complete and financial obligations for the required activity have been met, as specified in §146.85(b)(2).

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: EPA Proposal: (b) The owner or operator must provide to the Director, at a frequency determined by the Director, written updates of adjustments to the cost estimate to account for any amendments to the area of review and corrective action plan (§ 146.84), the injection we ll plugging plan (§ 146.92), and the
p ost-injection site care and si te closure plan (§ 146.93).

GWPC Recommendations: (b) The owner or opera tor must provide to the Director, at a frequency determined by the Director, but no more frequently than annually, written updates or adjustments to the cost estimate to account for any changes to: the area of review and corrective action plan (§146.84), the in j ection well Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24894p lugging plan (§146.92), and the post-injection site care and site closure plan (§146.93).

Rationale: Does this contemplate bot h upward and downward adjustments?

Suggest "change" instead of amendments.

Clarification on what is meant by "updates or adjustments" woul d be beneficial e.g. what is included, at what frequency etc...

Response: Owners or operators will be required to adju st costs when they are no longer adequate, as specified in the GS rule, at §146.85. These baseline estimates can then be updated annually and kept current through input from ongoing dialogue between th e owner or operator and the Director. The cost estimation methodology guidance will also contain inst ructions on how to adju st cost estimates for inflation to help account for the long-term nature of GS and will address the need to adjust cost estimates for inflation.

EPA is developing guidance on financial responsibility for GS wells. The guidance will include a discussion on how to estimate costs to assist GS well owners or ope rators, third party insurers or
p roviders of financial instrument s, and permitting authorities in developing estimates of the costs associated with various GS activities. Th e guidance is available on EPA's website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

EPA did not make the proposed edits, but did extensiv ely revise and clarify th e financial responsibility requirements. See the final GS rule and preamble for additional information on EPA's final approach.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Rule Provision: 146.85(c)

EPA Proposal: (c) The owner or operator must notify th e Director of adverse financial conditions such as bankruptcy that may affect the ability to carry out injection well plugging an d post-injection site car e and site closure.

GWPC Recommendations: (c) The owner or operator must notify the Director of adverse financial conditions that may affect the ability to ca rry out injection well plugging and post-injection si te care and site closure.

Rationale: Delete "such as bankruptcy" fr om (c). Such examples of potential circumstances are unnecessary.

Response: EPA did not make the proposed edits, but did extensively revise and clarify the financial responsibility requirements. EPA believes that the Director must be notified of bankruptcy specifically, among other adverse financial conditions , because it affects the use of fi nancial instrument. See the final GS rule and preamble for additiona l information on EPA's final appro ach. Please see the final rule and the discussion of financial responsibility in the preamble for additional information. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24895Other EPA Comment Codes and Descriptions: 5432 2.9.1.1 Need to adjust financial responsibility mechanisms (seeking comment) Comment: EPA Proposal: (d) The operator must provide an adjustment of the cost estimate to the Director if the Di rector has reason to believe that the original demonstration is no longer ad equate to cover the cost of injection well plugging (as required by § 146.92) and post-injecti on site care and site closure (as required by § 146.93).

GWPC Recommendations: (d) The operator must provide an adjustment of the cost estimate to the Director if the Director has reason to believe that the most recent demonstration is no longer adequate to cover the cost of injection well
p lugging (as required by § 146.92) and post-injection site care and site closure (as required by § 146.93).

Rationale: The reference should be to the last demonstration not the original demonstration

This is a one time extraordinary ev ent. Regular updates are covered by 146.85(b).

Recognize that these will be updated periodically.

Response: EPA agrees that it is important to periodical ly update cost estimate s that support financial responsibility determinations. EP A clarifies that the GS rule, at §146.85(e) requires the owner or operator to provide annual updates to the cost estima te to account for any amendments to the AoR and corrective action plan, the injection well pluggi ng plan, and the PISC an d site clos ure plan.

Other EPA Comment Codes and Descriptions: 3800 2.3 Proposed Injection Well Construction Requirements ( 40 CFR 146.86) Comment: Rule Provision: 146.86

EPA Proposal: 6. Injection well construction requirements

(a) General. The owner or operator must ensure that all Class VI wells are constructed and completed to:

(1) Prevent the movement of fluids in to or between USDWs or into any unauthorized zones; (2) Permit the use of appropriate test ing devices and workover tools; and (3) Permit continuous monitoring of the annulus space between the injection tubing and long string casing.

GWPC Recommendations: (a) General. The owne r or operator must ensure that all Class VI wells are constructed and completed to:

(1) Prevent the movement of fluid containin g an y contaminant into USDWs per 40 Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24896

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24897CFR Part 144.12(a). (2) Permit the use of appropriate test ing devices and workover tools; and (3) Permit continuous monitoring of the annulus space between the injection tubing and long string casing.

Rationale: Mirror language concerning endangerment standard in (1).

The GWPC suggests re-wording (a)(1) to simp lify and make it consistent with the CFR definitions of fluid movement.

Response: EPA believes that protecti on of USDWs from endangerment and prevention of fluid movement between formations is paramount and believes that the language as proposed meets the nonendangerment standard provided in SDWA and §144.12. Appropriately designed and constructed wells are necessary to prevent endangerment to USDWs and maintain integrity of the well throughout the lifetime of a GS pr oject. This is the foundation of the requi rements for construction and pre-operational testing of Class VI wells at §§146.86 and 146.87.

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revi sions to the GS rule. Please see the final rule and preamble for additional information.

Other EPA Comment Codes and Descriptions: 3860 2.3.3 Well component degradation Comment: EPA Proposal: (b) Casing and Ceme nting of Class VI Wells.

(1) Casing and cement or othe r materials used in the construction of each Class VI well must have sufficient structural strength and be designed for the life of the geologic sequestration proj ect. All well materials must be compatible with fluids with which the materials may be exp ected to come into contact and meet or exceed standards developed for such materials by the American Petroleum Institute, ASTM International, or comparable standards acceptable to the Director. The casing and cementing program must be designed to prevent the movement of fluids into or between USDW s. In order to allow the Director to determine and specify casing and cementing requirements, the owner or operator must provide the following information:

GWPC Recommendations: (1) Casing and ceme nt or other materials used in the construction of each Class VI well must have sufficient structural strength and be designed for the life of the operating life of the well. All well materials must be compatible with fluids with whic h the materials may be expected to come into contact and meet or ex ceed test standards or pract ices developed for such materials by the American Petroleum Institut e, ASTM International, or comparable standards acceptable to the Director. The casing and cementing program must be designed to prevent the movement of fluids into or between USDWs. In order to allow the Director to determine and sp ecify casing and cementing requirements, the owner or operator must provide the following information:

Rationale: Suggest substituting "operating li fe of the well" for "the life of the g eolo g ic sequestration pro j ect" in (1) The GWPC determined that g eolo g ic Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24898sequestration project was a nebulous term th at could not be calculated and thus would have no meaning in designing a casing or cementing program.

IMirror the non endangerment standard.

Response: EPA disagrees that the casing, cement or other materials should only be designed for the
p eriod of the injection process, ra ther than the life of the seques tration project. GS projects are anticipated to have long life spans in comparison to other types of deep injection wells. Not only must Class VI wells be able to function sa fely and properly over the lifespan of the GS project, but they must b e constructed such that USDWs remain protecte d after well plugging. The requirements at §146.86 will ensure that the well can maintain integrity thr oughout the proposed life span of the project, including after the injection well is plugged and through post-injection site care period and beyond. While the risk
p rofile of a GS site will decrease following cessation of injection, EPA believes that Class VI wells must be designed to protect USDWs from endangerment for the life of the project. Furthermore, rigorous casing and cementing help ensure th at the Class VI well will not se rve as a conduit for movement of fluids associated with future injection operations.

Other EPA Comment Codes and Descriptions: 3860 2.3.3 Well component degradation Comment: Rule Provision: 146.86(b)(1)

EPA Proposal: (i) Depth to the injection zone; (ii) Injection pressure, external pressure , internal pressure and axial loading; (iii) Hole size; (iv) Size and grade of all casing strings (wall thickness, ex ternal diameter, nominal weight, length, joint specific ation and construction material); (v) Corrosiveness of the carbon dioxi de stream, and formation fluids; (vi) Down-hole temperatures; (vii) Lithology of injecti on and confining zones;

GWPC Recommendations: (i) Dept h to the injection zone;

(iii) Hole size; (iv) Size and grade of all casing strings (wall thickness, ex ternal diameter, nominal weight, length, joint specific ation and construction material); (v) Predicted corrosiveness of the combin ed carbon dioxide stream and formation fluids; (vi) Down-hole temperatures and pressures; (vii) Lithology of injecti on and confining zones;

Rationale: What is meant by external and internal pressure? Recommend deleting (ii).

Insert "and pressures" in (vi)

Cannot measure the corrosiveness of the CO2 stream because it is not corrosive. Only liquids will yield pH measurements.

Response: EPA disa g rees with the su gg ested edits. The internal and external pressure mentioned in Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24899§146.86(b)(1)(ii) refers to pressure on the well casing . Internal pressures coul d be caused by cement or annular fluids; external pressures could be caused by cementing against the borehole or pressure head from formations.

At §146.86(c)(3)(ii), EPA clarifies that, although corrosiveness does not have a unit of measure, corrosiveness can be technically measured and descri bed. Procedures that can identify corrosion (or the absence of corrosion) in a Class VI well provide valuable operational information that the Director needs to determine appropriate standards for the t ubing and packer. EPA believes that this subpart accounts for all characteristics of the CO2 that coul d affect the performance of the tubing and packer, including the chemical content, corrosi veness, temperature, and density.

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: EPA Proposal: (viii) Type or grade of cement; and (ix) Quantity, chemical composition, and temperature of the carbon dioxide
stream.

GWPC Recommendations: (viii) Type or grade of cement and additives; and (ix) Quantity, chemical composition, and temperature of the carbon dioxide
stream.

Rationale: Insert "and additives" in (viii)

Response: EPA agrees with the suggestion that §146.86(b)(1 )(viii) be revised to also address cement additives. In the final GS rule, the subparagraph read s as follows: "Type or gr ade of cement and cement additives."

Other EPA Comment Codes and Descriptions: 3822 2.3.1.1 Depth of surface casing (seeking comment) Comment: EPA Proposal: (2) Surface casing must exte nd through the base of the lowermost USDW and be cemented to the surface.

GWPC Recommendations: (2) Surface casing must extend through the base of the lowermost USDW above the injection zone and be cemented to the surface.

Rationale: Insert "above the injection zone " in (2) after "USDW. " In some parts of the US the USDW is very deep and this standard may preclude geologic sequestration in these areas. EPA should consider allowing the Director to exercise discretion to approve alternative means of ach ieving continuous cement around the well in such areas. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24901

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24902Response: EPA disagrees with the suggested edit or that the surface casing requirements in the GS rule
p reclude injection below deep USDWs. The final GS rule at §146.86(b)(2) requires that surface casing extend through the base of the lowermost USDW and be cemented to the surf ace through the use of a single or multiple strings of cas ing and cement. It does not, however, specify how cementing must be accomplished, and gives flexibility to the owner or operator to propose alternate methods- to provide a sufficient amount of cement to meet the standard that USDWs are protected from endangerment. EPA notes that there are many potential ways to meet the requirement, such as the use of staged cementing.

EPA adds that protection of USDW s is the primary missi on and mandate of th e UIC program and the
p urpose of all requirements for injection wells. A ny injection activity must be demonstrated to not endanger USDWs, regardless of their depth, and if such a demonstration cannot be made, then the activity will not be allowed under UIC requirements or the SDWA.

EPA recognizes concerns re garding construction of Class VI well s where the lowermost USDW is very deep. To further address comments on deep inje ction wells, the final GS rule at §146.95 includes requirements for owners or operators that seek a waiv er of the injection depth requirements. Owners or operators of wells operating under in jection depth waivers must comp ly with additional construction requirements to ensure that wells used to inject above or between USDWs are protective. See the discussion of the waiver approach in the preamble to the final GS rule for additional information.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: EPA Proposal: (3) At least one long stri ng casing, using a suffi cient number of centralizers, must extend to the inj ection zone and must be cemented by circulating cement to the surf ace in one or more stages.

GWPC Recommendations: (3) At least one long string casing, using a sufficient number of centralizers, which at a mini mum, would create a cement bond through the confining zone, and which must extend to the injection zone and must be isolated by placing cement and/ or other isolation technol ogies as necessary to
p rovide adequate isolation of the inject ion zone and provide for protection of USDWs.

Rationale: Cementing to surface is not nece ssary to protect USDWS, and may have negative consequences, as follows. Ce ment to surface would eliminate the ability to monitor pressures in this an nulus and would limit flexibility of remedial options. As revised, the propos al would allow for application and development of alternative technologies. See API RP90 for description of riskbased approach for managing situations involving annular casing pressure. Industry experience with CO2 EOR under th e class II program demonstrates the effectiveness of existing cementing procedures.

Response: EPA does not believe that the cementing re quirements at §146.86 would prevent monitoring, operation and remediation of Class VI wells. Cementing of deep wells has been performed successfully in the past by owners or operators of Class I h azardous and Class I municipal waste disposal wells. Some of these wells, which must meet the same cementing and casing requirements as Class VI wells, are up to 12,000 feet deep an d have been successfull y cemented in a manner that maintains inte g rit y and Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24903allows for all required well testin g, operation, and remediation (EPA , 2001). See the discussion of Class VI well construction requirements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guida nce on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa .gov/type/groundwater/uic/wel ls_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: Rule Provision: 146.86(b)

EPA Proposal: (4) Circulat ion of cement may be accomplished by staging. The Director may approve an alternative me thod of cementing in cases where the cement cannot be recirculated to the surf ace, provided the owner or operator can demonstrate by using logs that the cement does not allow fluid movement behind the well bore.

GWPC Recommendations: Delete

Rationale: Same as above

Response: EPA disagrees that the requirement should be deleted. Section 146.86(b)(4) of the final rule allows alternate methods of staging the cement, at the Director's discretion, provided the owner or operator can demonstrate using logs that the cemen t does not allow fluid movement behind the wellbore.

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3864 2.3.3.2 Use of corrosi on-resistant cements (seeking comment) Comment: EPA Proposal: (5) Cement and cement additi ves must be compatible with the carbon dioxide stream and formation fluids and of sufficient quality and quantity to maintain integrity over the design life of the geologic sequestration project. The integrity and location of the cement shall be verified using technology capable of evaluating cement quality radially and identifying the location of channels to ensure that USDWs are not endangered.

GWPC Recommendations: (5) Ce ment and cement additives must be suitable for use with the carbon dioxide stream and formation fluids and of sufficient quality and quantity to maintain integrity ove r the operating life the well. The integrity and location of the cement shal l be verified using technology capable of evaluating cement quality radially and identifying the location of channels to ensure that USDW s are not endangered.

Rationale: Experience with CO2 EOR under the class II pro g ram demonstrates the Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24904

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24905effectiveness of existing cementing materials and procedures. Standard API cements have been used in numerous CO2 EOR operations without adverse consequences. Reference API CO2 EOR report and Carey et al. Bill Carey (SACROC) and Walter Crow (CCP2 - placement and annular gap more important than type).

Once the well is plugged, the plug will is olate the other portions of the well from the injected fluids.

Response: EPA clarifies that the requireme nt at §146.86(b)(5) is that cement and cement additives must be compatible with the CO2 stream and formation fluids and of sufficient quality and quantity to maintain integrity over the design life of the GS proj ect. The rule does not specify materials to be used; rather, it provides owners or operators with the flex ibility to choose, as long as the materials used in Class VI wells are compatible with fluids with which they may come into contact and meet or exceed standards developed for such materials by API or ASTM International, or comparable standards approved by the Director.

EPA recognizes that the oi l and gas industry has decades of experi ence injecting CO2 for the purpose of enhanced recovery, and that this practice has led to the development of many measures that would be appropriate for the design of Class VI wells.

EPA disagrees that the casing, cement or other materials should only be designed for the period of the injection process, rather than the life of the sequestration project. GS projects ar e anticipated to have long life spans in comparison to othe r types of deep inject ion wells. Not only must Class VI wells be able to function safely and properly over the lifespan of the GS project, but th ey must be constructed such that USDWs remain protected after well plugging. The requirement s at §146.86 will ensure that the well can maintain integrity throughout the proposed life span of the pr oject, including after the injection well is plugged and through post-i njection site care peri od and beyond. While the risk profile of a GS site will decrease following cessati on of injection, EPA believes that Cl ass VI wells must be designed to
p rotect USDWs from endangerment for the life of the project. Furthermore, rigorous casing and cementing help ensure that the Class VI well will not serve as a conduit for movement of fluids associated with future injection operations.

Additionally, EPA is developing guida nce on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa .gov/type/groundwater/uic/wel ls_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3826 2.3.1.3 Packer requirements (seeking comment) Comment: Rule Provision: 146.86(c)

EPA Proposal: (c) T ubing and packer.

(1) All owner and operators of Class VI wells must inject fluids through tubing with a packer set at a depth opposite a cemented interval at the location approved by the Director.

(2) In order for the Director to determine and specify requirements for tubing and packer, the owner or operator must submit the following information:

(i) Depth of settin g ; Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24906(ii) Characteristics of the carbon dioxide stream (chemical content, corrosiveness, temperature, and density);

GWPC Recommendations: (c) Tubing and packer.

(1) All owner and operators of Class VI wells must inject fluids through tubing with a packer set at a depth opposite a cemented interval at the location approved by the Director.

(2) In order for the Director to determine and specify requirements for tubing and packer, the owner or operator must submit the following information:

(i) Depth of setting; (ii) Composition of the carbon dioxide stream;

Rationale: What does corrosiveness mean? How is it measured?

Cannot measure the corrosiveness of a carbon dioxide stream.

Composition of the cO2 stream is needed to design a tubing and packer system. The other listed characteristics are not needed.

Response: As written, the text at §146.86(c)(3)(ii) accounts fo r all characteristics of the CO2 that could affect the performance of the tubing and packer , including the chemical content, corrosiveness, temperature, and density. The suggest ed revision to refer to CO2 "composition" would be less precise. EPA clarifies that, although corrosiveness does not have a unit of measure, corrosiveness can be technically measured and described. Procedures that can identify corro sion (or the absence of corrosion) in a Class VI well provide valu able operational information that the Director needs to determine appropriate standards for the tubing and packer.

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3826 2.3.1.3 Packer requirements (seeking comment) Comment: Rule Provision: 146.86(c)(2)

EPA Proposal: (iii) Injection pressure; (iv) Annular pressure; (v) Injection rate (intermi ttent or continuous) and volume of the carbon dioxide stream; (vi) Size of casing; and (vii) Tubing tensile, burst, and collapse strengths.

GWPC Recommendations: (iii) Maximum proposed Injection temperature and pressure; (iv) Maximum proposed Annular pressure; (v) Maximum proposed In j ection rate (intermittent or continuous) and volume of Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24907the carbon dioxide stream;

Rationale: It is more helpful to know the recommended information.

The GWPC also recommends addition of the term "proposed in (iii), (iv) and (v) as this section relates to an applicati on and not to actual established permit conditions

Response: EPA has revised §146.86(c)(3)(iii) and (iv) to reference the maximum proposed injection
p ressure and maximum proposed annular pressure, respectively. EPA has revised §146.86(c)(3)(v) to read "proposed injection rate (intermittent or cont inuous), and volume and/or mass of the carbon dioxide stream." EPA believes that refe rence to the continuous injection rate would be duplicative of the maximum rate. EPA believes that considering the maximum injection and annul ar pressure would be more protective.

Other EPA Comment Codes and Descriptions: 4110 2.4.1.1 Injection pressure limitations Comment: Rule Provision: 146.88

EPA Proposal: 8. Injection we ll operating requirements

(a) Except during stimulation, the owner or operator must ensure that injection
p ressure does not exceed 90 percent of the fracture pressure of the injection zone so as to assure that the inject ion does not initiate new fractures or
p ropagate existing fra ctures in the injection zone. In no case may injection
p ressure initiate fractures in the confining zone(s) or cause the movement of injection or formation fluids that endangers a USDW.

GWPC Recommendations: (a) The owner or operator must comply with a maximum injection pressure limit approved by the Di rector and specified in the permit. In approving a maximum injection pressure li mit, the Director shall consider the results of well tests and, where appropr iate, geomechanical or other studies that assess the risks of tensile failure and shear failure. The Director shall approve limits that, with a reasonable degree of certainty, will avoid initiation or propagation of fractures in the confining zone or cause otherwise non-transmissive faults transecting the confining zone to become transmissive. In no case may injection pressure cause movement of inject ion or formation fluids in a manner prohibi ted by 40 CFR Part 144.12(a).

Rationale: Maintaining the integrity of the confining zone is the critical
p arameter. We believe establishing a maxi mum pressure based on an arbitrary
p ercentage of injection zone fracture pressure does not address the issue of confining zone integrity in an appropriate way.

Response: EPA notes that because determination of the in jection pressure limit is based on the fracture
p ressure of the injection zone, the limit is site-specific and not arbitrary. EPA em phasizes that injection
p ressure limits are important to prot ect against fracturing of the confining zone, and that the requirement at §146.88(a) that the pressure in the injection zone not exceed 90 percent of the fracture pressure
p rovides a mar g in of safet y in the well operation and protects USDWs from endan g erment. If the Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24909Director determines, based on a review of the information collected as pa rt of site characterization, that a lower injection pressure limitation is appropriate, the Di rector has the authority to set a lower limit in the operating permit than the limi t established in the rule.

EPA notes that during the site charac terization process, owners or opera tors must submit data about the geology of the site, as specified at §146.82(a), including data on known or suspected faults and fractures and geomechanical information on frac tures, stress, ductility, rock strength, and in situ fluid pressures within the confining zone. The Director will use these data to determine appropriate limits on injection.

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators in meeting the requirements of §146.82 a nd to assist directors in eval uating permit applications. The guidance will describe recommended approach es for characterizing the regional geology and hydrogeology of a proposed site and performing th e necessary geochemical, geomechanical, and geophysical analyses of the inject ion and confining zone. EPA is al so developing guidance for primacy agencies that will include recommended approaches for evaluating owner or operator-submitted data in setting permit conditions. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 4100 2.4.1 Injection parameters Comment: EPA Proposal: (b) Injection between the outer-most casing protecting USDWs and the well bore is prohibited.

GWPC Recommendations: (b) Injection of the CO2 stream between the outermost casing protecting USDWs and the well bore is prohibited.

Rationale: Routine injection into zones other than the target interval(s) should be prohibited, however, wording of this requirement is not clear as to which interval is being addressed. An absolu te prohibition on injection may also limit diagnostic options that could be useful.

Sometimes inject other things to remediate well.

Response: EPA retains the provision as propos ed, and clarifies that injection between the casing and the well bore is prohibited. This is consistent with requirements for other injection well classes.

Other EPA Comment Codes and Descriptions: 4100 2.4.1 Injection parameters Comment: EPA Proposal: (c) The owner or operator must fill the annulus between the tubing and the long string casing with a non-corr osive fluid approved by the Director. The owner or operator must maintain on th e annulus a pressure that exceeds the operating injection pressure, unless the Director determines that such requirement might harm the integrity of the well.

GWPC Recommendations: (c) The owner or ope rator must fill the annulus between the tubing and the long stri ng casing with a corrosion inhibiting fluid approved by the Director. The owner or operator must maintain a positive pressure on the Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24910

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24911annulus.

Rationale: Agency and Industry experience wi th the Class II UIC program does not support this requirement. The standard proposed by EPA is consistent with neither the risk level related to CO2 nor the specifications needed to monitor the annular space for leakage.

Rule Provision: 146.88(d)

EPA Proposal: (d) Other than during peri ods of well workover (maintenance) approved by the Director in which the se aled tubing-casing annulus is of necessity disassembled for maintenance or corrective pr ocedures, the owner or operator must maintain mechanical integrit y of the injection well at all times.

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA believes that maintaining an annulus pressure that is highe r than the injection pressure, as required at §146.88(c), is appropriate and will ensure that if there are leaks in the tubing, the annulus fluid will move into the tubing, rather than the injectate moving out of the tubing and potentially along the outside of the well. EPA believes this require ment is appropriate for Class VI wells given the
p otential high volumes and supercriti cal nature of the CO2 injectate, potential geomechanical stresses in the wellbore, and the potential for movement of the CO2 in the event of a mechanical integrity loss.

EPA disagrees that maintaining an annulus pressu re higher than the inj ection pressure impacts continuous pressure monitoring for internal MI. The purpose of continuous pressure monitoring (to demonstrate internal MI) is to demonstrate that no pressure changes are occurring, because a drop in
p ressure on the annulus provides an early indication that attention is needed to prevent a loss of MI or unacceptable fluid movement. EPA believes that any change in the pressure on the annulus between tubing and long stem casing, regardless of what the annulus pressure is relative to injection pressure, can indicate a leak.

EPA agrees with the commenter that maintaining mechanical integrity is an essential component of
p rotecting USDWs. The final rule re tains a requirement to maintain mechanical integr ity at §146.88(d).

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: Rule Provision: 146.88

EPA Proposal: (e) The owne r or operator must inst all and use continuous recording devices to monitor: The inje ction pressure; the rate, volume, and temperature of the carbon dioxide str eam; and the pressure on the annulus between the tubing and the long string casing and annulus fluid volume; and must install and use alarms and automatic down-hole shut-off systems, designed to alert the operator and shut-in the well when operating parameters such as annulus pressure, injection rate or other parameters approved by the Director diver g e be y ond permitted ran g es and/or g radients specified in the permit; Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24912GWPC Recommendations: (e) The owner or ope rator must install and use continuous recording devices to monitor: the injection pressure; the rate, volume, and temperature of the carbon di oxide stream. The owner or operator must regularly monitor the pressure on the annulus be tween the tubing and the long string casing. The owner or operator must install, test and use alarms and automatic shut-off systems, designed to alert the operator and shut-in the well when operating parameters such as injection rate, injection pressure, or other
p arameters approved by the Director di verge beyond ranges and/or gradients specified in the permit;

Rationale: Over-pressure protection is be st achieved by ensuring compatibility of the casing/tubing material design st rength with the surface injection (compression) system. Down-hole shut-in devices may be appropriate, however, for site-specific situations of unique pot ential impact (such as offshore or near airports), but they should not be mandated for all injection sites.

Response: EPA acknowledges that proper de sign of the well, including appropriate materials and emplacement of casing and tubing, is essential to proper operation of the well so that USDWs are
p rotected. Such design, however, does not eliminate the possibility of failure, e.g., due to ove r

p ressurization as suggested by the co mmenter. EPA believes that a mu ltiple-barrier approach, which includes appropriate well design as required at §146.86, su itable injection pressure limits as required at §146.88(a), and automatic shut-off systems, as required at §146.88(e), is necessary to ensure protection of USDWs from endangerment from th e risks associated with CO2 GS.

After evaluating the risks and benefits of down- hole shut-off systems a nd considering additional research, EPA will not require auto matic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells in stall automatic surface shut-off devices. The rule affords Director's discretion to mandate automatic down-hole shut-off devices in onshore situations that may warrant their use. Ho wever, the Agency believes that offshore Class VI wells present unique construction and operational conditions, including isolation from shorelines and the need to construct wells through the water column a nd the subsurface, which may delay response time in the event of well difficulties. The rule requires, at §146.88(e)(3), that owners or operators of offshore wells within State territorial wate rs install automatic down-hole shut -off systems. EPA believes that these requirements at §146.88(e) ensure that proper pr ecautions are taken to pr event subsurface fluid movement and ensure protection of USDWs.

While EPA acknowledges that the likelihood of damage to onshore facilities is lower than that for offshore facilities, down-hole shut-off va lves are still commonly used in ons hore facilities such as acid gas injection wells and high pressure, high-temperature wells. While valve failure is a concern, EPA believes that technology has advanced sufficiently to make valve failure a rare occurrence and to appropriately handle such failure if it occurs. For ex ample, wireline retrievable devices can allow repair or replacement of damaged devices wi thout necessitating pulling the tubing.

Other EPA Comment Codes and Descriptions: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment) Comment: Rule Provision: 146.88 Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24913EPA Proposal: (f) If a down-hole automatic shutdown is triggered or a loss of mechanical integrity is discovered, the owner or operator must immediately investigate and identify as expeditiously as possible the cause of the shutoff. If, upon such investigation, the well a ppears to be lacking mechanical integrity, or if monitoring required unde r paragraph (e) of this section otherwise indicates that the well may be lacking mechanical integrity, the owner or operator must:

GWPC Recommendations: (f) If an automatic shutdown is triggered or a loss of mechanical integrity is discovered, the owner or operator must immediately investigate and identify as expeditiously as possible the cause. If, upon such investigation, the well app ears to be lacking mechan ical integrity, or if monitoring required under paragraph (e) of th is section otherwise indicates that the well may be lacking me chanical integrity, the owner or operator must:

Rationale: Eliminates requirement for down-hole shutoff device. Although the use of downhole shutoff valves may be needed in some applications, their required use would be less than ideal for many reasons such as the fact that since they are a downhole installation, inte grity and maintenance of the valves is difficult. Further the installation of surface valves would allow for more control and provide for visual inspecti on. Since the key is to shut down the injection flow if a parameter is exceede d, the use of surface valves would be j ust as effective as downhole valves.

Response: As described above, EPA will not require au tomatic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells install automatic surface shut-off devices. The rule affords Director's discretion to mandate automatic down-hole shut-off devices in onshore situations that may warrant their use. The rule requires, at §146.88(e)(3), that owners or operators of offshore well s within State territorial waters install automatic down-hole shut-off systems. Please see the final rule and preamble fo r additional information on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4000 2.4 Proposed Injection Well Operating Requirements ( 40 CFR 146.88) Comment: Rule Provision: 146.88(f)

EPA Proposal: (1) Immediat ely cease injection; (2) Take all steps reasonably necessary to determine whether there may have been a release of the injected carbon dioxide stream into any unauthorized zone; (3) Notify the Director within 24 hours; (4) Restore and demonstrate mechanical integrity to the satisfaction of the Director prior to resuming injection; and (5) Notify the Director when injection can be expected to resume.

GWPC Recommendations: Support the proposed EPA language for (1), (2), and (5) Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24914(3) Notify the Director within 24 hours of discovery; (4) Restore and demonstrate mechanical integrity to the satisfaction of the director as soon as practicable and prior to resuming injection.

Rationale: Needs to be reasonable and allow for time following discovery.

It was felt that some timeframe for restoration of mechanical integrity should be added to (4)

Response: The final rule text at §146.88(f) now reads, "I f a shutdown (i.e., down-hole or at the surface) is triggered or a loss of mechanical integrity is discovered." Therefore the notice required at §146.88(f) (3) must be provided within 24 hours of an automati c shut-off device being triggered or a loss of mechanical integrity being discovered. EPA believes this provision is necessary to ensure timely response to potential USDW endangerment.

Other EPA Comment Codes and Descriptions: 4500 2.5 Proposed Mechanical Integrity Testing (MIT) Requirements (40 CFR 146.89) Comment: Rule Provision: 146.89

EPA Proposal: 9. Mechanical integrity

(a) A Class VI well has mechanical integrity if:

(1) There is no significant leak in the casing, tubing or packer; and (2) There is no significant fluid movement into a USDW through channels adjacent to the injection well bore.

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment and the final rule retains the text at 146.89(a) as proposed. For additional information, please see the discu ssion of MITs in the final rule preamble.

Other EPA Comment Codes and Descriptions: 4520 2.5.1 Continuous internal mechanical integrity monitoring (seeking comment); 4720 2.7.2 Oper ational recordkeeping and reporting Comment: EPA Proposal: (b) To evaluate the absenc e of significant leaks under paragraph (a)(1) of this section, owne rs or operators must, following an initial annulus
p ressure test, continuously monitor inject ion pressure, rate, injected volumes, and pressure on the annulus between tubing and long stem casing and annulus fluid volume as specified in § 146.88(e);

GWPC Recommendations: (b) To evaluate the absence of significant leaks under
p aragraph (a)(1) of this sect ion, owners or operators must, following an initial annulus pressure test, continuousl y monitor and record at least dail y in j ection Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24915

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24916p ressure, rate, injected volumes, and pressure on the annulus between tubing and long stem casing and annulus flui d volume as specified in §146.88 (e);

Rationale: We believe that injection para meters must not only be monitored but should be recorded at least daily. We furt her believe the use of monitoring with digital equipment which records readings on an appropriate frequency should be considered continuous for purposes of this section.

Response: EPA believes that continuous pressure monitoring to demonstrate internal mechanical integrity of Class VI we lls required at §146.89(b) is important, give n the potential corrosive impact of CO2 and impurities on well ma terials, the potential geomechanical im pacts to well integrity due to CO2
p hase changes, and the temperature and pressure ef fects associated with injecting supercritical CO2. EPA also believes that the technology for continuous monitoring is practicable, available, and is currently in fairly wide use. Class VI injection we lls will be equipped with dedicated computer-based continuous pressure monitoring devices (in concert with the shut-off systems required for GS wells), which typically take readings several times per second (i.e., more frequently than daily) and record them electronically in a computer system. 40 CFR §146.91(a)(2) requires that monthly averages of the continuous annulus monitoring be reported on a semia nnual basis. For additional information, please see the discussion of MITs in the final rule preamble.

Other EPA Comment Codes and Descriptions: 4540 2.5.2 Proposed external MIT requirements; 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: Rule Provision: 146.89(c)

EPA Proposal: (c) At least once per year, the owner or operator must use one of the following methods to determine the ab sence of significant fluid movement under paragraph (a)(2) of this section:

(1) A tracer survey such as oxygen-activation logging; (2) A temperature or noise log; or (3) A casing inspection log, if required by the Director.

GWPC Recommendations: (c) At least once per year, the owner or operator must confirm the absence of significant fluid m ovement under paragraph (a)(2) of this section using a method acceptable to the Director (e.g. including diagnostic surveys such as oxygen-activation logging or temperature or noise logs).

Delete (1) Delete (2) Delete (3)

Rationale: Revised text supports a perfor mance-based approach and allows the development and use of new technologies as they become available.

Response: EPA believes that the MITs described in §146.89( c) of the rule (e.g., an approved tracer log or temperature or noise logs) are effective methods to demonstrate external MI, provide an important early warning of potential problems in the injection well system, and represent standard techniques that have been used successfull y b y the drillin g industr y and for the UIC Pro g ram for decades. The A g enc y Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24917notes that the regulations do pr ovide the Director flexibility at §146.89(e) to approve the use of alternative MIT methods.

EPA agrees that the casing inspection log is not an appropriate test to detect fluid movement behind the casing, but clarifies that it is appropr iate to be used to determine the presence or absence of corrosion of the long-string casing, and is required if the Director determines that it is necessary based on sitespecific information. EPA has revised the final GS rule to require that the frequency of the casing inspection log must be specified in the appr oved testing and monitoring plan. See §146.89(d).

Other EPA Comment Codes and Descriptions: 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: EPA Proposal: (d) The Director may require a ny other test to evaluate mechanical integrity under paragra ph (a)(1) or (a)(2) of this s ection. Also, the Director may allow the use of a test to demonstrat e mechanical integrity other than those listed above with the written approva l of the Administrator. To obtain approval, the Director must submit a writ ten request to the Administrator, which must set forth the proposed test and all technical data supporting its use. The Administrator must approve the request if it will reliably demonstrate the mechanical integrity of wells for whic h its use is proposed. Any alternate method approved by the Administrator will be published in the Federal Register and may be used in all States in accord ance with applicable State law unless its use is restricted at the time of approval by the Administrator.

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment and the final rule retains the text as proposed.

Other EPA Comment Codes and Descriptions: 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: Rule Provision: 146.89(e)

EPA Proposal: (e) In conduc ting and evaluating the tests enumerated in this section or others to be allowed by the Director, the owner or operator and the Director must apply methods and standards generally accepted in the industry. When the owner or operator reports the resu lts of mechanical integrity tests to the Director, he/she shall include a description of the test(s) and the method(s) used. In making his/her evaluation, the Director must review monitoring and other test data submitted since the previous evaluation.

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24918

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24919Response: EPA acknowledges the comment and the fina l rule retains the text as proposed.

Other EPA Comment Codes and Descriptions: 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) Comment: EPA Proposal: (f) The Director may require additional or alternative tests if the results presented by the owner or operator under paragraph (d) of this section are not satisfactory to the Dire ctor to demonstrate that there is no significant leak in the casing, tubing or packer or signifi cant movement of fluid into or between USDWs resulting from the injection activity as stated in
p aragraphs (a)(1) and (2) of this section.

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment and the final rule retains the text as proposed.

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Rule Provision: 146.90

EPA Proposal: 10. Testing a nd monitoring requirements

The owner or operator of a Class VI well must prepare, maintain, and comply with a testing and monitoring plan to verify that the geologic sequestration project is operating as permitted and is not endangering USDWs. The testing and monitoring plan must be submitted with the permit applicat ion, for Director approval, and must include a description of how the owner or operator will meet the requirements of this section. Testing and monito ring associated with geologic sequestration projects mu st, at a minimum, include:

GWPC Recommendations: Support the proposed EPA language.

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has ma de many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

EPA agrees with commenters that developing a nd following testing and monitoring plans is an important part of assuring that a GS project is opera ting properly and is crucial for the early detection of
p otential endangerment to USDWs. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24920

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24922

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24923Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: Rule Provision: 146.90

EPA Proposal: (a) Analysis of the car bon dioxide stream with sufficient frequency to yield data representati ve of its chemical and physical characteristics;

(b) Installation and use, except during well workovers as defined in § 146.86(d), of continuous recording devices to monitor injection pressure, rate and volume; the pressure on the annulus between the tubing and the long string casing; and the annulus fluid volume;

GWPC Recommendations: Support the proposed EPA language in (a)

(b) Installation and use, except during well workovers as defined in §146.88(d), of continuous monitoring de vices (including digital de vices capturing periodic data) to monitor injection pressure, rate and volume; and record at least daily the pressure on the annu lus between the tubing and the long string casing;

Rationale: 146.86(d) does not exist; perhap s 146.88(d) is what was apparently intended.

Response: EPA acknowledges the comment; the final rule retains the language in §146.90(a) as
p roposed. EPA adds that the fina l GS rule references §146.88(e), as the commenter suggests.

Regarding §146.90(b), based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EP A has made many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: Rule Provision: 146.90

EPA Proposal: (c) Corrosion monitoring of th e well materials for loss of mass, thickness, cracking, pitting a nd other signs of corrosion must be performed on a quarterly basis to ensure that the well components meet the minimum standards for material strength and performance set forth in § 146.86(b) by:

GWPC Recommendations: c) Corrosion monitoring of the well materials for loss of mass, thickness, cracking, pitting and other signs of corrosion must be
p erformed and recorded at least quarter ly and may be modified to be less frequent as approved by the Director ba sed on construction materials, operating conditions, and monitoring history to ensure that the well components meet the minimum standards for material strengt h and performance set forth in §146.86(b) by:

Rationale: Allows application of performance based approach. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24924Rationale: Allows less frequent moni toring, for example, where corrosion resistant materials are used.

Response: EPA believes that quarterly corrosion monitoring is appropr iate given the potentially corrosive nature of the CO2 str eam. CO2 in the presence of wa ter becomes acidic, potentially accelerating corrosion of well materials. The CO2 stream for a GS project may also contain small volumes of impurities that could contribute to corrosion. For these reasons, the final rule requires quarterly corrosion monitoring, at §146.90(c).

Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4630 2.6.3 Corrosion monitoring Comment: Rule Provision: 146.90(c)

EPA Proposal: (1) Placing coupons of the we ll construction materials in contact with the carbon dioxide stream; or (2) Routing the carbon dioxi de stream through a loop constructed with the material used in the well; or (3) Using an alternative method approved by the Director;

GWPC Recommendations: (1) Analyzing coupons of the well construction materials
p laced in contact with the carbon dioxide stream; or (2) Routing the carbon dioxi de stream through a loop constructed with the material used in the well and inspec ting the materials in the loop; or (3) Using an alternative method, materi als, or time period approved by the Director;

Rationale: Clarification edits

Response: As described above, EPA believes that quarter ly corrosion monitoring is appropriate given the potentially corrosive nature of the CO2 stream . Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has made many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 4660 2.6.6 Geochemical monitoring Comment: Rule Provision: 146.90(d)

EPA Proposal: (d) Periodic monitoring of the ground water quality and geochemical changes above the confining z one(s) that may be a result of carbon dioxide movement through the confining z one or additional identified zones:

(1) The location and number of monitoring wells must be based on specific information about the g eolo g ic sequestration pro j ect, includin g in j ection rate Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24925

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24926and volume, geology, the presence of artifi cial penetrations and other factors;

(2) The monitoring frequency and spatial distribution of monitoring wells must be based on baseline geochemical data that has been collected under § 146.82(a) (6) and any modeling results in the ar ea of review evaluation required by § 146.84(b);

GWPC Recommendations: (d) Periodic moni toring of reservoir formation fluid quality in a permeable and porous formation as near as practicable to the confining zone(s) for geochemical changes th at may be a result of carbon dioxide or displaced formation fluid movement:

(1) The location and number of monitoring wells must be based on specific information about the geol ogic sequestration project, including injection rate and volume, geology, the presence of artifi cial penetrations and other relevant factors as warranted by a risk-assessment;

(2) The monitoring frequency and spatial distribution of monitoring wells must be based on geological, geochemical and ge ophysical data that has been collected under §146.82(d) and any modeling results in the area of revi ew evaluation required by §146.84(b);

Rationale: Drilling monitoring wells should be carefully considered since each well introduces a potential pathway for movement.

[Geochemical data do not have a high degr ee of relevance in selecting monitoring well sites.]

Response: EPA believes that monitoring us ing wells in the injection zone, e.g., for pressure monitoring as required at §146.90(g)(1), can be safely performe d if the wells are constructed to prevent flow between the injection zone and US DWs or other layers above the c onfining zone. Such construction technologies exist and have been used in the oil a nd gas industry for years. EPA believes that properly constructed monitoring wells will be a safe way to obtain the data that is essential to ensure that the injected CO2 remains confined in the injection zone and that pressure changes are not causing movement of formation or other fl uids. To mitigate the risk of fl uid movement, EPA requires owners and operators to submit a testing and monitoring plan that describes how the owner or operator plans to site and construct monitoring wells. EPA has deve loped a brief technical paper on construction of monitoring wells that perforate the confining zone; this paper can be found in the rulemaking docket. EPA is also developing guidance on well construction that will include recommendations for monitoring well construction. The guidance will be available on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm. Baseline characterization of the si te, including the geochemical data a nd initial modeling, will be highly valuable in selection of monitoring well locations and in refining plans for monitoring frequency. The GS rule stipulates that the moni toring frequency and spatial distribut ion of monitoring wells must be based on baseline geochemical data that were collected during the init ial site characterization and the area of review evaluation (§146.90(d)(2 )). The details of the geochemi cal monitoring must be based on site-specific information and de scribed in the Director-approved testing and monitoring plan.

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24927Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: Rule Provision: 146.90

EPA Proposal: (e) A demonstrat ion of external mechanical integrity pursuant to § 146.89(c) at least once per year throughout the durat ion of the geologic sequestration project;

(f) A pressure fall-off test at least once every five years unless more frequent testing is required by the Director ba sed on site specific information;

GWPC Recommendations: (e) A demonstration of external mech anical integrity
p ursuant to §146.89(c) at least once per year until the well is plugged;

(f) A pressure fall-off test or other equivalent test th at identifies reservoir conditions with respect to flow dynamics at least once every five years unless more frequent testing is required by th e Director based on site specific information;

Rationale: Redundant to section 146.89

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has ma de many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

EPA believes that pressure fall-off testing is necessa ry for GS wells. Pressure fall-off tests are designed to verify that modeled projections of reservoir pressure decline agree with measured pressure decline
p rofiles. These tests can be useful in AoR calc ulations and reevaluations and may also indicate mischaracterization of site geology and the presence of leakage pathways. EPA therefore believes that
p ressure fall-off testing is necessary every five years at a minimum, and the final GS regulation includes this requirement at §146.90(f). Pressure fall-off tests may be conducte d in conjunction with other well
p erformance tests (i.e., mechanical integrity test ing) to ensure safe a nd effective operations.

Other EPA Comment Codes and Descriptions: 4650 2.6.5 CO2 plume and pressure front tracking (seeking comment) Comment: EPA Proposal: (g) Testing and monitoring to track the extent of the carbon dioxide plume and the position of the pre ssure front by either monitoring for
p ressure changes in the first formation overlying the confining zone or using indirect, geophysical tec hniques (e.g., seismic, electrical, gravity, or electromagnetic surveys and/or down-hol e carbon dioxide detection tools);

GWPC Recommendations: (g) Testing and m onitoring to track the extent of the carbon dioxide plume and the position of the pressure front.

Rationale: Monitoring outside of the inje ction zone provides little information of value for tracking and monitoring the injected plume. Exam ples of how to test and monitor could be included in th e Preamble but need not be included in the rule itself. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24928Response: EPA has revised this requirement in the fina l rule. The final GS regulation, at §146.90(g)(1), requires all GS project owners or operators to moni tor for pressure changes in the injection zone. EPA believes that pressure monitoring in the injecti on zone is necessary to track the development and movement of the pressure front and CO2 plume.

Pressure monitoring within the injection zone is necessary because any such monitoring above the confining zone would not detect movement of the pr essure front unless a breach of the confining zone occurs. EPA believes that monitoring using wells in th e injection zone (i.e., that penetrate the confining zone) can be safely performed if the wells are constructed to prevent flow between the injection zone and USDWs or other layers above the confining z one. Such construction technologies exist and have been used in the oil and gas indus try for years. EPA believes that the benefits of monitoring in the injection formation outweigh the mana geable risk of those monitoring we lls serving as conduits for fluid movement. EPA adds that owners or operators may consider perfor ming additional pressure monitoring in wells that are above th e confining zone (e.g., in the same well s used to perform ground water quality monitoring required at §146.90(d)) to provide additi onal verification that no pressure changes are occurring above the confining zone due to CO2 leakage. Monitoring al so identifies needed remedial actions, provides inputs for AoR r eevaluation modeling, and targets a dditional geochemical and surface monitoring needs. Knowledge of the location of the CO2 plume and the associated pressure front will assure the public that GS projects are proceeding accord ing to plan, provide sufficient information to the owner or operator and Director, or allow for appropriate actions to address any indication that USDWs may be endangered.

EPA acknowledges that, at ce rtain sites, there may be a need for more or different monitoring schemes (which may include monitoring in the confining zone), and adds that it is important to balance the need for adequate monitoring that ensures USDW protec tion from endangerment agai nst too many artificial
p enetrations which could serve as conduits for fluid migration. Site-specific te sting and monitoring plans should describe the proposed monitoring regime, which must be approved by the Director. Flexibility is also provided regarding how to monito r for the specific data required by the final rule. The testing and monitoring plan is developed by the owner or operator in consultati on with the Director and is designed to ensure that a detailed, Director -approved document describing how monitoring will be conducted during the lifetime of the project exists. EPA is de veloping guidance on testing and monitoring to assist owners or operators and Directors in evaluating requirements under §146.90, including proposed monitoring plans. The guidance describes availabl e technologies and recommended approaches for implementing a testing and monitoring plan, in cluding pre-operational geophysical logging and testing of injection we lls, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm.

Other EPA Comment Codes and Descriptions: 4670 2.6.7 Surface air monitoring and/or soil gas monitoring (seeking comment) Comment: Rule Provision: 146.90

EPA Proposal: (h) At the Director’s di scretion, surface air monitoring and/or soil gas monitoring to detect movement of carbon dioxide that could endanger a USDW. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24929GWPC Recommendations: (h) At the Directo r ’s discretion based on site-specific conditions and risk-based factors, su rface air monitoring and/or soil gas monitoring to detect movement of carbon dioxide that could endanger a USDW.

Rationale: In most situations soil a nd air monitoring does not provide an effective method of protecting USDWs.

Response: As described above, EPA acknowledges that air a nd soil gas monitoring are subject to sitespecific limitations and may not be suitable in all settings as a method to ensure USDW protection. However, EPA does not believe that this should entirely preclude their use. The final rule at §146.90(h) retains the allowance for surface air and soil gas moni toring at the discretion of the Director as a means of identifying leaks that may pose a risk to USDWs and informing emergency not ification of a Class VI owner or operator and UIC Director in the event of a USDW endangerment, pur suant to requirements at §146.91(c).

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Rule Provision: 146.90(h)

EPA Proposal: (1) The testi ng and monitoring plan must be based on potential vulnerabilities within the area of review;

(2) The monitoring frequency and spatial distribution of surface air monitoring and/or soil gas monitoring must reflect baseline data and the monitoring plan must include how the proposed monitoring will yield useful information on the area of review delineation and/or compliance with standards under 40 CFR 144.12;

GWPC Recommendations: (1) The testing and monitoring plan must be based on sitespecific geologic factors, modeling, and risk-assessment within the area of review;

(2) Agree with EPA language

Rationale: The GWPC feels that the term "potential vulnerabilities" is too nebulous. We suggest replacing this term with the term "site-specific geologic factors, modeling, and risk-assessment."

Response: Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Comment EPA has ma de many revisions to the GS rule. See the final rule and preamble for further discussion on EPA's final approach.

EPA anticipates that the testing and monitoring pl an will address site-sp ecific geologic factors, modeling, and risk-assessment. EPA is developing guidance on how best to develop the various required
p roject plans, including the testing and monitoring plan. The guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24930

Commenter Name: Michel Paque Letter ID: 0259Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Rule Provision: 146.90(i)

EPA Proposal: (i) Any a dditional monitoring, as required by the Director, necessary to support, upgrade, and improve computational modeling of the area of review evaluation required under § 146.84(b) and to determine compliance with standards under 40 CFR 144.12; and

(j) A quality assurance and surveillance plan for all testing and monitoring requirements.

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. The final rule retains thes e provisions as proposed.

Other EPA Comment Codes and Descriptions: 4760 2.7.6 Proposed reporting frequency (seeking comment) Comment: Rule Provision: 146.91

11. Reporting requirements.

The owner or operator must, at a minimum, provide the following reports to the Director, for each permitt ed Class VI well:

(a) Semi-annual reports containing:

(1) Any changes to the physical, chemical and other relevant ch aracteristics of the carbon dioxide stream from the proposed operating data; (2) Monthly average, maximum and minimum values for injection pressure, flow rate and volume, and annular pressure;

GWPC Recommendations: (a) Semi-annual or at a frequency determined by the Director reports containing:

(1) Any significant changes to the physic al, chemical and other relevant characteristics of the carbon dioxide stream from the proposed operating data;

Rationale: Should be semi-annual unless otherwise determined

Response: EPA is retaining the semi-annual reporting requirements as proposed at §146.91(a). These requirements ensure the Director has the informati on needed to take preventive action in a timely manner to protect USDWs from endangerment. For addi tional information, please see the final rule and the preamble for a discussion of EPA's fina l approach to recordkeeping and reporting. Commenter Or g anization: Ground Water Protection Council Comment ID: 24931

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24932Other EPA Comment Codes and Descriptions: 4720 2.7.2 Operational recor dkeeping and reporting Comment: Rule Provision: 146.91(a)

EPA Proposal: (3) A descript ion of any event that exceeds operating parameters for annulus pressure or injection pres sure as specified in the permit; (4) A description of any event which triggers a shutdown device required
p ursuant to § 146.88(e) and the response taken; (5) The monthly volume of the carbon dioxi de stream injected over the reporting
p eriod and project cumulatively; (6) Monthly annulus fluid volume added; and (7) The results of monitoring prescribed under § 146.90.

GWPC Recommendations: (3) A description of any event that significantly exceeds operating parameters for annulus pressure or injection pressure as specified in the permit; (4) A description of any event which triggers a shutdown device required
p ursuant to §146.88(e) and the response taken;

Rationale: EPA should consider some significance threshold on reporting these events, to avoid reporting events would be of limited interest or consequence.

Response: EPA retained this provision as proposed. The final rule at §146.91(a)(3) requires reporting of all exceedances of operating parameters. EPA disagr ees with the suggestion to report only "significant" exceedances. Making a determination as to whether an exceedance is "significant" is not the purpose of the requirement. EPA believes that the ability of an operator to consistently meet operating requirements and avoid exceedances provides evidence of a well-man aged GS project that is in compliance with the Class VI permit. If multiple exceedances occur, the Director should be aware of such occurrences, and that information will aid in his/ her determination of whether these indicate problems at the site, and what is the appropriate course of action (e.g., a well workover, modification of operating parameters, or imposition of a penalty) to remediate such problem(s).

Other EPA Comment Codes and Descriptions: 4720 2.7.2 Operational recor dkeeping and reporting; 4740 2.7.4 Electronic reporti ng (seeking comment) Comment: EPA Proposal: (b) Report, within 30 days the results of:

(1) Periodic tests of mechanical integrity; (2) Any other test of the injection well conducted by the permittee if required by the Director; and (3) Any well workover.

(c) Owners or operators must submit repor ts in an electronic format acceptable to the Director. At the discretion of the Director , other formats may be accepted.

GWPC Recommendations: Support the proposed EPA language. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24933

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24934Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. Please see the final rule and the discussion of reporting
p reamble for additional information on EPA's final rulemaking approach.

EPA believes that electronic formatting is the most appropriate format for su bmitting Class VI project information to the Director, and that many GS well owners or operators will have the capability to report electronically.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92

EPA Proposal: 12. Injection well plugging.

(a) Prior to the well plugging, the owner or operator must flush each Class VI injection well with a buffer fluid, determine bottomhole reservoir pressure, and
p erform a final mechani cal integrity test.

GWPC Recommendations: (a) Prior to the we ll plugging, the owner or operator must flush each Class VI inject ion well with a buffer fluid, determine bottomhole reservoir pressure, and perf orm a final external mech anical integrity test.

Rationale: Many of the components that woul d be tested by an internal MIT are removed or tested during the plugging pro cess. Consequently, the GWPC suggests including the term internal to the language for clarification.

Response: EPA agrees that only an external MIT is re quired, and has modified the GS rule at §146.92 (a) to require owners or operators to perform a final external mechanical integrity test prior to the well
p lugging.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(b)

EPA Proposal: (b) Well Plugging Plan. The ow ner or operator of a Class VI well must prepare, maintain, and comply with a plan that is acceptable to the Director. The requirement to maintain and implement an approved plan is directly enforceable regardless of whethe r the requirement is a condition of the
p ermit. The well plugging plan must be submitted as part of the permit application and must include the following information:

GWPC Recommendations: Support the proposed EPA language.

Rationale: A g ree with EPA’s rationale. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24935

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24936Response: EPA acknowledges the commente r’s support; the final rule retains this provision.

Other EPA Comment Codes and Descriptions: 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: EPA Proposal: (1) Appropriate test or measure to determ ine bottomhole reservoir
p ressure; (2) Appropriate testing methods to ensure mechanical integrity as specified in § 146.89; (3) The type and number of plugs to be used; (4) The placement of each plug including th e elevation of the top and bottom of each plug; (5) The type and grade and quantity of ma terial to be used in plugging. The material must be compatible with the carbon dioxide stream; and (6) The method of placement of the plugs.

GWPC Recommendations: Support the proposed EPA language for (1), (3), (4) and (6)

(2) Appropriate testing methods to ensure final external mechanical integrity as specified in §146.89(c);

(5) The type and grade and quantity of ma terial to be used in plugging. The material must be suitable for use with the carbon dioxide stream; and

Rationale: Many of the components that woul d be tested by an internal MIT are removed or tested during the plugging pro cess. Consequently, the GWPC suggests adding the term external to th e language for clarification.

Response: Regarding the suggested edit at 146.92(b)(2), EPA agrees that only an external MIT is required, and has modified the GS rule at §146.92(a) to require owners or opera tors to perform a final external mechanical integrity test prior to the well plugging.

Regarding the edit at 146.92(b)(5), EPA believes, cons idering the potentially corrosive nature of CO2 when it is in contact with water, that the requirement that the material must be compatible with the CO2 stream is appropriate. The final rule retains this requirement.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: EPA Proposal: (c) Notice of intent to pl ug. The owner or operator must notify the Director at least 60 da ys before plugging of a well. At this time, if any changes have been made to the original well plugging plan, th e owner or operator must also provide the revised well pl ugging plan. At the discretion of the Director, a shorter notice period ma y be allowed. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24937

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24938GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the commente r’s support; the final rule retains this provision.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5100 2.8.1 Injection well plugging activities (seeking comment) (40 CFR 146.92) Comment: Rule Provision: 146.92(d)

EPA Proposal: (d) Plugging report. Within 60 days after plugging or at the time of the next semi-annual report (whichever occurs earlier) the owner or operator must submit a plugging report to the Direct or. If the semi-annual report is due less than 15 days after completion of plugging, then the report must be submitted within 60 days after pluggi ng. The report must be certified as accurate by the owner or op erator and by the person who performed the plugging operation (if other than the owner or operator.)

GWPC Recommendations: (d) Plugging report. Within 60 days after plugging the owner or operator must submit a pluggi ng report to the Director. The report must be certified as accurate by the ow ner or operator and by the person who
p erformed the plugging operation (if other than the owner or operator.)

Rationale: Simplification

Response: EPA has revised the text at §146.92(d) to reduce c onfusion. The final rule text reads, "Within 60 days after plugging the owner or operator must submit a pluggi ng report to the Director."

Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities Comment: Rule Provision: 146.93

EPA Proposal: 13. Post-injection site care and site closure

(a) The owner or operator of a Class VI well must prepare, maintain, and comply with a plan for post-injection site ca re and site closure that meets the requirements of paragraph (a )(2) of this section and is acceptable to the Director.

(1) The owner or operator must submit the post-injection site care and site closure plan as a part of the permit appl ication to be approved by the Director.

GWPC Recommendations: Support the proposed EPA language Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24939

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24940Rationale: Agree with EPA’s rationale

Response: EPA acknowledges the commente r’s support; the final rule retains this provision.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: EPA Proposal: (2) The post-injection site care and site closure plan must include the following information:

(i) The pressure differentia l between pre-injection and predicted post-injection
p ressures in the injection zone; (ii) The predicted position of the carbon dioxide plume and asso ciated pressure front at site closure as demonstrated in the area of review evaluation required under § 146.84(b);

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the commente r’s support; the final rule retains this provision.

Other EPA Comment Codes and Descriptions: 5220 2.8.2.1 Post-injection monitoring activities Comment: Rule Provision: 146.93(a)(2)

(iii) A description of post-injection monitoring location, methods, and proposed frequency; and (iv) A proposed schedule for submitting post-injection site care monitoring results to the Director.

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the commente r’s support; the final rule retains this provision.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: EPA Proposal: (3) Upon cessation of injecti on, owners or operators of Class VI wells must either submit an amended post- injection site care and site closure
p lan or demonstrate to the Director through monitoring data and modeling results that no amendment to the plan is needed. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24941

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24942

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24943GWPC Recommendations: Suppor t the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the commente r’s support; the final rule retains this provision.

Other EPA Comment Codes and Descriptions: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) Comment: EPA Proposal: (4) The owner or operator may modify and resubmit the postinjection site care and site closure plan for the Director’s approval within 30 days of such change.

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the commente r’s support; the final rule retains this provision.

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment); 5280 2.8.2.4 USDW non-enda ngerment demonstrations Comment: Rule Provision: 146.93(b)

EPA Proposal: (b) The owner or operator shall monitor the site following the cessation of injection to show the pos ition of the carbon dioxide plume and
p ressure front and demonstrate that USDWs are not being endangered.

(1) The owner or operator shall continue to conduct monitoring as specified in the Director-approved post-injection site care and site closure plan for at least 50 years following the cessation of injection. At the Director’s discretion, the monitoring will continue until th e geologic sequestration
p roject no longer poses an endangerment to USDWs.

GWPC Recommendations: (b) The owner or ope rator shall monitor the site following the cessation of injection.

(1) The owner or operator shall continue to conduct monitoring as specified in the Director-approved post-injection site care and site closure plan until closure is authorized pursuant to 146.93(b)(3).

Rationale: Eliminate the 50 year requirement.

There is no justification for extending co mpleted projects for the presumptive 50 years, and it will be difficult to accept much shorter demonstration periods with the 50 year presumption in the regul ations. Default 50-year period defeats incentives for best site id entification and best MMV Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24944

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24945N eed for site-specific considerations and use of data

N eed achievable and definable standard

Response: EPA agrees that there will be circumstances wh ere it can be demonstrated in less than 50 years that the plume and pressure front no longer pose a risk of endangermen t to USDWs. For this reason, the final GS regulation incl udes a provision that the Director may, at his or her discretion, shorten the post-injection site care timeframe if the owner or operator can demonstrate that the GS
p roject does not pose an endangerment to USDWs, as specified in §146.93(b)(2). Such a demonstration will be site-specific, and based on pressure monitoring and USDW impa cts. Alternatively, the final rule at §146.93(c), also allows the Director to approve an alternative post-injection si te care timeframe where an owner or operator can demonstrate during the permit ting process that an altern ative post-injection site care timeframe, other than the 50 year default, is appropriate and ensures non-endangerment of USDWs. The demonstration must be based on site-specific information, including the results of site-specific computational modeling; the predicted timeframe fo r pressure decline; the predicted rate of carbon dioxide plume migration; site-specifi c chemical processes that will resu lt in carbon dioxide trapping; the
p redicted rate of carbon dioxide tra pping; characterization of the confining zone(s); laboratory analyses or studies to verify the information on trapping; th e presence of potential conduits for fluid movement and the quality of abandoned well plugs within the Ao R; the distance between th e injection zone and the USDWs above and/or below the injection zone; and any additional site-specifi c factors determined by the Director. The demonstr ation must meet the criteria at §146.93(c)(2) for ensuring the quality and accuracy of the data and models on which the demonstration is based. This demonstration would be submitted as part of the permit application, per §146.82(a)(18), in additi on to the PISC and site closure
p lan required at §146.82(a)(17).

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe for
p ost-injection site care will be necessary in all buta limited number of cases. This default 50 year postinjection site care timeframe repres ents a reasonable and protective m onitoring period based on a review of research studies, industry repor ts, and existing envir onmental programs, and evaluation of public
comments.

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mon itoring and USDW impacts.

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment); 5260 2.8.2.3 Adjusting the post-injection timeframe (seeking comment) Comment: Rule Provision: 146.93(b)

EPA Proposal: (2) If the owner or operato r can demonstrate to the satisfaction of the Director before 50 years, based on monitoring and other site-specific data, that the geologic sequestration proj ect no longer poses an endangerment to USDWs, the Director ma y approve an amendment to the post-in j ection site care and Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24946site closure plan to reduce the frequenc y of monitoring or may authorize site closure before the end of the 50-year period.

GWPC Recommendations: (2) The owner or operator can request and demonstrate to the satisfaction of the Director that th e post-injection site care and site closure plan should be revised to reduce the frequency of monitoring.

Rationale: See above regarding elimination of 50-year presumptive time period.

Response: As described above, EPA disagrees that a post-in jection site care timeframe of 50 years is excessive for most Class VI wells. However, EPA agre es that there will be circumstances where it can be demonstrated in less than 50 years that the plume and pressure front no longer pose a risk of endangerment to USDWs. For this reason, the GS rule offers owners or operators flexibility regarding the duration of the PISC timeframe by: (1) allowing th e Director discretion to shorten or lengthen the PISC timeframe during the post-inj ection period based on site-specific data, pursuant to requirements at §146.93(b); or (2) affording the Direct or discretion to allow a Class VI well owner or operator to demonstrate, during the permitting pr ocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangermen t of USDWs pursuant to requirements at §146.93(c).

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mon itoring and USDW impacts.

Other EPA Comment Codes and Descriptions: 5280 2.8.2.4 USDW non-endangerment demonstrations Comment: EPA Proposal: (3) Prior to authorization fo r site closure, the owner or operator must submit to the Director a demonstrat ion, based on monitoring and other sitespecific data, that the carbon dioxide plum e and pressure front have stabilized and that no additional monitoring is needed to assure that the geologic sequestration project does not pose an endangerment to USDWs.

GWPC Recommendations: (3) Prior to authori zation for site closure, the owner or operator must demonstrate to the Dir ector, based on monitoring, other sitespecific data, and modeling that is reasona bly consistent with site performance, that no additional monitoring is needed to assure that the geologic sequestration project does not and is not expected to pose an endangerment to USDWs. The Director shall approve closure if the owner or operator demonstrates, based on the current understanding of the site, including monitoring data and/or modeling, all of the following: (i) the estimated magnitude and extent of the
p roject footprint (CO2 plume and the ar ea of elevated pressure) ; (ii) the estimated location of the detectable CO2 plume; (iii) that there is no significant leakage of either CO2 or displaced formation fluids that is endangering USDWs; (iv) that the injected or displaced fluids are not expected to mi g rate in the future in a manner that encounters a potential leaka g e pathwa y Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24947into a USDW; (v) that the injection wells at the site completed into or through the injection zone or c onfining zone are plugged a nd abandoned in accordance with these requirements; and (vi) any re maining project monito ring wells at the site are being managed by a person and in a manner acceptable to the Director.

Rationale: The GWPC revised this secti on to establish the performance based criteria for selecting the monitoring period.

Response: EPA disagrees that the rule should specify the criteria for setting th e monitoring timeframe. Instead, EPA believes that such de terminations are site-specific and should be described in a project specific post-injection site care and site closure plan. EPA also be lieves that periodic reviews and updates, where necessary, to the plan are important to ensuring that the site continues to be managed effectively and to determine wh ether shortening the monitori ng timeframe is appropriate.

As described above, EPA agrees that there will be circumstances where it can be demonstrated in less than 50 years that the plume and pressure front no longer pose a risk of endangerment to USDWs. For this reason, the GS rule offers owners or operators flexibilit y regarding the duration of the PISC timeframe by: (1) allowing the Direct or discretion to shorten or lengt hen the PISC timeframe during the
p ost-injection period based on site-specific data, pursuant to requi rements at §146.93(b); or (2) affording the Director discretion to allow a Class VI well ow ner or operator to demonstr ate, during the permitting
p rocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts.

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment); 5260 2.8.2.3 Adjusting the post-injection timeframe (seeking comment) Comment: EPA Proposal: (4) If such a demonstration cannot be made (i.e., if the carbon dioxide plume and pressure front have not stabilized) after the 50-year period, the owner or operator must submit to th e Director a plan to continue postinjection site care.

GWPC Recommendations: Delete

Rationale: No longer necessary if 50 year time period is removed.

Response: As described above, EPA believes that, to en sure USDW protection from endangerment, a default timeframe for post-injection si te care is necessary in most ca ses. A 50 year post-injection site care timeframe represents a reasona ble and protective monitoring peri od for most GS sites based on a review of research studies, industry reports, and existing environmental programs, and evaluation of
p ublic comments. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24948EPA believes that a 50-year defa ult post-injection site care timeframe, as required at §146.93(b)(1), is not overly burdensome, does not exaggerate the risks associated with GS, is consistent with other environmental programs, and sufficiently protects USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Rule Provision: 146.93(c)

EPA Proposal: (c) Notice of intent for site closure. Th e owner or operator must notify the Director at least 120 days before site closure. At this time, if any changes have been made to the original pos t-injection site care and site closure
p lan, the owner or operator must also provide the revised plan. At the discretion of the Director, a shor ter notice period may be allowed.

GWPC Recommendations: No recommendation

Rationale: Need for site-specific c onsiderations and use of data

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Rule Provision: 146.93(d)

EPA Proposal: (d) After the Director has au thorized site closure, the owner or operator must plug all monitoring wells in a manner which will not allow movement of injection or formation fluids that e ndangers a USDW.

GWPC Recommendations: No recommendation

Rationale: Need for site-specific c onsiderations and use of data

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: EPA Proposal: (e) Once the Director has aut horized site closure, the owner or operator must submit a site closure repor t within 90 days that must thereafter be retained at a location designated by the Director. The re port must include:

(1) Documentation of appropriate inje ction and monitoring well plugging as specified in § 146.92 and para g raph (c) of this section. The owner or operator Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24949

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24950

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24951must provide a copy of a survey plat which has been submitted to the local zoning authority designated by the Dire ctor. The plat must indicate the location of the injection well relative to permanently surveyed benchmarks. The owner or operator must also submit a copy of the plat to the Regional Administrator of the appropr iate EPA Regional Office;

GWPC Recommendations: (e) Once the Direct or has authorized site closure, the owner or operator must submit a site closure report within 90 days after completion of all closure opera tions. The report must include:

(1) Documentation of appropriate inje ction and monitoring well plugging as specified in §146.92 and paragraph (c) of this section. The owner or operator must provide a copy of a survey plat wh ich has been submitted to the local zoning authority designated by the Director . The plat must indicate the location of the injection well(s) relative to permanently surveyed benchmarks. The owner or operator must also submit a copy of the plat to the Regional Administrator of the appropriate EPA Regional Office;

Rationale: What is the retention period? Many other programs have a three year limit for retention of records. EPA is th e steward of information at this point of the project, not the owner or operator.

Response: The GS regulation at §146.93(g) requires the owne r or operator to record a notation on the deed to the facility prope rty or other similar document examined during a title search that the land has been used to sequester CO2 on the deed to the facility property at the time of site closure.

Regarding record retention, EPA has clarified the recordkeeping requirements in the final GS rule, which includes requirements that well plugging repor ts, as required at §146.92(d) , post-injection site care data, as required at §146.93(f), and site closure reports, as required at §146.93(h), must be kept by the owner or operator for ten years af ter site closure. EPA believes that longer record retention times for GS wells are appropriate and necessary for the post-inj ection and site closure period to ensure that data are available to support non-endangerm ent demonstrations and to addre ss any concerns that may arise following site closure. This data w ill also support EPA's review of proj ect data as part of the adaptive rulemaking approach.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: EPA Proposal: (2) Documentation of appropriate notification a nd information to such State, local and tribal authorit ies as have authority over drilling activities to enable such State and local authorities to impose appropriate conditions on subsequent dr illing activities that may penetrate the injection and confining zone(s); and

(3) Records reflecting the nature, compos ition and volume of the carbon dioxide
stream.

GWPC Recommendations: No recommendation Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24952Rationale: Need for site-specific considerations and use of data

Response: The GS regulation at §146.93(g) requires the owne r or operator to record a notation on the deed to the facility prope rty or other similar document examined during a title search that the land has been used to sequester CO2 on the deed to the facility property at the time of site closure.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: Rule Provision: 146.93

EPA Proposal: (f) Each owner or operato r of a Class VI injection well must record a notation on the deed to the fa cility property or any other document that is normally examined during title sear ch that will in perpetuity provide any potential purchaser of the prope rty the following information:

(1) The fact that land has been used to sequester carbon dioxide; (2) The name of the State agency, local authority, and/or tribe with which the survey plat was filed, as well as the address of the Regional Environmental Protection Agency Office to wh ich it was submitted; and

GWPC Recommendations: No recommendation

Rationale: Need for site-specific c onsiderations and use of data

Response: The GS regulation at §146.93(g) requires the owne r or operator to record a notation on the deed to the facility prope rty or other similar document examined during a title search that the land has been used to sequester CO2 on the deed to the facility property at the time of site closure.

Other EPA Comment Codes and Descriptions: 4730 2.7.3 Reporting associated with closure and
p ost-injection site care; 5300 2.8.3 Site closure activities (40 CFR 146.93) Comment: EPA Proposal: (3) The volume of fluid inject ed, the injection zone or zones into which it was injected, and the peri od over which injection occurred.

(g) The owner or operator must retain fo r three years following site closure, records collected during the post-inject ion site care period. The owner or operator must deliver the records to th e Director at the conclusion of the retention period, and the records must thereafter be retained at a location designated by the Director for that purpose.

GWPC Recommendations: No recommendation

Rationale: Need for site-specific c onsiderations and use of data

Response: The GS regulation at §146.93(g) requires the owne r or operator to record a notation on the deed to the facilit y propert y or other similar doc ument examined durin g a title search that the land has Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24953

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24954b een used to sequester CO2 on the deed to the facility property at the time of site closure.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: Rule Provision: 146.94(b)

(b) If the owner or operator obtains evid ence that the injected carbon dioxide stream and associated pressure front may cause an endangerment to a USDW, the owner or operator must:

(1) Immediately c ease injection; (2) Take all steps reasonably necessary to identify and characterize any release; (3) Notify the Director within 24 hours; and (4) Implement the emergency and remedial response plan approved by the Director.

GWPC Recommendations: (b) If the owner or operator obtains evidence that the injected carbon dioxide st ream, displaced formation fluids or associated
p ressure front endangers a USDW, the owner or operator must:

(1) Immediately c ease injection; (2) Take all steps reasonably necessary to identify and characterize the endangerment posed; (3) Notify the Director or the designat ed representative within 24 hours of becoming aware of the endangerment; and (4) Implement the emergency and remedial response plan approved by the Director.

Rationale: The GWPC felt the notification period needed clarif ication since it did not specify when the clock began to run for the 24 hour notice period. Further, it was felt that notification of someone representing the Director would also constitute appropriate notice.

Response: After consideration of comments, EPA has finalized the rule language in §146.94(b) as
p roposed. In the introductory section of §146.94(b), EPA clarifies that the pressure front, as defined in §146.81, is a zone where the pressure differential is suff icient to cause the moveme nt of injected fluids or formation fluids into a USDW. Therefore, displ aced formation fluids are im plicitly included in the requirements for §146.94. EPA also clarif ies that owners or operators must take action when the CO2 stream or pressure front may caus e endangerment. In order to preven t the endangerment of USDWs, as required under §1421 of the SDWA, EPA expects the ow ner or operator to act preemptively and not wait until endangerment has occurred. This language is consistent with exis ting UIC requirements for other well classes and EPA’ s authority under the SDWA.

Regarding changes to the language in §146.94(b)(1), EPA clarifies that the Agency expects that owners or operators take care not to damage the well when ceasi ng injection under §146.94(b)(1). At §146.94(b) (2), EPA is maintaining the requirement to “characterize the release.” In order to prevent the endan g erment of USDWs, as required under §1421 of the SDWA, EPA expe cts the owner or operator to Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24956act preemptively and not wait until endangerment has occurred. This la nguage is consistent with existing UIC requirements for other well classe s and EPA’s authority under the SDWA.

Concerning commenters’ suggestions for §146.94(b)(3), EPA clarifies that the 24 hours begins when the owner or operator obtains evidence of possible endangerm ent. Note that the defini tion of the Director in 40 CFR 144.3 includes the Director’s authorized representative. EPA believes the rule language is clear on this requirement.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: EPA Proposal: (c) The Director may allow th e operator to resume injection prior to remediation if the ow ner or operator demonstrates that the injection operation will not endanger USDWs.

(d) The owner or operator must notify the Director and obtain his approval prior to conducting any well workover.

GWPC Recommendations: Support the proposed EPA language for (c)

(d) The owner or operator must notify the Director prior to conducting any well workover in response to any case of endangerment.

Rationale: In critical situations, time spent obtaining approval could adversely affect the ability to conduc t operations or increase the level of endangerment.

Response: Since proposal, EPA has modified the final regulatory language at §146.94(d) to clarify what constitutes a workover to address a well failure (whi ch invokes remedial actions ) and what constitutes a maintenance-type workover. For maintenance-type workovers (i.e., those that are scheduled in advance), the owner or operator must notify a nd gain approval from the Director prior to beginning the workover. In the final GS regulation, EPA has moved this re quirement to the reporting requirements at §146.91(d) to clarify its intent.

Regarding concerns that notification could delay responses, EPA clarifies th at the GS rule, at §146.94 (b), describes procedures owners or operators must take in em ergency situations. Specifically, upon determining that there is a problem with the well that may endanger a USDW, the owner or operator must first cease injection, then take all steps reas onably necessary to identify and characterize any release, notify the Director, and implement the approved emergency and remedial response plan, which may include a well workover. EPA believes that ceasing injection (which the owner or operator would do immediately and before notifying the Director) is the action necessary to prevent or mitigate endangerment of USDWs as required under the SDWA.

Comment: Rule Provision: 146.81 Applicability.

EPA Proposal: (a) Th is subpart establishes crit eria and standards for under g round in j ection control pro g rams to re g ulate Class VI carbon dioxide Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24957

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 24965geologic sequestration injection wells.

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment. For additional information on EPA's final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87

EPA Proposal: 7. Logging, sampling, and te sting prior to injection well operation

(a) During the drilling and c onstruction of a Class VI injection well, the owner or operator must run appropriate logs, surv eys and tests to determine or verify the depth, thickness, porosity, permeabilit y, and lithology of, and the salinity of any formation fluids in, all releva nt geologic formations to assure conformance with the injection well construction requirements under § 146.86, and to establish accurate baseline data ag ainst which future measurements may be compared. The owner or operator must s ubmit to the Director a descriptive report prepared by a knowledgeable log anal yst that includes an interpretation of the results of such logs and tests. At a minimum, such logs and tests must include:

GWPC Recommendations: (a) During the dril ling and construction of a Class VI injection well, the owner or operator mu st run appropriate logs, surveys and tests to determine or verify the dept h, thickness, porosity, permeability, and lithology of, and the salinity of any formation fluids in, all relevant geologic formations to assure conformance w ith the injection well construction requirements under §146.86, and to establish accurate baseline data against which future measurements may be compare d. The owner or operator must submit to the Director a descriptive report prepared by a knowledgeable log analyst that includes an interpretation of the results of such logs and tests. The Director may require such logs and tests as may be needed after taking into account the availability of similar data in the ar ea of the drilling site, the construction
p lan, and the need for additional informati on that may arise from time to time as the construction of the well progresse s and these may include the following:

Rationale: In well defined areas, thes e evaluations are frequently unnecessary. The director should have discretion to select the appropriate requirements necessary to ensure sufficient baseline da ta and information are available. For example, in an area wher e a number of wells are bei ng drilled, the logging of surface hole yields little usef ul additional information.

In particular, this chan g e would allow the Director to reduce the requirements Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29176when multiple wells are installed for a project.

Response: EPA believes that the logging and testing requi rements in the GS rule are appropriate and necessary. The requirements at §146.87 stem from ex isting knowledge and practic es in place for other injection well classes and within th e oil and gas industry, and are tailored to the special characteristics of CO2 injection for GS.

EPA is developing guidance on monitoring and testing that will describe recommended tests and
p rocedures to assist owners/operators and Directors in evaluating the requirements for pre-operational logging and testing under §146.87. Th is guidance will be avai lable on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

EPA clarifies that §146.87(b) provides some flexibil ity. EPA notes that §146.87(b) allows information on cores from nearby wells to be s ubmitted if the owner or operator can demonstrate that core retrieval is not possible and that cores from nearby wells are representative of conditi ons at the GS well. EPA clarifies that, at a minimum, reports on cores of in jection zones and confini ng zones, and samples of formation fluids must be submitte d. Section 146.87(b) gives the Director authority to require the owner or operator to core other formations in the borehole if necessary to provide sufficient geologic information to verify that the site is suitable for GS.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: EPA Proposal: (1) Deviation checks during drilling on all holes constructed by drilling a pilot hole which are enlarged by reaming or another method. Such checks must be at sufficiently frequent intervals to determine the location of the borehole and to assure that vertical avenues for fluid movement in the form of diverging holes are not cr eated during drilling; and

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment; th e final rule retains the requirements for deviation checks required at §146.87(a)(1). EPA adds that the Director would have discretion to approve a plan without deviation checks that addresses circumstances where these tests may not be practical or useful, such as those mentioned by the commenter. EP A encourages owners or operators to discuss these situations with the Director when planni ng the deviation testing.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(a)

EPA Proposal: (2) Before and upon installation of the surface casing:

GWPC Recommendations: Support the proposed EPA lan g ua g e. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29177

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29178Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment; the final rule retains the requirements for logging and testing prior to and upon inst allation of surface casing.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: EPA Proposal: (i) Resistivity, spontaneous potential, and caliper logs before the casing is installed; and

GWPC Recommendations: (i) Resistivity, s pontaneous potential, and caliper logs before the casing is installed; and

Rationale: After a few wells are drilled in an area, these evaluations are frequently unnecessary and yi eld little new information.T his is an example of why it is appropriate to make this a discretionary rather than mandatory requirement. The proposed re vision to 146.87(a) would give the Director the necessary discretion.

Response: EPA disagrees that the requireme nts for logs, surveys, and test s are excessive or duplicative. All logs, surveys, and tests listed at §146.87(a) are necessary to verify information about the injection and confining zones and ensure that the well is being drilled and cased as approved, and has mechanical integrity. EPA notes that the Dire ctor has the discretion at §146.87(a)(5 ) to approve alternative methods that provide equivalent or better information.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: EPA Proposal: (ii) A cement bond and variable density log, and a temperature log after the casing is set and cemented.

GWPC Recommendations: (ii) A cement bond and variable density log, and a temperature log after the casing is set and cemented.

Rationale: Unusual to run these logs in a surface hole due to uniformity of shallow geology. This is an example of w hy it is appropriate to make this a discretionary rather than mandatory requirement. The proposed revision to 146.87(a) would give the Director the necessary discretion.

Response: As described above, EPA disagrees that the re quirements for logs, surveys, and tests are excessive or duplicative. All logs , surveys, and tests listed at §146.87(a) are necessary to verify information about the injection and c onfining zones and ensure that the well is being drilled and cased as approved, and has mechanical integrity. EPA notes th at the Director has the discretion at §146.87(a)(5) to approve alternative methods that provi de equivalent or better information. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29179

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29180EPA clarifies that in the final GS rule, §146.87(a)(2)( ii) reads as follows: "A cement bond and variable density log to evaluate cement quality radially, and a temperature log after the casing is set and cemented."

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: EPA Proposal: (3) Before and upon installation of the long string casing:

GWPC Recommendations: Support the proposed EPA language.

Rationale: Agree with EPA’s rationale.

Response: EPA acknowledges the comment; the final rule retains the requirements for logging and testing prior to and upon installa tion of the long string casing.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: EPA Proposal: (i) Resistivity, spontaneous potential, porosity, caliper, gamma ray, fracture finder logs, a nd any other logs the Director requires for the given geology before the casing is installed; and

GWPC Recommendations: Support the proposed EPA language.

Response: EPA acknowledges the comment; the final rule retains the require ments for the logs and tests required at §146.87(a)(3).

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: EPA Proposal: (ii) A cement bond and variable density log, and a temperature log after the casing is set and cemented.

GWPC Recommendations: (ii) Cement evaluation logs after the casing is set and cemented to evaluate cement quality wi th sufficient radial resolution to identify channels or missing cement.

Rationale: Acceptable to specify basic logging requirements, however, special logs should not be specified. Any other information from the area should be drawn on. Provides more flexibility to select the appropriate log to demonstrate adequate cement bond.

Response: EPA agrees with the suggested change. In the final GS rule, §146.87(a)(2)(ii) reads as follows: "A cement bond and variable densit y lo g to evaluate cement qualit y radiall y , and a temperature Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29181

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29182

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29183log after the casing is set and cemented."

EPA believes that a minimum suite of logs and tests is necessary at al l GS wells. All logs, surveys, and tests listed at §146.87(a) are necessary to verify information about the injection and confining zones and ensure that the well is being dril led and cased as approved and has me chanical integrity. EPA adds that, should alternative methods be shown to provide equivalent or better information or if site-specific conditions and risk factors dictate that other logs are necessary, the Director has the discretion at §146.87(a)(5) to require further logs and tests if n ecessary and to approve alternative methods that
p rovide equivalent or better information.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: EPA Proposal: 146.87(a)(4)

(4) A series of tests designed to dem onstrate the internal and external mechanical integrity of inject ion wells, which may include:

(i) A pressure test with liquid or gas; (ii) A tracer survey such as oxygen-activation logging; (iii) A temperature or noise log; (iv) A casing inspection log, if required by the Director; and

(5) Any alternative methods that provide equivalent or bette r information and that are required of and/or approved of by the Director.

GWPC Recommendations: (4) Test(s) designe d to demonstrate the internal and external mechanical integrity of in jection wells, which may include:

(i) A pressure test with liquid or gas; (ii) Diagnostic tools such as oxygen-activation logging; (iii) A temperature or noise log; and (iv) A casing inspection log.

(5) Accept the EPA language and numbering.

Rationale: Technical and gr ammatical corrections

In (iv), "if required by the Director" is unnecessary.

We interpret that (5) a pplies to 146.87(a)

Response: EPA agrees with the commenter about the word ing of the casing inspection log requirement at §146.87(a)(4) and made the suggested change to im prove clarity. In the fina l regulation, §146.87(a)(4) (iv) does not include the phrase, “if required by the Director.” Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29184

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29185Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule provision: 146.87(b)

EPA Proposal: (b) The owner or operator must take and submit to the Director whole cores or sidewall cores of the in jection zone and confining system and formation fluid samples from the inject ion zone(s). The Director may accept cores from nearby wells if the owner or operator can demonstrate that core retrieval is not possible and that such cores are representative of conditions at the well. The Director may require the owner or operator to core other formations in the borehole.

GWPC Recommendations: (b) The owner or ope rator must submit to the Director a report describing whole cores or sidewall cores representative of the injection zone and confining system and formati on fluid samples from the injection zone(s). The Director may accept data from cores and fluid samples from nearby wells if the owner or operator can demonstr ate that such data are representative of conditions in the wellbore.

Rationale: The information required should be sufficient to properly describe the injection and confining zones.

Response: EPA clarifies that it is not the Agency's in tent that physical core s be submitted to the Director. In the final GS rule, EPA has revised the first sentence of §146.87(b) to read as follows: "The owner or operator must take whole cores or sidewall cores of the in jection zone and confining system and formation fluid samples from the injection zone(s), and must submit to the Director a detailed report
p repared by a log analyst that includes: well log an alyses (including well logs), core analyses, and formation fluid sample information...."

EPA believes that logs and tests must be performed on each well drilled regardless of existing information about the area to account for the comp lexity of CO2 injection well construction and the buoyancy of CO2. Existing lithologic and geologic info rmation may lack the details needed for sitespecific well design and the geology needed to support protection of USDW s from endangerment.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: EPA Proposal: (c) The owner or operator must record the fluid temperature, pH, conductivity, reservoi r pressure and the static fluid level of the injection zone(s).

GWPC Recommendations: (c) Prior to in jection well operation, the owner or operator must record the formation te mperature, formatio n fluid pH and conductivity, and reser voir pressure of the injection zone(s).

Rationale: Technical correcti ons. Reservoir pressure and static fluid level are redundant parameters.

Response: EPA disa g rees that "reservoir pressure" and "stati c fluid level" are redundant parameters. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29186Although the static fluid level is equal to the bottom hole pressure, this may not always be identical to the reservoir pressure. Additionally, measuring the static fluid level provides additional assurance that the reading is accurate (or, provides the needed information in cases where a good reading is not obtained). In addition, a static flui d level measurement provides inform ation regarding the proximity to USDWs that need protection afforded to them.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: EPA Proposal: (d) At a minimum, the ow ner or operator must determine or calculate the following information c oncerning the injection and confining zone(s):

(1) Fracture pressure; (2) Other physical and chemical characteris tics of the inject ion and confining zones; and (3) Physical and chemical characteristi cs of the formation fluids in the injection zone.

GWPC Recommendations: Delete all

Rationale: With the excepti on of calculating fracture pressure, the requirements of this section appear redundant to ot her requirements of prior sections. Recommend moving injection pressure to old (e), now renumbered as (d).

(2) and (3) are also too vague.

Response: EPA believes that the requirement to provide information on the injection and confining zones in §146.87(d) is warranted, and that the rule provides flexibility to account for the variety of geologic conditions that may be encountered at GS sites.

EPA is developing guidance on monitoring and testing that will describe recommended tests and
p rocedures to assist owners/operators and Directors in evaluating the requirements for pre-operational logging and testing under §146.87. Th is guidance will be avai lable on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: EPA Proposal: (e) Upon completion, but prior to operation, the owner or operator must conduct the following tests to veri fy hydrogeologic characteristics of the injection zone:

(1) A pump test; or (2) Injectivity tests.

GWPC Recommendations: (d) At an y time prior to in j ection well operation, the Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29187

Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29188owner or operator must determine fracture pressures of the injection and confining zones and conduct tests to verify hydrogeologic and geomechanical characteristics of th e injection zone, e.g., injectivity tests.

Rationale: Allows the use of information such as leak off tests conducted during the drilling operation.

Delete (1)

It was felt that Geomechan ical properties were at least as important as hydrogeologic characteristics.

The results of a pump test (pumping fluid from the well) has no relevance for an injection well.

If current (d) is deleted as reco mmended, this would become (d)

Response: EPA clarifies that the owner or operator has the optio n of using pump tests or injectivity tests depending on which would provide the most valuable information based on site-specific conditions. Further, EPA disagrees that pump tests are irrelevant to determin ing injection zone properties. Depending on the characteristics or depth of knowledge of the confining and injection zone formations,
p ump tests may be necessary to prove that no hydrauli c connection exists between the injection zone and a USDW.

EPA is developing guidance on monitoring and testing that will describe recommended tests and
p rocedures to assist owners/operators and Directors in evaluating the requirements for pre-operational logging and testing under §146.87. Th is guidance will be avai lable on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3866 2.3.3.3 Logging and testing requirements (40 CFR 146.87) Comment: Rule Provision: 146.87(f)

EPA Proposal: (f) The owner or operator must provide the Director with the opportunity to witness all logging and testing by this subpart. The owner or operator must submit a schedule of such ac tivities to the Dire ctor 30 days prior to conducting the first test and submit any changes to the schedule 30 days
p rior to the next scheduled test.

GWPC Recommendations: (e) The owner or ope rator must provide the Director with the opportunity to witness all logging and testing by this subpart. The owner or operator must submit a schedule of such activities to the Director upon spudding the well and submit any changes to the schedule 48 hours prior to the scheduled
test.

Rationale: The changes reflect the realities of flexible rig schedules and are fully consistent with current Class II requirements and practices. Commenter Name: Michel Paque Letter ID: 0259 Commenter Or g anization: Ground Water Protection Council Comment ID: 29189If current (d) is deleted as r ecommended, this would become (e)

Response: EPA disagrees that the 30-day notificati on requirement is unreasonable. The 30-day notification mirrors the current requirement for logging and testing of new Class I wells, as described in §146.66. Acknowledging the developing nature of CO2 GS, EPA believes that involvement by the
p ermitting authority in each projec t will provide much needed field data for assurance of USDW
p rotection from endangerment and will help update a nd refine the permitting pr ocess. Adequate timing of notification will ensure the Director's ability to be involved.

Other EPA Comment Codes and Descriptions: 4110 2.4.1.1 Injection pressure limitations Comment: C. Pressure management

[FR p. 43538, §146.88(a)] EPA has proposed to a dopt an injection pressure limit equal to 90 percent of the fr acture pressure in the in jection zone. This is a high number, and there will be cases where it is prudent to lo wer limits. Since injection is likely to take place in dive rse geologic settings, we believe that those limits should be calculated individually, taki ng into account a number of geologic factors each time, which we atte mpt to incorporate in the proposed language below. Nonetheless, we believe that EPA should maintain a maximum upper limit (equal to or less than 90 percen t of the fracture pressure in the injection zone), so as to avoid cases where studies might appear to support higher limits that would not be advisabl e. We also consider the "Except during stimulation" qualifier as confusing and creating a loophole and we urge that it be removed. Finally, the pressure limi ts themselves should refer to the confining zone and not the injection zone . We offer the following language as a starting point:

"The owner or operator must ensure that injection pressure doe s not exceed [90]
p ercent of the fracture pressure of the confining zone. The owner or operator must comply with a maximum injection pre ssure limit approved by the Director and specified in the permit. In approving a ma ximum injection pressure limit, the Director must consider the results of well tests and, where appropriate geomechanical or other studies, that asse ss the risks of tensile failure and shear failure. Limits shall be calculated so as to assure that pressure will avoid initiation or propagation of fractures in the confining zone or cause otherwise non-transmissive fa ults transecting the confining zone to become transmissible. In no case may injection pr essure cause movement of injection or formation fluids that endangers a USDW."

The maximum upper limit should not be used as a default in place of tests and studies that should be used to establish appropriate limits for specific sites - we urge EPA to ensure that this is built into the rule language. The consideration of both tensile and shear failure is necessary in carrying out a rigorous evaluation, in our view, as is th e requirement not to cause otherwise non-transmissive faults transecting the confining zone to become transmissible. We also urge EPA to compile a list of qua lity criteria against which the results of the mentioned tests and studies will be evaluated - these need to be transparent and capable of screenin g adequate tests from inadequate ones. Commenter Name: David Hawkins Letter ID: 0272 Commenter Or g anization: Natural Resources Defense Council Comment ID: 24078Pressure limits should also ensure that no significant risks from seismicity are
p osed, and EPA should incorporate appropr iate language in the setting of
p ressure limits.

We further believe that the established phras ing "so as to assure that", used in Class II, is preferable to other formulat ions such as "with a reasonable degree of certainty". We also believe that the proposed rule’s language on movement of fluids "that endangers a USDW" is more pr otective and preferable to the wording "into a USDW", and preferable to refe rences to §144.12(a). As mentioned above, the rule should be drafted to assure no releases to the atmosphere as well.

Response: EPA disagrees with the suggesti on that injection pressure be set at less than 90 percent of fracture pressure. EPA believes that a lower pressure limitation may not allow for sufficient volumes of CO2 to be transmitted away from the well and into the injection formation. EPA acknowledges that there may be circumstances where a lower pressure limitation may be appropriate; in such cases, the Director has the authority, at §146.88, to set a lower pressure limit in the opera ting permit. EPA believes that the 90 percent requirement allo ws the consideration of site-sp ecific circumstances and provides a satisfactory margin of safety during well operation.

EPA clarifies that injecti on pressure limit for each GS project will be based on site-specific conditions, and be informed by data on the in jection and confining zones. Duri ng injection, the pressure in the injection zone must not exceed 90 perc ent of the fracture pressure of th e injection zone, as specified at §146.88(a). The fracture pressure (and, therefore, th e injection pressure) ar e based on site-specific geologic and geomechanical data collected during the site charact erization process required at §146.82. Tests are available and have been used by injection well operators, e.g., Class I operators, to measure fracture pressure. Examples include the step-rate test , in-situ stress tests, and a combination of a long spaced sonic log with laboratory m easurement of the mechanical propert ies of cores. To meet the GS requirements, the permitting authority must set the injection pressure limi t at 90 percent of this value.

The Director will review geologic, hydrogeologic, and geomechanical information submitted by the owner or operator in setting permit conditions. If, ba sed on this information, a lower pressure limitation is appropriate, the Director has th e authority to set a lower limit in the operating permit. EPA clarifies that fracturing of the confining zone during injection and/or stimulation is also prohibited at §146.88(a).

The final rule provides for the use of stimulation. EPA believes that stimul ation is important for enhancing formation injectivity, provi ded it is performed in a manner that maintains the integrity of the confining zone. All stimulation mu st be approved by the Director. Ow ners or operators must submit a
p roposed stimulation program as part of the permit applicati on under §146.82(a)(9); the plan must demonstrate that any stimulation act ivities will not compromise the in tegrity of the confining zone. The Director will evaluate the owner or operator's proposed stimulation plan in the context of all information about the site, and the owner or operator must perform stimulat ion only as approved.

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators in meeting the requirements of §146.82 a nd to assist directors in eval uating permit applications. The guidance will describe recommended approach es for characterizing the regional geology and hydrogeology of a proposed site and performing th e necessary geochemical, geomechanical, and geophysical analyses of the inject ion and confining zone. EPA is al so developing guidance for primacy agencies that will include recommended approaches for evaluating owner or operator-submitted data in setting permit conditions. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: D. Closure

[FR p. 43540, §146.93(b)] EPA has proposed an arrangement whereby the operator continues to monitor the site for a mini mum of 50 years after the cessation of injection, unless the operator can demonstrate to the satisfaction of the Director that the project no longer poses an endangerment to USDWs and that the CO2 plume and pressure front have stabilized.

While 50 years is not a number that will apply in all cases and projects, we do believe that it is appropriate as a default at today’s level of our understanding and operational e xperience with GS. The option that operators have under the current proposal to obtain appr oval for a lower number, based on actual project performance, should be suff icient to deal with situations where 50 years can be demonstrated to be unne cessarily long. Along the same lines, there might be situations where 50 years would not suffice, and where the Director should require a longer peri od, as per the current proposal. In assessing non-endangerment to USDWs and plum e/pressure front stabilization, we believe that the EPA should be far more specific in its require ments. We offer the following language as a suggested revision to §146.93(b):

"(b) The owner or operator shall monito r the site following the cessation of injection.

(1) The owner or operator shall continue to conduct monitoring as specified in the Director-approved post-injection site care and site closure plan for at least 50 years following the cessation of injection or until closure is authorized.

(2)If the owner or operator can demonstrat e to the satisfaction of the Director before 50 years, based on/pursuant to the criteria in (b), that the geologic sequestration project does not and is not expected to pose an endangerment to USDWs or result in releases to the at mosphere, the Director may approve an amendment to the post-injection site care and site closure plan to reduce the frequency of monitoring or may authorize site closure before the end of the 50- year period.

(3) Prior to authorization for site closure, the owner or operator must demonstrate to the Director, based on m onitoring, other site-s pecific data, and modeling that is consistent with site performance, that no additional monitoring is needed to assure that the geologic sequestration project does not and is not expected to pose an endangerment to USDWs or any release to the atmosphere. The owner or operator must demonstrate, based on the current understanding of the site, including monitoring data and mode ling, all of the following: (i) the magnitude and extent of the project f ootprint (CO2 plume and the area of elevated pressure); (ii) the location of the detectable CO2 plume; (iii) that there is no significant leakage of either CO2 or displaced formation fluids that is endangering USDWs or creating a potenti al release to the atmosphere; (iv) Commenter Name: David Hawkins Letter ID: 0272 Commenter Or g anization: Natural Resources Defense Council Comment ID: 24079that the injected or displ aced fluids are not expected to migrate in the future in a manner that encounters a potential le akage pathway into a USDW or to the atmosphere; (v) that the injection wells at the site completed into or through the injection zone or c onfining zone are plugged a nd abandoned in accordance with these requirements; and (vi) any re maining project monito ring wells at the site are being managed by a person and in a manner acceptable to the Director.

(4) If such a demonstration cannot be ma de after the 50-year period, the owner or operator must submit to the Director a plan to continue post-injection site care."

Response: EPA agrees that a 50 year post-injection site care timefram e represents a reasonable and
p rotective post-injection site moni toring period for most projects and available data, including data submitted by commenters, do not suppor t a different default timeframe. EPA bases this on a review of research studies, industry reports, and existing en vironmental programs, and evaluation of public
comments.

However, EPA recognizes th at there may be sites where the 50 year post injection site care timeframe may be either not appropriate or more burdensome than necessary based on site-specific conditions. For this reason, the GS rule offers owners or operators flexibilit y regarding the duration of the PISC timeframe by: (1) allowing the Direct or discretion to shorten or lengt hen the PISC timeframe during the
p ost-injection period based on site-specific data, pursuant to requi rements at §146.93(b); or (2) affording the Director discretion to allow a Class VI well ow ner or operator to demonstr ate, during the permitting
p rocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe for
p ost-injection site care will be necessary in most cases. The default 50 year post-injection site care timeframe represents a r easonable and protective monitoring peri od based on a review of research studies, industry reports, and exis ting environmental programs, and evaluation of public comments.

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts.

In response to comments to be more specific, EP A believes §146.93 is sufficiently specific for the
p urposes of protecting USDWs. Furthermore, the commente r ’s proposed language regarding released CO2 emissions into the air are outside the scope of this rulemaking and EPA’s authority under the SDWA.

Other EPA Comment Codes and Descriptions: 2048 1.5.2.4 Oppose Class VI/ Support Class V experimental technology well; 2200 1.6.4 Other formation types Comment: To implement this approach, sect ions 144.6(f), 144.80(f), 146.5(f) and the definition of sequestration in 146.81 should be revised. The proposed 144.15 Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25308p rovision that the construction, ope ration or maintenance of any nonexperimental Class V GS well is prohibited should be re tained, but only with the understanding that this prohibition is not in tended to limit the size or scale of any experimental GS operation.

"Class VI. Wells used for geologic seque stration but not including those wells used for geologic sequestration that are regulated under another Class. Wells used for geologic sequestration in basalts, coal seams, salt caverns or shales are regulated under Class V as experimental wells unt il such time as the Administrator establishes separate requireme nts by rule for the specific type of formation or determines, following public notice and opportunity for comment, that wells used for geologic sequestrati on of carbon dioxide streams into the specific type of formation should be regulated under another class."

Response: The text at 144.15 is retained in the fina l regulation; the construction, operation or maintenance of any non-experimental Class V GS well is pr ohibited under the final rule. The final rule contains tailored requirements fo r Class VI wells to ensure that GS projects are permitted, sited, constructed, operated, and closed in a manne r that protects USDWs from endangerment.

As described above, EPA clarifies that the final GS rule does not categorically preclude injection of CO2 into any formation types. EPA clarifies that e xperimental research projects will continue to be regulated as Class V experimental technology wells as long as they rema in of an experimental nature.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: 2. Non-interference principle

EPA notes in the preamble (page 43506), "i t is...possible that multiple owners or operators will be inj ecting CO2 into formations that are hydraulically connected and thus the elevat ed pressure zones may inte rsect or interfere with each other." We have agreed that this possibility should be addressed through a revision to the regulations. Until more co mprehensive approaches to basin-scale management are developed and based on the proposed definition of "pressure front", we recommend the adoption of the following addition to §146.94:

"(e) If an owner or operator obtains evid ence that a pressure front associated with one geologic sequestration project inters ects or will more likely than not intersect the pressure front or area of re view associat ed with another project, the owner or operator obtaining such evid ence must notify the Director. The Director shall notify the owner or opera tor of the other geologic sequestration
p roject. If the Director determines that the pressure front associated with one
p roject interferes or will more likely than not interfere with the ability of another project to comply with the term s of its permit(s), the Director may require the owners or operators of the interfering or potentially interfering
p rojects to modify operations as neces sary to mitigate or avoid such interference. Such modifications may also include modifications mutually agreed upon by the respective owners and operators and approved by the Director." Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25309Response: EPA agrees with the commenter that there are a variety of factors that may affect the need for emergency and remedial response at GS sites. The Agency believes that a site-specific emergency and remedial response plan that is informed by required site characte rization data (per §146.82), modeling for AoR evaluations and reevaluations (per §146.84), and monitoring data (per §146.90) will appropriately address commenter concerns regarding th e potential impacts of mu ltiple GS projects. EPA has added a requirement at §146.94(d) that owners or operators must revi ew their emergency and remedial response plan within one year of an AoR reevaluation required under 146.84 or following significant changes to the facility. Subsequently, the owners or operato rs must submit an amended plan or demonstrate to the Director that no amendment to the plan is needed based on the AoR reevaluation or any significant changes made to the facility.

EPA also encourages owners or operators and pe rmitting authorities to communicate planned GS activities during initial permitting activities to maximize coordination and minimize pressure interference. If a permit applicant (or the permitti ng authority) is aware of pending GS projects near a
p roposed well, the AoR delineation performed pursu ant to 146.84 should account for the impacts of multiple owners and operators injecting within a single basin. EPA expects that, where multiple operators are involved, the Director will not approve modeling that does not account for changes that may result from all injection operations.

EPA expects that changes within the AoR, such as the addition of new well s or projects that could
p otentially interfere with a GS project, would be identified as part of the AoR reevaluations required at §146.84(e) and would need to be addr essed in a revised emergency and remedial response plan. EPA is developing guidance on the development and implementa tion of project plans fo r GS sites, including emergency and remedi al response plans.

Other EPA Comment Codes and Descriptions: 3420 2.2.2.1 Scope of the inventory process (e.g., reliance on publicly available in formation, depth of wells) Comment: 6. Area of review and corrective action requirements

In proposed §144.55(a) the rule would require Class I, II (other than existing), III or VI permit applicants to identify the location "of all known wells within the injection well’s area of review which penetrate the injection zone" or, in the case of Class II wells operating over the fracture pressure of the injection formation, "all known wells within the area of review penetrating formations affected by the increase in pressure."

Since injection in deep saline formations will result in an area of elevated
p ressure (above the original reservoir pressure) that will be larger than the CO2 plume and could conceivably affect overlying or underlying formations, we have agreed that the requirement for Cl ass II wells operating above the fracture
p ressure should also apply to Class VI wells. This would help prevent the unwanted migration of reservoir fluids from the injection zone as a result of the pressure increase. We therefore recommend that §144.55(a) be revised to read as follows, with revisions shown in blue:

"(a) Coverage. Applicants for Class I, II, (other than existing), or III, injection well permits shall identify the location of all known wells within the in

j ection well's area of review which penetrate the in j ection zone. In the case Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25314of Class II wells that operate over th e fracture pressure of the injection formation, applicants shall also identify the location of all known wells within the area of review penetrating formations affected by the increase in pressure. For such wells which are improperly sealed, completed, or abandoned, the applicant shall also submit a plan consis ting of such steps or modifications as are necessary to prevent movement of fl uid into underground sources of drinking water (‘‘corrective action’’) . Where the plan is adequate, the Director shall incorporate it into the permit as a condition. Where the Director’s review of an application indicates that the permittee’ s plan is inadequate (based on the factors in §146.07) , the Director shall require the applicant to revise the
p lan, prescribe a plan for corrective action as a condition of the permit under
p aragraph (b) of this section, or deny the application. The Director may disregard the provisions of §146.06 (Ar ea of Review) and §146.07 (Corrective Action) when reviewing an application to permit an existi ng Class II well. Applicants for permits for Class VI well s [or for wells in other classes that are used for geologic sequestration and do not meet the criteria for §144.6(b) (4)][FN3] shall identify the location of al l known wells within the area of review
p enetrating the injection zone and all know n wells within the area of review which penetrate formations affected by the pressure front and shall perform corrective action as specified in §146.84."

3/ The undersigned, except NRDC whic h does not support the Group’s proposed bright line definition and language for §144.6(b)(4) (see MSG letter of Dec. 23, 2008), believe that this clause in brackets should be included.

Response: The final rule leaves §144.55 unchanged from the existing UIC requirements; i.e., Class VI wells are not addressed in this provision. Based on its evaluation of all public comments and input on the proposed rule and NODA and Request for Commen t, EPA has made many revisions to the GS Rule. See the final rule and preamble for further discussion on EPA's final approach.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: 7. Well construction

EPA’s proposed §146.86(b)(3) woul d require the long string casing to be cemented by circulating cement to surfa ce in one or more stages. Yet that may be hard to accomplish in some cases, such as very deep wells. There are also potential disadvantages of this approach with regard to the weight of the cement column and its relation to well integrity. Sealing this annulus also eliminates an approach for monitoring the integrity of the cement in that critical interval through the primary confinin g interval and above. We recommend that EPA not make this a mandatory requirement. The requirement should also recognize that there may be other technol ogies that could be as effective as cement and centralizers, which may not be feasible in some applications; furthermore, current research and development effo rts are likely to yield additional technologies the use of which should not be foreclosed. Accordingly, we recommend the following la nguage for §146.86(b)(3): Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25315"(3) At least one long string casing, usi ng a sufficient number of centralizers, which at a minimum: must be sealed from within the injection zone upward through the overlying confining zone, and must provide adequate isolation of the injection zone and other in tervals as necessary for pr otection of USDWs using cement and/or other isolation techniques. The Director may approve the use of
p ackers or alternative isolation techniques, provided these are demonstrated to be equivalent to cement or more effectiv e to provide adequate isolation and to
p rotect USDWs."

Response: EPA does not believe that the cementing re quirements at §146.86 would prevent monitoring, operation and remediation of Class VI wells. Cementing of deep wells has been performed successfully in the past by owners or operators of Class I h azardous and Class I municipal waste disposal wells. Some of these wells, which must meet the same cementing and casing requirements as Class VI wells, are up to 12,000 feet deep and have b een successfully cemented in a ma nner that maintains integrity and allows for all required well testin g, operation, and remediation (EPA , 2001). See the discussion of Class VI well construction requirements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guida nce on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa .gov/type/groundwater/uic/w ells_sequestration.cfm.

Section 146.86(b)(3) requires that the long-string casing extend to the injection zone and be cemented by circulating cement to the surfac e in one or more stages. It doe s not, however, specify how cementing should be accomplished, and gives fl exibility to the owner or operator to propose alternate methods to
p rovide a sufficient amount of cement to meet the standard that US DWs are protected from endangerment, subject to the approva l of the Director. EPA notes that there are many potential ways to meet the requirement in deep wells, such as the use of staged cementing.

EPA also received comments from stakeholders representing states, a water association, and industry supporting this provision, saying that it provides, at a reasonable cost, co rrosion protection of the casing;
p revents undesirable migration of fl uids behind the casing; provides support to the casing; and provides multiple barriers against endangerment of USDWs.

EPA stresses that protection of US DWs is the primary mission and ma ndate of the UIC program and the
p urpose of all requirements for injection wells. A ny injection activity must be demonstrated to not endanger USDWs, regardless of their depth, and if such non-endangerment cannot be shown, then the activity will not be allowed under UIC requirements or the SDWA.

EPA recognizes concerns re garding construction of Class VI well s where the lowermost USDW is very deep. To further address comments on deep inje ction wells, the final GS rule at §146.95 includes requirements for owners or operators that seek a waiv er of the injection depth requirements. Owners or operators of wells operating under in jection depth waivers must comp ly with additional construction requirements to ensure that wells used to inject above or between USDWs are protective. See the discussion of the waiver approach in the preamble to the final GS rule for additional information.

Other EPA Comment Codes and Descriptions: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) Comment: 8. Reevaluation of the Area of Review and Revision and Maintenance of Plans

Althou g h the proposed §146.84(f) would require "reevaluation" of the aor at a Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25316"minimum" fixed frequency of ten year s or "when operational and monitoring conditions warrant," the specific langua ge of §146.84 runs the risk that revisions will not be made on a timely ba sis. We recommend imposing a continual obligation on operators to assess whether the aor itself, the aor and corrective action plan and all other plans required by the regulations should be revised, requiring an annual certification stati ng that the owner or operator has reviewed the circumstances (including operating and monitoring data) during the
p receding year to determine whether these circumstances warranted a revision of the aor and any plans, and requiring that revisions be done when required by the director as well as when the operator de termines that conditions warrant. To accomplish this, it is useful to break down the concept of "reevaluation" into two ideas - "assessment" of the need to revise the aor and all plans and the actual process of "revision." we believe that these suggestions will result in increased accuracy and reliability in th e site performance data while avoiding work that is not warranted by the site data and site performance. Moreover, a continuous obligation to assess whether re visions are needed, when coupled with an annual certification re quirement (see proposed §146.91( d) below) will create a clear accountability trail for both operator and director in case of disputes. Given this annual certificati on process, we believe it is unnecessary to require a reevaluation on a fixed basis every 10 years in every case.

An annual certification requirement can also be used to enhance the ability of both Director and operators to keep track of which plans require updating and whether or not plans that ought to be update d have in fact been revised. Such a shared understanding is essential if th ere is to be the "ongoing dialogue" between regulators and operators that EPA anticipates. We considered the inclusion of an annual report as descri bed in the preamble at 73 Fed. Reg. 43518, but concluded that the benefits of that particular report would be outweighed by the burden. The annual certifi cation we are recommending would be uch simpler. We recommend:

That §146.84(f) be revised to read as follows:

"(f) (1) Notwithstanding the requirement in paragraph (2)(i) of this subsection to perform a reevaluation of the area of review at the frequency set forth in the area of review and corrective action plan, the owner or operator must also conduct the following whenever warranted by material change in the monitoring and operational data or in the evalua tion of the monitoring and operational data by the owner or operator:

"(i) reevaluate the area of review by performing all of the actions specified in paragraphs (c)(1) through (3) of th is section to delineate the area of review and identify all wells th at require corrective action;

"(ii) perform corrective action on well s requiring corrective action in the reevaluated area of review in the same manner specified in paragraph (d) of this section; and

"(iii) submit an amended area of re view and corrective action plan or demonstrate to the Director through moni toring data and modeling results that no change to the area of review and corrective action plan is needed."(2) Except as provided in paragraph (3) of this subsection, the owner or operator shall also conduct a reevalua tion by performing all of the actions specified in subparagraphs (1)(i) through (iii) of this subsection:

"(i) Within the time periods specified in the area of review and corrective action plan for conducting such a reevaluation of the area of review; or

"(ii) If an area of review evaluation or reevaluation has not been performed
p ursuant to §146.84(c) and (d) for the ge ologic sequestration project during the preceding ten (10) years, then within six months after the passage of that 10-year period.

"(3) The Director shall waive the requi rement for a reevaluation pursuant to either §146.84(f)(2)(i) or (ii) if the owner or operator demonstrates to the Director through monitoring a nd operational data and modeling results, such as those reviewed annually pursuant to sect ion 146.95, that such a reevaluation is not warranted by material change."

Response: EPA disagrees with the proposed changes and believes that periodic AoR reevaluation at a set frequency of at least every 5 years is necessa ry to ensure protection of USDWs from endangerment and address the uncertainties inherent in predic tive modeling. Periodic AoR reevaluations at §146.84(e) ensure that a deliberate effort is made to verify, based on monitoring and oper ational data, that the CO2
p lume is moving within the subsurface as predicted. EPA believes that less fr equent reevaluations may not be sufficient to appropriately model plume and pressure front movement, establis h conditions for corrective action, and ensure protect ion of USDWs from endangerment.

EPA agrees that site-specific info rmation will influence the need fo r AoR reevaluations, and clarifies that if site monitoring data agrees with the exis ting AoR delineation, a model recalibration may not be necessary, and the AoR reevaluation may consist of a demonstration that the current AoR delineation is adequate based on site monitoring data.

Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment); 4700 2.7 Proposed Recordkeeping a nd Reporting Requirements (40 CFR 146.91) Comment: In addition, we recommend the following new §146.95:

"146.95 Plan Maintena nce and Update

"(a) Owners or operators must submit an annual statement, signed by an appropriate company official, confirming that the company has:

"(i) reviewed the monitoring and operati onal data that are relevant to a decision on whether to reevaluate the ar ea of review and the monitoring and operational data that are relevant to a decision on whether to update a plan identified in §146.82(p) or (u) through (x) or the quality assurance plan for all testing and monitoring requirements; and

"(ii) determined whether an y updates were warranted b y material chan g e in the Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25317monitoring and operational data or in the evaluation of the monitoring and operational data by the owner or operator.

"(b) Owners or operators must submit either the update d plan or a summary of the modifications for each plan for which an update was determined to be warranted pursuant to subsection (a) of th is section. The Director may require submission of copies of any updated plans and/or additional information regarding whether or not updates of a ny particular plans are warranted.

"(c) The Director may require the revisi on of any required plan whenever the Director determines that such a revisi on is necessary to comply with the requirements of this subchapter."

Response: EPA agrees with the commenter that review of the GS project plans is appropriate. The final rule includes provisions that owners or operators review and update the AoR and corrective action plan, the testing and monitoring plan, and the emergency and remedial response plan throughout the life of the
p roject (these provisions are added at §146.84( c), §146.90(j), and §146.94(d)). Owners or operators must review each plan and identify necessary amendmen ts to the plan or demonstrate to the Director that no amendment is needed. These reviews must be pe rformed within one year of an AoR reevaluation, following any significant changes to the facility (e.g., the addition of monitoring or injection wells), or when required by the Director.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) Comment: With respect to the emer gency and remedial respons e section, we propose two changes - change §146.94(b)(4) to read:

"Implement the emergency and remedial response plan approved by the Director, and keep the Director appriz ed of the implementation."

Response: The final rule retains the language in §146.94( b)(4) as proposed. EPA agrees that the Director should be kept apprised of progress on the implementation of the emergency and remedial response plan but expects that the plan itself will include provisions on communications with the Director. The requirements for an emergency and remedial response plan at §146.94(a) are designed to ensure that owners or operators, as part of their permit application, comprehensively plan what actions would be necessary in the unlikely event of an em ergency. The plan will en sure that operators know what entities and individuals must be notified and what actions must be taken to expeditiously mitigate any emergency situations. The rule sets forth triggers for notification to the Director that initiates consultation on appropriate responses. EPA expects that the owner or operator and Director would discuss the necessary response action and main tain a dialogue and communication throughout the conclusion of any needed actions. EPA is developing guidance on th e development and implementation of emergency and remedial re sponse plans for GS sites.

Other EPA Comment Codes and Descriptions: 5800 2.13 Comments on emer g enc y and remedial Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25318

Commenter Name: John McManus Letter ID: 0294 Commenter Or g anization: American Electric Powe r Comment ID: 25319response (40 CFR 146.94) Comment: and §146.94(d) to read:

"The owner or operator must notify the Di rector and obtain his approval prior to conducting any well workover or other reme diation measures not listed in the emergency and remedial response plan."

It should be noted that the language chosen here for §146.94(d) relates specifically to remediation measures and not to emergency responses, which should not be delayed to seek approval when immediate response action is necessary. Every effort should be taken to ensure that emergency responses are comprehensively addressed in the pla n, including appropriate notification
p rovisions and timeframes, but emergency responses should not be delayed when awaiting approvals could impair the effectiveness of the response.

Response: Since proposal, EPA has modified the final regulatory language at §146.94(d) to clarify what constitutes a workover to address a well failure (whi ch invokes remedial actions ) and what constitutes a maintenance-type workover. For maintenance-type workovers (i.e., those that are scheduled in advance), the owner or operator must notify a nd gain approval from the Director prior to beginning the workover. In the final GS regulation, EPA has moved this re quirement to the reporting requirements at §146.91(d) to clarify its intent.

Regarding concerns that notification could delay responses, EPA clarifies th at the GS rule (at §146.94 (b)) describes procedures owners or operators mu st take in emergency situations. Specifically, upon determining that there is a problem with the well that may endanger a USDW, the owner or operator must first cease injection, then take all steps reas onably necessary to identify and characterize any release, notify the Director, and implement the approved emergency and remedial response plan, which may include a well workover. EPA believes that ceasing injection (which the owner or operator would do immediately and before notifying the Director) is the action necessary to prevent or mitigate endangerment of USDWs, as required under the SDWA.

Comment Code: 1250 1.1.1.4 Flexibility is needed (performance-based standards)



### Individual Comments

Comment: Second, the regulations should be suffic iently flexible to take into consideration site-specific characteristics and performa nce-based measures, and should be sufficiently adaptable to incorporate lessons learned from ongoing
p ilot and demonstration projects.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineatin g the AoR, testin g and monitorin g the site, performin g corrective action, and Commenter Name: Karl R. Moo r Letter ID: 0109 Commenter Or g anization: Southern Company, on behalf of Edison Electric Institute (EEI) Comment ID: 21993p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Regarding the comment that flexibility would allow the incorporation of information gained from pilot, demonstration, and early commercial projects, EPA a dds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regulation, EPA plans, every six years, to collect and review proj ect data on GS research projects to determine whether the appropriate amount and types of information a nd appropriate documentation are bei ng collected, and to determine if modifications to the requirements are appropriate or necessary.

Comment: Our second message for EPA today addr esses the importance of regulatory flexibility.

Regulatory flexibility is essential for ca rbon capture and storage projects. EEI cautions against overly prescr iptive, one-size fits all re gulations because they add costs without ensuring greater protect ion to underground sources of drinking
water.

Because no two geologic formations are the same, no two CCS projects will be the same. The geologic framework in the sel ected injection formation - including, but not limited to, geometry, depth, composition, confining strata, and the number and location of existing wells in th e Area of Review - will all affect how and whether a project moves forwar d. EPA already recognizes that each storage project will be uni que: Under the proposed re gulations, a potential owner or operator of a project will be re quired to present detailed information in its permit application th at is specific to the geologic formation chosen for storage and the surrounding area, both a bove and below the surface. Based on the site-specific information presented, th e UIC program direct or will decide whether to issue a permit.

Consistent with EPA’s approach to permitting, the portions of the proposedregulations that address inherently site-specific issues should allow for sitespecific determinations. Tying regulat ory requirements to site-specific characteristics not only will ensure that properly sited projects are able to secure the approvals and financing needed to move forward, but also will prevent the imposition of unnecessary and expensive requirements that could render some
p roposed projects uneconomic and hinder th e commercial deployment of this critical technology.

Response: EPA agrees that permitting deci sions for GS wells should be ba sed on site-specific factors. The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable fo r GS. Additionally, many of the permit requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testing and monitoring, and injec tion well plugging and post- injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met b y the Commenter Name: Karl R. Moo r Letter ID: 0109 Commenter Or g anization: Southern Company, on behalf of Edison Electric Institute (EEI) Comment ID: 22002owner or operator and areas of Dir ectorial discretion and considerations for how that discretion would be exercised. The Agency believes th is balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each project, while providing consistency in permitting across the U.S.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Comment: EEI and its members also encourage EP A to consider performance-based requirements over prescriptive rules. Again, these are better regulatory options for CCS projects because they ensure that a project is subject to only those requirements that have been shown to be necessary. Moreover, in many cases they will better protect underg round sources of drinking water than default prescriptions.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Other EPA Comment Codes and Descriptions: 2400 1.8 Comments on EPA's adaptive rulemaking
p rocess; 5600 2.11 Comments related to UIC Program primacy for Class VI wells Comment: Flexible, site-specific regulations ask a great deal of the regulator, in this case the UIC program director. Despite these challenges, EEI urges EPA to consider these types of regulations becaus e they present a win-win situation: a higher level of environmental protection while fostering a regulatory regime that encourages investment in CCS proj ects. We also acknow ledge that these benefits cannot be realized unless the UIC program director is given good guidance on how best to exercise his or her discretion. EPA should provide that guidance in either the final regulations or supplemental guidance, in order to ensure that the director’s decisi ons have a sound regulatory basis.

Response: EPA agrees that flexibility is important to accommodate the varied conditions that may be encountered at GS sites. EPA notes that the final rule does allow ow ners or operators flexibility. Many of the permit requirements will be established through site-specifi c plans developed by the owner or operator and approved by the Director, and EPA anticipa tes that owners or operators will consult with the Director as they develop, implement, and update these plans. In addition, the final rule affords the Director flexibilit y to approve alternatives to the requirements in some cases. For example, the Director Commenter Name: Karl R. Moo r Letter ID: 0109 Commenter Or g anization: Southern Company, on behalf of Edison Electric Institute (EEI) Comment ID: 22005

Commenter Name: Karl R. Moo r Letter ID: 0109 Commenter Or g anization: Southern Company, on behalf of Edison Electric Institute (EEI) Comment ID: 22009may in certain situations modify the length of the post-inject ion site care peri od or approve an alternative post-injection site care timeframe as part of the pe rmitting process under §146.93, allow the use of alternate methods for mechanical integrity testing, and waive the requirement that wells be designed to inject below the lowermost USDW. Addi tionally, the regulations provide flexibility for selecting appropriate sites and target formations at §146.82, well construction specifics at §146.86, and testing and monitoring regimes at §146.90, provided the owner or ope rator can demonstrate that the injection and storage will not e ndanger USDWs and that minimum requi rements for the site are met.

EPA agrees with commenters on the importance of allowing Directors discretion given the variety of geologic settings in which GS will be applied. EPA recognizes that St ate, Tribal, and DI UIC Program Directors are in the best position to evaluate th e unique issues related to well depth, geology, and hydrogeology that are posed by a Class VI well. Some degree of flexibility is needed for Class VI wells because each decision made will be site-specific and conditions will differ from state to state. The GS rule balances the need for these site-specific decisions with the ne ed for minimum Federal requirements to ensure national consistency whil e ensuring the protection of USDWs. To ensure the final rule is applied consistently, EPA is deve loping guidance materials and plans to conduct on-line and in-person training for States, Tribes, and Territories that describe the process of applying for and receiving
p rimary enforcement responsibility (primacy) for GS Class VI we lls under Section 1422 of SDWA, as well as the technical and administ rative issues related to devel oping GS regulations that are the equivalent of minimum Federal criteria and requirements. The guidance will be available at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

As part of its adaptive approach, if EPA finds that there is not sufficient consistency in the permits so that USDWs are not being su fficiently protected from endangerment, it will consider changes to the
p ermit requirements in the future.

Comment: 2. Given the direct impact this program will have on the electric utility industry, we appreciate EPA' s goal of establishing certainty and transparency to the requirements for Class VI carbon dioxide injection. It is also crucial, however, for the regulations to reflect the challenge s inherent in crafting controls for commercial CO2 injection a nd storage activities when such largescale commercial operations are only at the nascent stage. The fundamental challenge confronting EPA in this rulema king is to establish a cost-effective and environmentally sound regulatory program to cover a range of operations for which the technology will not be commercial ly deployed for a number of years. To meet this challenge and establish a wo rkable regulatory framework over the coming decades for the long-term storage of carbon dioxide, EPA must craft the regulations with flexibility so that th ey may be fine-tuned as industry and regulators alike gain experience with large-scale carbon dioxide sequestration.

3. Because information and technology rela ted to carbon sequestration are sure to develop as more experi ence is gained, USWAG urges EPA to avoid blanket
p rohibitions or arbitrary absolutes in the Final Rule. We agree that the standard underlying the tec hnical requirements for carb on dioxide sequestration wells is the protection of underground s ources of drinking water. However, because it is difficult to know at this point what future technologies will be developed for injection and long-term storage of carbon dioxide in a manner that is protective of USDWs - and because there is sure to be demand for si g nificant Commenter Name: Paul Pike Letter ID: 0111 Commenter Or g anization: Ameren Corporation on behalf of USWAG Comment ID: 22401capacity for CO2 storage - EPA should not prematurely preclude injection in specific types of sites or through certain methods. The Final Rule should leave the door open for a range of injection sites and methods - some of which are unrecognized, or even unknowable, at this point in time - provided that the ultimate objective of protecting USDWs is achieved.

Response: The Agency agrees that flexibility is important , and believes that th e Class VI requirements balance site-specific flexibility with USDW protection. Rather than setting performance or technologybased standards for GS projects, EPA is adopting a flexible approac h, where operators of GS projects would develop and implemen t site-specific plans for delineating the AoR, testing and monitoring the site, performing corrective action, a nd post-injection site care. EPA believes that the plans—which would be reviewed and approved by the Director and periodically updated throughout the life of the
p roject—promote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a particular project.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating de ployment are outside the scope of the GS rulemaking.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment); 5000 2.8 Proposed Well Plugging and Po st-Injection Site Care Requirements Comment: 6. Because of the widely varied characte ristics and limitations of different carbon dioxide sequestration projects, it is essential to incorporate
p erformance-based standards into the Final Rule, leading to a site-specific approach to requirements for Area of Revi ew reevaluation and post-injection site care and closure periods.

Response: The post-injection site care re quirements in the final GS ru le, as specified in §146.93(b), incorporate a combination of a fixed timeframe a nd a performance standard approach. The GS rule offers owners or operators flexib ility regarding the duration of the PISC timeframe by: (1) allowing theDirector discretion to shorten or lengthen the PISC timeframe during the PISC period based on sitespecific data, pursuant to requirements at §146.93(b); or (2) affording the Director discretion to allow a Class VI well owner or operator to demonstrate, based on substantial da ta during the permitting process, that an alternative PISC timefr ame may be appropriate if it ensures non-endangerment of USDWs
p ursuant to requirements at §146.93(c). EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensurin g USDW protection. Both approaches will utilize site-specific data, Commenter Name: Paul Pike Letter ID: 0111 Commenter Or g anization: Ameren Corporation on behalf of USWAG Comment ID: 22405and be based on pressure mo nitoring and USDW impacts.

EPA is developing guidance to assist owners or opera tors in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 a nd §146.93. Additionally, the gui dance will assist Directors in evaluating proposed we ll plugging plans and post-injection si te care and site closure plans under §146.92 and §146.93. The guidance describes recomm ended approaches for how an owner or operator could plug injection and m onitoring wells; perform post-inject ion monitoring; demonstrate the appropriateness of an alternative pos t-injection site care time frame; demonstrate non endangerment; and
p erform site closure activities. The guidanc e will be available on EPA's web site, at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

In response to comments about AoR evaluation, EPA disagrees that the GS regulation should include
p erformance-based standards for AoR calculation. However, EPA believes that consideration of sitespecific conditions is appropriate for the AoR calcul ation and reevaluation process. EPA believes that the flexibility incorporated into the AoR and corrective action plans and the provision for AoR reevaluation as required at §146.84(e) provide for an ongoing review of the site and a dialogue between the Director and the owner or operator to ensure that the most appropriate modeling and corrective action technologies are used to protect USDWs from endangerment.

Comment: Wells are indeed a fundamental component of a geologi c storage system. Having appropriate design, construction & operati ng requirements for these wells is necessary to ensure delivery of the secure storage of CO2.

Site-specific performance-based guidelines, like the well-relate d examples I’ve noted, will serve the purpose of requiri ng application of the appropriate technological solutions to protect USDWs.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Comment: The Proposal does not include sufficient flexibility. Congress mandated, through Section 1421(b)(3)(A) of the SDWA, that UI C regulations develope d by EPA permit or provide consideration of varying ge ologic, hydrological, or historical conditions in different States and in di fferent areas within a State. Thus, Congress cautioned EPA against a ‘one-siz e-fits-all’ regulat ory scheme, and mandated consideration of local conditions and practices. However, the Proposal does not allow State directors to use th eir expertise and knowledge to account for these varying conditions. Commenter Name: Brian Williams Letter ID: 0116 Commenter Or g anization: BP Alternative Ener gy Comment ID: 22056

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24741EPA states in the preamble that its reason for selecting Alternative #3 is because it ‘provides flexibility whil e creating a framework of minimum requirements to ensure consistency across the nation.’ However, by selecting Alternative #3, EPA selected as a starti ng point the requirements for Class I industrial non-hazardous wells. Because of this, the flexibility is restrained at the very outset.

Using as the reason the unknowns and th e unique characteristics of CO2 geosequestration (buoyancy, corrosivity, high injection volumes, etc.), the Proposal seems to include th e entire slate of possible te chnologies available to complete, operate, monitor and close a UI C well and the injection/confining formations. In a few areas, the Proposal provides the Director with discretion to set certain appli cation, permit, and monitoring crit eria that are appropriate to local geologic settings. However, b ecause EPA began with an unnecessarily stringent Class I framework, and a dded numerous other nondiscretionary requirements, the flexibility is insuffic ient. The result is that the Proposal is unnecessarily prescriptive and costly.

Response: EPA agrees that flexibility is important to accommodate the varied conditions that may be encountered at GS sites while en suring the protection of USDWs.

The technical requirements in Alternative 3 (and the final GS rule) build upon the long-standing UIC regulatory framework for deep wells and are appropriately tailored to address the unique nature of fullscale CO2 GS, including the volumes of CO2 to be injected, the buoya nt and mobile nature of the injectate, and its corrosivity in the presence of water.

The regulation provides flex ibility for selection of appropriate sites and target formations (under §146.82), well construction specifics (under §146.86), and testing and monitoring regimes (under §146.90), provided the owner or operator can demonstr ate that the injection and storage will not endanger USDWs and that minimum requirements for the site are met.

Comment: 3. EPA should provide more flexibilit y in the siting requirements: a. acknowledge that some sites offer very good protection when compared to others and ease regulatory burden on those site s; b. promote transfer of EOR to storage; c. delete the requirement that the confining zone be free of all transmissive faults or fr actures; d. delete references to multiple confining zones; and e. revise the Proposal to allo w for site-specific characteristics and
p erformance- based determinations.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project. Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24745Please see the remainder of EPA’s responses to this comment for further details related to transitioning of ER projects for GS and c onfining zone requirements.

Other EPA Comment Codes and Descriptions: 3824 2.3.1.2 Cementing of long-string casing (seeking comment) Comment: 4. EPA should provide more flexibiilty in construction, for example, delete the requirement that the long string ca sing be cemented to the surface.

Response: EPA believes that the requirements for long-string casing are appropriate and offer appropriate flexibility: §146.86(b)(3) requires that the long-string casing extend to the injection zone and be cemented by circulating cement to the surface in one or more st ages. It does not, however, specify how cementing would be accomplished, and gives fl exibility to the owner or operator to propose alternate methods to provide a sufficient amount of cement to meet the standard that USDWs are
p rotected from endangermen t, subject to the approval of the Director.

EPA notes that there are many potential ways to m eet the requirement, such as the use of staged cementing. See the discussion of Class VI well cons truction requirements in the preamble to the final GS rule for additional informat ion. Additionally, EPA is developi ng guidance on the construction of Class VI wells. This guidance will be available on EP A’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

EPA adds that other aspects of the rule allow flexibility based on site-s pecific considerations: with their
p ermit applications, owners or operators must submit proposed well construction procedures, as specified at §146.82(a)(12), that address the specific dr illing and injection environment and the chemical and physical nature of the CO2 inj ected stream. The Director must ev aluate the appropriateness of the
p roposed construction based on site-s pecific information about the inj ection project, including injection
p ressures, injection and confining zone lithology, and information about the carbon dioxide stream, as
p rovided in the final GS rule at §146.86(b)(1).

Other EPA Comment Codes and Descriptions: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) Comment: 5. EPA should provide more flexibiilty in operation. For example, allow an EOR operator to demonstrate that CO2 is se questered, and instead of a 10-year default period for reevaluation of the area of review, allow the timing for suchreevaluation to be determined based on site-specific characteristics and sitespecific monitoring of the CO 2 plume and pressure front.

Response: EPA disagrees that the GS re gulation should include performa nce-based standards for AoR calculation. However, EPA believes th at consideration of site-specific conditions is appropriate for the AoR calculation and reevaluation process. EPA believes that the flexibility incorporated into the AoR and corrective action plans and the provision for AoR reevaluation as required at §146.84(e) provide for an ongoing review of the site and a dialogue between the Director and the owner or operator to ensure that the most appropriate modeli ng and corrective action te chnologies are used to protect USDWs from endangerment. Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24746

Commenter Name: Leslie Sava g e Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24748However, EPA believes that setting a minimum reevaluation frequency is appropriate. In the final rule, the Agency changed the minimum frequency for the AoR reevaluation at §146.84(e) from 10 years to at least every 5 years in the final GS rule. EPA believes that this revised frequency addresses commenters' concerns about the inherent uncertainties in modeling CO2 movement, the emerging nature of GS technology, risk-based targeting of monitoring activiti es, and the unique nature of CO2 GS.

Comment: General Comments Effort should be made, to the extent practicable, to keep provisions for Underground Injection Control (UIC) of CO2 consistent with already known and understood UIC principles and regulations . Care should be taken to avoid overestimating the risks associated with GS, in order to ensure that the final rules are not excessively burdensome or complex. Of course, the rules must simultaneously ensure adequate protection of human health and the environment. However, excessive, complex regulatory requi rements have the potential to limit development of a technology that will be critical to our ef forts to addr ess climate change effectively, adding si gnificantly to costs for a program that will already result in significant additi onal costs to the energy sector , industry and consumers.

Response: EPA disagrees that the requirements in the GS rule overstate the risk associated with GS. The UIC Program, under the authority of the SD WA, provides a strong framework for regulating injection of CO2 for GS; the GS regulation tailors the UIC requir ements to address the unique issues associated with large-scale GS including large in jection volumes, the rela tive buoyancy of CO2, its corrosivity in the presence of water, the potenti al presence of impurities in captured CO2, and its mobility within subsurf ace geologic formations.

EPA recognizes the importance of providing clear, fl exible, scalable, and appropriate regulations. EPA b elieves that the GS regulation will provide certainty to industry and the public by providing consistency in requirements across the U.S. and transparency about what requirement s apply to owners or operators.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Other EPA Comment Codes and Descriptions: 1600 1.3 Risk Associated with CO2 GS Comment: 1.) The SWP would like to recommend a risk-based approach to the siting requirements, Area of Review (AoR), monitoring requirements, site-closure requirements, and the grandfather clause. Th e EPA notes in several places within the proposed rule that each GS site is unique with respect to physical and chemical properties. As such, the SW P recommends that the EPA adopt a risk/performance-based approach for each site. Reasoning for th is recommendation as it relates to specific aspects of th e proposed rule are outlined by relevant sections:

Response: EPA has taken a re g ulator y approach that promotes US DW protection, incorporates Commenter Name: Carl Carlsson Letter ID: 0131 Commenter Or g anization: SUEZ Energy Generation NA, LLC Comment ID: 21525

Commenter Name: Dawn A. Thorne Letter ID: 0134 Commenter Or g anization: University of Utah Energy and Geoscience Institute on b ehalf of the Southwest Regional Partnership Comment ID: 21653flexibility or permitting authority discretion when appropriate, s eeks to limit burden on owners or operators and permitting agencies, and provides a f oundation for national consis tency in permitting ofGS projects. Under the final rule, many of the permit requirements must be established through sitespecific plans (e.g., AoR and corrective action plan, testing and monitoring pla n, etc.) developed by the owner or operator and approved by the Director. Consequently EPA e xpects that owners or operators will consult with the Director as they develop, implement, and update these plans. Additionally, the Director has the discretion to approve alternatives to the requirements in some cases. For example, the Director may in certain situations modify the length of the post-injection site care period or approve an alternative post-injection site care timeframe as part of the pe rmitting process under §146.93, allow the use of alternate methods for mechanical inte grity testing (if approve d by EPA) under §146.89, and waive the requirement that wells be designed to inject below the lowermost USDW under §146.95.

Comment: In conclusion, the SWP recommends a si te-specific, performance/risk-based approach to the fmal regulatory fram ework. This method will allow for consideration of the uniquene ss of each CCS site, and ac commodate advancements in technology over time. The SWP would al so urge collaboration with other regulatory agencies and private insure rs to establish a sound regulatory framework with long-term funding and oversi ght at the state level. Thank you for the opportunity to comment.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Comment: Tailored Regulatory Requirements

WDNR supports EPA's selecti on of a flexible regulatory approach which recognizes that full-scale projects involving long-term storage of CO2 are unique due to the volume of CO2 that is to be inje cted, the buoyancy and viscosity of the
p roposed injectate, the corrosive nature of CO2 when mixed with water, and the many geologic formations that can potentially be used for CO2 storage. By building on the existing regulatory framework for other deep injection wells and
p roviding flexibility and/or discretion to the permitting authority to address site specific variability, the require ments being proposed by the Agency appropriately balance the need to provi de protection to the nation's underground sources of drinking water with the need to provide a degree of regulatory certainty and consistency to owners and operators of GS facilities,

Response: EPA acknowled g es the comment, and a g rees that permittin g decisions for GS wells should Commenter Name: Dawn A. Thorne Letter ID: 0134 Commenter Or g anization: University of Utah Energy and Geoscience Institute on b ehalf of the Southwest Re g ional Partnership Comment ID: 21665

Commenter Name: Jill D. Jonas Letter ID: 0135 Commenter Or g anization: Wisconsin Dept. of Natural Resources (WDNR) Comment ID: 21669b e based on site-specific factors. Th e GS rule requires owners or opera tors to submit, and Directors to consider, extensive site-specific da ta, specified at §146.82, to demonstrate that a site is suitable for GS. Additionally, many of the permit re quirements for GS wells are establ ished through individualized sitespecific plans for AoR and corr ective action, testing and monitoring, and injection well plugging and
p ost-injection site care and site clos ure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Directorial discretion a nd considerations for how that discretion would be exercised. The Agency beli eves this balance allows for GS projects to be designed and permitted to address the unique, site-s pecific aspects of each project, while providing consistency in permitting across the U.S.

Comment: 2. EPA should adopt a performance-based regulatory scheme rather than the "Tailored-General Provision" approach it has proposed. Any regulatory approach to geologic sequestration must be based on the recognition that no two sites are alike. Because this is so, it is crucia l that the regulatory scheme that is ultimately implemented be one that is flexible and performance-based, rather than one that imposes acro ss-the-board requirements that may be appropriate for one kind of site but inappropriate for anot her. The need for flexibility is only increased by the fact that there is stil l a good deal to learn about large-scale geologic sequestration. Premat ure imposition of prescrip tive requirements could damper the development and future interest in these projects by companies that might otherwise be interested in en tering this new field. EPA should use
p erformance-based standards and should maintain flexibility in the creation and implementation of regulatory requirements, in light of the variations in geologic formations that will be encountered from project to project. Imposition of "one-size-fits-all" requirements would be inappropriate and would unnecessarily hinder full development of geologic sequestration technology.

TPA believes that the best approach would be for states with primacy to develop specific, performance-based standards based on the particular geologic characteristics and experience with deep well injection activities present in the respective states. Texas, in part icular, has a breadth and depth of experience in this area and our Texa s regulatory body, the Texas Railroad Commission, has the technical expertise and knowledge to develop criteria suited to our state. Geologic seque stration can be an important tool in the nation's effort to reduce greenhouse gas emissions, but only if its implementation is not hindered by unnecessarily burdensome or in flexible regulations. TPA recognizes that performance-based sta ndards impose an increased burden on regulators, but if geologic sequestration is to be widely utilized as a means to reduce carbon dioxide emissions, then there really is no alternative.

The importance of protecting drinking wa ter is obvious, and no one in the oil and gas industry is seeking to cut regulat ory corners. TPA is simply urging EPA to recognize both the need for flexibility in the re gulatory regime and the importance of fostering public confiden ce in the safety of geologic sequestration technology.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than settin g performance or technolo gy

- b ased standards for GS pro j ects, EPA Commenter Name: Patrick Nu g ent Letter ID: 0143 Commenter Or g anization: Texas Pipeline Association (TPA) Comment ID: 23124is adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

In response to the comment that States with primacy be able to develop “performance-based standards,” the Agency clarifies that States, Tribes, and Terr itories can develop require ments for Class VI and submit primacy applications (under Section 1422 of the SDWA) for review and approval by EPA as long as the requirements are as stringent as or more stringent th an the Federal minimum requirements.

Other EPA Comment Codes and Descriptions: 2400 1.8 Comments on EPA's adaptive rulemaking
p rocess Comment: General Comment

1. TVA acknowledges the challenge of deve loping a rule to provide regulatory certainty for the GS of CO2 in order to fo ster industry adopti on of carbon capture and storage (CCS) in the face of consid erable technological and experiential uncertainty about safely injecting a nd sequestering the huge volumes of supercritical CO that would be required to meet the goals of future climate change legislation. In the face of such uncertainty, th is rule is justifiably stringent for protecting USDWs, ecologi cal resources, and the public. Because scale-up from experimental to fully operational wells will provide the experience necessary to have a rulemaking with the most appropriate protections, TVA requests that a provision be added to require periodic review (possibly every two years initially until sufficient operational experience is gained) and to revise the rule’s flexibility appropria tely where justified. TVA agrees with EPA that the regulatory standard for pe rmitting CO2 GS wells should be the
p rotection of USDWs, which must take precedence over the need to sequester CO2 underground at any site. For this reas on, TVA supports a stringent rule initially as long as a provision is made to revise the rule to incorporate operational experience as it is gained.

Response: EPA agrees that an adaptive approach to th e UIC GS rulemaking is appropriate. The Agency
p lans to use such an approach to ensure that US DWs are protected from endangerment while making it
p ossible to meet the potentially fa st pace of GS deployment. EPA belie ves that an adaptive approach will allow regulatory development to proceed in time to meet the curr ent and future demand for Class VI
p ermits while recognizing the n eed to: continue to gather data from pilot projects and other research as it becomes available; and to enhan ce understanding of the technical and administrative aspects of GS deployment, operation, and technology de velopments. EPA plans, every six years, to collect and review data on GS projects to determine whether the a ppropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

However, the Agency cannot definiti vely predict that future requirements will be less stringent than those in the final GS rule. The A g enc y believes that the Class VI requirements appropriatel y address the Commenter Name: Richard Dri gg ans Letter ID: 0145 Commenter Or g anization: Tennessee Valle y Authorit y Comment ID: 23147unique challenges posed by large-scale GS–including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurities in captured CO2, and its mobility within subsurface formations. Any changes implemen ted under the adaptive rulemaking would be based on technical information and data ge nerated and collected duri ng early GS projects or other research.

EPA believes that reevaluating the GS requirements every si x years is appropriate to allow sufficient time for projects to be permitted, for State and Tribal programs to ap ply for and receive primacy, and for sufficient project data to be coll ected. For example, once the first GS projects are permitted, injection commences, and monitoring data are generated and an alyzed, EPA can begin to review this data to verify the applicability and appropriateness of the requirements including the usefulness of AoR calculation models, and the utility and design of monitoring plan s and corrective action plans. As construction and operation of GS projects continue (e.g., as AoR reevaluations are conducted or when the first projects cease inject ing), EPA will have additional opportunities to eval uate the requirements in the course of subsequent reviews.

EPA believes that shorter review intervals, e.g., 2 years, as the commenter suggests, would not provide sufficient time for projects to be permitted, State and Tribal programs to appl y for and receive primacy, and sufficient data to be collected. EPA clarifies that, if early project data indicate before six years that revisions are appropriate, EPA will publish new requirements prior to then.

Comment: 1. Regulatory ("Director’s") Discretion - TVA supports a flexible rule that vests in the Director the discretion to grant certain approvals. However, where the Director is provided such disc retion (e.g., for imposing secondary containment, requesting additional testing, monitoring CO2 fluxes in surface air and soil gas, changing the 50-year default post injection care requirement, shortening the notification period for pl ugging an injection well or approving site closure plans), the proposed rule s hould include factors that the Director must consider in exercising discretion.

Response: The final GS rule includes a balance of specifi c criteria to be met by the owner or operator and areas of Directorial discretion and considerations for how th at discretion would be exercised. The Agency believes this balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each pr oject, while providing consistency in permitting across the U.S.

EPA is developing guidances for States that descri be the process of applyi ng for and receiving primary enforcement authority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum federal criteria and requirements. The guidance will describe area s of Directorial discretion and considerations for how that discretion would be exercised. This guidance wi ll be available on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm.

Comment: SUMMARY Commenter Name: Richard Dri gg ans Letter ID: 0145 Commenter Or g anization: Tennessee Valley Authority Comment ID: 23148

Commenter Name: Kenneth Alexande r Letter ID: 0146 Commenter Or g anization: Old Dominion Electric Cooperative (ODEC) Comment ID: 21709ODEC applauds the efforts EPA has taken thus far to instill "certainty" and "transparency" into the fu ture Class VI C02 regulator y regime, 73 Fed. Reg. at 43496. The challenge EPA faces is to cr aft a Final Rule for commercial CO2injection appropriate for activities that will larg ely be conducted in the future. EPA has had to confront many t echnical uncertainties regarding the establishment and operation of GS wells. Because many of the technical aspects are unknown, it is also very difficul t to develop a clear understanding ofproject risks and liabilities. As long as risks and liabilities are largely unknown and open-ended, private companies will not step fo rward to offer insurance and other risk management pr oducts, and it will not be possible to obtain the level of financing needed to undertake a costly GS operation. We hope the pilot carbon capture and sequestration (CCS) projects conducted by DOE and other entities will help resolve some of these uncertainties. EPA needs to establish clear, reasonable regulations that are envir onmentally protective and cover a range of operations for which th e technology will not be commercially deployed for a number of years. To th e extent practicable, EPA needs to establish a single, clear, reasonable and protective liability regime for an activity where the nature of the risks ar e different from many other industrial activities and the full extent of possibl e risks from full scale CCS operations are presently unknown. Comments Regarding UIC Regulations

1.Because ofthe difficulty of regulating future activities, we urge EPA to continue to use a "performance based" a pproach in developing the requirements for Class VI UIC wells. This way, rules can be readily adjusted and fine-tuned as industry and regulators alike gain experience with large-scale CO2 sequestration.

2.Because information and technology related to carbon sequestration will evolve as industry and regulators gain experience with CCS, ODEC urges EPA to resist
p lacing blanket prohibitions or detailed ope rational specifications in the Final Rule.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCSp rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Comment: The real challenge, however, will be fo r EPA to create a regulatory framework flexible enough to allow for technologies th at may not be commercially available for many years. That is, EPA must cr aft its CCS regulations with enough flexibility so that they ma y be modified to include technologies not yet on the market.

Response: EPA is using an adaptive approach to re gulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Other EPA Comment Codes and Descriptions: 1680 1.3.8 Don't overstate risk, don't stigmatize CO2 Comment: a. Distorts Public Perception

By making the proposed rule so strict, the public may unduly perceive CCS as a dangerous activity. Consider that th e proposed rule requires a secondary containment field for CO2 storage. Such a requirement is unprecedented both domestically, in the UIC program (including for storage of hazardous wastes in Class I wells), as we ll as internationally. [FN10 Countries such as Norway, Canada, and Australia, which have carbon capture and storage projects currently underway, do not require secondary cont ainment zones, and in fact, those countries regulate CCS using existing petroleum laws.] Singling out carbon capture and storage for this heighten ed and substantially more rigorous requirement would suggest to the public that EPA thinks geologic storage of carbon dioxide is more dangerous than the underground injection of other substances. Since EPA is the agency charge d with protecting the environment, the
p ublic could be easily swayed by EPA’s apparent apprehension of carbon capture and storage as currently embodied in the proposed regulations. In order to create a regulatory scheme that fosters carbon capture and storage development and deployment, EPA should reconsider how it has characteri zed carbon dioxide injection -- both explicitly and implicitly -- in its final regulations.

Response: EPA disagrees that the GS regulation overstate s the risk of CO2 injection. EPA recognizes that injecting large volumes of CO 2 for GS poses unique challenges th at, if not properl y managed, could endanger drinking water sources and have other adverse impacts. However, with proper site selection, the final, tailored, Class VI re quirements address the large volumes of CO2 injected, its buoyancy,
p otential corrosivity in the presence of water, and potential impurities in the CO2 stream. In addition, EPA expects the tailored permitti ng, siting, construction, operation, mo nitoring, and post- injection site care requirements in the GS rule to prevent leakage from injection formati ons and protect USDWs.

EPA also disagrees that the tailored requirements wi ll create a negative publ ic perception of GS. The A g enc y believes that a demonstrati on to the public that GS pro j ects are meetin g the GS rule's tailored Commenter Name: William Kovacs Letter ID: 0148 Commenter Or g anization: U.S. Chamber of Commerce Comment ID: 21770

Commenter Name: William Kovacs Letter ID: 0148 Commenter Or g anization: U.S. Chamber of Commerce Comment ID: 21773requirements will likely improve confidence in the project and help address public questions and

concerns.

Regarding secondary containment, EPA retain s the requirement to identify additional containment/confining zones, if required by the Director, as proposed, at §146.83(b). EPA acknowledges that such additional z ones may not be needed in all circumstances, and clarifies that this requirement is at the Director's discretion, based on his or her understanding of a particular site. EPA believes that, in some situations, the presence of additional confining and c ontainment zones above the
p rimary (i.e., lowermost) confining zone can improve USDW pr otection. These laye rs could further impede vertical fluid movement a nd allow for pressure dissipation, and also provide additional sites for monitoring, mitigation, and remediation. The Agency's decision is supported by commenters representing states, water associations, and an electri c utility who assert that these requirements promote a flexible, risk-based, site-specific approach to char acterizing and permitting a si te for GS projects, and are intended to improve understanding of the project as a whole and promote bett er modeling of the site. While other countries may not require such add itional protection, EPA beli eves that providing the Director this additional di scretion is an important element of as suring that GS activities will not endanger USDWs.

Comment: Conclusion

CCS is not a "silver bullet" but an innovative solution for reducing CO2 emissions to the atmosphere. The Chamber applauds EPA for seeking out novel and important approaches for addressing clim ate change, reducing CO2 emissions, and continuing to protect our vi tal sources of safe drinki ng water. Nevertheless, the Chamber encourages EPA to address the potentially serious im pediments to CCS development and deployment that have been raised in these comments.

Response: EPA acknowledges the comment. Please see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: The proposed Class VI rule addresses all of the important issues which must be addressed in order to pr otect USDWs when geologic sequestration of CO2 is undertaken. Actions required by the rule ar e generally conservative, which is good, but, in three areas, discussed be low, requirements are overly, and unnecessarily, conservative.

Response: EPA acknowledges the comment. Th e requirements for GS projects are tailored to address the unique issues associated with GS, including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the poten tial presence of impuritie s in captured CO2, and its mobility within subsurf ace geologic formations.

Please see the remainder of EPA' s responses to this comment for further details. For additional information on EPA's final re g ulator y approach, please see the final ru le and preamble as well as the Commenter Name: William Kovacs Letter ID: 0148 Commenter Or g anization: U.S. Chamber of Commerce Comment ID: 21777

Commenter Name: Larr y M y e r Letter ID: 0149 Commenter Or g anization: Lawrence Berkeley National Laboratory (Berkeley Lab) U.S. Department of Energy (DOE) Comment ID: 21796rulemaking docket.

Other EPA Comment Codes and Descriptions: 1420 1.2.1.1 Support the GS rulemaking Comment: Spectra believes the GS Rule should be designed to encourage carbon capture and sequestration as an integral part of any national climate change policy. Second, while Spectra appreciates many of the unknowns that currently exist with respect to commercial scale GS opera tions, sour CO2 [1] from natural gas operations has been safely injected for nearly two decades and such operations present significant opportunities for further reductions in at mospheric CO2 emission through longterm geologic sequestration. Lastly, Sp ectra and many others within the industry have ongoing operations in North America and elsewhere, and we are concerned that, should EPA impose excessive or unreasonable requirements as part of the GS Rule, this could have negative implications for GS activities in other j urisdictions such as Canada - where the majority of Spectra’ s current geologic sequestration activities occur.

1 The term sour CO2 (a/k/a "acid gas" ) is used to describe the by-product generated from natural gas processing and is primarily a mixture of CO2 and H2S but may also contain a smal l amount of impurities.

Response: EPA clarifies that the intent of the GS rule is not to encourage GS or CCS in the US or elsewhere; rather, the purpose of the GS rule is to en sure that, where GS is deployed, it is conducted in a manner that protects USDWs from endangerment. The Agency's authority as it relates to GS is limited to protection of USDWs wi thin the United States.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Minerals Management Service; and the Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research, and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

EPA is using an adaptive approach to regulating GS under the UIC Program. Ev en after finalization of the GS regulation, the Agency plans to collect a nd review data every six years on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirement s are appropriate or necessary.

Comment: II. FOR CCS TO BE VIABLE, GS REQUIR EMENTS MUST BE FLEXIBLE, TAILORED Commenter Name: Brianne Metz g e r Letter ID: 0151 Commenter Or g anization: Spectra Energy Corp Comment ID: 21816

Commenter Name: Brianne Metz g e r Letter ID: 0151 Commenter Or g anization: Spectra Energy Corp Comment ID: 21817TO SITE SPECIFIC NEEDS, AND MUST RELY UPON STATE EXPERIENCE.

Under the Proposed Rule, EPA has adopted an approach specifically tailored to the unique characteristics of CO2 deepwell injecti on. While we generally support the Agency’s decision not to be ove rly prescriptive in the development of the GS requirements, certain portions of the technical requirements appear to be excessive and unreasonable and wi ll result in highe r operational costs without meaningful benefits . In the promulgation of the Final Rule, we would encourage EPA to continue to build upon the concept of flexibility, reduce the amount of unnecessary and costly requireme nts, and, in certai n cases, provide greater discretion to the States in deciding the technical specifications applicable to siting, well construction, and monitoring.

Response: EPA agrees that permitting deci sions for GS wells should be ba sed on site-specific factors. The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable fo r GS. Additionally, many of the permit requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testing and monitoring, and injec tion well plugging and post- injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Dir ectorial discretion and considerations for how that discretion would be exercised. The Agency believes th is balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each project, while providing consistency in permitting across the U.S.

EPA disagrees that the Class VI requirements are overly stringent; instead, the GS requirements are tailored to the unique nature of GS, including th e large volumes of CO2 injected, its buoyancy and
p otential corrosivity in the presence of water, a nd impurities in the CO2 stream. EPA believes these tailored requirements are more a ppropriate than Class I or Class II requirements. Please see the remainder of EPA's responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 5000 2.8 Proposed Well Plugging and Post-Injection Site Care Requirements; 5400 2.9 Proposed Financia l Responsibility and Long- Term Care Requirements

Comment: IV. EPA MUST DEVELOP A FLEXIBLE FRAMEWORK TO ADDRESS POSTINJECTION SITE CARE, FINANCIAL ASSURANCE, AN D LONG TERM LIABILITY THAT ELIMINATES OBSTACLES TO COMMERCIAL-SCALE DEPLOYMENT OF CCS.

N umerous studies and commentators have recognized that the principle obstacle to commercial-scale deployment of CC S is regulatory uncertainty over the capture, transport, injection, and storag e of CO2. As stated by a recent GAO report:

The IPCC, two federal advisory committ ee reports, and many stakeholders we contacted a g reed that ke y re g ulator y and le g al issues will need to be addressed Commenter Name: Brianne Metzge r Letter ID: 0151 Commenter Or g anization: Spectra Ener gy Corp Comment ID: 21877if CCS is to be deployed at commerci al scale. Among these issues are (1) confusion over the rules for injecting large volumes of CO2, (2) long-term liability issues concerning CO2 storage and potential leakage, (3) how property ownership patterns may affect CO2 storage, and (4) how the Clean Air Act will apply to facilities that capture CO2. - EPA’s 2007 UIC workshop, attended by more than 200 stakeholders, revealed liability associated with unintended migration of injected CO2 to be a cr itical concern. Simi larly, 19 of the 20 stakeholders we interviewed told us that liability related to CO2 storage was a large or very large barrier to deployment of CCS at a commercial scale, with some noting that liability concerns have already negatively impacted companies’ ability to initiate CCS projects. For ex ample, two stakeholders reported that these concerns had already made it di fficult to obtain insurance for CCS
p rojects. They noted specifically that insurers have difficulty writing insurance policies because of uncertainties associated with and limited data available for CCS, while another added th at investors will not support projects like CCS if they expose them to unlimit ed and undefined long-term liabilities, especially when future revenue streams are uncertain.[14]

The promise of CCS as a strategy to addr ess climate change a nd promote national energy security hinges on resolving this regulatory uncertainty in a way that does not place an unreasonable burden on site owners and operators that would effectively prevent the development of commercial-scale CCS projects in the United States. The EPA has the authorit y under SDWA and the UIC Program to create a flexible framework to address issu es such as post-injection site care, financial assurance, and long-term liab ility in a manner that places enough responsibility on owners and operators to ensure that all applicable best
p ractices are followed, but not so much that it becomes virtually impossible to secure the requisite financing and insura nce needed for CCS projects to be commercially viable.

The potentially unique challenge of resolving the regulatory uncertainty currently inhibiting the development of CC S projects, if done with inadequate attention to existing market dynamics a nd economic realities, likely will
p reclude any commercial-scale deployment of CCS and undermine its effectiveness as a strategy to reduce greenhouse gas emissions. Addressi ng the regulatory uncertainty surrounding post-injection site care, financial assurance, and long-term liability effectively boils down to four overarching questions confronting entities involved in the capt ure, transport, injection, and storage of CO2: (1) length of the post-injection si te care time period; (2) aspects of
p ost-injection site care for which en tities will be responsible; (3) availability and suitability of differ ent risk management instruments for meeting financial assurance requirements; and (4) permanent transfer of all liability to the State. Spectra’s comments on post-injection site care, financial assurance, and long-term liab ility focus broadly on these issues.

14 GAO Report, Climate Cha nge, Federal Actions Will Greatly Affect the Viability of Carbon Capture and Storage As a Key Mitigation Option, Report to the Chairman on the Select Committee on Energy Independence and Global Warming, House of Representatives, GAO-08- 1080, September 2008, at 23, 25. See also Capturing King Coal: Deploying Carbon Captur e and Storage Systems in the US at Scale, WORLD RESOURCES INSTITUTE (2008) at 24 ("In the event of an accident ordamage years after the well is clos ed, who is financially and legally responsible? Current law and policy is unclear on this matter, and more generally on the matter of responsib ility for long-term measuring and monitoring of the site. In particular, the degree to which private parties remain responsible, or the government a ssumes a measure of responsibility, is important.").

Response: EPA acknowledges the commenter¿s request for certainty regardi ng post-injection site care (PISC) requirements for GS wells. However, EPA believes that a certain amount of flexibility is appropriate for setting the PISC ti meframe, given the variety of circ umstances that may occur at GS sites. The PISC requirements in the final GS rule , as specified in §146.93(b), incorporate a combination of a fixed timeframe and a performa nce standard approach. The GS ru le offers owners or operators flexibility regarding the duration of the PISC timeframe by: (1) al lowing the Director discretion to shorten or lengthen the PISC time frame during the post-injection pe riod based on site-specific data,
p ursuant to requirements at §146.93(b); or (2) affording the Director discretion to allow a Class VI well owner or operator to demonstrate, during the permitting process based on substantial data, that an alternative PISC timefram e may be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters¿ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure monitoring and USDW impacts.

EPA recognizes that there are chal lenges associated with financial responsibility for GS projects. However, the Agency believes that in order to protect USDWs from endangerment under the SDWA operators must demonstrate under §146.85 that financia l resources are available to plug the injection well and provide PISC when injection begins.

Under the final GS rule owners or operators may choose from a variety of financial instruments to demonstrate that they meet the financial responsibility requirements under §146.85, provided the Director determines that the dem onstration is adequate to pay for each activity for which financial responsibility is required. EPA is developing guidance (available on EPA¿s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm) to help owners or operators,
p ermitting authorities, and third parties choose and evaluate appropria te financial methods.

Under SDWA authority, owners or op erators of injection wells must ensure protection of USDWs from endangerment and are subject to liability for enfor cement under the Act. The final rule requires an owner or operator to conduct monito ring as specified in the Direct or-approved PISC and site closure
p lan following the cessation of inject ion until he or she can demonstrat e that the GS project no longer
p oses an endangerment to USDWs.

Once an owner or operator has met all requirements unde r Part 146 for Class VI wells and the Director has approved site closure pursuant to §146.93, the owner or operator will genera lly no longer be subject to enforcement for regulatory nonc ompliance. Furthermore, the fi nancial instrument required under §146.85 will be released if it was not used. However, even if site closure is approved, an owner or operator may be held liable for regulatory noncomp liance (e.g., violation of 40 CFR 144.12) in certain circumstances. For example, an owne r or operator may be held liable for noncompliance even after siteclosure if the Director relied on erroneous information (e.g., erroneous modeling data) provided by the owner or operator when approving site closure.

Additionally, an owner or operator may always be subject to any action, su ch as administrative orders or civil actions, the Administrator deems necessary under §1431 of the SDWA after site closure if there is unanticipated migration towards or into a USDW th at causes or threatens imminent and substantial endangerment to public health. If the owner or operator fa ils to comply with the order, he or she may be subject to a civil penalty for each day such viol ation occurs or failure to comply continues.

The Agency clarifies that Class VI well permits may be transferred to another owner or operator
p ursuant to §144.38 whereby all potential liabilities associated with m eeting the requirements of that
p ermit are transferred to th at new owner or operator.

Furthermore, after site closure an owner or operator may remain liable under tort and other remedies, or under other federal statutes incl uding, but not limited t o, the Clean Air Act, 42 U.S.C. §§ 7401-7671; CERCLA, 42 U.S.C. § 9601-9675; and RCRA, 42 U.S. C. § 6901-6992. EPA does not have authority to transfer SDWA or other legal liabil ity for Class VI wells to the Stat e or federal government or a thirdp arty fund. See the final rule preamble for further discussion of EPA's final approach.

Other EPA Comment Codes and Descriptions: 1530 1.2.3.1 State regulatory e fforts on GS (seeking comment) Comment: given the potential size, scope and impact of the sequestration operations. Our main concerns focus on states being gi ven sufficient flexibility to regulate such a program efficiently and effectively.

Response: EPA clarifies that SDWA, under section 1422(b)(3 )(9)(A), requires that the regulations of the Administrator "permit or provide for varying geologic, hydrological, or historical conditions in different states and in diff erent areas within a state." In the fina l GS rule, EPA has provided the Director discretion in applying the GS requirements, taking into account varying conditions, particularly with regard to the evaluation of site characteristics.

For additional information, please see the discu ssion of EPA’s Final Regulatory Approach in the
p reamble to the final GS rule and the section enti tled, “How Does This Ac tion Affect UIC Program Implementation?"

Comment: 1. South Dakota recommends that more fl exibility be given to the type and location of formations where CO2 can be sequestered. At this point EPA is

Response: EPA agrees that permitting deci sions for GS wells should be ba sed on site-specific factors. The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable fo r GS. Additionally, many of the permit requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testin g and monitorin g , and in j ection well plu gg in g and post-in j ection site care and Commenter Name: Steven Pirne r Letter ID: 0153 Commenter Or g anization: South Dakota Department of Environment and Natural Resources Comment ID: 22134

Commenter Name: Steven Pirne r Letter ID: 0153 Commenter Or g anization: South Dakota Department of Environment and Natural Resources Comment ID: 22135site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Dir ectorial discretion and considerations for how that discretion would be exercised. The Agency believes th is balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each project, while providing consistency in permitting across the U.S.

Other EPA Comment Codes and Descriptions: 1410 1.2.1 Comments in support of EPA/rulemaking Comment: EPA is commended for taking this action that begins the process of providing regulatory clarity to a complex and importa nt topic. In its decision process, EPA needs to consider the importance of CCS to the success of the nation's overall climate change, energy independenc e and economic growth strategies. Any rule for geologic storage of CO2 needs to provide an unambiguous framework that
p romotes the development and deployment of CCS while protecting the environment. Also, given the current state of expe rience in geologic sequestration, any
p rescription needs to be flexible and adaptive.

Response: While EPA agrees with commenters that a st able, predictable, nationally consistent, and workable regulatory framework is important, EPA stresses that the focus of the GS rule is to ensure that, where GS is deployed, it is conducted in a ma nner that protects USDW s from endangerment.

EPA agrees that an adaptive and flexible ap proach is appropriate. To protect USDWs from endangerment and meet the potentially fast pace of GS deployment, EPA is using an adaptive approach to regulating CO2 inje ction for GS. The Agency plans to collect and review data every six years on GS
p rojects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary. An adaptive approach will allow regul atory development to procee d in time to meet the current and future demands for Class VI permits while EPA continues to gather data from pilot projects and other research as it becomes available.

Comment: this technology is still years down the roa d. At this point, we ask EPA to lay out a performance based regulatory framework that can be readily adapted to new information and technology gained from th ese yet to be started large scale demonstrations. Also, the requirements should not be so restrictive and costly to make carbon sequestration not a viable option for implementation.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technolo g ical developments related to Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technologies Council (GTC) Comment ID: 23754

Commenter Name: Skiles Bo yd Letter ID: 0160 Commenter Or g anization: DTE Ener gy Comment ID: 21270GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: Comments Regarding UIC Regulations

1. Because of the difficulty of regulati ng future activities, we urge EPA to continue to use a "performance based" a pproach in developing the requirements for Class VI UIC wells. This way, rules can be readily adjusted and fine-tuned as industry and regulators alike gain experience with large-scale CO2 sequestration.

2. Because information and technology re lated to carbon sequestration will evolve as industry and regulators gain experience with CCS, Sa n Miguel urges EPA to resist placing bla nket prohibitions or detailed operational specifications in the Final Rule.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: First, EPA's regulations must reflect a ba lanced approach between the need to
p rotect underground drinking water supplies and the need to avoid regulations that ultimately discourage CCS. While the proposed rule attempts to provide flexibility in the form of director di scretion, in several areas the proposed rule establishes default provisions that w ould apply to all GS sites. EPA must be careful to recognize that each storage site will present unique characteristics. Rather than imposing default provisions on all sites, EPA should utilize performance-based sta ndards in the regulatory program.

Response: EPA a g rees that permittin g decisions for GS wells should be based on site-specific factors. Commenter Name: Joseph Eutizi Letter ID: 0161 Commenter Or g anization: San Miguel Electric Cooperative, Inc Comment ID: 21285

Commenter Name: Sandi Tabo r Letter ID: 0162 Commenter Or g anization: Li g nite Ener gy Council (LEC) Comment ID: 21294The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable fo r GS. Additionally, many of the permit requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testing and monitoring, and injec tion well plugging and post- injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Dir ectorial discretion and considerations for how that discretion would be exercised. The Agency believes th is balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each project, while providing consistency in permitting across the U.S.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Comment: Principles for new regulations

§ Because of the difficulty of regulati ng future activities, we urge EPA to continue to use a "performance based" a pproach in developing the requirements for Class VI UIC wells. This way, rules can be readily adjusted and fine-tuned as industry and regulators alike gain experience with large-scale CO2 sequestration.

§ Because information and technology relate d to carbon sequestration will evolve as industry and regulators gain experience with CCS, NRECA urge s EPA to resist
p lacing blanket prohibitions or detailed ope rational specifications in the Final Rule.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary. Commenter Name: James Stine Letter ID: 0163 Commenter Or g anization: National Rural Electric Cooperative Association (NRECA) Comment ID: 21313

Commenter Name: James Stine Letter ID: 0163 Commenter Or g anization: National Rural Electric Cooperative Association (NRECA) Comment ID: 21320Comment: COMMENTS

1. NRECA acknowledges EPA's efforts to use a "performance-based" approach and to build flexibility into the Proposal, incl uding the use of directorial discretion and the provision for forthcoming guidance to clarify other requirements. In general, we agree that these methods wi ll help create a re gulatory framework that can evolve as information and technological advancements are gained in the field of carbon capture and sequestration. It is important, however, that any directorial discretion be clearly defined and limite d; this can be achieved while still maintaining a rule that is flexible and avoids unnecessary
p rohibitions. In addition, guidance on any aspect of the Final Rule (for example, clarification of requirements for financial assurance mechanisms) must be developed in accordance with OMB’s Good Guidance Practices Bulletin, which directs that notice and comment be pr ovided on "economically significant" guidance documents. See 72 Fed. Reg. 3432, 3438 (Jan. 25, 2007).

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA is developing guidances for States that descri be the process of applyi ng for and receiving primary enforcement authority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum federal criteria and requirements. The guidance will describe area s of Directorial discretion and considerations for how that discretion would be exercised. This guidance wi ll be available on EPA’s website at http://water.epa.gov/t ype/groundwater/uic/wells_sequest ration.cfm. EPA has taken OMB’s Good Guidance Manual into consideration as it de veloped the guidance. OMB’s Good Guidance Manual establishes policies and procedures for the devel opment, issuance, and use of significant guidance documents by Executive Branch departments and agencies.

Comment: EPA, in this rulemaking, must establis h a cost-effective and environmentally sound regulatory program to cover a range of operations in order that the technology will be commercial ly deployed. To meet this challenge and establish a workable regulatory framework over the coming decades for the long-term storage of CO2, it is imperative that EPA take care to craft the regulations with flexibility so that they ma y be fine-tuned as industry and regulators alike gain experience with the large-scale CO2 sequestration contemplated by this rulemaking. APPA applauds EPA’s efforts to build such flexibility mechanisms into the Proposed Rule, including the use of state directorial discretion and the provision for forthcoming guidance to clarify other requirements. APPA agrees that both of these methods will help create a regulatory framework that can evolve as information and technological advancements are gained in the field of carbon capture and sequestration. Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23394Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA clarifies that the intent of the Class VI regula tions is not to promote or encourage the use of GS, but, instead to ensure protection of USDWs wher e GS technologies are deployed. EPA is using an adaptive approach to regulating GS under the UIC Progr am. Even after finalization of the GS regulation, EPA plans, every six years, to co llect and review project data on GS research projects to determine whether the appropriate amount and types of info rmation and appropriate documentation are being collected, and to determine if m odifications to the requirements are appropriate or necessary.

Comment: · Because the technology described in the Proposal will not be commercially and widely deployed (in states without oil and gas production) for perhaps as long as 30 years, the Final Rule must be flex ible enough to accommodate developments in information and technology rela ted to carbon sequestration. These developments could reflect knowledge that affirms the technology and minimizes any cautions or concerns expressed by APPA regarding USDW risk, liability, etc.

· APPA is really not qualified to comments on site selection or well construction or injection procedures. APPA defers to decision making by the state directors (or EPA in the case of non-delegated states on these aspect). EPA’s Final Rule should keep as many opt ions regarding site and method of injection available, subject to the standa rd that any CO2 GS be protective of underground sources of drinki ng water ("USDWs").

Response: As described above, EPA believes the rule pr ovides flexibility to address site-specific conditions. EPA is using an adaptive approa ch to regulating GS under the UIC Program.

Comment: API shares the same goal as EPA: to de velop rules that facilitate the safe, secure longterm storage of CO2. API is concerned though that by being overly restrictive in designing the new well cla ss, the proposed rule will hinder the deployment of CCS and could have the unant icipated consequence of hindering the innovations that could improve both well security and performance. CCS is likely to be of one of the core technologies th at could help to ensure that we can continue to produce the clean energy soci ety demands. API would be eager to

Response: EPA agrees that permitting deci sions for GS wells should be ba sed on site-specific factors. The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable for GS. Additionall y , man y of the permit Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23402

Commenter Name: K y le Isakowe r Letter ID: 0170 Commenter Or g anization: American Petroleum Institute Comment ID: 24132requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testing and monitoring, and injec tion well plugging and post- injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Dir ectorial discretion and considerations for how that discretion would be exercised. The Agency believes th is balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each project, while providing consistency in permitting across the U.S.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Comment: Comments Regarding UIC Regulations

1. Due to the difficulty and uncertainty of regulating future activities, we urge EPA to continue to use a "performance based" ap proach in developing the requirements for Class VI UIC wells. This way, rules can be readily adjusted and fine-tuned as industry and regulators alike gain experience with large-scale CO2 sequestration. It is also important to main tain the flexibility for a site-based approach when addressing the requireme nts for Area of Review evaluations, operational monitoring and post inje ction care and closure periods.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than sett ing performance- or technology-ba sed standards for GS projects, EPA is adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: 2. Information and technology related to carbon sequestration will evolve as industry and regulators gain experience with CCS. GRE feels EPA should resist
p lacing blanket prohibitions or detailed ope rational specifications in the Final Rule.

Response: As described above, the Agency believes that the Class VI requirement s balance site-specific flexibilit y with USDW protection. EP A adds that it is usin g an adaptive approach to re g ulatin g GS under Commenter Name: Erik Silvola Letter ID: 0171 Commenter Or g anization: Great River Ener gy Comment ID: 23440

Commenter Name: Erik Silvola Letter ID: 0171 Commenter Or g anization: Great River Energy Comment ID: 23441the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether th e appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

Comment: State Standards, Regulations, F unding, and Primacy Requirements

State Flexibility Needed:

The flexible regulatory approach that is built into the proposed rule appears to adequately provide for state implementati on efforts to address site specific circumstances and assure that the rule is implemented toward the highest degree of protection for USDWs. However, the rule should also allow for state flexibility with regard to existing state standards and regulations, if they are more stringent (i.e., regarding well construction requirements) than the Federal rule.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

In response to the comment that States with primacy be able to develop “performance-based standards,” the Agency clarifies that States, Tribes, and Terr itories can develop require ments for Class VI and submit primacy applications (under Section 1422 of the SDWA) for review and approval by EPA as long as the requirements are as stringent as or more stringent th an the Federal minimum requirements.

Comment: • Because the technology described in the Proposal will not be commercially deployed for a number of years, the Final Rule must be flexible enough to accommodate developments in information and technology related to carbon sequestration. Similarly, because there is li kely to be a significant amount of CO2 available for sequestration under the Program, the Final Rule should avoid arbitrary absolutes or blanket prohibitions regarding site selection or well construction or injection procedures. The Final Rule should keep available as many options as possible for site selection and method of in jection, subject always to the standard that any CO2 GS be protective of USDWs.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPA is adoptin g a flexible approach, where operators of GS pro j ects would develop and implement siteCommenter Name: James Taft Letter ID: 0172 Commenter Or g anization: Association of State Drinki ng Water Administrators (ASDWA) Comment ID: 23456

Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utility Solid Waste Ac tivities Group (USWAG) Comment ID: 23461specific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: • Because carbon sequestration technology is still developing and the characteristics and limitations of CO2 GS projects will vary greatly from one site to another, it is essential to inco rporate performance-based standards into the Final Rule, leading to a site-tailored approach to requirements for Area of Review ("AoR") reevaluation and post-inje ction site care and closure periods.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA adds that it is using an ad aptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Other EPA Comment Codes and Descriptions: 2400 1.8 Comments on EPA's adaptive rulemaking
p rocess Comment: 2. Necessity of a Flexible Regulatory Scheme

USWAG applauds the efforts EPA has take n thus far to instill certainty and transparency in the future Class VI CO2 regulatory regime . 73 Fed. Reg. at 43496. At the same time, it is imperative that the Final Rule reflect the challenges inherent in crafting regulations for commercial CO2 injection activities when large-scale commercial ope rations are only at the nascent stage. The challenge confronting EPA in this rulemaking is to establish a costeffective and environmentall y protective re g ulator y pro g ram to cover a ran g e of Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utilit y Solid Waste Activities Group (USWAG) Comment ID: 23462

Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utility Solid Waste Ac tivities Group (USWAG) Comment ID: 23473operations for which the technology will not be commercially deployed for a number of years.

To meet this challenge, it is critical that the Final Rule emphasize
p erformance-based rules that can be readily adjusted and fine-tuned as industry and regulators alike gain experience with large-scale CO2 sequestration. USWAG acknowledges EPA's efforts to build flexibility mechanisms into the Proposal, including provisions for di rectorial discretion and the suggestion that forthcoming guidance may be used to clarif y other requirements. In general, we agree that these methods will help create a regulatory framewor k that can evolve as information and technological advancemen ts are gained in the field of carbon capture and sequestration. It is import ant, however, that any directorial discretion be clearly defined and limited; this can be achieved while still maintaining a rule that is flexible and avoids unnecessary prohibitions. In addition, guidance on any aspect of the Fina l Rule (for example, clarification of requirements for financ ial assurance mechanisms) must be developed in accordance with OMB's Good Guidance Pract ices Bulletin, which directs that notice and comment be provided on " economically significant" guidance documents.[FN2] See 72 Fed. Reg. 3432, 3438 (Jan. 25,2007).

Because information and technology related to carbon sequestration will develop as industry and regulators gain experience with CCS, USWAG urges EPA to avoid blanket prohibitions or arbitrary absolute s in the Final Rule. We agree that the appropriate standard underlying the techni cal requirements for CO2 GS wells is the protection of USDW s. However, because it is difficult to know at this point what methods or technology will be devel oped for injection and long-term storage of CO2 in a manner that is protective of USDWs - and because there is sure to be demand for significant capacity for CO2GS - EPA should not prematurely preclude the use of specific types of sites or methods for Class VI CO2 injection. The Final Rule should leave the door open for a range of injection sites and methods (some of which are unknown or not yet full y understood), provided that the Owner or Operator can show that the injection a nd storage will be protective of USDWs.

[FN2] The Bulletin defines "economically significant guidance document" as "a significant guidance document that 'may reas onably be anticipated to lead to' an annual effect on the economy of $100 million or more or adversely affect in a material way the economy or a sector of the economy." See 72 Fed. Reg. at 3435.

Response: EPA recognizes the importance of providing clear, flexible, scalable, and appropriate regulations. The final GS rule incl udes a balance of specific criteria to be met by the owner or operator and areas of Directorial di scretion. The Agency believes this bala nce allows for GS projects to be designed and permitted to address the unique, site-s pecific aspects of each project, while providing consistency in permitting across the U.S. EPA is de veloping guidances for stat es that describe the
p rocess of applying for and receiving primary enfor cement responsibility (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the tec hnical and administrative issues on developing GS regulations that are the equivalent of minimum federal criteria a nd requirements. The guidance will
p rovide recommended approaches fo r how permitting authorities may exercise Director's discretion. The guidance will be available on EPA's web site, at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

EPA also agrees that an adaptive approach to rule making for GS is appropriate. The Agency plans to usesuch an approach to ensure that USDWs are protected from endangerm ent and meet the potentially fast
p ace of GS deployment. EPA believes that an adaptive approach will allow regulatory development to
p roceed in time to meet the current and future demand for Class VI permits while recognizing the need to: continue to gather data from pi lot projects and other research as it becomes available; and to enhance understanding of the technical and administrative aspects of GS deployment, operation, and technology developments. EPA plans, every six years, to coll ect and review data on GS projects to determine whether the appropriate amount and types of info rmation and appropriate documentation are being collected, and to determine if modifications to the requirement s are appropriate or necessary.

EPA disagrees that the GS rulemaking needs to be based solely on larg e-volume projects. While studying the impact of injecting la rge volumes of CO2 is important , data on other aspects of GS— including the buoyancy and corrosivity of CO2 in the presence of wa ter, the potential presence of impurities in captured CO2, and its mobility within subsurface formations —informed the rulemaking.

Comment: Proposed requirements for well drilling, c onstruction, and other characteristics With respect to many of the proposed re quirements, USWAG believes it is imperative to craft the Final Rule as a flexible instrument that establishes
p erformance-based standards, which can be achieved through a variety of methods as long as there is a sound technical basis underlying each method and assuring its protection of USDWs. See id. at 43508-09. Because this technology is years from commercial deployment and is still developing, the Final Rule should allow for the use of technologies and methods th at are not yet developed or are only in the beginning stages, provided that they are shown to be protective of USDWs.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Other EPA Comment Codes and Descriptions: 3840 2.3.2 Horizontal well drilling techniques (seeking comment) Comment: This logic also applies to argue against a prohibition on any type of well drilling, whether horizontal, vertical, or angled. Id. at 43509. There will likel y be a need to maximize capacit y for CO2 GS, and it would be premature at Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utilit y Solid Waste Activities Group (USWAG) Comment ID: 23491

Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utility Solid Waste Ac tivities Group (USWAG) Comment ID: 23492this point to impose a blanket prohibiti on on any type of well drilling without knowing whether that drilling could be done in a manner that is protective of USDWs.

Response: In the final rule, EPA allows the use of horizont al wells at GS projects. In the proposed rule, EPA sought comment on the appropriateness of horizontal drilling techniques for Class VI wells, and commenters representing energy compan ies, electric utilities, the oil and gas industry, CCS associations, states, and the public, unanimously supported the concept and provided many reasons why horizontal wells could be beneficial at GS sites. Based on an evaluation of these comments and additional research by EPA, the Agency has concluded that horizontal wells that are properly constructed, logged, and tested for mechanical integrity (i.e ., to meet the requirements of the GS rule) can ensure the protection o f USDWs from endangerment.

Comment: Flexibility

EPA states throughout the proposal that fl exibility in the application of the rule is essential to balancing the prot ection of USDW against the need to facilitate CCS development and commercialization. Accordingly, Dominion urges EPA to recognize that no tw o GS sites are identical a nd that requirements that may be appropriate for one site may be prohibitive for another site. While directorial discretion is a us eful mechanism to ensure flexibility in the Final Rule, such discretion must be clearly defined and limited.

Response: EPA agrees that permitting deci sions for GS wells should be ba sed on site-specific factors. The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable fo r GS. Additionally, many of the permit requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testing and monitoring, and injec tion well plugging and post- injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Dir ectorial discretion and considerations for how that discretion would be exercised. The Agency believes th is balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each project, while providing consistency in permitting across the U.S.

EPA is developing guidances for States that descri be the process of applyi ng for and receiving primary enforcement authority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum federal criteria and requirements. The guidance will describe area s of Directorial discretion and considerations for how that discretion would be exercised. This guidance wi ll be available on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm.

Comment: Adaptability

The Agency should strive to anticipa te future statutory and regulatory developments in the climate chan g e arena so that an y rulemakin g has a reasonable Commenter Name: Pamela Fa gg ert Letter ID: 0175 Commenter Or g anization: Dominion Comment ID: 23515

Commenter Name: Pamela Faggert Letter ID: 0175 Commenter Or g anization: Dominion Comment ID: 23516chance of facilitating such developments. EPA can and should consider how its UIC rulemaking will fit with foreseeable features of potential future regimes and how rules can be drafted to complement such features to the extent possible. Additionally, because it is difficult to know at this point what methods or technology will be developed for injection and long-term storage of CO2, coupled with projected demands for capacity, EPA should not prematurely preclude the use of specific types of sites or methods for Class VI CO2 injection.

Response: EPA is using an adaptive approach to re gulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: "Tailored requirements," as opposed to more general or more specific requirements, are preferable as they provide adequate protection while simultaneously allowing for the flexibil ity to address local geology and sitespecific conditions and to embrace evolving technology. Tailored requirements should be brought to bear when considering the nine specific topical areas for addressing the proposed Cla ss VI UIC requirements:

1. Geologic Siting;

2. Area of Review and Corrective Action;

3. Injection Well Construction;

4. Injection Well Operating;

5. Mechanical Integrity Testing;

6. Plume and Pressure Front Monitoring;

7. Recordkeeping and Reporting;

8. Well Plugging, Post-Injec tion Site Care, and Site Closure; and

9. Financial Responsibility and Long-term Care.

Response: EPA agrees that permitting deci sions for GS wells should be ba sed on site-specific factors. The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable fo r GS. Additionally, many of the permit requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testing and monitoring, and injec tion well plugging and post- injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Dir ectorial discretion and considerations for how that discretion would be exercised. The Agency believes th is balance allows for GS projects to be designed and permitted to address the unique, site-sp ecific aspects of each pro j ect, while providin g consistenc y in permittin g Commenter Name: Kenneth Nemeth Letter ID: 0176 Commenter Or g anization: Southern States Ener gy Boar d Comment ID: 23541across the U.S. Please see the final rule and pr eamble for additional information on EPA's final regulatory approach.

Comment: 2. Avoidance of one-size-fits-all appr oaches. As currently proposed, EPA‘s regulations contain a number of default pr ovisions that would apply universally to projects, at least as a matter of initial presumpt ion. Rather than imposing default provisions, those portions of the rulemaking that address inherently site-specific issues shoul d allow for site-specific, performance-based determinations as part of the permitting process. The geologic variability involved in different concei vable GS projects needs to be taken into account in issues ranging from site characterization to area of review (AOR ) to containment requirements.

Response: EPA believes that the Class VI requirements balance site-specific fl exibility with USDW
p rotection. Rather than setting performance or t echnology-based standards for GS projects, EPA is adopting a flexible approach, where operators of GS projec ts would develop and im plement site-specific
p lans for delineating the AoR, te sting and monitoring the site, pe rforming corrective action, and postinjection site care. EPA believes that the plans—wh ich would be reviewed a nd approved by the Director and periodically updated throughout th e life of the project—promot e an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a particular
p roject. Please see the final rule and preamble for additional information on EPA's final regulatory approach.

Comment: 3. Importance of limits on discretion. EEI recognizes that in order to allow for effective site-specific determinations and to maintain essential regulatory flexibility, some amount of discretion must be vested in the UIC program director. At the same time, such disc retion should be bounded by the inclusion of relevant and appropriate considerati ons for making necessary determinations. In general, the rules should establish with sufficient clarity the factors to be taken into account and leave the precise de terminations to the permit process.

Response: EPA is developing guidances fo r States that describe the process of appl ying for and receiving primary enforcement au thority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum fede ral criteria and requirements. The guidan ce will describe ar eas of Directorial discretion and considerations for how that discretion would be exercise d. This guidance will be available on EPA’s website at http://w ater.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: Siting requirements should reflect that conditions affecti ng risk differ by site. The y need to be tailored to the actual risks presented b y specific sites. Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23570

Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23571

Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23853EOR is a well developed te chnique and there is now a history through which its risks can be assessed. This differs from injection for long-term storage in deep saline formations or unmineable coal seams. with which there is little experience, particularly on the massive sc ale (e.g., a million or more tons per year per plant) envisioned for the future . For CCS to be a viable long-term strategy, policy must encourage developmen t of data about these sites, new technology. and new practices.

Response: EPA agrees with the commenter that every si te (and the risk posed) is unique. EPA agrees that site characterization should be site-specific, particularly in light of the variety of geologic settings in which GS may be employed. EPA believes that, whil e there is a large amount of required information, the owner or operator is given flex ibility in determining what met hods are used to demonstrate the suitability of a potential site. EP A envisions an ongoing dialogue betwee n the Director and the owner or operator during the permitting pr ocess (as well as throughout the operation of the site).

Comment: specifics that remain to be dealt with. With respect to suggested modifications, I find that the draft regulations are overly prescriptive on several points and not sufficiently performance based. With re spect to some specific requirements, the objectives are not well defined such that re quired performance would be difficult to determine. I would urge the U.S. EPA to take all comments received and reissue a set of revised proposed re gulations for further comment before finalizing Class VI regulations. My comm ents address specific points in the draft regulations, as outlined below.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Comment: - The final rule must be flexible and stru ctured such that it has the ability to respond appropriately to the developmen t of future carbon sequestration technologies. In this regard, performance -based standards allowing for a site tailored approach are critical.

Response: EPA is using an adaptive approach to re gulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary. Commenter Name: Robert J. Finle y Letter ID: 0180 Commenter Or g anization: Illinois State Geolo g ical Surve y Comment ID: 23617

Commenter Name: Scott Davis Letter ID: 0187 Commenter Or g anization: Arizona Public Service Compan y Comment ID: 25221Other EPA Comment Codes and Descriptions: 2400 1.8 Comments on EPA's adaptive rulemaking
p rocess Comment: Recognizing that a great deal of this technology is currently in development and will not be commercially deployed for seve ral years, it is vital that the final rule, if necessary, include reasonable perfo rmance based regulations that can be swiftly adjusted and finetuned as experi ence is gained in large-scale CO2 GS. The promulgation of this rule is only but the first step in the establishment of a regulatory framework to support the impl ementation of GS as the technology is scaled up from the current experimental stage to fully operational wells, considerable experience will be gained that would help further identify areas where adjustments to the rules would be necessary. Therefore, we recommend a two
p hase regulatory approach. The first phase would be to address initial projects where operational experience and familiarity with carbon injection and storage can be gained. That knowledge, includi ng lessons learned from the both the technical and regulatory perspective, could then be utilized to develop a second
p hase rule that would more likely be able to provide a better balance between risks with regulatory requirements.

Response: EPA agrees that an adaptive approach to th e UIC GS rulemaking is appropriate. The Agency
p lans to use such an approach to ensure that USDWs are protected from endangerment and meet the
p otentially fast pace of GS deployment. EPA believes that an adaptive approach will allow regulatory development to proceed in time to meet the current and future demand for Class VI permits while recognizing the need to: continue to gather data from pilo t projects and other re search as it becomes available; and to enhance understanding of the techni cal and administrative as pects of GS deployment, operation, and technology developments.

EPA plans, every six years, to collect and review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requi rements are appropriate or necessary.

EPA disagrees that the GS rulemaking needs to be based solely on larg e-volume projects. While studying the impact of injecting la rge volumes of CO2 is important , data on other aspects of GS— including the buoyancy and corrosivity of CO2 in the presence of wa ter, the potential presence of impurities in captured CO2, and its mobility within subsurface formations—i nformed the rulemaking.

Other EPA Comment Codes and Descriptions: 1260 1.1.1.5 More certainty/stringency is needed Comment: 4. For an activity covering such a diverse geographic, geologic, and commercial spectrum as GS, NiSource be lieves it is essential to incorporate considerable regulatory flexibilit y. However, some relatively high minimum st andards of technical requirements should be establis hed in key areas. While this may sound contradictory, NiSource's observation is th at firmly addressi ng those few real risks will ultimately pay significant dividends by preventing a few "bad"
p rojects from being developed that ultimately lead to an avoidable incident that taints the entire industry. These issues are addressed below.

Response: The A g enc y believes that the Class VI require ments balance site-s pecific flexibilit y with Commenter Name: Daniel Plath Letter ID: 0188 Commenter Or g anization: NiSource, Inc. Comment ID: 25226

Commenter Name: Daniel Plath Letter ID: 0188 Commenter Or g anization: NiSource, Inc. Comment ID: 25232USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Comment: 1. Because of the difficulty of regulating future activ ities, Oglethorpe urges EPA to continue to use a "performance based" approach in developing the requirements for Class VI UIC wells. This way, rules can be readily adjusted and fine-tuned as industry and regulators alike gain experience with large-scale CO2 sequestration.

2. Because information and technology re lated to carbon sequestration will evolve as industry and regulators gain e xperience with CCS, Oglethorpe Power strongly encourages EPA to resist placi ng blanket prohibiti ons or detailed operational specifications in the Final Rule.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: To achieve its goals for this rulemaking - to address the risks of CO2 injection and promote the development of GS - EPA mu st take a hard look at the need for, and practical utility of, each of the requirements it has proposed for CO2 injection. As further detailed in these Comments, we believe that the proposed requirements can and should be streamli ned significantly to increase the flexibility of the requirements for CO 2 injection and reduce the unnecessary (and ultimately counterproductive) regulat ory burdens the proposed rule would impose. We respectfully urge EPA to modify its propos ed regulatory approach accordingly. Commenter Name: G. Graham Holden Letter ID: 0189 Commenter Or g anization: Oglethorpe Power Corporation Comment ID: 25246

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24318Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Other EPA Comment Codes and Descriptions: 1410 1.2.1 Comments in support of EPA/rulemaking Comment: We support EPA’s conclusion that the UI C program provides an appropriate framework for regulation of carbon dioxide (CO2) injection for geologic sequestration (GS). The UIC program govern s a very wide range of underground injection activities - including the ope ration of thousands of existing CO2 injection wells - and enjoys an extensively documented record of success. The
p rogram has in many respects been a mode l for Federal-State cooperation, and has benefited from a long history of regul atory and technical discourse among agencies and regulators ar med with considerable practical experience and exceptional technical expertise. Whil e the UIC program is focused on the
p rotection of "underground s ources of drinking water" (U SDWs), this seemingly narrow objective is narrow in name only. In fact, the measures the UIC program relies upon to protect USDW s - measures designed to ensure that injected material remains isolated in the deep subsurface - are by nature sufficient to ensure protection of human health and the environment.

The UIC program currently provides regulations that can be (and are being) successfully applied to CO2 injection into oil and gas reservoirs. We also agree that it makes sense to develop regulations more specifically de signed to address CO2 injection in the GS context especially for formations that are not oil and gas reservoirs. Such regulations can and s hould be designed to build on relevant UIC program experience, including experien ce with CO2 injection, and should be tailored to address the particular n eeds for this category of injection activity: both the need to protect USDWs and the need to facilitate use of GS as a technology for reducing CO2 emissions. Those regulations should follow a flexible, performance-based approach that allows regulators to tailor specific
p ermit requirements as appropr iate based on the broad ra nge of injection sites and practices that may be encountered in the GS context and on the body of knowledge and experience that will be gained not only from pilot and demonstration projects, but from the in itial deployment of commercial scale geologic sequestration projects.

Moreover, the safeguards of the UIC program have been adequate to protect USDWs of all types, including sole source aqui fers, from injection that occurs substantially below those aquifers even where that involves drilling through the aquifer to construct wells that will in ject into deeper formations. These drilling activities have not resulted in any significant contamination of sole source aquifers and, indeed, have probably served to protect those aquifers by avoidin g surface disposal operations that would have been more likel y to pose Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24319threats of endangerment to dr inking water resources.[FN1]

[FN1: Each year, industrial facilities and municipal wastewater treatment
p lants generate bill ions of gallons of hazardous and no n -hazardous waste. Class I injection wells provide a safe means to remove these wastes from the surface environment by isolating th em deep below the land surface, away from drinking
water resources.

Class I injection wells inj ect far below the lowermos t USDW. Injection zones typically range from 1,700 to more than 10,000 feet in depth. The injection zone is separated from USDWs by an impermeable "cap" rock ca lled the confining layer, along with additional layers of permeable and impermeable rock and sediment that separate the injection layer from the USDW.

http://www.epa.gov/safewater/ uic/wells_class1.html]

Response: EPA acknowledges the comment and believes that the creation of a ne w injection well class (VI) under the existing UIC Program is necessary to en able the use of GS as a climate change mitigation technology in a manner that protects USDWs from endangerment. EPA agrees that the UIC Program, under the authority of the SDWA, provides a strong fr amework for regulating in jection of CO2 for GS and adds that the GS regulation tail ors the UIC requirements to address the unique issues associated with large-scale GS including large inj ection volumes, the relative buoyancy of CO2, its corrosivity in the
p resence of water, the potential presence of impurities in capture d CO2, and its mobility within subsurface geologic formations.

EPA agrees that the implem entation of the GS rule in a manner that ensures protection of USDWs from endangerment is important to esta blishing a foundation for further adva nces in the field of CO2 GS. EPA acknowledges the need for regulatory certainty: the final GS requirements provide a level of certainty by setting forth unique requirements for GS. These require ments include: the tailored AoR delineation process at §146.84, the types of monito ring appropriate to GS projects at §146.90 and the
p ost-injection site care process at §146.93. For additiona l information on these requirements, please also see the discussion of EPA’s Final Regulatory Appr oach in the preamble to the final GS rule.

To protect USDWs from endangerment and meet the potentially fast pace of GS deployment, EPA is using an adaptive approach to re gulating CO2 injection for GS. The Ag ency plans to collect and review data every six years on GS projects to determin e whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or nece ssary. An adaptive approach will allow regulatory development to
p roceed in time to meet the current and future demands for Class VI permit s while EPA continues to gather data from pilot projects and othe r research as it becomes available.

Other EPA Comment Codes and Descriptions: 1210 1.1.1 Comments about the proposed rule; 1420 1.2.1.1 Support the GS rulemaking Comment: Protection of U.S. Drinking Water (USDW) sources is paramount and a central requirement of the Safe Dr inking Water Act and ConocoP hillips wholeheartedly supports high standards for protection of cu rrent and potential future USDWs. We believe that maintaining focus on several key principles can ensure rulemaking that is protective and flexible to al low site specific considerations while Commenter Name: Jeff W. Sheets Letter ID: 0192 Commenter Or g anization: ConocoPhillips Comment ID: 23887maintaining cost-effective operations. We applaud EPA's work to that end. We support most concepts, elements and deta ils in the proposed requirements, and
p rovide our comments to reinforce and amplify a few issues which we believe flow from the following importa nt key principles:

o All UIC well classes have requirement s fully designed to protect USDW's.

o The oil and gas industry's experience with CO2 injection for enhanced oil recovery (EOR) provides a track record of USDW protection that can enhance EPA's rulemaking.

Response: EPA believes that the creation of a new in jection well class (V I) under the existing UIC Program is necessary to enable the use of GS as a climate change mitigation technology in a manner that
p rotects USDWs from endangerment. EPA agrees th at the UIC Program, under the authority of the SDWA, provides a strong framework for regulating injection of CO2 for GS and adds that the GS regulation tailors the UIC requirements to address the unique issues associated with large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurit ies in captured CO2, and its mobili ty within subsurface geologic formations.

EPA recognizes that the oi l and gas industry has decades of experi ence injecting CO2 for the purpose of ER, and that sites used for ER may be suitable for GS and may be among the first GS sites. Some of the research that informs the final GS rule was conducted at ER sites. EPA also recognizes that a by-product of ER activities is that a certain percentage of the CO2 is trapped in the receiving formation.

Comment: o Performance standards should focus on containment while allowing for flexibility as more is learned about CCS. An approach which is overly
p rescriptive reduces learning, risks delaying the use of newer/better alternatives in the future, and can add unnecessary costs.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Comment: FLEXIBLE REGULATORY SCHEME

Ameren generally supports the creation of Class VI, a new class of injection wells for CO2 injection and storage. We also appreciate the attempt that EPA has taken to bring "certainty" and "trans parency" to the future CO2 underground in

j ection re g ulator y re g ime. However, it is imperative that the Final Rule be Commenter Name: Jeff W. Sheets Letter ID: 0192 Commenter Or g anization: ConocoPhillips Comment ID: 23889

Commenter Name: Paul Pike Letter ID: 0198 Commenter Or g anization: Ameren Corporation Comment ID: 23938flexible enough to deal with the currentinvestigative phase and when largescale commercial operations are in place. We recognize that GS has significant
p otential to be a major portion of any fu ture CO2 emission reduction scheme, but that can only occur if the regulations adapt to the actual hazard posed by the technology which may not be fully underst ood until some time in the future.

Clearly the Agency understands the need for flexibility by allowing a Director to provide guidance on regulatory compliance. We understand that this can allow the regulatory framework to evolve; however, there also needs to be some definition and limits to that discreti on so that the public and regulated community can provide comments on that guidance. This means that technical and financial aspects are considered in the development of guidance.

We also recognize that the underlying basis for these regulations is the
p rotection of underground sources of drinking water ("USDWs"), but we urges EPA to avoid blanket prohibitions or arbitrary absolutes in the Final Rule. It is impossible to know what methods or technol ogy will be devel oped for injection and long-term storage of CO2 and the Agen cy should not prematurely preclude the use of specific types of sites or methods for Class VI CO2 injection. The Final Rule should allow a range of injection sites and methods, provided that the Owner or Operator can show that the injection and storage will be protective of USDWs.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA is developing guidances for States that descri be the process of applyi ng for and receiving primary enforcement authority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum federal criteria and requirements. The guidance will describe area s of Directorial discretion and considerations for how that discretion would be exercised. This guidance wi ll be available on EPA’s website at http://water.epa.gov/type/g roundwater/uic/wells _sequestration.cfm.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Comment: emissions. It is critical, therefore, that EPA promulgate fl exible regulations that can develop as industr y and regulators alike gain experience with largescale CO2 sequestration. These regulations should be built around performancebased standards that encourage tailoring of the Program's requirements to the
g eolo g ic and technical needs of a g iven CO2 GS site. Commenter Name: Chris M. Hobson Letter ID: 0201 Commenter Or g anization: Southern Compan y Comment ID: 22154Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA adds that it is using an ad aptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Other EPA Comment Codes and Descriptions: 1610 1.3.1 Risks to USDWs Comment: Southern Company agrees that the appropr iate standard underlying the technical requirements to be applied to Class VI wells should be the protection of underground sources of drinking water (" USDWs"). See id. at 43497. With this standard in mind, it is imperative th at EPA fashion the Final Rule with sufficient flexibility to meet two primary goa ls: first, adequa tely addressing the varied geologic conditi ons of different CO2 GS sites; second, ensuring adaptability as industry a nd regulators gain experience with and information regarding CO2 GS. It is important that the Final Rule not exclude the existing experience and knowledge gained from current CO2 injection and GS demonstration
p rojects. To encourage use of this in formation, Southern Company supports facilitated GS in oil and gas reservoirs with the protection of USDWs and the transition of Class II and Class V C02 injection operat ions to GS. The Final Rule should establish a re gulatory framework built around the standard of
p rotecting USDWs while allowing Directors to issue permits with site-specific requirements. An emphasis on site selec tion, site characteri zation, and careful
p ermit-writing will further strengthen a regulatory scheme that will provide
p rotection of USDWs while maximizing the beneficial environm ental and economic impacts of carbo n sequestration.

Response: EPA notes that the final rule does allow owne rs or operators flexibility. EPA has taken a regulatory approach that promotes USDW protection, incorporates flexibility or the discretion of the
p ermitting authority when appropriate, seeks to li mit burden on owners or operators and permitting agencies, and provides a foundation for national consis tency in permitting of GS projects. Many Class VI permit requirements must be established through site -specific plans devel oped by the owner or operator and approved by the Director. Consequently, EPA anticipates that owners or operators will consult with the Director as they develop, implement, and update these plans. In addition, the final rule affords the Director flexibility to approve alternatives to the requirements in some cases. For example, the Director may in certain situati ons modify the length of the post-inje ction site care period or approve an alternative post-inject ion site care timeframe as part of the permitting process under §146.93, allow the use of alternate methods for mechanical integrity testing (if approved by EPA), and waive the requirement that wells be desi g ned to in j ect below the lowermost USDW. Commenter Name: Chris M. Hobson Letter ID: 0201 Commenter Or g anization: Southern Compan y Comment ID: 22155EPA recognizes that technol ogies will evolve and improve over ti me, and for these reasons, the Agency is using an adaptive approach to regulate GS injection. The Agency plans, every six years, to collect and review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

EPA is allowing the construction of Class II and V well s to be re-permitted as Class VI wells pursuant to §146.81(c), provided the owner or operator can demons trate to the Director that the wells were engineered and constructed to m eet the requirements at §146.86(a) and ensure protection of USDWs, in lieu of requirements at §146.86(b) and §146.87(a). EPA believes that allowing for grandfathering of select construction requirements, if approved by the Director, will ease th e transition to Class VI from an existing ER project while protect ing USDWs from endangerment.

EPA clarifies that the GS rule does not promote GS in specific settings, nor does it limit injection activities to any specific type of formation, geographi c region, or depth. The focus of the GS rule is to ensure that, where GS is deployed, it is conducte d in a manner that is protective of USDWs.

Comment: The Proposal includes many provisions for di rectorial discretion that will help ensure that the C02 GS program has the flexibility it needs to succeed. While EPA must take care to clearly define the circumstances in which directorial discretion may be exercised and to limit the scope of that discretion, in many cases this discretion will allow Di rectors to consider the unique characteristics of a given CO2 GS projec t and adopt a site-specific approach that will meet the Final Rule's performance-based standards.

Response: EPA is developing guidances fo r States that describe the process of appl ying for and receiving primary enforcement au thority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum fede ral criteria and requirements. The guidan ce will describe ar eas of Directorial discretion and considerations for how that discretion would be exercise d. This guidance will be available on EPA’s website at http://w ater.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Comment: Operating and Monitoring Requirements

It is important to reiterate that, because CO2 GS technology is still developing, additional information will be gained and technological advancements made that will allow Owners or Operators to make use of a broader range of tools and methods in Class VI well operation wh ile being fully protective of USDWs. For example, our pilot projects as part of the Southeast Carbon Sequestration Regional Partnership will lead to greate r technical expertise related to CO2 injection. In addition, the ge ologic characteristics and li mitations of Class VI wells will vary significantly from site to site. For these reasons, the Final Rule should be flexible enough to incor porate new information and technological advancements which, in turn, will help promote a more robust and environmentall y Commenter Name: Chris M. Hobson Letter ID: 0201 Commenter Or g anization: Southern Compan y Comment ID: 22156

Commenter Name: Chris M. Hobson Letter ID: 0201 Commenter Or g anization: Southern Compan y Comment ID: 22170p rotective CO2 injection program. To achieve this result, the Final Rule should establish performance-based standards and allow permit applican ts and Directors to work together to fashion a plan that wi ll best suit the needs of a particular Class VI site and any associated USDWs.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA adds that it is using an ad aptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Other EPA Comment Codes and Descriptions: 1420 1.2.1.1 Support the GS rulemaking Comment: Southern Company applauds the EPA's in itial efforts to create a clear and flexible regulatory scheme that will promote carbon capture and storage technology and projects while protecting underground sources of drinking water. We appreciate the opportunity to comment on this rulemaking and look forward to continuing to work with EPA on this important issue.

Response: As described above, EPA agrees that the UIC Program, under the authority of the SDWA,
p rovides a strong framework for regulating injection of CO2 for GS.

Comment: As one of the largest coal-fired generators of electricity in the U.S., and as a likely user of GS to reduce CO2 emissions, this rulemaking will have a direct impact on Duke Energy and its customers. As an entity whose operations will be directly impacted by the rule, Duke Energy encourages EPA to provide as much flexibility as possible while maintaining appropriate environm ental safeguards. For example, the characteristics of potenti al GS sites will be highly variable. EPA should provide flexibility by avoiding a one-size-fits-all approach. This can be done by incorporating performance-based standards into the final rule that would allow fo r site-specific project desi gn, monitoring and closure. Additionally, the technology associated with large scale injection and storage of CO2 associated with el ectricity generation is st ill developing. EPA should
p rovide flexibility by designing the UIC pr ogram for GS of CO2 so the program requirements can evolve along with the te chnology over time rather than lock-in regulatory requirements that will likely become obsolete. Commenter Name: Chris M. Hobson Letter ID: 0201 Commenter Or g anization: Southern Compan y Comment ID: 22177

Commenter Name: Michael Stroben Letter ID: 0209 Commenter Or g anization: Duke Ener gy Comment ID: 22677RULE MUST PROVIDE FLEXIBILITY

The technologies described in the proposal will not likely be commercially deployed on a widespread basis for some ti me; therefore EPA’s rule must remain flexible in order to accommodate technologi cal developments rela ted to the GS of CO2 as they occur. It is also essentia l that performance-based standards be incorporated into the Final Rule to reflect the fact that the characteristics of GS sites will vary widely. The use of pe rformance-based standards rather than a one-size-fits-all approach will result in better pe rforming and more costeffective projects because they will have been tailored to a specific site’s characteristics.

Response: EPA believes that the Class VI requirements balance site-specific fl exibility with USDW
p rotection. Rather than setting performance or t echnology-based standards for GS projects, EPA is adopting a flexible approach, where operators of GS projec ts would develop and im plement site-specific
p lans for delineating the AoR, te sting and monitoring the site, pe rforming corrective action, and postinjection site care. EPA believes that the plans—wh ich would be reviewed a nd approved by the Director and periodically updated throughout th e life of the project—promot e an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a particular
p roject.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: captured using commercially available technologies. Due to its inherent carbon capture capability, gasification can serve a major role in Carbon Capture and Storage (CCS) projects. GTC’s interest in EPA’s proposed regulation derives from the importance of CCS to achieving future goals of CO2 emissions reduction while using secure and indigenous resources to meet our growing national need for chemicals, fertilizers, liquid fuels, hydrogen, and electricity.

EPA is commended for taking this action th at begins the process of providing regulatory clarity to a complex and importa nt topic. In its decision process, EPA needs to consider the importance of CCS to the success of the nation’s overall climate change, energy independenc e and economic growth strategies. Any rule for geologic storage of CO2 needs to provide an unambiguous framework that
p romotes the development and deployment of CCS while protecting the environment. Also, given the current state of expe rience in geologic sequestration, any
p rescription needs to be flexible and adaptive. In addition to regulatory clarity, climate change policy will be need ed to define a value for CO2 in order to drive deployment of CCS. After policy, cost will determine how quickly and widely CCS can be deployed. Currently, the value of CO2 is principally limited to its use in Enhanced Oil Recovery (EOR). The cost of CCS needs to be reduced by implementin g requirements that are necessar y and sufficient while not Commenter Name: Richard Guinn Letter ID: 0210 Commenter Or g anization: Eastman Chemical Compan y Comment ID: 22691compromising the protection of drinking water.

Response: EPA clarifies that the Class VI GS requirement s are designed to ensure that, where deployed, GS is conducted in a manner that protects USDWs from endangerment. The requirements apply to owners or operators of injection wells used to in ject CO2 for permanent storage, and do not apply to generators of CO2. Encouraging investment in CCS projects, addressing climate change, and setting a
p rice for carbon are outside the scope of the GS rulemaking.

See the remainder of EPA's responses to this comment and the final rule an d preamble for additional information on EPA's regulatory approach.

Comment: injection. SEPCo believes, as further de tailed in these comments that the
p roposed requirements should be stream lined significantly to increase the flexibility of the requirements for CO 2 injection and reduce the unnecessary regulatory burdens the proposed rule would impose. SEPCo respectfully recommends EPA modify its proposed regulatory approach accordingly.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Comment: use of GS as a technology for reducing CO2 emissions. In developing such regulations, it is important that EPA ma intain a flexible, performance-based approach that allows regulators to ta ilor specific permit requirements as appropriate based on the broad range of in jection sites and practices that may be encountered in the GS context and on the body of knowledge and experience that will be gained not only from pilot and demonstration projects, but from the initial deployment of commer cial scale GS projects.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project. Commenter Name: John Kin g Letter ID: 0211 Commenter Or g anization: Shell Exploration and Production Compan y (SEPCo) Comment ID: 22746

Commenter Name: John Kin g Letter ID: 0211 Commenter Or g anization: Shell Exploration and Production Compan y (SEPCo) Comment ID: 22757

Commenter Name: Paul L. Carpinone Letter ID: 0212Comment: It is imperative that the Final Rule re flect the challenges inherent in crafting regulations for commercial CO 2 injection activities when large-scale commercial operations are only at the nascent stage. The challenge confront ing EPA in this rulemaking is to establish a cost-effect ive and environmenta lly protective regulatory program to cove r a range of operations for which the technology will not be commercially deployed for a number of years. To meet this challenge, it is critical that the Final Rule emphasi ze performance-based rules that can be readily adjusted and fine-tuned as industr y and regulators alik e gain experience with large-scale CO2 sequestration. Tampa Electric acknowledges EPA's efforts to build flexibility mechanisms into the Proposal, including provisions for directorial discretion and the suggestion that forthc oming guidance may be used to clarify other requirements. In general, we agree that these methods will help create a regulatory framework that can e volve as information and technological advancements are gained in the field of carbon capture and sequestration. It is important, however, that a ny directorial discretion be clearly defined and limited; this can be achieved while still maintaining a rule that is flexible and avoids unnecessary prohi bitions. In addition, guidance on any aspect of the

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

EPA is developing guidances for States that descri be the process of applyi ng for and receiving primary enforcement authority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum federal criteria and requirements. The guidance will describe area s of Directorial discretion and considerations for how that discretion would be exercised. This guidance wi ll be available on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm.

Comment: Because information and t echnology related to carbon se questration will develop as industry and regulators gain experience with CCS, Tampa Electric urges EPA to avoid blanket prohibitions or arbitrary absolutes in the Final Rule. We agree that the appropriate standa rd underlying the technical requirements for CO2 GS wells is the protection of underground sources of drinking water (USDWs). However, because it is difficult to know at this point what methods or Commenter Or g anization: Tampa Electric Compan y Comment ID: 22898

Commenter Name: Paul L. Carpinone Letter ID: 0212 Commenter Or g anization: Tampa Electric Compan y Comment ID: 22900technology will be developed for inject ion and long-term storage of CO2 in a manner that is protective of USDWs -- and because there is sure to be demand for significant capacity for CO2 GS -- EPA should not prematurely preclude the use of specific types of sites or methods for Class VI CO2 injection. The Final Rule should leave the door open for a range of injection sites and methods (some of which are unknown or not yet fully unders tood), provided that the Owner or Operator can show that the injection and storage will be protective of USDWs.

Response: As described above, EPA believes that the Class VI requirements balance site-specific flexibility with USDW pr otection. EPA clarifies that the Class VI GS requirements are designed to ensure that, where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS projects and facilitating deploym ent are outside the scope of the GS rulemaking.

Comment: - Because the technology described in the Proposal will not be commercially deployed for a number of years, the Final Rule must be flexible enough to accommodate developments in information and technology related to carbon sequestration. Similarly, because there is li kely to be a significant amount of CO2 available for sequestration under the Program, the Final Rule should avoid arbitrary absolutes or blanket prohibitions regarding site selection or well construction or injection procedures. The Final Rule should keep available as many options as possible for site selection and method of in jection, subject always to the standard that any CO2 GS be protective of USDWs.

Response: As described above, EPA is us ing an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regulation, EPA plans, every six years, to collect and review
p roject data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

Other EPA Comment Codes and Descriptions: 3500 2.2.3 Area of Review Re evaluation (seeking comment); 5200 2.8.2 Post injection site ca re (seeking comment) (40 CFR 146.93) Comment: - Because carbon sequestration technol ogy is still developing and the characteristics and limitations of CO2 GS projects will vary greatly from one site to another it is essential to incorporate performance-based standards into the Final Rule, leading to a site-tailored approach to requirements for Area of Review ("AoR") reevaluation and post-inje ction site care and closure periods.

Response: The PISC requirements in the final GS ru le, as specified in §146.93(b), incorporate a combination of a fixed timeframe and a performance standard approach. EPA believes that a default PISC timeframe of 50 years, with Director's discretion to shorten or lengthen this timeframe, combined with a site-specific Director’s disc retion to create an alternative PISC time frame, ensures that USDWs are protected. The GS rule offers owners or operato rs flexibility regarding the duration of the PISC timeframe by: (1) allowing the Direct or discretion to shorten or lengt hen the PISC timeframe during the PISC period based on site-specific data, pursuan t to requirements at § 146.93(b); or (2) affordin g the Commenter Name: Paul L. Carpinone Letter ID: 0212 Commenter Or g anization: Tampa Electric Compan y Comment ID: 22905

Commenter Name: Paul L. Carpinone Letter ID: 0212 Commenter Or g anization: Tampa Electric Compan y Comment ID: 22906Director discretion to allow a Class VI well owner or operator to demonstrate, based on substantial data during the permitting process, that an alternative PI SC timeframe may be appropriate if it ensures nonendangerment of USDWs pursuant to requirements at §146.93(c). EPA expects that the Director will consider the types of information the commenter describes in determining whether the plume and
p ressure front no longer pose a risk of endangerment to USDWs and post- injection site care monitoring may be discontinued. EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts. EPA disagrees that the GS regulation should include performance-based standards for AoR calculation. However, EPA believes that consideration of site-specific conditions is appropriate for the AoR calculation and reevaluation process. EPA believes th at the flexibility incorporated into the AoR and corrective action plans and the provision for AoR re evaluation as required at §146.84(e) provide for an ongoing review of the site and a dial ogue between the Director and the ow ner or operator to ensure that the most appropriate m odeling and corrective acti on technologies are used to protect USDWs from endangerment. However, EPA believes that setting a minimum reevaluation fre quency is appropriate. In the final rule, the Agency changed the minimum fr equency for the AoR reevaluation at §146.84(e) from 10 years to at least every 5 years in the final GS rule . EPA believes that this revised frequency addresses commenters' concerns about the inherent uncertainties in modeling CO2 movement, the emerging nature of GS technology, risk-based targeting of monitoring activities, and the unique nature of CO2 GS.

Comment: - While directorial discretion is a useful mechanism to ensure flexibility in the Final Rule, such discretion must be clearly defined and limited.

Response: EPA is developing guidances fo r States that describe the process of appl ying for and receiving primary enforcement au thority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum fede ral criteria and requirements. The guidan ce will describe ar eas of Directorial discretion and considerations for how that discretion would be exercise d. This guidance will be available on EPA’s website at http://w ater.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) Comment: Many statements in this section of the pr oposed rule specify exactly what types of data will be collected and how th ey will be presen ted in a permit application. Across the United States, there are widely varying geologies, available regional data sets , and how well various technologies perform. The
p ermitting authority for a state or re gion should have the flexibility to determine what types of information an operator should present to adequately characterize a specific in jection well site. Commenter Name: Paul L. Carpinone Letter ID: 0212 Commenter Or g anization: Tampa Electric Company Comment ID: 22911

Commenter Name: Dennis R. James Letter ID: 0214 Commenter Or g anization: North American Coal Corporation (NAC) Comment ID: 22963For example, the following statement is made: "Today’s propos al would require owners or operators to submit geochemi cal data on (a) the injection zone, (b) the confining zones, (c) containment zone s above the confining zones in which any potentially migrating CO2 could be tr apped, (d) all USDWs, and (e) any other geologic zone or formation that is important to the proposed monitoring
p rogram." This essentially requires an operator to collect geochemical data on the entire geologic column: From the su rface down to the target formation. It is important to geochemically define the target formation and its overlying seal. It is also prudent to obtain data from adjacent formations that may be involved if leakage occurs. However, does this data all the way to the surface in any way add additi onal USDW protection? The perm itting authority should have some discretion to limit the required data, based on the geology of the area.

Response: The Agency believes that the requirement at §146.82(a)(6) to submit baseline geochemical data on subsurface geologic formati ons, including all USDWs in the Ao R is appropriate and protective of USDWs. EPA believes that this data will support monitoring plan development, inform injectate fate and transport model development (e.g., by providing appropriate input parameters), and provide information needed to respond to any unexpected a nd unpermitted leaks outside of the injection zone. The baseline geochemical informat ion will allow the owner or opera tor and permitting authority to evaluate monitoring data and identify any changes in subsurface geochemistry that may indicate fluid
movement.

The rule requires geochemical analysis of, at a minimum, the injection zone, confining zone, and all USDWs (§146.82(a)(6)). These geochemical tests are necessary to ensure the adequacy of the confining system and to serve as a baseline for future m onitoring. The Director has the discretion to require geochemical analysis of additional subsurface zones if in the Director 's opinion they are necessary for the protection of USDWs from endangerment.

EPA agrees that site characterization should be site-specific, particularly in light of the variety of geologic settings in which GS ma y be employed. EPA believes that, while there is a large amount of required information, the owner or operator is given flexibility in determining what methods are used to demonstrate the suitability of a potential site. EP A envisions an ongoing dialogue between the Director and the owner or operator during the permitting proces s (as well as throughout th e operation of the site).

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators and Directors in evaluating permit requirements and applications under §146.82. The guidance provides recommendations regarding charac terizing the regional geology and hydr ogeology of a proposed GS site as well as performing the necessary geochemical, geomechanical, and geophys ical analyses of the injection and confining zone. The guida nce can be found on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Comment: A. Tri-State acknowledges EPA's efforts to use a "performance-based" approach and to build flexibility mechanisms into the rule. In general, Tri-State agrees that these methods will help create a re gulatory framework that can evolve as information and technologica l advancements are gained in the field of carbon capture and sequestration. It is import ant, however, that any directorial discretion be clearl y defined and limited; this can be achieved while still Commenter Name: Barbara Walz Letter ID: 0216 Commenter Or g anization: Tri-State Generation and Transmission Association, Inc. Comment ID: 22965maintaining a rule that is flexible and avoids unnecessary prohibitions. In

Response: EPA is developing guidances fo r States that describe the process of appl ying for and receiving primary enforcement au thority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum fede ral criteria and requirements. The guidan ce will describe ar eas of Directorial discretion and considerations for how that discretion would be exercise d. This guidance will be available on EPA’s website at http://w ater.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Comment: We also learned, however, that there ar e number of critical policy, legal, and technical issues that must be resolved before geologic storage can be implemented on a full-scale commercial basis. The proposed rule is a significant early step in helping to resolve thes e issues. The rule, however, must be designed to facilitate, not unduly hinde r, progress towards commercial deployment of geologic storage. Large-s cale underground injection and storage of CO2 remains an emerging technology and it is important that any rule adopted by EPA be flexible enough to adapt to advances in science and technology moving forward. We offer these comments in s upport of a flexible and appropriately tailored rule that will facilitate ge ologic storage technology and projects while protecting underground sources of drinking water.

Response: EPA clarifies that the Class VI GS requirement s are designed to ensure that, where deployed, GS is conducted in a manner that protects USDWs fr om endangerment. Encouraging investment in CCS
p rojects and facilitating de ployment are outside the scope of the GS rulemaking.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: Default Provisions

Although underground injection of CO2 is well established for enhanced oil and gas recovery, it remains in it nascent stages with respect to large-scale geologic storage. Throughout the proposed rule, EPA suggests the need for blanket prohibitions, limitations and default provisions that are overly conservative and not supported by establis hed facts. Such examples include:

- 50-year default post closure period - Mandatory 10-year reevaluation of the Area of Review (AoR) - Categorical exclusion of specific formations (e.g,. coal seams) - Prohibitions on types of well drilling (e.g., horizontal, angled) - Mandate to alwa y s in j ect below the lowermost USDW Commenter Name: Olon Plun k Letter ID: 0217 Commenter Or g anization: Xcel Ener gy , Inc. Comment ID: 21550

Commenter Name: Olon Plun k Letter ID: 0217 Commenter Or g anization: Xcel Energy, Inc. Comment ID: 21553- Prohibition on use of exempt aquifers - Prohibition on hydraulic fracturing - Mandatory use of tracers - Mandatory annual and electronic reporting

At this early stage, EPA should avoi d establishing arbitr ary limits or
p rohibitions that might stifle research and development, or that are so excessively conservative as to close th e door on geologic storage projects that are otherwise safe and economically sound. The final rule must recognize that the potential risks, as well as the appr oaches to mitigate or eliminate that risk, will vary greatly from project to project. The broad imposition of administrative and technical requirements designed to be protective of the highest risk projects unnecessarily burden lo w to moderate risk projects. Viable
p rojects might not be proposed or move fo rward due to excessive economic burdens or regulatory uncertainty. EPA should avoid a "one size fits al l" approach and instead develop a framework that provides the flexibilit y for projects to be successfully permitted, based on each project's unique characteristics and circumstances.

Long-Term Liability

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Comment: Just as in nature with deep-sourced, natu ral CO2, there are low-risk sites that will permanently entrap CO2, and there ar e places where it may migrate, perhaps even to the surface. CO2 is a naturally o ccurring substance, and movement within the subsurface is very common. Rather than trying to fashion rules that protect against surface escape in all subsurface co nditions, regulatory oversight needs to recognize the nearly ubi quitous presence of the molecule while identifying low-risk sites for entrapment and pr ovide flexibility in regulation to accommodate the attendant risk level.

In order to achieve statistically si gnificant reductions of greenhouse gas emissions, large-scale carbon capture and storage (CCS) will have to be implemented at numerous sites. One of the greatest potenti al barriers to widespread deplo y ment of sequestration pro j ects would be the specification of Commenter Name: Edward Steadman Letter ID: 0220 Commenter Or g anization: The Energy and Environmenta l Research Center at the University of North Dakota Comment ID: 21573overly complex well design and monitoring of sites. Experience shows that exotic well designs add little benefit, whil e, on the other hand, judicious site selection adds greatly to the security of emplacement. For example, subsurface sequestration formations overlain by bedded salts provide optimal conditions for long-term storage. The focus of regulation should be performance criteria, not design criteria. As long as CO2 sequestration sites ca n meet the standards required for permitting, inj ection of CO2 for sequestration is, to a large extent, similar to EOR operations. In tu rn, requirements for injection wells accessing judiciously selected zones for sequestration should be more closely aligned with those of Class II standa rds than the more stringent Class I hazardous waste well standards. As curr ently proposed, the Class VI requirements are more reflective of Class I h azardous waste well standards.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Comment: Detailed Comments

Page 43492. SUMMARY. Regarding the phrase "...help ensure consistency..."

Consistency does not necessarily mean th at regulations are appropriate or effective. Geology is notoriously heterogeneous and, therefore, by definition inconsistent. Striving for c onsistency across geologic systems is difficult at best. One need only to look at the hi story of injection regulation across different states to see a la ck of consistency is appr opriate and primarily due to heterogeneity and inconsistency with respect to regional geologic characteristics. Guidelines must be flex ible. Flexibility to ensure the safe maximization of CO2 storage must not be compromised by a desire to ensure consistency of rules across all geologic settings.

Response: EPA agrees that permitting deci sions for GS wells should be ba sed on site-specific factors. The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable fo r GS. Additionally, many of the permit requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testing and monitoring, and injec tion well plugging and post- injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Dir ectorial discretion and considerations for how that discretion would Commenter Name: Edward Steadman Letter ID: 0220 Commenter Or g anization: The Energy and Environmenta l Research Center at the University of North Dakota Comment ID: 21577b e exercised. The Agency believes th is balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each project, while providing consistency in permitting across the U.S.

As described above, encouraging investment in CCS projects and facilitating de ployment are outside the scope of the GS rulemaking.

Comment: Page 43496. B. What Is EPA’s Authority unde r the Safe Drinking Water Act (SDWA) to Regulate Injecti on of CO2?Regarding the following quote from the document, referring to a key aspect of the Safe Drinking Water Act:

"Section 1421 (b)(3)(A) of the Act also provides that EPA’s UIC regulations shall permit or provide fo r consideration of varying, geologic, hydrological, or historical conditions in di fferent States and in di fferent areas within a State."

It is important that this aspect of the SDWA is a guiding principle for the
p roposed regulations. Based on those words in the SDWA, flexibility is demanded by statute and must be built into a ny UIC regulations. Unfortunately, the regulations proposed for GS wells in this document are often anything but flexible, but rather are quite prescriptive and inflexible.

Response: As described above, EPA believes that the Class VI requirements balance site-specific flexibility with USDW prot ection. The final GS rule affords flexib ility to owners or operators. Many of the permit requirements will be established th rough site-specific plans de veloped by the owner or operator and approved by the Director.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: There is also text in this section th at can be interpreted as requiring the owner/operator to submit core, outcrop, seismic surve y, cross sections, well logs, and other unspecified data. Some later passages on this subject suggest that they are not all necessarily required, but rather are examples of types of data that could be used to demonstrate and quantify various key characteristics of a formation. With respect to the need for various types of geological data, the document is at times vague, inc onsistent and, occasionally, even contradictory. It is crit ical that geologic heterogeneity and regional differences in data availability be acknow ledged and state or regional directors be given the flexibility to make decisions based on data sets that reflect the geologic and regional differences. For instan ce, seismic survey data are limited in coverage, are expensive to acquire, can be inconclusive with respect to interpretation, and should not be unive rsally required as a precondition for site consideration. The re g ulations must be performance- b ased and reinforce the Commenter Name: Edward Steadman Letter ID: 0220 Commenter Or g anization: The Energy and Environmenta l Research Center at the University of North Dakota Comment ID: 21585

Commenter Name: Edward Steadman Letter ID: 0220 Commenter Or g anization: The Energy and Environmenta l Research Center at the Universit y of North Dakota Comment ID: 21611need to technically and effi ciently achieve specific goals, such as proving that an adequate and competent seal exists or that a target formation has sufficient injectivity. The regulations should not pr escribe precisely how such proof is obtained, but should only dictate that sufficient proof be presented to the director. The regulations should give th e director a significant degree of flexibility to determine whether the body of evidence presented by the owner/operator constitutes sufficient proof that USDWs will be protected. The regulations may include a list of useful data types, but EPA should clearly state that the list is one of available tools from which to choose the most applicable to a specific si te, not a list of required a pplications and data that must be acquired and presented.

Response: EPA disagrees that any of these protective requirements are unnecessary. EPA believes that requiring appropriate site charact erization by the owner or opera tor (under §146.82) and providing an appropriate degree of flexibility to the Director to evalua te site-specific geologic data will afford the greatest protection of USDWs from e ndangerment. EPA believes that it is important for the Director to have as much site-specific inform ation as possible in order to make an informed decision to permit injection for GS at a specific site. The GS regulation allows flexibility wh ere appropriate. Certain requirements (e.g., the need to characterize additional confining layers) are at the Director's discretion (§146.83(b)), based on his or her unde rstanding of a particular site.

Additionally, EPA disagrees that consideration of local and regional seismicity is not important. The site characterization provisions in the GS rule, includi ng a review of the local and regional geology, and detailed review of any known or poten tial seismically active terrain in th e vicinity of a proposed GS site are necessary to minimize the potential for induced se ismic events or the reac tivation of faults, which are a known potential risk associated with inject ion and are addressed in all aspects of the UIC regulations.

Other EPA Comment Codes and Descriptions: 3140 2.1.4 Comments that the proposed geologic data requirements are too stringent Comment: Following is a series of comments with regard to the quote on page 43505: "...require owners or operators to submit geochemical data on (a) the injection zone, (b) the confining zones, (c) contai nment zones above the confining zones in which any potentially mi grating CO2 could be trapped, (d) all USDWs, and (e) any other geologic zone or formation that is important to the proposed monitoring program."

The EPA should recognize that it is e ssentially saying that the entire rock column from the injection zone to the surface must be geochemically characterized. Such charac terization goes far above and beyond that which is necessary to protect the USDWs. It is e ssentially forcing owne rs/operators to
p ay for potentially unnecessary research activities. For instance, in the Williston Basin, a vast majority of th e hydrocarbon production is historically from Paleozoic formations. One result of this is that there is a wealth of readily available data on the nature of Paleozoic formations in the Williston Basin. Likewise, the Cenozoic formations ar e fairly well characterized because of the presence of coal and potable aqui fers. However, the Mesozoic formations Commenter Name: Edward Steadman Letter ID: 0220 Commenter Or g anization: The Energy and Environmenta l Research Center at the University of North Dakota Comment ID: 21612that lie between those two groups are relatively poorly understood. This is because there is little economic incentive to characterize most of the Mesozoic rocks beyond the fact that they are dominated by low permeability shales and evaporites. There are 15 named rock units in the Mesozoic section of the Williston Basin. The regulations as propos ed indicate that they must all be geochemically characterized. To geochemically characteri ze all of these Mesozoic units as part of a GS project in which the primary sinks and seals are in the deeper Paleozoic would be very expensive and of dubious value to anyone. Once again, there must be flexibility and di scretionary powers given to directors with respect to what formations must be geochemically char acterized. Indeed, this concept of flexibility must apply for all types of char acterization that are considered necessary to prove that a GS well applicati on can be approved.

Response: The Agency believes that the requirement at §146.82(a)(6) to submit baseline geochemical data on subsurface geologic formati ons, including all USDWs in the Ao R is appropriate and protective of USDWs. EPA believes that this data will support monitoring plan development, inform injectate fate and transport model development (e.g., by providing appropriate input parameters), and provide information needed to respond to any unexpected a nd unpermitted leaks outside of the injection zone. The baseline geochemical informat ion will allow the owner or opera tor and permitting authority to evaluate monitoring data and identify any changes in subsurface geochemistry that may indicate fluid
movement.

The rule requires geochemical analysis of, at a minimum, the injection zone, confining zone, and all USDWs (§146.82(a)(6)). These geochemical tests are necessary to ensure the adequacy of the confining system and to serve as a baseline for future m onitoring. The Director has the discretion to require geochemical analysis of additional subsurface zones if in the Director 's opinion they are necessary for the protection of USDWs from endangerment.

EPA agrees that site characterization should be site-specific, particularly in light of the variety of geologic settings in which GS ma y be employed. EPA believes that, while there is a large amount of required information, the owner or operator is given flexibility in determining what methods are used to demonstrate the suitability of a potential site. EP A envisions an ongoing dialogue between the Director and the owner or operator during the permitting proces s (as well as throughout th e operation of the site).

Comment: In the context of geologic sequestration of CO2, it is imperative to maintain flexibility in the regulatory requirements due to the site-specific nature of this activity and beca use the technology is continually advancing. For geologic sequestration of CO2, "one-size-fits-all" is not an approach that is necessarily or reasonably protective of USDWs. Rather, each site has sitespecific characteristics that merit diff ering requirements. Indeed, what may appear to be a standard protective measur e in the context of a particular site could actually have the opposite effect a nd increase potential risks at another site. (See A Technical Basis for Carbon Di oxide Storage, CO2 Capture Project, December 2008.)

Consequently, HEI strongly encourages EP A to provide performance standards for the various phases of a geologic sequestration project (i.e., site characterization, operation and si te closure), while providin g the Director Commenter Name: Tiffany Rau Letter ID: 0224 Commenter Or g anization: H y dro g en Ener gy International Comment ID: 21648flexibility to add requirements as necessary to address site-specific characteristics. This type of approach, consistent wi th Regulatory Alternative 2, offers the degree of flexibility that the permitti ng authority will require to tailor fit-for-purpose requirement s that address site specific characteristics. Furthermore, it ensures th at project costs will be commensurate with the geologic risk, and will further the continued evolution of the best technologies.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: With respect to monitoring requirements in general, EPA should adopt regulations that are performance and risk-based and will result in a site-specific monitoring program that is designed to understand the location, movement and stabilization of the CO2 plume in the subsurface as well as the early identification of any leakage for appropr iate corrective action. HEI commends EPA for its efforts in this regard, but believes that further modification is necessary. HEI agrees with the proposal to allow a phased approach to conduct

Response: EPA agrees with commenters and believes that flexibility is important in developing and implementing a monitoring plan that is appropriately tailored for a sp ecific GS site. The purpose of the requirement at §146.90 to develop site -specific testing and monitoring plans is to ensure that the monitoring performed at a site is appropriate for site operational conditions and the geologic setting. EPA believes that this is the best approach for a ddressing potential risks at GS sites. These flexible
p rovisions in the monitoring requirements for Class VI wells enable the owner or operator to tailor monitoring programs to the specific needs of eac h project in consultati on with the Director.

The final regulation provides for flexibility in: 1) met hodologies used to collect these data, 2) the spatial resolution at which the data should be collected, a nd 3) how often the data should be collected. The number and placement of monitoring wells will be based on site-sp ecific information such as the calculated AoR, injection rate and volume, site geology, baseline data, and the presence of artificial
p enetrations within the AoR. In some instances, ther e may be a limited number of options for complying with EPA's minimum requirements. For example, monitorin g for g eochemical chan g es will require use Commenter Name: Tiffany Rau Letter ID: 0224 Commenter Or g anization: H y dro g en Ener gy International Comment ID: 21676of monitoring wells and collection of groundwater samples for chemical analysis. Many options currently exist for complying with other requirement s, such as tracking the position of the plume and
p ressure front within the injection zone.

Flexibility is also provided regarding how to monito r for the specific data required by the final rule. The testing and monitoring plan is developed by the owner or operator in consultati on with the Director and is designed to ensure that a detailed, Director -approved document describing how monitoring will be conducted during the lifetime of the project exists. EPA is de veloping guidance on testing and monitoring to assist owners or operators and Directors in evaluating requirements under §146.90, including proposed monitoring plans. The guidance describes availabl e technologies and recommended approaches for implementing a testing and monitoring plan, in cluding pre-operational geophysical logging and testing of injection we lls, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm.

Comment: In the context of geologic sequestration of CO2, it is imperative to maintain flexibility in the regulatory requirements due to the site-specific nature of this activity and because the technology is continuall y advancing. For geologic sequestration of CO2, "one-size- fits-all" is not an approach that is necessarily or reasonably protective of USDWs. Rather, each site has site-specific characteristics that merit di ffering requirements. Indeed, what may appear to be a standard protective measure in the contex t of a particular site could actually have the opposite effect and increase potential risk s at another site. (See A Technical Basis for Carbon Di oxide Storage, CO2 Capture Project, December 2008.)

Consequently, BP strongly encourages EPA to provide performance standards for the various phases of a geologic sequestration project (i.e., site characterization, operation a nd site closure), while providing the Director flexibility to add requirements as ne cessary to address site-specific characteristics. This type of approach, consistent wi th Regulatory Alternative 2, offers the degree of flexibility that the permitti ng authority will require to tailor fit-for-purpose requirement s that address site specific characteristics. Furthermore, it ensu res that project costs will be commensurate with the geologic risk, and will further the continued evolution of the best technologies.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is usin g an adaptive approach to re g ulatin g GS under the UIC Pro g ram. Even after Commenter Name: Brian Williams Letter ID: 0225 Commenter Or g anization: BP Alternative Ener gy North America, Inc. (BP) Comment ID: 21713finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Other EPA Comment Codes and Descriptions: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 CFR 146.90) Comment: With respect to monitoring requirements in general, EPA should adopt regulations that are performance and risk-based and will result in a site-specific monitoring program that is designed to understand the location, movement and stabilization of the CO2 plume in the subsurface as well as the early identification of any leakage for appropr iate corrective action. BP commends EPA for its efforts in this regard, but believes that further modification is necessary. BP agrees with the proposal to allow a phased approach to conduct

Response: EPA agrees with commenters and believes that flexibility is important in developing and implementing a monitoring plan that is appropriately tailored for a sp ecific GS site. The purpose of the requirement at §146.90 to develop site -specific testing and monitoring plans is to ensure that the monitoring performed at a site is appropriate for site operational conditions and the geologic setting. EPA believes that this is the best approach for a ddressing potential risks at GS sites. These flexible
p rovisions in the monitoring requirements for Class VI wells enable the owner or operator to tailor monitoring programs to the specific needs of eac h project in consultati on with the Director.

The final regulation provides for flexibility in: 1) met hodologies used to collect these data, 2) the spatial resolution at which the data should be collected, a nd 3) how often the data should be collected. The number and placement of monitoring wells will be based on site-sp ecific information such as the calculated AoR, injection rate and volume, site geology, baseline data, and the presence of artificial
p enetrations within the AoR. In some instances, ther e may be a limited number of options for complying with EPA's minimum requirements. For example, monitoring for geochemical ch anges will require use of monitoring wells and collection of groundwater samples for chemical analysis. Many options currently exist for complying with other requirement s, such as tracking the position of the plume and
p ressure front within the injection zone.

Flexibility is also provided regarding how to monito r for the specific data required by the final rule. The testing and monitoring plan is developed by the owner or operator in consultati on with the Director and is designed to ensure that a detailed, Director -approved document describing how monitoring will be conducted during the lifetime of the project exists. EPA is de veloping guidance on testing and monitoring to assist owners or operators and Directors in evaluating requirements under §146.90, including proposed monitoring plans. The guidance describes availabl e technologies and recommended approaches for implementing a testing and monitoring plan, in cluding pre-operational geophysical logging and testing of injection we lls, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm. Commenter Name: Brian Williams Letter ID: 0225 Commenter Or g anization: BP Alternative Ener gy North America, Inc. (BP) Comment ID: 21721

Commenter Name: Brian Williams Letter ID: 0225 Commenter Or g anization: BP Alternative Ener gy North America, Inc. (BP) Comment ID: 21729Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Furthermore, in various parts of the Proposed Rule, EPA has prescribed
p articular monitoring technologies. Mandating any spec ific technology(ies) would have the adverse effect of (1) promot ing particular technologies to the exclusion of other developed - and to be developed - technology(ies), and (2) substantially increasing costs without necessarily contributing to the
p rotection of USDWs. This would hinder th e development and deployment of CCS at commercial scale. Moreover, it would discourage the development of other technologies. BP therefore strongly discourages EPA from promulgating regulations that mandate the use of any specific monitoring technology.

Response: EPA agrees that prescribing spec ific technologies to be used in all cases for GS would not be appropriate given the variability in sites, and believes that the rule provides flexibility to owners or operators to develop site-specific testing and m onitoring plans that employ appropriate technologies
p rovided they meet the requirements at §146.90. EPA is developing guidance on te sting and monitoring to assist owners or operato rs and Directors in evaluati ng requirements under §146.90, including
p roposed monitoring plans. The guidance descri bes available technologi es and recommended approaches for implementing a testing and monitoring plan, in cluding pre-operational geophysical logging and testing of injection we lls, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/t ype/groundwater/uic/wells_sequestra tion.cfm. In addition, in January 2009, DOE published a best practices manual entitl ed "Monitoring, Verification, and Accounting of CO2 Stored in Deep Geologic Formations" (DOE/NETL-311/081508); this manual is included in the docket for the for the final GS rule.

Other EPA Comment Codes and Descriptions: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) Comment: Plume and Pressure Front Monitoring

EPA would require each Class VI well permit application to contain a monitoring
p lan to verify that a GS well is opera ting as intended and not endangering USDW. EPA should be aware that certain m onitoring technology is currently under development and not available as a tool in the near term to meet the proposed EPA requirements. Further, the usefulness of available tec hnology is a function of site-specific characterizations. The EPA should not impose a one-size-fitsall approach. CURC recommends that the EP A permit well owners and operators to
p ropose the use of available technology to meet the proposed requirements and then to amend their tailored moni toring plans as technology evolves.

Response: EPA agrees that prescribing spec ific technologies to be used in all cases for GS would not be appropriate given the variability in sites, and believes that the rule provides flexibility to owners or operators to develop site-specific testing and m onitoring plans that employ appropriate technologies
p rovided they meet the requirements at §146.90. EPA is developing guidance on te sting and monitoring to assist owners or operato rs and Directors in evaluati ng requirements under §146.90, including
p roposed monitoring plans. The guidance descri bes available technologi es and recommended approaches for implementin g a testin g and monitorin g plan, includin g pre-operational g eoph y sical Commenter Name: Ben Yama g ata Letter ID: 0227 Commenter Or g anization: Coal Utilization Research Council Comment ID: 21789logging and testing of injection we lls, MITs, injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s website at http://water.epa.gov/t ype/groundwater/uic/wells_sequestra tion.cfm. In addition, in January 2009, DOE published a best practices manual entitl ed "Monitoring, Verification, and Accounting of CO2 Stored in Deep Geologic Formations" (DOE/NETL-311/081508); this manual is included in the docket for the for the final GS rule.

Comment: C. The Regulatory Design

Section III.A. of the Preamble presents several approaches for how the UIC rules for CO2 injection might be structured. EP A selected an approach described as "Tailored Requirements," based on the perceived ability of that approach to be "tailored" to the volume, buoyancy, and corr osiveness of CO2 from specific CCS operations. It rejected a more flexible alternative, described as "General Requirements," because it wa s not "tailored." A performance-based program with requirements that prescribe the require d outcomes of properly designing and operating a CCS project, rather than a pr ogram that prescribes how to achieve those outcomes, is preferable. A performa nce-based approach better accommodates changes in knowledge and technology over time, and would allow implementing state permitting authorities the flexibilit y to use their expertise to address varying geologic and geographic situati ons. In many instances, retaining the
p rimacy of state regulatory authority may better address such an approach, and in all instances a performa nce-based approach would provide federal or state authorities and the CCS operators the flexibility to achieve required outcomes.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

In response to the comment that States with primacy be able to develop “performance-based standards,” the Agency clarifies that States, Tribes, and Terr itories can develop require ments for Class VI and submit primacy applications (under Section 1422 of the SDWA) for review and approval by EPA as long as the requirements are as stringent as or more stringent th an the Federal minimum requirements.

Comment: regulatory certainty for early CCS projec ts. EPA should acknowledge that overly
p rescriptive regulations can discourage t echnological development and commercial deployment. Such an outcome can adversel y impact the environment by impairing the design or implementation of a CO2 mitigation program and can also lead to costl y and unnecessar y requirements. We also encoura g e EPA to reconsider the Commenter Name: Ben Yama g ata Letter ID: 0227 Commenter Or g anization: Coal Utilization Research Council Comment ID: 21793

Commenter Name: Ben Yama g ata Letter ID: 0227 Commenter Or g anization: Coal Utilization Research Council Comment ID: 21800b asic design of the UIC Class VI program and create a more flexible performancebased program given the fact that CO2 in jections has been conducted safely in the U.S. for more than a decade, rather than the more prescriptive program
p roposed. Lastly, CURC recommends that EPA issue guidance for an interim Class

Response: As described above, EPA believes that the Class VI requirements balance site-specific flexibility with USDW prot ection. EPA adds that it is using an ad aptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether th e appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

Comment: Complexity and Consistency of Regulations - We recognize that EPA has attempted to provide a great deal of flexibility in most aspects of the regulations, while incorporating most of currently known c oncepts and technologies in permitting, operation, and monitoring of the sites. The flexibility has primarily been incorporated through making the requireme nts subject to "directors" decision. Our concern is that some directors may choose to re quire all of the numerous requirements mentioned in the permit, ra ther then selectively requiring an appropriate portfolio of safeguards. Such an approach could deter operators from considering the GS as an option for CO2 mitigation. A nother concern is that the requirements will be applied with inconsistent level of flexibility in various regions and states, making some re gions more or less favorable for GS. We encourage EPA’s continuing oversight and guidance in ensuring that the regulations are applied c onsistently and with a reasonable selection of requirements.

Response: EPA is developing guidances fo r States that describe the process of appl ying for and receiving primary enforcement au thority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum fede ral criteria and requirements. The guidan ce will describe ar eas of Directorial discretion and considerations for how that discretion would be exercise d. This guidance will be available on EPA’s website at http://w ater.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Comment: 7. The Proposed Rule precludes a me aningful role for States.

UIC regulations developed by EPA must permit or provide consideration of varying geologic, hydrological, or historical conditions in di fferent States and in different areas within a State. The Proposed Rule does not allow State directors to use their expertise a nd knowledge to account for these varying conditions.

Response: EPA agrees that permitting deci sions for GS wells should be ba sed on site-specific factors. The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable for GS. Additionall y , man y of the permit Commenter Name: Neera j Gupt a Letter ID: 0229 Commenter Or g anization: Battelle Ener gy Technolo gy (BET) Comment ID: 21813

Commenter Name: A. James Ma y e r Letter ID: 0230 Commenter Or g anization: A. J. Mayer International on behalf of the American Ener gy Securit y Initiative Comment ID: 21884requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testing and monitoring, and injec tion well plugging and post- injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Dir ectorial discretion and considerations for how that discretion would be exercised. The Agency believes th is balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each project, while providing consistency in permitting across the U.S.

In response to the comment that States with primacy be able to develop “performance-based standards,” the Agency clarifies that States, Tribes, and Terr itories can develop require ments for Class VI and submit primacy applications (under Section 1422 of the SDWA) for review and approval by EPA as long as the requirements are as stringent as or more stringent th an the Federal minimum requirements.

Other EPA Comment Codes and Descriptions: 2000 1.5 Need for a New Cla ss of Injection Well Comment: 3. EPA should begin with a Class II injecti on well framework to assure that the rules are flexible enough to consider site-specific characteristics and knowledge gained from the extensive CO2 history and the ongoing demonstration and pilot projects.

Response: EPA agrees that owners and operators of Class II wells have experience that will be helpful in implementing the Class VI requirements, but EPA disagrees that the risks posed by long-term storage of CO2 for GS can be addressed under existing UIC requi rements, such as those for Class II wells. EPA believes that there are significant differences between how projects ar e operated, as well as the risks
p osed by these different injection activities. The new tailored approach of the GS rule was designed to address the general risks deep inje ction may pose to USDWs and was tail ored specifically to address the risks posed by long-term storage of CO2 (i.e., very large volumes, very long time-periods, and reservoir
p ressure conditions).

The final Class VI regulations require that any owner or operator injecting CO2 for the primary purpose of long term storage obtain a Class VI permit with some special consideration for the fact that they are transitioning from a well not originally designed to meet Class VI requirements. The Director has the authority to determine at what point a Class VI perm it is required for those pr ojects that are transitioning from the primary purpose of EOR to long term storage of CO2. The fi nal regulation pr ovides a set of technical factors for the Director to evaluate in making this determin ation, at §144.19. EP A believes that this approach provides suff icient protection of USDWs when there is an increased risk to USDWs as compared to traditional Class II operations while allowing for site -specific flexibility. For more information, please see the di scussion on transition of Class II wells in the preamble to the final GS rule.

Furthermore, EPA agrees that flex ibility is important fo r regulating GS activit ies. EPA has taken a regulatory approach which promotes USDW protection, incorporates flexibility or the discretion of the
p ermitting authority when appropriate, seeks to li mit burden on owners or operators and permitting agencies, and provides a foundation for national consistency in permitting of GS projects. For example, under the final rule, many of the pe rmit requirements must be establ ished through site -specific plans (e.g., AOR and corrective action pla n, testing and monitoring plan, et c.) developed by the owner or operator and approved by the Director. Consequently EP A expects that owners or operators will consult with the Director as they develop, implement, and update these plans. Additiona lly, the Director has the discretion to approve alternatives to the requirements in some cases. For example, the Director ma y in Commenter Name: A. James Ma y e r Letter ID: 0230 Commenter Or g anization: A. J. Mayer International on behalf of the American Ener gy Securit y Initiative Comment ID: 21886certain situations modify the length of the post-inject ion site care period or a pprove an alternative postinjection site care timeframe as part of the permitting proces s under §146.93, allow the use of alternate methods for mechanical integrity testing under §146.89, or grant waivers from the requirement to inject below the lowermost USDW under §146.95.

Other EPA Comment Codes and Descriptions: 1410 1.2.1 Comments in support of EPA/rulemaking; 1850 1.4.2 CO2 GS Field Research Comment: Montana-Dakota strongly suppor ts research and developm ent efforts underway to facilitate commercial-scale CO2 capture and sequestration (CCS) projects, and shows this support specifically through its active membership in the Plains CO2 Regional (PCOR) Partnership. Led by the EERC and assisted by its members, PCOR and has developed and is currently carr ying out two CO2 geologic sequestration
p rojects designed to demonstrate th e effectiveness of CO2 geologic sequestration. As these efforts increase, it is necessary to develop clear, flexible and appropriately tailored regulat ions to facilitate the development of and spur investment in carbon capture and sequestration technology. The proposed rule assists with creating additional ce rtainty in approaching GS project development, however there are some concerns that need to be addressed. MontanaResponse: EPA acknowledges the value of the DOE pilot pr ojects and resultant data and information generated by such projects. EPA has evaluated perm its and reviewed operationa l data and information associated with the seven RCSPs funded by the U.S. Department of Energy and coordinated through the N ational Energy Technology Laboratory (N ETL). In addition to the inform ation cited in the preamble to the proposed rule, EPA published a No tice of Data Availability and Request for Comment on August 31, 2009 (74 FR 44802) in which the Agency described the results of research at three DOE partnership sites: the Escatawpa, Mississippi project; the Aneth Field project in Paradox Basin, Southeast Utah; and the Pump Canyon Site, New Mexico.

EPA agrees that flexibility to a ddress new research is important. Ev en after finalizing the rule, the Agency plans to collect and review data every six years on GS projects, in cluding research by the DOE Partnerships, to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

EPA agrees that the implem entation of the GS rule in a manner that ensures protection of USDWs from endangerment is important to esta blishing a foundation for further adva nces in the field of CO2 GS. EPA acknowledges the need for regulatory certainty: the final GS requirements provide a level of certainty by setting forth unique requirements for GS. These require ments include: the tailored AoR delineation process at §146.84, the types of monito ring appropriate to GS projects (§146.90) and the
p ost-injection site care process (§146.93). For additiona l information on these requirements, please also see the discussion of EPA’s Final Regulatory Appr oach in the preamble to the final GS rule.

EPA agrees that an adaptive and flexible ap proach is appropriate. To protect USDWs from endangerment and meet the potentially fast pace of GS deployment, EPA is using an adaptive approach to regulating CO2 inje ction for GS. The Agency plans to collect and review data every six years on GS
p rojects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate

or necessar y . An adaptive approach will allow re g ulator y development to proceed in time to meet the Commenter Name: Abbie Krebsbach Letter ID: 0235 Commenter Or g anization: Montana-Dakota Utilities Co. Comment ID: 23177current and future demands for Class VI permits while EPA continues to gather data from pilot projects and other research as it becomes available.

Comment: Utilize Performance-based St andards for Proposed Sites

As proposed, EPA's regulations contain a num ber of default provisions that would apply universally to projects. Rather than imposing default provisions, those
p ortions of the rulemaking that address i nherently site-specific issues should allow for site-specific, performance-ba sed determinations as part of the
p ermitting process. Sites will differ greatly geol ogically and otherwise.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than sett ing performance- or technology-ba sed standards for GS projects, EPA is adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: Careful Characterizati on of Site Risks

It is, of course, crucial that the final rule meet EPA's objective of protecting drinking water supplies. We are concerned, however, that some of the more stringent requirements being proposed for Class VI wells are not supported by findings of unique risks actu ally posed by CCS wells. EPA's regulations should be based upon an accurate characterizati on of the potential risks posed by the geologic sequestration of CO2 and be sp ecifically tailored accordingly to address those identified risks. This will ensure that EPA meets its obligation to provide appropriate pr otection of underground sources of drinking water, while avoiding unnecessary regulations that may hamper CCS or EOR projects from going forward or call into question the general safety of CO2 storage.

Regulations tailored to ensure proper site selection will in turn minimize the need for regulations crafted to respond to risks that, in such a context, would be extremely unlikely to occur. For exam ple, simply limiting CO2 injection to

Response: EPA believes that a detaile d, site-specific, geologic site characterization (required under §146.82) is essential to evaluating the presence and ad equacy of the various ge ologic features necessary to receive and confine in jected CO2 for GS. The requirements fo r geologic site ch aracterization are based on a long standing UIC regulatory framework de veloped to address specific risks to USDWs
p osed by injection. The Clas s VI GS requirements are tailored so th at they are appropriate for the unique nature of in j ectin g lar g e volumes of CO2 into a variet y of g eolo g ical formations for lon g -term stora g e. Commenter Name: Abbie Krebsbach Letter ID: 0235 Commenter Or g anization: Montana-Dakota Utilities Co. Comment ID: 23179

Commenter Name: Abbie Krebsbach Letter ID: 0235 Commenter Or g anization: Montana-Dakota Utilities Co. Comment ID: 23181Other EPA Comment Codes and Descriptions: 1930 1.4.4.2 Consultations with State, Tribal, and local Associations (e.g., GWPC, IOGCC) Comment: Limits on EPA Authority and Discretion

EPA should consider the significant intere sts and experience of the states in developing regulations. Mont ana-Dakota recognizes that in order to allow for effective site-specific determinations and to maintain essential regulatory flexibility, some amount of discretion must be vested in the UIC program director. At the same time, such disc retion should be bounded by the inclusion of relevant and appropriate considerati ons for making necessary determinations. In general, the rules should establish with sufficient clarity the factors to be taken into account and leave the precise de terminations to the permit process.

Response: The GS rule provides flexibility to determin e the suitability of a proposed site based on extensive, site-specific data. EPA believes that re quiring appropriate site ch aracterization by the owner or operator and providing an appropriate degree of flexibility to the Di rector to evaluate site-specific geologic data will afford the greatest protection of USDWs. The i ssuance of a UIC Class VI permit is determined based on evaluation of site-specific pe rmit information pursuant to the requirements at §§146.82 and 146.83.

EPA is developing guidance materials that describe the process of applying for and receiving primary enforcement responsibility (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administra tive issues on developing GS regulations that are the equivalent of minimum federal criteria and requirements. This guidance and training addresses areas where the Director is given discretion in implementing the requirements. Such requirements where the Director has discretion include: whether to require owners or operators to identify and characterize additional confining zones under §146.83, whether to require surface air monitoring and/or soil gas monitoring under §146.90, and whether to extend or shorten the post-injection site care period or approve an alternative post-injection site care timeframe as part of the permitting process under §146.93

Other EPA Comment Codes and Descriptions: 2300 1.7 Comments on the Alternatives Considered Comment: Section III -Proposed Regulatory Alternatives Subsection A -Proposed Alternative

Comment: Of the four alternatives consider ed by EPA, we appreciate the fact that the highly specific requireme nts approach of Alternative 4 was not chosen. However, even with the sel ected Alternative 3, we beli eve that EPA still must
p rovide some of the flexibility that wa s to be considered under Alternative 2. We are somewhat troubled by EPA's statem ent that it "did not select this alternative (Alternative 2) because it is not tailored to meet the unique challenges of long-term C02 storage. Whil e this option includes flexibility for
p ermit authorities to add requirements, EPA cannot be certain that the necessary adjustments would be made." Commenter Name: Abbie Krebsbach Letter ID: 0235 Commenter Or g anization: Montana-Dakota Utilities Co. Comment ID: 23193

Commenter Name: Robert E. Carter Jr. Letter ID: 0236 Commenter Or g anization: Indiana Department of Natural Resources (IDNR) Comment ID: 23205Response: Even though the Agency did not choose Altern ative 2, EPA agrees that flexibility is important to accommodate the varied conditions that may be encountered at GS sites while ensuring the
p rotection of USDWs. The technical requirements in Alternative 3 (and the final GS rule) build upon the long-standing UIC regulatory framework for deep wells and are appropriately tailored to address the unique nature of fullscale CO2 GS, including the volumes of CO2 to be injected, the buoya nt and mobile nature of the injectate, and its corrosivity in the presence of water. The regulation provides flex ibility for selection of appropriate sites and target formations (under §146.82), well construction specifics (under §146.86), and testing and monitoring regimes (under §146.90), provided the owner or operator can demonstr ate that the injection and storage will not endanger USDWs and that minimum requirements for the site are met.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: – EPA should apply a tiered set of site characterization requirements based on demonstrable and known site characteristic s. For example, potential sites that are deep saline formations located more than one kilometer below the surface are generally recognized as among the most fa vorable and secure site options for assuring public safety.[FN1] If such site s do not have a USDW aquifer located between it and the ground surface above, a more streamlined regulatory site characterization and risk review may be appropriate . On the other hand, an example of a potential site that may require a more rigorous site characterization and risk assessment are "sole source aquifers" which are aquifers that are a sole supply of water for a region and are critically important to protect. Some stakeholders may assert that there should be no CO2 storage above or below a sole source, a quifer. However, such a restriction would essentially prohibit storage in many western areas. Rather, a better approach would allow EPA to permit UIC Class VI wells in areas where it can be shown that there are sufficient caps and protections to preven t the migration of CO2 in overlying aquifers, even in proximity of aquifers designated as sole source. An early detection-monitoring program could be established to provide sufficient opportunity to mi tigate any unlikely release of CO2 from the geologic storage unit. Approaches like this illustrate how EPA can streamline UIC regulations for site charact erization and permit UIC Cl ass VI wells that first and foremost protect public safety, yet re flect a workable balance in adapting site characterization and risk assessments based on criteria adaptable to unique candidate sites.

Response: EPA believes that requiring appropriate, site-specific, site characterization by the owner or operator (under §146.82) and provi ding an appropriate degree of flexibility to the Director to evaluate site-specific geologic data will afford the grea test protection of USDWs from endangerment. EPA believes that it is important for the Director to ha ve as much site-specific information as possible in order to make an informed decision to permit inject ion for GS at a specific si te. This approach allows the permit writer to establish requirements consider ing varying site conditions eliminating the need for tiered requirements. GS in areas that may pose risks to USDWs, as a ssessed and identified by the owner or operator and the Director during the site selection process, woul d not be permitte d. EPA disagrees that a tiering system for GS sites or formations is appropriate. Instea d, the GS rule focuses on evaluating the suitabilit y of each site based on site-specific g eolo g ical and operational data. Commenter Name: Kevin Wantta j a Letter ID: 0248 Commenter Or g anization: Western Ener gy Suppl y and Transmission Associates Comment ID: 22246EPA adds that the final GS rule contains a provision (at §146.95) for owners or operators to apply for waivers from the requirement that injection be be low the lowermost USDW. EPA believes this waiver
p rovision will reduce potential limita tions on the re-permitting of Class II wells as Class VI wells,
p rovided they meet the requirements at §146.95 whil e still protecting USDWs from endangerment.

Comment: – EPA's proposed regulation needs to focus on accurate site specific characterization of the potential risks posed by geologic sequestration of CO2 and the UIC program needs to be specifical ly tailored accord ingly to address those identified risks. This will he lp EPA avoid over generalizing in its regulatory requirements. Too many genera l default provisions that presume universal application can be problematic. The geologic variability involved in different conceivable GS pr ojects needs to be specifi cally addressed, site-bysite, on issues ranging from site characterization to ar ea of review (AoR) to containment requirements. The regulations should encourage site-specific,
p erformance-based determinations at the permitting stage to handle these specific issues. This approach will work toward practical problem resolution without unduly alarming the public with generalizations about potential, but unrealistic risks and problems.

Response: EPA agrees that permitting deci sions for GS wells should be ba sed on site-specific factors. The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable fo r GS. Additionally, many of the permit requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testing and monitoring, and injec tion well plugging and post- injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Dir ectorial discretion and considerations for how that discretion would be exercised. The Agency believes th is balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each project, while providing consistency in permitting across the U.S.

Rather than setting performance or technology-based standards for GS projects, EPA is adopting a flexible approach, where operators of GS projects would develop and implement site-specific plans for delineating the AoR, testing and monitoring the site , performing corrective acti on, and post-injection site care. EPA believes that the plans—which would be reviewed and approved by the Director and
p eriodically updated throughout the life of the project—promote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a particular
p roject.

Other EPA Comment Codes and Descriptions: 2400 1.8 Comments on EPA's adaptive rulemaking
p rocess Comment: – Finally, EPA needs to build into this regulation a "learning and adjustment"
p rocess that gains feedback from implemen tation of the UIC for CO2 GS rule, and establish a periodic review process to ma ke adjustments and corrections to the rule based on experienced g ained in permittin g , operation, and clos ure of UIC/GS Commenter Name: Kevin Wantta j a Letter ID: 0248 Commenter Or g anization: Western Energy Supply and Transmission Associates Comment ID: 22248

Commenter Name: Kevin Wanttaja Letter ID: 0248 Commenter Or g anization: Western Ener gy Suppl y and Transmission Associates Comment ID: 22250wells. A CCS program of the size anticipa ted to meet national climate change CO2 abatement goals is going to create a very large endeavor that is bound to experience difficulties in its deployment and implementation. EPA needs a ready means to provide regulatory adjustments to reinforce the safety and success of this UIC / GS program as it proceeds in the future.

Response: EPA agrees that an adaptive approach to th e UIC GS rulemaking is appropriate. The Agency
p lans to use such an approach to ensure that USDWs are protected from endangerment and meet the
p otentially fast pace of GS deployment. EPA believes that an adaptive approach will allow regulatory development to proceed in time to meet the current and future demand for Class VI permits while recognizing the need to: continue to gather data from pilo t projects and other re search as it becomes available; and to enhance understanding of the techni cal and administrative as pects of GS deployment, operation, and technology developments.

EPA plans, every six years, to collect and review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requi rements are appropriate or necessary.

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: EPA should consider applying a tiered set of site characterization requirements based on demonstrable and known site char acteristics. For example, potential sites that are deep saline formations lo cated one or more kilometers below the ground surface are generally recognized as among the most favorable and secure site options for assuring public safe ty. If such sites do not have a Underground Source of Drinking Water (USDW) aquifer located between it and the ground surface above, a more streamlined regulatory site characterization and risk review may be appropriate.

On the other hand, an example of a potential site that may require a more rigorous site characterizati on and risk assessment are "sole source aquifers" which are aquifers that are the sole supply of water for a region and are critically important to prot ect. Some stakeholders may assert that there should be no CO2 storage above or below a sole source aquifer. However, such a restriction could essentiall y prohibit storage in many Western areas. Rather, a better approach would allow EPA to permit UIC Class VI wells in areas where it can be shown that there are sufficient caps and protections to prevent the migration of CO2 in overlying aquifers, even in proximity to aquifers designated as sole source. An early detection moni toring program could be established to
p rovide sufficient opportunity to mitigate any unlikely release of CO2 from geologic storage unit.

Approaches like this illustrate how EPA can streamline UIC regulations for site characterizations and permit UIC Class VI wells that first and foremost protect
p ublic safety, yet reflect a workable balance in adapting site characterization and risk assessments base d on criteria adaptable to unique candidate sites.

Response: EPA believes that requirin g appropriate, site-specific, site characterization b y the owner or Commenter Name: James T. Sims Letter ID: 0249 Commenter Or g anization: Western Business Roundtable Comment ID: 22263operator (under §146.82) and provi ding an appropriate degree of flexibility to the Director to evaluate site-specific geologic data will afford the grea test protection of USDWs from endangerment. EPA believes that it is important for the Director to ha ve as much site-specific information as possible in order to make an informed decision to permit inject ion for GS at a specific si te. This approach allows the permit writer to establish requirements consider ing varying site conditions eliminating the need for tiered requirements. GS in areas that may pose risks to USDWs, as a ssessed and identified by the owner or operator and the Director during the site selection process, woul d not be permitte d. EPA disagrees that a tiering system for GS sites or formations is appropriate. Instea d, the GS rule focuses on evaluating the suitability of a site based on site-specific geological and operational data.

EPA adds that the final GS rule contains a provision (at 146.95) for owners or operators to apply for waivers from the requirement that injection be be low the lowermost USDW. EPA believes this waiver
p rovision will reduce potential limita tions on the re-permitting of Class II wells as Class VI wells,
p rovided they meet the requirements at 146.95 whil e still protecting USDW s from endangerment.

Comment: 7. Avoid Over-Generalization in Regulations - We strongly urge EPA to avoid blanket prohibitions or arbitrary absolutes in the rule. As currently proposed, EPA’s regulations contain a number of defa ult provisions that presume universal application. We believe that approach is problematic. It is too early to fully understand precisely which methods or technologies will ultimately prove optimal.

Further, the geologic variability involved in different conceivable GS projects needs to be taken into account in issues ranging from site characterization to area of review (AOR) to containment requirements. The regulations should encourage site-specific, performance-ba sed determinations at the permitting stage to handle these important issues.

EPA should leave the door open for a range of injection sites and methods (some of which are not yet fully understood), provi ded that the Owner or Operator can show that the injection and storage wi ll be protective of drinking water supplies.

Response: EPA agrees that permitting deci sions for GS wells should be ba sed on site-specific factors. The GS rule requires owners or op erators to submit, and Directors to consider, extensive site-specific data, specified at §146.82, to de monstrate that a site is suitable fo r GS. Additionally, many of the permit requirements for GS wells are es tablished through individualized si te-specific plans for AoR and corrective action, testing and monitoring, and injec tion well plugging and post- injection site care and site closure. EPA adds that the final GS rule includes a balance of specific criteria to be met by the owner or operator and areas of Dir ectorial discretion and considerations for how that discretion would be exercised. The Agency believes th is balance allows for GS projects to be designed and permitted to address the unique, site-specific aspects of each project, while providing consistency in permitting across the U.S.

Rather than setting performance- or technology-based standards for GS projects, EPA is adopting a flexible approach, where operators of GS projects would develop and implement site-specific plans for delineating the AoR, testing and monitoring the site , performing corrective acti on, and post-injection site care. EPA believes that the plans—whic h would be reviewed and approved b y the Director and Commenter Name: James T. Sims Letter ID: 0249 Commenter Or g anization: Western Business Roundtable Comment ID: 22266p eriodically updated throughout the life of the project—promote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a particular
p roject.

Comment: Carbon capture and geologic sequestration enco mpasses more than the injection of captured CO2. The development of the entire enabling legal and regulatory framework, in which legal and regulatory barriers have been identified and resolved, to implement CCGS on a commerci al scale will requi re multi-media, multi-agency, and multi-statute consideration, including possible amendments of existing statutes. In addition to removing barriers to implementation, this legal and regulatory framewor k will need to be flexible and adaptable to facilitate the incorporation of new inform ation and experiences gained from the numerous pilot CO2 sequestration projects currently in their infancy. Whereas CO2 pipeline technology and le gal and regulatory framework have reached a status of relative maturity due primarily to th e use of CO2 in enhanced oil recovery for the past 30+ years, CO2 capture te chnology as applied to coal-fired power
p lants is just beginning to develop. Statutes and regulations governing the injection and storage of CO2 should be adaptive to the constraints of the other elements of an entire CCGS project (a nd vice versa) as they are identified.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA adds that it is using an ad aptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Comment: We believe that EPA should make efforts to keep the final rules flexible and avoid blanket prohibitions or absolute mandates. In several instances, EPA establishes default provisions that apply to all GS site s. Rather than imposing such a "one-size-fits-all" approach, we be lieve that EPA should use performancebased standards and allow site-specific fl exibility in meeting those standards. Furthermore, the rules should be consistent with alread y known principles under Commenter Name: Walter L. Bake r Letter ID: 0253 Commenter Or g anization: Utah Division of Water Quality Comment ID: 22339

Commenter Name: Mike Nasi Letter ID: 0254 Commenter Or g anization: Clean Coal Technolo gy Foundation of Texas Comment ID: 22358the Underground Injection C ontrol ("UIC") program, and ca re should be taken to avoid overestimating the risks associated wi th GS in order to ensure that the rules are not overly burdensome.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost USDW Comment: 1. Geologic Siting Section 1421( b)(3)(A) of the Safe Dr inking Water Act mandates that the UIC regulations de veloped by EPA "permit or pr ovide for consideration of varying geologic, hydrological, or histor ical conditions in different States and in different areas within a State. " Limiting CO2 injection to geologic formations that lie below the lowermost USDW is inconsistent with Congress' mandate, and thus, CCTF believes that a bl anket constraint that limits injection only to reservoirs below the USDW is ina ppropriate. A performance based approach that would place containment requirements on the acceptable reservoirs would be more sensible. Accordingly, we believe that the rule should allow a range of injection sites and methods provided that the ultimate performance based objective of protecting USDWs is achieved.

Response: EPA acknowledges that there are limited circum stances where injectio n above the lowermost USDW can be performed in a manner that protects USDWs from endangerment, as long as appropriate
p rotections are in place. The fina l GS rule at §146.95 establishes a pro cess by which owners or operators can seek a waiver of the Class VI injection depth requirements for injection into non-USDW formations above and/or between USDWs. Additionally, the fi nal GS rule does not cat egorically preclude or
p rohibit injection into any type of formation.

EPA believes that these requirements will ensure USDW protection while provi ding flexibility to UIC
p rogram Directors and owners or operators who unde rtake CO2 injection for GS. The Agency believes this approach: 1) responds to concerns about local and regional geologic stor age capacity limitations imposed by the proposed injection de pth requirements; 2) allows for a more site-specific assessment of injection depth for GS projects; 3) accommodates injection into differen t formation types; 4) allows for injection of CO2 for GS into non-USDWs above and/or between USDWs when appropriate and where it can be demonstrated that USDWs will be protected; and 5) responds to concerns about the use of aquifer exemptions for GS. Finally, EPA’s approach to addressing injection depth variability through a waiver
p rocess responds to concerns about future drinking wate r resource availability and the need to ensure that high quality water remains available in sufficient quantities to supply drinking water needs.

For additional information on the waiv er approach, please se e the final rule and preamble, as well as EPA's responses to comments on the Notice of Da ta Availability and Request for Comment. Commenter Name: Mike Nasi Letter ID: 0254 Commenter Or g anization: Clean Coal Technolo gy Foundation of Texas Comment ID: 22362Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: 3. Post-Closure Care

The proposal includes a defa ult monitoring period of 50 years after closure of an injection well, but fails to provide the necessary justification for setting the default monitoring period for this ti me period. CCTF does not believe that there is a sufficient connection between th is time period and the relative risks associated with geologic sequestration of CO2. Consistent wi th our previous comments, we urge EPA to incorporate perfor mance-based standards, so as to lead to site specific approaches. In this c ontext, we believe that post-injection site care should be based on site and project specific characteristics rather than a prescribed and lengthy time period, especially a default time period that does not seem to be supported by relevant literature.

Although provision is made in the proposed rule for a potential shortening of the post-closure monitoring period, the reality under the existing program is that permitting authoritie s almost without exception default to the maximum statutory monitoring period. Because there is no reason to believe that
p ermitting authorities will take a differen t approach here, the practical impact of including the 50 year period in the rule will be that operators will be required to monitor for that time period with only rare exceptions. There is simply no technical justification for such an extended monitoring period, especially given the decades of experien ce showing the 30 year monitoring period to be fully protective of human health and the environment.

Response: EPA disagrees with this comment. In determin ing the post-injection si te care timeframe for the proposed regulation, EPA reviewed industry repor ts, existing environmental programs, and initial GS research studies. EPA provided a synthesis of pertinen t results from GS m odeling studies in the
p reamble to the proposed regulation. Further explanation of this analysis was included in an EPAp repared background document that is available in th e federal docket, titled "Computational Modeling o f Underground Injection of Carbon Dioxide for Determination of Area-of-Review and Potential Risk to Underground Sources of Drinking Wate r." Based on review of these st udies, modeling results indicate that the CO2 plume stabilization may occur on the timeframe of 10-100 year s after the cessation of injection. EPA believes that a 50-year default post-injection site care timeframe is a reasonable midpoint, and has retained this in the final regulation.

EPA disagrees that a post-injection si te care timeframe of 50 years is ex cessive for most Class VI wells. While the 10- or 30-year timeframe suggested by some of these commenters may be within the timeframe suggested in so me studies, EPA believes that the poten tial risks of endangering USDWs will likely not decline within these timeframes and av ailable data, including data submitted by commenters, do not support a different default timeframe. However, EPA recognizes that alte rnative timeframes may be appropriate under limited, specific circumstances.

For this reason, the GS rule offers owners or opera tors flexibility regarding the duration of the PISC timeframe by: (1) allowing the Direct or discretion to shorten or lengt hen the PISC timeframe during the
p ost-injection period based on site-specific data, pursuant to requi rements at §146.93(b); or (2) affording the Director discretion to allow a Class VI well ow ner or operator to demonstr ate, during the permitting
p rocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures Commenter Name: Mike Nasi Letter ID: 0254 Commenter Or g anization: Clean Coal Technolo gy Foundation of Texas Comment ID: 22366non-endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mo nitoring and USDW impacts.

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe for
p ost-injection site care will be necessary in all buta limited number of cases. This default 50 year postinjection site care timeframe repres ents a reasonable and protective m onitoring period based on a review of research studies, industry repor ts, and existing envir onmental programs, and evaluation of public
comments.

Comment: We encourage EPA to consider seriously all of these comments which, if taken into consideration, could help create a more flexible, performance based Class VI program recognizing the charac teristics of CO2 injections.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Other EPA Comment Codes and Descriptions: 3820 2.3.1 Well construction procedures Comment: III A. 3 Proposed Injection We ll Construction Requirements

Q. EPA seeks comment on the proposed GS well requirements for depth of surface casing, the cementing of long-string casing, and construction with a packer set opposite a cemented interval.

IOGCC Response: IOGCC agrees with the need for adequate protection of USDWs and the
p roposed measures. However, Director discretion is necessary to address sitespecific conditions. Well construction s hould be evaluated so as to insure necessary protections of the USDWs, a nd should not be overly prescriptive.

Response: EPA agrees that, given the c ontinuing evolution of mate rial design and the numerous variables possible in a long-term GS project, listing specific require ments for casing and cement would not be appropriate. Rather, requiring that materials must have sufficient structural strength and be compatible with fluids with which the y ma y come in contact, in §146.86(b)(1), allows the owner or Commenter Name: Dianna Tickne r Letter ID: 0262 Commenter Or g anization: Peabod y Ener gy Comment ID: 22995

Letter ID: 0263 Commenter Or g anization: Interstate Oil & Gas Compact Commission Comment ID: 22802operator to determine the best casing and cementing design for each project based on information about the site and the planned injection and fo r the Director to approve that design.

See the discussion of Class VI well construction requi rements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment); 5260 2.8.2.3 Adjusting the post-injection timeframe (seeking comment) Comment: NACCSA urges the Agency to adopt a performance-based approach more in keeping with the actual risks posed by CCS projects. NACCSA believes that the site specific nature of CO2 storage projects will requi re each project to be judged on its own merit. If a project can show, at any time after the cessation of injection, that there is sufficiently small risk of enda ngerment to USDWs, monitoring should no longer be required. Given that under the proposed rule, the program director would retain discretion to lengthen or shorten th e PISC period as necessary to protect USDWs, a performance based approach is in keeping with the spirit of the draft rule. Furthermore, performance based approach is more in keeping with the realty of potential risks associated with CO2 storage would minimize disincentivization of CCS projects wh ile providing an equivalent degree of protection for USDWs. NACCSA believes that the performance-based approach, currently proposed by EPA as an element of the rule, would be beneficial to
p roject operators and investors and for th e protection of USDWs. The final rule should include specific and appropriate ci rcumstances that the program director will consider in exercising discretion in this regard, so that project operators and investors have a clear idea of the bar they will be required to meet in order to close out the PISC period.

Response: As described above, EPA agrees that there will be circumstances where it can be demonstrated in less than 50 years that the pl ume and pressure front no longer pose a risk of endangerment to USDWs. For this reason, the GS rule offers owners or operators flexibility regarding the duration of the PISC timeframe by: (1) allowing th e Director discretion to shorten or lengthen the PISC timeframe during the post-inj ection period based on site-specific data, pursuant to requirements at §146.93(b); or (2) affording the Direct or discretion to allow a Class VI well owner or operator to demonstrate, during the permitting pr ocess based on substantial data, that an alternative PISC timeframe may be appropriate if it ensures non-endangermen t of USDWs pursuant to requirements at §146.93(c).

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure mon itoring and USDW impacts. Commenter Name: Michael Moore Letter ID: 0265 Commenter Or g anization: North American Carbon Capture & Storage Association (NACCSA) Comment ID: 22868Comment: (1) Appropriate Level of Regulation -Recognizing mandates under the Safe Drinking Water Act (SDWA) for protection of drinking water, there are serious concerns about the overall burdens and resource requirements of the proposed rules. This concern includes considerat ion of how such rules may inhibit implementation of carbon capture and storage technology.

The "tailoring," as described by EPA, of the basic regulations for injection of nonhazardous industrial waste to the unique characteristics of CO2 injection has resulted in proposed requirements that in many aspects exceed the stringency of those for injection of hazardous waste. This excessive stringency is particularly
p resent in the proposed requi rements for iterative comput ational modeling of the CO2 plume and pressure front, and the m odel's proposed influence on a project's area of review, corrective action, monitoring, post-injection site care, closure, and financial assurance. Many of these concerns have been expressed in the CO2-GS Workgroup process by state and federal staff responsible for regulation of the nation's largest conc entration of Class I hazardous waste injection wells. As an additional cons ideration, the lack of significant environmental or health risks evident from our state's experience in CO2 injection for enhanced recovery of oil and gas under regulation by the Railroad Commission does not provide a supporting basis for the unprecedented stringency of Class VI requirements as proposed by EPA.

Response: EPA disagrees that the Class VI requireme nts are overly stringent; instead, the GS requirements are tailored to the uni que nature of GS, including the la rge volumes of CO2 injected, its buoyancy and potential corrosivity in the presence of water, and impurities in the CO2 stream. EPA believes these tailored requirements are more appropriate than Class I or Class II requirements. Please see the remainder of EPA's responses to this commen t for further details. For additional information on EPA's final regulatory appr oach, please see the final rule and pream ble as well as the rulemaking docket.

The Agency believes that the Class VI requireme nts balance site-specific flexibility with USDW
p rotection. Rather than setting performance or t echnology-based standards for GS projects, EPA is adopting a flexible approach, where operators of GS projec ts would develop and im plement site-specific
p lans for delineating the AoR, te sting and monitoring the site, pe rforming corrective action, and postinjection site care. EPA believes that the plans—wh ich would be reviewed a nd approved by the Director and periodically updated throughout th e life of the project—promot e an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a particular
p roject.

Other EPA Comment Codes and Descriptions: 1480 1.2.2.2.2 CO2 is not a pollutant Comment: With regard to the appropriate level of regulation, EPA has described the rule development as an adaptive process occurring over a period of years with careful consideration of stakeholder and general publ ic comment, and results of research including experimental CO2 injection projects worldwide. This process includes the possibility of future revision of the final adopted rules in response to accumulating knowledge from project operational experi ence, research, and increasin g public confidence in captu re and sequestration technolo gy . Concern Commenter Name: Mark Vicker y Letter ID: 0280 Commenter Or g anization: Texas Commission on Environmental Qualit y Comment ID: 24098

Commenter Name: Mark Vickery Letter ID: 0280 Commenter Or g anization: Texas Commission on Environmental Qualit y Comment ID: 24105however remains that overly burdensome re gulations may seriously impede the technology in a manner not easily co rrectable by later rule revisions, especially considering the experience from CO2 injection in Class II well enhanced recovery projects indicating no significant environmental or health risks. EPA should strive to protect drinking water sources as mandated by the SDWA while imposing reasonable and prov en controls on carbon sequestration, not onerous burdens without risk-based just ification or cost effectiveness. Reasonable and proven controls will encourage responsible parties to voluntarily implement carbon capture and storage t echnology. In short, carbon is not a hazardous material and responsible indus tries need incentives, rather than unreasonable stringency, to participate in the program. Otherwise, the United States may not realize the benefi ts of carbon geosequestration.

Response: EPA believes the final GS rule addresses the commenter’s concern that it protects drinking water sources while imposing reas onable and proven controls. The GS rulemaking builds upon decades of knowledge about safe injection practices regula ted by the UIC Program (including the oil and gas industry’s decades of expe rience injecting CO2 for the purpose of ER ). The final GS rule contains new requirements for Class VI wells that are tailored to address the unique nature of full-scale CO2 GS, including the injection volumes anticipated for long-term storage, th e buoyant nature of the injectate, its corrosivity in the presence of water, and its mobility within subsurface geologic formations.

EPA remains committed to an adaptive approach. Th e Agency plans to, every six years, collect and review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary. An adaptive approach will allow regulatory development to proceed in time to meet the current and future demands for Class VI perm its while EPA continues to gather data from pilot
p rojects and other research as it becomes available.

EPA adds that the intent of the GS rule is not to promote GS. Rather, the purpose of the GS regulation is to assure that, where deployed, GS is conducted in a manner that pr otects USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 5610 2.11.1 Allowing partial primacy for Class VI wells (seeking comment) Comment: (3) Flexibility and Streamlining in Class VI Program Primacy Considerations - TCEQ concurs with EPA's assessment that current options for injection of CO2 include Class I, ClassII, a nd ClassV wells. Accordingly, under state law, injection of CO2 in Texas will be regulated by eith er the TCEQ or the Railroad Commission (RRC). Noting the RRC's responsibility for Class II injection (including CO2 injection for enhanced recovery of oil and gas), TCEQ is responsible for Class I and most of Class V (including experiment al injection of CO 2). Class VI as
p roposed by EPA, under state law, would a ppear to be in TC EQ's jurisdiction. Section 27.022, Texas Water Code provides: "The commission has jurisdiction over the injection of carbon dioxide produced by a clean coal project, to the extent authorized by federal law, into a zone that is below the base of usable quality water and that is not productive of oil, ga s, or geothermal resources". However, such jurisdictional lines are subject to change by state legislation. Flexibility will therefore be needed in federal authorization of the Class VI well pro g ram at whichever a g enc y is desi g nated b y the state le g islature. Commenter Name: Mark Vicker y Letter ID: 0280 Commenter Or g anization: Texas Commission on Environmental Quality Comment ID: 24111Flexibility in this sense primarily me ans free from constraints that EPA has traditionally imposed by bundli ng various well classes into an "all or nothing" condition for program primacy.

Response: EPA agrees with commenters that states shoul d be allowed to obtain primacy for Class VI wells independently of other well classes, and will allow independent primacy for Class VI wells under §145.1(i) of the final GS rule. EPA believes that al lowing independent Class VI primacy may encourage states to take responsibility for implementation of Class VI regulations and provide for a more comprehensive approach to managing CCS projects by promoting the integration of GS activities under SDWA into a broader framework for managing CCS. Furthermore, GS operations involve ancillary activities (e.g., pipeline operations, pore space owners hip, land use rights, and surface access) for which states can call upon other authorities that exist at the state level (but outside UI C authority) to provide a more comprehensive CCS management approach.

EPA also believes that allowing states to apply only for Class VI primacy will shorten the primacy approval process for states. EPA's willingness to accept independent prim acy applications for Class VI wells represents a shift in its longstanding policy of discouraging "partial primacy." It is very important to note that this shift in policy allowing for Clas s VI primacy does not apply to any other well Class under Section 1422. EPA will continue to discourage applications for partial prim acy for all other well types under Section 1422.

EPA clarifies that states should be able to obtain pr imacy for Class VI wells i ndependent of other well classes provided they develop regulations that ar e at least as stringent as the minimum Federal requirements (e.g., permitting, inspection, operation, monitoring, and recor dkeeping requirements)
p rovided in the final GS rule. EPA believes that existing programs can adapt their expertise to the new requirements for Class VI we lls and will be able to develop a primacy application for Class VI wells under section 1422 of SDWA and ensure that their GS programs integrate into national climate change
p riorities and protect USDWs from endangerment.

EPA also clarifies that primacy is gr anted to a state, not to any agency within that state, and states are free to choose which agency will implement the Cl ass VI program—for instance, an environmental quality protection agency (non-Class II) or the stat e's traditional oil and gas regulatory agency (Class II)—as long as the program meets the minimum Fede ral requirements for Class VI wells as required under section 1422 of SDWA. Some states administer their program for all injection well classes through a single agency, whereas other States elect to divide the program between agencies. For example, in most States, the Class II program is run by an oil and gas agency and other well classes are run by a State environmental agency (e.g., the Ok lahoma Corporation Commission oversees Class II wells in the State, and the Oklahoma Department of Environmental Quality overs ees other well classes). Additionally, several States allow th eir oil and gas agencies to administer their UIC program for specific well classes or subclasses provided they meet all Federal requirements (e.g., the Texas Railroad Commission oversees Class III brine-mining wells and Class V geothermal wells in Texas). EPA believes that retaining this flexibility for States to identify the appropriate ag ency to oversee Class VI wells will address commenters’ concerns that Stat es should be afforded the opportunity to determine which agency should oversee Class VI wells, and recognizes the existing expertise of both State oil and gas agencies and environmental agencies.

Comment: Our second message to the EPA today addr esses the regulatory flexibility. We b elieve that the a g enc y should be cautious in overl y prescriptive re g ulation, Commenter Name: Karl R. Moo r Letter ID: 0501 Commenter Or g anization: Southern Compan y Comment ID: 21162one size fits all approaches to siting. No two geological fo rmations are the same, no two CCS projects will be the same. And the geological formations in which CO2 is injected will be defined by a number of characteristics. We believe the many instances and the regulation has chosen to tie with the regulated entities to a -- whether it be -- of responsible, duration of responsibility award, financial assurance responsibility.

In all of these instances where EPA has said that there is one defining characteristic, it will tie the regulated entity's hands to an existing set, a new set of regulatory prescriptions with the EPA has not done good service to the industry or to the development of GS technology?

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Comment: Next, EPA should also reconsider its pr oposed well construction and operation requirements, which are much more prescr iptive and rigorous than necessary, and do not reflect industry's 35 plus years of success in rejecting CO2 under the Class II UIC program.

Response: EPA disagrees that the Class VI requireme nts are overly stringent; instead, the GS requirements are tailored to the uni que nature of GS, including the la rge volumes of CO2 injected, its buoyancy and potential corrosivity in the presence of water, and impurities in the CO2 stream. EPA believes these tailored requirements are more appropriate than Class I or Class II requirements. Please see the remainder of EPA's responses to this commen t for further details. For additional information on EPA's final regulatory appr oach, please see the final rule and pream ble as well as the rulemaking docket.

The Agency believes that the Class VI requireme nts balance site-specific flexibility with USDW
p rotection. Rather than setting performance or t echnology-based standards for GS projects, EPA is adopting a flexible approach, where operators of GS projec ts would develop and im plement site-specific
p lans for delineating the AoR, te sting and monitoring the site, pe rforming corrective action, and postinjection site care. EPA believes that the plans—wh ich would be reviewed a nd approved by the Director and periodically updated throughout th e life of the project—promot e an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a particular
p roject.

Comment: In conclusion, API shares the same goal as EPA, to develop rules that facilitate the safe, secure, long-term storage of CO2. API is concerned though that by b ein g overl y prescriptive in desi g nin g the new well class the proposed rule Commenter Name: Michele Schoeppe r Letter ID: 0503 Commenter Or g anization: American Petroleum Institute Comment ID: 21176

Commenter Name: Michele Schoeppe r Letter ID: 0503 Commenter Or g anization: American Petroleum Institute Comment ID: 21179hinder the deployment of CCS and could have the unanticipated consequence of hindering innovations that c ould improve both well secu rity and performance.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Comment: So, in conclusion, wells are indeed a fundamental component of a geologic storage system, having appropriate design, construction, and operating expectations for these wells is necessary to ensure delivery of a secure storage CO2.

Site-specific performance base d guidelines, as per the well-related example that I note previously, do serve to, do serve the purpose of requiring application of appropriate technological solu tions to protect USDWs.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Comment: I also want to agree with the American Pe troleum Institute and Iain Wright, that the standard for site clos ure in the proposed rule needs to be improved. We agree that the standards should be site-specific and performance based.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue b etween the operator and the Director that will encoura g e use of the most appropriate technolo g ies for a Commenter Name: Brian Williams Letter ID: 0507 Commenter Or g anization: BP Alternative Ener gy Comment ID: 21169

Commenter Name: Scott Anderson Letter ID: 0510 Commenter Or g anization: Environmental Defense Fun d Comment ID: 21216p articular project.

Comment: defined using reasonable risk based crit eria. EPA should also reconsider its
p roposed well construction and operating requirements which are much more
p rescriptive and rigorous than necessary and do not reflect industries thirtyfive plus years of success in injecti ng CO2 under the Class II UIC program.

Response: EPA disagrees that the Class VI requireme nts are overly stringent; instead, the GS requirements are tailored to the uni que nature of GS, including the la rge volumes of CO2 injected, its buoyancy and potential corrosivity in the presence of water, and impurities in the CO2 stream. EPA believes these tailored requirements are more appropriate than Class I or Class II requirements. Please see the remainder of EPA's responses to this commen t for further details. For additional information on EPA's final regulatory appr oach, please see the final rule and pream ble as well as the rulemaking docket.

The Agency believes that the Class VI requireme nts balance site-specific flexibility with USDW
p rotection. Rather than setting performance or t echnology-based standards for GS projects, EPA is adopting a flexible approach, where operators of GS projec ts would develop and im plement site-specific
p lans for delineating the AoR, te sting and monitoring the site, pe rforming corrective action, and postinjection site care. EPA believes that the plans—wh ich would be reviewed a nd approved by the Director and periodically updated throughout th e life of the project—promot e an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a particular
p roject.

Comment: In conclusion, API shares th e same goal as EPA to deve lop rules that facilitate the safe, secure, long term storage of CO 2. API is concerned that if by being overly prescriptive in designing a new well class, the proposed rule will hinder the development of CCS and could have the unanticipated consequence of hindering the innovations that could im prove both well security and performance. CCS is

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking. Commenter Name: Steve Crookshan k Letter ID: 0523 Commenter Or g anization: American Petroleum Institute (API) Comment ID: 21359

Commenter Name: Steve Crookshan k Letter ID: 0523 Commenter Or g anization: American Petroleum Institute (API) Comment ID: 21362

Commenter Name: George Peridas Letter ID: 0534 Commenter Or g anization: Natural Resources Defense Council (NRDC) Comment ID: 21455Comment: trigger for major revisions to the rule. I do not think that is necessary. I mean, it really does depend on how the rule is phrased and to what extent it is flexible and performance based and I think if I weigh in that direction.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Comment: The fundamental challenge confronting EPA in this rulemaking is to establish a cost effective and environm entally sound regulatory program to cover a range of operations for which the technology will not be commercially deployed for a number of years. To meet this challenge and to establish a workable regulatory framework over the coming decades for th e long term storage of carbon dioxide, EPA must craft regulations with flexibilit y so that it may be fine tuned as industry and regulations alike gain experi ence with large scale carbon dioxide sequestration.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

EPA clarifies that the Class VI GS requirements ar e designed to ensure that , where deployed, GS is conducted in a manner that protects USDWs from endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Comment: Because information related to carbon seque stration is sure to develop, Ameren urges EPA to avoid blanket probations or arbitrary absolutes in the final rule. We agree that the standard underlying pr otective rule requirements for carbon dioxide sequestration is the protection of underground sources of drinking water. However, because it is difficul t to know at this point what future technologies will be developed for inj ection and long term storage of carbon dioxide in the manner that is protective of these drinking water sources. But b ecause there is, there should be a si g nificant demand for the capacit y to store Commenter Name: Paul Pike Letter ID: 0535 Commenter Or g anization: Ameren Corporation on behalf of Utility Solid Waste Activities Group (USWAG) Comment ID: 21433

Commenter Name: Paul Pike Letter ID: 0535 Commenter Or g anization: Ameren Corporation on behalf of Utility Solid Waste Activities Group (USWAG) Comment ID: 21434this CO2, EPA should not prematurely pr eclude injection in certain specific types of sites or through ce rtain methods. The final ru le should leave the door open for a range of injection options, si tes and methods, some of which are unrecognized or even unknowable at this point in time provided that the ltimate objective of protecting the underground sour ces of drinking water is achieved.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

To address the comment that the rule should accommodate future technological developments related to GS, EPA adds that it is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS regul ation, EPA plans, every six years, to collect and review project data on GS research projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: Because of wildly varied ch aracteristics and limitations of sites and projects, it is important to incorporate performan ce based standards into the final rule waiting for site specific approach to re quirements for site review, reevaluation and post injection site care and closure.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Comment Code: 1260 1.1.1.5 More certainty/stringency is needed



### Individual Comments

Other EPA Comment Codes and Descriptions: 1500 1.2.2.2.4 Some other agency should regulate Commenter Name: Paul Pike Letter ID: 0535 Commenter Or g anization: Ameren Corporation on behalf of Utility Solid Waste Activities Group (USWAG) Comment ID: 21439

Commenter Name: Emily Rochon Letter ID: 0129 Commenter Or g anization: Greenpeace International Comment ID: 23076GS; 1510 1.2.2.3 Need for additional study Comment: that are consistent with wh at Greenpeace believes must be done, however a more comprehensive regulatory structure is wh at is truly needed before any carbon capture and sequestration project can be allowed to start.

Response: As described above, EPA believes that establ ishing a regulatory framework for the future development and deployment of CC S technology provides a framework fo r injecting CO2 so that the activity does not result in endangerment of USDWs.

Further, as described above, the Agency will conti nue to coordinate on GS and CCS related issues to minimize redundancy and maximize efficiencies for owners or operat ors. For additional information,
p lease see the discussion entitled "H ow Does This Rulemaking Relate to Other Federal Authorities and GS and CCS Activities?" in the preamble to the final GS rule.

Other EPA Comment Codes and Descriptions: 1970 1.4.4.6 Need for other consultations Comment: II. Regulatory Oversight

Regional Advisory Boards: Establish a Ca rbon Capture and Sequestration Advisory Board for each of the EPA's ten regiona l offices (according to guidelines under 40 CFR 25.7), in order to optimally ad minister a "Tailo red Requirements Approach" that applies national standards which are adaptive to a variety of regional differences in geological form ations, natural resources, weather
p atterns, industrial operations, and applicable state laws.

Response: EPA clarifies that establishing a Carbon Captur e and Sequestration Advisory Board is out of the scope of the GS rulemaking. EPA adds that the Ag ency plans to collect and review data every six years on GS projects to determine whether the appropriate amount and t ypes of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary. As part of this adaptive rulemaking approac h, EPA will consult with a variety of stakeholders, including the National Drinki ng Water Advisory Council, associations and organizations, ORD, and experts to ensure that im plementation of the national Class VI program is based on the best available science.

Other EPA Comment Codes and Descriptions: 1970 1.4.4.6 Need for other consultations Comment: Regulatory Oversight

D. Regional Advisory Boards

Recommendation D: Establ ish a Carbon Capture and Sequestration Advisor y Board Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Ener gy and Climate Chan g e Comment ID: 21581

Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Ener gy and Climate Chan g e Comment ID: 21606for each of the EPA's ten regional offices (according to guidelines under 40 CFR 25.7), in order to optimally administer a "Tailored Requ irements Approach" that applies national standards which are ad aptive to a variety of regional differences in geological formations, natural resour ces, weather patterns, industrial operations, and a pplicable state laws.

Response: EPA will continue to consult with a variety of stakeholders, including the National Drinking Water Advisory Council, associati ons and organizations, ORD, and experts; review permits; and continue to hold workshops to build expertise and ensure that implem entation of the national program is based on the best available science. The Agency plan s to collect and review data every six years on GS
p rojects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Other EPA Comment Codes and Descriptions: 5600 2.11 Comments related to UIC Program primacy for Class VI wells Comment: 2.EPA should set standards and criteria that will result in reasonably consistent implementation and result s regardless of geographic location.

3.EPA should establish a hierarchy of authority for decision making and oversight, to ensure interstate and inte r- jurisdictional conflicts are avoided. In this, Global appreciates that some states have moved ahead to implement carbon management programs. However, it is our view that effective and early implementation will be best served by consistenc y across the board. We therefore encourage EPA to review the pr ograms of all states and select the common threads that are most suitable to early and effective implementation.

Response: EPA agrees that it is important to balance fl exibility and national consistency. The GS rule sets forth minimum Federal requirements, tailored to the unique nature of CO2 GS, which must be met in order to ensure USDW protection from e ndangerment. EPA acknowle dges the importance of flexibility for certain Class VI well requirements given the va riety of geologic settings in which GS will be applied and therefore affords the Director discretion when making permitting decisions. Such requirements where the Director ha s discretion include whether to re quire owners or operators to identify and characterize additiona l confining zones, as specified in §146.83, whether to require surface air monitoring and/or soil gas monitoring, as specified in §146.90, and whether to extend or shorten the
p ost-injection site care period or appr ove an alternative post-injection site care timeframe as part of the
p ermitting process, as specified in §146.93. The GS rule balances the need for site-specific decisions with the need for minimum standards to ensure national consistency a nd USDW protection from endangerment while also ensuring that states have the data they need to make permitting decisions. EPA Headquarters also plans to review initial permits to ensure that the final ru le, including all permitting decisions, are implemented consistently, and to ensure that USDW protection go als are consistently met across differing geologic situations.

EPA understands that the CO2 plumes for large GS proj ects may cross State, Trib al, Territorial, or EPA Regional boundaries. The final GS rule, at §146.82(a)(2), requires the owner or ope rator to identify all State, Tribal, and Territorial boundaries within the AoR. Based on this information, the Director must
p rovide written notification to all St ates, Tribes, and Territor ies to inform them of the permit application, as specified in §146.82(b), and ensure that the y are involved in an y necessar y processes (e. g ., Commenter Name: Dwi g ht Lockwood, PE, QEP Letter ID: 0141 Commenter Or g anization: Global Ener gy , Inc. Comment ID: 23094development of the emergency and remedial res ponse plan, as specified in §146.94). The Agency encourages transparency in the permitting process and anticipates that State-State/State-Tribal communication on GS permitting will facilitate information shari ng and encourage safe, protective
p rojects.

Because some GS projects will require coordination acro ss State, Tribal, and Territorial jurisdictions, the Agency will work with the appropriate entities to facilitate communicati on among States, Tribes, and Territories during the implementation phase of the GS regulation. Such communication may involve other organizations such as the Sierra Club, NDWAC, associations, and other experts. However, the responsibility for addressing such s ubjects ultimately rests with the St ates, Tribes, and Territories with
p rimacy. EPA is developing primacy implementation ma terials for states that describe recommended approaches to addressing trans-bounda ry issues during the permitting of Class VI wells under the GS regulation. The materials will be available at http://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

In response to questions about which state or regi on would oversee the permit for projects where the AoR spans State, Tribal, or Territorial boundaries, EPA clarifies that issuance and oversight of a GS
p ermit, including any associated AoR boundary-related coordination, is the responsibility of the primacy (State, Tribe, or Territory) or re gional DI program in the state wher e the injection well is located.

Comment: EPRI COMMENT#1: The proposed rule allows the EPA Director to make discretionary decisions regarding numerous program elements includ ing, but not limited to, characterization, monitoring, testing, and site closure. EPRI urges EPA to
p rovide clarity in the fina l rule regarding the techni cal or administrative criteria that trigger the need fo r discretionary decision making.

Response: EPA is developing guidances fo r States that describe the process of appl ying for and receiving primary enforcement au thority (primacy) for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues on developing GS regulations that are the equivalent of minimum fede ral criteria and requirements. The guidan ce will describe ar eas of Directorial discretion and considerations for how that discretion would be exercise d. This guidance will be available on EPA’s website at http://w ater.epa.gov/type/groundwater/u ic/wells_sequestration.cfm.

The Agency believes that the Class VI requireme nts balance site-specific flexibility with USDW
p rotection. Rather than setting performance or t echnology-based standards for GS projects, EPA is adopting a flexible approach, where operators of GS projec ts would develop and im plement site-specific
p lans for delineating the AoR, te sting and monitoring the site, pe rforming corrective action, and postinjection site care. EPA believes that the plans—wh ich would be reviewed a nd approved by the Director and periodically updated throughout th e life of the project—promot e an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a particular
p roject.

Comment: experience is for the power plant sector. Regardless of the actual future volume of injection (or perhaps the ultimately limited success of carbon separation and ultimate in j ection), a practical Class VI permittin g s y stem is essential. Given Commenter Name: Michael J. Mille r Letter ID: 0168 Commenter Or g anization: Electric Power Resear ch Institute (EPRI) Comment ID: 22491

Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23391the direct impact th is program will have on the el ectric utility industry, APPA genuinely appreciates EPA's goal of establ ishing a regulatory regime that will
p rovide "certainty" and "transparency" to what requirements would apply to owners/operators who engage in Class VI CO2 injection. I d. at 43496 (July 25, 2008). At the same time, it is crucial for the regulations to reflect the

Response: EPA clarifies that the Class VI GS requirement s are designed to ensure that, where deployed, GS is conducted in a manner that protects USDWs fr om endangerment. Encouraging investment in CCS
p rojects and facilitating depl oyment are outside the scope of the GS rulemaking.

Other EPA Comment Codes and Descriptions: 1620 1.3.2 Induced seismicity Comment: Because information and t echnology related to carbon sequestration are sure to develop as more experience is gained, APPA urges EPA to do what it can avoid the use of arbitrary or blanke t prohibitions or absolutes in the EPA final rule. However, APPA believes that there are so me common sense prohibitions that may be j ustifiable. For example, EPA should have in the final rule an explanation, consistent with the Class I program, that seismic-induced subsurface conveyance risks such as major faults, or proxi mity to sole source aquifer [FN5]
p rotections are essentia l. Sole source aquifers are not the same as deep saline aquifers. APPA believes there are some prohibitions that are key to protection of USDWs. At the same time we do not want to contribute to "NIMBY" or "not in my backyard" or "NUMBY" - or "not under my ba ck yard". What APPA asks for in the context of seismicity issues are clear-cut and understandable parameters or USGS guidelines so that power plant owner/ope rators don't pursue a geologic formation thinking that it is eligible only to learn that the EPA has used a USGS designation on seismic risks that would re nder it disqualified later in the
p ermitting process. APPA asks that wh en the EPA or state directors make seismicity conditions that these be subject to notice and comment and be
p ublished in the Federal Register and the state equivalent publication. It would be terrible to have a power plant ow ner/operator spend time and significant money pursuing a geologic formation only to learn after he had spent many hundreds of thousands of dollars that the site did not meet the EPA’s seismic risk or USGS seismic requirements. Seismici ty risk avoidance is a new factor for thermal or fossil plants and not one with which we have experience. APPA includes in the Appendix a paper from an NETL-funded study on seismic activity induced by injection of CO2 into deep sa line aquifers [FN6 ] and an article regarding the Greek government’s concer ns with injection of CO2 in the Mediterranean. [FN7] [S ee EPA-HQ-OW-2008-0390-0169.pdf for these documents.] Including these references to seismic issues does not mean that APPA fears that CO2 will cause seismic activity. Instead A PPA does not want to see APPA member utilities pursue geology which has underlyi ng seismic risks that are unknown to the power sector (and perhaps to the state agencies) and misuse critical resources, time and money pursuing that location for permitti ng only to find out later that they must start again. Most loca tions in the U.S. have not had recent seismic data assessed at the "fine granul ar" level needed to target the right formations for carbon dioxide geosequest ration. This will necessitate the support of United States Geologic Survey and other agencies. Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23396[FN5] A sole source aquifer (SSA) is an underground water supply designated by the U.S. EPA as the "sole or principal" source of drinking water for an area under Section 1424(e) the Safe Drinking Wat er Act of 1974. "Sole or principal" has been interpreted to mean that the a quifer must supply at least 50 percent of the drinking water to persons living ove r the aquifer; there should be no alternate and feasible sources of drinki ng water that could replace the aquifer.

[FN6] Issues Related to Seismic Activity Induced by the Injection of CO2 in Deep Saline Aquifers, Joel Sminchak and Neeraj Gupta, Battelle Memorial Institute

[FN7] "Why doesn't Greece like carbon captu re?" Leigh Phillips, EU Observer, 9/23/08, http://euobserver.com/19/26794

Response: The GS rule, at §146.82(a)(5) requires prospective owners or operators to submit information on all USDWs within the AoR. EPA expects that this information will include id entification of any sole source aquifers. The GS rule also requires operators to submit extensive information about the site, including the geologic characteristics of the injection and confining zones, to demonstrate that the injected CO2 will remain within the target formati on. The Director must consider this information when determining whether GS is accepta ble at a given site. EPA expects that during this evaluation the Director will consider the pot ential impact of the GS proj ect on any sole source aquifers.

Regarding seismicity, EPA acknowledges that induced seis micity is a risk that may be associated with GS but maintains that the risk is low (IPCC, 2005). The GS rule contains several requirements to address seismic risk. First, as part of the site char acterization process, owners or operators must submit information about the seismic histor y of and seismic sources near a pr oposed GS site, data on known or suspected faults in the AoR, geom echanical information on fractures, stress, ductility, rock strength, and in situ fluid pressures within th e confining zone as specified in §146.82(a)(3). This information is evaluated by the Director, who determines the suitabil ity of a potential project site for GS. Any sites with the potential for reopening or reactivation of faults or unacceptable se ismic risk that could otherwise interfere with containment will not be permitted as GS sites. During injection, the pressure in the injection zone must not exceed 90 percent of the fracture pressure of the injection zone as specified in §146.88(a); this requirement is intended to prevent the opening of fractures or faults through over
p ressurization of the injection zone.

EPA clarifies that the rule doe s not contain any specific requi rements describing "seismically appropriate" areas, and doe s not believe this is appropriate for all sites. EPA believes such determinations should be made on a site-specific basis. If such information is available, and the Director determines it to be relevant to the site characteri zation, it is in their aut hority to require detailed evaluations. However, EPA disagrees that this shoul d be a requirement for all GS projects. In many cases, UIC Directors will have exte nsive knowledge of which areas are su itable for GS, but clarifies that it is the responsibility of Class VI permit applicants to demonstrate the suitability of a particular site or formation. It is the responsibility of the Director to evaluate the information collected and submitted by the owner or operator to determ ine whether a permit for GS at the site is appropriate.

EPA is developing guidance on site ch aracterization for GS projects to assist owners or operators and Directors in evaluating permit requirements and applications under §146.82. The guidance provides recommendations to owners or ope rators regarding information to support characterizing the regional geology and hydrogeology of a proposed GS site as we ll as how to perform th e necessary geochemical, geomechanical, and geophysical analyses of the inj ection and confining zone. EPA expects that this guidance will assist permit wr iters/UIC Directors in making an objective decision about requiring additional confining layers. The guidance can be found on EPA’s website athttp://water.epa.gov/type/groundwat er/uic/wells_sequestration.cfm.

Other EPA Comment Codes and Descriptions: 1420 1.2.1.1 Support the GS rulemaking Comment: VII. Conclusion

ELPC and ETIP support many portions of the EPA's proposed regulations and commend the EPA for implementing safeguard s for GS that go beyond those required for other classes of injection wells. Fo r example, we are pleased to see that EPA has provided flexibility in the choice of construction materials used by well owners while preserving rigorous construction standards. Our primary objection to the regulations, however, is that they constitute a piecemeal approach to regulation ofGS (and CCS), thus leaving several issues unaccounted for. The lack of certainty on issues of liability, financ ial assurance, and well-closure standards, could both stif le the use ofGS as a climate change mitigation tool and place the public at greater risk.

Response: EPA acknowledges that GS falls within the broader context of CCS and the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordina ted with other Agency program of fices and across federal agencies (e.g., with the Department of Energy; United St ates Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcem ent, formerly the Minerals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applic ability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

EPA recognizes that liability is an important issue to owners or operators; however the Agency does not have authority under the SDWA to tran sfer long term liability from owne rs or operators to the state or federal government. Therefore, liabil ity remains with the owner or ope rator. EPA notes that the final rule clarifies the requirements for the use of financial responsibility instruments for GS. In addition, the final rule requires owners or opera tors to address well plugging in well plugging plans submitted with the Class VI permit appl ication. EPA is developing guidance manuals for owne rs or operators that describe the financial responsib ility and injection well plugging requirements in the GS rule.

Other EPA Comment Codes and Descriptions: 1250 1.1.1.4 Flexibility is needed (performance- b ased standards) Comment: 4. For an activity covering such a diverse geographic, geologic, and commercial spectrum as GS, NiSource be lieves it is essential to incorporate considerable regulatory flexibilit y. However, some relatively high minimum st andards of technical requirements should be established in ke y areas. While this ma y sound Commenter Name: Wend y Jacobs Letter ID: 0183 Commenter Or g anization: Harvard Law School Environmental Law and Policy Cente r Comment ID: 25169

Commenter Name: Daniel Plath Letter ID: 0188 Commenter Or g anization: NiSource, Inc. Comment ID: 25232contradictory, NiSource's observation is that firmly addres sing those few real risks will ultimately pay significant dividends by preventing a few "bad"
p rojects from being developed that ultimately lead to an avoidable incident that taints the entire industry. These issues are addressed below.

Response: The Agency believes that the Class VI require ments balance site-speci fic flexibility with USDW protection. Rather than se tting performance or technology- b ased standards for GS projects, EPAis adopting a flexible approach, where operators of GS projects would develop and implement sitespecific plans for delineating the AoR, testing a nd monitoring the site, performing corrective action, and
p ost-injection site care. EPA believes that the pl ans—which would be reviewed and approved by the Director and periodically updated throughout the li fe of the project—pr omote an ongoing dialogue between the operator and the Director that will encourage use of the most appropriate technologies for a
p articular project.

Other EPA Comment Codes and Descriptions: 1210 1.1.1 Comments about the proposed rule Comment: Issue 2. Under the proposed rule, full-s cale implementation can begin after finalization.

The EPA is encouraged to consider limi ting the scale of projects initially in order to identify issues that may crop up that are currently unanticipated. The early large scale projects should be extens ively monitored in order to validate concepts that can be applied to other lo cations. This early work should include validation of appropriate modeling techniques capable of reliably predicting system responses. This early proof of con cept work should also address issues of heterogeneity in reservoi r and confining zones.

Response: EPA clarifies that the intent of the GS rule is not to set or control the pace at which GS is deployed. Rather, the purpose of the GS regulation is to ensure that GS, where deployed, is conducted in a manner that protects USDWs from endangerment. The Class VI GS requirements are one way in which the Agency can achieve this goal. EPA does not intend to limit the scale of initial GS projects; each project will be eval uated based on site-specific informati on about the ability of the geologic formations to safely receive and confine injected CO2. However, the Agency agrees that a protective initial approach is appropriate and additional safegua rds are necessary, given the uncertainty associated with the long-term effects of CO2 GS. EPA plans, ev ery six years, to collect and review data on GS
p rojects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: On behalf of our members, WORC urges EP A to establish as its highest priority the safety and effectiveness of the Carbon Dioxide Geologic Sequestration Wells
p rogram. We are very concerned that EPA is moving forward with a regulatory
p rogram for a technology that has yet to be demonstrated to be technologically and commercially viable on a large scale. It is possible that the first generation of geologic sequestration site s will experience a variety of
p roblems, as demonstrated b y the FutureGen pro j ect, in which unanticipated Commenter Name: And y Horn Letter ID: 0196 Commenter Or g anization: Colorado Ground Water Association (CGWA) Comment ID: 23922

Commenter Name: Rand y Joseph Letter ID: 0240 Commenter Or g anization: Western Organization of Resource Councils Comment ID: 23217technological challenges a nd budget overruns caused the Department of Energy to abandon the project.

Taking into account the potential challenge s of this technology that is not yet
p roven at scale, especially the unique chal lenges that the wester n US faces, we
p ropose instead of going forward with la rge-scale implementation of technology that is yet unproven and untested, that EP A focus intently on the research and design aspect at a limited number of pilo t sites to ensure that carbon capture and storage of CO2 is appropriate.

If EPA does go forward with its regulations, we urge you to use extreme caution and establish requirements that are as st ringent as necessary, even though those requirements are likely to be more expensive than other parts of the UIC
p rogram.

Our primary concerns are as follows: 1) protecting water supplies from contamination 2) ensuring that geologic sequestration projects are safely sited, 3) protecting the interests of landowners.

Response: EPA clarifies that the intent of the GS rule is not to set or control the pace at which GS is deployed. Rather, the purpose of the GS regulation is to ensure that GS, where deployed, is conducted in a manner that protects USDWs from endangerment. The Class VI GS requirements are one way in which the Agency can achieve this goal. EPA does not intend to limit the scale of initial GS projects; each project will be eval uated based on site-specific informati on about the ability of the geologic formations to safely receive and confine injected CO2. However, the Agency agrees that a protective initial approach is appropriate and additional safegua rds are necessary, given the uncertainty associated with the long-term effects of CO2 GS. EPA plans, ev ery six years, to collect and review data on GS
p rojects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Other EPA Comment Codes and Descriptions: 1614 1.3.1.2 Impurities in captured CO2; purity standards for CO2 Comment: We do not want to contaminate our groundwat er with those carcinogens. The fact is that CCWs, this is a significant issue in that each year our power plants
p roduce enough of this stuff to fill a train of coal car s that stretches from Manhattan to Los Angeles not just once, not just twice, but three and a half times. It is a huge problem and the EPA has pointed out that these toxins are carcinogenic and EPA has also stated that there are no regulations for these toxins. Therefore I urge the EPA when you are considering these regulations on CO2 sequestration that you broaden them to include CCWs. Stricter rules will not set us back economically, but rather it is going to ensure that the next generation has a prosperity to gr ow like our generation has.

Response: It is beyond the scope of the GS rule and th e UIC Program’s authority to require or set standards for upstream management of coal combus tion wastes (CCWs), also known as coal combustion residuals (CCRs). The UIC program’s authority under the SDWA is limited to ensuring that GS projects are sited, constructed, operated, and closed in a manner that protects USDWs. EPA is separatel y Commenter Name: Barbara Massone r Letter ID: 0531 Commenter Or g anization: Legacy Economy Comment ID: 21444considering standards for the management of CCRs under RCRA. See 75 Fed. Reg. 35128 (proposed rule).

Comment Code: 1270 1.1.2 Comments on other rules/issues



### Individual Comments

Comment: A plethora of regulations affect the deli very of power using coal. We suggest that the Agency consider other regulations addressing the environment, human health and safety, and electricity cost and reliability, when drafting and implementing these regulati ons. The Alliance urges the Agency to consider the support of integrated energy, climate, and environmental policy as time
p rogresses.

Response: EPA agrees that a strong regulat ory framework will be importa nt to ensuring that GS is deployed safely. The Class VI GS regulation will pr ovide certainty, consistency, and transparency to owners or operators and the public about requirements that apply to GS injection across the U.S. The Class VI GS regulation builds upon the long-standing, protective fra mework of the UIC program, which has been regulating the injection of billions of gallons of liquids for decades. The Class VI GS regulation enhances this existing fram ework with requirements for Class VI wells that are tailored to the unique nature of large scale GS of CO2. These additional protective re quirements include more extensive geologic testing, detailed computational modeli ng of the AoR and pe riodic re-evaluations, detailed requirements for monitoring and tracking th e CO2 plume and pressure front, and extended postinjection monitoring and site care.

In response to the suggestion that the Agency devel op an integrated permitti ng process, EPA clarifies that the UIC program’s authorit y under SDWA is focused on ensu ring consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: Climate change, drought, and the depletion of traditional ground water supplies due to population growth and land developm ent are causing drinking water utility managers to look at new sources of dri nking water that have not traditionally been considered as source s of drinking water. Coupled with improvements in desalination and other trea tment technologies, drinking water sources of high salinity are being used for water suppl y. AMWA recommends that EPA reexamine the current classification of a USDW (i.e ., an aquifer with a total dissolved solids (TDS) concentration of less than 10,000 mg/L) when siting Class VI geosequestration wells. The potential need to use saline aquifers for potable supply, particularly in water-stressed areas, should take precedence over the sequestration of carbon dioxide there. Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23794

Commenter Name: Diane VanDe Hei Letter ID: 0213 Commenter Or g anization: Association of Metropolitan Water Agencies (AMWA) Comment ID: 22922Response: EPA clarifies that addressing climate change , drought, and the deplet ion of traditional ground water supplies are outside the scope of the Cl ass VI GS rulemaking. Rather, the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provi de requirements to prevent endange rment of USDWs in anticipation o f the eventual use of GS to reduce CO2 emissions.

The Agency acknowledges commenter concerns about water resources and future water resource availability. However, modifying th e definition of a USDW is outsid e the scope of the Class VI GS rulemaking. USDWs are defined as aqui fers currently being used as s ources of drinking water or those capable of supplying a public water system and have a total dissolved solids (TDS) content of 10,000 milligrams per liter or less (§144.3).

The primary goal of the UIC program under the SDWA is to protect USDWs in order to ensure a reliable supply of drinking water fo r the American public. The Class VI GS rule, as part of the UIC
p rogram regulations, continues th e program’s tradition of ensuri ng the protection of USDWs. The
p ermitting, siting, construction, opera tion, monitoring, and post-injection site care requirements in the GS rule build on a long-standing prot ective regulatory fram ework, tailored to the unique characteristics of CO2 injected for the purpose of GS.

Comment: - Relationships with other Environmenta l Laws: The Agency should carefully consider any discussion of other environm ental laws that it may desire to include in the Preamble to the rules in order to ensure that such discussion is necessary and does not hamper the suc cessful commercialization ofCCS.

Response: EPA clarifies that the Class VI GS regulation is being promulgated under authority of the Safe Drinking Water Act, and othe r environmental laws are outside the scope of the Class VI GS rulemaking. The purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in antici pation of the eventual use of GS to reduce CO2 emissions.

In a separate rulemaking under authority of the Clean Air Act (CAA), EPA is amending the Greenhouse Gas Reporting Program at 40 CFR Pa rt 98 to add reporting requirement s for CO2 injection and GS. The greenhouse gas mandatory reporting requirements build on the Class VI requirements outlined in this final rule with the additional goal s of verifying the amount of CO2 sequestered and collecting data on any CO2 emissions to the su rface from GS facilities.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CC S related issues to minimize redundanc y and maximize efficiencies Commenter Name: Michael Moore Letter ID: 0265 Commenter Or g anization: North American Carbon Capture & Storage Association (NACCSA) Comment ID: 22858for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

Other EPA Comment Codes and Descriptions: 4300 2.4.4 Injection Depth Comment: And then secondly, I would like to agree with American Waterworks Association about the point that changi ng technical abilities for cleaning up water as well as increasing water demand does make it important that we not consider ten thousand parts per million to be set in stone.

Response: EPA recognizes that there is increasing de mand for water resources and that technology improvements may make high TDS aqui fers viable drinking water sources. EPA believes these potential resources should be considered when injection depth waivers are sought. Therefore, the final GS rule at §146.95(b) requires the Director to c onsider these issues in determining whether an injection depth waiver is appropriate. Specifically, the Director must consider whether alternative injection sites are available; community needs, demands, and supply from drinking water res ources; planned needs,
p otential and/or future use of USDWs and non-USDWs in the area; and a plan for securing alternative resources or treating USDW formation waters in th e event of contamination related to the Class VI injection activity.

EPA is not changing the USDW definition; changing the definition of a USDW is outside the scope of the GS rulemaking. The GS rule focuses on ensuring protection of USDWs, as required under the SDWA, by establishing regulations to ensure the sa fe injection of CO2 for long-term storage.

Other EPA Comment Codes and Descriptions: 1670 1.3.7 Other/miscellaneous risks Comment: The rule I believe, I believe the pream ble does mention the possibility of interference among projects, but whether or not that is the case, we think it is important that the rule contain a provisi on to head off potential interference among projects. The idea that seems to make sense to us is to flatly say that a
p roject cannot interfere with the effect iveness of a preexisting project and anytime there is an overlap in the pressu re fronts or footprint or however else you might define it, we think there ought to be inquiry made as to whether that would constitute interference. A rule like that would force projects in a single basin or brine formation to space them selves at least somewhat properly.

Response: EPA anticipates that the impacts of multiple operators inje cting into hydraulically connected formations will be accounted for in the initial Ao R calculation. EPA adds th at the owner or operator must demonstrate, in the proposed AoR and corrective ac tion plan, to the satisfaction of the Director that the modeled AoR will be based on detailed geologic data collected on the site and includes consideration of existing conditions such as the presence of multi ple operators. EPA adds that if any new GS projects are permitted within the AoR of a GS project be tween AoR evaluations, th e AoR reevaluation must address such projects. EPA also expe cts that the permitting of the newer GS project will have considered the presence of an ex isting GS project. Commenter Name: Scott Anderson Letter ID: 0520 Commenter Or g anization: Environmental Defense Fun d Comment ID: 21419

Commenter Name: Scott Anderson Letter ID: 0520 Commenter Or g anization: Environmental Defense Fun d Comment ID: 21429Comment: How about an EPA rule that goes like this. No use of any form of energy that does not yield more net energy across its pr ocess life cycle than it actually contains in its primary energy capture mo de. Short of that, I must call today

Response: The UIC program’s authority under the SDWA focuses on ensuring that Class VI GS
p rojects are permitted, sited, constructed, operated, monitored, and closed in a manner that protects USDWs from endangerment. Prohibiting the use of certain forms of energy is outside the scope of the Class VI GS rulemaking.

Comment: Does it make any sense at all to be expending more energy than coal actually yields and more money than could ever be justified with comprehensive life cycle accounting to widely used coal as a fuel source in the first place or by extension to perform carbon capture and sequestration? Does it net out to administer this stuff with hearings like this knowing what we already know? To accept as taxpayers the well known liabilities to fish a nd wildlife habitats and human health? To do the appropriate and necessary greenhouse gas reduction accounting? To deal with interstate boundary and commerce issues? To mine and
p rocess the coal with all the environmental degradation and health costs that we know are associated with that; to trans port it to its destinations and then spend the fuel and human resources and fuel again to send the trains back empty? To burn it, gasify it, liquify it, whatever and then spend more money and more energy trying to put CO2 back into the gr ound from whence it came in the first
p lace, for heaven's sake? And then, and then importantly trying to guess, guess how effective that process might be since we are lacki ng longitudinal data and I am wondering do reliable methods even exis t to monitor that th e sequestered CO2 is staying put? We are getting new informat ion that it is not staying put at least in a few cases, but even this non-sc ientist here knows that gasses have a tendency to seek the surface. I can see th at when I drink my 7-up that I like every afternoon. The bubbles like to go up and as many others here can attest to better than I, CO2 leakage at the surf ace can cause serious public health and safety issues so. And then of course, not to mention that we have been undoing the energy intents given costly sequestrati on exercise that we just gone through and oh by the way, reintroducing CO2 again above ground as a greenhouse gas. So I am asking you, does this make any sense at all to even be in the business of doing these activities?

Response: EPA clarifies that prohibiting the use of certain forms of energy, including coal and greenhouse gas accounting are outside the sc ope of the Class VI GS rulemaking.

EPA recognizes that GS poses unique challenges, su ch as buoyancy; for this reason, the requirements for GS wells are tailored to the unique nature of large scale GS of CO2. These additional protective requirements include more extensive geologic testi ng, detailed computational modeling of the AoR and
p eriodic re-evaluations, detailed requirements for monitoring and trac king the CO2 plume and pressure front, and extended post-injecti on monitoring and site care. Commenter Name: Beck y En g lish Letter ID: 0524 Commenter Or g anization: Sierra Club Comment ID: 21487

Commenter Name: Beck y En g lish Letter ID: 0524 Commenter Or g anization: Sierra Club Comment ID: 21488Comment Code: 1280 1.1.2.1 General comments on climate change/ global warming



### Individual Comments

Comment: The scientific basis for sequestering Car bon Dioxide (CO2) as a means of slowing or eliminating climate change (Globa l Warming) is not scientifically established. In fact, EPA in the proposed rule does not claim anthropogenic CO2 is the cause of global temperature increase. EPA simply infers sequestration is necessary, without support. Refer to th e Comment Section below entitled "Sequestration is not necessary" for deta ils on the lack of supporting data for this EPA inferred position.

Response: EPA clarifies that the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. Mitigating climate change is outside the scope of the Class VI GS rulemaking.

Comment: CS WELLS ARE NOT NECESSARY

Carbon dioxide sequestration will not stop global temper ature increase! EPA in the preamble to the CS proposed rule (73 FR 43496-43502) discusses the reasons for the need for CO2 sequestration. Nowhere in those pages does EPA state that carbon dioxide emissions cau se global warming or wh at the optimum earth temperature is, or how the Agency knows wh en the optimum temperature is reached, so future sequestration can be discontinued. Is EPA suggesting sequestration continue until it causes the next ice age? A review of th e U. S. Department of Energy (2007) report demonstrates a sim ilar lack of CO2 cau se and effect.

We can find no peer reviewed technical pape r, referenced by EPA or anyone else (not based on computer si mulation) showing CO2 caus es global warming. EPA relies heavily on computer simulations by the Intergovernmental Panel on Climate Changes (IPCC) reports. Reference to IP CC reports subjects EPA to serious question regarding the technical validity of the information presented. The use of the Hockey Stick Figure (Figure 22, IP CC, 1996) brings into sharp focus the
p olitical nature of the IPCC reports. McIntyre and McKitrick (2003) demonstrated conclusively the Hockey Stick Figure was based on truncated data, obsolete data, calculation errors and quality control deficiencies. Also, Figures 5.20 and 5.21 (IPCC, 2005) , sequestration well detail s, demonstrate IPCC is technically deficient because, IPCC blithely suggests pulling cemented casing from Class VI at the completion of injection, IPCC Figure 5.21. Experience demonstrates cemented casing cannot be pulled. IPCC (2005 at page 231) suggests milling the casing from the shoe upwards to remove corrodible metal from contact with the carbonic acid. Millin g is possible. Modern mills can "ho g out" 10 feet of Commenter Name: Geor g e Hollida y , PhD, PE, BCEE Letter ID: 0114 Commenter Or g anization: Hollida y Environmental Services, Inc. Comment ID: 22520

Commenter Name: Geor g e Hollida y , PhD, PE, BCEE Letter ID: 0114 Commenter Or g anization: Hollida y Environmental Services, Inc. Comment ID: 22527casing per hour, but the metal chips settle -out in the well Blowout Preventer,
p reventing proper operation in the event of an emergence. The ludicrous suggestion of using a milling stone as a means of connecting to a fixed packer defies all understanding, IPCC Figure 5.20. As tute scientists and engineers are very wary of IPCC reports, because of the frequent and consistent errors contained in the reports.

EPA, in the proposed sequestration rule, does not provide any indication of the benefit sequestration will pr ovide other than reduce CO2 concentration in the atmosphere. Even that goal appears questi onable. Our extensive review of the technical literature demonstrate no p eer reviewed reports based on field observations are available showing a direct relationship of global warming caused by increase in the at mospheric CO2. However, Lu cas, 2008, states the "We Can Solve It" (www.wecansolveit.org) campaign compares "your commitment to solving the climate crisis as [being equi valent to solving] the World War II, N ormandy landing, the civil rights moveme nt and putting a man on the moon" combined. Unfortunately, www.wecansolveit .org offers no supporting data, but it offers new high financial income opportunities, which appears to be the major driving force behind temperature change projects.

Is the relationship between CO2 and global temperature increase is real? The quantity of anthropogenic CO2 emissions are infinitesimally small compared with naturally occurring CO2 releases as s hown by DOE, Figure 1, below,. The U.S. Department of Energy ( www.fossil.energy.gov/program s/sequestration/overview.html ) developed the graph, showing projected CO2 entering the atmo sphere during 2008 from Anthropogenic sources is 6.0 GtC/yr: Forests and Soil s release >100 GtC/yr: Geologic >300 GtC/yr and Oceans 1,400 GtC/yr. It a ppears sequestering all of the anthropogenic CO2 in minuscule when compared with natural sources. Will sequestering such a small quantity effective reduce gl obal warming?

[Figure 1. 2008 Estimated United States CO2 Emissions for 2008. See pdf]

IPCC, 1996. Second Assessm ent Report, Summary for Policymakers.

Lucas, F., 2008. Cashing in on Climate Ch ange. Human Events, 64:28;15, August 14, 2008

McIntyre, S. and R.M. McKitrick, 2003. "Correction of Mann et al. Proxy Data Base and Northern Hemisphere Average Surf ace Air Temperature Series" Energy and Environment, 14:751-771

U.S. Department of Energy, 2007. Car bon Sequestration Technology Roadmap and Program Plan 2007. http://www.netl.doe.gov/technologies/carbon_s eq/refshelf/project%20portfolio/20 07/2007Roadmap.pdf

Response: EPA clarifies that the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in an ticipation of the eventual use of GS to reduce CO2 emissions. As described above, mitigating climat e change is outside the scope of the Class VI GS rulemaking.Comment: SEQUESTRATION IS NOT NECESSARY

Based on a review of existing technical papers, CO2 emissions are not causing climate temperature change. There have been climate changes for at about 2 million years. Life has st ruggled forward under climat e temperature increases and decreases without being annihilated.

During these temperature changes, Green land has gone from a marginal framing area to a bleak cold frozen area, but pe ople continue taking advantage of the warmer climate by moving away from the co ld areas. The belief that these global temperature changes can be mitigated by sequestering carbon dioxide has no scientific support, since previous Global temperature increases occurred in the absence of anthropogenic CO2.

Climate models, which are being used to suggest CO2 is causing global warming are inaccurate at best, because climate predictions are very complicated and beyond our current technical capabilities. Relying on computer modeling as the basis for needing the instant rule proposal is a cruel hoax.

Response: As described above, mitigating and modeling climate change is outside the scope of the Class VI GS rulemakin g. EPA clarifies that the purpose of the Clas s VI GS rule is to ensure consistency in permitting underground in jection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: A: CO2 SEQUESTRATION IS NOT NECE SSARY TO STOP GLOBAL WARMING

1. DOE compared the 2008 estimated CO2 emi ssions from anthropoge nic sources with naturally occurring emissi ons, Fig 1. Based on the gra ph data, it is difficult to believe sequester ing the anthropogenic releases will change anything. 2. The only accurate means of measuring the changing Global Temperature is via satellite. Since 2001 the satellite measur ements show a decrease of 0.1°C per year, while the CO2 continues to increase..

3. The IPPC computer simulation of clim ate change predicts an "Atmospheric Hotspot" layer about 10 Km above the earth’s surface as CO2 increases. Try as we have, the weather balloons have never recorded such a raise in temperature. This casts doubt on the validity of the IPPC Model and the need for CO2 sequestration.

Response: EPA notes that mitigating and m odeling climate change is outside the scope of the Class VI GS rulemaking. EPA clarifies that the purpose of the Class VI GS rule is to ensure consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endan g erment of USDWs in anticipation of the eventual use of GS to reduce Commenter Name: George Holliday, PhD, PE, BCEE Letter ID: 0114 Commenter Or g anization: Hollida y Environmental Services, Inc. Comment ID: 24116

Commenter Name: Geor g e Hollida y , PhD, PE, BCEE Letter ID: 0127 Commenter Or g anization: Hollida y Environmental Services, Inc. Comment ID: 23052CO2 emissions.

Comment: Action is needed to reduce greenhouse gas emissions

In 2007, the UN Intergovernmental Panel on Climate Change said warming of the climate system is unequivocal and direct ly linked to human activity, primarily the burning of fossil fuels. Global warming threatens America and the world with more frequent and more severe storms, ne w outbreaks of diseases and crop pests, and massive coastal flooding. Scientists have documented that Arctic sea ice is melting rapidly and the Western United States already may be in permanent drought. The climate crisis requires urgent action. To a void the worst effects, global greenhouse gas emissions must peak by 2015 and then start falling by at least 50% by 2050, compared to 1990 levels. Developed countries must reduce their greenhouse gas emissions by at le ast 25 percent below 1990 levels by 2020, and at least 80 percent below 1990 leve ls by 2050.[FN1 1 IPCC, 2007: Climate Change 2007: Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 996 pp.]

Coal is the largest emitter of global wa rming pollution in our country. In fact, emissions from coal-fired power plants are responsible for 40 percent of the global warming pollution in today’s atmo sphere.[FN2 2 U.S. Environmental Protection Agency, "Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005," April 2007. Based on calculation of CO2 emissions from tables 3-1 and 3-3.] Yet world governments are pla nning to build hundreds of coal power
p lants in the next decade. If such plan s go ahead it will be impossible for governments to reduce greenhouse gas emissions enough to seriously tackle climate change.

Response: EPA clarifies that mitigating climate change a nd regulating the use of coal are outside the scope of the Class VI GS rulemaking. The purpose of th e Class VI GS rule is to ensure consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions The requirements apply to owners or operators of wells th at will be used to inject CO2 into the subsurface for the purpose of long-term storage.

Comment: Greenpeace would urge the United States not to divert resources from proven solutions to climate change such as wi nd and solar power and energy efficiency to invest in ris ky technology such as CCS. However, should such plans be

Response: EPA clarifies that other climat e change mitigation technologies such as wind and solar power and energy efficiency, are not within the UIC progr am’s authority and outside the scope of this rulemaking. EPA emphasizes that the UIC program’s authority under the SDWA is focused on ensuring that Class VI CO2 in j ection pro j ects are permitted, site d, constructed, operated, monitored, and closed in Commenter Name: Emil y Rochon Letter ID: 0129 Commenter Or g anization: Greenpeace International Comment ID: 23060

Commenter Name: Emily Rochon Letter ID: 0129 Commenter Or g anization: Greenpeace International Comment ID: 23074a manner that protects USDWs from endangerment.

Comment: CCS and a 'Clean Energy Future': En courage public acceptance of CCS by emphasizing it as one part of a strategic national plan for effecting a 'Clean Energy Future'.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in these technologies is outside the scope of the Class VI GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, proj ects are permitted, sited, constructed, operated, and closed in a manner that protec ts USDWs from endangerment.

Comment: I. CCS and a 'Clean Energy Future'

Recommendation I: Encourage public acceptance of CCS by emphasizing it as one
p art of a strategic plan for effecting a Clean Energy Future'.

A prominent theme in public opposition to CCS is the concern that geologic storage will prolong our dependence on fo ssil fuels and divert the necessary funds for developing sustainable energy re sources in the US. In addition to
p roviding protocols for public outreach, education, and dialogue about geosequestration siting, the EPA has an opportunity during these early stages of implementation of national CCS policies to frame social perceptions of geologic storage as part of a larger set of st rategies for achieving a 'Clean Energy Future.' The Sierra Club strongly recomme nds that the EPA partner with the DOE and other federal agencies to garner publ ic support for CCS by characterizing it as one of several policy measures designe d to reduce the overabundance of CO2 in our atmosphere. While CO2 capture is outside the scope of these proposed regulations for CO2 injection and storage, it is important to recognize that many opponents of CCS in general are fearful that the development of CO2 capture technology will prolong our reliance on coal for elect rical generation, thus delaying deployment of re newable energy resources such as wind, solar, and geothermal. By promoting the adoption of "companion carbon control strategies" such as energy efficiency, energy conser vation, and renewable energy electrical generation, the EPA can help position CC S as one constituent of a broader integrated objective.

Response: EPA clarifies that the Class VI GS re g ulation does not promote or encoura g e the use of GS; Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Ener gy and Climate Chan g e Comment ID: 21598

Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Ener gy and Climate Chan g e Comment ID: 21619rather the purpose of the rule is to ensure consis tency in permitting underground injection of CO2 at GS operations across the United States and provide re quirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA agrees that GS is one technology in a portfolio of options , including energy conservation, effici ency improvements, and the use of alternative fuels and renewable energy sources, th at could be deployed to reduce CO2 emissions. However, the use of and investment in these technologies is outside the scope of the Class VI GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, projects are permitted, sited, constructed, operated, and cl osed in a manner that protects USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 1480 1.2.2.2.2 CO2 is not a pollutant Comment: J. CO2 as a Valuable Commodity

Recommendation J: Re-frame public perceptions of CO2 as a hazardous waste material by funding CCS demonstration projects which biol ogically or chemically transform CO2 into valuable products.

Localities that oppose the permitting of ge ologic sequestration pr ojects usually hold the perception that CO2 is a toxic wa ste material being dumped and buried in their backyards. Typical ly, localities are distrustful of the motivations of business and government representatives w ho seek to allay fears of economic, health, and environmental risks attendant to pumping CO2 into injection wells. An important avenue for re-framing such perceptions is by emphasizing CCS methods which value carbon dioxide as a na turally occurring and commercially valuable resource. The DOE's carbon sequest ration program at the National Energy Technology Laboratory includes funding for res earch and development of advanced chemical and biological a pproaches, including syst ems for decarbonization,
p hotosynthesis, and conversi on of CO2 into useful fo rms. However, since no demonstration projects have been anno unced over the same time period that multiple geosequestration projects have been implemented, the DOE's "Novel Carbon Sequestration Concepts" program a ppears to be under- publicized and under-funded. This lack of vigor in pr omoting carbon transformation methods gives the public the impression that CCS technologies are being readied solely for the purpose of perpetuating our depe ndency on fossil fuels for electricity generation and manufacturing processes.

N umerous business ventures are seeking opportunities to prove the efficacy of their carbon mineralization processes with larger demonstration projects. Companies holding proprietary patents for us eful CO2-sequestered materials such as calcium carbonate cement and cons truction materials, paper products, biodegradable plastics, and algae biofue ls need government funding and support to scale-up their methods. By narrowly targeting ge osequestration as the primary carbon storage solution, the federal govern ment is missing an opportunity to secure broader public acceptance of CCS as a safe and viable method for reducing the overabundance of CO2 in our atmosphere, and is ne g lectin g important avenues Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Ener gy and Climate Chan g e Comment ID: 21620for achieving that goal.

Response: EPA acknowledges that GS falls within the broader context of CCS and the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordina ted with other Agency program of fices and across federal agencies (e.g., with the Department of Energy; United St ates Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Minerals Management Service; and the Bureau of Land Management). The Agen cy continues to evaluate areas of potential applicability of other Federal environmental statutes including, but not limited to: the Clean Air Act; the Resource Conservation and Recovery Act; the Comprehens ive Environmental Res ponse, Compensation, and Liability Act; and the Marine Prot ection, Research and Sanctuaries Ac t to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize redundancy and maximize efficiencies for owners or operators . For additional information, please see the discussion entitled "How Does This Rulemaking Relate to Othe r Federal Authorities and GS and CCS Activities?" in the preamble to th e final GS rule.

EPA adds that the intent of the GS rule is not to promote GS. Rather, the purpose of the GS regulation is to assure that, where deployed, GS is conducted in a manner that protects USDWs from endangerment.

The Agency acknowledges that there is ongoing research in many fields that c ould address the broader environmental concern of climate change, but the focu s of the Class VI requireme nts is to ensure that, where GS is deployed, it is conducted in a manne r that protects USDWs from endangerment.

Much of the research on terres trial and geologic sequestration is being conducted by other federal agencies, particularly DOE's Of fice of Science and Technology (www.energy.gov/sciencetech/carbonse questration.htm). Other federal ag encies involved in research include the US Department of Agri culture, US Geological Survey, and others. EPA's Office of Research and Development is also researching issues rela ted to global climate change, including geologic and terrestrial se questration.

Comment: The rationale for regulating greenhouse gases, including CO2, is simple.

We don't know much for certain about this subject, but we do have a very good sense of the relative odds, and they are these :

If we do nothing about Global Warming and we are wrong, the consequences will be horrendous and in many cases irreversible.

In money terms, they will be much greate r than the money we would waste, if we were to do something and it turns out to have been unnecessary.

And by the way, why should we worry about a low probability of wasting money on the mitigation of Global Warming, when we happily wasted so much more on our "Iraq adventure" ? Why this sudden concern for "fiscal responsibility" when so much blood and treasure has been thrown aw ay for reasons which turned out to be entirely phony ?

[ We can be certain about that ! ] Commenter Name: Lewis L. Smith Letter ID: 0136 Comment ID: 21670Response: The Class VI GS requirements are designed to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in antici pation of the eventual use of GS to reduce CO2 emissions. For additional information on EPA's final regulatory approac h, please see the final rule and preamble as well as the rulemaking docket.

Comment: U.S. population. Our associations are very concerned with the effects of climate change on water resources a nd while we recognize the need for strategies to be developed that address mitigation of greenhouse gases (G HG), we also believe strongly that any strategy deployed for this purpose should above all else
p rotect our water resources.

Many of the most critical impacts of global climate change will manifest themselves through the hydrol ogic system, and there is already strong evidence that climate change is having an impact on the world’s water resources. In 2000, approximately 79% of 54,000 community water systems in the United States were supplied by groundwater (alm ost 86 million people). In addition, many surface water utilities are currentl y looking at conjunctive use and/or groundwater development as adaptation measures (supply portfolio diversification/new storage) to combat climate change. There is the potential for each of these utilities to be impacted by geologic car bon sequestration, simply by the fact that these utilities util ize groundwater resources.

Response: The Agency agrees that protecting drinking wa ter is important. The pr imary goal of the UIC
p rogram under the SDWA is to protect USDWs. The UIC program provides that no injection shall be authorized if it results in the movement of fluid containing any contaminant into USDWs, if the
p resence of that contaminant may cause a violation of any primary drinking water regulation under 40 CFR §141 or may adversely affect the health of persons (§144.12).

The GS rule, as part of the UIC program regulat ions, continues the Program ’s goal of ensuring the
p rotection of USDWs from endangerment. The purpose of the Class VI GS rule is to ensure consistency in permitting underground in jection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. The permitting, siti ng, construction, operation, monitoring, and post-injecti on site care requirements in the Class VI GS rule are built on a long-standing protectiv e regulatory framework, tailored to the unique aspects of CO2 GS.

Comment: AMWA appreciates the opportunity to comm ent on the proposed rule for permitting the geological sequestration of carbon dioxide (CO2). Ma ny of the most critical impacts of global climate change will ma nifest themselves through the hydrologic system, and there is already strong eviden ce that climate change is having an impact on the worl d ’s water resources. AMWA reco g nizes the importance of Commenter Name: Diane VanDe Hei Letter ID: 0206 Commenter Or g anization: Association of Metropolitan Water Agencies (AMWA) Comment ID: 22205

Commenter Name: Diane VanDe Hei Letter ID: 0213 Commenter Or g anization: Association of Metropolitan Water Agencies (AMWA) Comment ID: 22915reducing carbon dioxide emissions to mitigate climate cha nge impacts. Our member utilities across the country are engaged in efforts to reduce their carbon footprint and greenhouse gas emissions in a myriad of ways -- from increased efficiency to green power projects. However, protecting our nation’s water

Response: The use of and investment in climate change mitigation technol ogies is outside the scope of the Class VI GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, projects are permitted, sited, constructed, operated, and closed in a manner that protects USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 6000 3. Cost of the Proposed Rule Comment: We are also concerned that certain unnece ssary and costly requirements in the Proposed Rule would discourage, or even foreclose, the conversion of existing Class II EOR wells to Class VI geologic sequestration wells. This would undercut the effectiveness of the Proposed Rule’s provisions for such conversion. Unnecessary or unduly costly requirements would preclude CCS from playing the role that many policy analysts and govern ments worldwide believe that it must
p lay in any successful strategy for reduci ng atmospheric concentrations of CO2. This is important because it means that the EPA may - and indeed, must - balance objectives that pull at times in competing directions. In other words, if the EPA’s primary objective is to reduce CO2 emissions and if CCS is an essential component of a CO2 reduction strategy, th en the rules governing CO2 injection and storage must be crafted in such a way as to advance the primary objective of reducing GHG emissions.

N ew rules for CO2 sequestration that are t oo risky or too costly for widespread use will work against this primary overa ll objective of reducing GHG emissions. Absent a broader legal foundation than th e SDWA alone, however, the EPA could conceivably find itself required to im pose conditions for sequestration that would foreclose (or unduly limi t) the use of CCS as an emissions reduction tool. This, we fear, could defeat the very pur pose of the rule in the first place. Accordingly, we suggest that EPA examine whether it may be appropriate to invoke other existing statutory authorities as pa rt of the legal foundation for the new sequestration rules.

Response: EPA disagrees that certain requi rements for the conversion of ex isting Class II EOR wells to Class VI wells are unnecessary. The final GS regulation requires at §146.81(c) that owners or operators seeking to grandfather existing Cl ass II wells for GS demonstrate that grandfathered wells were engineered and constructed to m eet the requirements at §146.86(a) and ensure protection of USDWs, in lieu of requirements at §§146.86(b) and 146.87(a). These requirements do not impose additional stringency on conversion from Cla ss II wells as compared to new construction. For additional information on EPA's final regulator y approach, including transitioning of EOR wells for GS, please see the final rule and preamble.

In regard to cost, the Agency clarifies that sequest ration costs are expected to be a small component of total CCS project costs. EPA estimates that the GS rule requirements amount to approximately two
p ercent of the total CCS project costs, according to the cost analysis for the final GS rule, which is in the rulemakin g docket. EPA adds that promotin g or incentivizin g GS is outside the scope of the GS Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24275rulemaking. Rather, the purpose of the GS regulation is to ensure that GS is conducted in a manner that
p rotects USDWs from endangerment.

EPA is developing guidance on transi tioning of EOR projects. This guida nce will be available on EPA’s website at http://water.epa.gov/type/gr oundwater/uic/wells_s equestration.cfm.

Comment: We agree with EPA that CCS could play an important role in allowing deep greenhouse gas emission reductions from electric generation and industrial facilities. In order to achieve the cuts necessary to avoid the worst consequences of climate cha nge, CCS must be integrated within a larger climate
p olicy that includes legislation limiting greenhouse gas emissions, investment in efficiency improvements and renewable energy sources such as solar, wind, biomass and geothermal. [FN1]

[FN1: 1 IPCC Special Report on Carbon Dioxide Capture and Storage, 2005 (hereinafter "IPCC CCS") Section 1.1, 1.3.]

CCS must be deployed on a very large-scal e to enable deep cuts in worldwide greenhouse gases. To deploy this nascent technology in a short timeframe, it must be managed very proficiently from the start to minimize ecological, human health, and financial risks. Any CCS re gulatory regime must establish clear incentives for responsible site select ion, appropriate monitoring, safe and environmentally sound operation, and fi nancially responsible closure.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in these technologies is outside the scope of the Class VI GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, proj ects are permitted, sited, constructed, operated, and closed in a manner that protec ts USDWs from endangerment.

The GS regulation builds upon the long-standing protective framework of the UIC program, which has been regulating the injection of bi llions of gallons of liquids for decades. The Class VI GS regulation enhances this existing framework with requirements fo r Class VI wells that are tailored to the unique nature of large scale GS of CO 2. These additional protective requi rements include more extensive geologic testing, detailed computat ional modeling of the AoR and periodic re-evaluations, detailed requirements for monitoring and track ing the CO2 plume and pressure fr ont, and extended post-injection monitoring and site care.

Comment: The planet’s climate is changing fast. Greenhouse gas emissions from the use of fossil fuels, mainly carbon dioxide (CO2 ), are having a profound effect on our climate, presenting us with one of the most significant environmental and social challenges of the century. In its most r ecent Assessment Report last year, the Intergovernmental Panel on Climate Change, an independent scientific body, issued the loudest warnin g to date, callin g the warmin g in the climate s y stem Commenter Name: Kristin Henr y Letter ID: 0242 Commenter Or g anization: Sierra Environmental Law Program, Sierra Club Comment ID: 23307

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22269"unequivocal" and calling for serious emis sion reductions if we are to avoid truly dangerous greenhouse ga s concentrations. Failur e to pursue significant reductions in greenhouse gas emissions very s oon will make it much harder in the future both to stabilize atmospheric pollu tion concentrations and to avoid the worst impacts of climate ch ange. Climate change is e xpected to and, indeed, already is having a profound ef fect on sources of drinki ng water. The American West, for example, is already becoming noticeable hotter and drier, as a recent compilation of studies by the Rocky Mount ain Climate Organizat ion (RMCO) and N RDC summarizes.[FN1]

[FN1: 1 "Hotter and Drier: The West’s Ch anges Climate". Rocky Mountain Climate Organization (RMCO) and the Natural Resources Defense Council. Available at: http://www.nrdc.org/globalW arming/west/west.pdf]

A growing body of scientific research indi cates that we face extreme dangers to human health, economic well-being, and th e ecosystems on which we depend if global average temperatures are allowed to increase by more than 2 degrees Fahrenheit from today’s levels. We have good prospects of staying below this temperature increase if atmospheric concentrations of CO 2 and other global warming gases are kept from exceedi ng 350 to 450 parts per million (ppm) CO2equivalent. Achieving this goal will require rapid reductions in existing emissions, including action to cut emi ssions by approximately 80% by midcentury. This goal is ambitious, but ac hievable. It can be done through an annual rate of emissions reductions that ramps up to about a 4% reduction per year. Fortunately, a wide variety of tools is available today to achieve those reductions.

Response: GS is one technology in a portfolio of opti ons, including energy conservation, efficiency improvements, and the use of alternative fuels and re newable energy sources, that could be deployed to reduce CO2 emissions. However, the use and promotion of these technologi es is outside the scope of the Class VI GS rulemaking. The Class VI GS requirements are desi gned to ensure that, where GS is deployed, projects are permitted, sited, constructed, operated, and closed in a manner that protects USDWs from endangerment.

Comment: In comments on the Agency’s recent advanced notice of proposed rulemaking on using the Clean Air Act to combat climat e change, a coalition of environmental N GOs, including some members of our Envi ronmental NGO Group, pointed out that for the U.S. to achieve its necessary climate goals, contro lling CO2 emissions from new and existing sources of CO2 is required. That nece ssitates reductions from all sectors, including radical shif ts to zero-emitting technologies and corrective action on existing sources. Thes e reductions will require targeted measures and policies, which include air regulations that would set CO2 emissions standards implicating the captur e and sequestration of CO2. Setting an N SPS or a BACT standard based on CO2 capture technology necessarily creates a need for complementary re quirements to assure that the captured CO2 is effectively isolated from the atmosphere. At this time, such an outcome requires injecting CO2 underground for permanent sequestration in either hydrocarbon reservoirs or deep saline formati ons. Such permanent sequestration clearl y meets Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22274the definition of underground injection, regulated by the UIC program of the Safe Drinking Water Ac t ("SDWA").[FN6]

[FN6: 6 42 U.S.C. §300h, et seq. Geologic se questration of CO2 cl early meets the definition of underground injection found at 42 U.S.C. §300h(d)(1), "the subsurface emplacement of fluids by well injection." Carbon dioxide, whether injected in a supercritical state, or as a gas, meets the definition of a fluid included in the existing re gulations under the SDWA: those rules state that a "fluid" is "any material or substance which flows or moves whether in a semisolid, liquid, sludge, gas or othe r form or state." 40 CFR § 144.3.]

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in these technologies is outside the scope of the Class VI GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, proj ects are permitted, sited, constructed, operated, and closed in a manner that protec ts USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 1320 1.1.3 General comments about GS Comment: Assessment of the Proposed Rule The proposed rule repeatedly re ferences climate change mitigation by the inj ection of CO2 as the justification for the need for the new class of injection well:

Summary: "EPA is proposin g Federal requirements under the Safe Drinking Water Act (SDWA) for underground injection of ca rbon dioxide (CO2) for the purpose of geologic sequestration (GS). GS is one of a portfolio of options that could be deployed to reduce CO2 emissions to the atmo sphere and help to mitigate climate change."

And "If finalized, this proposal would he lp ensure consistency in permitting underground injection of CO2 at GS opera tions across the U.S. and provide requirements to prevent endangerment of US DWs in anticipation of the eventual use of GS to reduce CO2 emissions."

In Part II "What is the EPA Propos ing" the proposition reiterates:

"In addition to protecting USDWs, today’s proposed ru le provides a regulatory framework to promote consistent approach es to permitting GS projects across the U.S. and supports the development of a key climate change mitigation technology."

Under Part II A. "Why Is EPA Proposing To Develop New Regulations To Address GS of CO2?" Part II. Section 2, states: Th e Intergovernmental Panel on Climate Change (IPCC) has concluded that much of the warming in recent decades is very likely the result of human activities (IPCC, 2007). The burning of fossil fuels (e.g., from coalfired electric plants and other sources in the electricity and industrial sectors) is a major contri butor to humaninduced greenhouse gas emissions. Commenter Name: Mar y Munn Letter ID: 0273 Commenter Or g anization: Fond du Lac Reservation Comment ID: 24082Fossil fuels are expected to remain the ma instay of energy production well into the 21st century, and increase d concentrations of CO2 ar e expected unless energy
p roducers reduce the CO2 emissions to the at mosphere. The capture and storage of CO2 would enable the continued use of coal in a manner that greatly reduces the associated CO2 emissions while other safe and affordable alternative energy sources are developed in the coming decade s. Given the United States’ abundant coal resources and reliance on coal fo r power generation, CCS could be a key mitigation technology for achieving domestic emissions reductions"

And:

"Congressional climate change legislative proposals (the McCain-Lieberman bill S. 280, the Bingaman-Specter bill S. 1766, and the Lieber man-Warner bill S. 2191) indicate that CCS has th e potential to play a signi ficant role in climate change mitigation scenarios."

And:

"Today’s proposal provides a regulatory frame work to protect USDWs as this key climate mitigation technology is developed and deployed."

The allusion of mitigating climate change or reducing CO2 emissions by geologic sequestration cannot be fairly used as pe rsuasive point for this rule without
p roviding data demonstrating the mass balance of energy and carbon dioxide in the whole system. A great d eal of analysis has been completed and posted on the docket of cost and incremental cost within the proposed rule for CCS and GS implementation but no analysis is made in terms of the actual amount carbon dioxide that will be sequestered in relation to the amount of carbon dioxide emitted throughout the process (Cost: EPA-HQ-OW-2008-0390- 0073 and EPA-HQOW-2008-0390-0094).

A mass balance of the participating foss il energy processes, generating the CO2, must be evaluated to determine if any real reduction in CO2 can be made. CO2 is emitted during the excavation and transport of the fossil fuel to a power plant. Additional power will be re quired, and will emit additional CO2, to provide the energy to extract the CO2 from the emissi on stream, to compress, transport, and to inject the CO2 into a geologic formation.

Response: EPA clarifies that the Class VI GS requirements are designed to ensure consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. The requirements apply to owners or operators of inject ion wells used to inject CO2 for
p ermanent storage.

GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in thes e technologies is outside the scope of the Class VI GS rulemaking. The Class VI GS requirements are designed to ensu re that, where GS is deployed,
p rojects are permitted, sited, constructed, operated, a nd closed in a manner that protects USDWs from endangerment.Comment: Social Justice: The United Nations E nvironmental Progamme states: "Globally around $300 billion or 0.7 per cent of global GDP is being spent on energy subsidies annually. The lion's share is be ing used to artificially lower or reduce the real price of fuels like oil, coal and gas or electricity generated from such fossil fuels. Cancelling th ese subsidies might reduce greenhouse gas emissions by as much as six per cent a year while contributing 0.1 per cent to global GDP."

Mr. Steiner added: "Whereas fossil fuel subsidies are an example of a blunt
p olicy instrument, perpetuating old and in efficient economic models, the CDM is an example of a more intelligent, market-based mechanism that is fostering the transition to a modern Green Ec onomy". (Accessed online Nov. 14, 2008 http://www.unep.org/Documents. Multilingual/Default.asp?Do cumentID=543&ArticleID= 5902 )

Response: EPA clarifies that the Class VI GS requirements are designed to ensure consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. The requirements apply to owners or operators of inject ion wells used to inject CO2 for
p ermanent storage. Fuel subsid ies are outside the scope of the Class VI GS rulemaking.

Comment: Although the effort made to address the serious issues of climate mitigation through CCS is greatly appreciated, the effo rt largely appears to mitigate CO2 emissions via a complex system that wi ll, in reality, increase fossil energy consumption. With projected consumption to increase more than 30% by 2030 and CCS adding at least 20% additional demand, one may wonder if this proposal equates to yet another subsidy for fossil fuel industry.

The absence of analysis of the carbon neutrality of this project is a serious omission. An analysis of this kind should have been the first step in evaluating this proposal, yet it is not addressed in the rule or in any of the supporting documentation. An endeavor of this ma gnitude should be demonstrably carbon neutral and hopefully operate as a true carbon sink.

Response: As described above, EPA clarifies that the purpose of the Class VI GS requirements are designed to ensure consistency in permitting underground in jection of CO2 at GS operations across the United States and provide require ments to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. The requirements apply to owners or operators of injection wells used to inject CO2 for permanent storage. Th e topics of climate change mitigation, fossil energy consumption, carbon neutrality, CO2 emissions, and GHG regulations are outside the scope of the Class VI GS rulemaking. Commenter Name: Mary Munn Letter ID: 0273 Commenter Or g anization: Fond du Lac Reservation Comment ID: 24085

Commenter Name: Mar y Munn Letter ID: 0273 Commenter Or g anization: Fond du Lac Reservation Comment ID: 24090

Commenter Name: Mar y Munn Letter ID: 0273Comment: This rule is written for the existing energy production system. The reliance on fossil energy must change to meet the ch allenge of climate change. Barriers to the success of alternate sources of energy must be removed so the issue can be faced head on. This rule will impede a nd obstruct progress for those competing industries.

The resources required to pursu e this undertaking will be in direct competition with efforts focused on sustainable energy sources and alternative, arguably more effective carbon sequestration, utilizing wetland restoration, improved agricultural methods, and sustainable fore stry practices that have numerous and vital fringe benefits.

Experts in carbon sequestration know that utilizing biologic methods of carbon capture is cost effective and will in clude economic benefits. For example, wetland protection and restoration will not only sequester carbon but will
p urify water, impede drainage (flooding) , and replenish aquifers. Many avenues could be used to reverse engineer the activities that drained these wetlands. Many studies including the K yoto Protocol Wetland Restor ation and Management and the Wilderness Society Forest Carbon Re port support these alternative carbon sequestration mechanisms.

Reduction of carbon emissions to the atmos phere is the primary driver for this new class of well, proof that carbon capture and sequestration will provide a net removal of CO2 must be provided else any reference to the reduction of CO2 emissions or climate mitigation must be removed from the document.

Response: EPA agrees that GS is a key cl imate change mitigation technology that is part of a portfolio of options that could be deployed to reduce CO2 emissions. Other options include efficiency improvements and the use of alternative fuels and renewable energy sources. However, promoting or incentivizing these technologies is outside the UIC program’s author ity under the SDWA, which focuses on ensuring that, where deployed, GS projects are permitted, sited, constructed, operated, monitored, and closed in a manner that protects USDWs from endangerment.

Other federal agencies (e.g., DOE and the U.S. Geological Survey) have conducted research on available storage capacity and made determinations of the feasibility of capturi ng and storing CO2 at the scales needed to address climate change. These agencies, along with pr ivate entities, have identified large areas for potential sequestration in capacity studies. For example, in 2008, USGS initiated development of a methodology for estimating the capacity to store CO2 in geologic formations of the United States. In 2009, USGS published a propos ed, risk-based methodology for GS capacity estimation. This report, Development of a Probabilistic Assessment Met hodology for Evaluation of Carbon Dioxide Storage, is available at http://pubs.usgs.gov/of/2009/1035/ofr2009-1035.pdf.

Comment: This isn't about me, and it isn't about you, it's about global climate change. That's why we're here, that's why anybody's contemplating geological sequestration.

Just this week in the current issue of Science Ma g azine, Peter Cox and Chris Commenter Or g anization: Fond du Lac Reservation Comment ID: 24092

Commenter Name: Mark Sin g e r Letter ID: 0504 Commenter Or g anization: Green America Pro j ect, LLC Comment ID: 21242Jones report research that gives more ba d news. New data shows that, this is the, the current issue, new data shows that climates sensitivity of the carbon cycle is now constrained at the high end of the range of values consistent with contemporary records.

Previous studies gave a broad range of po ssible values from relatively minor to alarming. Cox and Jones now constrain it to the high end. If you read the article, it's written in a very dry, emotionless tone. But in a personal communication Peter Cox my question, which was, you know, is this good news or bad news, it is bad news for the world, but its bad news that we have to hear.

Response: EPA clarifies that climate change mitigation is outside the scope of the GS rulemaking. Rather, the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: I recognize that the Suprem e Court of the United States has given the EPA the regulatory authority to regul ate CO2. Over the past eighteen months, I have come to the conclusion that managed production of CO2 is not the cause of global climate change.

Dr. Roy Spencer of the University of Al abama has written a book called Climate Confusion. In this book he st ates that man's production of CO2 is equivalent to one molecule of CO2 for every 100,000 molecu les of the atmosphere over a five year period. So when we hear these numbers of millions and millions of tons of CO2 being released in the at mosphere, we must put that in context of what part of that is generated by man. Dr. Spencer thinks that this is not a significant contribution to global warming.

I have also read numerous articles, five different books, consu lted with several PhD. Climatologists, in particular, Dr. William Gray from Colorado State University who is known for his annual fore cast of hurricane activity. All of the literature that I have read further indicate that man's production of CO2 is not the cause of climate change.

The issue of CO2 causing climate change is not a closed issue as some would have you believe.

I would refer you to a project called the Petition Project written by the Oregon Institute of Science and Medicine wh ere over 31,000 scientists have signed a
p etition to the President of the United St ates of America saying to take drastic action with respect to eliminating mass production of CO2 will not do anything to minimize climate change.

So, I respect the EPA for its efforts and attempts to do something to comply with the mandate by the U.S. Supreme Cour t and to also respond to the apparent
p ublic concern of climate change by ma n. However, as we go forward the development of these re g ulations, both the re g ulation of drinkin g water qualit y Commenter Name: Dave Bufalo Letter ID: 0522 Comment ID: 21468and atmospheric relationship to, I would urge the EPA to look closely at the cost benefit ratios of what this is going to cost.

Response: EPA clarifies that climate change mitigation is outside the scope of the Class VI GS rulemaking. Rather, the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

EPA clarifies that the Class VI GS requirements apply to owners or opera tors of injection wells used to inject CO2 for permanent storage. The Class VI GS rulemaking is promul gated under Safe Drinking Water Act authority and does not relate to any e ndangerment and cause or c ontribute findings under the Clean Air Act. The Class VI GS requirements do not depend upon, and are unaffected by, Clean Air Act endangerment and cause or contri bute findings. More information on EPA's Endangerment and Cause or Contribute Findings for Greenhouse Gases under Secti on 202(a) of the Clean Air Act can be found at http://www.epa.gov/climatech ange/endangerment.html.

Other EPA Comment Codes and Descriptions: 5520 2.10.1 Appropriateness of existing public
p articipation requirements (P art 25 and Part 124) for GS (seeking comment) Comment: Modeling data should have been provided well before the beginning of this thirty day period, this comment period. Again, we need more time.

I also want to point out that a remediat ion plan should have been developed by now to deal with all possible contamin ation events in tandem with this
p articular process especially in view of EPA's, some of EPA's past failures to
p erform adequate risk monitoring and ti mely detection of remediation of contamination. Obviously, a remediation pl an needs to be in place along with this particular proposal. Pleas e provide us with that re mediation plan and give the public time to comment on that as well.

EPA's management of carbon capture a nd sequestration operations should be absolutely transparent to the public and so today, I want to call for real time online postings and RSS feeds of all incide nts no matter how minor to interested members of the public. EPA should be provi ding such reporting for all incidents already and not just for carbon sequestrati on leaks, but for really I think all incidents across y our entire realm of responsibility. Again, with the transparency, the public needs to know what is going on a lot easier than it currently is for us to find things out.

I am not a geologist or a mining engineer , but I think I have some common sense and as a U.S. citizen, I just must insist that EPA adopt a more comprehensive method for evaluating IGCC and carbon sequestration, carbon capture and sequestration in view of the now well known fact that carbon based fuels are roasting our atmosphere and rapidly re ducing the viability of our planet.

Response: EPA clarifies that the final rule does not cha nge the public notice requirements for injection well owners or operators already required under 40 CFR Part 124. However, because of the unique nature of GS projects, and the anti cipated level of public interest in GS projects, EPA encourages early
p ublic involvement in GS pro j ects. Providin g the public with accurate, pro j ect specific information in Commenter Name: Beck y En g lish Letter ID: 0524 Commenter Or g anization: Sierra Club Comment ID: 21484the early stages of each GS project can help clarify project details and avoid public misperceptions about the nature and safety of GS projects, and will allow a potential GS owner or operator and the permitting agency to address the public's concerns before the permitting process is complete.

EPA clarifies that the final GS rule requires each owner or operator to de velop an emergency and remedial response plan prior to receiving a permit to inject carbon dioxide. See §146.94. This plan must be submitted to the Director along with the permit application and wi ll be available for review during the public comment period for the draft permit. Each owner or operato r will be responsible for any remediation associated with his or her well. The rule also requires each owner or operator to maintain financial responsibility for emergency and re medial response. See §146.85( a). EPA is developing guidance on both financial responsibility and emergency and remedial response plans.

EPA agrees with commenters that the use of ne w forms of information te chnology can improve public
p articipation and understandi ng of GS projects and the associated injection technologies involved. EPA does not require the use of any new information tech nologies to inform the public, but encourages GS
p roject operators and permitting authorities to use the Internet as well as both new and established tools to explain and post information on th e latest developments. This info rmation may include schedules for hearings, briefings, and other opportunities for involvement. EPA plan s to conduct outreach on the GS rule, and provides GS related information on its website at http://water.epa.gov/type/groundwat er/uic/wells_sequest ration.cfm. EPA currently uses social networking applications for importa nt information (e.g., Facebook and Twitter), and will encourage GS operators and permitting authoritie s to use similar technologies to keep the public informed of GS
p rojects.

Comment: So I'd like to start with a note and say that this is not an attempt to legitimize or to further perpetuate the use of coal. We believe that there are much better, cheaper, and cleaner ways to meet our energy needs. Nonetheless, there is a very good reason why we do need to have CCS in the mitigation
p ortfolio as well and this is because of the world's vast coal resources, the
p rojected business as usual use of this resource and the pace at which we see climate change evolving. We believe that co al, mainly in China is and climatic changes are on a collision course and we really need to do something about it.

Response: EPA clarifies that the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. Regulating the use of coal or any energy form is out side the scope of the Class VI GS rulemaking. More information on EPA's Endangermen t and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act can be found at http://www.epa.gov/climatech ange/endangerment.html.

Comment Code: 1290 1.1.2.2 Comments that EPA should regulate CO2 as a pollutant



### Individual Comments Commenter Name: George Peridas Letter ID: 0534 Commenter Or g anization: Natural Resources Defense Council (NRDC) Comment ID: 21450Comment: Dear Administrator Johnson and EPA staff: I urge you to take immediate action and rule that carbon dioxide and othe r global warming pollutants clearly "endanger the public health and welfare" and thus should be regulated under the Clean Air Act. Carbon dioxide (CO2) pol lution is the primary cause of the climate crisis. We're already seeing dr amatic and dangerous climate effects today, and the climate crisis threatens th e very livability of our planet for our children. We must reduce CO2 pollution now. Rather than continue to rely on
p olluting fossil fuels, we can "Repower America" by using energy sources that don't emit CO2, and make the swit ch to 100% clean electricity.

Response: EPA clarifies that the Class VI GS requirements are designed to ensure consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. The requirements apply to owners or operators of inject ion wells used to inject CO2 for
p ermanent storage. The Class VI GS rulemaking is promulgated under Safe Drinking Water Act authority and does not relate to any endangerment and cause or contribute findings under the Clean Air Act. The Class VI GS requirements do not depend upon, and are unaffected by, Clean Air Act endangerment and cause or contribute findings.

The Agency clarifies that the use of “clean electricit y” is outside the scope of the GS rulemaking. More information on EPA's Endangermen t and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act can be found at http://www.epa.gov/climatech ange/endangerment.html.

Other EPA Comment Codes and Descriptions: 1310 1.1.2.4 Comments on other "out of scope" issues, e.g., pore space ownership Comment: The Supreme Court recognized in Massac husetts v. EPA [FN2] that EPA has authority and, indeed an obligation, under the Clean Air Act to regulate emissions of greenhouse gases, including CO 2, that "cause or contribute to air
p ollution that may reasonably be anticipated to endanger public health or welfare." [FN3] Similarly, the D.C. Circ uit’s remand of the power plant new source performance standards ("NSPS") place s EPA in the position to regulate CO2 emissions from new and also existing s ources within that industrial sector. [FN4] The Environmental Appeals Board EAB also recently has rejected the agency’s arguments that it is not authorized to issu e best available control technology (BACT) emissions limits for CO 2 in the context of a new source air
p ermit decision for a large new coal-fired power plant, under the Clean Air Act’s Prevention of Significant Deterioration (PSD) new source review authority. [FN5]

[FN2: 127 S.Ct. 1438 (2007).] [FN3: Id. at 1460-61.] [FN4: Order, NY, et al. v. EPA, D.C. Cir. No. 06-1322 (Sept. 24, 2007). Once N SPS are set for an industry under sect ion 111(b), 42 U.S.C. §7411(b), the Act requires EPA to set standards for states to regulate emissions from existing sources in that industr y . 42 U.S.C. § 7411(d).] Commenter Name: Anon y mous3 Letter ID: 0138 Comment ID: 23078

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22272[FN5: In re: Deseret Power Electric Coop., PSD App. No 07-03, Slip Op. (Nov. 13, 2008). The memorandum issued December 18, 2008 by Administrator Johnson entitled "EPA’ Interpretation of Regulations that determine Pollutants Covered by Federal Prevention of Significant Deterioration (PSD) Permit Program" (Johnson PSD memo) is procedurally deficient, and, in any even t, states explicitly on its face that it is not intended to supersede the EAB’s decision in the Deseret case. Johnson memo at 2. Nor, indeed, can it lawfully do so.]

Response: The purpose of the Class VI GS regulation is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. The requirements apply only to GS injection technologies includi ng well construction, operation, monitoring and testing technologies. The Supreme Court decision under Massachusetts v. EPA and Clean Air Act (CAA) provisions related to New Source Performance Stan dards (NSPS) and Best Available Control Technology (BACT) determinations are outside the scope of this Class VI GS rulemaking.

The Class VI GS rulemaking is promulgated under Safe Drinking Wa ter Act authority and does not relate to any endangerment and cause or contribute findings under the Clean Air Act. The Class VI GS requirements do not depend upon, and are unaffected by, Clean Air Act endangerment and cause or contribute findings. More information on EPA's E ndangerment and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act can be found at http://www.epa.gov/climatech ange/endangerment.html.

In a separate rulemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Gas Reporting Program at 40 CFR Part 98 to add repor ting requirements for CO2 injection and geologic sequestration. The greenhouse gas reporting requireme nts build on the requirements outlined in the Class VI GS rule with the additional goals of ve rifying the amount of CO2 sequestered and collecting data on any CO2 emissions to the surface from GS facilities.

Other EPA Comment Codes and Descriptions: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 Comment: The preamble to the proposed GS rule states "EPA is not proposing regulations for CO2 under the Clean Air Act (CAA) in this proposed rulemaking". As noted in our
p revious letter and comments, it is clear the Clean Air Act provides au thority to regulate the geologic sequestration of CO2. Therefore CATF urges EPA to reconsider the
p osition stated in the preamble and propose for comment, as part of the contemplated N ODA, the inclusion of GS regulations under the Clean Air Act in the proposed rulemaking.

Response: EPA clarifies that the scope of the GS regulation is limited to injection of CO2, and that all requirements in the GS rule ar e designed for the purpose of protecting USDWs from endangerment. Consequently, this comment is outside the scope of this rulemaking. The SD WA does not provide the UIC Program with the authority to de velop regulations for all areas relate d to GS, such as releases to the atmosphere.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endan g erment. In developin g the final GS rule, the Office of Commenter Name: Kurt Waltze r Letter ID: 0292 Commenter Or g anization: Clean Air Task Force Comment ID: 25277Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

In a separate rulemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Gas (GHG) Reporting Program at 40 CFR Part 98 to add re porting requirements for facilities that conduct GS (subpart RR) and all other facilities that inject CO2 underground (subpart UU). For additional information, see the s ection of the final GS rule preamble enti tled, "How Does Mandatory Reporting of Greenhouse Gases (GHGs) Relate to This Rulema king?” and the GHG Repor ting Program rulemaking and docket.

Comment Code: 1300 1.1.2.3 Comments on other aspects of CCS (capture, transport)



### Individual Comments

Comment: Federal Pipeline Standards for Transpor ting CO2: Co-ordinate with the US Congress and federal agencies to adopt national standards for materials requirements and performance specifications in pipelines used to transmit CO2.

Response: EPA clarifies that the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. Transportation of CO2 via pipelines is outside the scope of the Class VI GS rulemaking.

Comment: As numerous EPA and Department of Ener gy publications have reiterated, the regulation of the geologic storage of CO2 for the purpose of safeguarding underground sources of drinking water (U SDWs) and public health, cannot be isolated from the construc tion of a broad national fram ework for the regulation Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Ener gy and Climate Chan g e Comment ID: 21583

Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Energy and Climate Change Comment ID: 21600of carbon capture and sequestration (CCS) in its myriad curren t and anticipated forms. While technical standards are of paramount importance in addressing safety issues attendant to CO2 injection and storage, there are two other key factors in successfully im plementing an integrated CCS program: regulatory oversight and public acceptance.

Response: EPA clarifies that the Class VI GS regulation is being promulgated under authority of the Safe Drinking Water Act (SDWA). The purpose of the Cl ass VI GS rule is to ensure consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

EPA believes that the Class VI GS regulati on, which builds upon the long-standing protective framework of the UIC program, will provide the regulatory certainty a nd oversight that operators have requested. EPA also believes that tailored requirements to ensure th at GS projects ar e permitted, sited, constructed, operated, and closed in a manner that a voids releases of CO2 wi ll protect USDWs from endangerment and thus may improve public confidence in GS.

Comment: F. Federal Pipeline Standards for Transporting CO2

Recommendation F: Co-ordinate with the US Congress and federal agencies to adopt national standards for materi als requirements and performance specifications in
p ipelines used to transmit CO2.

The EPA's Office of Water has stated th at the transmission of captured CO2 to injection storage sites is somewhat outside the scope of the SDWA ("Proposed UIC Regulations for Geologic Sequestration of Carbon Dioxide" February 2008; See: http://www.epa.gov/safewater/uic/pdfs/ page_uic_washingtondc_feburay2008_summ ary.pdf). However, the EPA is coordinating its issuance of UIC regulations with the US Department of Transportation, and has recognized the importance of maintaining safety standards and risk management practices throughout the various stages of carbon capture, transportation, and storage. Currently in the US, about 3,600 miles of CO2 pipelines ar e in operation, primarily located in Texas and New Mexico. They carry CO2 fr om underground reservoirs, natural gas
p rocessing facilities, ammonia manufacturi ng plants, and a North Dakota coal gasification project to oil fields for use in EOR/EGR (See: http://www.nicholas.duke.edu/nicholas/insider/thegreengrok/co2pipeline/).

According to a recent press release, a Norwegian risk management company is
p artnering with European businesses and governments to establish EU pipeline standards for transmitting large amounts of captured CO2 to onshore and offshore storage sites. The guidelines will relate to issues of "safety, fast propagating ductile fractures, fatigue crack growt h, pipeline operation conditions, flow assurance, corrosion and material compatib ility," and will addr ess all phases of construction and lifetime performance, "includin g the desi g n, testin g , Commenter Name: Anonymous2 Letter ID: 0133 Commenter Or g anization: Sierra Club National Global Warming and Energy Committee and Sierra Club California-N evada Regional Conservation Committee on Ener gy and Climate Chan g e Comment ID: 21616inspection, operation, maintenance and de-commissioning phases"(See: http://www.dnv.com/press_area/press_releas es/2008/developingthe firstco2pipelines tandard.asp) . One important objective of the standards is to standardize the transport of CO2 so that it will become uniformly insurable by private insurance companies.

Reportedly, American-based oil companies are participating in the European rulemaking process, and so presumably wi ll have ongoing information about the standards adopted by the EU. This inform ation can enhance the decision making
p rocess during the coming period that US regulations are being promulgated for all stages of carbon capture, trans portation, and storage. Several 2008 Congressional Research Reports indicate that the US Congress has begun to address the issues related to constr ucting and operating a network of CO2
p ipelines for CCS(See: http://a ssets.opencrs.com/rpts/RL33971_20080117.pdf and http://ncseonline.org/nle/cr sreports/08Apr/RL34307.pdf). When such a network is constructed, it is probable that the Fede ral Energy Regulatory Commission (FERC) and the Surface Transportation Board (STB) will receive jurisdiction over interstate pipelines used for this purpose. Currently, th e Pipeline and Hazardous Materials Safety Ad ministration applies safety requirements to CO2
p ipelines that are mandated by CO2's classification as a Class 2.2 (nonflammable gas) hazardous material unde r DOT regulations (40 CFR 172.101). Since it is likely that a federa lly-administrated hierarchy will be established over the next decade, it is important that th e EPA's terrestrial storage regulations remain compatible with progressive devel opments for the transportation of CO2 to the injection well sites.

Response: EPA clarifies that regul ation of CO2 pipelines is outside the scope of the GS rulemaking. Rather, the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: 3.) The SWP would like to comment on th e compatibility of the proposed rule with other regulatory processes.

The CCS process is extremely complex. The proposed rule is associated with storage of CO2 as it relates to prot ecting USDWs under the UIC program. Other aspects of the process including capture, compression, and transport of CO2 are not addressed within the proposed rule, and rightfully so since those processes are independent of the UIC program. In the overall scheme of permitting a commercial scale CCS site, has any consider ation been given to the compatibility of the UIC proposed rule with other permitting processes (i .e., pipeline, air quality, etc) so as to streamline all regulatory requirement s? The SWP would like to suggest collaboration with othe r permitting agencies, at the state and federal level, as regulatory framewor k development progres ses so that the
p ermitting of an entire CC S project is not unrealisti cally burdensome for the regulators and owners/operators. Commenter Name: Dawn A. Thorne Letter ID: 0134 Commenter Or g anization: University of Utah Energy and Geoscience Institute on b ehalf of the Southwest Re g ional Partnership Comment ID: 21663Response: EPA agrees that a strong regulat ory framework will be importa nt to ensuring that GS is deployed safely. EPA believes that the Class VI GS regulation will provide certainty, consistency, and transparency to owners or operators and the public a bout requirements that apply to GS injection across the United States. The Class VI GS regulation builds upon the long-standing, protective framework of the UIC program, which has been regulating the injection of billions of gallons of liquids for decades. The Class VI GS regulation enhances this existing framework with requirement s for GS wells that are tailored to the unique nature of large scale GS of CO2. These additional protective requirements include more extensive geologic testing, detailed com putational modeling of the AoR and periodic reevaluations, detailed requirements for monitoring a nd tracking the CO2 plume and pressure front, and extended post-injection monitoring and site care.

In response to the suggestion that the Agency devel op an integrated permitting process that addresses the entire CCS process, EPA clarifies that the UIC program’s authority under SDWA is focused on ensuring protection of USDWs from endangerment. The capture and transport of CO2 are outside of the scope of the Class VI GS rulemaking.

Comment: to date with this demonstration. Howeve r, there are other pieces to the puzzle that still need to fall into place to make this a viable option for our continued use of coal in a carbon constr ained world. Affordable, efficient and commercially available ca rbon capture technology is still years away. In addition, because not all existing power plants were built over suitable geologic formations for injection we must contemplate construction of a pipeline infrastructure to transport supercritical CO2 fluid from a power plant to an appropriate injection site. Another huge issue which has yet to be broached by

Response: EPA agrees that a strong regulat ory framework will be importa nt to ensuring that GS is deployed safely. EPA believes that the Class VI GS regulation will provide certainty, consistency, and transparency to owners or operators and the public a bout requirements that apply to GS injection across the United States. The Class VI GS regulation builds upon the long-standing, protective framework of the UIC program, which has been regulating the injection of billions of gallons of liquids for decades. The Class VI GS regulation enhances this existing framework with requirement s for GS wells that are tailored to the unique nature of large scale GS of CO2. These additional protective requirements include more extensive geologic testing, detailed com putational modeling of the AoR and periodic reevaluations, detailed requirements for monitoring a nd tracking the CO2 plume and pressure front, and extended post-injection monitoring and site care.

In response to the suggestion that the Agency devel op an integrated permitting process that addresses the entire CCS process, EPA clarifies that the UIC program’s authority under SDWA is focused on ensuring protection of USDWs from endangerment. The capture and transport of CO2 are outside of the scope of the Class VI GS rulemaking.

Other EPA Comment Codes and Descriptions: 1530 1.2.3.1 State regulatory e fforts on GS (seeking comment) Comment: 6. NRECA ur g es EPA to issue more definitive direction in the Final Rule Commenter Name: Skiles Bo yd Letter ID: 0160 Commenter Or g anization: DTE Ener gy Comment ID: 21267

Commenter Name: James Stine Letter ID: 0163 Commenter Or g anization: National Rural Electric Cooperative Association (NRECA) Comment ID: 21327regarding the regulation of CO2 inj ection activities that cross state boundaries. This issue is ment ioned in the Preamble to the Proposal but receives little attention. See 73 Fed. Reg. at 43497. Rather, EPA simply observes that "some injection activities may raise cros s-state boundary issues that are beyond the scope of this rulemaking." Id. More guidance should be given regarding how such cross-state activities should be re gulated, including making clear in the Final Rule that Owners or Operators of Class VI CO2 GS proj ects will seek a Class VI permit for that operation from the state in which the wellhead is located; in other words, a given state is the permitting body for any Class VI CO2 GS project with a wellhead in that state. EPA should direct states to consult and coordinate with other affected states (i.e ., other states to which the underground portion of the well may exte nd and/or those to which there could be a subsurface release or migration of in jected material) in determining how to avoid duplicative or dueling regulatory systems. NRECA urges EPA to play a leadership role and proact ively address these issues by suggesting procedural guidelines for inter-state regulation and cooperation.

Response: EPA understands that the CO2 plumes for large GS projects may cross state, tribal, EPA Regional, or national bounda ries. The final GS rule, at §146.82(a)(2), requires the owner or operator to identify all State, Tribal, and Territorial boundaries within the AoR. Based on this information, the Director must provide written notifi cation to all States, Tribes, and Te rritories to inform them of the
p ermit application §146.82(b) and ensure that they are involved in any necessary processes (e.g., development of the emergency and remedial re sponse plan (146.94)). The Agency encourages transparency in the permitting process and anticipa tes that State-State/State-Tribal communication on GS permitting will faci litate information sharing and enco urage safe, protective projects.

Because some GS projects will require coordination across State and Tr ibal jurisdictions and plans, EPA will work with the appropriate enti ties to facilitate communication among States and Tribes interested in obtaining Primacy during the implementation phase of the GS regulation. Such communication may involve other organizations such as the Sierra Club, NDWAC, associations, and othe r experts. However, the responsibility for addressing such subjects ultimately rests with th e States and Tribes with primacy.

EPA is developing a series of guidance documents to support the GS rulemaking. These are available on EPA’s website at http://wat er.epa.gov/type/groundwater/uic /wells_sequestration.cfm.

Comment: Electric Reliabil ity -- Pg. 47

APPA believes that potential impacts to el ectric reliability should be considered in
p romulgating the UIC Class VI permitting program rules. N ERC’s study can be found at: http://www.nerc.com/files/2008-Cl imate-Initiative s-Report.pdf

Response: The UIC program’s authority under the SDWA focuses on ensuring that Class VI GS
p rojects are permitted, sited, constructed, operated, monitored, and closed in a manner that protects USDWs from endangerment. Regulation of electricity providers is outsid e the scope of the Class VI GS rulemaking. Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23374Comment: One of the largest hurdles: Parasitic Power

The fundamental challenge confronting the utility industry is in carbon separation and in reducing the parasiti c loss of energy at a power plant. Parasitic loss issues at pow er plants are best explained in Attachments 2 and 3 by Doug Carter. [Please see EPA-HQ-O W-2008-0390-0169.pdf for Attachments 2 and 3.] These two papers explain to both laym en and technical experts why parasitic energy could be one of several "deal killer s" for new power plan ts with GS.[FN4] These parasitic are problems that are ve ry fundamental and will determine whether power plants pursue this tec hnology or opt for another type of generation such as nuclear power or perh aps natural gas (which has roughly half of the carbon dioxide as coal). See Figure 2 which highlights the processes which contribute to the parasitic power demands of CCS. Even if carbon separation technology is commer cially demonstrated at > 30 MW in the next few years, parasitic power or energy losses ar e a huge disincentive to use this new generation technology.

[Please refer to the p. 19 of the pdf file for Figure 2 of Parasitic Power Losses in CCS Power Plant]

The storage issues can be equally daun ting but the fundamental question of separation and parasitic power are so overwhelming that it is not entirely clear how many municipal governments will want to pursue this technology until those economic issues (especially the parasitic power) are sorted out. The other remaining issue in the three legged footst ool is the question of infrastructure and logistics. Without a ma ssive investment in infrastructure for additional
p ipelines and booster compressors, APPA w onders how many of these plants will be built in the first 10-30 years. The oil and gas industry had 35 years to build up the essential infrastructure for CO2 in jection in the context of oil and gas recovery. This infrastructure includes pipelines, booster compressors and feedstock delivery. See Figure 3 for a map showing current CO2 pipelines in the U.S. [Please refer to p. 21 of the pdf file for Figure 3 of U.S. CCS Pipeline Map] The industry also has systems in place to remove/treat produced waters. These systems are not in place in states with no oil or gas production. Those oil and gas recovery fields were and are highly profitable and had a revenue stream to offset the investments in deli very methods such as construction of
p ipeline or adaptation of existing natural gas pipelines, booster compressors, or for the use of tankers for some small quantities of CO2 for use at production fields. The economics for power plants ar e not yet ripe for such investments because power plants would not have the additional revenue stream coming in for infrastructure investments coming off the oil and ga s production reve nue stream

N or are the right of way or surface right issues sorted out by state law before CO2 can be either transported across jurisdictional lines or stored as a commodity without surface prope rty rights being sorted out. These commercial and
p ractical impediments to ge ologic sequestration (GS) are enormous and should not be minimized simply because we wish to find a technology that will work to enable us to use coal or natural gas in the future. These commercial, technology and feasibility impediments ar e not EPA’s problems to fix- b ut they are mentioned Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23393here because we are trying to inject "reality" into the zealous discussions in the trade press, on televisi on, and at coal plant heari ngs about the viability of geologic sequestration at new coal plan ts in 2008. These same issues apply to the existing coal plant fleet. These same co mmercial issues apply in the context of natural gas generation sources wher e no carbon separation technology exists today without dramatic para sitic power impacts which would typically be too onerous for existing plants.

[Figure 3. Please refer to p. 21 of the pdf file for Figure 3 of U.S. CCS Pipeline Map]

[FN4] L.D. Carter, White Paper, "Carbon Capture and Storage From Coal-based Power Plants: A White Paper on Technol ogy for the American Public Power Association (APPA)," May 2007 and L.D. Carter, White Paper, "Retrofitting Carbon Capture Systems on Exis ting Coal-fired Power Plants," November 2007

Response: EPA emphasizes that the UIC program’s authority under the SDWA is focused on ensuring that Class VI CO2 injection projec ts are permitted, sited, constructed, operated, monitored, and closed in a manner that protects USDWs from endangerment. The capture and transport of CO2 are not within the UIC program’s authority.

Comment: Electricity Reliability

While the EPA UIC Class VI program perm itting proposed rule did not call for comments on electricity reliability, we o ffer our comments to NERC on Reliability Impacts of Clim ate Change Initiatives, dated July 16, 2008, which we believe should be considered. These are in cluded in the Appendix. [See EPA-HQOW-2008-0390-0169.pdf for these comments.] NERC’s "Reliability Impact of Climate Change Initiatives" (Nov. 2008) link is: http://www.nerc.com/files/ 2008-Climate-Initiatives-Re port.pdf to the final report (23pp).

Response: As described above, the capture and transpor t of CO2 are not within the UIC program’s authority. The UIC program’s authority under the SDWA focuses on ensuring that Class VI GS projects are permitted, sited, constructed, operated, monitored, and closed in a manner that protects USDWs from endangerment.

Comment: DISCUSSION

1. Legal and Regulatory Challenges to Commercial-Scale CO2 GS

It is important to recogni ze that the development of a viable, large-scale commercial CCS program requires resolution of technical, policy, and legal issues that are beyond the scope of th is rulemaking. The General Accounting Office ("GAO") recently issued a report entitled "Climate Change - Federal Actions Will Greatl y Affect the Viabilit y of Carbon Capture and Stora g e As a Ke y Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23433

Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utility Solid Waste Ac tivities Group (USWAG) Comment ID: 23469Mitigation Option" wh ich emphasizes that signifi cant technological barriers involving CO2 capture technologies must be resolved before a successful CO2 CCS
p rogram of the scale envisioned by policym akers can be achieved. GAO-08-1080 at 3-5 (September 2008) ("GAO Report"). The GAO Report also references a number of regulatory and legal uncertain ties involving CO2 storage, leakage, and ownership issues, the resolution of which is critical to a successful CCS program. Id. Federal agencies must also work toge ther to "examine how CO2 pipeline infrastructure might be regulated to accommodate commercial-scale CCS," as well as how "CO2 emissions reducti ons from CCS will be treated in a future emissions trading scheme." Id. at 4.

Response: EPA emphasizes that the UIC program’s authority under the SDWA is focused on ensuring that Class VI CO2 injection projec ts are permitted, sited, constructed, operated, monitored, and closed in a manner that protects USDWs from endangerment. The capture and transport of CO2 are not within the UIC program’s authority.

Other EPA Comment Codes and Descriptions: 1540 1.2.3.2 Climate change legislation Comment: Single, Clear Regulatory Structure

There should be a single, clear regulatory structure applicable to CCS rather than multiple, ill-suited regulatory and liability statutes and regulations that likely will discourage CCS To that e nd, the CCS Alliance believes that a beneficial approach would be to enact at the federal level a new regulatory structure specific to CCS.

Response: EPA acknowledges that GS falls within the broader context of CCS and the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordina ted with other Agency program of fices and across federal agencies (e.g., with the Department of Energy; United St ates Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcem ent, formerly the Minerals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applic ability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

EPA is also aware that states are currently in various stages of devel oping statutory frameworks, regulations, technica l guidance, and strategies for addressi ng CCS and GS. States can use multiple authorities beyond those afforded under the SDWA and UIC regulations, including laws and policies addressing surface access and land ri ghts, unitization of fields, pore space ownership, mineral rights, worker safety and emergency prepar edness, and maximization of state oil and gas resource exploitation. EPA plans to work closely with states and tribes as they develop Class VI primacy programs in this broader context. EPA adds that st ates may adopt more stringent stan dards for Class VI wells than the Federal requirements. Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23800In a separate rulemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Gas (GHG) Reporting Program at 40 CFR Part 98 to add re porting requirements for facilities that conduct GS (subpart RR) and all other facilities that inject CO2 underground (subpart UU). For additional information, see the s ection of the final GS rule preamble enti tled, "How Does Mandatory Reporting of Greenhouse Gases (GHGs) Relate to This Rulema king?” and the GHG Repor ting Program rulemaking and docket.

Other EPA Comment Codes and Descriptions: 1310 1.1.2.4 Comments on other "out of scope" issues, e.g., pore space ownership; 1400 1.2 Comments on EPA's Au thority to Regulate Injection of CO2 Comment: XII. RELATED ISSUES, NOT RAISED IN THE PROPOSED RULE, THAT REQUIRE RESOLUTION

The SDWA does not provide EPA authorit y to develop regulations for many important areas related to the geological sequestration of CO2. Thus the draft rule cannot address all of the potential im pediments to CCS development. Even if EPA were to promulgate a final UIC rule that encourages development of these critical technologies, there are other ke y factors that would need to be
p roperly addressed before major investme nt in these technologies can be expected.

The following sets forth key issues that will not be resolved through this rulemaking but are linked inextricably to the successful development and implementation of CCS technology.

A. EMINENT DOMAIN AUTH ORITY TO FACILITATE PI PELINE CONSTRUCTION

Energy facilities for the public convenien ce and necessity, such as electric transmission facilities and natural gas pipelines, are able to make use of state or federal eminent domain authority to ensure that private landowners cannot block a project necessary for the public good. Eminent domain authority should be available for CO2 pipelines for CCS wh en it is necessary to cross private
p roperty. A substantial CO2 pi peline network may be re quired for the transport of CO2 from sites where it is produced to an injection site. CO2 pipelines for CCS clearly should be consid ered to be used for the public convenience and necessity.

B. DETERMINATION OF SUB-SURFACE PROPERTY RIGHTS

The government must address the ability to gain sufficient property rights to deep saline formations to conduct geologic sequestration. State property ownership regimes vary, but surface owners typically are considered to own
p roperty below the surface to the center of the earth. Safe sequestration of CO2 will not have any effect on the surface, but GS injections will result in underground plumes that may stretch across many square miles under the property of multiple surface prope rty owners. Propert y ownership issues have been resolved successfully in the context of EO R, but it should not be assumed that the same will be true fo r GS. Eminent domain authorit y should be available to Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23877obtain rights to subsurface storage space for geologic sequestration because of its public benefit.

C. RESOLUTION OF SURFACE LIABILITY ISSUES

Though this Proposed Rule is limited in its scope to undergr ound injection of CO2 and the potential risks and resulting liabilities, issues regarding risks and liability at the surface must be addressed for CCS t echnology to fully develop. These include liability for majo r and sudden releases, seismic activity and ground heave, as well as liability under any GHG emission control regime when sequestered CO2, for the storage of which credits or offsets have been granted, is subsequently releas ed into the upper atmosphere.

Response: EPA acknowledges that the issue of GS falls within the broader context of CCS. EPA received a number of comments indi cating that the Agency should further explore environmental and regulatory issues beyond the scope of the GS rule as proposed. This comment is outside the scope of this rulemaking.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

EPA recognizes that liability is an important issue to owners or opera tors but the Agency does not have authority under the SDWA to transfer long term liability from owners or operators to the state or federal government. Therefore, liability remains with the owner or operator.

Comment: B. The Proposed Regulation Does Not Cover All Parties Involved in CCS Even Though Their Actions Create a Risk of Endangerment to USDWs.

The proposed regulation applies only to "o wners or operators of injection wells that will be used to inject CO2 into the subsurface for the purposes of GS." 73 Fed. Reg. at 43,492; see id. at 43,534 (proposed 40 C.F.R. §144.18). Other
p arties involved in a CCS project, incl uding the CO2 generator, transporter an d surface and sub-surface property owner(s), are not covered. As EPA notes, though, "[t]he SDWA provides EPA with the authority to develop regulations to
p rotect USDWs." Id. at 43,495; see also 42 U.S.C. §300h(a)-(b), (d). That authorit y extends over all actors involved in the CCS process (not j ust the Commenter Name: Wendy Jacobs Letter ID: 0183 Commenter Or g anization: Harvard Law School Environmental Law and Policy Cente r Comment ID: 25155injection well owner or operator), at least to the extent their actions may contribute to the risk of harm to USDWs.[FN11]

For instance, EPA has recognized that "co- contaminants in the CO2 stream could endanger a USDW if the injectate migrates into a USDW." 73 Fed. Reg. at 43,497. The "types of impurities and their concentrations in the CO2 stream are likely to vary by facility, coal composition, plant operati ng conditions, and pollution removal technologies." Id. at 43,503. Yet the proposed regulation’s current standard for stream purity is loosely defined. The proposed regulation allows injection of a stream with "incidental associated substances derived from the source materials and the capture process, and any substances added to the stream to enable or improve th e injection process." Id. at 43,535 (proposed 40 CFR § 146.81(d) (definition of "carbon dioxide stream")). By regulating CO2 generators and CO2 stream treatment (purification) facilities directly, EPA could reduce the likelihood that a contamin ated CO2 stream would be injected into a GS well and thereby reduce the likelihood that such contaminants would endanger a USDW.[FN12] EPA should therefore consider setting specific requirements for the maximum concentrations of "inc idental substances" in injected CO2 streams to reduce the uncertainty about the proper level of treatment required. By imposing financial assu rance requirements on those parties, EPA could also reduce the likelihood that costs and dama ges arising from such contamination would go unpaid, for example, if such costs exceeded the security posted by the owner or operator. Regulator y oversight would make these firms "more likely to undertake operating decisions that consid er environmental (and remediation) costs." WRI ISSUE BRIEF at 6.

[FN11] ELPC agrees, however, that EPA doe s not have authority under the SDWA to address all of the conduct of all of the parties involved in CCS or all of the risks posed by CCS, and therefore urges EPA to advocate on behalf of a broader mandate from Congress. See discussi on at Part III(C)(1)(b). supra.

[FN12] Note that even such a consideration would fall short of protecting many
p rivate sources of well-water which coul d be harmed by CO2 migration. EPA should
p rovide for mandatory consultation with owners of private wells before
p ermitting any sequestration project in an area with private well use.

As a matter of equity, parties other than owners and operators should also be regulated to "ensure that risks are borne by those who share in the benefit of [GS] technologies." Id. at 9. For example, geological sequestration may "allow some [generators of CO2] to extend the li fe of their existing capital investment in plant machinery or plant processe s." 73 Fed. Reg. at 43,531. Moreover, since "it is caps on greenhouse gas emissions that will explicitly establish a price for CO2 and will encourage utilities and others to invest in CCS in order to meet those caps," it is the genera tors of the CO2 -along with their customers-who may receive credits fo r sequestration. KLASS AND WILSON at 13. All parties who benefit from GS of CO2 should help bear the risks attendant to that sequestration.

Response: EPA clarifies that the Class VI GS rule applies to owners or operators of wells that will be used to inject CO2 into the subsurface for the purpose of long-term storage. EP A clarifies that regulating CO2 generators and transpor ters is outside the scope of the Cla ss VI GS rulemaking. The Class VI GSrule is designed to ensure consistency in perm itting underground injection of CO2 at GS operations across the United States and provi de requirements to prevent endange rment of USDWs in anticipation o f the eventual use of GS to reduce CO2 emissions.

The GS rule does not set generi c purity standards for CO2 injectate streams (e.g., a percent CO2). Instead, the GS rule addresses the quality and quantit y of impurities by requiring owners or operators to submit information on the source of the CO2 and its physical and chemical properties. Specifically, the GS rule requires the owner or operator to submit data about the site, including an analysis of the chemical and physical characteristics of the CO2 stream, as required at §146.82(a)(7)(iv), and information on the compatibility of the CO2 stream wi th fluids in the injection zone and minerals in both the injection and the confining zones and the materials used to constr uct the well, per §146.82(c) (3). This information can help the Director determ ine the potential for geoc hemical reactions between the injectate (CO2) and the host geologic formations, which could resu lt in the plugging of pore spaces or the dissolution of formation minerals.

Comment: - In order to more clearly illustrate the actual risks of CO2 transport and storage, EPA should work to dispel concer ns that geologic sequestration could be encumbered with those requirements excep t possibly through the commingling of a captured CO2 stream with an actual waste stream.

Response: The Class VI GS rule applies to owners or opera tors of wells that will be used to inject CO2 into the subsurface for the purpose of long-term storage. EPA clarifies that regulating CO2 transportation is outside the scope of the Class VI GS rulemaking. The Class VI GS rule is designed to ensure consistency in permitting underground injecti on of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

EPA received many comments regarding the applicabil ity of the RCRA regulations and statute to CO2 streams that are geological ly sequestered under the final Class VI UIC well requirements. As a result, EPA has decided to initiate a separate proposed rule making specifically to ex amine the issue of RCRA applicability to CO2 streams be ing geologically sequestered, in cluding the possible option of a conditional exemption from the RCRA requirements for CO2 GS in Clas s VI wells. EPA will consider these comments as part of its deve lopment of that proposal. The Agency will consider issues particular to RCRA in the context of that separate rulemaking, and recommends that the commenter read that
p roposed rule when it is published. The Agency notes that commenters who wish to submit comments on the RCRA proposal will need to do so during th e comment period for that rule. Finally, EPA also notes that the final GS rule, which adds new regul ations for Class VI wells under the Safe Drinking Water Act (SDWA), is not making any changes to the RCRA regulations.

The GS rule does not set generi c purity standards for CO2 injectate streams (e.g., a percent CO2). Instead, the GS rule addresses the quality and quantit y of impurities by requiring owners or operators to submit information on the source of the CO2 and its physical and chemical properties. Specifically, the GS rule requires the owner or operator to submit data about the site, including an analysis of the chemical and physical characteristics of the CO2 stream, as required at §146.82(a)(7)(iv), and information on the compatibility of the CO2 stream wi th fluids in the injection zone and minerals in both the injection and the confining zones and the materials used to constr uct the well, per §146.82(c) (3). This information can help the Director determ ine the potential for geoc hemical reactions between the in j ectate (CO2) and the host g eolo g ic formations, which could result in the plu gg in g of pore spaces Commenter Name: John Kin g Letter ID: 0211 Commenter Or g anization: Shell Exploration and Production Compan y (SEPCo) Comment ID: 22755or the dissolution of formation minerals.

Other EPA Comment Codes and Descriptions: 1510 1.2.2.3 Need for additional study Comment: o Potential ancillary effects of CCS -- such as pressure waves, which could move hundreds of miles and affect sequestration sites -- must be evaluated.

Response: EPA agrees that continued research in all GS associated fields will be integral to development of GS technology. EPA notes that a study conducted by Lawrence Berkeley National Laboratory evaluated basin-scale hydrol ogy and pressure changes that could occur as a result of GS; this study is described in EPA’s Notice of Data Availabil ity and Request for Comment (74 FR 44802, see references to Birkhol zer et al. 2008b).

Comment: Very little data is available to evalua te the energy balance of various carbon capture processes. The evaluations avai lable limit the efficiency of carbon capture (CC) to a percent recovered from the feed stack to the emission stack. Capturing the carbon is very energy intensive and may increase energy demand by up to 50%. (www.lowtechmagazine .com accessed October 27 2008).

According to Greenpeace In ternational: False Hope: Why carbon capture and storage won't save the climate, "capturing and storing carbon uses lots of energy; anywhere from 10-40% of a power station’s capac ity. An energy penalty of j ust 20% would require the c onstruction of an extra power station for every four built. These reductions in efficiency will require more coal to be mined, transported, and burned, for a power stat ion to produce the same amount of energy as it did without CCS."

The attached summary of a study by Wuppert al Institute, the German AerospaceCenter (DLR), Zentrum für Sonnenenergie- und Wasserstoff-Forschung BadenWürttemberg (ZSW) and the Potsdam Institut e for Climate Impact Research (PIK) for the German government (the full re port available at: www.wupperinst.org, accessed on line Dec. 23 2008) offers an in depth study of CCS that evaluates the various power plant designs, transpor t, and storage costs; accesses life cycle, ecological criteria, carbon neutrality etc. Estimates in the study show a 20 to 40% increase in energy consumpt ion and the process will only lower emissions of CO2, ignoring the increases of other greenhouse gases (GHG). [SEE EPA-OW-2008-0390-0273.PDF FO R THIS DOCUMENT.]

Consuming an additional 20 to 50% more coal to energize the capture of CO2 is a questionable tactic that must supported by transparent data analysis.

Response: EPA clarifies that CO2 capture and the energy demands of CCS opera tions are outside the scope of the Class VI GS rulemaking. The UIC program’s authority under the SDWA focuses on ensuring that GS projects are permitted, sited, cons tructed, operated, monitored, and closed in a manner that protects USDWs from endan g erment. Commenter Name: Diane VanDe Hei Letter ID: 0213 Commenter Or g anization: Association of Metropolitan Water Agencies (AMWA) Comment ID: 22938

Commenter Name: Mar y Munn Letter ID: 0273 Commenter Or g anization: Fond du Lac Reservation Comment ID: 24083Other federal agencies (e.g., DOE and the U.S. Geological Survey) have conducted research on available storage capacity and determinations of th e feasibility of capturi ng and storing CO2 at the scales needed to address climate change. These agencies, along with pr ivate entities, have identified large areas for potential sequestration in capacity studies. For example, in 2008, USGS initiated development of a methodology for estimating the capacity to store CO2 in geologic formations of the United States. In 2009, USGS published a propos ed, risk-based methodology for GS capacity estimation. This report, Development of a Probabilistic Assessment Met hodology for Evaluation of Carbon Dioxide Storage, is available at http://pubs.usgs.gov/of/2009/1035/ofr2009-1035.pdf.

Comment: Recommendations:

· A thorough mass balance of the CO2 generated in the participating fossil energy processes, generating CO2 must be demonstrated to prove the feasibility of the proposal; including mining and trans port of the fossil fuel to power
p lants, extraction and compression of the CO2 emissions, transport, and injection the CO2 into a geologic formation.

Response: EPA clarifies that other federal agencies (e .g., DOE and the U.S. Geological Survey) have conducted research on available storage capacity and de terminations of the feas ibility of capturing and storing CO2 at the scales needed to address climate change. These agencies, along with private entities, have identified large areas for pot ential sequestration in capacity studies. For example, in 2008, USGS initiated development of a methodology for estimating th e capacity to store CO2 in geologic formations of the United States. In 2009, USGS published a proposed, risk-based methodology for GS capacity estimation. This report, Development of a Probabilistic Assessment Met hodology for Evaluation of Carbon Dioxide Storage, is available at http://pubs.usgs.gov/of/2009/1035/ofr2009-1035.pdf.

The UIC program’s authority under the SDWA focuse s on ensuring that GS projects are permitted, sited, constructed, operated, monitored, and closed in a manner that is protective of USDWs. Coal mining and CO2 capture and transport are outside the scope of the Clas s VI GS rulemaking.

Comment: The commitment of resources; human, materi al, and capital, required to construct the network of pipelines and wells fo r a project that is most likely energetically untenable, ca nnot be supported without a proper evaluation of carbon throughput of the entire process.

Response: As described above, CO2 transport is outside the scope of the Class VI GS rulemaking, which is focused on ensuring that Class VI CO2 in jection projects are permitted, sited, constructed, operated, monitored, and closed in a manner that is protective of USDWs.

Comment: I would like to start my comments in ta lking about the general approach the EPA has taken to re g ulate sequestration. While it is g reat that we are talkin g about Commenter Name: Mar y Munn Letter ID: 0273 Commenter Or g anization: Fond du Lac Reservation Comment ID: 24086

Commenter Name: Mar y Munn Letter ID: 0273 Commenter Or g anization: Fond du Lac Reservation Comment ID: 24091

Commenter Name: Jonah Fruchte r Letter ID: 0526 Commenter Or g anization: Sierra Club Comment ID: 21491keeping water clean in Colorado, I do not understand why EPA is not taking a comprehensive approach to environmenta l regulation. We should be talking about how to regulate the capture, transfer, le akage problems, public health issues and water safety all in one package. I do not think it is helpful to draft environmental regulation in a piecemeal fashion.

The environment does not function as separa te pieces. It is in terconnected. What affects the water, affects the land and what affects the land affects our air and so on and so forth.

Furthermore it is cumbersome and ine fficient to form regulatory policy in separate parts. I would not suggest you use piecemeal regulation for anything, I mean, including the environment. Environmental regulation should always reflect a comprehensive approach rather than the singular and isolated approach we are taking with only regulating water safety.

Response: EPA clarifies that the Class VI GS regulation is being promulgated under authority of the Safe Drinking Water Act. The purpose of the Class VI GS rule is to ensure that where GS technologies are deployed, GS is performed in a manner that pr otects USDWs from endangerment. CO2 capture and transport are outside the scope of the Class VI GS rulemaking.

EPA is using an adaptive approach to regulating Class VI wells. EPA plans, every six years, to collect and review data on Class VI projects to determ ine whether the appropria te amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or nece ssary. The adaptive approach may include solicitation of input and expertise from experts and stakeholde rs, similar to the consultations held to develop the current rule.

Comment Code: 1310 1.1.2.4 Comments on other "out of scope " issues, e.g., pore space ownership



### Individual Comments

Other EPA Comment Codes and Descriptions: 1210 1.1.1 Comments about the proposed rule Comment: We believe the following issues warrant additional review by the Environmental Protection Agency:

1. The potential negative impact to larg e CO2 deep saline formation geologic sequestration projects resulting from the reference in these regulations to storage rather than disposal, implying the CO2 may have value or is even actually a commodity. Large projects could have a CO2 plume covering many square miles. The reference to storage may result in the operator having to rent or pay for the use of pore space for storage, wh ich may involve deal ing with numerous
p arties, considerable legal work and considerable costs.

2. The potential adve rse impact to Class I industrial waste disposal well Commenter Name: Michael H. Cochran Letter ID: 0108 Commenter Or g anization: Bureau of Water, Division of Environment, Kansas Department of Health & Environment (KDHE) Comment ID: 21942p rogram that could result fr om the concept of storage described in above item #1.

Response: EPA acknowledges that issues such as pore space ownership and surface and subsurface
p roperty rights are important issues that need to be addressed; howev er, these are generally addressed though state regulations and are outside of the UIC program’s authority under the Safe Drinking Water Act (SDWA). EPA adds that the requirements apply to owners or operators of injection wells used to inject CO2 for permanent storage, and do not apply to owners or operato rs of Class I wells.

EPA believes that developing a consistent regulatory framework will ensure that there is adequate opportunity for public involvement on the permitting process and that all US DWs are protected from endangerment.

Other EPA Comment Codes and Descriptions: 1350 1.1.3.3 Comments on the need for GS technology; 3460 2.2.2.3 Acceptable corrective action techniques for GS sites (e.g., cements) Comment: For the past four years, our comp any has been field testing our
p roprietary systems and methods for utiliz ing a low melting point fusible metal alloy to mold in situ plugs in wells to repair gas leakage problems. Our focus has been on repair of vent gas flows that occur because of channels that exist within the cement surrounding production casi ng in wells. Our field tests have been carried out with perm ission of the Alberta Energy Resources Control Board ("ERCB") and under their scrutiny. We presently have a proposal under consideration by the ERCB and the Canadi an Association of Petroleum Producers (CAPP) to add our methods to the approve d well abandonment pr otocols presently under review in Alberta.

We believe our methods are di rectly applicable to th e problem of long term leakage of sequestered GHG from wells th at penetrate a reservoir used for the sequestration. Obviously, it makes neither economic nor environmental sense to capture, concentrate, compress, deliver, a nd inject CO2 into depleted reservoirs or saltwater formations if there is not a reliable sealing method used on existing wells in that reservoir to pr event the CO2 leaking back into the atmosphere. We believe that our plugging me thods can assure l ong term success in
p reventing this leakage.

We use an alloy of bismuth and tin for our sealing medium. This alloy is nontoxic and will not corrode or cause corrosion in the relevant well environment from either chemical or galvanic proce sses. We believe we can seal a well against gas flow even if the well casi ng has been entirely corroded away. The important properties of the alloy that cause it to be effective are:

1) it expands about 1% by volume when so lidifying from the liquid phase; 2) it is impermeable to gas flow; 3) it seals effectively in dirty oily casing; 4) it has a high specific gravity to facilitate displacement of other fluids present during the deployment process; and 5) it has a very low viscosity and surface tension such that it will enter small fissures, and absorb into and wet
p ermeable rocks such as sandstone. Commenter Name: Homer Spence r Letter ID: 0120 Commenter Or g anization: Canitron S y stems Inc. Comment ID: 22071Only small amounts of the alloy are required to form a seal with the differential pressure strengt h required to seal GHG sequestration wells. We set the plugs using an electric heater deployed on a wire line. The procedure is both fast and inexpensive. We have data to back the above contentions, including corrosion tests carried out in a CO2/saltwater environment with a pH of 3 that indicate plug life in steel casing in excess of 10,000 years.

Response: EPA thanks the commenters for the informati on on available well materials. EPA believes that the regulation affords owners or operators flexibility to us e various materials and techniques to
p erform corrective action, provided they meet with the Dire ctor's approval.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Proposed Financial Responsibility a nd Long-Term Care Requirements

-There is no language in the proposed regulation that covers compensation to homeowners for the degradation or loss of a water supply.

-EPA should consider how Class VI wells a nd associated GS projects could impact the ownership of mineral right s in formations that are penetrated en route to the CO2 storage reservoir. Some suggestions include a mechanism to require disclosure of mineral right s that may be impacted by a sequestration project and how such ownership issues will be resolved.

-If phased corrective action (plugging of existing pene trations) is to be approved, then the operator must post a 100 percent performance bond with the
p ermitting agency before the permit is is sued. The performance bond is to be in the amount necessary for the permitting ag ency to immediately complete the corrective action should the owner/operator fail to timely do so.

Response: EPA clarifies that the goal of the financial re sponsibility requirements is to ensure that financial resources are available to preven t endangerment of USDWs from improper plugging, remediation, and management of wells in the event that the owner or operato r experiences financial difficulties. EPA would also like to highlight th e emergency and remedial response plan required under the rule. This includes the cost to perform any neces sary responses or remediation to address potential USDW endangerment. See the preamble to the fina l rule for more detail s on the emergency and remedial response requirements.

EPA clarifies that pore space ownership and surfa ce and subsurface property and mineral rights are outside the scope of the UIC GS rulemaking. EPA rec ognizes that many of thes e issues are the purview of the states and any of these issues as they re late to GS will need to be addressed though state regulations. The purpose of the Class VI GS rule is to ensure that where GS technologies are deployed, GS is performed in a manner that protects USDWs from endangerment.

EPA agrees with the comment on phased correctiv e action. The GS rule, at §146.85(c), requires the owner or operator to have a detail ed written estimate, in current dol lars, of the cost of: performing corrective action on wells in the AoR, plugging the injection well(s), PISC and site closure, and

emer g enc y and remedial response. A cost estimate must be prepared separatel y for each of these Commenter Name: John Han g e r Letter ID: 0130 Commenter Or g anization: Penns y lvania Dept. of Env. Protection Comment ID: 21514activities and be based on the costs to the owner or operator of hiring a thir d party (who is neither a
p arent nor a subsidiary of the owner or operator) to perform the activities. EPA clarifies that owners or operators will need to demonstrate and maintain fi nancial responsibility for all corrective action at the time of Class VI well permitting, before the onset of injection operations. See the final rule and
p reamble for further discussion of EPA's fina l approach to financial responsibility.

Comment: Does this include any Carbon diooxide rel eased from carbonated beverasges such as soda and beer?

Response: EPA clarifies that the final Class VI GS rule fina l rule applies to owners or operators of wells that will be used to inject CO2 into the subsurface for the purpose of long-term storage. The purpose of the Class VI GS rule is to ensure consistenc y in permitting underground in jection of CO2 at GS operations across the United States and provide re quirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: E. Other Areas of Concern

The proposed UIC regulations raise many other questions, creating additional uncertainty. These concerns include but are not limi ted to the following:

- Economic liability related to selling car bon credits, and how it relates to this regulation. - Impact on underground coal mines, conflicts regardi ng mineral ownership, and
p ossible mineral takings. - Development of geological horizons below the carbon sequestrati on horizon but in the same area. EPA should retain the flexibility currently available in the other UIC
p rograms. EPA's Class VI program should not interfere with minera l extraction (oil and gas specifically) through the imposition of restrictions in CO2 storage fields. - Potential liability of landowner with CO2 storage area beneath the property.

Response: The purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the US and prevent endangerment of USDWs in anticipation o f the eventual use of GS to reduce CO2 emissions. EP A clarifies that carbon crediting, mining, pore space ownership, and surface and subsurface property and mineral rights are outside the scope of the GS rulemaking. EPA clarifies that many of these issues are under the purview of states, and any of these issues as they relate to GS will need to be addressed though state regulations.

However, the Agency acknowledges that these issues are important and is addressing them using other regulatory authorities. For example, in a separate ru lemaking under authority of the Clean Air Act, EPA is amending the GHG Reporting Program at 40 CFR Part 98 to add reporting requirements for CO2 injection and GS. The greenhouse gas reporting require ments build on the requirements outlined in the GS rule with the additional goals of verifying the amount of CO2 seque stered and collec ting data on any CO2 emissions to the surf ace from GS facilities.

With re g ard to whether CO2 is considered a commodit y , EPA clarifies that the GS rule does not address Commenter Name: W.J. Curran Letter ID: 0137 Comment ID: 23077

Commenter Name: Robert Bessette Letter ID: 0139 Commenter Or g anization: Council of Industrial Boiler Owners (CIBO) Comment ID: 23088the status of CO2 as a pollutant or commodity a nd that EPA regulates both pollutants and commodities under the UIC provisions. In addition, whether or not a fluid could be sold on the market as a commodity is outside the scope of EPA’s authority under the SDWA to protect USDWs. The Class VI GS rulemaking is promulgated under Safe Drinking Water Act authority and does not relate to any endangerment and cause or contribut e findings under the Clean Air Act. The Class VI GS requirements do not depend upon, and are unaffected by, Clean Air Act endangerment and cause or contribute findings.

The Agency clarifies that the final GS rule does not require owners or operators to use GS technologies, nor does it impact business as usual for Class II owners or operators that are injecting CO2 to enhance
p roduction of oil or gas. Owners or operators that choose to transition from EOR to GS may do so,
p rovided they meet the requirements for Class VI wells.

Regarding long-term liability, once an owner or opera tor has met all regulatory requirements under Part 146 for Class VI wells and the Director has appr oved site closure pursuan t to requirements at §146.93, the owner or operator will generally no longer be s ubject to enforcement for regulatory noncompliance. Furthermore, their financial inst rument as required under §146.85 will be released if it was not used. However, even if a site closure is approved under §146.93, an owner or operator ma y be held liable for regulatory noncompliance (including violation of 40 CFR 144.12) in certain circumstances. For example, an owner or operator may be held liable for regulatory noncompliance even after site closure was approved if the Director relied on erroneous information (e.g., erroneous modeling data) provided by the owner or operator when approving site closure.

Separate from EPA’s authorit y to enforce regulatory compliance, an owner or operator may be subject to a §1431 response order even after proper site closure is approved under §146.93. Under §1431 the Administrator may require an owner or operator to take necessary response measures if he or she receives information that a contaminant is present or is likely to enter a public water system or an USDW, which may present an imminent and substantia l endangerment to the heal th of persons, and the appropriate State and local authorities have not acted to protect the health of such persons. The action may include issuing administrative orders or commencing a civil action for appropriate relief against the owner or operator of a Class VI well. If the owner or operator fails to comply with the order, they may be subject to a civil penalty for each day in which such violation occurs or failure to comply continues.

Comment: UIC program and to develop a new Class VI for CO2GS well is appropriate. ODEC also appreciates EPA's rec ognition that while the new re gulations at hand must be within the scope of the SDWA, there are a number ofvery important issues (such as long term liability) that are outside the scope of the act but are highly pertinent to developing a viable GS program and we are glad that EPA is willing to discuss these issues as part of this regulatory proposal.

Response: EPA clarifies that the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA recognizes the importance of providing clear, fl exible, scalable, and appropriate regulations. EPA believes that the Class VI GS regulation will pr ovide certainty to industr y and the public by providing consistency in requirements across the U.S. and tran sparency about what requirements apply to owners or operators. Commenter Name: Kenneth Alexande r Letter ID: 0146 Commenter Or g anization: Old Dominion Electric Cooperative (ODEC) Comment ID: 21707EPA notes that long-term liability is outside of the scope of the GS rulemaking and is not addressed in the GS rule. SDWA does not contain any express provisions addressing liability. An owner or operator will be held liable for any pe rmit violations under SDWA §1423.

Under the final GS rule, once an owner or operato r has met all regulatory requirements under Part 146 for Class VI wells and the Direct or has approved site closure pur suant to requirements at §146.93, the owner or operator will ge nerally no longer be subject to enfo rcement for regulat ory noncompliance. Furthermore, their financial inst rument as required under §146.85 will be released if it was not used. However, even if a site closure is approved under §146.93, an owner or operator ma y be held liable for regulatory noncompliance (including violation of 40 CFR 144.12) in certain circumstances. For example, an owner or operator may be held liable for regulatory noncompliance even after site closure was approved if the Director relied on erroneous information (e.g., erroneous modeling data) provided by the owner or operator when approving site closure.

Separate from EPA’s authorit y to enforce regulatory compliance, an owner or operator may be subject to a §1431 response order even after proper site closure is approved under §146.93. Under §1431 the Administrator may require an owner or operator to take necessary response measures if he or she receives information that a contaminant is present or is likely to enter a public water system or an USDW, which may present an imminent and substantia l endangerment to the heal th of persons, and the appropriate State and local authorities have not acted to protect the health of such persons. The action may include issuing administrative orders or commencing a civil action for appropriate relief against the owner or operator of a Class VI well. If the owner or operator fails to comply with the order, they may be subject to a civil penalty for each day in which such violation occurs or failure to comply continues.

Furthermore, after site closure an owner or operator may remain liable under tort and other remedies, or under other federal statutes including, but not li mited to, Clean Air Act, 42 U.S.C. §§ 7401-7671; CERCLA, 42 U.S.C. § 9601-9675; and RCRA, 42 U.S. C. § 6901-6992. EPA does not have authority to transfer SDWA or other legal liabil ity for Class VI wells to the Stat e or federal government or a thirdp arty fund. See the final rule preamble for further discussion of EPA's final approach to financial responsibility for Class VI wells.

Comment: 3. CCS May impact Private Property Rights

Recognizing that subsurface land can be pr ivately owned in the United States, the chamber notes that CO2 injection in to geologic formations may require
p ermission from all owners of intersected subsurface property. While this consideration may be somewhat addressed during the initial siting process, it may still lead to tensions between la rge-scale CCS projects and individual
p roperty rights. The issue beco mes even more important as investors and industry
p articipants will seek to minimize liab ility from property tr espass claims related to sub-surface trespass, geological surveying, and deposit monitoring.

Likewise, property rights considerations may impact the availability of liability insurance for CCS project participants. If insurance companies cannot accurately calculate the risk of CCS projec ts, or future potential environmental liability for property trespass, they may decline to offer coverage.

Response: EPA clarifies that pore space owners hip and surface or subsurface propert y and mineral Commenter Name: William Kovacs Letter ID: 0148 Commenter Or g anization: U.S. Chamber of Commerce Comment ID: 21771rights are outside of the scope of the Class VI GS rulemaking, which fo cuses on ensuring consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA clarifies that these issues are unde r the purview of states and any of these issues, as they relate to GS, will need to be addressed though state regulations. Please see the final rule and
p reamble for additional information on financial responsibility for Class VI GS projects.

Comment: appropriate injection site. Another huge issue which has yet to be broached by EPA is that of property and mineral right s ownership and encroachment. This was cause to slow progress on obtaining an injection permit in Michigan. The EPA Appeals Board ruled that issue was outside the scope of the UIC program but we anticipate this issue will resurface as more sites seek injection permits. Someone has to proactively address this di fficult issue. With all these issues

Response: EPA clarifies that pore space ownership and surface and subsurface property and mineral rights are outside of the scope of the Class VI GS rulemaking, which fo cuses on ensuring consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA clarifies that these issues are unde r the purview of states and any of these issues, as they relate to GS, will need to be addressed though state regulations. Please see the final rule and
p reamble for additional information on financia l responsibility for Class VI projects.

Comment: PROPERTY AND MINERAL RIGHTS

The Property Rights encroachment issue de layed the issuance of an injection
p ermit for the MRCSP small scale injectio n project near Gayl ord, Michigan. The
p ermit was ultimately issued but the topic of property rights was never satisfactorily resolved. Fortunately the small quantity injected in this case did not present a property rights issue an d the case did not go to litigation. Future larger CCS projects may not go forw ard in the absence of resolution of
p roperty rights-related issues. As EEI aptly points out: "Numerous property rights may be implicated by a given CCS project, including ownership interests in the surface property to be used for injection equipment, the subsurface
p roperty housing the injection well, the .pore space. in which CO2 will be stored, and water rights and mineral inte rests that may exist in the area. Currently, an entity interested in pursui ng a CCS project is left to sort out who owns these various interests, an exercise that is a combination of applicable state law--to the extent any applicable state law exists--and sitespecific due diligence. This exercise is likely fraught with considerable uncertainty and expense and must be su ccessfully completed in order for a
p roject to begin." DTE Energy, along with EE, supports further exploration and discussion of these issues, and EPA’s effo rts to solicit public views will serve to raise stakeholder and policy-maker aw areness regarding the importance of their resolution to the successful commercial deployment of CCS. Commenter Name: Skiles Boy d Letter ID: 0160 Commenter Or g anization: DTE Ener gy Comment ID: 21268

Commenter Name: Skiles Bo yd Letter ID: 0160 Commenter Or g anization: DTE Ener gy Comment ID: 21277Response: As described above, EPA clarif ies that pore space ownership and surface and subsurface
p roperty and mineral rights are outside of the scope of the Class VI GS rulemaking. EPA clarifies that these issues are under the purvi ew of states and any of these issues, as they relate to GS, will need to be addressed though state regulations.

Comment: is appropriate. San Miguel also appreciates EPA's recognition that while the new regulations at hand must be within the sc ope of the SDWA, ther e are a number of very important issues (such as long term liability) that are outside the scope of the act but are highly pertinent to deve loping a viable GS pr ogram and we are glad that EPA is willing to discuss these issues as part of this regulatory
p roposal.

Response: EPA clarifies that the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA recognizes the importance of providing clear, fl exible, scalable, and appropriate regulations. EPA believes that the Class VI GS regulation will pr ovide certainty to industr y and the public by providing consistency in requirements across the U.S. and tran sparency about what requirements apply to owners or operators.

EPA notes that long-term liability is outside of the scope of the GS rulemaking and is not addressed in the GS rule. SDWA does not contain any express provisions addressing liability. An owner or operator will be held liable for any pe rmit violations under SDWA §1423.

Under the final GS rule, once an owner or operato r has met all regulatory requirements under Part 146 for Class VI wells and the Direct or has approved site closure pur suant to requirements at §146.93, the owner or operator will ge nerally no longer be subject to enfo rcement for regulat ory noncompliance. Furthermore, their financial inst rument as required under §146.85 will be released if it was not used. However, even if a site closure is approved under §146.93, an owner or operator ma y be held liable for regulatory noncompliance (including violation of 40 CFR 144.12) in certain circumstances. For example, an owner or operator may be held liable for regulatory noncompliance even after site closure was approved if the Director relied on erroneous information (e.g., erroneous modeling data) provided by the owner or operator when approving site closure.

Separate from EPA’s authorit y to enforce regulatory compliance, an owner or operator may be subject to a §1431 response order even after proper site closure is approved under §146.93. Under §1431 the Administrator may require an owner or operator to take necessary response measures if he or she receives information that a contaminant is present or is likely to enter a public water system or an USDW, which may present an imminent and substantia l endangerment to the heal th of persons, and the appropriate State and local authorities have not acted to protect the health of such persons. The action may include issuing administrative orders or commencing a civil action for appropriate relief against the owner or operator of a Class VI well. If the owner or operator fails to comply with the order, they may be subject to a civil penalty for each day in which such violation occurs or failure to comply continues.

Furthermore, after site closure an owner or operator may remain liable under tort and other remedies, or under other federal statutes including, but not li mited to, Clean Air Act, 42 U.S.C. §§ 7401-7671; CERCLA, 42 U.S.C. § 9601-9675; and RCRA, 42 U.S. C. § 6901-6992. EPA does not have authority to transfer SDWA or other le g al liabilit y for Class VI wells to the State or federal g overnment or a thir d

Commenter Name: Joseph Eutizi Letter ID: 0161 Commenter Or g anization: San Mi g uel Electric Cooperative, Inc Comment ID: 21281p arty fund. See the final rule preamble for further discussion of EPA's final approach to financial responsibility for Class VI wells.

Comment: NRECA also appreciate s EPA's recognition that while the new regulations at hand must be within the scope of the SDWA, there are a number of very important issues (such as long term liability) that are outside the scope of the act but are highly pertinent to developing a viable GS program and we are glad that EPA is willing to discuss th ese issues as part of this regulatory proposal.

Response: EPA clarifies that the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA recognizes the importance of providing clear, fl exible, scalable, and appropriate regulations. EPA believes that the Class VI GS regulation will pr ovide certainty to industr y and the public by providing consistency in requirements across the U.S. and tran sparency about what requirements apply to owners or operators.

EPA notes that long-term liability is outside of the scope of the GS rulemaking and is not addressed in the GS rule. SDWA does not contain any express provisions addressing liability. An owner or operator will be held liable for any pe rmit violations under SDWA §1423.

Under the final GS rule, once an owner or operato r has met all regulatory requirements under Part 146 for Class VI wells and the Direct or has approved site closure pur suant to requirements at §146.93, the owner or operator will ge nerally no longer be subject to enfo rcement for regulat ory noncompliance. Furthermore, their financial inst rument as required under §146.85 will be released if it was not used. However, even if a site closure is approved under §146.93, an owner or operator ma y be held liable for regulatory noncompliance (including violation of 40 CFR 144.12) in certain circumstances. For example, an owner or operator may be held liable for regulatory noncompliance even after site closure was approved if the Director relied on erroneous information (e.g., erroneous modeling data) provided by the owner or operator when approving site closure.

Separate from EPA’s authorit y to enforce regulatory compliance, an owner or operator may be subject to a §1431 response order even after proper site closure is approved under §146.93. Under §1431 the Administrator may require an owner or operator to take necessary response measures if he or she receives information that a contaminant is present or is likely to enter a public water system or an USDW, which may present an imminent and substantia l endangerment to the heal th of persons, and the appropriate State and local authorities have not acted to protect the health of such persons. The action may include issuing administrative orders or commencing a civil action for appropriate relief against the owner or operator of a Class VI well. If the owner or operator fails to comply with the order, they may be subject to a civil penalty for each day in which such violation occurs or failure to comply continues.

Furthermore, after site closure an owner or operator may remain liable under tort and other remedies, or under other federal statutes including, but not li mited to, Clean Air Act, 42 U.S.C. §§ 7401-7671; CERCLA, 42 U.S.C. § 9601-9675; and RCRA, 42 U.S. C. § 6901-6992. EPA does not have authority to transfer SDWA or other legal liabil ity for Class VI wells to the Stat e or federal government or a thirdp arty fund. See the final rule preamble for further discussion of EPA's final approach to financial responsibilit y for Class VI wells. Commenter Name: James Stine Letter ID: 0163 Commenter Or g anization: National Rural Electric Cooperative Association (NRECA) Comment ID: 21310Comment: allowed by the director if he so chooses . However, APPA believes that the operation of the power plant should not be stopped if the geologic storage or sequestration is deemed ill advised by the state director (or court). Only the CO2 injection in that location should cease . Instead the owner/operator of that
p ower plant should be allowed to cont inue operations for the purpose of generating electricity (and other functions ) without CO2 injection until either a different technique is deve loped or until infrastructure can be built to move the CO2 to a different in jection location. In some cases, the power plant owner/operator will simply have to make commercial or contractual arrangements to pay a party to take the CO2 for in jection or geoengineering mitigation measures (not yet identified).

Response: The UIC program’s authority under the SDWA focuses on ensuring that Class VI GS
p rojects are permitted, sited, constructed, operated, monitored, and closed in a manner that protects USDWs from endangerment. EPA clarifies that the Class VI GS regulation applies to owners or operators of wells that will be used to inject CO2 into the subs urface for the purpose of long-term storage and does not require any faci lities to capture and/or sequester CO2 and that permitting of power
p lants is outside the scope of the Class VI GS rulemaking.

Comment: In addition, the GAO report discusses the complex and still unresolved property rights issues involving CO2 injection on both federal and nonfederal lands. Id. at 42-23. Finally, GAO cites a National Ac ademy of Sciences ("NAS") report

Response: EPA clarifies that pore space ownership and surface and subsurface property and mineral rights are outside of the scope of the Class VI GS rulemaking. Rather, the purpose of the Class VI GS rule is to ensure that where GS technologies are deployed, GS is performed in a manner that protects USDWs from endangerment. EPA clarif ies that these issues are under th e purview of states and any of these issues, as they relate to GS, will need to be addr essed though state regulations.

Comment: USWAG also urges EPA to issue more defi nitive direction in the Final Rule regarding the regulation of CO2 inj ection activities that cross state boundaries. This issue is ment ioned in the Preamble to the Proposal but receives little attention. See 73 Fed. Reg. at 43497. Rather, EPA simply observes that "some injection activities may raise cros s-state boundary issues that are beyond the scope of this rulemaking." Id. EPA s hould provide more direction regarding how such cross-state activiti es would be regulated, and specifically should make clear in the Final Rule that Owners or Operators of Class VI CO2 GS projects will seek a Class VI permit for that operation from the state in which the wellhead is located. In other words, a given state is the permitting body for any Class VI CO2 GS project with a wellhead in that state. EPA should direct states to consult and coordinate with ot her affected states (i.e., other states Commenter Name: Theresa Pugh Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23400

Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utilit y Solid Waste Activities Group (USWAG) Comment ID: 23470

Commenter Name: James Rowe r Letter ID: 0173 Commenter Or g anization: Utilit y Solid Waste Activities Group (USWAG) Comment ID: 23476to which the underground porti on of the well may extend and/or those to which there could be a subsurface release or migration of injected material) in determining how to avoid duplicative or dueling regulatory syst ems. USWAG urges EPA to play a leadership role and proact ively address these issues by suggesting
p rocedural guidelines for intersta te regulation and cooperation.

Response: EPA acknowledges that CO2 plumes may cross state or even international boundaries and encourages cooperation and coordina tion among permitting authorities. Th e final Class VI GS rule, at §146.82(a)(2), requires the owner or operator to iden tify all State, Tribal, and territorial boundaries within the AoR. Based on this information, the Director must provide written notification to all States, Tribes, and Territories to inform them of the permit application and ensure that they are involved in any necessary processes; this new requirement was added to the final rule at §146.82(b). The Agency encourages transparency in the permitting process and anticipates that State-State/State-Tribal communication on Class VI GS perm itting will facilitate information sharing and encourage safe,
p rotective projects.

EPA clarifies that the Class VI permit would be issu ed by the permitting authorit y in the state where the wellhead is located.

Comment: c. Impact of GS well siting on Underground Natural Gas Storage

As a general matter, EPA should ensure that Class VI permits not inappropriately interfere with other pre-existing s ubsurface interests and operations. Dominion's interest in the rulemaking is from the perspective of both an owner/operator/contractor of CCS and a poten tially affected party as an operator of an extensive network of underground natural gas storage. The sole responsibility of the UIC Program is to provide protections for existing and future USDW. Little protections are af forded for other underground resources, however. The rulemaking unambiguously leaves these concerns to the individual states, irrespective of primacy status. Th e rulemaking's silence with regard to
p rotections for underground natural gas stor age formations is cause for concern to the natural gas industry.

Gas storage operators have particular expertise regarding their natural gas storage fields, and can help prevent pr oblems if EPA helps to ensure their
p articipation in the process of the site evaluation and construction of GS wells in natural gas storage fields. The Agen cy should authorize the Director to ensure the coordination between natural gas storage operators and GS well owners/operators in circumstances wher e the GS construction will occur in natural gas storage fields. Such coor dination can involve, for example, obtaining input from the natural gas storage operators on the unique circumstances associated with the natural gas storage field where the GS well will be constructed. To assist in this process, natural gas storage field operators should have ready access to GS well records, well logs and cementing records for any GS construc tion activity that occurs in a natural gas storage field.

EPA should authorize Directors to en sure coordination between natural Commenter Name: Pamela Fa gg ert Letter ID: 0175 Commenter Or g anization: Dominion Comment ID: 23521gas storage operators and GS well ow ners/operators in circumstances where the GS construction will occu r in natural gas storage fields.

Response: EPA clarifies that pore space ownership and surface and subsurface property and mineral rights are outside of the scope of the Class VI GS rulemaking. EPA clar ifies that these issues are under the purview of states and any of thes e issues, as they relate to GS, will need to be addressed though state regulations. The Class VI GS rule is designed to ensure protection of USDWs from endangerment through proper permitting, siting, well construction, operation, monitoring, and closure of Class VI GS
p rojects.

As part of the permit application process, prospective operators of Cl ass VI GS wells must submit data on other activities subject to envir onmental permitting (e.g., oil or gas fi elds), mines, and a tabulation of all wells in the area of review. This informati on, including data on any other injection or production activities in the area would be taken into consideration by the Director in ev aluating the appropriateness and safety of the proposed site.

Comment: 8. Other Issues Outside the Scope of the Rulemaking

An area of concern to the gas storage industry is the expansion of the UIC
p rogram. To date, the injec tion of hydrocarbons for purposes of storage has been excluded from federal regulation under the UIC program. If EPA sees fit to establish a new category of well for the purpose of injecting CO2 for storage, it should be made clear that this program will not af fect storage of natural gas. This concern is more pronounced as th e industry expands its use of CO2 as a base gas for underground storage of natural gas.

The establishment of a new class of well for geologic sequestration of CO2 should not include expanding the UIC program generally to incorporate underground natural gas storage.

Response: EPA clarifies that the Class VI GS requirements apply only to wells that are injecting CO2 into the subsurface for the purpose of GS, and not to natural gas storage operations. EPA clarifies that developing specific requirements for natural gas st orage operations is out of the scope of the UIC
p rogram's authority. However, EPA notes that the fi nal rule requires Class VI permit applicants to submit maps and tabulations of wells, including injection wells (which could be used for ER or natural gas storage), in the AoR for review by the UIC pr ogram Director. In addition, the rule requires the Director to notify the state oil and gas agency and state mineral explorat ion and recovery agency as part of the public notification require d for a draft permit (§ 124.10(c)(1)(xi)). EPA expects that these agencies will inform the Director of any existi ng natural gas storage facilities around the proposed Class VI GS site and that the Director will take this information and the data on wells in the AoR into consideration when deciding whether to grant a permit for the Class VI well.

Other EPA Comment Codes and Descriptions: 2100 1.6 Target Geologic Formations for GS; 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83); 3120 2.1.2 Need to identify additional confinin g and containment zones (seekin g comment) Commenter Name: Pamela Fa gg ert Letter ID: 0175 Commenter Or g anization: Dominion Comment ID: 23533

Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23551Comment: EEI agrees that proper site selection is cr itical to a successful GS project and notes that it serves to minimize, if not eliminate, any potential threats to drinking water sources th at CO2 injection and storage may pose. However, several of the proposed requirements are unnecessary from the perspective of
p rotecting drinking water sources and would only serve to hamper GS projects from going forward, including limitations on receiving formations, potential alteration to the current definition of an underground source of drinking water (USDW), and the proposed grant of discretion to the UIC program director to require permit applicants to identify secondary containment/confining zones.

Response: EPA retains the requirement to identify additi onal containment/confining zones, if required by the Director, as proposed (§146.83(b)). EPA acknowledges that such additional zones may not be needed in all circumstances, and clarifies that this requirement is at the Di rector's discretion, based on his or her understanding of a particular site. EPA beli eves that, in some situations, the presence of additional confining and containment zones above th e primary (i.e., lowermost) confining zone can improve USDW protection. These laye rs could further impede vertical fluid movement and allow for
p ressure dissipation, and also provi de additional sites for monitori ng, mitigation, and remediation. The Agency's decision is supported by commenters represen ting states, water associat ions, and an electric utility who assert that these requi rements promote a flexible, risk-b ased, site-specific approach to characterizing and permitting a site for GS project s, and are intended to improve understanding of the
p roject as a whole and promote better modeling of the site.

EPA believes that the Class VI requirements, including the level of site ch aracterization required under §§146.82 and 146.83, appropriately address the unique ch allenges posed by large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the
p otential presence of impurities in captured CO2, and its mobi lity within subsurface geologic formations.

EPA disagrees with the commenter that the GS ru le requirements are unnecessary to protect USDWs. The GS final rule builds upon l ongstanding programmatic requirement s for underground injection that have been in place sinc e the 1980s and that are used to mana ge over 800,000 injection wells nationwide. These programmatic requirements ar e designed to prevent fluid movement into USDWs by addressing the potential pathways through which injected fluids can migrate into USDWs. EPA coordinated with Federal and non- Federal entities on GS and CCS to determine how best to tailor existing injection requirements to CO2 for GS.

Additionally, EPA clarifies that the GS rule does not categorically preclude injection of CO2 into any non-USDW formation types. The purpose of the GS rule is to ensure protection of USDWs from endangerment, and the rule requires that owners or operators demonstrate that wells are sited in suitable systems with geologic formations to receive and confine injected CO2, required at §146.83 of the GS rule. The Class VI siting, well construction and operation, monitoring and testing, and post-injection site care and site closure requirements ar e designed to ensure that injected CO2 remains within the target formation. If an owner or operator can demonstrate to th e Director's satisfaction th at GS in coal seams, b asalts, salt domes, or shales can be accomplished in a manner that protects US DWs and meets all of the requirements of the GS rule, the project may be permitted as a Class VI well.

Comment: Further, althou g h EEI appreciates that issues related to propert y ri g hts and Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23575p ore space ownership that may be associ ated with injection and storage are outside the scope of the Agency‘s rule making, comments are provided on these issues as well, at th e Agency‘s request.

Response: EPA clarifies that pore space ownership and surface and subsurface property and mineral rights are outside of the scope of the Class VI GS rulemaking, which fo cuses on ensuring consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA clarifies that these issues are unde r the purview of states and any of these issues, as they relate to GS, will need to be addressed though state regulations.

Comment: K. Issues Related to Potentia lly Implicated Property Rights

Finally, although EEI recognize s the limits on EPA‘s jurisdiction regarding CCS
p rojects, our members appreciate the Agen cy raising for public comment issues related to property rights that may be associated with CO2 injection and storage. While the importance of EPA‘s rulemaking as an important step in
p roviding clarity, flexibility and certainty for project operators and investors cannot be overstated, CCS projects may not go forward in the absence of resolution of property rights-related issues.

N umerous property rights may be implicated by a given CCS project, including ownership interests in the surface property to be used for injection equipment, the subsurface property housing the injection well, the "pore space" in which CO2 will be stored, and water rights and mi neral interests that may exist in the area. Currently, an entity interested in pursuing a CCS project is left to sort out who owns these various interests, an exercise that is a combination of applicable state law--to the extent any applicable state law exists--and sitespecific due diligence.[FN15] This exercise is likely fraught with considerable uncertainty and expense and must be su ccessfully completed in order for a
p roject to begin. Commercial deploymen t of CCS technology may be advanced considerably through legal mechanisms at the state and federal levels that assist potential permittees in worki ng through property rights-related issues. Available mechanisms may range from laws that clarify presumptions related to ownership of various implicated interests [FN16] to provisions allowing for use of eminent domain authority to obtain such interests. EEI supports further exploration and discussion of these issues , and EPA‘s efforts to solicit public views will serve to raise stakeholder and policy-maker awareness regarding the importance of their resolution to the successful commercial deployment of CCS.

[FN15] The proposed regulations would also require the permittee to record a notice on the deed (or other relevant doc ument) to the "faci lity property" containing certain information. While EEI is not opposed to the concept of a deed notice, more clarity is needed in the regulations regard ing how "facility
p roperty" is to be defined in order to better understand the scope of the
p roposed requirement. EEI recommends limi ting "facility property" to the area immediately surrounding th e injection well. Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23608[FN16] See Wyoming‘s House Bill 89, http://legisweb.state.wy.us/2008/Enroll/H B0089.pdf, which became law in July 2008.

Response: As described above, EPA clarif ies that pore space ownership and surface and subsurface
p roperty and mineral rights are outsi de of the scope of the Class VI GS rulemaking, which focuses on ensuring consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

EPA recognizes the importance of providing clear, fl exible, scalable, and appropriate regulations. EPA believes that the Class VI GS regulation will pr ovide certainty to industr y and the public by providing consistency in requirements across the U.S. and tran sparency about what requirements apply to owners or operators.

Other EPA Comment Codes and Descriptions: 1300 1.1.2.3 Comments on other aspects of CCS (capture, transport); 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 Comment: XII. RELATED ISSUES, NOT RAISED IN THE PROPOSED RULE, THAT REQUIRE RESOLUTION

The SDWA does not provide EPA authorit y to develop regulations for many important areas related to the geological sequestration of CO2. Thus the draft rule cannot address all of the potential im pediments to CCS development. Even if EPA were to promulgate a final UIC rule that encourages development of these critical technologies, there are other ke y factors that would need to be
p roperly addressed before major investme nt in these technologies can be expected.

The following sets forth key issues that will not be resolved through this rulemaking but are linked inextricably to the successful development and implementation of CCS technology.

A. EMINENT DOMAIN AUTH ORITY TO FACILITATE PI PELINE CONSTRUCTION

Energy facilities for the public convenien ce and necessity, such as electric transmission facilities and natural gas pipelines, are able to make use of state or federal eminent domain authority to ensure that private landowners cannot block a project necessary for the public good. Eminent domain authority should be available for CO2 pipelines for CCS wh en it is necessary to cross private
p roperty. A substantial CO2 pi peline network may be re quired for the transport of CO2 from sites where it is produced to an injection site. CO2 pipelines for CCS clearly should be consid ered to be used for the public convenience and necessity.

B. DETERMINATION OF SUB-SURFACE PROPERTY RIGHTS

The government must address the ability to gain sufficient property rights to deep saline form ations to conduct g eolo g ic sequestration. State propert y Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23877ownership regimes vary, but surface owners typically are considered to own
p roperty below the surface to the center of the earth. Safe sequestration of CO2 will not have any effect on the surface, but GS injections will result in underground plumes that may stretch across many square miles under the property of multiple surface prope rty owners. Propert y ownership issues have been resolved successfully in the context of EO R, but it should not be assumed that the same will be true for GS. Eminent domain authority should be available to obtain rights to subsurface storage space for geologic sequestration because of its public benefit.

C. RESOLUTION OF SURFACE LIABILITY ISSUES

Though this Proposed Rule is limited in its scope to undergr ound injection of CO2 and the potential risks and resulting liabilities, issues regarding risks and liability at the surface must be addressed for CCS t echnology to fully develop. These include liability for majo r and sudden releases, seismic activity and ground heave, as well as liability under any GHG emission control regime when sequestered CO2, for the storage of which credits or offsets have been granted, is subsequently releas ed into the upper atmosphere.

Response: EPA acknowledges that the issue of GS falls within the broader context of CCS. EPA received a number of comments indi cating that the Agency should further explore environmental and regulatory issues beyond the scope of the GS rule as proposed. This comment is outside the scope of this rulemaking.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

EPA recognizes that liability is an important issue to owners or opera tors but the Agency does not have authority under the SDWA to transfer long term liability from owners or operators to the state or federal government. Therefore, liability remains with the owner or operator.

Other EPA Comment Codes and Descriptions: 1610 1.3.1 Risks to USDWs Comment: Assignment of Liability: Most important ly, the regulation does not seem to address the liability that w ould be realized by owners/ operators of the geologic sequestration projects if water quality of USDWs is degraded by the operation of their pro j ect (even if the impacts are limited to MCLs). AW WA recommends that Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23664this issue be addressed in the final regulation, as dr inking water utilities may have little financial recour se if the water quality one of their aquifers is degraded due to the operation of a geol ogic sequestration process. Provisions need to be included in the final rule that would allow the drinking water utility to recoup any costs that are r ealized due to increased treatment requirements for contaminated ground water or to replace lost capacity. In some cases, utilities may need to install diff erent types of treatment to remove compounds that might not have been present in the water prior to the geologic sequestration project. In othe r instances, treatment may consist of the addition of more chemicals to facilitate precipi tation of the inorganic compounds or the utility may have to backwash membranes more often, resulting in higher energy and other operation and maintenance co sts. In any of these cases, the owner/operator of the geologic sequest ration project should be required to reimburse the drinking water utility for th ese incurred costs, and they should also be required to continue such pa yments for as long as the ground water source remains degraded.

Water utilities should not be penalized for having to develop local sites contaminated by sequestration activities fo r water supply. In fact they should be encouraged to do so, under the appropriate conditions, as there is no more critical public health issue than the need to provide potable water. In order to meet increasing demands im posed on them by a growin g service population, water utilities will need to develop marginal water supplies. However, increased treatment costs due to contamination resulting from sequestration activities should not be borne by the local utilit y or their customers when national environmental objectives have been met wi thout significant benefit to the local
economy.

Should a water utility "lose" an existi ng or future source of supply due to contamination or inaccessibility resulting from a sequestration project, there will be the issue of financial compensati on (for treatment or development of an alternative source). As water resources become scarce, financial compensation for a lost source of supply may not suffic e, as local alternatives may not be available. Hence, it will be critical that contingency planning to identify alternatives to the current groundwater supply be a part of the planning activities for the sequestration project, along with a commitment to provide an alternative source of water, should the need arise.

Response: EPA agrees that owners or operators of Class VI wells must ensure that resources are available to prevent endangerment of USDWs from improper plugging, remediation, and management of wells. For this reason, the GS rule requires th at owners or operators demonstrate and maintain financial responsibility for corrective action on well s in the AoR, injection well plugging, post-injection site care and site closure, and emergency and remedial response at GS sites as specified in §146.85. In the event of contamination or ot her adverse event to the USDW during the life of the project, the financial instrument(s), such as insurance, bonds, etc., rather than public monies, would cover necessary response actions. EPA clarifies that it is the owner or operator of th e well who will be required to demonstrate financial responsibility, not the genera tor of the CO2, consistent with EPA’s authority under SDWA. Furthermore, EPA notes that tort and other remedies will continue to be available after site closure. Other Federal environmental st atutes, e.g. Clean Air Act, 42 U.S.C. §§7401-7671; CERCLA, 42 U.S.C. §9601-9675; and RCRA, 42 U.S.C. §6901-6992, potentially apply as well to the risks created by the long-term stor age of CO2. EPA has also examined potential methods for conductingtreatment of water affected by a CO2 leak; this study is pr esented in the final rulemaking docket.

EPA clarifies that long-term liability beyond the life of the project (after site closure) is beyond the scope of the GS rulemaking. Please see the final rule and the discussion of fi nancial responsibility and long-term liability in the preamb le for additional information.

EPA adds that Class VI well owners and operators mu st site, construct, operate , monitor, and close their wells in a manner that protects USDWs, and Class VI permits will set forth rigorous technical requirements to ensure careful planning, operation, and closure of GS projects. Failure to meet these requirements would be consid ered a violation of the pe rmit and would be subject to applicable civil, criminal, or administrative penalties under SDWA §1423.

Comment: AWWA also recommends that the compa ny generating the carbon dioxide must maintain sole ownership of the carbon dioxi de they generate. This would ensure that liability remains with the original generator in perpetuity; even if the carbon dioxide is commingled with some gene rated from another facility or if its disposal is managed by another company.

Response: EPA clarifies that the final Class VI GS rule appl ies to owners or operators of wells that will be used to inject CO2 into the subsurface for the pur pose of long-term storage, and not the generator of the CO2. Any issues related to "ownership" of genera ted CO2 are outside the scope of the Class VI GS rulemaking. Rather, the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: Project Security: AWWA recommends that EPA work with the Department of Transportation and the Department of Homeland Security to ensure the safety and security of geologic sequ estration projects. We have concerns about the unintentional or intentional release of stored carbon dioxide and the related control and monitoring systems required, as well as security measures. A requirement for strict m onitoring systems during project construction and operation is necessary to ensure that the project is not intentionally sabotaged, as this could result in a massive leak of carbon dioxide out of the confinement zone and into the environmen t. EPA should mandate strict monitoring systems be included as part of any geologic sequestration project, not only to ensure the safety of USDWs, but also the safety of those living in the footprint of the project.

Response: EPA clarifies that pipelines an d CO2 transport are outside the scope of the Class VI GS rulemaking. The Class VI GS regulation is being promulgated under authority of the Safe Drinking Water Act. The purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in antici pation of the eventual use of GS to reduce CO2 emissions.

Re g ardin g the comment on ensurin g the safet y and securit y of GS pro j ects related to unintentional or Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23665

Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23674intentional release of stored CO2, EPA clarifies that the purpose of the Cla ss VI GS rule is to ensure that where GS technologies are deployed, GS is perf ormed in a manner that protects USDWs from endangerment. EPA agrees that testing and moni toring are important aspects of ensuring USDW
p rotection, and the Class VI GS rule requires that owners or operators develop and implement a testing and monitoring plan. See the final rule and preambl e discussion of testing a nd monitoring requirements for additional information.

Other EPA Comment Codes and Descriptions: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 CFR 146.85) Comment: Category: Financial

EPA Request for Comment: Because of the po ssibility that the owner or operator may face financial distress prior to the trust being fully funded, EPA is considering a guidance approach that woul d recommend adopting a pay in period of three years for GS projects, consistent with other similar programs in the Agency. EPA Notice 43521.

EPA is assessing whether to provide guidance on the use of insurance providers and, if so, whether to update eligibility requirements for insurers for GS wells consistent with other current Federa l agency practices. EPA Notice 43521.

EPA is requesting comments on whether fina ncial responsibility mechanisms to be recommended in EPA guidance should be adju sted in the manner described, whether additional instruments should be included, and whether other adjustments to the financial responsibility mechanisms shoul d be considered, all subject to EPA’s authority under the SDWA. EPA Notice 43522.

AWWA Response: AWWA has several majo r concerns regarding owner/operator financial assurance and liability. Our pr imary concern is that the liability mechanism that would be triggered when the confining zone fails and carbon dioxide escapes has not been identifie d. Would this incident trigger CERCLA requirements if groundwater is degraded? AWWA recommends that the liability requirements and financial mechanisms that were used to address MTBE contamination be applied to any USDW degradation from carbon sequestration activities. The definition of a "corrective action" does not provide any
p rotection for aquifers that are contaminated by the carbon sequestration
p rocess. The definition as provided in the proposed rule states that corrective action is "...the use of Director approved methods to assure that wells within the area of review do not serve as condui ts for the movement of fluids into underground sources of drinking water (USDW)." Note th at this definition does not address "fixing" the impact to USDW. What is unclear to AWWA is if the geologic sequestration proces s does endanger groundwater aquifers, whether the owners/operators have any financial liab ility in restoring water quality (e.g.,
p aying for extra treatment costs incu rred by water utilities or other groundwater users), as the corrective act ion seems to focus on fixing injection wells and/or the confining layer.

The question remains re g ardin g what an owner/operato r ’s total liabilit y would be Commenter Name: Thomas Curtis Letter ID: 0181 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 23707outside of the USDW contamination. The pot ential exists for contamination of other ground water aquifers, su ch as those that are not classified as USDWs but are used as a drinking water sources, a nd it is extremely im portant that the liability requirements are extended to these aquifers. The cost to remediate any degradation can be extremely high. Depe nding on the scope and location of the degradation, examples of po tential costs that might be incurred by a drinking water utility include the installation of advanced water trea tment technologies and/or development of alternative wate r sources. The responsibility for these costs must be assumed by the owner/operat or in the event of a failure of the geologic sequestration process.

AWWA believes that the time limit for financial responsibility in the proposed regulation may be too long for most insurance agencies, which may trigger the need for the development ofa trust fund or for owner/operators to use a selfinsurance mechanism. If the trust fund is the desired method, EPA should require that companies constantly add to the fund, even if it appears that the fund is fully funded. In addition to the initia l pay in period of three years, owner/operators should be required to pa y in any additional amount identified during the five-year reviews for the area of review and corr ective action plan, injection well plugging plan, the post-injection site care a nd site closure
p lan, and the emergency and remedial res ponse plan. This additional pay in is required so that we don't have a repeat of the funding stoppage with the Superfund program.

Response: The goal of financial responsibility is to ensu re that financial resources are available to
p revent endangerment of USDWs fr om improper plugging, remediation, and management of wells in the event that the owner or operator experiences financial difficulties. As such, owners or operators must demonstrate financial responsibility for, among ot her things, any needed emergency and remedial response actions that are necessary to mitigate e ndangerment or potential endangerment of USDWs. See the final rule and preamble for fu rther discussion of EPA's final appr oach to financial responsibility.

EPA clarifies that, while the commenter accurately de fines corrective action for wells in the AoR, this term does not refer to actions needed to addre ss endangerment in the UIC program regulations. EPA clarifies that the intent of the emergency and remedial response requirements at §146.94 is that if the owner or operator obtains any evidence that USDWs may be endangered, he or she must cease injection, take all steps reasonably necessary to identify a nd characterize any release, notify the Director, and implement the approved emergency and remedial response plan, per §146.94(b).

EPA disagrees that GS is analogous to the MTBE situation. EPA be lieves that large scale GS can be done safely. The GS regulation builds upon the long-standing, protective regulat ory framework of the UIC program, which has been regulating the injection of fluids for decades. The GS regulation enhances this existing framework with tailored requirements for Class VI GS wells to address the unique nature of large scale GS of CO2. Th ese protective requirements include extensive geologic testing, detailed computational modeling of the AoR and periodic re-evaluations, deta iled requirements for monitoring and tracking the CO2 plume and pressure front, and extended post-injection moni toring and site care.

Comment: II. Ensurin g the Lon g -Term Containment of CO2 at Sequestration Sites Commenter Name: Wend y Jacobs Letter ID: 0183 Commenter Or g anization: Harvard Law School Environmental Law and Policy Cente r Comment ID: 25142A. EPA Should Require Owners or Operators to Demonstrate that CO2 Will Be Contained for the Long-Term

The purpose of GS is to store anthro pogenic CO2 for the "long term." See 73 Fed. Reg. at 43,535 (proposed 40 C.F.R. § 146.81) (defining "geologic sequestration" as the "long-term c ontainment of a gaseous, liquid or supercritical carbon dioxide stream in subs urface geologic fo rmations"). If-but only if-the sequestered CO2 is containe d (i.e., not allowed to escape into the atmosphere) for a sufficiently long pe riod of time will CCS fulfill its
p otential to be "a key mitigation t echnology for achieving domestic emissions reductions" and "help to mitigate climate change." 73 Fed. Reg. at 43,492, 43,496. As drafted, however, the proposed regulation fails to tackle the question of how long is "long term."

EPA should provide a sense of the time scales involved and require owners/operators to make a reasonable de monstration that the injected CO2 will not migrate in such a way that will frustrate the broader climate change related goals of GS, lead to human enda ngerment, or threaten USDWs.

Despite the fact that long-term contai nment is critical to the success of a climate change mitigation program and to satisfy the public protection mandate of the SDWA, EPA’s proposed GS regulation fails to require perm it applicants to demonstrate that long-term containment wi ll be achieved and maintained. In this respect, the proposed rule is less stringe nt than the requirements for Class I hazardous waste injection wells, which requi re the permit applicant to show to a reasonable degree of certainty that no ha zardous materials will migrate from the injection zone for 10,000 years.[FN3] 40 C. F.R. § 148.20(a)(1)(i). The differences between hazardous waste and CO2 suggest that a 10,000 year demonstration may be too stringent for GS within Class VI wells, but the existence of a 10,000 year demonstration standard for Class I wells confirms that EPA can reasonably impose and administer a reasonable demonstration standard for Class VI wells.

[FN3] In the alternative, the owner or ope rator may demonstrate that, "[b]efore the injected fluids migrate out of the injection zone or to a point of discharge or interface with USDW, the fluid will no longer be hazardous because of attenuation, transforma tion, or immobilization of haza rdous constituents within the injection zone by hydrolys is, chemical interactions or other means . . . ." 40 C.F.R. §148.20(a)(1)(ii).

In its regulations for GS of CO2, Washingt on State requires GS permit applicants to demonstrate to a high de gree of confidence that "substantially ninety-nine
p ercent of the greenhouse gases will rema in contained for at least one thousan d years." Wash. Admin. Code §§ 173- 218-115(4)(a)(i)(A), 173-407-110 (2008). Though Washington’s one thousa nd year requirement seems consistent with the timescales imagined in EPA’s preambl e, see 73 Fed. Reg. at 43,496 (total GS capacity is expressed as th e ability to sequester CO 2 emissions for "hundreds, if not thousands" of years), no comparab le requirement is imposed on a permit applicant under EPA’s proposed regulation fo r Class VI wells (or on the owner or operator during the construction, inject ion, post-site injection care, site closure, and post-closure phases of a GS project). See id. at 43,536-37,43,537-41 (proposed 40 C.F.R. §§ 146.82-.84, 146.86-.94).[FN4]

Given the central importance of "long-term " containment to any GS project, EPA should add a long-term containment demonstration requirement to the proposed regulation. At a minimum, a permit applicant should be required to demonstrate long-term containment as a precondition to being issued an injection permit, similar to the requirement in the Cla ss I UIC program and Washington State’s GS regulation.[FN5] ELPC and ETIP recommend adopting a 1,000 year containment standard.

[FN4] Texas imposes a demons tration requirement similar to Washington State as a condition for tax exemptions to enc ourage GS. Tex. Tax Code Ann. § 202.0545(d) (1)(2007) ("The operator’s planned sequest ration program will ensure that at least 99 percent of the carbon dioxide seque stered . . . will remain sequestered for at least 1,000 years.").

[FN5] EPA also should consider requiring the owner or operator to demonstrate long-term containment again as a precondi tion to granting site closure, and/or
p eriodically during various ph ases of the GS project.

Response: EPA clarifies that setting a "confinement standard " is outside the scope of the Class VI GS rulemaking. However, the Class VI GS rule requires th at CO2 injected for GS remain confined in the injection zone. Leakage outside of the injection zone/to the surface would be a permit violation. The
p urpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United St ates and provide require ments to prevent enda ngerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

Comment: While NiSource will readily agree that there are many differences between storage of natural gas and geologic sequest ration of CO2, NiSource submits that there are a number of technical and comm ercial similarities in addition to lessons that can be applied from deca des of injection and control of high
p ressure natural gas. These similarities include technical issues, securing mineral rights, landowner relations, coexis ting with third part y development of the surface and subsurface, and a wide range of regulatory and commercial aspects. The following points summarize four primary lessons learned through

Response: EPA recognizes that the oil and gas industry has decades of experience injecting CO2 and has demonstrated the effectiveness of many of the te chnologies that will be employed at GS sites. The Class VI GS rule builds on this expe rtise with requirements tailored to the unique issues associated with GS through proper permitting, siti ng, well construction, operation, monitoring, and closure of GS
p rojects. However, EPA clarifies that pore space issues are outside the scope of the Class VI GS rulemaking. EPA clarifies that these issues are under the purvi ew of states and any of these issues, as they relate to GS, will need to be addressed though state regulations.

Comment: aspects. The followin g points summarize four primar y lessons learned throu g h Commenter Name: Daniel Plath Letter ID: 0188 Commenter Or g anization: NiSource, Inc. Comment ID: 25228

Commenter Name: Daniel Plath Letter ID: 0188 Commenter Or g anization: NiSource, Inc. Comment ID: 25231operation of natural gas storage that would be applicable to GS:

3. NiSource subsidiaries' experience is that it is impossibl e to obtain 100% agreement from thousands of landowners on the development of their subsurface for virtually any activit y even with numerous public meeting, private discussions, newsletters, etc. For GS to be utilized beyond the pilot project scale, this issue must be addressed. While this topic is not directly within the scope of EPA and this Proposed Rule, EPA' s requirements can have an impact on the degree and extent to which a potential operator will have to interfere with a landowner. That will directly impact a landowner's willingness to accept GS on their property. Excessive MMV regulations can cause the landowner to have an incorrect perception as to the sa fety of GS under their property.

Response: As described above, pore space i ssues are outside the scope of the Class VI GS rulemaking. EPA clarifies that these issues are under the purview of states and any of these issues, as they relate to GS, will need to be addres sed though state regulations.

EPA acknowledges that CO2 plumes may cross state or even intern ational boundaries and encourages cooperation and coordination among pe rmitting authorities. The final Class VI GS rule, at §146.82(a) (2), requires the owner or operator to identify al l State, Tribal, and Territ orial boundaries within the AoR. Based on this information, the Director must provide written notif ication to all States, Tribes, and Territories to inform them of the permit applicati on and ensure that they are involved in any necessary
p rocesses; this new requirement was added to the final rule at §146.82(b). The Agency encourages transparency in the permitting process and anticipa tes that State-State/State-Tribal communication on Class VI permitting will facilita te information sharing and encour age safe, protective projects.

Comment: Associated with the State primacy i ssue is how to address cross-state boundaries. We feel that some injection activities will cross State boundaries and that the State in which the well head is located should consult and coordinate with the other impacted St ate(s). Duel or duplicative regulatory systems will only unnecessarily burden poten tial injection proj ects limiting the value of this overall program. A final aspect for the states will be the

Response: EPA acknowledges that CO2 plumes may cross state or even international boundaries and encourages cooperation and coordina tion among permitting authorities. Th e final Class VI GS rule, at §146.82(a)(2), requires the owner or operator to identify all State, Tribal, and Territorial boundaries within the AoR. Based on this information, the Director must provide written notification to all States, Tribes, and Territories to inform them of the permit application and ensure that they are involved in any necessary processes; this new requirement was added to the final rule at §146.82(b). The Agency encourages transparency in the permitting process and anticipates that State-State/State-Tribal communication on GS permitting will facilitate information shari ng and encourage safe, protective
p rojects.

EPA clarifies that the Class VI permit would be issu ed by the permitting authorit y in the state where the wellhead is located. Commenter Name: Paul Pike Letter ID: 0198 Commenter Or g anization: Ameren Corporation Comment ID: 23940

Commenter Name: John Corra Letter ID: 0205Comment: 3. Permit Fees: The US EPA should consider a permit fee formula for Class VI wells that is sufficient to support st ate, tribal, and permitting programs,
p rovides consistency of fee amounts between such programs, and provides certainty of fee expenses to those interested in or applying for a Class VI
p ermit.

Response: EPA clarifies that it does not ha ve authority to set pe rmit fees for Class VI well owners or operators under SDWA.

EPA recognizes that states may face technical and administrative challenges including resource concerns, and will work closely with the states to as sist them in resolving funding issues or acquiring the resources, personnel, and training needed to address the unique technical challe nges associated with GS. EPA will also incorporate Class VI GS wells into the UIC program's grant allocation process. The States/Tribes/Territories must also demonstrate that they have ade quate resources to implement the
p rogram through matching resources against those allocated by the UIC program's grant allocation formula. Currently, primacy programs are require d to meet a minimum of 25 percent matching requirement.

Other EPA Comment Codes and Descriptions: 1610 1.3.1 Risks to USDWs; 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) Comment: - The USDW classification must be reconsid ered when siting Class VI wells. The best sources of drinking wate r are already being used by utilities. Coupled with challenges resulting from climactic changes, populat ion growth and land development, many utilities are turning to more challenging groundwater sources such as those that are very deep or ha ve high salinity concentrations, also because the pumping costs for these deep wells are no longer prohibitive given the lack of sufficient water elsewhere. Some of these new sources could fall outside of the current defi nition of a USDW, in that the aquifer has a TDS concentration higher than 10,000 ppm. EPA’s proposed rule promises protection of USDWs from endangerment yet there are no anti-degradation provisions in the
p roposed regulation to protect other gr oundwater supplies, such as those aquifers that are not classified as a USDW but have been, or may be, identified as a future drinking water source. The TDS criterion was written at a time when many advanced water treatment technologies were generally cost prohibitive. In light of the changes in the hydrologi cal and technological landscape, we recommend that EPA reexamine the classification of USDWs based on TDS when considering the siting of Class VI geoseque stration wells. The pot ential need to use saline aquifers for potable supply, pa rticularly in water-stressed areas, should take precedence over the seque stration of carbon dioxide there.

Response: The Agency acknowledges commenter concerns about water resources and future water resource availability. However, modifying the definition of a USDW is outside the scope of the GS rulemaking. USDWs are defined as aqui fers currently being used as s ources of drinking water or those capable of supplying a public water system and they have a total dissolved solids (TDS) content of 10,000 milli g rams per liter or less (§144.3). Commenter Or g anization: Wyoming Department of Environmental Quality (DEQ) Comment ID: 22191

Commenter Name: Diane VanDe Hei Letter ID: 0206 Commenter Or g anization: Association of Metropolitan Water Agencies (AMWA) Comment ID: 22209The primary goal of the UIC Program under the SDWA is to protect USDWs in order to ensure a reliable supply of drinking water for the American public. The GS rule, as part of the UIC program regulations, continues the program’ s tradition of ensuring the prot ection of USDWs. The permitting, siting, construction, operation, monitoring, and post-injec tion site care requirements in the GS rule built on a long-standing protective regulator y framework, tailored to the unique characteristics of CO2 GS.

Comment: INJECTION ACTIVITIES THAT CROSS STATE BOUNDARIES

In view of the likelihood that CO2 inje ction activities on GS projects will cross state boundaries, Duke Energy joins ot her stakeholders in urging EPA to reconsider its position of not addressi ng cross-state boundary issues in this rule-making. Instead, EPA should provide di rectives to states and corresponding certainty to owners and operators of GS projects when the AoR crosses state lines. At a minimum, the Final Rule shoul d provide that the state in which the well head is located should be the prim ary state for purposes of permitting the Class VI well for GS of CO2. EPA should also direct the primary state to consult, coordinate and coope rate with each state within the AoR. The Final Rule should establish guidelines for the cons ultation, coordination and cooperation between the primary state and ach state within the AoR.

Response: EPA acknowledges that CO2 plumes may cross state or even international boundaries and encourages cooperation and coordina tion among permitting authorities. Th e final Class VI GS rule, at §146.82(a)(2), requires the owner or operator to identify all State, Tribal, and Territorial boundaries within the AoR. Based on this information, the Director must provide written notification to all States, Tribes, and Territories to inform them of the permit application and ensure that they are involved in any necessary processes; this new requirement was added to the final rule at §146.82(b). The Agency encourages transparency in the permitting process and anticipates that State-State/State-Tribal communication on Class VI permitting will facilitate information shar ing and encourage safe, protective
p rojects.

EPA clarifies that the Class VI permit must be issu ed by the permitting authorit y in the state where the wellhead is located pursuant to UIC regulations.

Comment: Tampa Electric acknowledges the EPA's not e that the proposed SDWA underground injection regulations do not provide th e EPA with authority to develop regulations for all areas relate d to carbon sequestration, including "determining property rights (i.e., to perm it its use for [carbon sequestration] and for possible storage credits) [and] transfer of liability fr om one entity to another", but feels that parts of this re gulation can be constructed so as to
p rovide important guidance in further st atue and regulatory development as related to these issues. Of main impor tance in this part icular regulation development, if the Federal government be lieves this type of regulation is necessary, then it is Tampa Electric's recommendation to EPA to include a declaration that the activit y of CCS is of hi g h public importance. If and when Commenter Name: Michael Stroben Letter ID: 0209 Commenter Or g anization: Duke Ener gy Comment ID: 22686

Commenter Name: Paul L. Carpinone Letter ID: 0212 Commenter Or g anization: Tampa Electric Company Comment ID: 22901storage of carbon dioxide is deemed a public necessity by the EPA, for the occasion that a CO2 injection well may be located adjacent to property owned by another party, the Final Rule may incl ude verbiage analogous to underground natural gas storage eminent domain powers or oil and gas unitization processes for acquisition of pore space of a geol ogical formation. Also, the EPA may consider providing guidance similar to that of the "negative rule of capture" for secondary oil recovery operations (water flooding), which provides that less valuable substances injected into a geol ogical formation may mi grate and replace more valuable substances wi thout resulting liability.

Response: EPA clarifies that eminent domain, pore space ownership, and surface and subsurface
p roperty and mineral rights are outside of the scope of the Class VI GS rulemaking. EPA clarifies that these issues are under the purvi ew of states and any of these issues, as they relate to GS, will need to be addressed though state regulations. EPA also notes that carbon crediting and green house gas accounting are outside the scope of the Class VI GS rulemaki ng. The Class VI GS rule is designed to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and
p rovide requirements to pr event endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

However, the Agency acknowledges that these issues are important and is addressing them using other regulatory authorities. For example, in a separate ru lemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Gas Reporting Program at 40 CFR Part 98 to add reporting requirements for CO2 injection and GS. The greenhouse gas re porting requirements build on the requirements outlined in the Class VI GS rule with the additiona l goals of verifying the amount of CO2 sequestered and collecting data on any CO2 emissions to the surface from GS facilities.

Comment: We would also call to EPA’s attention ot her recent research from the GHGT-9 Conference that is relevant to this rulema king with regard to the carbon content of oil that could be produced via CO2 injection of captured CO2 emissions. Ferguson, et al. reviewed the net carbon c ontent of oil produced via CO2-based EOR, taking into account the storage of residual CO2 that remains stored as a normal incident of EOR production operati ons. The researchers calculated that oil produced through injection of capture d CO2 emissions would be roughly 70
p ercent "carbon free" under current technol ogy. See Ferguson, Nichols, Leeuwen, and Kuuskraa, "Storing CO2 with Enhanced Oil Recovery" ("Ferguson, et al. 2008") [FN34] The authors estimate that next generation CO2 stor age technology may allow for the produced oil to be "100+ " percent carbon free and evaluate the
p otential size of the market for CO2 for these EOR purposes on the order of 7,500 million metric tonnes between now a nd 2030. This capability of the U.S. oil industry to reduce the net carbon conten t of new oil supplies is an aspect of the sequestration debate that is not addressed in the Proposed Rule, but illustrates how targeted technologica l innovation can reduce carbon emissions while maintaining - indee d, growing - energy supply.

[34] Paper presented at GHGT-9 Confer ence and available from the GHGT-9 Conference website cited above.

Response: EPA clarifies that the final Class VI GS rule does not require owners or operators to use GS Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbur y Resources, Inc. (DRI) Comment ID: 24281technologies, nor does it impact business as usual for Class II owners or operators that are injecting CO2 to enhance production of oil or gas. Those owners or opera tors that choose to transition from enhanced recovery to GS may do so, provided they m eet the requirements for Class VI wells.

EPA clarifies that the purpose of the Class VI GS rule is to ensure c onsistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA agrees that GS is one te chnology in a portfolio of options , including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions.

Comment: 5. Clarify jurisdiction across state lines. The proposed rule does not address injection issues across state lines. For example, if the pressure boundary and the CO2 plume traverse across state line s, will the permitte e be required to obtain a UIC permit from the neighboring state? If so, what kind of permit? In addition to requiring monitoring and financ ial assurance, would the neighboring state also set limits on the injection rate s? Etc. Oklahoma DEQ recommends that EPA clarify jurisdiction across state lines.

Response: EPA acknowledges that CO2 plumes may cross state or even international boundaries and encourages cooperation and coordina tion among permitting authorities. Th e final Class VI GS rule, at §146.82(a)(2), requires the owner or operator to identify all State, Tribal, and Territorial boundaries within the AoR. Based on this information, the Director must provide written notification to all States, Tribes, and Territories to inform them of the permit application and ensure that they are involved in any necessary processes; this new requirement was added to the final rule at §146.82(b). The Agency encourages transparency in the permitting process and anticipates that State-State/State-Tribal communication on Class VI permitting will facilitate information shar ing and encourage safe, protective
p rojects.

EPA clarifies that the Class VI permit would be issu ed by the permitting authorit y in the state where the wellhead is located.

Comment: Technical Comments p. 43497, II C: USEPA needs to develop an effective way to handle cross-state boundary issues. Cros s-state boundary issues could be a
p roblem when dealing with pressure fronts in a setting like the Mt. Simon Sandstone, which is present beneath seve ral Midwestern states. In addition, many stationary CO2 sources are loca ted along state boundari es (i.e., power
p lants along major rivers).

Response: EPA acknowledges that CO2 plumes may cross state or even international boundaries and encourages cooperation and coordina tion among permitting authorities. Th e final Class VI GS rule, at §146.82(a)(2), requires the owner or operator to identify all State, Tribal, and Territorial boundaries within the AoR. Based on this information, the Director must provide written notification to all States, Tribes, and Territories to inform them of the permit application and ensure that the y are involved in an y Commenter Name: Saba Tahmassebi Letter ID: 0218 Commenter Or g anization: Oklahoma Department of Environmental Quality (DEQ) Comment ID: 21566

Commenter Name: Edward Mehnert Letter ID: 0221 Commenter Or g anization: Illinois State Geolo g ical Surve y Comment ID: 21636necessary processes; this new requirement was added to the final rule at §146.82(b). The Agency encourages transparency in the permitting process and anticipates that State-State/State-Tribal communication on GS permitting will facilitate information shari ng and encourage safe, protective
p rojects.

Comment: 4. An applicant for CO2 credits must provi de a clear demonstration of longterm CO2 containment. If the CO2 cannot be contained in a geological formation indefinitely, then the operator should not receive a credit.

Response: EPA clarifies that setting a "containment standard " is outside the scope of the Class VI GS rulemaking. However, the Class VI GS rule requires th at CO2 injected for GS remain confined in the injection zone. Leakage outside of the injection zone/to the surface would be a permit violation. The
p urpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United St ates and provide require ments to prevent enda ngerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

EPA clarifies that carbon crediti ng and greenhouse gas accounting are outsi de the scope of the Class VI GS rulemaking. The Class VI GS rule is desi gned to ensure the protection of USDWs from endangerment. However, the Agency acknowledges that these issues are impor tant and is addressing them using other regulatory authorities. For exampl e, in a separate rulemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Ga s Reporting Program at 40 CFR Part 98 to add reporting requirements for CO2 injection and ge ologic sequestration. The greenhouse gas reporting requirements build on the requirements outlined in the Class VI GS rule with the additional goals of verifying the amount of CO2 sequestered and collecti ng data on any CO2 emissions to the surface from Class VI GS facilities.

Comment: Point #7: Multi-state jurisdictional i ssues. Finally, the scale of geologic storage projects could raise multi-state ju risdictional issues if the CO2 plume and AoR extend beyond and across state boundaries. The proposed rule should speak to potential multi-state jurisdicti onal issues in a manner that avoids conflicting state requireme nts. For instance, one option would allow the well head or injection site lo cation to control jurisdiction. This would provide a framework for addressing multi-state jurisd iction and give owners/operators some certainty regarding tbe approach to this issue.

Response: EPA acknowledges that CO2 plumes may cros s jurisdictional boundaries and encourages cooperation and coordination among pe rmitting authorities. The final Class VI GS rule, at §146.82(a) (2), requires the owner or operator to identify al l State, Tribal, and Territ orial boundaries within the AoR. Based on this information, the Director must provide written notif ication to all States, Tribes, and Territories to inform them of the permit applicati on and ensure that they are involved in any necessary
p rocesses; this new requirement was added to the final rule at §146.82(b). The Agency encourages transparency in the permitting process and anticipa tes that State-State/State-Tribal communication on GS permitting will faci litate information sharing and enco urage safe, protective projects. Commenter Name: Jonathon Palm Letter ID: 0222 Commenter Or g anization: Nevada Division of Environm ental Protection, Bureau o f Water Pollution Control Comment ID: 21643

Commenter Name: Darrick Eu g ene Letter ID: 0223 Commenter Or g anization: Texas Carbon Capture and Stora g e Association Comment ID: 23965EPA clarifies that the Class VI permit would be issu ed by the permitting authorit y in the state where the wellhead is located.

Comment: (1) Property Rights Issues Are Matter of State Law

EPA accurately states that the SDWA does not afford EPA the authority to regulate many issues involved in CO2 sequestration, including property rights which are regulated under state law. (73 Fed. Reg. at 43495.) In many instances, the owner of the surface pr operty rights may be different than the owner of the subsurface mineral rights. There may be a legal question as to who owns the subsurface storage rights as between, fo r example, the surface property rights owner and the mineral rights owner. This is a matter of state law as correctly discussed by EPA. BP requests that EPA expand on its assertion in the Preamble that it does not have authority to regulat e in this area and that nothing in the Proposed Rule should be interpreted or infe rred as a grant of subsurface storage rights.

Response: EPA clarifies that pore space ownership and surface and subsurface property and mineral rights are outside of the scope of the Class VI GS rulemaking. These issues are under the purview of states and any of these issues, as they relate to GS, will need to be addressed though st ate regulations.

The UIC program’s authority under SDWA is focu sed on ensuring that where GS technologies are deployed, GS is performed in a manner th at protects USDWs fr om endangerment.

Comment: (3) Proposed Rule Should Not Affect Injection of Oil & Gas Waste

Oil and gas waste (such as produced water and amine waste gases [CO2 and H2S]) are often injected back into the reser voir after separation during oil and gas
p roduction activities. This type of inj ection is and has been historically
p ermissible under Class II regulations. (See 40 CFR § 144.6(b)(1).) EPA was silent on whether the Proposed Rule would in any manner affect the applicability of the Class II well regulat ions for injection of oil and gas waste. EPA should indicate in its Preamble to the Final Rule that the Final Rule does not alter in any manner the applicability of Class II re gulations to injection of oil and gas
waste.

Response: The Agency clarifies that the final Class VI GS rule does not require owners or operators to use GS technologies, nor does it impact business as usual for Class II owners or operators that are injecting CO2 to enhance production of oil or gas. Those owners or ope rators that choose to transition from enhanced recovery to GS ma y do so, provided they meet the requirements for Class VI wells.

Comment: A. Re g ulator y Uncertaint y Commenter Name: Brian Williams Letter ID: 0225 Commenter Or g anization: BP Alternative Ener gy North America, Inc. (BP) Comment ID: 21760

Commenter Name: Brian Williams Letter ID: 0225 Commenter Or g anization: BP Alternative Ener gy North America, Inc. (BP) Comment ID: 21762

Commenter Name: Ben Yama g ata Letter ID: 0227 Commenter Or g anization: Coal Utilization Research Council Comment ID: 21780GS projects need regulatory certainty in order to move forward as a meaningful approach to reduce CO2 emissions. While it is an important first step, the EPA
p roposed rule addresses only one piece of the needed regulatory framework: that is the protection of USDW. CURC understands that the authority delegated to EPA in the SDWA does not perm it the EPA to develop a comprehensive regulatory framework that covers all of the com ponents needed to provide regulatory certainty, which are needed to facilita te the widespread use of GS. This regulatory certainty is e ssential; a number of additional issu es must be addressed by the federal or state govern ments in order for carbon capture and the enabling GS to move forward. Chief among these issues are:

1. the surface property rights associated with GS wells; 2. subsurface and pore space rights associated with GS wells; 3. flexibility in the ruling that allows tr ansfer of geologic storage (GS) sites and CO2 ownership, monitoring and mitigation responsibility from one entity to another; and 4. long-term liability.

Response: EPA clarifies that pore space ownership and surface and subsurface property and mineral rights are outside of the scope of th e Class VI GS rulemaking. The purpose of the Class VI GS rule is to ensure consistency in permitting underground injecti on of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA recognizes the im portance of providing clea r, flexible, scalable, and appropriate regulations. EPA believes that the GS regulation will provide certainty to industry and the public by providing cons istency in requirements across the U.S. and transparency about what requirements apply to owners or operators.

Regarding transfer of GS sites, the Agency acknowle dges that owners or opera tors of wells regulated under existing well classifications ma y seek to re-permit th eir wells for GS. Howeve r, the Class VI GS rule does not allow for automatic transfer of a Cla ss VI permit to a new owner or operator; see §144.38 (b). Given the unique nature of GS and the importa nce of interaction betwee n GS project owners or operators and permitting authorities, the Agency believ es that the Director should have an opportunity to review the permit and determine whether any changes are necessary at the time of the permit transfer,
p ursuant to requirements at §146.38(a). If informat ion about the GS project and existing permit conditions are determined to be adequate, the permit review and transfer may entail a minimal amount of new information and administrative effort.

Regarding long-term liability, once an owner or ope rator has met all requirements under Part 146 for Class VI wells and the Director has approved site closure pursuant to requirements at §146.93, the owner or operator will ge nerally no longer be subject to enfo rcement for regulat ory noncompliance. Furthermore, their financial inst rument as required under §146.85 will be released if it was not used. However, even if a site closure is approved under §146.93, an owner or operator ma y be held liable for regulatory noncompliance (including violation of 40 CFR 144.12) in certain circumstances. For example, an owner or operator may be held liable for regulatory noncompliance even after site closure was approved if the Director relied on erroneous information (e.g., erroneous modeling data) provided by the owner or operator when approving site closure.

Separate from EPA’s authorit y to enforce regulatory compliance, an owner or operator may be subject to a §1431 response order even after proper site closure is approved under §146.93. Under §1431 the Administrator may require an owner or operator to take necessary response measures if he or shereceives information that a contaminant is present or is likely to enter a public water system or an USDW, which may present an imminent and substantia l endangerment to the heal th of persons, and the appropriate State and local authorities have not acted to protect the health of such persons. The action may include issuing administrative orders or commencing a civil action for appropriate relief against the owner or operator of a Class VI well. If the owner or operator fails to comply with the order, they may be subject to a civil penalty for each day in which such violation occurs or failure to comply continues.

Furthermore, after site closure an owner or operator may remain liable under tort and other remedies, or under other federal statutes including, but not li mited to, Clean Air Act, 42 U.S.C. §§ 7401-7671; CERCLA, 42 U.S.C. § 9601-9675; and RCRA, 42 U.S. C. § 6901-6992. EPA does not have authority to transfer SDWA or other legal liabil ity for Class VI wells to the Stat e or federal government or a thirdp arty fund. See the final rule preamble for further discussion of EPA's final approach to financial responsibility for Class VI wells.

Comment: Page 138, Primacy/Jurisdicti on- Given the size and location of potential GS
p rojects, many storage areas are likely to cross state lines. For example almost all of the major sources of CO2 em issions in the MRCSP region are at or near state boundaries, along Ohio River. For example, a geologic storage facility located near Wheeling West Vi rginia could have a CO2 plume and injection well locations in Ohio, West Virginia, and Pennsylvania. It is unclear how these projects would be impl emented regarding who has primacy in
p ermitting the site under a si ngle permit, rather than three separate permits. Additional guidance permitting sites with multiple jurisdictions is highly desirable to prevent confusion or legal challenges.

Response: EPA acknowledges that CO2 plumes may cros s jurisdictional boundaries and encourages cooperation and coordination among pe rmitting authorities. The final Class VI GS rule, at §146.82(a) (2), requires the owner or operator to identify al l State, Tribal, and Territ orial boundaries within the AoR. Based on this information, the Director must provide written notif ication to all States, Tribes, and Territories to inform them of the permit applicati on and ensure that they are involved in any necessary
p rocesses; this new requirement was added to the final rule at §146.82(b). The Agency encourages transparency in the permitting process and anticipa tes that State-State/State-Tribal communication on Class VI permitting will facilita te information sharing and encour age safe, protective projects.

Other EPA Comment Codes and Descriptions: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 Comment: 7. EPA’s laudable efforts not withstanding, we believe th e Safe Drinking Water Act (SDWA) does not provide adequate authority to comprehensively regulate GS. Because the statutory authority for the UI C Program derives from the SDWA, the
p roposed rule is unable to address key issues that must be resolved for commercial-scale GS,[FN1] such as:

• ownership of pore space (discussed in Chapter 5 of attached report); • potential human health or ecolo g ical impacts if carbon dioxide leaks to the Commenter Name: Neera j Gupt a Letter ID: 0229 Commenter Or g anization: Battelle Ener gy Technolo gy (BET) Comment ID: 21867

Commenter Name: M. Gran g er Mor g an Letter ID: 0233 Commenter Or g anization: Carnegie Mellon University on behalf of the CCS Reg Pro j ect Comment ID: 21899surface or nea r -surface (discussed in Chapters 1, 4, and 6 of attached report); • long-term liability (discussed in Chap ters 7 and 8 of atta ched report); and, • greenhouse gas regulatory accounting, which will be the enabling link to incentive structures that make GS economically viable (discussed in Chapters 8 and 9 of attached report).

[FN1: These limitations ar e acknowledged by the agency in the preamble to the rule. (73 FR 43,495)]

8. Failure to resolve the above issues coul d make the commercial development of CCS impossible.

Response: EPA acknowledges that GS falls within the broader context of CCS and the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordina ted with other Agency program of fices and across federal agencies (e.g., with the Department of Energy; United St ates Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Minerals Management Service; and the Bureau of Land Management). The Agen cy continues to evaluate areas of potential applicability of other Federal environmental statutes including, but not limited to: the Clean Air Act; the Resource Conservation and Recovery Act; the Comprehens ive Environmental Res ponse, Compensation, and Liability Act; and the Marine Prot ection, Research and Sanctuaries Ac t to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize redundancy and maximize efficiencies for owners or operators . For additional information, please see the discussion entitled "How Does This Rulemaking Relate to Othe r Federal Authorities and GS and CCS Activities?" in the preamble to th e final GS rule.

EPA is also aware that states are currently in various stages of devel oping statutory frameworks, regulations, technica l guidance, and strategies for addressi ng CCS and GS. States can use multiple authorities beyond those afforded under the SDWA and UIC regulations, including laws and policies addressing surface access and land ri ghts, unitization of fields, pore space ownership, mineral rights, worker safety and emergency prepar edness, and maximization of state oil and gas resource exploitation. EPA plans to work closely with states and tribes as they develop Class VI primacy programs in this broader context. EPA adds that st ates may adopt more stringent stan dards for Class VI wells than the Federal requirements.

The final rulemaking falls within EPA’s authorit y under the SDWA. EPA clarifies that the SDWA
p rovides EPA with the authority to develop federal minimum requirements for underground injection, such as GS, that are directly related to protecti ng USDWs from endangerment. Thus EPA does not have authority under the SDWA to address other genera l issues related to CCS, such as capture and transportation. EPA clarifies that th e GS rule does not address the status of CO2 as a pollutant or commodity. The UIC requirements regul ate the injection of fluids. EP A adds that regulating carbon capand trade is outside of the UIC program's authority under SDWA.

EPA recognizes that liability is an important issue to owners or opera tors but the Agency does not have authority under the SDWA to transfer long-term liability from owners or operators to the state or federal government. Therefore, liability remains with the owner or operator.

Commenter Name: M. Gran g er Mor g an Letter ID: 0233 Commenter Or g anization: Carnegie Mellon University on behalf of the CCS Reg Pro j ect Comment ID: 21901Other EPA Comment Codes and Descriptions: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 Comment: Overarching recommendations

10. The inability of the proposed rule to manage the issues listed above should be remedied by either:

a. passage of new federal legislation to supplement the UIC program and amend the SDWA; or b. passage of new freestanding fede ral legislation to regulate GS comprehensively. These options are detailed in Chapter 6 of the attached report [SEE PDF TO VIEW THE REPORT].

Response: This comment is outside the scope of this rulemaking. As described above, EPA recognizes that a more comprehensive framework may be needed and that some stakeholders remain uncertain about the potential applicability of other federal environmental statutes , such as the Clean Air Act, to various aspects of GS. The Agency is currently evaluating the need for a more comprehensive regulatory framework for this emerging technology.

Other EPA Comment Codes and Descriptions: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 Comment: Issues that would require ment amendment of the SW DA or passage of new legislation

13. Need to balance multiple environmen tal interests: Protection of drinking water is an essential environmental goal, but must be balanced with avoidance of the dangerous impacts of climate change. As mandated by the SDWA, the UIC Program rules have been developed with the objective of preventing any migration of injected fluid or other contaminants into USDWs. In practice, however, regulatory treatment of inj ectate migration has been le ss clear-cut. For example the experience in Florida, discussed in Chapter 6 of the attached report [SEE PDF TO VIEW THE REPORT], suggests that it would be highly desirable to have ar rangements in place ahead of time to allow balancing of potentia lly conflicting national environmental interests. We recommend that the SDWA be amended to allow balancing multiple environmental interests.

Response: This comment is outside the scope of the rulemaking. As described above, EPA recognizes that a more comprehensive framework may be needed and that some stakeholders remain uncertain about the potential applicability of other federal environmental statutes , such as the Clean Air Act, to various aspects of GS. The Agency is currently evaluating the need for a more comprehensive regulatory framework for this emerging technology. Commenter Name: M. Gran g er Mor g an Letter ID: 0233 Commenter Or g anization: Carnegie Mellon University on behalf of the CCS Reg Pro j ect Comment ID: 21904

Commenter Name: M. Gran g er Mor g an Letter ID: 0233 Commenter Or g anization: Carnegie Mellon University on behalf of the CCS Reg Pro j ect Comment ID: 21905Comment: 14. Ownership of Pore Space: Considerable ambiguity exists today in the U.S. as to the current ownership of the deep pore space that would hold injected CO2, and how the right to use deep pore space would be obtained for GS purposes. It appears that most injectors of waste fluids into other well classes regulated by the UIC have not s ecured rights or permission to use the pore space from any surface or sub-surface property owners. At least a few of those injection
p rojects likely involve volumes of fluid as large or larger than the volumes of CO2 that will be involved in commercial-s cale CCS projects. In order for CCS to remain an economic possibility, new legisl ation must allow the federal or state governments to intervene to manage or li mit private property rights for the use of pore space for GS. Otherwise, states or private property ow ners could demand high rental rates that could block development of CCS.

Response: EPA clarifies that pore space ownership and surface and subsurface property and mineral rights are outside of the scope of the Class VI GS rulemaking, which fo cuses on ensuring consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provides requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA clarifies that these issues are unde r the purview of states and any of these issues, as they relate to GS, will need to be addressed though state regulations.

Comment: Beyond establishing regulations to govern the actual process for managing the injection of CO2 into underground formati ons, there are other important matters that must also be addressed before ca rbon capture and geologic storage (CCGS) operations can be developed. These matter s are clearly beyond the scope of the regulations proposed by EPA. Included are:

1. The creation of a legal framework for a storage facility operator to obtain control of the reservoir and associated pore space to be used for C02 storage. The right to use reservoirs and associ ated pore space is a private property right that must be acquired from the ow ner of the property. Included with this framework must be a method for amalgamati ng or consolidating the rights in order to provide for the orderly development of a long-term storage project. Given that these actions pertain to the acqui sition or control of private property rights, they are functions to be established by state law.

Response: EPA clarifies that pore space ownership and surface and subsurface property and mineral rights are outside of the scope of the Class VI GS rulemaking, which fo cuses on ensuring consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA clarifies that these issues are unde r the purview of states and any of these issues, as they relate to GS, will need to be addressed though state regulations.

Comment: 3) Landowners: Land ownership may change th rough the course of a CCS facility’s life. At some sites, the surface owner of a plot of land will not own the pore space underneath. W y omin g is the onl y state we are aware of that has clarified Commenter Name: Robert E. Carter Jr. Letter ID: 0236 Commenter Or g anization: Indiana Department of Natural Resources (IDNR) Comment ID: 23201

Commenter Name: Rand y Joseph Letter ID: 0240 Commenter Or g anization: Western Organization of Resource Councils Comment ID: 23221ownership rules, and clearly states that the surface owner owns the pore space for carbon storage, but Wyoming law allo ws ownership of the surface and pore space to be severed. Thus, it is likely that multiple prope rty rights will be involved in any geologic sequestration site, particularly where geologic sequestration is proposed at sites where oil, gas and coal are already being developed.

One of the aspects of having split esta tes is that the surface owner, who suffers most if a site is not appropriat ely closed and reclaimed, may not be the
p arty who is doing the actual closure and reclamation work. In our experience, surface owners often have little ability to ensure that appropriate siting, operating, monitoring, closure and reclamat ion controls are in place. These landowners must rely on the regulatory agency to protect their interests.

Response: EPA clarifies that pore space ownership and surface and subsurface property and mineral rights are outside of the scope of the Class VI GS rulemaking, which fo cuses on ensuring consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provides requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA clarifies that these issues are unde r the purview of states and any of these issues, as they relate to GS, will need to be addressed though state regulations.

Other EPA Comment Codes and Descriptions: 1200 1.1 General comments about the rulemaking Comment: WEST Associates Comments on the Proposed Rule

The following are WEST's comments on the Preamble and proposed rule, which we believe will clarify and strengthen the proposal:

–Under the proposed UIC regulation, siting UIC wells for GS in the west will likely involve a challenging set of nationa l agencies, states, and tribal sets of regional and sub-regional regulation that will require streamlining in order to site UIC wells and pipe lines to transfer super critical CO2 to GS sites located at some distances away from coal fired power plants. Such projects will cross over many jurisdictions and i nvolve a patchwork of regulatory requirements. This will require coordination among federal and tribal j urisdictions since it is hi ghly likely that most west ern projects will impact federal lands, including tribal lands. EP A should immediately start working towards building support and consensus am ong the federal land managers and BIA for the UIC regul atory program.

Response: EPA understands that the CO2 plumes for la rge GS projects may cross State, Tribal, Territorial, EPA Regional, or national boundaries. The final GS rule, at §146.82(a)(2), requires the owner or operator to identify all State, Tribal, and Territorial boundaries within the AoR. Based on this information, the Director mu st provide written notification to all St ates, Tribes, and Territories to inform them of the permit application §146.82(b) and ensure that they are involved in any necessary processes (e.g., development of the emergency and remedial response plan (§146.94)). The Agency encourages transparency in the permitting process and anticipa tes that State-State/State-Tribal communication on GS permitting will faci litate information sharing and enco urage safe, protective projects. Commenter Name: Kevin Wantta j a Letter ID: 0248 Commenter Or g anization: Western Ener gy Suppl y and Transmission Associates Comment ID: 22240EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

Comment: ROUNDTABLE CONCERNS

As policymakers and project developers work through the many nuances involved with large-scale CCS, we believe that it is important to keep focused on this central tenet: strong and early inve stment in CCS technologies and infrastructure is a necessary foundation for any viable cl imate change regulatory regime.

Response: EPA clarifies that the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA agrees that GS is one te chnology in a portfolio of options , including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the intent of the Class VI GS regulat ions is not to promote or incentivize the use of GS, but, instead to ensu re protection of USDWs wh ere GS technologies are deployed.

EPA recognizes the importance of providing clear, fl exible, scalable, and appropriate regulations. EPA believes that the Class VI GS regulation will pr ovide certainty to industr y and the public by providing consistency in requirements across the U.S. and tran sparency about what requirements apply to owners or operators.

Other EPA Comment Codes and Descriptions: 1420 1.2.1.1 Support the GS rulemaking Comment: It is also essential that the U.S. Envi ronmental Protection Agency (EPA) take supplemental action, based on other (non-SD WA) authority, to provide additional assurance that injected CO2 will not be released into the atmosphere in a way that adversely impacts the climate or otherwise endangers public health and welfare. Generally, the steps needed to pr otect USDWs are also needed in order to prevent emissions to the atmosphere. Supplemental steps citing additional authority should also guarantee that CO2 in jected into geologic formations stays out of the atmosphere. This should be done accordin g to a permanence Commenter Name: James T. Sims Letter ID: 0249 Commenter Or g anization: Western Business Roundtable Comment ID: 22257

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22271(performance) standard, which will ce rtify CO2 as ‘geol ogically sequestere d ’ for that purpose, in addition to protecting US DWs. These are needed, as none of the existing or proposed injection classes are adequate for the task of certifying CO2 as permanently sequestered for th e purposes of preventing atmospheric releases. In order to be fully protective of the environment, Congress will also need to pass comprehensive cap and trade legislation to control the emission of greenhouse gases from all anthropogenic sources. But the need for such legislation is not a basis for deferring the adoption of EPA rules to protect USDWs or to assure that injected CO2 does not result in harmful releases to the atmosphere.

Response: EPA acknowledges that the issue of GS falls within the broader context of CCS, but clarifies that the scope of the GS regulation is limited to in jection of CO2, and that al l requirements in the GS rule are designed for the purpose of protecting USDWs from endangerment. The SDWA does not
p rovide the UIC Program with the authority to devel op regulations for all areas related to GS, such as releases to the atmosphere. "Cap and trade" legislat ion is outside of the scope of this rulemaking. The UIC requirements are designed to ensure that, where GS is employed, it is done in a manner that protects USDWs from endangerment.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

In a separate rulemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Gas (GHG) Reporting Program at 40 CFR Part 98 to add re porting requirements for facilities that conduct GS (subpart RR) and all other facilities that inject CO2 underground (subpart UU). For additional information, see the s ection of the final GS rule preamble enti tled, "How Does Mandatory Reporting of Greenhouse Gases (GHGs) Relate to This Rulema king?” and the GHG Repor ting Program rulemaking and docket.

Other EPA Comment Codes and Descriptions: 1290 1.1.2.2 Comments that EPA should regulate CO2 as a pollutant Comment: The Supreme Court recognized in Massac husetts v. EPA [FN2] that EPA has authority and, indeed an obligation, under the Clean Air Act to regulate emissions of greenhouse gases, including CO 2, that "cause or contribute to air
p ollution that may reasonably be anticipated to endanger public health or welfare." [FN3] Similarly, the D.C. Circ uit’s remand of the power plant new source performance standards ("NSPS") places EPA in the position to re g ulate CO2 Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22272emissions from new and also existing s ources within that industrial sector. [FN4] The Environmental Appeals Board EAB also recently has rejected the agency’s arguments that it is not authorized to issu e best available control technology (BACT) emissions limits for CO 2 in the context of a new source air
p ermit decision for a large new coal-fired power plant, under the Clean Air Act’s Prevention of Significant Deterioration (PSD) new source review authority. [FN5]

[FN2: 127 S.Ct. 1438 (2007).] [FN3: Id. at 1460-61.] [FN4: Order, NY, et al. v. EPA, D.C. Cir. No. 06-1322 (Sept. 24, 2007). Once N SPS are set for an industry under sect ion 111(b), 42 U.S.C. §7411(b), the Act requires EPA to set standards for states to regulate emissions from existing sources in that industry. 42 U.S.C. § 7411(d).] [FN5: In re: Deseret Power Electric Coop., PSD App. No 07-03, Slip Op. (Nov. 13, 2008). The memorandum issued December 18, 2008 by Administrator Johnson entitled "EPA’ Interpretation of Regulations that determine Pollutants Covered by Federal Prevention of Significant Deterioration (PSD) Permit Program" (Johnson PSD memo) is procedurally deficient, and, in any even t, states explicitly on its face that it is not intended to supersede the EAB’s decision in the Deseret case. Johnson memo at 2. Nor, indeed, can it lawfully do so.]

Response: The purpose of the Class VI GS regulation is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. The requirements apply only to GS injection technologies includi ng well construction, operation, monitoring and testing technologies. The Supreme Court decision under Massachusetts v. EPA and Clean Air Act (CAA) provisions related to New Source Performance Stan dards (NSPS) and Best Available Control Technology (BACT) determinations are outside the scope of this Class VI GS rulemaking.

The Class VI GS rulemaking is promulgated under Safe Drinking Wa ter Act authority and does not relate to any endangerment and cause or contribute findings under the Clean Air Act. The Class VI GS requirements do not depend upon, and are unaffected by, Clean Air Act endangerment and cause or contribute findings. More information on EPA's E ndangerment and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act can be found at http://www.epa.gov/climatech ange/endangerment.html.

In a separate rulemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Gas Reporting Program at 40 CFR Part 98 to add repor ting requirements for CO2 injection and geologic sequestration. The greenhouse gas reporting requireme nts build on the requirements outlined in the Class VI GS rule with the additional goals of ve rifying the amount of CO2 sequestered and collecting data on any CO2 emissions to the surface from GS facilities.

Comment: As EPA correctly notes in the preamble of this rule, several key areas remain to be addressed that are beyond the EPA's authority under the SDWA before commercial scale carbon capture and storage will occur. Examples of these areas indude mana g ement of lon g lerm responsibiht y for stora g e sites, monetization of Commenter Name: Ken Mille r Letter ID: 0257 Commenter Or g anization: ExxonMobil Production Compan y Comment ID: 22370CO2 in a way that does not adversely aff ect economic development and prospenty,
p ublic education and awareness, and devel opment of balanced property rights and access principles.

Response: EPA clarifies that the purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. Establishing a price for carbon and property rights issues are outside of the scope of the GS rule.

EPA recognizes the importance of providing clear, fl exible, scalable, and appropriate regulations. EPA b elieves that the GS regulation will provide certainty to industry and the public by providing consistency in requirements across the U.S. and transparency about what requirement s apply to owners or operators.

EPA notes that long-term liability is outside of the scope of the GS rulemaking and is not addressed in the GS rule. SDWA does not contain any express provisions addressing liability. An owner or operator will be held liable for any pe rmit violations under SDWA §1423.

Under the final GS rule, once an owner or operato r has met all regulatory requirements under Part 146 for Class VI wells and the Direct or has approved site closure pur suant to requirements at §146.93, the owner or operator will ge nerally no longer be subject to enfo rcement for regulat ory noncompliance. Furthermore, their financial inst rument as required under §146.85 will be released if it was not used. However, even if a site closure is approved under §146.93, an owner or operator ma y be held liable for regulatory noncompliance (including violation of 40 CFR 144.12) in certain circumstances. For example, an owner or operator may be held liable for regulatory noncompliance even after site closure was approved if the Director relied on erroneous information (e.g., erroneous modeling data) provided by the owner or operator when approving site closure.

Separate from EPA’s authorit y to enforce regulatory compliance, an owner or operator may be subject to a §1431 response order even after proper site closure is approved under §146.93. Under §1431 the Administrator may require an owner or operator to take necessary response measures if he or she receives information that a contaminant is present or is likely to enter a public water system or an USDW, which may present an imminent and substantia l endangerment to the heal th of persons, and the appropriate State and local authorities have not acted to protect the health of such persons. The action may include issuing administrative orders or commencing a civil action for appropriate relief against the owner or operator of a Class VI well. If the owner or operator fails to comply with the order, they may be subject to a civil penalty for each day in which such violation occurs or failure to comply continues.

Furthermore, after site closure an owner or operator may remain liable under tort and other remedies, or under other federal statutes including, but not li mited to, Clean Air Act, 42 U.S.C. §§ 7401-7671; CERCLA, 42 U.S.C. § 9601-9675; and RCRA, 42 U.S. C. § 6901-6992. EPA does not have authority to transfer SDWA or other legal liabil ity for Class VI wells to the Stat e or federal government or a thirdp arty fund. See the final rule preamble for further discussion of EPA's final approach to financial responsibility for Class VI wells.

Comment: Finally, although NACCSA recognizes the limits on the Agency's jurisdiction with regard to CCS projects, its members a ppreciate the Agency raising for public comment issues related to propert y ri g hts that ma y be associated with CO2 in j ection and stora g e, such as Commenter Name: Michael Moore Letter ID: 0265 Commenter Or g anization: North American Carbon Capture & Storage Association (NACCSA) Comment ID: 22874ownership of pore space in which CO2 will be stored, as well as issues of long-term responsibility for stored CO2 and storage site integrity. While the importance of EPA's rulemaking as an important step in providing clarity and certainty for project operators and investors cannot be oversta ted, CCS projects may not go forward in the absence of resolution of these issues. EPA's effort s in this regard will serve to raise stakeholder and policy maker awareness rega rding the importance of resolving these critical issues so necessary to the su ccessful commercial de ployment of CCS.

Response: EPA acknowledges the comment. EPA agrees that pore space ownership issues are outside the scope of the Class VI GS rulemaking; these are under the purview of states and any of these issues, as they relate to GS, will need to be addressed though state regulations. The purpose of the Class VI GS rule is to ensure consistency in permitting underg round injection of CO2 at GS operations across the United States and provide require ments to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

EPA recognizes the importance of providing clear, fl exible, scalable, and appropriate regulations. EPA believes that the Class VI GS regulation will pr ovide certainty to industr y and the public by providing consistency in requirements across the U.S. and tran sparency about what requirements apply to owners or operators.

EPA notes that long-term liability is outside of the scope of the GS rulemaking and is not addressed in the GS rule. SDWA does not contain any express provisions addressing liability. An owner or operator will be held liable for any pe rmit violations under SDWA §1423.

Under the final GS rule, once an owner or operato r has met all regulatory requirements under Part 146 for Class VI wells and the Direct or has approved site closure pur suant to requirements at §146.93, the owner or operator will ge nerally no longer be subject to enfo rcement for regulat ory noncompliance. Furthermore, their financial inst rument as required under §146.85 will be released if it was not used. However, even if a site closure is approved under §146.93, an owner or operator ma y be held liable for regulatory noncompliance (including violation of 40 CFR 144.12) in certain circumstances. For example, an owner or operator may be held liable for regulatory noncompliance even after site closure was approved if the Director relied on erroneous information (e.g., erroneous modeling data) provided by the owner or operator when approving site closure.

Separate from EPA’s authorit y to enforce regulatory compliance, an owner or operator may be subject to a §1431 response order even after proper site closure is approved under §146.93. Under §1431 the Administrator may require an owner or operator to take necessary response measures if he or she receives information that a contaminant is present or is likely to enter a public water system or an USDW, which may present an imminent and substantia l endangerment to the heal th of persons, and the appropriate State and local authorities have not acted to protect the health of such persons. The action may include issuing administrative orders or commencing a civil action for appropriate relief against the owner or operator of a Class VI well. If the owner or operator fails to comply with the order, they may be subject to a civil penalty for each day in which such violation occurs or failure to comply continues.

Furthermore, after site closure an owner or operator may remain liable under tort and other remedies, or under other federal statutes including, but not li mited to, Clean Air Act, 42 U.S.C. §§ 7401-7671; CERCLA, 42 U.S.C. § 9601-9675; and RCRA, 42 U.S. C. § 6901-6992. EPA does not have authority to transfer SDWA or other legal liabil ity for Class VI wells to the Stat e or federal government or a thirdp arty fund. See the final rule preamble for further discussion of EPA's final approach to financial responsibility for Class VI wells.Other EPA Comment Codes and Descriptions: 5400 2.9 Proposed Financial Responsibility and Long-Term Care Requirements Comment: drinking water, particularly sole-source aquifers. Other concerns include unproven technology to be used for inje ction wells, undefined water rights between states sharing a single undergr ound source of water, and unresolved long-term liability and financial respon sibility for sequestration sites. We

Response: EPA clarifies that subsurface property rights, including water right s, are outside the scope of the GS rulemaking.

Under SDWA authority, owners or op erators of injection wells must ensure protection of USDWs from endangerment and are subject to liab ility for enforcement under the Act. The final rule requires that an owner or operator must conduct moni toring as specified in the Direct or-approved PISC and site closure
p lan following the cessation of inject ion until the owner or operator can demonstrate to the Director that the geologic sequestration proj ect no longer poses an endangerm ent to USDWs. For additional information about the PISC and si te closure requirements, see the preamble to the final GS rule.

Once an owner or operator has met all regulatory requirements under Part 146 for Class VI wells and the Director has approved site clos ure pursuant to requirements at §146.93, the owner or operator will generally no longer be subject to enforcement fo r regulatory noncompliance. Furthermore, their financial instrument as required unde r §146.85 will be releas ed if it was not used. However, even if a site closure is approved under §146.93, an owner or operator may be held liable for regulatory noncompliance (including violation of 40 CFR 144.12) in certain circum stances. For example, an owner or operator may be held liable for regulatory noncompl iance even after site cl osure was approved if the Director relied on erroneous information (e.g., er roneous modeling data) provided by the owner or operator when approving site closure.

Additionally, an owner or operato r may always be subject to a ny action the Administrator deems necessary to protect the health of persons under §1431 of the SDWA after site closure if there is unanticipated migration towards or into a USDW th at causes or threatens imminent and substantial endangerment to public health. The action may include issuing administrative orders or commencing a civil action for appropriate relief. If the owner or ope rator fails to comply with the order, they may be subject to a civil penalty for each day in which such violation occurs or failure to comply continues.

The Agency clarifies that Class VI well permits may be transferred to another owner or operator
p ursuant to §144.38 whereby generally al l other regulatory responsibilitie s are transferred to that new owner and operator, which includes al l potential liabilities associated with meeting the requirements of that permit. Please see furt her clarification on the issue of long term liability in the pr eamble of the final rule.

Furthermore, after site closure an owner or operator may remain liable under tort and other remedies, or under other federal statutes including, but not li mited to, Clean Air Act, 42 U.S.C. §§ 7401-7671; CERCLA, 42 U.S.C. § 9601-9675; and RCRA, 42 U.S. C. § 6901-6992. EPA does not have authority to transfer SDWA or other legal liabil ity for Class VI wells to the Stat e or federal government or a thirdp arty fund. See the final rule preamble for further discussion of EPA's final approach. Commenter Name: Mic Stewart Letter ID: 0279 Commenter Or g anization: Metropolitan Water District of Southern California Comment ID: 24094Other EPA Comment Codes and Descriptions: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 Comment: Third, we raise the issue of authority. The rulemaking to date has only cited authority under the Safe Drinking Water Act (S DWA). As we stated in our comments of Dec24, 2008, an appropriate regulatory regime for GS must also be grounded on authority to prevent re-emissions of inj ected carbon dioxide to the atmosphere. The proposed rule defines GS solely for the purposes of protecting Underground Sources of Drinking Water (USDWs). Climate legislation is presently being drafted in Congress however, and will very likely rely on EPA’s injection classes to certify GS. Specifically, the legislation wi ll very likely exempt carbon dioxide emissions from la rge facilities th at are geologically sequestered according to regulations promulgated by EPA and/or other agencies. We stress the importance of EPA being ready and prepared to meet such requirements. Accounting
p rotocols for carbon allowances is an issu e that can be dealt with outside the scope of the current rulemaking, and is like ly to have a far narrower remit than the current rule’s specific requirement s for site screening, monitoring, and various plans. EPA, therefore, must defi ne and regulate GS from the outset in a way that assures not only that USDWs are not endangered, but that GS for the
p urposes of climate protecti on is also taking place.

Response: EPA clarifies that the scope of the GS regulation is limited to injection of CO2, and that all requirements in the GS rule ar e designed for the purpose of protecting USDWs from endangerment. Consequently, this comment is outside the scope of the rulemaking. The SDWA does not provide the UIC Program with the authority to de velop regulations for all areas relate d to GS, such as releases to the atmosphere.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

To protect USDWs from endangerment and meet the potentially fast pace of GS deployment, EPA is using an adaptive approach to re gulating CO2 injection for GS. The Ag ency plans to collect and review data every six years on GS projects to determin e whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or nece ssary. An adaptive approach will allow regulatory development to
p roceed in time to meet the current and future demands for Class VI permit s while EPA continues to gather data from pilot projects and othe r research as it becomes available. Commenter Name: Geor g e Peridas Letter ID: 0291 Commenter Or g anization: Natural Resources Defense Council Comment ID: 25287Comment: In my opinion, the best way to resolve is to attack it from a broad standpoint of changing the way you burn it , changing the way you do that type of process. I don't know how far they've got ten in the past five years, technology has changed so drastically in likely the way we attack different problems, with chemicals, with types of things that they can in ject into the carbon to get different results, where you could actually isolat e the carbon dioxide molecule, that kind of thing. But people have been working on that.

Anyway, I'd like to see a little more m oney and focus put towards that rather than putting this crap in the ground. It's ju st, to me it's a bad idea, and it's not really a problem, and it gets us by for a while, sure. But in the long run our kids are going to pay for it. Thank you.

Response: EPA clarifies that the UIC program’s au thority under SDWA is focused on ensuring
p rotection of USDWs from endangerment. The capture of CO2 is outside of the scope of the Class VI GS rulemaking.

EPA does not believe that a properl y managed GS site is dangerous. The Class VI GS regulation builds upon the long-standing protective framework of the UIC program, which has been regulating the injection of billions of ga llons of liquids for decades. The Class VI GS regulation enhances this existing framework with requirements for Class VI wells that are tailored to th e unique nature of large scale GS of CO2. These additional protective requirements in clude more extensive geologic testing, detailed computational modeling of the AoR and periodic re-evaluations, deta iled requirements for monitoring and tracking the CO2 plume and pressure front, and extended post-injection moni toring and site care.

Comment: MR. KALLIO: My name is Brad Kallio. I ha ve a little research company in Grand Rapids, Michigan. We try our best to so lve different types of problems with energy and what have you.

And the easiest way to say it would be , wind generation is something that's going be used for years and years and years. -- uses the old, big windmill. They don't move real fast, they don't chop a lo t up, we don't have birds hitting them and getting cut in half, which they do ha ve in -- they're moving very slow.

But what we do with wind, especially in these areas here, is that when you got a whole amount of wind, has anybody ever w ound a cuckoo clock, pull the little chains up and the weight goes up, and it keeps the little pendulum going? Same
p rinciple, only instead of lifting a littl e metal weight you're lifting, like what he wants to d o, his whole house.

But any mass is a lot of we ight if you lift it up. And as soon as it gets to a certain height it clicks over to anothe r gear system. And then the wind keeps blowing, picks up another one, and anothe r one, and another one. You can do a whole sequence of these along the s horeline or anything like that.

N ow, y ou're not storin g y our ener gy in batteries, y ou're storin g y our ener gy in Commenter Name: Brad Kallio Letter ID: 0502 Comment ID: 21232

Commenter Name: Brad Kallio Letter ID: 0502 Comment ID: 21233gravity. And when you don't have wind you can also use solar to generate motors to do the same thing. It's just like a windmill kind of thi nking, you pull it up and you store it. It goes into a fly wheel at the other end, with a generator on the other end of it now you've get a turb ine generator just like you have in a coal mining plant with no emissions . You can build these anywhere.

And this is only one way of doing it . There's dozens of other ways, any difference in potential from one to the ot her you can harness and turn it into, drive into a system like that, a nd now you're not polluting at all.

So I believe in keeping it simple, the Romans did this kind of stuff that moves water from one point to another, it's old technology but we can apply it to what we have today. I mean, that's more effici ent than ever having to burn coal or oil or any of this stuff. That's what I had to say.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in these technologies is outside the scope of the Class VI GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, proj ects are permitted, sited, constructed, operated, and closed in a manner that protec ts USDWs from endangerment.

Comment: Now, there are some, a couple other things . While the EPA is very careful about saying that this does not cover Clean Air Act there are other things that they should admit that it does not cover. The EPA's permitting process cannot affect landowners' property rights. And the proposed rule should point this out explicitly.

For example, there's an ADM sequestrat ion test in the middle of Decatur, Illinois, it's in a sandstone formation. Bu t if that were in limestone it would undermine the City of Decatur I think they'd be pretty upset that it was asserted that the EPA permit prevente d them from recovering against ADM.

Response: EPA clarifies that pore space ownership and surface and subsurface property and mineral rights are outside of the scope of the Class VI GS rulemaking; these are under the purview of states and any of these issues, as they relate to GS, will need to be addressed though state regulations. The Class VI GS requirements are designed to ensure that, where GS is deployed, projects are permitted, sited, constructed, operated, and closed in a manner that protects USDWs from endangerment.

In a separate rulemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Gas Reporting Program at 40 CFR Part 98 to add repor ting requirements for CO2 injection and geologic sequestration. The greenhouse gas reporting requireme nts build on the requirements outlined in the Class VI GS rule with the additional goals of ve rifying the amount of CO2 sequestered and collecting data on any CO2 emissions to the surface from GS facilities. Commenter Name: Mark Sin g e r Letter ID: 0504 Commenter Or g anization: Green America Pro j ect, LLC Comment ID: 21250

Commenter Name: Leslie Glustrome Letter ID: 0527 Comment ID: 21410Comment: Lastly, another thing I would like to remi nd EPA and all of the participants is that Tom Friedman and his recent focus poi nt book has pointed out that Americans are learning that we can no longer be "as dumb as we want to be" and that nothing will happen. We have seen what ha s happened on Wall Street. We have seen what happened in Iraq that was unjusti fied. Right now, we are flying on the assumption that we have two hundred years to rely on coal energy in this country. Anybody who says that has not read the U.S.G.S (United States Geological rvey) reports on coal availability. That shoul d be, in my mind, part of the preamble to this so that we, as a country, can come to face the fact that we actually only have a very small percenta ge of that "200 years." A most recent study tells us about 6%. Six percent of 200 is about 12 years depends upon how we look at the Powder River field up in Wyoming. So the r eality is very different than what we have been told in the media. As Americans we like to think this is not unusual actually. We have been told lots of things that were not exactly true, so it is time to sit up, pay attention and demand answers, not demonstrate what we want them to be.

N ext I would like to point out that li fe does not follow models. You can do anything on a computer. You can make assumptions about anything and when you look at the models that have been used, Mi ke Celia models or whoever you want to use, they make assumptions that basically determine the outcome. In the real world, it does not work that way. As a simple, but I think a very important example, I am trained as a biochemist, I worked at the University of Colorado for eight years, I have worked at lots of other places, but that is one of the things I have done. During that eight year s working with peopl e who were highly trained scientists, as I try to remember it, we had at least six incidents where someone left the water running and the drain plugged one way or another. That meant that a highly expensive lab flooded and the water comes leaking through to the lab underneath destroying and many times very expensive, extremely expensive scientific equipment. In eight years, my memory is six of those occurrences. Now we happen to have been in sort of penthouse lab which meant we were on the top floor, so you might think we might have been immune from such a thing, but in a separate set of incidences, all of the H VAC equipment is up on that ceiling and I remember at least three times when th e guys who were in, maybe women, but the guys who were fixing the HVAC equipment di d something so our lab flooded and we lost very expensive, both results and sc ientific equipment so stuff happens. Life does not happen the way models tell you it is going to happen. We have better ways to do this. We aren't just talking about boiling water when we are burning coal. We can boil water too by usi ng concentrating, solar power. We can ship the electrons instead of shipping the coal over in nineteen century railroad system. We do not have as much coal as we have been told anyway, so all

Response: EPA acknowledges this comment. The purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and
p rovide requirements to pr event endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA clarifies that setting the scale of GS deployment and addressing the availability of coal are outside the scope of the Class VI GS rulemaking.

Commenter Name: Da g Nummedal Letter ID: 0533 Commenter Or g anization: Colorado Ener gy Resource Institute Comment ID: 21479Other EPA Comment Codes and Descriptions: 1660 1.3.6 Ecosystem impacts (soil, air, surface water) Comment: The last part then gets at the biosphere . A lot of people think I believe that the subsurface beneath our feet consis ts mostly of rocks only. It does not. Turns out that we have a very extensive community of microorga nisms that go deep down. In the deepest gold mines in South Africa, people are recovering microbes. And these microbes play a f undamental roles in the geoc hemical and radiological reactions. In fact in all different rocks, whether they be hard rocks where we get gold and silver and coppe r and whatnot, there are organisms related and are
p resent in both deep hard rock mines, those organisms that are found on limestones. We can look at that as potentially large carbon sequestration. Reservoirs contain a lot of bacteria, mi crobes in coal. Coal seams potentially are great places to store CO2 partly becau se some of the microbes will actually use the hydrogen as in the electron donor and then reduce the CO2 into methane. And we add hydrogen to the C and the O's and it produces methane and oxygen and water. And then if you can get that reaction to work in commercial and industrial settings in the subsurface, then you can actually use CO2 in the subsurface, in the coal seam s, the same way that we are increasingly using CO2 in algal farms. Algal biof uels which most people are strongly in favor of. Environmentally algal biofuels are probably very good and what you do of course, algae have to eat something, they eat CO2. Now if you can get the microbes in this subsurface, in the coal seams, to do the same thing basically converting that CO2 into methane and regenerate the methane, you can have a sustained
p roduction of methane which can be trapped and captured and used as it leaves a much cleaner fuel than coal and oils for a long time while you are storing CO2 in the process. I thi nk it is a very encouraging future technology.

And that will then also be a significan t part of the research that we are attracted, that we are here proposing.

Response: EPA acknowledges that there are potential risks associated with GS. The purpose of the Class VI requirements is to mi nimize and mitigate potential/ide ntified risks through proper site characterization, well cons truction, operation, monitoring, post-injecti on site care, and site closure and to ensure protection of USDWs. The Agency clarifies that, unde r SDWA authority, the requirements do not explicitly protect against CO2 leakage to the surface. However, the GS rule requires that CO2 injected for GS remain confined in the injection zone. Leakage outside of the injection zone/to the surface would be a permit violation.

In response to the comment suggesting "harne ssing biological activity"—such as underground microbes—to consume CO2, the Agency clarifies that the GS rule does not precl ude or endorse the use of specific technologies (e.g., microbes) for GS provided they are used in conjunction with appropriately sited, constructed, operated, and m onitored injection wells to ensure protection of USDWs.

Comment Code: 1320 1.1.3 General comments about GS



### Individual CommentsComment: Hi, MaryRose. My name is Rebecca, and I teach school for the Mendocino County Water Agency. I'm pretty conf used about carbon sequestration, and wondered if you could enlighten me. I have a difficult time picturing carbon, and wonder how it is sequestered. Is it in a gas or liquid form? If it's a gas and injected into the ground, wouldn't it be able to seep between rocks and get into our water supply? Is it stored in tank s? Someone told me it 's injected into coal, then buried? Could we inject it into old coal mines and seal it up? Even our most knowledgeable around here are stumped on this one. Thank you.

Response: GS is the process of injecting CO2 captured from an emission source (e.g., a power plant or industrial facility) into deep subsur face rock formations fo r long-term storage. It is part of a process known as “carbon capture and storage” (CCS). When in jected into an appropr iate receiving formation, CO2 is sequestered by a combination of trappi ng mechanisms, including phy sical and geochemical
p rocesses. Please see the preamble and materi als in the docket for additional information.

Comment: The Group Against Smog and Pollution (GASP) has three primary concerns regarding the geologic sequestration of CO2:

1. The potential for adverse chemical reaction of CO2 and its contaminants with the water/mineral environm ent of the host rock.

2. The need for Class VI wells given the advantages of CO2 enhanced recovery methods in existing Class II wells.

3. What agency will administer and overs ee the program? At least five agencies could be involved: EPA, DOE, DOT, USGS, and BLM.

Response: EPA acknowledges that there are potential risks associated with GS, including the potential that CO2 injection for GS may result in leachi ng of subsurface material s that could mobilize contaminants or compromise pore space, and ther efore injectivity. The purpose of the Class VI requirements is to minimize and mitigate potential or identi fied risks through proper site characterization, well cons truction, operation, monitoring, post-injecti on site care, and site closure. To ensure USDW protection and mitigate risks, the GS regulation requires the owner or operator of a Class VI well to submit data about the site (during the site characterization process), including information on the porosity, permeability, mineral ogy, and geochemistry of the inj ection and confining zones, along with information on the compatibility of the CO2 stream with fluids in the inje ction zone and minerals in both the injection a nd confining zones (§146.82). This data can help identify potential geochemical reactions that may occur between the injected CO 2 and the host geologic formation. Identification of
p otential reactions prior to inj ection would address concerns that formation of carbonic acid could dissolve potential limestone creating karst features.

Regarding EOR wells, EPA recognizes that the oil a nd gas industry has decades of experience injecting CO2 for the purpose of ER, and that sites used for ER may be suitable for GS and may be among the first GS sites. However, the Agency believes that the nature of CO2 injection for the primary purpose of long term storage poses different risks than inject ion for the primary purpose of ER, and therefore has developed new Class VI re g ulations to address these unique risk s. For example, the volume of CO2 Letter ID: 0102 Commenter Or g anization: Mendocino Count y Water A g enc y , State of California Comment ID: 21938

Commenter Name: Herbert Skolnick, Ph.D. Letter ID: 0110 Commenter Or g anization: Group A g ainst Smo g and Pollution, Inc. (GASP) Comment ID: 22035anticipated to be injected for long term storage is significantly greater than for ER operations. Reservoir
p ressure conditions will also be different, with Cl ass VI injection operations involving large volumes of CO2 and likely having higher pressures within their storage formations than Class II ER projects.

EPA clarifies that the Agency's UIC program or states with primar y enforcement responsibility will oversee GS projects.

For additional information on EPA’s final regul atory approach (including well construction requirements, monitoring, and post-injection site care and closure), please see the final rule and
p reamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1940 1.4.4.3 Consultations with Industry; experience with other wells Comment: EPA has correctly recognized that wells are a fundamental component of a geologic storage system that successfully ensures the containment of stored CO2. As such, we agree that having appropriate well design, construction & operating requirements are critical to the deli very of secure storage of CO2.

Oil and gas operators have decades of experience, via past and existing operations, in constructing an d operating EOR/EGR wells in a safe and secure way. For existing EOR projects and wells, Class II requirements have proven to be sufficient at ensuring the necessary protection of USDWs, and, therefore, analysis of the experiences and performa nces of these Class II CO2 EOR wells should inform the requirements for new Class VI wells.

Response: EPA recognizes that the oil and gas industry ha s decades of experience injecting CO2 for the
p urpose of ER, and that sites used for ER may be su itable for GS and may be among the first GS sites. Some of the research that informs the final GS rule was conducted at ER sites. EPA also recognizes that a by-product of ER activities is that a certain percentage of the CO2 is trapped in the receiving formation.

In addition, EPA is using an adaptive approach to regulating GS under the UIC Program. Even after finalization of the GS re gulation, the Agency plans to collect a nd review data every six years on GS
p rojects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Comment: Thank you for the opportunity to speak today. My name is Iain Wright. I work for BP and I manage the industrial-scale CO2 geo-sequestration project at In Salah in Algeria. BP appr eciates EPA's efforts to creat e a regulatory framework for industrial-scale CO2 geo-se questration in the US.

At In Salah, BP and its partners (Sonatrach and StatoilH y dro) have, for the last Commenter Name: Brian Williams Letter ID: 0116 Commenter Or g anization: BP Alternative Ener gy Comment ID: 22049

Commenter Name: Iain Wright Letter ID: 0118 Commenter Or g anization: BP Alternative Ener gy Comment ID: 22064four years, been sequestering around 1 million tonnes/year CO2 in a deep saline formation, which is down-dip of a produci ng gas field. CO2 storage at In Salah is permitted under Algerian hydrocarbon regul ations and we have learned a number of lessons that could be beneficial fo r the development of geo-sequestration regulations in the US.

My comments will address three issues:

1. Well Design,

2. Monitoring and

3. The Timeframe for Site Closure

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional inform ation on EPA’s final regulat ory approach (including well construction requirements, monitoring, and post-inje ction site care and closur e), please see the final rule and preamble as well as the rulemaking docket.

Comment: - Page 43498. Second paragraph on that page . "However, some CO2 releases from injection activities have been documented." Crystal Geyser is not an "injection activity" as that term is used in the c ontext of this Class VI rule. The text in that paragraph makes it clear that th e CO2 which erupts from Crystal Geyser is from "improper well pl ugging." It is technically inaccurate, misleading and
p rejudicial to start off this paragraph by saying "some CO2 releases from injection activities have been documented."

Response: EPA agrees that the Crystal Geyser site is not associated with injection. However, this incident demonstrates that ab andoned or improperly plugged boreholes can serve as conduits for migration of fluids to USDWs. It is for this reas on that the final rule includes requirements related to
p erforming corrective action on all deficient wells within the AoR at §146.84, and proper injection well construction that meets the goals of §146.86.

Comment: - Page 43495, third column, under "II What is EPA Proposing?" I believe the IPCC Special Report on Carbon Dioxide Ca pture and Storage (IPCC SR on CCS) and/or more recent peer reviewed papers can shed light on the timeframes under which primary and secondary trapping mech anism begin to operate. Adding some quantification to this point would likely help stakeholders better understand and be more familiar with CO2 storage. Consider adding something like "Some of these trapping mechanisms be gin as soon as the CO2 is injected into the host formation while others take hundred to thous ands of years to run their course." I believe one could cite the IPCC SR on CCS to subs tantiate that point. Commenter Name: James Doole y Letter ID: 0156 Commenter Or g anization: Joint Global Change Research Institute, Pacific N orthwest National Laborator y Comment ID: 22656

Commenter Name: James Doole y Letter ID: 0156 Commenter Or g anization: Joint Global Change Research Institute, Pacific N orthwest National Laborator y Comment ID: 22672Response: EPA agrees that the IPCC study mentioned is informative. The IPCC report is cited extensively in the preambles to the proposed and fina l rules, and is also available in the rulemaking docket.

Comment: 5. APPA believes that new power plants designed for geologic sequestration should be planned for sequestration to be conducted for the "lif e of the plant"- which can be as long as 60 years. However, APPA believes that if some type of lateral or vertical migration of the CO2 or other substances (such as brine, metals, drilling muds, cement from well failure) is dete cted and believed to be
p otentially harmful to the underground s ources of drinking wa ter (USDW), that the power plant or power plants supplyi ng the CO2 to the injection site(s) should be given an "infeasibility exempt ion[FN3]" for sequestration of its CO2. This exemption should enable the power pl ant to continue to operate without carbon dioxide injection in that location. W ithout this "infeasibility" or "back out" clause for geosequestration, it is highly unlikely that communities would build power generating facilities with carbon capture and injection systems that could cost at least $2 bi llion dollars (2008 dollars) or be able to obtain financing if the plant was not expected to operate for the full 50-60 years. The financial risks for closure of a power gene rating plant or multiple plants in a region would simply be too enormous. AP PA does not believe that anyone should
p resume that the CO2 from power plants to be injected into in situ or distant geology should be presumed to exceed 50% of the total CO2 in the first few decade of the commercial deployment. A PPA has no notion that the future fossil
p ower plants with CCS will be carbon neutral given the la rger volume of coal to be consumed in the gasificat ion process in order to make up for parasitic power losses.

[FN3] For the first generation plants, the "infeasibility exemption" should extend beyond infeasibility of the carbon capture operations of the power plant.

Response: EPA clarifies that regul ating power plants is outside the scope of the UIC GS rulemaking, and that GS rule does not require any faci lities to capture and/or sequester CO2.

EPA also clarifies that the intent of the Class VI regulations is not to promote or encourage the use of GS, but, instead to ensure pr otection of USDWs where GS technologies are deployed.

Comment: The EPA’s proposed rule asks for comment on many issues which are new to the
p ower sector. EPA does its best to tease out what we know from the use of CO2 injection/recycling fr om the oil and gas sector and try to apply some of these concepts to the future power sector part ies who might need to build coal-fired electric generating plants but would be required to reduce emissions of carbon dioxide through the combination of carbon cap ture technology at the plant and GS at an injection site.

Carbon sequestration can emplo y an y of several ph y sical, chemical, or biolo g ical Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23377

Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23384p rocesses to isolate CO2 from the atmo sphere, on a long-term basis. Carbon sequestration can be terrestrial and geol ogical. As part of the Earth’s carbon cycle, terrestrial sequestration uses ve getation and the soil as carbon sinks. There are both technical and non-technical challenge s to sequester large quantities of CO2 in subsurface reposit ories. The technical challenges are exacerbated by a lack of experience with processes on an appropriate scale, or in geologic formations that have no history of oil and gas production. The nontechnical challenges - in the form of legal and regulatory issues - are as significant as the technical uncertainties. But APPA supports research in order to assist us to ma ke these changes.

The amount of CO2 that could be required to be sequestered is enormous. The generation of power by coal-fired power pl ants in the U.S. produces 1.5 billion tons of CO2 that, when compressed to supercritical conditions, comprises a volume that exceeds that equal to U.S. oi l consumption. The task of transporting and managing this volume of material is complicated by the need to operate the transport in a pipeline at 2,000 psig to maintain CO2 in a fluid state in these specialty pipelines.

APPA does not question the viability of the technology of carbon dioxide injection for enhanced oil and gas re covery in production fields. Any questioning about the technology in the cont ext of these APPA comments pertains to new large scale power pl ant parties which would likely be built outside the geologic formations suitable for oil and gas recovery. While the proposed rule asked for comments on the impacts on other industries, these APPA comments focus on power plants. We don't offer comments on carbon separation and injection/storage for ethanol plants, chem ical companies, cement factories, or coal bed methane plants that might have similar opportunities to inject CO2. APPA has no comments on more shallow me thane recovery from coal operations.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket. As described above, the GS rule does not require any facilities to capture and/or sequester CO2.

Comment: Our comments pertain to large scale power plant applications and those much larger CO2 injections a nd storage in geologic form ations. There may be opportunities in the early years for th e placement of coal plants for geosequestration in the shadow of the oil and gas industry where there would be opportunities for EOR/EGR. APPA encourages this and believes that this may be beneficial to many parties-including the power sector. If all new coal power
p lants could be built over geologic formati ons that have oil and gas recovery operations or where the CO2 could be stored in depleted wells, the economics would be far more favorable for the power s ector. However, even if that were the case, the drinking water protection issues do suggest some initial caution in site selection.

Response: EPA acknowled g es the comment. As described above , the GS rule does not require an y Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23386facilities to capture and/or sequ ester CO2. Please see the remainder of EPA’s responses to this comment for further details.

Other EPA Comment Codes and Descriptions: 5600 2.11 Comments related to UIC Program primacy for Class VI wells Comment: Because state regulators in approximately five or si x states have worked extensively with Owners or Operators of UIC Class V experiment al CO2 wells they have familiarity with envir onmental, geologic, and financial concerns specific to a given region, their adoption and tail ored implementation of the CO2 GS rules will be crucial to the success of the Program.

Response: EPA acknowledges the expertise of existing Stat e, Tribal, and Territorial programs that implement the UIC requirements unde r Section 1422 of the SDWA (C lass I, III, IV, and V wells (particularly Class V experimental technology wells)) and state oil and gas agencies that have been regulating Class II UIC wells for decades under section 1425 of SDWA. These agencies already understand the technical and administrative issues involved in constructi on, operation, injection and
p ermitting as well as, in the case of Class II operators issues re lated to CO2 injection, subsurface operations, and pipeline transport. EPA believes that existing programs can adapt this expertise to the new requirements for Class VI wells and will be able to develop a primacy application for Class VI wells under section 1422 of SDWA.

Many of the tools, resources, expert ise, and infrastructure currently exist within States to effectively and efficiently manage GS pr ojects. Additionally, States can use mult iple authorities beyond those afforded under the SDWA and UIC regulations including surf ace access and land rights, unitization of fields,
p ore space ownership, mineral rights, site safety and emergency preparedne ss, and maximization of State oil and gas res ource exploitation.

Comment: Regulation of GS under the UIC program will have a direct impact on Ameren,
p articularly our fossil-fired faciliti es involved in the production of electricity and we have a substantial interest in EPA's development of a realistic and cost-effective UIC progr am for Class VI CO2 GS wells

Response: EPA acknowledges the comment. EPA clarifies that the GS rule does not require any facilities to capture and/or sequ ester CO2. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EP A’s final regulatory approa ch, please see the final rule and preamble as well as the rulemaking docket.

Comment: The development of a viable CO2 capture and sequestration regulatory program has been cited by many as a prer equisite to the implementation of energy reform initiatives involving carbon reduction measures on both the federal and state level. Because the electric utility industr y has been identified as the primary industrial sector tar g eted for re g ulation under future carbon capture and Commenter Name: Theresa Pugh Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23403

Commenter Name: Paul Pike Letter ID: 0198 Commenter Or g anization: Ameren Corporation Comment ID: 23936

Commenter Name: Paul L. Carpinone Letter ID: 0212 Commenter Or g anization: Tampa Electric Compan y Comment ID: 22895sequestration (CCS) regulations, the elect ric utility industry has a direct and substantial interest in EPA's development of a realistic and cost-effective UIC
p rogram for Class VI CO2 GS wells.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: I. General Statement:

The North American Coal Co rporation believes that a diverse fuel supply is imperative to the economic health of our country. Affordable and reliable electricity, which is created in an envi ronmentally friendly manner, forms the cornerstone for our country ’s economy and creates a h ealthy society. Lignite coal is a vital part of this diverse fuel supply.

Coal and the low-cost electricity it pr ovides are vital to the reliability of the U.S. electric supply system, and to the economic vitality of the U.S. economy. Coal production and related elec trical generation account for some hundreds of billions of dollars of U.S. gross domestic output, over a hundred billion dollars of annual household income, and millions of jobs.

Lime rock in Florida is used as aggregat es in the construction of buildings and roads and as a feedstock for cement production. As such, lime rock is a critical component for the growth of the region: It is literally the foundation for any building project.

Coal-fired power plants and cement ki lns all produce carbon dioxide (CO2). If legislation or regulations are promulgated that restri ct the emission of carbon dioxide, then many of these facilities will need to capture and sequester CO2. Thus, NAC’s customers will be imp acted by the proposed regulations.

Furthermore, as a natural resource produc er, NAC will be directly impacted by any rule that affects the subsurface of the Earth. Lignite-fired power plants and cement kilns are all "mine mouth" faci lities. That is to say, the mine is literally next door to the facility. If the facility (and/or others in the area) sequester CO2 in subsurface form ations, then lands and resources controlled by NAC could be adversely affected.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: developmental aspects of CCS activities in both the U.S. and Canada. As we noted in Commenter Name: Dennis R. James Letter ID: 0214 Commenter Or g anization: North American Coal Corporation (NAC) Comment ID: 22956

Commenter Name: Michael Moore Letter ID: 0265 Commenter Or g anization: North American Carbon Capture & Storage Association (NACCSA) Comment ID: 22848our oral and written te stimony presented at EPA's September 30, 2008 public hearing on the proposed rules, policymakers and companies are, and should be, like the members of NACCSA,interested in CCS technology because it holds significant
p romise as a tool to manage CO2 emissions as well as to maximize energy recovery.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1280 1.1.2.1 General comments on climate change/ global warming Comment: Assessment of the Proposed Rule The proposed rule repeatedly re ferences climate change mitigation by the inj ection of CO2 as the justification for the need for the new class of injection well:

Summary: "EPA is proposin g Federal requirements under the Safe Drinking Water Act (SDWA) for underground injection of ca rbon dioxide (CO2) for the purpose of geologic sequestration (GS). GS is one of a portfolio of options that could be deployed to reduce CO2 emissions to the atmo sphere and help to mitigate climate change."

And "If finalized, this proposal would he lp ensure consistency in permitting underground injection of CO2 at GS opera tions across the U.S. and provide requirements to prevent endangerment of US DWs in anticipation of the eventual use of GS to reduce CO2 emissions."

In Part II "What is the EPA Propos ing" the proposition reiterates:

"In addition to protecting USDWs, today’s proposed ru le provides a regulatory framework to promote consistent approach es to permitting GS projects across the U.S. and supports the development of a key climate change mitigation technology."

Under Part II A. "Why Is EPA Proposing To Develop New Regulations To Address GS of CO2?" Part II. Section 2, states: Th e Intergovernmental Panel on Climate Change (IPCC) has concluded that much of the warming in recent decades is very likely the result of human activities (IPCC, 2007). The burning of fossil fuels (e.g., from coalfired electric plants and other sources in the electricity and industrial sectors) is a major contri butor to humaninduced greenhouse gas emissions.

Fossil fuels are expected to remain the ma instay of energy production well into the 21st century, and increase d concentrations of CO2 ar e expected unless energy
p roducers reduce the CO2 emissions to the at mosphere. The capture and storage of CO2 would enable the continued use of coal in a manner that greatly reduces the associated CO2 emissions while other safe and affordable alternative energy sources are developed in the coming decade s. Given the United States’ abundant coal resources and reliance on coal for power g eneration, CCS could be a ke y Commenter Name: Mary Munn Letter ID: 0273 Commenter Or g anization: Fond du Lac Reservation Comment ID: 24082mitigation technology for achieving domestic emissions reductions"

And:

"Congressional climate change legislative proposals (the McCain-Lieberman bill S. 280, the Bingaman-Specter bill S. 1766, and the Lieber man-Warner bill S. 2191) indicate that CCS has th e potential to play a signi ficant role in climate change mitigation scenarios."

And:

"Today’s proposal provides a regulatory frame work to protect USDWs as this key climate mitigation technology is developed and deployed."

The allusion of mitigating climate change or reducing CO2 emissions by geologic sequestration cannot be fairly used as pe rsuasive point for this rule without
p roviding data demonstrating the mass balance of energy and carbon dioxide in the whole system. A great d eal of analysis has been completed and posted on the docket of cost and incremental cost within the proposed rule for CCS and GS implementation but no analysis is made in terms of the actual amount carbon dioxide that will be sequestered in relation to the amount of carbon dioxide emitted throughout the process (Cost: EPA-HQ-OW-2008-0390- 0073 and EPA-HQOW-2008-0390-0094).

A mass balance of the participating foss il energy processes, generating the CO2, must be evaluated to determine if any real reduction in CO2 can be made. CO2 is emitted during the excavation and transport of the fossil fuel to a power plant. Additional power will be re quired, and will emit additional CO2, to provide the energy to extract the CO2 from the emissi on stream, to compress, transport, and to inject the CO2 into a geologic formation.

Response: EPA clarifies that the Class VI GS requirements are designed to ensure consistency in
p ermitting underground injection of CO2 at GS oper ations across the United States and provide requirements to prevent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. The requirements apply to owners or operators of inject ion wells used to inject CO2 for
p ermanent storage.

GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in thes e technologies is outside the scope of the Class VI GS rulemaking. The Class VI GS requirements are designed to ensu re that, where GS is deployed,
p rojects are permitted, sited, constructed, operated, a nd closed in a manner that protects USDWs from endangerment.

Comment: We are writing in relation to EPA’s ongoing efforts to regulate the geologic sequestration of carbon dioxide (GS). We believe that a truly sustainable energy system will utilize opportuni ties to increase energy e fficiency and renewable

ener gy first and foremost. However, the vast ma j orit y of our ener gy in the U.S. Commenter Name: Scott Anderson Letter ID: 0295 Commenter Or g anization: Environmental Defense Fun d Comment ID: 26136and worldwide is still produced from fo ssil fuels, and this is likely to continue for some time. Faced with a rapi dly changing climate, we believe that carbon capture and geologic sequestration (CCGS) can and should play an important role in reducing greenhouse gas emissions in the near term.

Response: EPA acknowledges the comment. EPA clarifies th at the purpose of the UIC GS regulation is to ensure that GS is conducted in a manner that protects USDWs from endangermen t. EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in thes e technologies is outside the scope of the UIC GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, projects are permitted, sited, constructed, operated, and cl osed in a manner that protects USDWs from endangerment.

Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: It is clear that industry and people beli eve that CO2 sequestration is possible even though there are no long- term studies available -- for the storage over long periods of time.

Response: The UIC Program’s authority under the SDWA focuses on ensuring that GS projects are
p ermitted, sited, constructe d, operated, monitored, and closed in a manner that is protective of USDWs. Ensuring storage capacity is outside the scope of the UIC GS rulemaking.

EPA clarifies that other federal agencies (e.g., DO E and the U.S. Geological Survey) have conducted research on available storage capacity and determinations of the feasibility of capturing and storing CO2 at the scales needed to address climate change. These agencies, along with private entities, have identified large ar eas for potential sequestration in capaci ty studies. For example, in 2008, USGS initiated development of a methodology for estimating th e capacity to store CO2 in geologic formations of the US. In 2010, USGS finalized and published a risk- b ased methodology for GS capacity estimation. "A Probabilistic Assessm ent Methodology for the Evaluation of Ge ologic Carbon Dioxide Storage" is available at http://pubs.usgs.gov/of/2010/1127/.

Comment Code: 1330 1.1.3.1 Support use of GS in general



### Individual Comments

Other EPA Comment Codes and Descriptions: 1680 1.3.8 Don't overstate risk, don't stigmatize CO2 Commenter Name: Lee Spra g ue Letter ID: 0505 Commenter Or g anization: Sierra Club Comment ID: 21234

Commenter Name: Karl R. Moo r Letter ID: 0109 Commenter Or g anization: Southern Company, on behalf of Edison Electric Institute (EEI) Comment ID: 21992Comment: Key Messages

We have two key messages for EPA today:

First, the regulations can and should prom ote the development and deployment of carbon capture and storage while protec ting underground sources of drinking water without unduly stigmatizing carbon dioxide injection and storage. Carbon dioxide has been injected for years for e nhanced oil recovery and enhanced gas recovery without incident.

Response: EPA does not believe that the GS regulati on stigmatizes CO2 inj ection. However, EPA believes that injecting large volumes of CO2 fo r GS poses unique challenges that, if not properly managed, could endanger drinking wa ter sources and have other advers e impacts. The final, tailored, Class VI requirements address the large volumes of CO2 injected, its buoyancy, potential corrosivity in the presence of water, and potential impurities in the CO2 stream. In addition, EPA expects the tailored
p ermitting, siting, construction, opera tion, monitoring, and post-injection site care requirements in the GS rule to prevent leakage from inje ction formations and protect USDWs.

EPA believes that building upon the existing UIC requirements (e.g., Class I and Class II well requirements) to develop the Clas s VI GS regulation provides a foundation for protecting USDWs based on success, field experience, and lessons learned about CO2 injection in other applications. Class I well owners or operators have experi ence with site characterization, well construction, and monitoring
p rocedures and technologies that are applicable to Class VI wells. Cl ass II ER well operators have experience with managing the unique properties of CO2. To successfully flood a hydrocarbon field with CO2 during an ER operation, the behavior of injected CO2 must be well understood.

Comment: Energy (DOE). We share the EPA’s belief th at CO2 sequestration has the potential to improve air quali ty. We further believe that the best way to promote economical geosequestration of CO2 initially is to link captured CO2 with oil reserves, producing increased petr oleum recovery efficiencies.

Texas is a leader in enhanced oil r ecovery using CO2. Texas possesses an extensive oil and gas pipeline infrastruc ture capable of transporting CO2 to various sequestration sites. The first CO2 flood occurred in 1972 in West Texas. In 2005, over 160,000 barrels of oil per day were produc ed with CO2 EOR in Texas. The RRC has permitted over 11,200 CO 2 injection wells, with over 5,400 of those being currently active. The 50 active CO2 enhanced oil recovery projects in West Texas represen t about 50 percent of total CO2 flooding activity worldwide. CO2-driven EOR has grown steadily since 1985 and now accounts for over 15 percent of the average yearly oi l production in Texas. The oil industry has experienced a supply shortage of CO 2 over the past few years. Finding new sources of CO2 will alleviat e that shortfall and result in an increase in oil
p roduction. The current shortage is about 0.5 billion cubic feet per day, with industry consuming the avai lable 1.5 billion cubic f eet per day. Increased availability of anthropogenic CO2 could accelerate this production. In April of 2004, the University of Texas Bureau of Economic Geology identified at least 31 billion barrels of oil in Texas that ar e recoverable using CO2-driven EOR. Commenter Name: Leslie Savage Letter ID: 0122 Commenter Or g anization: Railroad Commission of Texas (RRC) Comment ID: 24730The RRC has primacy over Class II well s and Class III brine mining wells in Texas. Texas has been regul ating injection wells since the 1930s. With nearly a

Response: EPA clarifies that injection of CO2 for the pur poses of enhanced oil and gas recovery will continue to be permitted under the Class II program, as long as any oil or gas production is occurring. The UIC GS requirements will apply to well s used for the purpose of long-term GS.

Please see the remainder of EPA’s responses to this comment for further details.

For additional information on EPA’s approach to well s that are transitioning fr om ER to GS, see the discussion of Class II wells under “H ow Does This Rule Affect Exis ting Injection Well s Under the UIC Program?” in the preamble to the final GS rule.

Comment: As the owner of power generation facili ties, SEGNA respectfully submits the following comments for consideration by EPA. SEGNA supports efforts to curb greenhouse gas emissions, including research and investment in carbon capture and sequestration (CCS) technology.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1000 1. General and Administrative Comments Comment: ODEC supports the comments of the Ca rbon Capture and Sequestration Alliance (CCS, or the Alliance) on the proposed UIC regulations. The CCS Alliance is a coalition of entities, spanning a number of economic sectors, that share a common interest in removing impediments to investment in and development of CCS, as well as mitigating the potential risks associated with the deployment ofthis technology.[l] Its purpos e is to promote development of policy by the states and the federal government to appropriately ad dress risks and potenti al liabilities, thereby enabling the further development and increased deployment of CCS. The CCS Alliance believes these technologies can be developed while protecting underground water resources, significantly reducing global and U.S. greenhouse gas ("GHG") emissions, and enhancing u.s . energy security. The Alliance's
p urpose is to consider ways ofpromoting the development and use ofCCS technologies and to support effOlis by th e private sector, states, the federal government, non- governmental organizations and others, to help ensure that these technologies can be de veloped and widely, efficien tly and cost-effectively deployed.

Response: EPA clarifies that the purpose of the UIC GS regulation is to ensure that GS is conducted in a manner that protects USDWs from endangerment. EPA agrees that GS is one technology in a portfolio of options, including energy conserva tion, efficiency improveme nts, and the use of alternative fuels and renewable energy sources, th at could be deployed to reduce CO2 emissions. Commenter Name: Carl Carlsson Letter ID: 0131 Commenter Or g anization: SUEZ Ener gy Generation NA, LLC Comment ID: 21524

Commenter Name: Kenneth Alexande r Letter ID: 0146 Commenter Or g anization: Old Dominion Electric Cooperative (ODEC) Comment ID: 21726Please see the remainder of EPA’s responses to this comment, and CCS Alliance’s comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and
p reamble as well as the rulemaking docket.

Comment: Simply stated, CCS involves separating and capturing CO2, transporting the CO2 by truck or pipeline to an underground storage location, and injecting and storing it in underground geologic formati ons. While CCS is just one of many climate change mitigation options,[FN2 Ot her options include energy efficiency improvements, a switch to less carbon-in tensive fuels, nuclear power, and renewable energy sources.] it will be a vi tal component of any U.S. strategy for addressing climate change given our relian ce on coal for almost half of our electricity production. Likewi se, CCS could have a substa ntial role in reducing CO2 emissions from developi ng countries, such as India and China, where CO2 emissions are projected to increase e xponentially in connection with their growing energy needs.

Response: EPA clarifies that the purpose of the UIC GS regulation is to ensure that GS is conducted in a manner that protects USDWs from endangerment. EPA agrees that GS is one technology in a portfolio of options, including energy conserva tion, efficiency improveme nts, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissi ons. Please see the remainder of EPA’s responses to this comment for further de tails. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1410 1.2.1 Comments in support of EPA/rulemaking Comment: As part of the U.S. strategy for addressi ng climate change and implementing CCS, EPA has proposed a first-time rule unde r the SDWA for sequestering CO2 in geologic formations. The proposed rule is based on EPA’s existing regulatory framework for its UIC Progr am and proposes a new cate gory of injection well (Class VI) along with several technica l criteria for its implementation.

The Chamber strongly supports the developm ent and deployment of carbon capture and sequestration technology, and we appl aud EPA for its extensive public outreach, stakeholder dialog, and public wo rkshops on this issue. Nevertheless, in order to ensure that this proposed rule accomplishes its objectives to
p romote a CCS regulatory framework and suppor t "the development of a key climate change mitigation technology ," the Chamber offers the following comments on
p otential legal, economic, regulatory, and technical barriers to CCS deployment that EPA should consider befo re finalizing this rule.

Response: EPA agrees that input of and participation by a wide spectrum of stakeholders is a vital component of a successful rulema king. The Agency appreciates the de gree of cooperation, participation, and active dialogue between the EPA and stakeholders and will continue to work with stakeholders and experts as it implements the GS rule.

EPA believes that the creation of a new in j ection well class (VI) under the existin g UIC Pro g ram is Commenter Name: William Kovacs Letter ID: 0148 Commenter Or g anization: U.S. Chamber of Commerce Comment ID: 21748

Commenter Name: William Kovacs Letter ID: 0148 Commenter Or g anization: U.S. Chamber of Commerce Comment ID: 21749necessary to enable deployment of GS as a climat e change mitigation tec hnology in a manner that
p rotects USDWs from endangerment. EPA agrees th at the UIC Program, under the authority of the SDWA, provides a strong framework for regulating injection of CO2 for GS and adds that the GS regulation tailors the UIC requirements to address the unique issues associated with large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurit ies in captured CO2, and its mobili ty within subsurface geologic formations.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

Other EPA Comment Codes and Descriptions: 1000 1. General and Administrative Comments Comment: To whom it may concern:

I appreciate the opportunity to provide comments on the proposed rules for federal management of geologic sequestrati on of CO2 in DocketID No. EPA-HQOW-2008-0390. This is a unique opportunity to broaden our national public policy foundation by melding new federal ener gy policy with responsible natural resource policy and, in so-doing, expand economic opportunities and potentially reduce the amount of CO2 that is introduced into the atmosphere. As currently written, provisions of the proposed rules re lated to the suitability of specific reinjection locations ca use serious concern.

Wyoming has been proactive in its stewardship of all state resources and we recognize the need for environmental re gulation. Over the years we have demonstrated our regulatory capabilit y by meeting and often exceeding EPA standards in managing activities that impact public health, public safety and all public resources. We are eager to co llaborate with the federal government yet again, to craft rules that work not only for the interests of the nation but that also work dire ctly for the people of Wyoming. Within the framework of this collaborative undertaking, the importanc e of including local expertise and knowledge into the regulation of CO2 sequest ration is necessary to ensure public safety while also providing new grow th opportunities for a vibrant new industry.

Response: EPA recognizes the importance of states having primacy for GS wells given the variety of
g eolo g ic settin g s in which GS will be applied. EPA reco g nizes that State, Tribal, Territorial, and DI UIC Commenter Name: Dave Freudenthal Letter ID: 0150 Commenter Or g anization: State of W y omin g Comment ID: 22216p rogram Directors are in the best position to evaluate the unique issues related to well depth, geology, and hydrogeology that are posed by a Class VI well. Some degree of flexibility is needed for Class VI wells because each decision made will be site-specifi c and conditions will differ from state to state. The GS rule balances the need for these site-speci fic decisions with the n eed for minimum Federal requirements to ensure national consistency while ensuring the protection of USDWs.

EPA also believes that providing states the fl exibility to obtain prim acy for Class VI wells independently of other well classes can help foster effective ma nagement of CCS. EPA believes that allowing independent Class VI primacy may encourage states to take responsibility for implementation of Class VI regulations and provide for a more co mprehensive approach to managing CCS projects by
p romoting the integration of GS activities under SDWA into a broader framework for managing CCS. Furthermore, GS operations involve ancillary activ ities (e.g., pipeline operations, pore space ownership, land use rights, and surface access) fo r which states can call upon other aut horities that exist at the state level (but outside UIC au thority) to provide a mo re comprehensive CCS management approach. The Agency will allow independent primacy for Class VI wells under §145.1(i) of the final GS rule.

For additional information on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket. EPA is using an adaptive approach to regulating GS.

Other EPA Comment Codes and Descriptions: 1350 1.1.3.3 Comments on the need for GS technology Comment: Given public concern over climate cha nge, pending legislative proposals to sharply curtail carbon dioxide (CO2) em issions, and estimates that energy companies based in Houston and elsewher e could use anthropogenic CO2 to produce billions of barrels of oil that w ould otherwise not be produced, the Partnership believes it is important that carbon capture and storage (CCS) technologies become commercially available as soon as possible. In the near term, strategies employing CO 2 sequestration for Enhanced Oil Recovery (EOR) will help commercialize the carbon capture tec hnology and will help demonstrate the technology necessary for long-term storage of CO2 as a predicate to larger-scale CCS projects. The Partnership strongly s upports regulatory efforts to strengthen incentives for EOR and othe r technologies focused on meeting the challenge of global warming while providing energy and e nhancing our region's economic life.

Response: EPA clarifies that the intent of the Class VI re gulation is not to promote or encourage the use of GS, but, instead to ensure protection of USDWs where GS technologies are deployed. In addition, EPA clarifies that injection of CO2 for the purposes of enhanced oil and gas recovery will continue to be
p ermitted under the Class II program , as long as any oil or gas pr oduction is occurring. The UIC GS requirements will apply to wells used for the purpose of long-term GS.

Other EPA Comment Codes and Descriptions: 1420 1.2.1.1 Support the GS rulemaking Comment: Carbon capture technologies have been deve loped and there is reason to expect that CO2 can be successfully stored on a long-term basis in properly selected and managed geologic formations. Full comm ercialization will require additional economic incentives and earl y demonstration pro j ects at lar g e scale. In Commenter Name: Jeff Mosele y Letter ID: 0155 Commenter Or g anization: Greater Houston Partnership (GHP) Comment ID: 21252

Commenter Name: Jeff Mosele y Letter ID: 0155 Commenter Or g anization: Greater Houston Partnership (GHP) Comment ID: 21253addition, it is important for business planning purposes that the Environmental Protection Agency (EPA) soon adopt reasonable rules governing CO2 storage in geologic formations.

Response: EPA believes that the creation of a new in jection well class (V I) under the existing UIC Program is necessary to enable the use of GS as a climate change mitigation technology in a manner that
p rotects USDWs from endangerment. EPA agrees th at the UIC Program, under the authority of the SDWA, provides a strong framework for regulating injection of CO2 for GS and adds that the GS regulation tailors the UIC requirements to address the unique issues associated with large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurit ies in captured CO2, and its mobili ty within subsurface geologic formations.

Other EPA Comment Codes and Descriptions: 1420 1.2.1.1 Support the GS rulemaking Comment: The EPA is presently considering how CO 2 sequestration should be regulated under the federal Underground In jection Control (U IC) program. The Partnership is
p leased that this work is a priority for the agency. We encourage EPA to develop rules that:

1. Assure that sites are pr operly selected managed and monitored in order to
p rotect underground sources of drinking wa ter (USDW), especially sole source aquifers.

Response: EPA clarifies that the purpose of the GS rule is to protect USDWs from endangerment through permitting, siting, construction, operation, injection, and post-inject ion site care and site closure requirements that are tailored to address the unique nature of GS.

EPA clarifies that SDWA, under section 1422(b)(3)(9)(A), requires that the regulations of the Administrator "permit or provide for varying geologic, hydrol ogical, or historical c onditions in different states and in different areas within a state." EPA ha s provided the Director disc retion in applying the GS requirements, taking into account varying conditions, particularly with regard to the evaluation of site characteristics.

For additional information on site ch aracterization and testing and moni toring requirements, please also see the discussion of EPA’s Final Regulatory Approa ch in the preamble to the final GS rule.

Comment: The development of GS is an important st rategy within a portfolio of options for the Midwestern region to reduce greenhouse gas emissions. In 2007, we endorsed the Energy Security and Climate Stewardshi p Platform (Platform) that includes a broad range of measurable goals, policies and initiatives to transition the Midwest to a lower carbon energy economy. Pr iorities include th e development of energy efficiency, bio-based products and transportation, renewable electricity and advanced coal with carbon capture and sequestration (CCS).

Response: EPA a g rees that GS is one technolo gy in a portfolio of options, includin g ener gy Commenter Name: Jeff Mosele y Letter ID: 0155 Commenter Or g anization: Greater Houston Partnership (GHP) Comment ID: 21254

Commenter Name: M. Michael Rounds Letter ID: 0159 Commenter Or g anization: Midwestern Governors Association (MGA) Comment ID: 22223conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. Please see the remai nder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: The Midwestern region depends heavil y on coal-fired generation and has significant coal and oil resources. These resources are also located in close
p roximity to formations that are like ly suitable for geologic sequestration, specifically saline aquifers and depleted oil and gas fi elds. Thus, the Platform supports the development of a CO2 manageme nt infrastructure and demonstration and commercialization of la rge-scale geologic sequestration projects that take advantage of our region’s EO R potential. The Midwest has significant experience in both EOR and in the transport of CO 2 through pipelines. These EOR projects would be part of a broader CO2 management strategy to capture CO2 from various sources and effectively leve rage projects to build-out an infrastructure that could support long-term CO2 se questration across the region.

Response: EPA acknowledges the comment. EPA clarifies th at injection of CO2 for the purposes of enhanced oil and gas recovery will continue to be permitted under th e Class II program, as long as any oil or gas production is occurring. The UIC GS requirements will apply to wells used for the purpose of long-term GS.

Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: DTE Energy is a member of the Edison El ectric Institute (EEI) and the Utility Solid Waste Activities Group (USWAG) and endorses the comments filed by each in this docket. The developmen t of cost effective Carbon Capture and Sequestration (CCS) technology, in concert wi th regulations that allow flexible yet protective implementation are extremely important to our subsidiary -Detroit Edison, which has a fuel mix nearly 80% dependent on co al. Coal is domesti cally abundant and affordable. For those reasons, along with the need to comply with future regulations requiring the reduc tion of CO2 emissions, we would like to continue to utilize coal in our fuel mix in th e future and see CCS as an important element to accomplish that goal. We applaud EPA’s effort and initiative to take the first critical steps to establishi ng a regulatory framework for geologic sequestration. We appreciate the opport unity to provide input into the regulatory development process and hope that EPA will cons ider our comments that we feel will impact our company and also the commercial deployment and public
p erception about carbon capture and storage.

EEI and USWAG have done an excellent job of articulating the important general and specific technical comments which we anticipate EPA will seriously consider. DTE Ener gy submits the followin g hi g h level overview and interpretation of the Commenter Name: M. Michael Rounds Letter ID: 0159 Commenter Or g anization: Midwestern Governors Association (MGA) Comment ID: 22224

Commenter Name: Skiles Bo yd Letter ID: 0160 Commenter Or g anization: DTE Ener gy Comment ID: 21265issues that we believe are of ut most importance to the rulemaking.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment, EEI’s comment, and USWAG’s comment fo r further details. For additional information on EPA’s final regulatory approach, pl ease see the final rule and prea mble as well as the rulemaking docket.

Comment: The LEC's, along with our major members', participation in PCOR signals the importance of CCS technology and the need fo r the development of clear, flexible and appropriately tailored regulations that will facilitate th e development of and spur investment in CCS technology. To achieve this goal several general
p rinciples should be considered by EPA as it refines the proposed regulations.

Response: EPA recognizes the importance of providing clear, flexible, scalable, and appropriate regulations. EPA believes that th e GS regulation will provide certa inty to industry and the public by
p roviding consistency in requirements across the U.S. and transparency about what requirements apply to owners or operators. EPA clarifie s that the intent of the Class VI regulation is not to promote or encourage the use of GS, but, instead to ensure protection of USDWs wh ere GS technologies are deployed.

Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: 3. APPA wants geologic sequestration of CO2 to work. Geologic Sequestration might enable the power utilit y sector to use coal at future and existing power
p lants while reducing CO2 emissions. Howe ver, the technology is not yet fully commercially demonstrated and suitable geology may not be available in all states. This caution does not discourage us from wanting it to work or for supporting additional demonstration projec ts at DOE/NETL and in the private sector. Geosequestration opportunities in oil and gas states are probably the most optimal location for early adopters of CCS technology(s). APPA encourages the use of oil and gas fields for in jection of CO2 from power plants.

Response: EPA clarifies that the intent of the Class VI re gulation is not to promote or encourage the use of GS, but to ensure protection of USDWs wh ere GS technologies are deployed. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1610 1.3.1 Risks to USDWs Comment: Geologic sequestration into all geologic formations must be considered by electric utilities in their lon g -term plans for future fossil-fuel electricit y Commenter Name: Sandi Tabo r Letter ID: 0162 Commenter Or g anization: Li g nite Ener gy Council (LEC) Comment ID: 21293

Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23375

Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23382generation while also weighing the ne ed to protect public drinking water supplies. Protection of drinking water suppl ies, for some communities, may mean that inadequate surface water supplies ma y require that the city (or private utility) may require usage of groundwater in future years which may not appear to be "drinkable" under t oday’s presumed costs and te chnological (pump and treat or desalination) limitations. Our colleagues in the municipal drinking water operations remind us that Americans are currently drinking water which, in many locations, was undrinkable only 5-10 years a go. While most American cities in the east provide drinking water made up larg ely of surface water, more than 90% of all drinking water systems (priva te and public) use some amount of groundwater to make up for shortages. Acknowledging this does not mean that geosequestration should not be allowed. It simply requires common sense decision making at the local and regional level by power plants and th e state directors as to the best placement of geosequest ration plants or off-site injection formations.

Response: The Agency acknowledges commenter concerns about water resources and future water resource availability. Th e primary goal of the UIC Program under the SDWA is to protect USDWs from endangerment in order to ensure a reliable supply of drinking water for the American public. The GS rule, as part of the UIC program regulations, continues the program’s mandate and mission of ensuring the protection of USDW s. EPA expects the tailored perm itting, siting, construction, operation, monitoring, and post-injecti on site care requirements in the GS rule to prevent leakage from injection formations and protect USDWs.

Other EPA Comment Codes and Descriptions: 1610 1.3.1 Risks to USDWs; 1800 1.4 Scientific Background/Informing the Proposal Comment: Our comments here should not deny the vi ability of CCS in some subsurface locations nor be read as APPA’s view that geologic sequestration works in all geologic locations or for all power plants. There is a gr eat deal that we do not yet know about the wide variety of geologi c formations to know that there are no risks to USDWs or that we could identify specifically what those risks might be. APPA hopes that on-going private and public research in the United States, Canada, Australia, and Europe will affi rm that there are no risks to drinking water supplies or that the risks are so truly negligible that there is no reason to hesitate to use this technology. But we cannot presume that there are no risks simply based upon the commercial and technical success in CO2 recycling in Class II injection locations that are ma naged as production fiel ds. It has been
p resumed that because the CO 2 injections began in the Permian Basin of West Texas in the late 1970s that the CO2 from those tertiary recovery fields (for oil or gas) is actually still in the formation. In most cases the CO2 was recycled and used in different produc tion operations. Even if the CO2 was injected 25-35 years ago, the CO2 may not still reside or remain in storage there. Because we have not seen large st orage fields where the CO2 was stored for 10-30 years on a sustained basis, ther e is not as much known about the geologic formations, the adequacy of holding capacity and subsur face impacts as we would like to know. Also, in many cas es, those oil or ga s production fields are regulated differently than a newly established long-term GS formation would b e re g ulated if it were owned/operated b y a power compan y

. Commenter Name: Theresa Pugh Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23387Response: EPA agrees with the commenter that the risks i nvolved in GS projects are different than the risks associated with Class II activities. EPA believes that GS is sufficiently distinct from Class II ER operations to warrant the tailored requirements in the GS regulation. For example, the volume of CO2 anticipated to be injected in Cla ss VI wells is significantly greater than for Class II wells. Reservoir
p ressure conditions will be differen t, with Class VI injection operati ons involving large volumes of CO2 and likely having higher pressures within their storage formations than Class II ER projects. Therefore, Class VI GS reservoir pressures wi ll increase more in comparison to Class II ER during the injection
p hase of the GS project.

EPA continues to research and collect data on CO2 storage and containment. EPA is tracking operations at the DOE GS pilot projects and will review data on all aspects of those operations, from well construction and injection to long-te rm plume fate and transport and m onitoring of containment, as the data become available. In addition to the information cited in the preamble to the proposed rule, EPA
p ublished a Notice of Data Availability and Request for Comment on August 31, 2009 (74 FR 44802), in which the Agency described the results of research at three DOE partnership sites: the Escatawpa, Mississippi project; the Aneth Field project in Paradox Basin, Southeast Utah; and the Pump Canyon Site, New Mexico. Please also see the res earch described in the above response.

As part of its adaptive rulemaking approach, the Agency plans, every six years, to collect and review data on GS projects to determine whether the a ppropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

Other EPA Comment Codes and Descriptions: 1540 1.2.3.2 Climate change legislation Comment: Some personnel at the U.S. EPA and members of Congress often assume falsely that CCS or GS is commercially deployable now in all states based upon the success in the half dozen or perhaps as many as a dozen oil/gas production states. The development of a national viable and wo rkable CO2 capture and sequestration
p ermitting program is one of the key pr erequisites to the implementation of contemplated energy reform initiatives -ranging from state la ws that force reductions in CO2 to pending new Federal legislation to require a national cap (on CO2 emissions.) APPA’s comments ar e offered here on the UIC permitting system are valid regardless to whatever "carbon signal" there might be to reduce CO2 from power plants. Even if there is no new national law setting a carbon emissions limit, intensit y limit, carbon tax, or ne w generation requirement, states also have the ability to set state by state limits on 16 carbon dioxide emissions from power plants under separate state CO2 laws. APPA does not like
p atchwork quilt state by st ate regulatory approaches to reduce CO2 through different laws and regulations. It is entirely too s oon to know what Congress might do. At this time, we have no clue what Congress might do in the future to constrain CO2 that would motivate any part y to reduce CO2 from coal or natural gas plants. APPA’s comments are neutral as to the new legislative mechanism that would "constrain carbon". These technical, l ogistical, or cost issues are valid regardless of why utilities would want to inj ect CO2 under any carbon dioxide mitigation standard, reduction policy, or law.

Response: EPA acknowled g es that GS falls within the broade r context of CCS and the need for Commenter Name: Theresa Pugh Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23389regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordina ted with other Agency program of fices and across federal agencies (e.g., with the Department of Energy; United St ates Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcem ent, formerly the Minerals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applic ability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

EPA is also aware that states are currently in various stages of devel oping statutory frameworks, regulations, technica l guidance, and strategies for addressi ng CCS and GS. States can use multiple authorities beyond those afforded under the SDWA and UIC regulations, including laws and policies addressing surface access and land ri ghts, unitization of fields, pore space ownership, mineral rights, worker safety and emergency prepar edness, and maximization of state oil and gas resource exploitation. EPA plans to work closely with states and tribes as they develop Class VI primacy programs in this broader context. EPA adds that st ates may adopt more stringent stan dards for Class VI wells than the Federal requirements.

In a separate rulemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Gas (GHG) Reporting Program at 40 CFR Part 98 to add re porting requirements for facilities that conduct GS (subpart RR) and all other facilities that inject CO2 underground (subpart UU). For additional information, see the s ection of the final GS rule preamble enti tled, "How Does Mandatory Reporting of Greenhouse Gases (GHGs) Relate to This Rulema king?” and the GHG Repor ting Program rulemaking and docket.

Other EPA Comment Codes and Descriptions: 1420 1.2.1.1 Support the GS rulemaking; 2020 1.5.1 Support Class VI designation Comment: Overall Comments

ASDWA and its members appreci ate EPA’s efforts to devel op this rule under very limited time constraints and agree with EPA’s plan to create a new class of wells for carbon dioxide geol ogic sequestration sites. St ates believe that all appropriate steps need to be taken to en sure the effectiveness of Carbon Capture and Sequestration as a tool to mitigate greenhouse gas emissions, as well as avoid potential unintended consequences th at could have a negative impact on Underground Sources of Drinking Water (USD W). Additional research and data are needed to ensure that this rule is fu lly protective of all potential drinking
water sources.

Response: EPA acknowledges the comment and agrees that tailored requirements for Class VI wells are necessary to address the unique nature of injecting large volumes of CO2 and to ensure that USDWs are
p rotected from endangerment. The Class VI requirements ar e appropriate because of the unique nature and risks of CO2 in j ection for lon g -term stora g e (e. g ., lar g e in j ection volumes, lon g pro j ect duration, Commenter Name: James Taft Letter ID: 0172 Commenter Or g anization: Association of State Drinki ng Water Administrators (ASDWA) Comment ID: 23449and reservoir pressure conditions). The GS rule contains tailored requirements for the permitting, geologic site characterization, Ao R and corrective acti on, well construction, operation, mechanical integrity testing, monitori ng, well plugging, post-injection site care, and site closure of GS wells that directly address issues unique to the nature of large-scale CO2 injection for GS.

EPA agrees that continued research in all GS associat ed fields will be integr al to development of GS technology. EPA is aware of resear ch by other federal agencies, i ndustry, international parties, and academia related to GS, including projects that address many of the topics suggested by commenters. EPA published a Notice of Data Availability (NODA) and Request for Co mment on August 31, 2009 (74 FR 44802), in which the Agency described the results of research at three DOE partnership sites (in Escatawpa, Mississippi; the Aneth Field in Paradox Basin, southeast Utah; and the Pump Canyon Site, N ew Mexico). In the NODA and Request for Co mment, EPA also described two studies by the Lawrence Berkeley National Labor atory on the potential effects of CO2 injection on ground water and surrounding formations to determine the potential fo r impacts on USDWs and human health in the event that a GS project is not properl y sited, operated, or managed.

To protect USDWs from endangerment and meet the potentially fast pace of GS deployment, EPA is using an adaptive approach to regulating CO2 injection for GS. The Agency plans to, every six years, collect and review data on GS projects to determ ine whether the appropria te amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or nece ssary. An adaptive approach will allow regulatory development to
p roceed in time to meet the current and future demands for Class VI permits, while EPA continues to gather data from pilot projects and othe r research as it becomes available.

Comment: Guiding Principals

Addressing climate change wi ll require a full portfolio of options for reducing greenhouse gas emissions. Dominion believes that carbon capture and storage (CCS) is an essential component of any future climate change mitigation policy and, accordingly, commends EPA for in itiating the rulemaking process.

Dominion supports the development of clear , flexible, scalable and appropriate regulations that will faci litate investment and deve lopment of CCS technology while assuring appropriate protections ag ainst adverse impact s to underground sources of drinking water (USDW). Domini on feels that the proposed regulations achieve these goals in many respects.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. EPA recognizes the impor tance of providing clear, flexible, scalable, and appropriate regulations, and beli eves that the GS regulation will provide certainty to industry and the public by providing consistency in requirements across the U.S. and transparency about what requirements apply to owners or operators.

Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket. Commenter Name: Pamela Faggert Letter ID: 0175 Commenter Or g anization: Dominion Comment ID: 23513Other EPA Comment Codes and Descriptions: 1420 1.2.1.1 Support the GS rulemaking Comment: Executive Summary

Addressing climate change con cerns requires a full commit ment to development and commercial deployment of carbon capture and storage (CCS) technologies. EEI thus supports the development of clear, flexible and appropriately tailored regulatory regimes that will facilitate development of and investment in CCS technology and projects while protecting ag ainst potential environmental risks. We applaud the Agency for taking this cr ucial first step toward establishing such a regime for geological sequestrati on (GS). Recognizing the significance of EPA‘s initiative in proposing regulations for the injection and storage of carbon dioxide (CO2) under the Safe Dri nking Water Act‘s (SDWA) Underground Injection Control (UIC) pr ogram, EEI appreciates the opportunity to provide input into the process and to share our suggestions for changes to the proposed rule. Incorporation of our comments into the final rule will serve to promote the dual goals of promoting the comm ercialization of CCS technology and
p reventing potentially undesirable impa cts to drinking water resources.

Response: EPA believes that the creation of a new in jection well class (V I) under the existing UIC Program is necessary to enable the use of GS as a climate change mitigation technology in a manner that
p rotects USDWs from endangerment. EPA agrees th at the UIC Program, under the authority of the SDWA, provides a strong framework for regulating injection of CO2 for GS and adds that the GS regulation tailors the UIC requirements to address the unique issues associated with large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurit ies in captured CO2, and its mobili ty within subsurface geologic formations.

Other EPA Comment Codes and Descriptions: 1420 1.2.1.1 Support the GS rulemaking Comment: I. General Principles Applicable To EPA's GS Regulatory Effort

As we noted in our prior comments, addre ssing climate change concerns requires a full commitment to development and comm ercial deployment of carbon capture and storage (CCS) technologies. To put the n eed for this commitment in context, consider that electricity generation is responsible for 34 percent of greenhouse gas (GHG) emissions and 40 percent of CO 2 in the U.S. The Energy Information Administration projects ne t electric demand will in crease 30 percent by 2030, even after taking into account energy-efficiency improvements. New and replacement power plant capacity to meet this increased demand is projected to total 150,000 megaWatts. Coal is one of the primary sources of baseload generation in the U.S. and will continue to be an important fuel for generating electricity through 2030 because it is comparatively affordable and abundant in this country. Given this backdrop, the poten tial environmental benefits of CCS - in terms of reduced or avoided CO2 emis sions - are substantial. Consequently, EEI and our members see CCS as a critical element in the full portfolio of options needed not only to reduce CO2 emi ssions, but also to ensure continued affordable and reliable electri c service to customers throu g hout the nation. Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23549

Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23561EEI thus supports the development of clear, flexible and approp riately tailored regulatory regimes that will facilitate development of and investment in CCS technology and projects while protecting ag ainst potential environmental risks. We applaud the Agency for taking this cr ucial first step toward establishing such a regime for GS. Recognizing the si gnificance of EPA's initiative in
p roposing regulations for the injection and storage of CO2 under SDWA's UIC
p rogram, EEI appreciates the opportunity to provide input into the process and to share our suggestions for changes to the proposed rules. Incorporation of our comments into the final rules will serve to promote the dual goals of
p romoting the commercialization of CCS technology and preventing potentially undesirable impacts to dri nking water resources.

Response: EPA believes that the creation of a new in jection well class (V I) under the existing UIC Program is necessary to enable the use of GS as a climate change mitigation technology in a manner that
p rotects USDWs from endangerment. EPA agrees th at the UIC Program, under the authority of the SDWA, provides a strong framework for regulating injection of CO2 for GS and adds that the GS regulation tailors the UIC requirements to address the unique issues associated with large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurit ies in captured CO2, and its mobili ty within subsurface geologic formations.

EPA agrees that the implem entation of the GS rule in a manner that ensures protection of USDWs from endangerment is important to esta blishing a foundation for further adva nces in the field of CO2 GS. EPA acknowledges the need for regulatory certainty: the final GS requirements provide a level of certainty by setting forth unique requirements for GS. These require ments include: the tailored AoR delineation process (per §146.84), the types of moni toring appropriate to GS projects (per §146.90), and the post-injection site care process (per §146.93).

While EPA agrees with commenters that a stable, predictable, nationally consistent, and workable regulatory framework is important, EP A stresses that the focus of the GS rule is to ensure that, where GS is deployed, it is conducted in a manner that protects USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 1200 1.1 General comments about the rulemaking Comment: EEI's views are guided by several general principles applicable to any federal legislative or regulatory effort on CCS, which are described below and discussed more fully in the context of specific comments:

1. Promotion of CCS. As EPA acknowledges in the preamble, CCS is a key climate change mitigation technology, and the proposed rules are intended to support its development.[FN2] Likewise, any EPA regulatory regime re lated to CCS developed under the authority of SDWA (or any other statute) should be designed to facilitate, and not unduly hinder, the succ essful commercial-scale deployment of CCS. The potential environmental benefi ts of such deployment in terms of reduced or avoided GHG emissions should be wei ghed against potential requirements that might delay or compromi se the ability to achieve commercialscale CCS. Issues the Agency should consider in connection with this principle include: Commenter Name: Quinlan J. Shea Letter ID: 0177 Commenter Or g anization: Edison Electric Institute Comment ID: 23562[FN2] 73 Fed. Reg. 43495, col.1.

Response: EPA clarifies that the intent of the GS rule is not to promote or en courage the use of GS; rather, its purpose is to ensure consistency in permitting undergr ound injection of CO2 at GS operations across the United States and provi de requirements to prevent endange rment of USDWs in anticipation o f the eventual use of GS to reduce CO2 emissions. Plea se see the remainder of EPA's responses to this comment for further details. For additional informat ion on EPA's final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 Comment: If atmospheric emissions of CO2 are to be controlled, CCS is the only tool now on the horizon that may be capable of a ddressing in a major way and within a mid-term timeframe, the very large quantities of CO2 emissions from fossil-fuel using facilities in the United Stat es. However, CCS still requires the definition of a stable and rational legal and regulatory regime before it can be widely deployed. EPA has clear regulatory au thority over the injection of wastes and other substances into below-surface wells through the UIC program. The UIC
p rogram was created by Congress under the Safe Drinking Water Act ("SDWA") over 30 years ago, without consideration of pot ential interaction with policies to address climate change, for the protec tion of underground sources of drinking water ("USDW). The Agency now proposes to use this framework to regulate belowground CO2 injection activities, an appli cation not contemplated at the time SDWA was drafted. Rules for geologic sequestration ("GS") of CO2 are timely and would be needed even if CCS is not depl oyed as quickly as many predict. While many projects are under development, ma ny observers are operating under the assumption that it will be a decade or mo re before there can be wide deployment of CCS.[FN3] The future of CC S is and will be at a critical juncture for some years. The CCS Alliance seeks, through its comm ents, to help ensure that these regulatory activities promot e well designed and implemented CCS projects with sound risk management practices, and do not preclude the responsible, cost effective commercial-scale sequestration of CO2.

[FN3] See, e.g., "EPRI Summer Seminar and Energy Technology Assessment Center (ETAC) Studies," presentation of Hank Courtright, Senior Vice President, Electric Power Research Institute. October 22. 2008.

Response: EPA believes that the creation of a new in jection well class (V I) under the existing UIC Program is necessary to enable the use of GS as a climate change mitigation technology in a manner that
p rotects USDWs from endangerment. EPA believes that the UIC Program, under the authority of the SDWA, provides a strong framework for regulating injection of CO2 for GS and adds that the GS regulation tailors the UIC requirements to address the unique issues associated with large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurit ies in captured CO2, and its mobili ty within subsurface geologic formations.

EPA a g rees that the implementation of the GS rule in a manner that ensures pr otection of USDWs from Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23796endangerment is important to esta blishing a foundation for further adva nces in the field of CO2 GS. EPA acknowledges the need for regulatory certainty: the final GS requirements provide a level of certainty by setting forth unique requirements for GS. These require ments include: the tailored AoR delineation process at §146.84, the types of monito ring appropriate to GS projects §146.90, and the postinjection site care process §146.93.

Comment: Geologic sequestration holds promise as a key component in the promotion of cleaner coal technologies. As a coal produci ng state, we are especially interested in technologies that will se cure the industry’s future in the face of the challenges associated with reducing greenhouse gas emissions, thereby mitigating the impacts from global warming.

Our commitment to greenhouse gas reductions is reflected in Colorado’s Climate Action Plan which calls for reducing greenhouse gas emissions by 20% from 2005 levels by 2020. We cannot full y realize this goal wi thout cleaner coal technologies. But emerging solutions, such as geologic sequestration, must be technologically and environmentally sound and supported by a viable and efficient regulatory framework.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions.

Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: As EPA has correctly recognized, it is cr itical that any UIC program regulation addressing GS be designed to achieve two goals. First - obviously - such a rule should ensure that CO2 injection is conducted in a manner that is protective of human health and the environment. Se cond, such a rule should effectively facilitate the development of GS as a means for greenhouse gas (GHG) mitigation. EPA’s rulemaking effort will prove successful only to the extent that both of these goals are achieved.

Fortunately, there is abundant evidence that CO2 injection can be accomplished in a manner that is protectiv e of human health and the environment. Indeed there has been a long history of successful in jection well operation in the United States, and multiple studies have conf irmed that the UIC program has been remarkably effective in ensuring protection of human health and the environment. While GS projects are likely to be large in scale, it is important to recognize that the injection of CO2 is nothing new. To the contrary, CO2 has been injected for purposes of enhanced oil and gas rec overy (EOR/EGR) for more than thirtyfive y ears, and the UIC pro g ram alread y re g ulates more than thirteen thousand Commenter Name: Ginn y Brannon Letter ID: 0182 Commenter Or g anization: Colorado Department of Public Health and Environment Comment ID: 23752

Commenter Name: Robert F. Van Voorhees Letter ID: 0190 Commenter Or g anization: Carbon Sequestration Council Comment ID: 24316CO2 injection wells that have successfully injected more than 600 million tons of CO2. Accordingly, there is a vast body of experience demonstrating that CO2 injection can be conducted without adve rse impacts on human health and the environment.

Response: EPA acknowledges the comment. Pl ease see the remainder of EPA’ s responses to this letter for further details. For additional information on EP A’s final regulatory approa ch, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1420 1.2.1.1 Support the GS rulemaking Comment: of energy sources including renewable energy. Southern Company has already begun a CO2 injection project at a deep sa line-filled geologic formation in Mississippi as part of the Southeast Ca rbon Sequestration Regional Partnership. We believe that carbon capture and storage ("CCS") is critical to the likely federal goal of reducing greenhouse gas emi ssions and to the implementation of a number of federal and state energy reform initiatives; we are proud of our efforts to help bring this important t echnology towards commerci al viability and generally support EPA's effo rts in this rulemaking.

Carbon capture and storage has the potential to lead to substantial environmental benefits in terms of avoided CO2 emissions. Therefore, a workable CCS program, including a regulatory fram ework for long-term carbon dioxide sequestration as anticipated by this rulemaking, is an es sential element in the full portfolio of options needed to ensure continued affordable and reliable electric service to customers throughout th e United States while reducing CO2

Response: EPA believes that the creation of a new in jection well class (V I) under the existing UIC Program is necessary to enable the use of GS as a climate change mitigation technology in a manner that
p rotects USDWs from endangerment. EPA agrees th at the UIC Program, under the authority of the SDWA, provides a strong framework for regulating injection of CO2 for GS and adds that the GS regulation tailors the UIC requirements to address the unique issues associated with large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurit ies in captured CO2, and its mobili ty within subsurface geologic formations.

Comment: warming. With Eastman’s long-term commitment to gasification technology the company has a vested interest in the geologic storage of CO2 that is important for the continued viability of gasificatio n facilities. Eastman Chemical Company supports the following comments on the proposed rule generated by the Gasification Technologies Council.

Gasfication is an important technology for the convers ion of coal, biomass,
p etroleum coke, municipal solid waste (MSW) and other carbonaceous feedstocks to
p ower, chemicals, fertilizers and cleaner fuels. With gasification, CO2 can be captured usin g commerciall y available technolo g ies. Due to its inherent carbon Commenter Name: Chris M. Hobson Letter ID: 0201 Commenter Or g anization: Southern Compan y Comment ID: 22153

Commenter Name: Richard Guinn Letter ID: 0210 Commenter Or g anization: Eastman Chemical Compan y Comment ID: 22690capture capability, gasification can serv e a major role in Carbon Capture and Storage (CCS) projects. GTC’s interest in EPA’s proposed regulation derives from the importance of CCS to achieving future goals of CO2 emissions reduction while using secure and indigenous resources to meet our growing national need for chemicals, fertilizers, liquid fuels, hydrogen, and electricity.

Response: EPA clarifies that GHG emissions reductions and the use of integrated gasification combined cycle technologies are outside the scope of the UIC GS rulemaking. Th e purpose of the GS rule is to ensure that, where GS is deployed, the projects are permitted sited, constructed, operated, and closed in a manner that protects USDWs from endangerment. Th e requirements apply to owners or operators of injection wells used to inject CO2 for long-term storage.

Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: As we studied the feasibility of developi ng an IGCC project with CCS, we learned a great deal about geologic storage of CO2. We learned th at geologic storage is currently one of the most important means by which power companies can reduce CO2 emissions while still producing reliab le and affordable energy from coal. International studies as well as studies here in this country attest to the importance of geologic storage of CO2 in any strategy to reduce increasing carbon concentrations in the atmosphe re. The development of a rational regulatory framework to addre ss geologic storage of CO2 is essential in order to balance the nation's need for energy security, through increased use of domestic energy resources, with concerns over global clim ate change.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1410 1.2.1 Comments in support of EPA/rulemaking Comment: As an initial matter, we applaud EPA’ s significant efforts to include and encourage broad stakeholder participation both before and after publication of the Proposed Rule. Furthermore, it is ev ident from the Proposed Rule that EPA considered and incorporated many of the stakeholders’ comments from the public workshops. Accordingly, EPA adopted a fram ework that is intended to encourage the deployment of carbon capture and sequestration or storage ("CCS") in a manner that is protective of underground sources of dr inking water ("USDWs"). There is growing consensus among scientists, environmental groups and members of government that CCS will play a critic al role in addressing greenhouse gas emissions.

Response: EPA agrees that input of and participation by a wide spectrum of stakeholders is a vital component of successful rulemakin g . The A g enc y appreciates the de g ree of cooperation, participation, Commenter Name: Olon Plun k Letter ID: 0217 Commenter Or g anization: Xcel Ener gy , Inc. Comment ID: 21549

Commenter Name: Tiffan y Rau Letter ID: 0224 Commenter Or g anization: H y dro g en Ener gy International Comment ID: 21646and active dialogue between the EPA and stakeholders and will continue to work with stakeholders and experts as it implements the GS rule.

Comment: The comments herein are founded on knowledge and experience gained through decades of industry operations, and are in tended to provide constructive input on the Proposed Rule. HEI’s comments are based upon two important and mutuallyachievable goals: (1) protecting USDWs; and (2) adopting regulations that are reasonable, cost-effective and facilitate geologic sequestration of CO2. HEI concurs with EPA’s conclusion that CCS presents a "key climate change mitigation technology." (73 Fed. Reg. at 43495.)

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: workshops. Accordingly, EPA adopted a framework that is intended to encourage the deployment of carbon capture and sequestration or storage ("CCS") in a manner that is protective of underground sources of dr inking water ("USDWs"). There is growing consensus among scientists, environmental groups and members of government that CCS will play a critic al role in addressing greenhouse gas emissions.

The comments herein are founded on knowledge and experience gained through decades of industry operations, and are in tended to provide constructive input on the Proposed Rule. BP’s comments are based upon two important and mutuallyachievable goals: (1) protecting USDWs; and (2) adopting regulations that are reasonable, cost-effective and facilitate geologic sequestration of CO2. BP concurs with EPA’s conclusion that CCS presents a "key climate change mitigation technology." (73 Fed. Reg. at 43495.)

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: capacity--enough to power nearly 20 million homes. NRG believes that emissions of GHGs from power generation and ot her sectors must be reduced, both domestically and internationally, to suc cessfully address climate change, and that commercially attractive, safe and environmentally secure carbon capture and sequestration will be critical for that success. Headquartered in Princeton, NJ, N RG is a member of the U.S. Climate Action Partnership (USCAP), a group of business and environmental organizations calling for mandatory legislation to reduce g reenhouse g as emissions. Commenter Name: Tiffany Rau Letter ID: 0224 Commenter Or g anization: H y dro g en Ener gy International Comment ID: 21647

Commenter Name: Brian Williams Letter ID: 0225 Commenter Or g anization: BP Alternative Energy North America, Inc. (BP) Comment ID: 21712

Commenter Name: Steven B. Corneli Letter ID: 0234 Commenter Or g anization: NRG Ener gy , Inc. Comment ID: 23158Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: electricity generation facilities. Cu rrently, Montana-Dakota generates a majority of its electricity through fossil -fired power plants. Therefore, the
p roposed rule, in providing additional certainty in capturing and sequestering CO2, is expected to support Montana-Da kota's continued utilization of the region's abundant fossil fuel resources in order to continue generating affordable electricity fo r its customers. Montana-Dakota believes it is important to proceed with development of CO2 GS projects while preventing
p otentially undesirable impacts to drinking water resources.

Response: EPA acknowledges the comment. Pl ease see the remainder of EPA’ s responses to this letter for further details. For additional information on EP A’s final regulatory approa ch, please see the final rule and preamble as well as the rulemaking docket.

Comment: Among WEST Associates' membership, coal-fired generation constitutes a significant proportion of electrical ge neration resources for the western states, and the nation as a whole relies on more than 50% of its generation from coal-fired power plants. Demographic growth in the west ern states has been, and likely will continue to be, greater than the rest of the U.S.; as a result, coal generation and the potential need to ab ate it’s growing CO2 emissions will require effective options such as GS. Cl early, as the nation em barks on programs to reduce greenhouse gas (GHG) emissions to achieve it's climate change goals, the option of carbon sequestration through under-ground injection wells must be a significant part of the CO2 emissions abatement program for fossil fuel generation. In its preamble to this rule making, EPA notes that the UIC Program and GS are "one of a portfolio of opti ons" for successful abatement of CO2 emissions to the atmosphere.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. Please see the remai nder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: WEST generally supports a well-designed and cost-effective na tional program for CO2 abatement, and believes that some of the features of th e Lieberman-Warner Bill (S.2191) present a fair start for negotiating a workable program in Con g ress. Indeed, EPA estimated in its revi ew of S.2191 that Carbon Capture and Commenter Name: Abbie Krebsbach Letter ID: 0235 Commenter Or g anization: Montana-Dakota Utilities Co. Comment ID: 23176

Commenter Name: Kevin Wanttaja Letter ID: 0248 Commenter Or g anization: Western Ener gy Suppl y and Transmission Associates Comment ID: 22238

Commenter Name: Kevin Wantta j a Letter ID: 0248 Commenter Or g anization: Western Ener gy Suppl y and Transmission Associates Comment ID: 22239Sequestration (CCS) technology could account for about 30% of CO2 emissions reductions sought by year 2050 under that bi ll. Notably, the 11 western states where WEST members reside and produ ce electricity, the regional geology, geography and its demographics in the vast spaces of the West may provide unique sequestration opportunities in general proximity to abundant coal supplies and coal powered generating plants. Na tional legislation and regulatory developments such as this one on UIC of CO2 for GS, should remove legal and institutional barriers that prevent th e development and use of carbon capture and storage/sequestration technologies. That is, the design of a UIC/GS regulatory program should promote efficient and simple regulation without redundancies with other regulations, ye t maximize protection of underground sources of drinking water ("USDW"), and the public health and safety above ground.

Response: EPA acknowledges that the issue of GS fall s within the broader context of CCS and acknowledges that regulatory clarit y is essential for enabling GS to move forward in a manner that
p rotects human health and the environment. The Agency is working to identify areas related to GS that could be addressed under other statutes to ensure that GS is conducted in a manne r that is protective of human health and the environment. Additionally, the Agency is and will continue to coordinate internally and with other Federal agencies involved in GS and CCS, including the Bureau of Ocean Energy Management, Regulati on and Enforcement, Bur eau of Land Management, and the United States Geological Survey, to promote consistency in existing and future GS initiatives.

Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: The Roundtable strongly suppor ts the aggressive research and development efforts underway to facilitate commercial-scale CO2 capture and sequestration ("CCS")
p rojects. We also believe that expansi on of enhanced oil recovery ("EOR")
p resent a meaningful opportunity to utilize CO2 in a way that is beneficial to the global environment and both our nati on’s economy and its energy security.

Response: EPA clarifies that injection of CO2 for the pur poses of enhanced oil and gas recovery will continue to be permitted under the Class II program, as long as any oil or gas production is occurring. The UIC GS requirements will apply to wells used for the purpose of long-term GS. The intent of the Class VI regulations is not to prom ote or encourage the use of GS, but , instead to ensure protection of USDWs where GS technologies are deployed.

For additional information on EPA’s approach to well s that are transitioning fr om ER to GS, see the discussion of Class II wells under “H ow Does This Rule Affect Exis ting Injection Well s Under the UIC Program?” in the preamble to the final GS rule.

Other EPA Comment Codes and Descriptions: 1350 1.1.3.3 Comments on the need for GS technolo gy Commenter Name: James T. Sims Letter ID: 0249 Commenter Or g anization: Western Business Roundtable Comment ID: 22254

Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22270Comment: While it is not a "silver bullet", one important tool is the geologic sequestration (GS) of CO2 at properly sele cted and properly regulated sites. Our Environmental NGO Group does not necessari ly have a common view concerning the magnitude of the long-term role of GS in combating climate change, but we are united in recognizing that a transition away from fossil fuels will take time and that GS is likely to be an importa nt part of the near- to medium-term solution. Fortunately, capturing CO2 and permanently sequestering it in certain types of well-selected and well-managed geologic formations is a technology that is ready to begin deployment today. While GS projects can be permitted today under the Safe Drinking Water Act’s (SDWA) UIC program (in fact a number of
p rojects have already been permitted under existing we ll classes), the rules that currently apply to such projec ts were not designe d with geologic sequestration in mind. Thus, the importance of this rulemaking is not that it is needed in order for GS projects to recei ve permits; rather, the rulemaking is important because it can assure that GS projects are regulated under rules that are specifically designed to require GS projects to be done safely and effectively without endangering underground sources of drinking water (USDWs) or, as discussed below, resulting in a risk of release to the atmosphere. For that reason, it is essential that EPA promulgate final ru les for GS in a timely manner that are sufficient to protect USDWs.

Response: EPA agrees that GS is one technology in a portfolio of options, including solar, wind, biomass, and geothermal, that c ould be deployed to reduce CO2 em issions; however these technologies are outside the scope of the UIC GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed to address climate change, projects are perm itted sited, constructed, operated, and closed in a manner that avoids releases of CO2 into USDWs.

Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: The NAM supports development and deployment of advanced, energy efficient and zero-and-low-Greenhouse Gas (G HG) emission and sequestratio n technology as part of a long-term strategy to reduce GHG emissions in the U.S. economy. Many members of the NAM have a direct inte rest in removing impediments to the development of CCS technology in order to increase its commercial viability. Pursuant to issues raised specifically by the proposal, the NAM believes that CCS can be developed in a manner that does not undermine the safety of underground sources of drinking water.

Response: EPA agrees that large-scale GS can be done safely. The GS regulation builds upon the longstanding protective framew ork of the UIC program, which has been regulating the injection of billions of gallons of liquids for decades. The GS regulation enhances this existing framework with requirements for GS wells that are tailored to the unique nature of large-scale GS of CO2. These additional protective requirements include more extensive geologic testi ng, detailed computational modeling of the AoR and
p eriodic re-evaluations, detailed requirements for monitoring and trac king the CO2 plume and pressure front, and extended post-injecti on monitoring and site care. Commenter Name: Keith McCo y Letter ID: 0258 Commenter Or g anization: National Associati on of Manufacturers Comment ID: 22373For additional information on EPA’s final regulatory appr oach, please see the final rule and preamble as well as the rulemaking docket.

Comment: Geological sequestration of CO2 is, in sum, one of the important tools available for stabilizing CO2 levels in the atmosphere, and Basin Electric/DGC's Weyburn
p roject is currently the largest carbon sequestration project in the world demonstrating the feasibility of such ca pture and storage. Whatever steps are taken either legislatively or through ru lemaking to regulate CO2 and other greenhouse gases (GHGs) must allow CC S technology and other carbon and GHG control technologies to be developed, and must allow a reasonable time frame to do so.

II. Importance of Developi ng Reasonable Regulations

The energy needs of the United States are dependent upon carbon producing fuels. The development of reasonable regulations , including reasonable regulations for carbon dioxide capture and sequestration (CCS ), thus is crucial for CCS is to fulfill its potential as one of the important ways to mitigate greenhouse gas impacts. "While other climat e mitigation options exist-such as energy efficiency improvements, a switch to less carbon-in tensive fuels, nuclear power, and renewable energy sources-CCS is considered by many to be a crucial component of any U.S. approach or strategy for a ddressing the climate change problem,
p articularly given the United States' curr ent reliance on coal for almost half of its electricity production." [FN8]

The use of carbon dioxide for enhanced oil recovery (EOR) is also generally recognized as an important intermediate step in developing EOR, because the knowledge and technology is already there to begin to use it. "The injection of CO2 in deep geological formations involve s many of the same technologies that have been developed in the oil and gas exploration and production industry. Well-drilling technology, injection technol ogy, computer simulation of storage reservoir dynamics and moni toring methods from existing applications are being developed further for design and operati on of geological storage." [FN9]

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in these technologies is outside the scope of the UIC GS rulemaking.

EPA clarifies that the intent of the Class VI regulati on is not to promote or encourage the use of GS, but, instead to ensure protection of USDWs where GS technol ogies are deployed. Pleas e see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket. Commenter Name: Claire Olson Letter ID: 0260 Commenter Or g anization: Basin Electric Power Cooperative Comment ID: 22385

Commenter Name: Michael Moore Letter ID: 0265 Commenter Or g anization: North American Carbon Capture & Storage Association (NACCSA) Comment ID: 22850Comment: II. General Principles Applicable To EPA's GS Regulatory Effort

As legislative and regulatory efforts to a ddress climate change accelerate, it is critically important that policymakers follow EPA's lead by continuing to recognize the central role that CCS can play as a mitigation tool. As noted in the Preamble to EPA's proposed rule, CCS holds the promise of storing large volumes of carbon dioxide in geologic formations such as deep saline formations, depleting and depleted oil & natural gas reservoi rs, unmineable coal seams and similar geologic structures. Because CCS has the potenti al to be applied in a wide range of fossil fuel production processes, NACCSA be lieves that CCS should be recognized as an emissions mitigation measure under a ny climate regime. A dditionally, NACCSA members view carbon dioxide as a central component in the enhanced recovery of oil and natural gas and recognize that it is capable of being responsibly stored as
p art of this process.

Recognizing the significance of the init iative displayed by EPA in proposing regulations for injection and storage of CO2 carbon dioxide under the Safe Drinking Water Act's UIC progr am, NACCSA appreciates the opportunity to provide input on which aspects of the proposed rules are favorable, and for which aspects of the proposed rules EPA should consider possible changes, in light of the rulemaking's dual goals of improving th e chances of achieving commercial viability for CCS while also preventing potentially undesirable impacts to drinking water resources. NA CCSA's general areas of focus in this discussion include siting and secondary containment; monitoring/use of tracers; closure and post-injection site care; financial assurance; grandf athering; state primacy; and potential issues arising under other e nvironmental laws. Comments on specific aspects of the Agency's proposed rules wi thin these general focus areas are set forth below.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional inform ation on EPA’s final regulat ory approach (including information on siting and cont ainment, monitoring and use of tracers, site closur e and post-injection site care, financial assurance, primacy, transitioning existing wells into Class VI wells, and potential issues arising under other environmental laws), please see the final rule and preamble as well as the rulemaking docket.

Comment: First, I'd like to provide some contex t for our comments. Oil and natural gas and coal provide approximately 85 perc ent of the world's energy. The power
p lants, vehicles, homes, businesses and f actories that use these fuels produce more than 25 billion tons of carbon di oxide emissions annually. While no single technology is sufficient to mitigate th ese emissions, capturi ng CO2 and storing it deep underground in formations could play an important role.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket. Commenter Name: Michele Schoeppe r Letter ID: 0503 Commenter Or g anization: American Petroleum Institute Comment ID: 21170Comment: CCS is one of the essential technologies that could help to ensure that we can continue to produce the clea n energy society demands.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: My perspective is this, I believe ge ologic sequestration is essential and urgently needed, especially because co al is a major contributor to global climate change both in the United States and all around the world. And if coal is to be used it must be used on the basis of sequestration of 100 percent of the CO2.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in these technologies is outside the scope of the UIC GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, proj ects are permitted, sited, constructed, operated, and closed in a manner that protects USDWs from endangerment. For a dditional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: I'd like to start out by agreeing with a couple of comments made previously. First, agree with the Sierra Club, that CC S is not a silver bullet, we believe it's a critical technology in the fight ag ainst climate change , but it's not a silver bullet by any means.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: Geologic sequestration holds promise as a key component in the promotion of
p remier coal technologies. As a coal producing state in Colorado, we are especially interested in technologies that will secure the industry's future in the face of the challenges associated wi th reducing greenhouse gas emissions and thereby mitigating the impa cts from global warming.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deplo y ed to reduce CO2 emissions. However, the use of and investment in these Commenter Name: Michele Schoeppe r Letter ID: 0503 Commenter Or g anization: American Petroleum Institute Comment ID: 21180

Commenter Name: Mark Singe r Letter ID: 0504 Commenter Or g anization: Green America Pro j ect, LLC Comment ID: 21241

Commenter Name: Scott Anderson Letter ID: 0510 Commenter Or g anization: Environmental Defense Fun d Comment ID: 21215

Commenter Name: Ginn y Brannon Letter ID: 0521 Commenter Or g anization: Colorado Department of Public Health and Environments Comment ID: 21445technologies is outside the scope of the UIC GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, proj ects are permitted, sited, constructed, operated, and closed in a manner that protects USDWs from endangerment. For a dditional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: First I would like to provide some cont ext for our comments. Oil, natural gas and coal provide approximately 85% of the world's energy. The power plants, vehicles, homes, businesses and factories th at use these fuels produce more than twenty five billion tons of CO2 emis sions annually. While no single technology is sufficient to mitigate human CO2 emis sions, capturing CO2 a nd storing it in deep underground format ions could play an important role.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: the innovations that could improve both well security and performance. CCS is one of the essential technolog ies that could help to ensure that we can continue to produce clean energy society demands.

Response: EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulator y approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: I applaud the EPA for proposing these regul ations. CCS holds significant promise to manage carbon emissi ons and should be part of any climate change regime. CCS is also essential to enhanced oil and gas recovery which we believe can be combined with permanent storage.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in these technologies is outside the scope of the UIC GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, proj ects are permitted, sited, constructed, operated, and closed in a manner that protec ts USDWs from endangerment.

EPA clarifies that injection of CO2 for the purposes of enhanced oil and gas recovery will continue to be
p ermitted under the Class II program , as long as any oil or gas pr oduction is occurring. The UIC GS requirements will apply to wells used for the purpose of long-term GS. For additional information on EPA’s approach to wells that are transitioning from ER to GS, see the discussi on of Class II wells under “How Does This Rule Affect Existin g In j ection Wells Under the UIC Pro g ram?” in the preamble to the Commenter Name: Steve Crookshan k Letter ID: 0523 Commenter Or g anization: American Petroleum Institute (API) Comment ID: 21353

Commenter Name: Steve Crookshan k Letter ID: 0523 Commenter Or g anization: American Petroleum Institute (API) Comment ID: 21363

Commenter Name: Mike Moore Letter ID: 0532 Commenter Or g anization: North American Carbon Capture and Storage Association (NACCSA) Comment ID: 21365final GS rule.

Comment: We believe that the problem of economics and problem with policy can put CCS in context and give it the role that it needs. Nonetheless, we do not believe that we can do away with this if we are goi ng to meet emission reduction targets in time, so this is what we think is an ab solutely necessary part of the mitigation
p ortfolio. We would like to see things happen otherwise; I think technically it is feasible. The way that some of th e developing economies are growing these days and the way the political situation in the U.S. is heading, means that we wanted to use CCS as well.

Having spent a good few years studying this and we took great care in being diligent, as an environmen tal group the idea of inject ing large volumes of CO2 underground that is not the most appealing at first. Nonetheless, the more we studied this, the more convinc ed we become that if regulated and performed well, it can be very safe and effective. And I stress the words, can be.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. EPA clarifies that the purpose of the UIC GS regulation is to ensure that GS is conducted in a manner that protects US DWs from endangerment.

EPA believes that large scale GS can be done sa fely. The GS regulation builds upon the long-standing
p rotective framework of the UIC program, which has been regulating the injection of billions of gallons of liquids for decades. The GS regulation enhances this existing framework with requirements for GS wells that are tailored to the unique nature of large scale GS of CO2. These additional protective requirements include more extensive geologic testi ng, detailed computational modeling of the AoR and
p eriodic re-evaluations, detailed requirements for monitoring and trac king the CO2 plume and pressure front, and extended post-injecti on monitoring and site care.

Comment: I do not agree with the assertion that CCS is unproven, untried or untested. I think there was a good body of experience in related context that gives us reason to believe that CCS is safe and effective. EOR as one of those examples, I do not claim that EOR is tantamount to CCS. There are key differences. N onetheless, there are fields that inject very large vol umes of CO2 annually and in the U.S. and elsewhere. Some of these injections are well above the amount of CO2 that would be injected annually by a large qualified power plant.

We do not have the monitori ng provisions in place that we would have with a standard sequestration project. Nonetheless, there are studies that are almost completed that show, and these are going to be published I think within the next few weeks or few months by the University of Texas, that show that there is indeed no real contamination issue at some of the major UI projects and fields. Even though the objective is not to keep the CO2 down for hundreds of millions of y ears or thousands of y ears, nonetheless we have in j ected ver y lar g e volumes Commenter Name: Geor g e Peridas Letter ID: 0534 Commenter Or g anization: Natural Resources Defense Council (NRDC) Comment ID: 21451

Commenter Name: Geor g e Peridas Letter ID: 0534 Commenter Or g anization: Natural Resources Defense Council (NRDC) Comment ID: 21452of CO2 and the regulatory experience in Class II has shown that we have not come across any major contamination issues.

The other I think major and striking example of CCS which is often overlooked is nature itself. CO2, methane and even H2S, hydrogen sulfide are occurring naturally in the subsurface. The fields that the industry has actually mined contained fairly pure CO2. These large volu me fields, they have been there and they are testament that CO2 can be stor ed by nature in the subsurface for a very, very long time and very effectively.

Oil fields and gas fields and also the deep saline formations also show nature's ability to retain those fluids, so I w ould urge a close study and consideration of what nature has done already. Just putting a label on a new technique and calling it sequestration does not necessarily mean that it has not been done before.

Response: EPA clarifies that the purpose of the UIC GS regulation is to ensure that GS is conducted in a manner that protects USDWs from endangerment. EPA agrees that large scale GS can be done safely. The GS regulation builds upon the long-standing protective framework of the UIC program, which has been regulating the injection of bi llions of gallons of liquids for decades. The GS regulation enhances this existing framework with requirements for GS wells that are ta ilored to the unique nature of large scale GS of CO2. These additional protective requirements include more extensive geologic testing, detailed computational modeling of the AoR and periodic re-evaluat ions, detailed requirements for monitoring and tracking the CO2 pl ume and pressure front, and exte nded post-injection monitoring and site care.

Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: First we have learned that carbon sequest ration is currently one of the most important means by which power companie s can reduce carbon di oxide emissions while still producing reliable and affordable energy from coal.

International studies as well as studies here in this country attest to the importance of geologic sequestration of carbon dioxide in any strategy to reducing increasing carbon concentr ations in the atmosphere.

Second, working with respected geo-techni cal and reservoir consultants to DOE sequestration partnerships and a world re nowned national lab, we learned that geologic storage of CO2 is not only feasible, but actually happening successfully in a number of places around the world. We also discovered there are viable and even favorable sites to sequester large quantities of CO2 right here in Colorado.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deplo y ed to reduce CO2 emissions. However, the use of and investment in these Commenter Name: Olon Plun k Letter ID: 0536 Commenter Or g anization: Xcel Ener gy Comment ID: 21375technologies is outside the scope of the UIC GS rulemaking.

EPA agrees that large scale GS can be done safely. The GS re gulation builds upon the long-standing
p rotective framework of the UIC program, which has been regulating the injection of billions of gallons of liquids for decades. The GS regulation enhances this existing framework with requirements for GS wells that are tailored to the unique nature of large scale GS of CO2. These additional protective requirements include more extensive geologic testi ng, detailed computational modeling of the AoR and
p eriodic re-evaluations, detailed requirements for monitoring and trac king the CO2 plume and pressure front, and extended post-injection monitoring and site care. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment Code: 1340 1.1.3.2 Oppose use of GS in general



### Individual Comments

Other EPA Comment Codes and Descriptions: 1600 1.3 Risk Associated with CO2 GS Comment: i elieve these wells are extremely dange rous. it would be far better to see that less carbon dioxide is formed. i see little to no effort in that regard and ask for more effort on that. these we lls are an accident waiting to happen. look at how the army orps of engineers built the leveees in new orleans - that is an indication of the quality of cons truction that can ha ppen in the usa.

Response: EPA recognizes that injecting large volumes of CO2 for GS poses unique challenges that, if not properly managed, could endanger drinking water s ources and have other adverse impacts. However, the final, tailored, Class VI re quirements address the large volumes of CO2 injected, its buoyancy,
p otential corrosivity in the presence of water, and potential impurities in the CO2 stream. In addition, EPA expects the tailored permitti ng, siting, construction, operation, mo nitoring, and post- injection site care requirements in the GS rule to prevent leakage from injection formations and protect USDWs. EPA acknowledges the comment on reduction of carbon emissions. This comment is outside the scope of the UIC Program’s authority under the GS rulemaking.

Other EPA Comment Codes and Descriptions: 1430 1.2.1.2 Support EPA's authority to regulate CO2 injection Comment: 43492-43541. We agree EPA has the authority under the Safe Drinking Water Act (SDWA) to propose regulations governing the protect Underground Sources of Drinking Water, but we believe Carbon Dioxide Sequestration Wells are: 1) dangerous and 2) unnecessary and should not promulgated. Also, we believe the

Response: EPA disagrees that properly managed GS projects are dangerous. EPA believes that the GS requirements, which are based on th e long-standing UIC regulatory framew ork and tailored to meet the unique nature of CO2 injection for GS, appropriate ly address endange rment risks to USDWs. The GS rule contains minimum technical criteria for th e permitting, geologic site characterization, AoR and Commenter Name: B. Sachau Letter ID: 0105 Comment ID: 21939

Commenter Name: Geor g e Hollida y , PhD, PE, BCEE Letter ID: 0114 Commenter Or g anization: Hollida y Environmental Services, Inc. Comment ID: 22515corrective action, well construc tion, operation, mechanical integrit y testing, monitoring, financial responsibility, injection well plugging, post-injection site care, and site closure of GS wells, which will ensure that USDWs are prot ected from endangerment.

EPA believes that the creation of a new injection well class (VI) under the existing UIC Program is necessary to enable the deploymen t of GS as a climate change mitigation technology in a manner that
p rotects USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 3800 2.3 Proposed Injection Well Construction Requirements (40 CFR 146.86); 5000 2.8 Proposed Well Plugging a nd Post-Injecti on Site Care Requirements Comment: passing a written examination. Further, the Agency proposes to sequester buoyant CO2 until the end-of-time by only requiring 50 years of monitoring (40 CFR 146.93(b)(1)). In addition, EPA proposes using well completion materials not currently developed and proven co rrosion-resistant under carbonic acid corrosive conditions.

The proposed regulations are a formula fo r future disaster: 1) Dangerous to sequester CO2, a supercritica l fluid stored at high pressure (2200± psi): 2)

Response: EPA does not believe that a properly managed GS site is dangerous. The Class VI GS regulation builds upon the long-standi ng protective framework of the UIC program, which has been regulating the injection of billions of gallons of liquids for decades. Th e Class VI GS regulation enhances this existing framework with requirements fo r Class VI wells that are tailored to the unique nature of large scale GS of CO2.

EPA believes that a 50 year post-injection site ca re timeframe represents a reasonable and protective
p ost-injection site monitoring period for most GS pr ojects and available data, including data submitted by commenters, do not support a different default time frame. EPA bases this on a review of research studies, industry reports, and existi ng environmental programs, and ev aluation of public comments. EPA adds that the GS regulation includes a provision that the Director may, attheir lengthen the postinjection site care timeframe if th e owner or operator cannot demonstr ate that movement of the plume and pressure front have ceased and the inject ate does not pose a risk to USDWs (146.93(b)(2)).

EPA disagrees that corrosion-resistant materials and cement do not exist. Industry experience of many decades in corrosive down-hole situat ions such as acid gas injection and production of natural gas with carbon dioxide and hydrogen sulfide impurities shows that materials are available that can resist corrosive environments. Meyer (2007) lists several t ypes of cements that have been used under such corrosive conditions. EPA acknowledges that studies have likely not be en performed to prove a 50-year life span for corrosion-resi stant materials. However, there are two studies of wells that were exposed to CO2 for approximately 30 years by Carey et al. (2007) and Crow et al. (2008). Although these studies are limited in the number of well material sample s and the number of wells examined, the casing and cement sampled indicate fairly good condition (i.e., fairly significant corrosion resistance) of well materials installed three decades ago. The best availa ble corrosion-resistant materials suited for each GS
p roject will be determined by the Director.

EPA adds that, to address potential risks associated with high pressu res associated with CO2 injection for GS, the final rule, at §146.88(e)(2), requires that owners or operators of onshore Class VI wells Commenter Name: Geor g e Hollida y , PhD, PE, BCEE Letter ID: 0114 Commenter Or g anization: Holliday Environmental Services, Inc. Comment ID: 22519install automatic surface shut-off devices. Owners or operators must also monitor pressure in the injection zone, as required at §146.90(g).

EPA acknowledges that there are limi ted data on this subject, and believes that providing multiple barriers of protection is the most appropriate a pproach to protecting USDW s from endangerment. See the discussion of Class VI well construction requirements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

The Agency plans to, every six years, collect and revi ew project data on early GS projects to determine whether the appropriate amount and types of info rmation and appropriate documentation are being collected, and to determine if m odifications to the requirements are appropriate or necessary.

Comment: Carbon Capture and Storage (C CS) as a False Solution

As carbon capture and storage is increasi ngly discussed as a possible mitigation option by some governments, it is necessary to highlight some critical limitations and concerns surrounding this technology. Serious problems are inherent with any CCS program. CCS is a very cost intensive procedure, it increases the costs of power generation by 40 to 80% compared with conventional
p ower plants (depending on the location of the plant and the storage site, and the transport and capture te chnology used). In addition to the extra costs of operation, the US Department of Energy calculates that installing carbon capture systems will almost double plant cost s.[FN3 3 National Energy Technology Laboratory (NETL), 2007, Cost and Performanc e Baseline for Fossil Energy Plants, N ETL, August 2007, < http://www.netl.doe.gov/ energy-analyses/pubs/Bituminous Baseline_Final Report.pdf>] This will lead to electricity price hikes of anywhere between 21 and 91%.[FN4 4 Rubi n, E et al., 2005. Technical Summary in IPCC Special Report on Carbon Dioxide Capt ure and Storage, B. Metz et al., Editors. 2005, Cambridge University Pres s: Cambridge, U.K.] Additionally, using CCS technology greatly reduces the efficien cy of power plants, up to 30% more fossil fuel must be burned to achieve th e same power output.[FN5 5 Abanades, J C et al., 2005. Summary for Policymakers in IPCC Special Report on Carbon Dioxide Capture and Storage, B. Metz et al., Ed itors. 2005, Cambridge Un iversity Press: Cambridge, U.K.] Finally, CCS produces cons iderable additional long-term costs. Monitoring and verification over decades is necessary to guarantee the retention of the stored carbon dioxide. To have any potential climate benefit, buried CO2 must remain underground forever. However, safe, permanent storage cannot be assured; the world has no experience with the deliberate long-term storage of anything, let alone CO2. The longest r unning storage project, Sleipner in N orway, is only 12 years old. While some geological reservoirs could have the specific combination of phys ical features and chemical processes that trap injected CO2 and esse ntially hold it for all time, th ere is insufficient data or
p ractical experience to know whether there are enough.

Response: EPA does not believe that GS is dangerous. The GS regulation builds upon the long-standing
p rotective framework of the UIC pro g ram, which has been re g ulatin g the in j ection of billions of g allons Commenter Name: Emil y Rochon Letter ID: 0129 Commenter Or g anization: Greenpeace International Comment ID: 23061of liquids for decades. The GS regulation enhances this existing framework with requirements for GS wells that are tailored to the unique nature of large scale GS of CO2. These additional protective requirements include more extensive geologic testi ng, detailed computational modeling of the AoR and
p eriodic re-evaluations, detailed requirements for monitoring and trac king the CO2 plume and pressure front, and extended post-injecti on monitoring and site care.

EPA acknowledges that, because all GS in the U.S. is associated with pilot projects, there are unknowns regarding how GS projects will unfold and the practicalities of permitting, operating, monitoring, and closing a GS project. As a result, EP A is using an adaptive approach to regulating GS. EPA plans, every six years, to collect a nd review data on GS proj ects to determine whether the appropriate amount and types of information and appropr iate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

EPA clarifies that CCS operations and regulation of energy costs ar e not within the UIC Program’s authority. For additional information on EPA’s final regulatory approach, please see the final rule and
p reamble as well as the rulemaking docket.

Comment: The Emperor has no clothes! This all seems like a sham, that will only create a lot of work for some people, cost ta xpayers a lot of money over time, and continue a myth.

Response: EPA does not believe that GS is dangerous. The GS regulation builds upon the long-standing
p rotective framework of the UIC program, which has been regulating the injection of billions of gallons of liquids for decades. The GS regulation enhances this existing framework with requirements for GS wells that are tailored to the unique nature of large scale GS of CO2. These additional protective requirements include more extensive geologic testi ng, detailed computational modeling of the AoR and
p eriodic re-evaluations, detailed requirements for monitoring and trac king the CO2 plume and pressure front, and extended post-injection monitoring and site care. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: railroad system. We do not have as much coal as we have been told anyway, so all of these are very important as we think about this question of what to do and whether we should really be somehow thinking that the only way to address climate change is to burn coal and somehow try to smash a gas back into the
p lanet and hope it does not come back out. It is completely absurd assumption in
p art because we do not have that much coal anyway.

So, putting all that into context as we think about these rules, the sequestration space in our country a nd around the planet, but for now our country is going to be a very valuable commodity, so a fundamental concept behind these rules should be that se questration space should only be used, because we can be pretty sure it is goi ng to fail. We do not know it is probably not going to fail, it may or may not fail in our lifetimes becau se we have got a bunch of old folks in this room, but it -- we can be pretty sure that it will fail. As this countr y moves be y ond the fossil fuel era and into the post fossil Commenter Name: Anon y mous4 Letter ID: 0147 Comment ID: 21734

Commenter Name: Leslie Glustrome Letter ID: 0527 Comment ID: 21411fuel era, how excited are we going to be -- or are future generations going to be about taking care of our carbon dioxide disposals sites? You know, they are going to have other things they are going to be tending to, all the other
p roblems we have left them.

Response: EPA does not believe that GS is dangerous. The GS regulation builds upon the long-standing
p rotective framework of the UIC program, which has been regulating the injection of billions of gallons of liquids for decades. The GS regulation enhances this existing framework with requirements for GS wells that are tailored to the unique nature of large scale GS of CO2. These additional protective requirements include more extensive geologic testi ng, detailed computational modeling of the AoR and
p eriodic re-evaluations, detailed requirements for monitoring and trac king the CO2 plume and pressure front, and extended post-injecti on monitoring and site care.

Comment: So the fact, the concept that somehow th ey are going to be managing these sites for hundreds and thousands of years and payi ng great attention to them is just absurd. And we need to start with that assumption. They are not going to be well monitored and they are going to fail. Carbon dioxide is a gas, it is a corrosive gas and we can assume that it is going to fail in due time and we have got millions of wells around this country. So carbon dioxide space should only be used to sequester carbon dioxide that ha s been used for processes for which there is no reasonable alternative. That ma y be something like making cement or making steel. Our children and grandchildren may want to make that and they may need to use coal to do that.

Response: As described above, EPA does not believe that GS is dangerous. The GS rule contains tailored requirements to address the unique nature of GS, including extensive geologic testing, detailed computational modeling of the AoR and periodic re-evaluations, deta iled requirements for monitoring and tracking the CO2 plume and pressure front, and extended post-injection moni toring and site care.

Comment: 80219 and I am here to comment today on EPA's underground injection control on CO2 and to talk about a number of reasons why this is a really, really bad idea and not someplace we should put billions of dollars.

Response: EPA does not believe that GS is dangerous. The GS regulation builds upon the long-standing
p rotective framework of the UIC program, which has been regulating the injection of billions of gallons of liquids for decades. The GS regulation enhances this existing framework with requirements for GS wells that are tailored to the unique nature of large scale GS of CO2. These additional protective requirements include more extensive geologic testi ng, detailed computational modeling of the AoR and
p eriodic re-evaluations, detailed requirements for monitoring and trac king the CO2 plume and pressure front, and extended post-injection monitoring and site care. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket. Commenter Name: Leslie Glustrome Letter ID: 0527 Comment ID: 21412

Commenter Name: Nanc y LaPlaca Letter ID: 0529 Comment ID: 21493

Commenter Name: Nancy LaPlaca Letter ID: 0529 Comment ID: 21496Comment: And so the lesson for all of us I think is that it is up to us citizens. I have been working on coal issues for two years completely unpaid and myself and my friend filed a complaint against a gasifi ed coal plant that was going to be built here in Colorado, Excel Energy was proposing to build an IGCC plant over 4,000 feet elevation, get a $130 million from the feds to build a gasified coal
p lant here in Colorado and we let them know that this was not going to happen without a fight. They actually withdrew their proposal la st October and are not building one here. However, states like Kentucky, Ohio, Illinois where there is a lot more political pressure, they are still getting stuck with these plants.

Response: EPA clarifies that the regulation of coal gasification power plants is outside the scope of the UIC GS rulemaking. Rather, the purpose of the UIC GS regulation is to ensure that GS is conducted in a manner that protects USDWs from endangerment. EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 6000 3. Cost of the Proposed Rule Comment: Future Gen which some have dubbed Never Ge n which is this prototype clean coal
p lant that was going to be built in Sout h Illinois, but is now up in the air, that was going to cost a whopping $6,500 a kilo watt. To put that in, to compare that to other -- costs of other electr ic generation, wind is about even with escalated costs today about $2,000 a kilowatt to build a plant. Concentrating solar is about $3,000 or $4,000 a kilowatt, maybe $5,000 a kilowatt, but that includes storage, [indecipherable] salt st orage. Nuclear power plants anywhere between $5,000 and $10,000 a kilowatt and incidentally in the energy bill right now, there is somewhere between 90 and 190 billion dollars in giveaways for nuclear industry and the energy policy act of 2008.

Response: EPA clarifies that the GS rule addresses sequestration only, not capture or transportation. Any impacts on the cost of electrici ty are likely to be influenced by all aspects of CCS, including capture, transport, and sequestration.

Comment: And so what have I learned from all of this? That wind is cheap. Energy efficiency is really, really cheap. Concentrating solar is here, it is now, it is working. It costs a fraction of what this gasified coal costs and what are we doing? We [indecipherable] our planet so all the young people that I see in this audience here, I see young people and I am af raid of what the world is going to look like when your hair looks like mine . I am fearful of that and I am fortunate to have a husband and a family that will let me quit my job and work for free full time on this issue so that we can stop this stupidity because all it takes is facts and information. A nd you know, we can whine and the coal industry is spending $100 million to convince us that coal is clean. Nothing can change this basic ratio. One pound of co al burned, three pounds of CO2; a very, very stable molecule that takes a lot of energy to compress, chill and then you
p ump it somewhere. This is absolute madness. Commenter Name: Nanc y LaPlaca Letter ID: 0529 Comment ID: 21497

Commenter Name: Nanc y LaPlaca Letter ID: 0529 Comment ID: 21498And so I will submit my materials online. You know it is interesting, here in Colorado, Excel Energy was fighting a gasified coal plant in Minnesota. I think most of the testimony that we used was from Excel, so they were fighting against by a coal plant in Minnesota because they did not own it, and they wanted to build one here. Why? Because they want to put billions of dollars into [indecipherable] base and force rate paye rs, normal people to pay the bills. It is sort of like this bail out, but right now where you know, the big guys run away with the real cash so that when they make a profit, they get to keep it. When it does not work, they just stick it to the tax payers and so basically this is an incredible [i ndecipherable] and I hope we have the good sense for all the young people and all the people on this planet, the six billion people on the planet who are not part of the problem. They can only deal with what we here in the United States, 5% of the populati on creating 25 to 40% of the problems in the world deal them.

Response: EPA clarifies that the regulation of coal gasification power plants is outside the scope of the UIC GS rulemaking. Rather, the purpose of the UIC GS regulation is to ensure that GS is conducted in a manner that protects USDWs from endangerment. EPA acknowledges the comment. Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment Code: 1350 1.1.3.3 Comments on the need for GS technology



### Individual Comments

Other EPA Comment Codes and Descriptions: 1310 1.1.2.4 Comments on other "out of scope" issues, e.g., pore space ownership; 3460 2.2.2.3 Acceptable correct ive action techniques for GS sites (e.g., cements) Comment: For the past four years, our comp any has been field testing our
p roprietary systems and methods for utiliz ing a low melting point fusible metal alloy to mold in situ plugs in wells to repair gas leakage problems. Our focus has been on repair of vent gas flows that occur because of channels that exist within the cement surrounding production casi ng in wells. Our field tests have been carried out with perm ission of the Alberta Energy Resources Control Board ("ERCB") and under their scrutiny. We presently have a proposal under consideration by the ERCB and the Canadi an Association of Petroleum Producers (CAPP) to add our methods to the approve d well abandonment pr otocols presently under review in Alberta.

We believe our methods are di rectly applicable to th e problem of long term leakage of sequestered GHG from wells th at penetrate a reservoir used for the sequestration. Obviously, it makes neither economic nor environmental sense to capture, concentrate, compress, deliver, a nd inject CO2 into depleted reservoirs or saltwater formations if th ere is not a reliable sealin g method used on Commenter Name: Homer Spence r Letter ID: 0120 Commenter Or g anization: Canitron S y stems Inc. Comment ID: 22071existing wells in that reservoir to pr event the CO2 leaking back into the atmosphere. We believe that our plugging me thods can assure l ong term success in
p reventing this leakage.

We use an alloy of bismuth and tin for our sealing medium. This alloy is nontoxic and will not corrode or cause corrosion in the relevant well environment from either chemical or galvanic proce sses. We believe we can seal a well against gas flow even if the well casi ng has been entirely corroded away. The important properties of the alloy that cause it to be effective are:

1) it expands about 1% by volume when so lidifying from the liquid phase; 2) it is impermeable to gas flow; 3) it seals effectively in dirty oily casing; 4) it has a high specific gravity to facilitate displacement of other fluids present during the deployment process; and 5) it has a very low viscosity and surface tension such that it will enter small fissures, and absorb into and wet
p ermeable rocks such as sandstone.

Only small amounts of the alloy are re quired to form a seal with the differential pressure strengt h required to seal GHG sequestration wells. We set the plugs using an electric heater deployed on a wire line. The procedure is both fast and inexpensive. We have data to back the above contentions, including corrosion tests carried out in a CO2/saltwater environment with a pH of 3 that indicate plug life in steel casing in excess of 10,000 years.

Response: EPA thanks the commenters for the informati on on available well materials. EPA believes that the regulation affords owners or operators flexibility to us e various materials and techniques to
p erform corrective action, provided they meet with the Dire ctor's approval.

Other EPA Comment Codes and Descriptions: 1420 1.2.1.1 Support the GS rulemaking Comment: federal UIC regulations for the Geologic Sequestration of Carbon Dioxide. It is good to see that EPA has proposed a well defined, environmentally protective
p rogram through these rules for the geol ogic sequestration of carbon dioxide. I'm sure that EPA will receive many comments targeted at weakening or removing key parts of the proposed regulatory program ; contrary to the ar guments of some industry voices, geologic sequestration of carbon dioxide is new, untested technology that, if poorly implemented, could have large and long lasting environmental impacts incl uding potentially degrading the quality of our ground water resources (USDW). Please help to encourage the use of this important technology by keeping a strong, environmentally protect ive regulatory program. One early disaster could destroy geologi c sequestration of carbon dioxide as a strategy we can use to respond to rising atmospheric CO2 levels. Caution is warranted in the first set of regulati ons. Once experience with geologic sequestration has been gained, the regul ations may be streamlined where appropriate.

Response: EPA agrees that the implementation of the GS rule in a manner that ensures protection of USDWs from endangerment is important to establishi ng a foundation for further advances in the field of CO2 GS. EPA acknowled g es the need for re g ulator y certaint y : the final GS requirements provide a level Commenter Name: John Stormon Letter ID: 0123 Commenter Or g anization: Washin g ton State Dept. of Ecolo gy Comment ID: 22996of certainty by setting forth unique requirements for GS. These require ments include: the tailored AoR delineation process at §146.84, the types of monito ring appropriate to GS projects at §146.90 and the
p ost-injection site care process at §146.93. For additiona l information on these requirements, please also see the discussion of EPA’s Final Regulatory Appr oach in the preamble to the final GS rule.

To protect USDWs from endangerment and meet the potentially fast pace of GS deployment, EPA is using an adaptive approach to re gulating CO2 injection for GS. The Ag ency plans to collect and review data every six years on GS projects to determin e whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or nece ssary. An adaptive approach will allow regulatory development to
p roceed in time to meet the current and future demands for Class VI permits, while EPA continues to gather data from pilot projects and othe r research as it becomes available.

While EPA agrees with commenters that a stable, predictable, nationally consistent, and workable regulatory framework is important, EP A stresses that the focus of the GS rule is to ensure that, where GS is deployed, it is conducted in a manner that protects USDWs from endangerment.

Other EPA Comment Codes and Descriptions: 1330 1.1.3.1 Support use of GS in general Comment: Given public concern over climate cha nge, pending legislative proposals to sharply curtail carbon dioxide (CO2) em issions, and estimates that energy companies based in Houston and elsewher e could use anthropogenic CO2 to produce billions of barrels of oil that w ould otherwise not be produced, the Partnership believes it is important that carbon capture and storage (CCS) technologies become commercially available as soon as possible. In the near term, strategies employing CO 2 sequestration for Enhanced Oil Recovery (EOR) will help commercialize the carbon capture tec hnology and will help demonstrate the technology necessary for long-term storage of CO2 as a predicate to larger-scale CCS projects. The Partnership strongly s upports regulatory efforts to strengthen incentives for EOR and othe r technologies focused on meeting the challenge of global warming while providing energy and e nhancing our region's economic life.

Response: EPA clarifies that the intent of the Class VI re gulation is not to promote or encourage the use of GS, but, instead to ensure protection of USDWs where GS technologies are deployed. In addition, EPA clarifies that injection of CO2 for the purposes of enhanced oil and gas recovery will continue to be
p ermitted under the Class II program , as long as any oil or gas pr oduction is occurring. The UIC GS requirements will apply to wells used for the purpose of long-term GS.

Comment: 4. Support the development ofinnovative technologies for geologic carbon sequestration;

Response: EPA clarifies that the UIC Program’s au thority under SDWA is focused on ensuring
p rotection of USDWs from endangerment. Promoting the use of GS or asso ciated tec hnologies is outside the scope of the UIC GS rulemaking. For additional information on EPA’s final regulatory approach, please see the final rule and prea mble as well as the rulemaking docket. Commenter Name: Jeff Mosele y Letter ID: 0155 Commenter Or g anization: Greater Houston Partnership (GHP) Comment ID: 21252

Commenter Name: Jeff Moseley Letter ID: 0155 Commenter Or g anization: Greater Houston Partnership (GHP) Comment ID: 21257Comment: CCS Must be Deployed Quickly on a Very Large Scale

Scientists agree that in order to avoi d the worst consequences of climate change, the United States must cut greenhouse gas emissions at least 80 percent below 2000 levels by 2050. [FN7] The scale of CCS projects necessary in the electricity sector to achieve this obj ective is enormous. To store the two billion tons of CO2 emission s from annual fossil fuel electrical gene ration in the U.S. will require at least two hundred CCS projects, each 10 times larger than the largest sequestration project s currently in operation. [FN8] Worldwide, an estimated 6,000 of these projects would be needed. [FN9] Currently, only four large- scale commercial carbon se questration projects exist worldwide. [FN10]

[FN7: Luers, A.L. et al. 2007, How to Avoid Dangerous Climate Change: A target for U.S. emissions reductions. Union of Concerned Scientists, online at http://www.ucsusa.org/assets/documents /global_warming/emissions-targetreport.pdf] [FN8: Benson, S, 2004. Carbon Dioxide Ca pture and Storage in Underground Geologic Formations, Lawrence Berkeley National Laboratory, p. 15, available at http://www.pewclimate.org/docUploads/ 10-50_Benson.pdf (last visited Nov. 25, 2008).] [FN9: International Energy Agency, Near-term Opportunities for Carbon Dioxide Capture and Storage, Global Assessments Wo rkshop in Support of the G8 Plan of Action, June 2007 at p. 7] [FN10: The offshore Sleipner natural gas project in Norway, Snohvit in the North Sea, the InSalah natural gas project in Algeria, and the Weyburn Enhanced Oil Recovery project in Canada. IPCC CCS Technical Summary at 19; Wilson, E., Morgan, M. et al., Regulating the Geologi cal Sequestration of CO2, Environmental Science & Technology, Apr. 15, 2008, at p. 4.]

There is no time to waste to achieve this Herculean task. To have any meaningful role in curbing greenhouse gas emissions, CCS projects must proceed quickly while cognizant that there is no room fo r missteps. A team of international experts recently explained that "a single major accident, resulting from inadequate regulatory oversight, anywhere in the world, could seriously endanger the future viability of GS [geo logic sequestration]." [FN11]

[FN11: Wilson, E., Morgan, M. et al., Regulating the Geological Sequestration of CO2, Environmental Science & Technology, Apr. 15, 2008, at p. 5.]

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. Howe ver, EPA clarifies that the Class VI regulation does not promote or encourage the use of GS, but, instead ensure prot ection of USDWs from endangerment where GS technologies are deployed.

EPA believes that the GS regulation will provide re gulatory certainty and oversight that operators have requested, and allow for the deployment of this key climate change mi tigation technology that could be deployed to reduce CO2 emissions. EPA adds that the GS regulation builds upon the long-standing Commenter Name: Kristin Henr y Letter ID: 0242 Commenter Or g anization: Sierra Environmental Law Pro g ram, Sierra Club Comment ID: 23310p rotective framework of the UIC Progr am, which has been regulating the in jection of billions of gallons of fluids for decades. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Other EPA Comment Codes and Descriptions: 1330 1.1.3.1 Support use of GS in general Comment: While it is not a "silve r bullet", one important tool is the geologic sequestration (GS) of CO2 at properly sele cted and properly regulated sites. Our Environmental NGO Group does not necessari ly have a common view concerning the magnitude of the long-term role of GS in combating climate change, but we are united in recognizing that a transition away from fossil fuels will take time and that GS is likely to be an importa nt part of the near- to medium-term solution. Fortunately, capturing CO2 and permanently sequestering it in certain types of well-selected and well-managed geologic formations is a technology that is ready to begin deployment today. While GS projects can be permitted today under the Safe Drinking Water Act’s (SDWA) UIC program (in fact a number of
p rojects have already been permitted under existing we ll classes), the rules that currently apply to such projec ts were not designe d with geologic sequestration in mind. Thus, the importance of this rulemaking is not that it is needed in order for GS projects to recei ve permits; rather, the rulemaking is important because it can assure that GS projects are regulated under rules that are specifically designed to require GS projects to be done safely and effectively without endangering underground sources of drinking water (USDWs) or, as discussed below, resulting in a risk of release to the atmosphere. For that reason, it is essential that EPA promulgate final ru les for GS in a timely manner that are sufficient to protect USDWs.

Response: EPA agrees that GS is one technology in a portfolio of options, including solar, wind, biomass, and geothermal, that c ould be deployed to reduce CO2 em issions; however these technologies are outside the scope of the UIC GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed to address climate change, projects are perm itted sited, constructed, operated, and closed in a manner that avoids releases of CO2 into USDWs.

Please see the remainder of EPA’s responses to this comment for further details. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemaking docket.

Comment: One of the ways that we're doing that is by challenging coal fire power plants from being built in this day and age. We see this carbon sequestration, excuse me, I have a cold. We see this carbon se questration as not a silver bullet to the carbon problem in our atmosphere.

Response: EPA clarifies that the regulation of coal power plants is outside the scope of the UIC GS rulemaking. Rather, the purpose of the UIC GS regulatio n is to ensure that GS is conducted in a manner that protects USDWs from enda ngerment. For additional information on EPA’s final regulatory approach, please see the final rule and preamble as well as the rulemakin g docket. Commenter Name: Kurt Waltze r Letter ID: 0250 Commenter Or g anization: Clean Air Task Force Comment ID: 22270

Commenter Name: Becki Cla y born Letter ID: 0509 Commenter Or g anization: Sierra Club Comment ID: 21200Comment: We have a joke within the Sierra Cl ub that nature's version of carbon sequestration is called coal. We need to keep it in the ground, then you don't have to figure out how to put it back in the ground.

I see one major flaw with th is permitting process. And again, I'd like to thank, I want to make a point again of than king everybody who works on this permitting
p rocess, because I believe that they 're doing their jobs very well.

However, this is only geological sequestration that's being addressed, it's not the entire life cycle of carbon capture and sequestration. It doesn't talk about the capture and transport of CO2, and it doesn't talk about leakage, and it doesn't regulate anything on air issues.

The entire purpose of this rule as stated on the handout that's available back there, why is the proposed G.S. Rule needed? The capture and injection of CO2
p roduced by human activities for long-term storage is one of a portfolio of options that can reduce CO2 emissions to the atmosphere, and helps mitigate climate change.

The entire purpose of this rule is to k eep CO2 out of the atmosphere, yet we're only allowed to talk about it in terms of how it affects drinking water. This does not make sense. This pe rmit needs to be more comprehensive, it needs to take into consideration not just how it 's going to affect drinking water, but how, how we're going to handle it if it does go back into the atmosphere.

When we're challenging a coal fired power pl ant we talk to the utilities, and we talk to many utilities about how to mi tigate and reduce their CO2 emissions. Many, many, many of them have come to us and said, we're planning on it, we're going to sequester, we're goi ng to put it in the ground.

But it doesn't mean anything unless it's in a permit, if it's not written down, if it's not in a legally binding document it doesn't mean anyt hing. This permit
p rocess doesn't mean anything in terms of global warming emissions reductions if we can't write it down and put it in the permit.

The fact that this has been a piecemeal process is typical in many of the
p rocesses we've seen in EPA, whether it's a coal mine, a coal fired power plant, there seems to be this spiraling effect of, let's talk about water over here, let's talk about air over here, let' s talk about land use over here.

When many of these projects, especially a project of this magnitude, when we're talking about relying on this technology to reduce the global warming emissions in our, in our atmosphere we have a huge goal ahead of us. 80 percent reduction by 2050 is what the scientists are telling us we need to do. If we're going to reach that we need to make sure that we're going to do this well, and it needs to be comprehensive, does not need to be a piecem eal permitting process. Commenter Name: Becki Clayborn Letter ID: 0509 Commenter Or g anization: Sierra Club Comment ID: 21202Response: EPA clarifies that the regulation of coal plants or the use of coal is outside the scope of the UIC GS rulemaking. Rather, the purpose of the UIC GS regulation is to ensure that GS is conducted in a manner that protects USDWs from endangerment.

EPA clarifies that climate change and CO2 emissions reductions are outside the scope of this rulemaking. The purpose of the Class VI GS rule is to ensure that where GS technologies are deployed, GS is performed in a manner that protects USDW s from endangerment. The requirements apply to owners or operators of injection wells us ed to inject CO2 for long-term storage.

For additional information on EPA’s final regulatory appr oach, please see the final rule and preamble as well as the rulemaking docket.

Comment Code: 1360 1.1.3.4 Effectiveness of trapping mechanisms



### Individual Comments

Other EPA Comment Codes and Descriptions: 5280 2.8.2.4 USDW non-endangerment demonstrations Comment: - Page 43519. Consider explicitly referenc ing the work laid out by Benson to support the statement that physical and ge ochemical trapping m echanisms will help to improve the integrity of storag e as time moves forward. This is a critically important "but widely misunde rstood" point about how GS will work in practice. It w ould be good to include at leas t one citation to technical work to back up this point.

o OTC 19244. Multi-Phase Flow and Trapping of CO2 in Saline Aquifers. Sally M. Benson, SPE, Stanford University. Copyrig ht 2008, Offshore Technology Conference This paper was prepared for presen tation at the 2008 Offshore Technology Conference held in Houston, Texas, U.S.A., 5-8 May 2008.

Response: EPA added the Benson study to the final rule pr eamble (and has made it available in the rulemaking docket).

Other EPA Comment Codes and Descriptions: 5240 2.8.2.2 Post injection timeframe (seeking comment) Comment: B. The Proposed 50-year Term for Post-Inj ection Site Care Is Unreasonably Long

Denbury strongly objects to the use of a 50-year timeframe for continuous monitoring during post-inj ection site care. Our objection stems from the relative risks associated with the various phases of geologic storage operations, the recognized progression of various geologic tra pping mechanisms Commenter Name: James Doole y Letter ID: 0156 Commenter Or g anization: Joint Global Change Research Institute, Pacific N orthwest National Laborator y Comment ID: 22665

Commenter Name: Ronald Evans Letter ID: 0215 Commenter Or g anization: Denbury Resources, Inc. (DRI) Comment ID: 24282(which means that risks of unexpected migration diminish over time), the creation of artificial impe diments to financial assura nce and the sagacity of other regulatory proposals.

First, we believe that published and reput able literature suggests that a 50- year timeframe for post-inject ion site care is too long and wholly unrelated to the risks associated with geologic stor age. For well-sited, characterized, operated and managed sites, the risks accumulate during the operational phase, but decline as sites move fr om post-injection site care to closure to eventual long-term care. Prevailing scientific opinion expects the risk profile to diminish with time.[FN35] As Lindene and Trabucchi suggest, "the risk of some events occurring that result in an une xpected release of carbon dioxide more than 10 years after termination of injecti on will become increasingly remote due to geochemistry conditions." [FN36] The geochemistry c onditions they reference include the four main mech anisms which trap CO2 in well-chosen geological formations - 1) structural trapping -- wh ich is addressed in the proposed rule and is not necessary to discuss further here; 2) residual CO2 trapping -- where CO2 is trapped by capillary forces in the interstices of the rock formation, a
p rocess which develops about 10 years af ter injection; 3) dissolution or solubility trapping -- where the CO2 dissolves into the brine found in the geological formation and sinks because th e CO2 saturated brine is more dense than non-CO2 saturated brine, a process taking place between 10 and 100 years after injection; and finally, 4) minera lization or mineral trapping -- which occurs when dissolved CO2 chemically reac ts with the formation rock to produce minerals, a process requiring hundreds of years.[FN37]

Given that the greatest risk of a releas e occurs during the operational stage of a storage project, and that residual a nd dissolution trapping start well in advance of 50 years, it is difficult to understand why a 50-year timeframe for
p ost-injection site care was chosen. A 50-year post-inj ection site care timeframe simply does not correlate to the relative risks associated with geological storage and the function of ge ologic trapping mechanisms that limit the risk of unexpected rel eases of CO2 after the te rmination of injection activity.

Furthermore, other respected models use a much shorter period. For instance, the IOGCC Model Rules and Legislation stipul ate a 10 year post-injection site care
p eriod.[FN38] Under the IOGCC Model, the operator of the storage site is the responsible party and is required to maintain an operational bond for the equivalent of a post-inject ion site care period and until closure. This 10 year
p ost-injection site care period is more plai nly related to the relative risks of geologic storage and the geochemical reac tions discussed above. Also, in the
p reamble, EPA acknowledges that a 30-year post-closure care period is recognized as the industry standard for the injection of hazardous waste.[FN39]

[35] See Intergovernmental Panel on Cl imate Change, Special Report on Carbon Dioxide Capture and Storage, 208 (Bert, Me tz, et al. eds., 2005); see also Sally Benson, "Carbon Dioxide Capture and Storag e: Research Pathways, Progress and Potential," Global Climate & Energy Pr oject Annual Symposium, October 2007, available at http://pangea.stanford.edu/re search/bensonlab/presentat ions/Carbon%20Dioxide%20Capture%20and%20St orage%20-%20Research%20Pathways%20Progr ess%20and%20Potential.pdf (hereafter "Benson 2007").

[36] Chiara Trabucchi and Lindene Patton, "Storing Carbon: Options for Liability Risk Management, Financial Responsibility," Daily Envir onment Report, Bureau of N ational Affairs, pg. 8 (Sept. 3, 2008).

[37] See IPCC Special Report on CCS, s upra n.2, at 208; see also Benson 2007, supra n.35.

[38] See generally IOGCC, "Storage of Carbon Dioxide in Geologic Structures: A Legal and Regulatory Guide for States and Provinces" (September 2007) (publishing Model Statute and Rules for CO2 storage). The proposed 10 year default period for maintaining operator res ponsibility is at Model General Rules and Regulations, Section 2.0 (f) (defini ng "CSP Closure Period" as 10 years unless otherwise designated by the State Regulatory Agency). See also at Section 4.0 (b) (10) (requiring performance bond to be maintained for 10 years after closure of the facility in accordance wi th Section 9.0). The discussion of the Model Statute and Regulation also mentions other potenti al periods of "10 or 29 years, etc." IOGCC, supra, at 30.

[39] See 73 Fed. Reg. at 43,510.

Response: EPA agrees that some owners or operators will be able to demonstrate, in less than 50 years, that the pressure front and plume no longer pose a ri sk of endangerment to USDWs. However, based on studies, EPA believes that the 50-ye ar default time frame is warranted in most cases based on additional review of research studies and reports and evaluation of public comments.

EPA believes that the best way to address all possibilities, while ensuring USDW protection from endangerment, is to set a 50 year de fault post-injection site care timefr ame, with flexibility to: (1) allow the Director discretion to shorten or lengthen the PISC timeframe during the PISC period based on sitespecific data, pursuant to requirements at §146.93(b); or (2) afford the Director discretion to allow a Class VI well owner or operator to demonstrate, based on substantial da ta during the permitting process, that an alternative PISC timefr ame may be appropriate if it ensures non-endangerment of USDWs
p ursuant to requirements at §146.93(c).

EPA believes that a default post-inj ection site care timeframe of 50 year s, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where substantial data exists to demonstrate that an alternative timefram e would be protective of USDWs, or based on data collected during the PISC period, is appropriate to addr ess the range of sites where GS is anticipated to occur, to accommodate site-spe cific circumstances and various geologic conditions, and addresses commenters¿ concerns, while ensuring USDW protection. Both approaches will utilize site-specific data, and be based on pressure monitoring and USDW impacts.

EPA clarifies that, in determini ng the post-injection site care-timeframe for the proposed regulation, EPA reviewed industry reports, existing environmenta l programs, and initial GS research studies. EPA
p rovided a synthesis of pertinent results from GS modeling studies in the preamble to the proposed regulation. Further explanation of this analysis was in cluded in an EPA-prep ared background document that is available in the federa l docket, titled ""Computational M odeling of Underground Injection of Carbon Dioxide for Determination of Area-of-Review and Potential Risk to Underground Sources ofDrinking Water."" Based on review of these studies , modeling results indicate that the CO2 plume stabilization may occur on the ti meframe of 10-100 years after the ce ssation of injection. EPA believes that a 50-year default post- injection site care timefr ame is a reasonable midpoint for most GS projects and available data, including data submitted by commenters, do not support a different default timeframe, and has retained this in the final regulation.

To the comment about the cost of post-injection site care, EPA does not agree that post-injection site care timeframes longer than 30 years will be prohibitively expensive. In fact, EP A believes that postinjection site care monitoring will re present a relatively minor component of total project cost, and will
p rovide an essential leve l of protection from endangerment fo r USDWs. A discussion of the costs attributed to monitoring technologies (used during injection and th e post-injection site care timeframes) is available in the Technology and Cost Document for the GS rule, which is in the federal docket for this rulemaking. EPA believes that it is logical to make use of existing monitoring infrastructure at a GS site in order to ensure USDWs are not endangered.

EPA also recognizes the concerns associated with assuring financial responsibility for the long timeframes over which post-injection site care will be conducted. However, the Agency believes that, in order to protect USDWs from endangerment under the SDWA, opera tors must demonstrate under §146.85 that financial resources are available to plug th e injection well and provi de post-injection site care at the point in time that the first CO2 is injected. EPA is developing guidance on financial responsibility to assist owners or operators in evaluating the requirements of §146.85 and to assist Directors in evaluating financial responsibility demonstrations. The guidance describes the types of financial mechanisms that operato rs may choose to use when eval uating the financial responsibility requirements for GS wells and it wi ll also include a section on how to estimate costs to support accurate financial responsibility demonstrations . The guidance will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Comment Code: 1370 1.1.3.5 US storage capacity



### Individual Comments

Comment: For CCS to have a significant impact in reducing atmospheric concentrations of CO2 to reduce climate change, a significant amount would have to be stored. The IEA estimates that for CCS to deliver a ny meaningful climate mitigation effects by 2050, 6000 projects each inj ecting a million tons of CO2 per year into the ground would be required.[FN10 10 Intern ational Energy Agency (IEA) Greenhouse Gas R&D Programme, 2007. CO2 capture re ady plants, 2007/4, May 2007.] At the moment, it is not clear that it will be technically fe asible to capture and bury this much carbon, i.e. whether there are e nough storage sites, or that they will be located close enough to power plants. National level estimates are largely based on modeled average values and theref ore remain a source of considerable uncertainty.[FN11 11 Gough, C & Shackley, S, 2006. Towards a Multi-Criteria Methodology for Assessment of Geological Carbon Storag e Options, Climactic Change 74, 2006, pp. 141-174.] The vast majority of these estimates quantify technical capacit y assumin g that the whole of a reser voir is accessible to store Commenter Name: Emil y Rochon Letter ID: 0129 Commenter Or g anization: Greenpeace International Comment ID: 23066CO2 in its pore volume. This can easily l ead to unrealistically high numbers as the fraction of pore volume th at can be used for CO2 storage is site-specific and depends on factors such as injection rate, relative permeability, density and mobility of fluids and rock heterogeneity. [FN12 12 Ibid ] Transport of CO2 over distances greater than 60 miles is likely to be prohibitively expensive.[FN13 13 CSIRO submission to th e Australian Parlia mentary House of Representatives Inquiry in Geosequestration Technology, August 2006.] It is important to note however that the more CO2 that is stored, the greater the amount that would be released to the atmo sphere if any leakag e rate is accepted.

Response: The UIC program’s authority under the SD WA focuses on ensuring that underground injection control activities, such as GS projects, are permitted, si ted, constructed, operated, monitored, and closed in a manner that is protective of USDWs. Ensuring storage capacity is outside the scope of the Class VI GS rulemaking.

EPA clarifies that other federal agencies (e.g., DO E and the U.S. Geological Survey) have conducted research on available storage capacity and made dete rminations of the feasibility of capturing and storing CO2 at the scales needed to address climate change. These agencies, along with private entities, have identified large areas for pot ential sequestration in capacity studies. For example, in 2008, USGS initiated development of a methodology for estimating th e capacity to store CO2 in geologic formations of the United States. In 2009, USGS published a proposed, risk-based methodology for GS capacity estimation. This report, Development of a Probabilistic Assessment Met hodology for Evaluation of Carbon Dioxide Storage, is available at http://pubs.usgs.gov/of/2009/1035/ofr2009-1035.pdf and is available in the rulemaking docket.

Comment: EPA contemplates that the electric power s ector "will most likely be the largest
p otential market for carbon capture and sequestration (CCS) technologies, with the potential to reduce CO2 by approximate ly 80-90% at an individual plant." EPA’s figure seems extremel y optimistic and perhaps unr ealistic given what we know about both current demonstration proj ects of carbon separation and geologic sequestration. We do not recommend that a nyone assume that 80-90% of CO2 from the power sector can actually be separate d and STORED or sequestered in all geologic formations given our current know ledge. While separation of CO2 from the other air emissions might be achievab le at 80-90%, presuming this number for geosequestration that EPA offers s eems overly rosy. See 73 Fed. Reg. 44354, 44492. The oil and gas sector does not univers ally store 80-90% of the CO2 that is recycled in its current EOR/EGR operati ons. In our review of descriptions of current EGR/EOR, as much as 95% of th e CO2 can be recycled many times and sometimes the remaining CO2 is ultima tely vented to the atmosphere.

Enhanced Oil Recovery Schematic Show ing CO2 recycling (source: American Geological Institute)

[Please refer to p. 17 of the pdf file for Figure 1.]

Separation and storage capacities may be very different at each geologic formation or subsurface location. APPA is not offering this as a criticism of oil/ g as operations but simpl y explainin g that there are man y m y ths about actual Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23390retention of CO2 in oil/gas recovery operations and how tr anslatable that experience is for the power plant sector. Regardless of the actual future volume

Response: EPA acknowledges this comment. The purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and
p rovide requirements to pr event endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

In a separate rulemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Gas Reporting Program at 40 CFR Part 98 to add repor ting requirements for CO2 injection and geologic sequestration. The greenhouse gas reporting requireme nts build on the requirements outlined in the Class VI GS rule with the additional goals of ve rifying the amount of CO2 sequestered and collecting data on any CO2 emissions to the surf ace from Class VI GS facilities.

Comment: Every other process when we have a carbon free alternative, that should be the first choice and that shoul d be a criteria before carbon, a CCS project is approved because that CCS space, if we are able to find some spaces that are actually able to stand up to really thor ough scientific analysis then that is going to be a very valuable site and it should only be used for processes that do not have a good alternative.

Response: EPA acknowledges this comment. The purpose of the Class VI GS rule is to ensure consistency in permitting underground injection of CO2 at GS operations across the United States and
p rovide requirements to pr event endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. EPA clarifies that approval of GS projects will be based on a demonstration that the CO2 injection will not endange r USDWs. The Class VI GS rule requires the owner or operator to
p rovide extensive information to demonstrate to the Director, as specified at §§146.82 and 146.83, that the CO2 will be containe d within the injection formation. EPA clarifies that siting and approval of facilities for capturing and tran sporting CO2 are outside the scope of the Class VI GS rule.

Comment Code: 1380 1.1.3.6 Deployment of GS



### Individual Comments

Other EPA Comment Codes and Descriptions: 1540 1.2.3.2 Climate change legislation Comment: However, we also believe that there ar e other barriers which may still impede the deployment of CCS, wh ich cannot be addressed th rough existing legislative grants of power. Specifically, there are concerns governing short and long term liability, ownership issues, state and tr ibal sovereignty issues, and possible sequestration on the Outer Continental Sh elf. Therefore, the Program for Interagency Cooperation is proposing legi slation to address more of these Commenter Name: Leslie Glustrome Letter ID: 0527 Comment ID: 21413

Commenter Name: Victor B. Flatt Letter ID: 0103 Commenter Or g anization: The Center of Environment, Energy & Natural Resources Law (EENR Center), Universit y of Houston Law Cente r Comment ID: 22490b arriers. It should be noted that while the Program for Interagency Environmental Cooperation supports the creation of new legislation to deal with CCS, much of the technical requirements which would be determined by the EPA under such proposed legislation are t horoughly addressed in this Proposed Rulemaking, meaning that the work and resear ch done here would be equally useful in implementing the Program ’s Proposed Legislation.

Although the Call for Comments does not request legislative proposals, we
p rovide the entire proposed legislation a nd accompanying white paper to provide context for evaluating whethe r this Proposed Final Rule making should also spur additional legislative acti on. While we support the Proposed Rule and the EPA moving forward with this Rule, the EPA al so has the authority to suggest and comment on proposed legislation that fu rthers the agency’s environmental
p rotection mandates. (42 U.S.C. Sec. 7609) . We believe that in addition to implementing the Proposed Rule, that th e EPA should also examine and suggest federal legislative changes that woul d further reduce legal and regulatory barriers to the deployment of CCS.

Response: EPA clarifies that the SDWA does not provide EPA with specific authority to develop UIC regulations for GS that are not di rectly related to protecting USDWs from endangerment; thus EPA does not have authority under the SDWA to address issu es related to CO2 pipelines, sub-surface property rights, and capture and tran sport of CO2. EPA clarifies that the GS rule does not address the status of CO2 as a pollutant or commodit y. The UIC requirements regulate the injection of fluids. EPA recognizes that liability is an important issue to owners or operato rs but the Agency does not have authority under the SDWA to transfer long term liability from owners or operators to the state or federal government. Therefore, liability remains with the owner or operator.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

Comment: In addition to regulatory clarity, climat e change policy will be needed to define a value for CO2 in order to driv e deployment of CCS. After policy, cost will determine how quickly and widely CCS can be depl oyed. Currently, the value of CO2 is principally limite d to its use in Enhanced Oil Recovery (EOR). The cost of CCS needs to be reduced by implem enting requirements that are necessary and sufficient while not compromising the pr otection of drinking water. These are our principal concerns with the draft re g ulation: Commenter Name: James Childress Letter ID: 0158 Commenter Or g anization: Gasification Technolo g ies Council (GTC) Comment ID: 237551 . EPA needs to categorically exclude CO2 specifically intended for geologic storage from the definition of RCRA hazardous waste.

2. EPA must emphatically conclude that CO2 containing trace contaminants does not open any regulatory pathways to subj ecting a geological storage site to Superfund liability.

3. CLASS VI (Underground Injection Control (UIC) permits need to identify the
p otential for hazardous substances that might be generated in geologic formations after facility decommissioning and well closure so that should releases occur, they woul d be federally-permitted.

4. Secondary confinement/contai nment should not be required.

5. CO2 injection should not be restricted only to formations below the lowermost underground source of drinking water.

6. EPA needs to clarify how to demons trate financial responsibility; the
p roposed regulation leaves too much discretion to the Director.

7. EPA should not adopt a pay-in period of three years.

8. The period of post-injecti on site management should be performance-based and not be arbitrarily set at 50 years. .

9. EPA should increase its state stakeholder effort towards uniformity of technical requirements; disparate require ments and processes will increase the time, cost, and comple xity of projects.

10. EPA should not stigmatize geological stor age of CO2 such as can be inferred by having requirements for Class VI wells that are more restrictive than for Class II wells.

11 . Requirements for conversion of any well to a Class VI well should be site and risk dependent.

12. EPA's implied 2017 date for completion of the final UIC regulations is too late to provide regulatory clarity fa ced by CCS project developers today.

Response: The purpose of the Class VI GS regulation is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. The UIC program’s authority under SDWA is focused on ensuring that GS projects are sited, constructed, operated, monitored, and closed in a manne r that is protective of USDWs. EPA adds that setting a value for CO2 (i.e., a price per ton) is out side of the scope of the Class VI GS rulemaking.

EPA acknowledges that GS fall s within the broader context of CCS a nd the need for regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, the Office of Water coordinated with other Agency program offices and across federal agencies (e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy Management,Regulation, and Enforcement, formerly the Mine rals Management Service; Bureau of Land Management). The Agency continues to evaluate areas of potential applicability of other Federal environmental statutes in cluding, but not limited to: the Clean Ai r Act; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Research and Sa nctuaries Act to various aspects of GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize re dundancy and maximize efficiencies for owners or operators. For additional information, pl ease see the discussion entitled "How Does This Rulemaking Relate to Other Federa l Authorities and GS and CCS Acti vities?" in the preamble to the final GS rule.

Please see the remainder of EPA' s responses to this comment for further details. For additional information on EPA's final regulatory approach, please see the final ru le and preamble as well as the rulemaking docket.

Comment: Someone has to proactively address this di fficult issue. With all these issues yet to be resolved, a reasonable conclusi on is that commercial deployment of this technology is still years down the roa d. At this point, we ask EPA to lay

Response: EPA clarifies that the Class VI regulations promulgated under Safe Drinking Water Act authority do not promote or encourage the use of GS, but, ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in antici pation of the eventual use of GS to reduce CO2 emissions. EPA believes that the Class VI GS regulations, which build upon the long-standing, protective, regulatory framework of the UIC program, will provide the regulatory certainty and clarity that owne rs or operators have requested.

EPA acknowledges that there are unknow ns associated with early GS project deployment and the long term storage of CO2 for GS. For th ese reasons, the Agency is using an adaptive approach to regulating GS injection. The Agency will, ever y six years, collect and review da ta on GS projects to determine whether the appropriate amount and types of info rmation and appropriate documentation are being collected, and to determine if m odifications to the requirements are appropriate or necessary.

Comment: 2008). At the same time, it is crucial for the regulations to reflect the challenges inherent in cr afting controls for commercial CO2 injection and storage activities when such large-scale commercial operations are only at the nascent stage. Given what we know now, AP PA remains rather skeptical that the large scale operations as envisioned by the popular or trade press (and perhaps EPA’s proposed rule’s preamble) are very possible in the next few decades. DOE’s original estimate that this new commerci alized CCS industry is possible in about 40 years is probably more realistic. Of course, APPA hopes that there are technology breakthroughs and that CCS or GS can be viable on larger scales which also remain protective of USDWs within th e next 15 years. But we believe these larger commercial size pow er plants with > 10 tons of carbon sequestered annually would likely come online after 2025. We hold this hope on CCS in the same context as in hopin g that there will be breakthrou g hs in lar g e capacit y Commenter Name: Skiles Bo yd Letter ID: 0160 Commenter Or g anization: DTE Ener gy Comment ID: 21269

Commenter Name: Theresa Pu g h Letter ID: 0169 Commenter Or g anization: American Public Power Association Comment ID: 23392b attery storage or in storage for wi nd capacity or for new nanotechnology for solar panels. All are needed to achieve improvements in a power plants’ carbon footprint and in reducing criteria pollu tants. While we may hope for technology and infrastructure breakthroughs, we pl an on geologic sequestration based upon cold reality. The last thing that APPA want s is to promise what we might not yet be able to deliver.

Response: EPA clarifies that the Class VI GS regulati ons promulgated under Sa fe Drinking Water Act authority do not promote or encourage the use of GS, but, ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in antici pation of the eventual use of GS to reduce CO2 emissions. EPA believes that the Class VI GS regulations, which build upon the long-standing, protective, regulatory framework of the UIC program, will provide the regulatory certainty and clarity that owne rs or operators have requested.

EPA acknowledges that there are unknow ns associated with early GS project deployment and the long term storage of CO2 for GS. For th ese reasons, the Agency is using an adaptive approach to regulating GS injection. The Agency will, ever y six years, collect and review da ta on GS projects to determine whether the appropriate amount and types of info rmation and appropriate documentation are being collected, and to determine if m odifications to the requirements are appropriate or necessary.

Comment: Promote CCS Development

A CCS policy regime should be designed to encourage CCS, in addition to serving other public goals -- such as promotion of energy security, economic stability. and protection of USDWs, human health and the environment.

Sound Risk Management

Federal and state policy should encourage owners, operators, technology companies, engineering firms, utility regul ators, and others involved in the CCS chain to take appropriate action to ensu re safe and reliable operation of GS sites and systems, minimize risks, and allow CCS to earn broad public acceptance.

Response: EPA clarifies that the Class VI GS regulati ons promulgated under Sa fe Drinking Water Act authority do not promote or encourage the use of GS but, ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in antici pation of the eventual use of GS to reduce CO2 emissions. EPA believes that the Class VI GS regulations, which build upon the long-standing, protective, regulatory framework of the UIC program, will provide the regulatory certainty and clarity that owne rs or operators have requested.

EPA acknowledges that there are unknow ns associated with early GS project deployment and the long term storage of CO2 for GS. For th ese reasons, the Agency is using an adaptive approach to regulating GS injection. The Agency will, ever y six years, collect and review da ta on GS projects to determine whether the appropriate amount and types of info rmation and appropriate documentation are being collected, and to determine if modifications to the requirement s are appropriate or necessar y

. Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23798EPA agrees that input of and part icipation by a wide spectrum of stak eholders is a vital component of successful rulemaking. The Agency appreciates the degree of cooperation, pa rticipation, and active dialogue between the EPA and stakeholders and will co ntinue to work with stakeholders and experts as it implements the Class VI GS rule.

Comment: A. RECOGNITION OF THE IMPORTANCE OF SPURRING THE DEVELOPMENT OF CCS TECHNOLOGY

The Proposed Rule recognizes the value of promoting CCS technology. With further modification and a broade r scope, these regulations could encourage substantially the safe deployment of CC S technologies, support the construction of new fossil fuel-fired generation, prom ote capital formation, and broaden the availability of risk management mechan isms for CCS projects. The costs and benefits associated with protecting USDW s must be the focus of the Proposed Rule, but account has to be taken of th e reality that such protection is inextricably linked to the mitiga tion of climate change risk.

Response: EPA clarifies that the Class VI GS regulati ons promulgated under Sa fe Drinking Water Act authority do not promote or encourage the use of GS, but, ensure consistency in permitting underground injection of CO2 at GS operations across the United States and provide requirements to prevent endangerment of USDWs in antici pation of the eventual use of GS to reduce CO2 emissions. EPA believes that the Class VI GS regulations, which build upon the long-standing, protective, regulatory framework of the UIC program, will provide the regulatory certainty and clarity that owne rs or operators have requested.

EPA acknowledges that there are unknow ns associated with early GS project deployment and the longterm storage of CO2 for GS. For th ese reasons, the Agency is using an adaptive approach to regulating GS injection. The Agency will, ever y six years, collect and review da ta on GS projects to determine whether the appropriate amount and types of info rmation and appropriate documentation are being collected, and to determine if m odifications to the requirements are appropriate or necessary.

Comment: sequestration activities will remain que stionable. In the meantime, EPA may modify the rule and consider proceeding wi th its implementation for depleted oil and gas reservoirs. Since these reservoirs have been extensively studied in the
p ast, it is likely that enough data exists to ensure safe operations at some of the reservoirs under certain conditions.

Response: EPA clarifies that the Class VI GS rule applies to all injection of CO2 into the subsurface for the purpose of long-term storage regardless of the t ype of injection formati on. The Class VI GS siting requirements allow GS projec ts to be permitted if the owner or ope rator can demonstrate, to the Director that a proposed site has geologic format ions suitable to receive and confin e the injected fluids in order to ensure protection of USDWs from endangerment. EPA acknowledges that depleted o il and gas reservoirs associated with ER operations ma y be used for CO2 stora g e and that these sites ma y be some Commenter Name: Frederick R. Eames Letter ID: 0178 Commenter Or g anization: CCS Alliance Comment ID: 23807

Commenter Name: Saba Tahmassebi Letter ID: 0218 Commenter Or g anization: Oklahoma Department of Environmental Quality (DEQ) Comment ID: 21562of the first sites where commercial-scale GS is de ployed. However, these wells can only be permitted if owners or operators can demonstrate that injecti on into other formations meet the Class VI GS requirements.

Comment: Although the rule is geared specifically to ward well operators there are several components that may affect potential upstream industrial clients, and are of great interest to TFI members. In fa ct, EPA must carefully consider the applicability of this rule and ensure that it covers large industrial manufacturers such as nitrogen fertilizer producers.

Response: The purpose of the Class VI GS regulation is to ensure consistency in permitting underground injection of CO2 at GS operations across the United Stat es and provide requirements to
p revent endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions. The UIC program’s authority under SDWA is focused on ensuring that GS projects are sited, constructed, operated, monitored, and closed in a manner that is protective of USDWs. EPA clarifies that the Class VI GS regulation applies to all injection of CO2 for th e purpose of GS, regardless of the source of the CO2. Requiring or setti ng standards for upstream generators of CO2 is outside the scope o f the Class VI GS rulemaking.

In a separate rulemaking under authority of the Clean Air Act, EPA is amending the Greenhouse Gas Reporting Program at 40 CFR Part 98 to add repor ting requirements for CO2 injection and geologic sequestration. The greenhouse gas reporting requireme nts build on the requirements outlined in the Class VI GS rule with the additional goals of ve rifying the amount of CO2 sequestered and collecting data on any CO2 emissions to the surface from GS facilities.

Comment: Global warming has to be attacked on se veral different layers, clean energy should be first, energy efficiency should be first, using less , having renewable energies, wind and solar, and reducing the need for fossil fuels to be burned. We believe that is actually the way to ke ep carbon out of the atmosphere and not j ust figuring out how to put it in the ground and hoping it'll stay there.

Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in these technologies is outside the scope of the Class VI GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, proj ects are permitted, sited, constructed, operated, and closed in a manner that protec ts USDWs from endangerment.

Comment: While we acknowledge that geologic carbon sequestration has been identified as a means to combat climate change, we ur ge caution as we proceed with this technology. Thank you. Commenter Name: Bill Hertz Letter ID: 0500 Commenter Or g anization: Fertilizer Institute Comment ID: 21206

Commenter Name: Becki Cla y born Letter ID: 0509 Commenter Or g anization: Sierra Club Comment ID: 21201

Commenter Name: C y nthia Lane Letter ID: 0528 Commenter Or g anization: American Water Work s Association (AWWA) Comment ID: 21392Response: EPA agrees that GS is one technology in a portfolio of options, including energy conservation, efficiency improvements, and the use of alternative fuels and renewable energy sources, that could be deployed to reduce CO2 emissions. However, the use of and investment in these technologies is outside the scope of the Class VI GS rulemaking. The Class VI GS requirements are designed to ensure that, where GS is deployed, proj ects are permitted, sited, constructed, operated, and closed in a manner that protec ts USDWs from endangerment.

Comment: And secondly, I do have to doubt the capabil ity of these DOE f unded projects to
p rovide the ultimate or de ciding vote if you like on how to regulate and how to craft the regulatory language. I think there is, there will be so me lessons that will be learned from those. There will be new data available. There will be some research that will take place, but ultimately I think that this program is too little, too late and I also do not think that it is a prerequisite for drafting good rules. There might be some need for revision, but the best way to get that experience and to that knowledge is to move ahead with a handful or two of large scale injections and that will be th e best possible learning experience.

Response: The final rule is based on the most recent GS-related data, information, and scientific research available. In addition to laboratory studies and modeling research that provide relevant information on GS, the Agency is also collecting and analyzing GS project data and permit information from a variety of sources. Most notably, EPA has evaluated permits and review ed operational data and information associated with the seven regional ca rbon sequestration partners hips funded by the U.S. Department of Energy and coordinated through the National Energy Technology Laboratory. EPA believes that this data forms a solid basis for fina lizing the Class VI GS requirements, and there is no reason to wait until all phases of the DOE demonstration tests are complete. Nevertheless, EPA anticipates that future experimental and full-scale projects will conti nue to inform the technology, and is therefore using an adaptive rulemaking approach. EPA plans, every six ye ars, to collect and review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate
or necessary.

Other EPA Comment Codes and Descriptions: 2400 1.8 Comments on EPA's adaptive rulemaking
p rocess Comment: Climate change will not wait and I th ink it will have a profound effect on drinking water results itself and I really do believe that USDWG will suffer if we do nothing about climate change. And I think sequestration as I said can be effective.

I would like to end with a note on scal e and timing. I do not believe that we are ready to proceed with wide scale de ployment of sequestration all around the country. It is something we saw a hundred permit application as soon as rules
p romulgated and I do think this is prematur e. We are not ready to move in that direction. Nonetheless I th ink by the nature of the beast and the current economics of CCS, we will not see that ha ppen. What we are talking about here is an initial wave and an initial set of pro j ects that would be permitted and then Commenter Name: George Peridas Letter ID: 0534 Commenter Or g anization: Natural Resources Defense Council (NRDC) Comment ID: 21456

Commenter Name: Geor g e Peridas Letter ID: 0534 Commenter Or g anization: Natural Resources Defense Council (NRDC) Comment ID: 21465studied intensely. And I think those will inform how we think about sequestration, whether we indeed need or do not need any revisions to the regulations and also how we manage projec ts. I think ultimately if CCS is to deliver on its promise to reduce greenhouse gasses, then yes we will need to deploy this at a wide scale. But this is not something that will happen over five years. Some we will scale up to ove rnight. There will be ample time, study and reassessments.

Response: EPA believes that there is a pot ential that GS may be deployed at a fast pace (e.g., if climate change legislation provides an ince ntive for sequestering CO2 or if other climate policie s or regulations limit CO2 emissions), and that it is necessary to prepare for such an event. EPA's adaptive approach to regulating CO2 injection for GS wi ll allow regulatory development to proceed in time to meet the current and future demand for Class VI permits while recognizing the need to continue to gather data from pilot projects and other research as it becomes available and enhance understanding of the technical and administrati ve aspects of GS deplo y ment, operation, and technolo gy developments.