This comment letter response contains two parts:

(1) The original submittal from the commenter. (2) A data base printout of EPA’s response to each point raised by the commenter.

Notes about the response letters:

• The response letters were generated by a data base used to track the content of all public

comment submittals and ensure that the Agency responds to each. Each comment letter

was assigned a Letter ID that corresponds to the last four digits of the docket number of the
original comment (as posted on www.regulations.gov).

• Each response letter includes: comment text; an EPA

‐ assigned comment code; and an
individual response. These are described and explained below.

• The data base contains Comment text from the letters submitted by commenters.
Many hard copy letters were scanned into electronic format for inclusion in the data

base. As a result, there may be some typographical errors attributable to optical

character recognition issues. However, all original submittals were reviewed in the

process of drafting responses to ensure that the comment content was understood and
appropriately addressed.

• The content of each comment letter was divided into topic areas and assigned a unique

Comment ID. Additionally, one or more Comment Codes (i.e., unique topic area ID) was assigned to each discrete point raised by a commenter. This information was added to

the data base. To inform final rulemaking decisions, all comments and information

received on a given topic were reviewed by technical experts in each rule area (e.g., on

construction requirements).

• Following decisions on the final rule requirements, Individual responses were drafted
by topic area to ensure completeness and consistency of the responses with the final

rule and other responses to similar comments. Each discrete point made by a

commenter was given a unique response.

• Upon completion of comment responses, all information was entered into the data base.

Each letter response is a compilation of each comment and its individual response, compiled in the order of the original comment letter. As a result of this process, there is
repetition in the response text. The Agency believes this approach ensures completeness

and attention to each comment letter that was submitted.

• All comments in a topic area were reviewed, evaluated, and responded to concurrently.

Responses on each topic area are compiled and are also available in the rulemaking docket.Organization Name: Oklahoma Department of Environmental Quality

Submitter’s Representative: Saba Tahmassebi, Ph.D., P.E.

Government Agency Type: State

Government Agency: Oklahoma Department of Environmental Quality

General Comments:

Please consider t he following comments:

1. Delay the proposed schedule for the implementation of the final rule.

With the current state of technology, there does not appear to exist enough data to determine whether

geologic sequestration of carbon dioxide can be accomplished i n a safe manner. In f act, in its preamble

to the proposed rule, EPA states that conducting larg e volume carbon storage tests are necessary to
demonstrate that large

- scale CO2 injection and storage can be achieved safely and economically. The

preamble als o suggest s that the DOE

- sponsored “Deployment Phase” of research is likely to provide the

necessary data to make this determination. The Deployment Phase is scheduled to be completed in

2017. Therefore, EPA will not have enough data to adequately determi ne that large

- scale

implementation of the rule is safe until after 2017 when the data is gathered and analyzed.

Oklahoma DEQ recommends that EPA postpone finalizing the rule until after 201 7 to include the results

of the pilot studies. Without the benefit of considering the results of these studies, the safety of

geologic sequestration activities will remain questionable.

In the meantime, EPA may modify the rule and consider proceeding with its implementation for

depleted oil and gas reservoirs. Since the se reservoirs have been extensively studied in the past, it is

likely that enough data exists to ensure safe operations at some of the reservoirs under certain

conditions.

2. Reconsider s hifting the burden to the States when not enough information is avail able.

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 shifted to the states. Examples include corrective

action methodology for aban doned wells, materials used in construction of the wells, and the use of

tracers among other issues.

Oklahoma DEQ recommends that EPA prepare guidance documents to address the above concern s.3. Preclude aquifer exemptions.

It appears that EPA has struggled with balancing the perceived ben efits of geologic sequestration with

the need to protect USDWs. In much of the proposed rule, EPA sets a foundation for protecting the

US DWs by including specif ic requirements . EPA then diverges from this foundation by suggesting that if

it is not feasible to protect the USDWs, one may still proceed with sequestration activitie s by exempting

the aquifers. In this instance, it appears that EPA co nsiders the benefits of geologic sequestration to
overweigh the need to protect USDWs.

Oklahoma DEQ recommends that EPA not consider aquifer exemptions for geologic sequestration.

4. Re examine the standard for injection pressure.

The proposed rule se ts a limit on i n jection pressure that is less than 90 percent of the fracture pr essure of the injection zones. EPA may be aware that injection zones may also include sealed or closed

fractures that are not permeable. These fractures may re

- open at pressu res below the 90 percent

requirement providing a conduit for fluid migration.

Oklahoma DEQ recommends that EPA consider the effect on the sealed and closed fractures and modify

the maximum pressure requirement accordingly.

5. Clarify jurisdiction across s tate 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 lines, will the permittee be required to obtain a UIC

permit from the neighboring state? If so, what kind of permit? In addition to re quiring monitoring and

financial assurance, would the neighboring state also set limits on the injection rates? Etc.

Oklahoma DEQ recommends that EPA clarify jurisdiction across state lines.

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Contact information:

Saba Tahmassebi, Ph.D., P.E.
Chief Engineer, Land P rotection Division Oklahoma department of Environmental Quality

P. O. Box 1677 Oklahoma City, OK 73101

- 1677 Phone: (405) 702

- 5142 Fax: (405) 702

- 5101
Email: Saba.Tahmassebi@ deq.ok.govLetter ID: 0218

Commenter: Saba Tahmassebi Organization: Oklahoma Department of Environmental Quality (DEQ)

Letter ID: 0218 Comment ID: 21561 Letter Lines: 19 to 33

Comment Code: 1510 1.2.2.3 Need for additional study

Comment Code: 1850 1.4.2 CO2 GS Field Research

Comment: 1. Delay the proposed schedule for the impl ementation of the final rule. With the current state of technology, there doe s not appear to exist enough data to determine whether geologic sequestration of carbon dioxide can be accomplished in a safe manner. In fact, in its pream ble to the proposed rule, EPA states that conducting large volum e carbon storage tests are ne cessary to demonstrate that large-scale CO2 injection and st orage can be achieved safely and economically. The preamble also suggest s that the DOE-sponsored "Deployment Phase" of research is likely to provi de the necessary data to make this determination. The Deployment Phase is scheduled to be completed in 2017. Therefore, EPA will not have enough data to adequately determine that largescale implementation of the rule is sa fe until after 2017 when the data is gathered and analyzed. Oklahoma DEQ recomm ends that EPA postpone finalizing the

rule until after 2017 to include the results of the pilot studies. Without the benefit of considering the results of th ese studies, the safety of geologic sequestration activities will remain ques tionable. In the meantime, EPA may

Individual Response: EPA agrees that continued research w ill be integral to development of GS technology, but disagrees that the Agency should wait for the DOE p ilot studies to be complete before finalizing the GS rule. EPA believes th at establishing a regulat ory framework for the future development and deployment of CCS technology protects USDWs from endangerment and will not impede industry adoption of CCS.

EPA believes that sufficient resear ch has been conducted and suffici ent data gathered to proceed with rule promulgation. While developing the GS regulation, EPA evaluated relevant GS research, including projects conducted by the seve n regional carbon seques tration partnerships funded by the U.S. Department of Energy (DOE ) and coordinated through the National Energy Technology Laboratory (NETL), and several international project s. Additionally, EPA's Office

of Water continues to fund research at the Lawrence Berkeley National Laboratory examining the effects of CO2 interaction on ground water a quifers and any potential mobilization of trace elements that may occur. EPA is communicating w ith other research organizations and academic institutions including, among others, Princet on University, Massachusetts Institute of Technology, and Montana State University, wher e specific research on geologic sequestration, injection well materials, and CO2 monitoring tech niques is in progress. EPA is also working with DOE, USGS, and others to identify tools and training techniques th at will provide GS permitting assistance and technical expertise as appropriate. Additionally, EPA's Office of Research and Development (ORD) is undertaking multiple research efforts on GS. Topics of

1research include bolstering di fferent default thermodynamic databases to include more comprehensive information on aqueous complexes and solid-phases that contain

carbonate/bicarbonate and toxic elements for which EPA has a listed maximum contaminant level (MCL) for safe drinking water.

ORD's National Center for Environmental Resear ch (NCER) awarded six Science To Achieve Results (STAR) grants in the Fall of 2009 to re cipients from major universities and institutions within the scope of the "Integrated Design, Modeling and Mon itoring of Geologic Sequestration of Anthropogenic Carbon Dioxide to Safeguard S ources of Drinking Water" research area. These projects, which started in late 2009, include thes e lead institutions with specific topics of investigation: Clemson Universi ty will study potential impacts to drinking water aquifers of CO2-rich dissolved brines; the University of Illinois-Urbana will conduc t research related to reducing hydrologic and geochemical uncertainties associated with CO2 sequestration in deep, saline reservoirs; the University of Texas at Austin will assess appropriate monitoring approaches at geologic sequestration sites; the University of Utah will integrate design, monitoring, and modeling of GS to assist in developing a practical methodology for characterizing risks to USDWs; Columbia University will conduct laboratory experiments on shallow aquifer systems to improve understanding of geochemical and micr obiological reactions under low pH/high CO2 stress; and Princeton Univ ersity will develop a set of computational

tools to model CO2 and brine movement associated with GS.

EPA is using an adaptive approach to re gulating GS under the UIC Program. Even after finalization of the GS regulation, the Agency plan s to collect and review data every six years on GS projects to determine whether the appropr iate amount and types of information and documentation are being collected, and to determ ine if modifications to the requirements are

necessary.

Letter ID: 0218 Comment ID: 21562 Letter Lines: 33 to 37

Comment Code: 1380 1.1.3.6 Deployment of GS

Comment: sequestration activities will remain ques tionable. In the meantime, EPA may modify the rule and consider proceeding w ith its implementation for depleted oil and gas reservoirs. Since these reservoirs have been extensively studied in the past, it is likely that enough data exists to ensure safe operations at some of

the reservoirs under certain conditions.

Individual Response: EPA clarifies that the Class VI GS ru le applies to all injection of CO2 into the subsurface for the purpose of long-term storage regardless of the type of injection formation. The Class VI GS siting requirements a llow GS projects to be permitted if the owner or operator can demonstrate, to the Director that a proposed site has geologic formations suitable to receive and confine 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 may be used for CO2 st orage and that these sites may be some of the first sites where commercial-scale GS is deployed. However, thes e wells can only be permitted if owners or

2operators can demonstrate that injection into other formations meet the Class VI GS requirements.

Letter ID: 0218 Comment ID: 21563 Letter Lines: 39 to 47

Comment Code: 1200 1.1 General comments about the rulemaking

Comment Code: 1435 1.2.1.3 EPA should develop guidance

Comment: 2. Reconsider shifting the burden to the St ates when not enough information is available. It appears that much research is needed to ensu re 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 addr ess a situation, the burden of addressing the issue is shifte d to the states. Examples include corrective action methodology for abandoned 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.

Individual 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 obtain primacy for Class VI wells will need to describe in their program desc ription the criteria that would be used to make determinations on topics the commenter men tions. See §145.23. EPA adds that it is developing guidance for states and tribes that describes the process of applying for an d receiving primacy for GS Class VI wells under Section 1422 of SDWA, as well as the technical and administrative issues associated with developing GS regulations that are the equivale nt of minimum federal criteria and requirements. These are available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Letter ID: 0218 Comment ID: 21564 Letter Lines: 49 to 57

Comment Code: 4470 2.4.4.4.2 Comments opposing aquifer exemptions in all cases

Comment: 3. Preclude aquifer exemptions . It appears that EPA has struggled with balancing the perceived benefits of ge ologic sequestration with the need to protect USDWs. In much of the proposed rule, EPA sets a foundation for protecting the USDWs by including specific requirements. EPA th en diverges from this foundation by suggesting that if it is not feasible to protect the USDW s, one may still proceed with sequestration activities by exempting the aquifers. In this instance, it appears that EPA considers the benefits of geologic sequestration to overweigh the need to protect USDWs. Oklahoma DEQ recommends that EPA not consider aquifer exemptions for geologic sequestration.

Individual Response: EPA believes that there are limited circumstances where aquifer exemptions for GS may be warranted, and the final GS rule allows for the expansion of the areal extent of existing aquifer exemptions for Cl ass II EOR/EGR wells tran sitioning to Class VI

3injection for GS pursuant to requirements at §§146.4 and 144.7(d). Class VI owners or operators granted expansions of existing Class II EOR/EGR aquifer exemptions for GS projects must meet all of the tailored requirements for GS wells in the final GS rule.

If an owner or operator applies for a Class VI permit to inject CO2 into a previously exempted aquifer (non-USDW) that is lo cated above and/or between USDW s, the permit applicant must also apply for a waiver of the injection depth re quirements pursuant to §146.95 to ensure that if a waiver is granted, USDWs above and below the inje ction zone are protected from endangerment.

The Agency developed the waiver process to ad dress comments and conc erns about current and future drinking water resources and the use of cl imate mitigation technology at appropriate sites. The aquifer exemption requirements in the final ru le provide flexibility and afford owners or operators an opportunity to asse ss and select a suitable GS si te while also preserving USDWs (i.e., formations/aquifers afforded SDWA protec tion). Class VI owners or operators granted expansions of existing Class II EOR/EGR aquifer exemptions for GS projects must meet all of the tailored requirements for GS wells in the fi nal GS rule. EPA agrees with the commenter's concerns about USDW preservation and protection and believes that , in most cases, the injection depth waiver is a more appropriate option than aquifer exemptions for Class VI injection, and that aquifer exemption expansions for GS should be granted in limited circumstances.

EPA adds that all decisions regarding aquifer exem ptions for Class VI wells are at the Director's

discretion. If a Director believes that injection depth waivers ar e not appropriate for a specific site or for a category of formations within their state, the Director has th e authority to not permit such injections.

EPA agrees that future water resources needs ar e an important consideration, and believes that the injection depth waiver process at §146.95 res ponds to concerns about future drinking water resource availability and the need to ensure high quality water remains available in sufficient quantities to supply drinki ng water supply needs.

For additional information on the waiver approa ch and aquifer exemptions for Class VI wells, please see the final rule and pr eamble, as well as EPA's responses to comments on the Notice of Data Availability and Request for Comment.

Letter ID: 0218 Comment ID: 21565 Letter Lines: 59 to 65

Comment Code: 4110 2.4.1.1 Injection pressure limitations

Comment: 4. Reexamine the standard for injection pr essure. The proposed rule sets a limit on injection pressure that is less than 90 percent of the fracture pressure of the injection zones. EPA may be aware that injection zones may also include sealed or closed fractures that are not permeable. These fractures may re-open at pressures below the 90 percent requirement providing a conduit for fluid migration. Oklahoma DEQ recommends that EP A consider the effect on the sealed and closed fractures and modify the ma ximum pressure requirement accordingly.

4Individual Response: EPA notes that during the site char acterization process, owners or operators must submit data about the geology of the site, as specified at §146.82(a), including data on known or suspected faults and fractur es and geomechanical information on fractures, 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. 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.

In response to the concern about reopening of faults at lower pressures than 90 percent of fracture pressure, EPA believes that the requireme nt for the owner or operator to submit data on known or suspected faults and fractures and inform ation on the seismic history of the site will inform the determination of an appropriate pressu re 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 characterization for GS projects to assist owners or operators in meeting the requirements of §146.82 and 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 the necessary geochemical, geomechanical, and geophysical analyses of the injection and confin ing zone. EPA is also developing guidance for primacy agencies that will include recommended a pproaches for evaluating owner or operatorsubmitted data in setting permit conditions. The gu idance will be available on EPA's web site, at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Letter ID: 0218 Comment ID: 21566 Letter Lines: 67 to 73

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

Comment: 5. Clarify jurisdiction across state lines. The proposed rule does not address injection issues across stat e lines. For example, if the pressure boundary and the CO2 plume traverse across state line s, will the permittee be required to obtain a UIC permit from the neighboring st ate? 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.

Individual Response: EPA acknowledges that CO2 plumes may cross state or ev en international boundaries and encourages cooperation and coor dination among permitting authorities. The final Class VI GS rule, at §146.82(a)(2), requires the ow ner or operator to identi fy 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 involve d in any necessary processes; th is new requirement was added to the final rule at §146.82(b). The Agency encourag es transparency in the permitting process and

56 anticipates that State-State/State-Tribal communication on Class VI permitting will facilitate information sharing and encourag e safe, protective projects.

EPA clarifies that the Class VI permit would be issued by the permitting authority in the state

where the wellhead is located.