1.6 – 1.8 –  Responses to Public Comments on Target Geologic Formations, Regulatory

Alternatives, and Adaptive Rulemaking

This file contains responses to public comments on the target geologic formations,

regulatory alternatives, adaptive rulemaking, and public hearings (comment codes 2100

to 2400).  This section includes comments on injection into deep saline formations,

depleted oil and gas reservoirs, unmineable coal seams, basalts, and other formations.  

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 and associated comment codes

Topic Code

1.6 Target Geologic Formations for GS 2100

1.6.1 Deep saline formations 2120

1.6.1.1 Comments in favor of injection into deep saline 2123

1.6.1.2 Comments opposing injection into deep saline 2126

1.6.2 Depleted oil and gas reservoirs 2140

1.6.2.1 Comments in favor of injection into depleted reservoirs 2143

1.6.2.2 Comments opposing injection into depleted reservoirs 2146

1.6.3 Unmineable coal seams 2160

1.6.3.1 Comments in favor of injection into unmineable coal seams 2163

1.6.3.2 Comments opposing injection into unmineable coal seams 2166

1.6.4 Other formation types 2200

1.7 Comments on the Alternatives Considered 2300

1.7.1 Comments on the evaluation process (No comments were submitted for this topic.) 2310

1.7.2 Comments on Alternative 1 2320

1.7.3 Comments on Alternative 2 2330

1.7.4 Comments on Alternative 4 (No comments were submitted for this topic.) 2340

1.8 Comments on EPA's adaptive rulemaking process 2400

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: 2100 1.6 Target Geologic Formations for GS 

Individual Comments

Commenter Name: Kenneth Alexander Letter ID: 0146

Commenter Organization: Old Dominion Electric Cooperative (ODEC) Comment ID: 21710

Other EPA Comment Codes and Descriptions: 3110 2.1.1 Proposed siting requirements (i.e.,

injection/confining zones, trapping mechanism) 

Comment: 3.EPA should not automatically exclude placement of wells in pmiicular geologic 

tructures. The Final Rule should leave the door open for a range of injection 

sites and methods provided the owner or operator can show that the injection and 

storage will be protective of Underground Sources of Drinking Water (USDWs). 

Response: The final rule does not preclude injection into any formations or types of injection sites

provided that the wells meet the final GS rule requirements. The purpose of the GS regulation is to

ensure that injection of CO2 for GS is conducted in a manner that is protective of USDWs. This

includes appropriate site characterization and identification of geologic formations that are amenable

to injection of potentially large volumes of CO2 for long-term storage. The regulation provides

flexibility to owners or operators to select appropriate sites and target formations (under §146.82),

well construction specifics (under §146.86), and injection procedures provided the owner or operator

can demonstrate that the injection and storage will not endanger USDWs and that minimum

requirements for the site are met. 

EPA is using an adaptive approach to regulating GS under the UIC Program. Even after finalization

of the GS regulation, the Agency plans to collect and 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 requirements are appropriate or

necessary.

Commenter Name: Brianne Metzger Letter ID: 0151

Commenter Organization: Spectra Energy Corp Comment ID: 21844

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements

(40 CFR 146.83) 

Comment: I. Large-Scale GS Operations Must Not Impact The Storage Of Hydrocarbon Natural 

Gases. 

One concern with GS is the potential implications for and impact on large-scale 

natural gas storage operations. Under SDWA, hydrocarbon natural gas storage is 

exempt from current UIC regulations governing injection activities. Spectra is 

concerned about the potential implications and impacts on underground gas 

storage from the Proposed Rule. Natural gas storage is regulated by State and 

interstate entities, such as Interstate Oil and Gas Compact Commission (IOGCC), 

that oversee the siting, permitting, design, construction, and operations of 

wells. Within the U.S., natural gas storage is generally located in two major 

geologic formations, porous rock reservoirs and salt caverns. Generally, the 

types of storage fields that will potentially be impacted by the Proposed Rule 

are porous rock reservoirs. Because many of the areas and geologic formations 

considered for GS will be in the same basins and may occur within or in close 

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proximity to the same geologic strata, there is the potential for gas storage 

fields to be adversely impacted by GS. In order to avoid any unintended 

impacts to natural gas storage operations, there are several issues that need 

to be considered. 

First, gas storage wells are regulated by State oil and gas regulatory 

agencies. Individual States have a critical role in protecting and regulating 

the competing economic interests involved in utilizing the subsurface, not only 

for natural gas storage but also oil and gas production or other subsurface 

activities. Many State oil and gas regulations specify well siting or 

construction requirements for any wells that are drilled within a gas storage 

area or penetrate the storage horizon. Spectra suggests that appropriate 

regulatory agencies in individual States be active participants with the EPA in 

the GS permitting process, to ensure appropriate State knowledge of local 

geology is considered in a technical evaluation of the suitability of potential 

GS zones, and for the balanced protection of gas storage and other economic 

interests. We believe the EPA should affirm the authority of the States to 

require the GS operator to comply with all well construction and monitoring 

requirements to protect the integrity of gas storage reservoirs. 

Second, as part of the site selection and GS permit application process, all 

natural gas storage projects within the AoR should be identified on the AoR map 

and assessments performed to determine the potential impact from CO2 or fluid 

migration to the gas reservoir. Such an assessment should also include 

analysis of potential leak paths through faulting, fracturing, or other 

migration paths from injected CO2 in formations in close proximity to gas 

storage reservoirs. 

Third, we would recommend that where GS and gas storage reservoirs are in close 

proximity that additional monitoring be required. We are also concerned about 

the potential impact of hydraulic fracturing of GS wells on natural gas 

storage. We believe that an analysis should be conducted based on the 

proximity (laterally and vertically) of the GS zone to existing gas storage 

reservoirs and the potential for communication with a gas storage reservoir. 

For this reason, we believe it is important that all records relating to well 

logs, cementing records, and casing strings and cementing operations of any GS 

wells drilled within the reservoir or protective perimeter boundaries of a gas 

storage field must be available and accessible to the public. Conversely, and 

for the same reasons, we believe information regarding the proximity of gas 

storage reservoirs to GS wells is equally important and should be readily 

available to the public to ensure the integrity of the CO2 injection operation. 

Response: EPA believes that the extensive requirements 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 permitting 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

ensure that the project is being operated in a manner that protects USDWs from endangerment. 

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Under §146.82(a)(2) owners or operators must identify all injection and production wells, which will

most likely include evidence of and information about the location of natural gas storage sites. The

Director must evaluate this information when determining whether to issue a permit. While the GS

rule does not explicitly require the owner or operator to identify natural gas storage sites within the

AoR, the Director may require additional site-characterization or data collection at his or her

discretion. For example, the Director may require additional monitoring under §146.90(i) to ensure

that GS does not interfere with existing natural gas storage projects. The site characterization

requirements at §146.82 will also help determine the existence and locations of any faults and

fractures.

EPA 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 to owners or operators regarding characterizing the regional geology and

hydrogeology of a proposed GS site as well as performing the necessary geochemical,

geomechanical, and geophysical analyses of the injection and confining zone. Additionally, EPA

expects that this guidance will support permitting authorities as they evaluate initial permits for Class

VI injection wells with technical assistance as needed. The guidance can be found on EPA’s website

at http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm.

EPA expects permitting authorities to retain an administrative record for the project, which at the

discretion of the permitting authority might be available online and at the authority's office. EPA

encourages (but does not require) operators and permitting agencies to begin involving the public by

providing information as early in the GS project development process as possible. 

In response to the comment that state gas agencies should be involved in permitting decisions, EPA

clarifies that the decision to issue a permit rests with the agency implementing the Class VI Program,

as identified in the state's approved primacy application. If a state or tribe chooses not to seek

primacy for Class VI program implementation, EPA will directly implement the program for the

state or tribe. However, the final rule includes a requirement that state and local oil and gas

regulatory agencies and state agencies regulating mineral exploration and recovery must be notified

when a draft Class VI permit is available for public comment, at §124.10(c)(1)(xi).

Commenter Name: Joseph Eutizi Letter ID: 0161

Commenter Organization: San Miguel Electric Cooperative, Inc Comment ID: 21286

Comment: 3. EPA should not automatically exclude placement of wells in particular 

geologic structures. The Final Rule should leave the door open for a range of 

injection sites and methods provided the owner or operator can show that the 

injection and storage will be protective of Underground Sources of Drinking 

Water (USDWs). 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

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as a Class VI well.

Commenter Name: James Stine Letter ID: 0163

Commenter Organization: National Rural Electric Cooperative Association

(NRECA)

Comment ID:

21314

Comment: § EPA should not automatically exclude placement of wells in particular geologic 

structures. The Final Rule should leave the door open for a range of injection 

sites and methods provided the owner or operator can show that the injection and 

storage will be protective of Underground Sources of Drinking Water (USDWs). 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

as a Class VI well.

Commenter Name: James Stine Letter ID: 0163

Commenter Organization: National Rural Electric Cooperative Association

(NRECA)

Comment ID:

21321

Comment: 2. It is counterproductive at this stage in the development of a CO2 GS 

regulatory regime to categorically preclude any potentially feasible injection 

formations as possible long-term storage sites. EPA recognizes that the 

commercial deployment of CO2 GS activities will result in the production of 

large volumes of CO2 for which Owners or Operators will have to locate new and 

environmentally protective injection zones. Therefore, it makes sound policy 

sense for EPA to encourage the identification and utilization of as many 

protective zones as possible, with the prerequisite that any injection site be 

protective of USDWs. To achieve this result, the Final Rule should avoid 

absolute prohibitions on any category of injection site and instead keep all 

options open; injection should be allowed as long as it can be demonstrated that 

injection will be protective of USDWs and meet other applicable conditions for 

Class VI CO2 GS wells. 

Response: As described above, EPA clarifies that the GS rule does not categorically preclude

injection of CO2 into any non-USDW formation types.

Commenter Name: Theresa Pugh Letter ID: 0169

Commenter Organization: American Public Power Association Comment ID: 23363

Comment: Sitting of CO2 GS Wells -- Pg. 32 

APPA believes it is counter-productive at this stage in the development of a CO2 

GS regulatory regime to categorically preclude any potentially feasible injection 

formations as possible long-term storage sites with the exception of sole source 

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aquifers. 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

as a Class VI well.

Commenter Name: Theresa Pugh Letter ID: 0169

Commenter Organization: American Public Power Association Comment ID: 23412

Comment: Siting of CO2 GS Wells 

As discussed above, APPA believes it is counter-productive at this stage in the 

development of a CO2 GS regulatory regime to categorically preclude any 

potentially feasible injection formations as possible long-term storage sites 

with the exception of sole source aquifers. EPA correctly recognizes that the 

commercial deployment of CO2 GS activities will result in the new production of 

large volumes of CO2 for which owners or operators will have to locate new and 

environmentally protective injection zones. It makes sound policy sense for EPA 

to encourage the identification and utilization of as many protective zones as 

possible, with the prerequisite that any injection site be protective of USDWs. 

Injection of CO2 should be allowed as long as it can be demonstrated that 

injection will be protective of USDWs and meet other applicable conditions for 

Class VI CO2 GS wells. APPA offers no opinions on injection of CO2 into coal 

Response: As described above, EPA clarifies that the GS rule does not categorically preclude

injection of CO2 into any non-USDW formation types.

Commenter Name: Erik Silvola Letter ID: 0171

Commenter Organization: Great River Energy Comment ID: 23442

Comment: 3. EPA should not automatically exclude placement of wells in particular 

geologic structures. The Final Rule should leave the door open for a range of 

injection sites and methods provided the owner or operator can show that the 

injection and storage will be protective of Underground Sources of Drinking 

Water (USDWs). 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner or operator can demonstrate to the Director's

5
satisfaction that GS in coal seams, basalts, salt domes, or shales can be accomplished 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: James Rower Letter ID: 0173

Commenter Organization: Utility Solid Waste Activities Group (USWAG) Comment ID: 23480

Comment: To achieve this result, the Final Rule should avoid absolute prohibitions on any 

category of injection site and instead keep all options open; injection should 

be allowed as long as it can be demonstrated that injection will be protective 

of USDWs and meet other applicable conditions for Class VI CO2GS wells. As a 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

as a Class VI well.

Commenter Name: Kenneth Nemeth Letter ID: 0176

Commenter Organization: Southern States Energy Board Comment ID: 23538

Other EPA Comment Codes and Descriptions: 4344 2.4.4.2.2 Comments opposed to setting a

minimum injection depth 

Comment: to USDWs). Equally important, there should not be limitations on formations that 

could be used for GS nor any depth limitations on injection zones. SSEB does not 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

as a Class VI well. 

EPA agrees that it is not appropriate to set a minimum injection depth for GS projects. EPA believes

that a determination of site-suitability for GS (i.e., that subsurface formations will receive and

confine injected CO2) should be made on a site-specific basis. The GS rule, at §146.82, requires the

owner or operator to provide extensive site- and project-specific information to the Director to

demonstrate that the site meets the minimum site criteria at §146.83, that the CO2 will be contained

within the injection formation, and that USDWs will be protected from endangerment. 

EPA acknowledges that there are limited circumstances where injection above the lowermost USDW

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can be performed in a manner that protects USDWs, as long as appropriate protections are in place.

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 injection into non-USDW formations above and/or

between USDWs. The waiver approach requires the submission of extensive, site-specific

information (in conjunction 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 USDWs. The requirements are designed to ensure that the owner or operator, the Director, and the

Regional Administrator consider, on a site specific basis, the implications, benefits, and challenges

associated with GS and ensuring water availability and USDW protection. 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.

Commenter Name: Quinlan J. Shea Letter ID: 0177

Commenter Organization: Edison Electric Institute Comment ID: 23551

Other EPA Comment Codes and Descriptions: 1310 1.1.2.4 Comments on other "out of scope"

issues, e.g., pore space ownership; 3100 2.1 Proposed Geologic Siting Requirements (40 CFR

146.83); 3120 2.1.2 Need to identify additional confining and containment zones (seeking comment) 

Comment: 

EEI agrees that proper site selection is critical to a successful GS project and 

notes that it serves to minimize, if not eliminate, any potential threats to 

drinking water sources that CO2 injection and storage may pose. However, 

several of the proposed requirements are unnecessary from the perspective of 

protecting 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 additional 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 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 containment zones above the primary (i.e.,

lowermost) confining zone can improve USDW protection. These layers could further impede

vertical fluid movement and 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 electric utility who assert that these requirements

promote a flexible, risk-based, site-specific approach to characterizing and permitting a site for GS

projects, and are intended to improve understanding of the project as a whole and promote better

modeling of the site. 

EPA believes that the Class VI requirements, including the level of site characterization required

under §§146.82 and 146.83, appropriately address the unique 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

geologic formations. 

EPA disagrees with the commenter that the GS rule requirements are unnecessary to protect

USDWs. The GS final rule builds upon longstanding programmatic requirements for underground

7
injection that have been in place since the 1980s and that are used to manage over 800,000 injection

wells nationwide. These programmatic requirements are 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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

as a Class VI well.

Commenter Name: Quinlan J. Shea Letter ID: 0177

Commenter Organization: Edison Electric Institute Comment ID: 23578

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring

injection below the lowermost USDW 

Comment: The first such requirement relates to the Agency‘s proposed limitations on 

receiving formations. The proposed regulations would permit project operators 

to inject and store CO2 only beneath the lowermost formation containing USDW. 

Such a categorical limitation on receiving formations is unnecessary, unduly 

burdensome and undesirable for several reasons: 

- Unnecessary for protection of USDW under the UIC program: As a preliminary 

matter, categorically eliminating a body of potential receiving formations is 

simply unnecessary in light of the overall function of the UIC rules. As a 

general proposition, UIC permit applicants must demonstrate that projects will 

not endanger USDW; permit applicants for CO2 injection and storage projects 

would be held to the same standard.[FN4] The proposed rules would also require 

permit applicants to demonstrate that the project will be sited in areas with a 

"suitable geologic system"--consisting of an injection zone of sufficient areal 

extent, thickness, porosity and permeability to receive the total anticipated 

volume of injectate--and a confining zone free of transmissible faults or 

fractures and sufficient to contain the injected stream as well as any displaced 

fluids, considering the proposed maximum pressures and volumes of injection, 

without causing fracturing. Thus, the suitability of the receiving formation 

and the project‘s general protectiveness of USDW will necessarily be evaluated 

as a part of each GS permitting exercise. 

- All projects (and receiving formations) are not created equal: Each potential 

project will possess its own unique characteristics, as will each potential 

project site and receiving formation. A blanket requirement excluding a class 

of potential receiving formations imposed outside the context of actual projects 

is unnecessary, as for any given receiving formation or any given project, there 

may exist other characteristics that serve to provide equivalent or greater 

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protection for USDW. 

- Likely to create public perception issues: Currently, a limitation on 

injections to only those formations below the lowermost USDW is in place solely 

for Class I hazardous waste injection wells. The properties of CO2, while 

unique in some respects, do not require or warrant such heightened treatment. 

Imposing a requirement currently in place only for hazardous waste would be 

likely to create the misperception that CO2 injection wells are analogous to 

hazardous waste injection wells and thus carry analogous risks. Accurate public 

perceptions about the nature of CO2 and the true risks associated with properly 

sited and executed storage projects are crucial to the success of CCS. 

- Likely to hamper commercial deployment of CCS, particularly for enhanced oil 

recovery (EOR) first actors: Much of the experience and expertise associated 

with injection and storage of CO2 that currently exists is the result of several 

decades of experience with EOR and enhanced gas recovery (EGR) operations 

through Class II UIC permits. As CCS gains momentum as a GHG mitigation tool, 

EOR operators may provide not only this wealth of experience and expertise, but 

also the first push toward commercial CCS by seeking to convert existing EOR 

operations to purely storage operations to take advantage of whatever credits 

may eventually become available under climate change legislation or 

regulation.[FN5] Some of those operations inject CO2 into formations that are 

above the lowermost USDW. Under the regulations currently proposed, however, 

existing Class II wells--as well existing CCS pilot projects permitted as either 

Class I or V wells--would be eligible only for the most limited scope of 

"grandfathering": the proposed grandfathering provision, discussed further 

below, would cover only construction requirements and not the remaining 

provisions of the Class VI regulations, including in particular the proposed 

limitation on receiving formations. Thus, existing projects that do not inject 

beneath the lowermost USDW could be left with no ability to convert to Class VI 

GS projects, disincentivizing many potential first actors. Moreover, creation 

of such a disincentive is unnecessary, as the wells at issue would have been 

designed and constructed specifically with injection of CO2 and the protection 

of USDW in mind. 

[FN4] EEI notes that EPA has proposed prohibiting CO2 storage in unmineable 

coal seams, basalts, salt domes and shales because "these formations are limited 

in geographic and geologic distribution in the U.S., and their technological or 

economic viability as GS sites has not been demonstrated." 73 Fed. Reg. 43503, 

col. 2. EEI urges EPA to continue to permit GS projects in these formations as 

Class V experimental wells to facilitate continued research into the potential 

for these formations to safely and economically store CO2, particularly because 

there are some areas of the country without easy access to saline formations or 

depleted oil and gas reservoirs that can be used for GS projects. 

[FN5] Of course, nothing in the proposed rule would prevent any owner or operator 

of a CO2 storage project, regardless of permit class, from seeking credits 

related to its participation in any future cap-and-trade program. 

Response: EPA acknowledges that there are limited circumstances where injection above the

9
lowermost USDW can be performed in a manner that protects USDWs from endangerment, as long

as appropriate protections are in place. 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 injection into

non-USDW formations above and/or between USDWs. The final rule also establishes limited

circumstances under which expansions of the areal extent of aquifer exemptions may be granted for

owners or operators of Class II EOR/EGR wells transitioning to Class VI injection for GS.

Additionally, the final GS rule does not categorically preclude or prohibit injection into any type of

formation. 

EPA believes that these requirements will ensure USDW protection while providing flexibility to

UIC program Directors and owners or operators who undertake CO2 injection for GS. The Agency

believes this approach: 1) responds to concerns about local and regional geologic storage capacity

limitations imposed by the proposed injection depth requirements; 2) allows for a more site-specific

assessment of injection depth for GS projects; 3) accommodates injection into different 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 process responds to concerns about future drinking water

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 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.

While the Agency acknowledges the experience gained by the oil and gas industry and other

injection activities, EPA identified unique 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 geologic

formations that warrant the tailored approach in the GS rule. Furthermore, the Agency believes that

wells that inject into non-USDW formations above and between USDWs presents additional

challenges that warrant additional requirements. 

Regarding the suggestion to allow experimental GS wells to continue to operate under Class V, EPA

anticipates that some owners or operators will apply for Class V experimental technology permits for

injection into formations including shallow basalts, coal seams, salt caverns and shales. These

formations may or may not be located above the lowermost USDW or between USDWs. To

facilitate experimental injection for GS and to increase understanding of injection into these

formation types, the Agency is amending the Class V experimental technology guidance. The

guidance will be available on EPA's web site, at

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm. EPA acknowledges that the Class

V experimental technology well sub-classification may be appropriate for these projects, provided

they are experimental in nature. EPA expects that, following the final GS rule, a limited number of

experimental injection projects testing GS technology will continue. EPA anticipates that these

projects will be small-scale and involve limited CO2 volumes. However, if these projects become

larger scale and are no longer experimental, they will need to be permitted as Class VI wells. The

construction, operation or maintenance of any non-experimental Class V GS well is prohibited, at

§144.15.

Commenter Name: Quinlan J. Shea Letter ID: 0177

Commenter Organization: Edison Electric Institute Comment ID: 23580

10
Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring

injection below the lowermost USDW 

Comment: In light of the UIC permitting process’s focus on demonstrating that a project 

will not endanger USDW, EEI proposes that rather than establish a blanket 

limitation on available receiving formations, the Agency rely upon the numerous 

other provisions that serve to protect USDW and allow those provisions to 

operate in the context of actual proposed projects. In the alternative, 

limitations on receiving formations could be left to the UIC program director‘s 

discretion-bounded by appropriate standards for the exercise thereof-for a 

particular project; however, given the case-by-case nature of the permitting 

process and the requirement to demonstrate non-endangerment of USDW, providing 

for the exercise of such discretion is likely unnecessary. 

Response: As described above, 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. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be

permitted as a Class VI well. 

As described above, EPA acknowledges that there are limited circumstances where injection above

the lowermost USDW can be performed in a manner that protects USDWs from endangerment, as

long as appropriate protections are in place. 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

injection into non-USDW formations above and/or between USDWs. 

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.

Commenter Name: Frederick R. Eames Letter ID: 0178

Commenter Organization: CCS Alliance Comment ID: 23849

Comment: A. GEOLOGIC SITING 

1. Target Geological Formations 

EPA discusses the possible target geologic formations for GS of CO2, stating at 

one point that deep saline formations are the leading candidates for GS. It is 

premature to prefer one type of formation over another. Deep saline aquifers 

have had very little detailed investigation at commercial scale to date. By 

contrast, there is a significant amount of information available about depleted 

oil and gas reservoirs. CO2 storage in unmineable coal seams is an area of very 

active research, particularly in certain regions. Industry reports have 

conservatively estimated more than 10 billion tons of potential storage in 

regional coal seams that, if utilized, could result in the incremental 

production of more than 17 Tcf of natural gas. 

Response: EPA believes that saline formations offer the greatest total capacity for GS and therefore

11
will most likely be used for purposes of GS. 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. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be

permitted as a Class VI well.

Commenter Name: Thomas Curtis Letter ID: 0181

Commenter Organization: American Water Works Association (AWWA) Comment ID: 23644

Other EPA Comment Codes and Descriptions: 4322 2.4.4.1.1 Comments in favor of requiring

injection below the lowermost USDW 

Comment: - Injection of carbon dioxide and construction of injection wells should not be 

allowed in or near sole source aquifers, coal seams, earth-quake prone areas, or 

above the lowermost USDWs; 

Response: EPA clarifies that the GS rule does not preclude injection into any non-USDWs nonUSDW formations, provided the site-suitability requirements in the GS rule are met. 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. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the

project may be permitted as a Class VI well.

In response to the comment that GS should not be allowed in areas with high-risk for a seismic

event, EPA clarifies that the GS rule does not allow GS to be performed in seismically active areas

and requires that operators must submit information about the seismic history of and seismic sources

near a proposed GS site, as required at §146.82(a)(3)(v). This information, along with other required

submissions, will be evaluated by the Director, who will determine the suitability of a potential

project site for GS. 

Additionally, the GS rule, at 146.82(a)(5) requires prospective owners or operators to submit

information on all USDWs, which would include sole source aquifers within the AoR. Based on that

information the Director must consider the potential impact of the GS project on all USDWs,

including any sole source aquifers when determining whether GS is acceptable at a given site. EPA

clarifies that a state’s Class VI primacy program may be more stringent then the federal

requirements. For example, a state has the discretion to ban GS projects from taking place in

formations or areas that affect sole source aquifers. EPA anticipates that state permitting authorities

are in the best position to make determinations about the appropriateness of a particular site based on

all available information, including drinking water supply needs.

As described above, the Agency believes that there are limited circumstances where injection above

the lowermost USDW can be performed in a manner that protects USDWs, as long as appropriate

protections are in place. 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 injection into nonUSDW formations above and/or between USDWs. 

12
Commenter Name: G. Graham Holden Letter ID: 0189

Commenter Organization: Oglethorpe Power Corporation Comment ID: 25247

Comment: 3. EPA should not automatically exclude placement of wells in particular 

geologic structures. The Final Rule should leave the door open for a range of 

injection sites and methods, provided the owner or operator can show that the 

injection and storage will be protective of Underground Sources of Drinking 

Water ("USDWs"). 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

as a Class VI well.

Commenter Name: Andy Horn Letter ID: 0196

Commenter Organization: Colorado Ground Water Association (CGWA) Comment ID: 23921

Other EPA Comment Codes and Descriptions: 1610 1.3.1 Risks to USDWs 

Comment: Issue 1. The proposed regulation has no mechanism for the respective State 

authority in each state responsible for administration of water resources to 

remove certain groundwater basins and/or zones with important aquifers from 

consideration as sequestration repositories. 

One of the CGWA’s concerns is the siting of CO2 sequestration projects in major 

sedimentary rock aquifers, near, or in strata underlying major sedimentary rock 

aquifers such as those which are the primary source of drinking or irrigation 

water for large segments of the population or agricultural community. Due to 

uncertainties in the effectiveness of GS at the project-scales being considered, 

siting of GS reservoirs in strata underlying "sole-source" or other "important" 

USDWs, should be avoided, at least until large scale experience validates this 

methodology. Examples of such aquifers include the Denver Basin Aquifers and 

the aquifers of the San Luis Valley. Additional examples of aquifers which may 

be subject to degradation by displaced brines include the alluvial aquifers of 

the South Platte and Arkansas River Valley where they are in contact with the 

subcrops of strata which could be used as GS reservoirs. Colorado’s reliance in 

many locations on deep bedrock aquifers should remove potential GS reservoirs 

from consideration due to the potential for degradation either by migration of 

CO2 or displacement of CO2 reservoir brines into fresh water aquifers. 

Response: The Agency agrees that drinking water is an important resource that needs to be

protected. The primary goal of the UIC Program under the SDWA is to protect USDWs from

endangerment. Consistent with SDWA §1422 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

presence of that contaminant may cause a violation of any primary drinking water regulation or may

adversely affect the health of persons as specified in §144.12.

13
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 identification 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 formation. The Director must consider this information

when determining whether GS is acceptable at a given site. EPA expects that during this evaluation

the Director will consider the potential impact of the GS project on any sole source aquifers.

Additionally, EPA has added a requirement at 40 CFR 124.10(c)(1)(xi) that requires state and local

oil and gas regulatory agencies and state agencies regulating mineral exploration and recovery, the

PWSS program director, and all agencies that oversee injection wells in the state be notified as part

of the public notice process for a Class VI permit.

EPA anticipates that state permitting authorities are in the best position to make determinations about

the appropriateness of a particular site based on all available information, including drinking water

supply needs. EPA clarifies that a state’s Class VI primacy program may be more stringent then the

federal requirements. For example, a state has the discretion to ban GS projects from taking place in

formations or areas that affect sole source aquifers. 

EPA agrees that, in many cases, UIC Directors will have extensive knowledge of which areas are

suitable 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 determine whether a permit for GS

at the site is appropriate.

Commenter Name: Michael Stroben Letter ID: 0209

Commenter Organization: Duke Energy Comment ID: 22685

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 Class VI (seeking comment) 

Comment: TRANSFERENCE BETWEEN CO2 SEQUESTRATION METHODS 

Duke Energy recognizes that there are differences between Class II and Class VI 

wells. Class II wells are associated with enhanced oil and gas recovery which 

can be an avenue for CO2 sequestration. Aside from deep saline formations, other 

potential sequestration areas include coal seams (Enhanced Coal Bed Methane -- 

ECBM), and shale layers. Since EPA’s proposed rule addresses CO2 volumes in 

millions of tons per year, Duke Energy recommends providing as much flexibility 

as possible when addressing potential CO2 sequestration areas so that the rules 

governing CO2 sequestration are fully transferable should more than one 

sequestration method be selected or should circumstances dictate a change from 

GS to the EOR market or vice versa. Duke Energy believes that allowing 

grandfathering of the proposed provisions to address this type of transfer 

should be allowed except when the Director determines that conversion of a well 

between Class II and Class VI would endanger USDW. 

Response: EPA acknowledges that site-suitability 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

any non-USDW formation type, including unmineable coal seams, provided owners or operators can

demonstrate that GS can be performed in a manner that protects USDWs from endangerment. The

14
Agency anticipates that in the near-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). EPA will continue to

review data on early GS projects, including those in unmineable coal seams, to determine whether

the appropriate amount and types of information and documentation are required and being

collected. 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 appropriate or necessary.

With respect to grandfathering, EPA recognizes that the oil and gas industry has decades of

experience injecting CO2 for ER and that many Class V experimental technology wells are

specifically designed for injection of CO2 and are being constructed to Class I non-hazardous waste

well specifications. In the final rule, at §146.81(c), owners or operators seeking to grandfather

existing Class I, II, or V wells for GS must demonstrate that the grandfathered wells were engineered

and constructed to meet the requirements at §146.86(a) and ensure protection of USDWs from

endangerment in lieu of requirements at §146.86(b) and §146.87(a).

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 permit is required for those projects

that are transitioning from the primary purpose of EOR to long term storage of CO2. The final

regulation provides a set of technical factors for the Director to evaluate in making this

determination, at §144.19. EPA believes that this approach provides sufficient 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 discussion 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. 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 longterm 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 UIC program. This guidance

will be available on EPA’s website at

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm. For more information, please see

the discussion on transition of Class II wells in the preamble to the final GS rule.

EPA agrees that many Class I, Class II, and Class V experimental technology wells are designed and

constructed to withstand exposure to CO2. The final GS rule allows the construction of these wells

to be grandfathered 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).

Commenter Name: Diane VanDe Hei Letter ID: 0213

Commenter Organization: Association of Metropolitan Water Agencies

(AMWA)

Comment ID:

22928

Comment: Unintended consequences: There have been unintended consequences in the 

deployment of municipal disposal wells in Florida, and AMWA cautions EPA to be 

15
very cautious in allowing for carbon sequestration wells to be drilled in areas 

that are not protected by a confining layer of bedrock. For example, AMWA 

believes that EPA should exclude certain formations such as basalt, shale, 

fractured karst and coal bed seams from Class VI CO2 injection until more 

research about the appropriateness injection into these formations completed. 

Response: EPA clarifies that the final 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. Specifically, EPA clarifies that §146.83(a) requires the owner or operator to

demonstrate the presence of a confining layer free of transmissive faults or fractures and of sufficient

extent to contain the injected carbon dioxide and any displaced formation fluids; and that the

injection zone is of sufficient areal extent, thickness, porosity, and permeability to receive the total

anticipated volume of the carbon dioxide stream.

The Class VI siting, well construction and operation, monitoring and testing, and post-injection site

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 satisfaction that GS in coal

seams, basalts, salt domes, or shales can be accomplished 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. 

Regarding unintended consequences related to municipal disposal wells in Florida, EPA clarifies that

GS is quite different from the injection of wastewater in Florida. An owner or operator seeking to

characterize a site for GS (pursuant to the requirements at §146.82) and identify both injection

formations and suitable confining units per §146.83 may not be able to meet the requirements and

ensure protection of USDWs due to the nature of karst formations/geology. In addition, the

computational modeling required to delineate the AoR for a GS project would likely predict

inappropriate buoyant flow and eliminate such formations as potential GS sites. 

Commenter Name: Diane VanDe Hei Letter ID: 0213

Commenter Organization: Association of Metropolitan Water Agencies

(AMWA)

Comment ID:

22939

Other EPA Comment Codes and Descriptions: 1510 1.2.2.3 Need for additional study 

Comment: o Effects of CCS on saline aquifers are unknown. CO2 geosequestration modeling 

performed to-date has generally not considered this type of aquifer. This 

modeling must be conducted. 

Response: EPA acknowledges the commenter's concern about water resources and the protection of

USDWs from endangerment. The Agency clarifies that the statutory mandate of the UIC Program—

and the purpose of the GS rule—is to protect current and future underground sources of drinking

water. Under SDWA authority as implemented by the UIC Program regulations, the GS rule

establishes comprehensive, rigorous requirements for permitting, siting, construction, operation,

monitoring, and closure of GS projects. The GS rule's siting requirements found at §146.82, along

with other requirements for construction, operation, testing and monitoring, and post-injection site

care and site closure are designed to prevent the endangerment of USDWs in the vicinity of GS

operations.

EPA disagrees that insufficient modeling and risk evaluation have been conducted to support the GS

16
rulemaking. To develop the GS rule, EPA considered laboratory, modeling, and field research, which

included data from saline aquifers. In addition, the Agency is involved in collecting and analyzing

GS project data and information from a variety of sources. Most notably, EPA has evaluated and

written permits and reviewed operational data and information associated with the regional carbon

sequestration partnership pilot projects funded by DOE and coordinated through the National Energy

Technology Laboratory (NETL), and several international projects. 

EPA agrees that continued research in all GS associated fields will be integral to development of GS

technology. EPA is aware of research by other federal agencies, industry, 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 Comment 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, New Mexico). In the NODA and Request for Comment, EPA also described two

studies by the Lawrence Berkeley National Laboratory on the potential effects of CO2 injection on

ground water and surrounding formations to determine the potential for impacts on USDWs and

human health in the event that a GS project is not properly sited, operated, or managed. 

EPA acknowledges that there may be risks associated with GS in certain formation types. For this

reason, the Agency is using an adaptive approach to regulate GS injection. EPA will collect and

review project data on early GS projects, including those that inject into various formation types, to

determine whether the appropriate amount and types of information and documentation are being

collected. 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 appropriate or necessary.

Commenter Name: Dennis R. James Letter ID: 0214

Commenter Organization: North American Coal Corporation (NAC) Comment ID: 22960

Comment: H. What Are the Target Geologic Formations for GS of CO2? 

This section is a misrepresentation, and in some cases a gross 

misrepresentation, of the types of geologic formations that are suitable for 

geologic sequestration of CO2. The geologic studies of various formations that 

may be viable reservoirs for the storage of CO2 are relatively new. The 

scientists are just beginning to collect the data and make interpretations of 

the potential storage capacities and related issues. Therefore, it is premature 

for this rule to intimate that one type of geologic formation is better than 

another. The rule should instead promote thorough site characterization as a 

way to determine the adequacy of any formation to act as a sequestration 

reservoir. 

The rule does state that there is a vast amount of information already available 

for many depleted oil and gas reservoirs. However, it goes on to discuss the 

many problems that could preclude such a reservoir from being used for 

sequestration. At the same time, the rule states, "All these characteristics 

make deep saline formations the leading candidates for GS". This is a 

predetermination that deep saline formations are preferred over depleted oil and 

gas reservoirs. At any given site, local conditions may make one option better 

17
or worse than another. 

Research is active and ongoing in this area. Many potential geologic formations 

have not even been tested for CO2 storage capacity, let alone identification of 

problems and issues inherent to the geologic environment. Unmineable coal 

seams, basalts, and other geologic formations may all have CO2 storage 

potential. Ruling out any geologic formations by administrative fiat is 

premature and irresponsible. The results of ongoing research need to be 

considered prior to such proposed actions and site specific characterization 

should be the ultimate determinant of a formation’s suitability. 

One additional criterion should be considered in the process of evaluating a 

specific geologic formation for suitability of sequestering CO2: The potential 

conflict of other resources. Other natural resources above, below, or within 

geologic sequestration formations should be considered in any evaluation for 

long term suitability and security. Drilling and mining operations that may 

occur in the future could have a significant impact on a CO2 reservoir. If oil 

or gas wells are drilled through or even near a reservoir, could they affect its 

integrity? Are there coal reserves, that mining of which (surface or 

underground) could damage the reservoir’s seal? If the presence of sequestered 

CO2 complicates or precludes the recovery of other resources, who is responsible 

for the lost resource value or additional costs? 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

as a Class VI well. 

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into

formations such as coal seams, basalts, salt domes, or shales, which have been the subject of limited

experimental projects in the past. For this reason, the Agency is using an adaptive approach to

regulate GS injection. EPA will collect and review project data on early GS projects, including those

that inject into various formation types, to determine whether the appropriate amount and types of

information and documentation are being collected. 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 appropriate or necessary.

EPA acknowledges that site-suitability for GS is dependent on a number of factors and that many

formation types may be suitable for GS. EPA clarifies that the owner or operator of a Class VI well

must demonstrate site-suitability for GS under §146.83. It is the responsibility of the Director to

evaluate the information submitted by the owner or operator with the permit application and to

determine whether GS at a specific site is appropriate.

18
EPA agrees that GS into unmineable coal seams has the potential to allow sequestration while

ensuring USDW protection from endangerment, as described by commenters citing the process of

enhanced methane recovery. The final GS rule does not preclude injection into unmineable coal

seams provided owners or operators can demonstrate that GS can be performed in a manner that

protects USDWs from endangerment. The Agency clarifies that owners or operators of Class VI

wells used for injecting CO2 into unmineable coal seams are subject to the same site

characterization, well construction, operation, monitoring, post-injection site care and site closure

requirements that are required of projects injecting into other formation types. 

Regarding overlap of GS sites, oil and gas sites, or sites containing other resources, EPA notes that

the final 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 program Director under §146.84. In addition, the rule requires the Director to notify the state oil

and gas agency and state mineral exploration and recovery agency as part of the public notification

required for a draft permit, as required at §124.10(c)(1)(xi). EPA expects that these agencies will

inform the Director of any existing natural gas storage facilities or other drilling or mining

operations around the proposed 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 GS. EPA

clarifies that compensation associated with lost resources or additional costs resulting from

interference with oil and gas or other operations is outside the scope of this rulemaking.

Commenter Name: Dennis R. James Letter ID: 0214

Commenter Organization: North American Coal Corporation (NAC) Comment ID: 22964

Comment: One additional criterion should be considered in the process of evaluating a 

specific geologic formation for suitability of sequestering CO2: The potential 

conflict of other resources. Other natural resources above, below, or within 

geologic sequestration formations should be considered in any evaluation for 

long-term suitability and security. Drilling and mining operations that may 

occur in the future could have a significant impact on a CO2 reservoir. If oil 

or gas wells are drill through or even near a reservoir, could they affect its 

integrity? Are there coal reserves, that mining of which (surface or 

underground) could damage the reservoir’s seal? If the presence of sequestered 

CO2 complicates or precludes the recovery of other resources, who is responsible 

for the lost resource value or additional costs? The existing language does 

require seismic data for the area, acknowledging that the geology is not static. 

Potential human activities could also act to disrupt subsurface conditions. 

Response: Under §146.82(a)(2) owners or operators must identify all injection and production wells,

which will most likely include evidence of and information about the location of natural gas storage

sites or enhanced recovery sites. The Director must evaluate this information when determining

whether to issue a permit. The Director may also require additional site-characterization or data

collection at his or her discretion. For example, the Director may require additional monitoring

under §146.90(i) to ensure that GS does not interfere with existing natural gas storage projects. 

EPA adds that the final rule includes a requirement that state and local oil and gas regulatory

agencies and state agencies regulating mineral exploration and recovery must be notified when a

draft Class VI permit is available for public comment, at §124.10(c)(1)(xi). EPA expects that staff

from the different agencies will provide input on whether a proposed site could interfere with other

resource uses.

19
Regarding the commenter's concern about future drilling and mining operations, EPA clarifies that if

an injection well is drilled in the future, the applicable UIC requirements (i.e., based on the well

class) for AoR and corrective action will apply. The UIC program has no authority to address

drilling for other purposes. However, EPA anticipates that any applicable permitting process would

consider prior uses of subsurface formations.

EPA notes that pore space and mineral rights issues and associated economic losses are outside the

scope of this rulemaking.

Commenter Name: Barbara Walz Letter ID: 0216

Commenter Organization: Tri-State Generation and Transmission Association,

Inc.

Comment ID:

22969

Other EPA Comment Codes and Descriptions: 3120 2.1.2 Need to identify additional confining

and containment zones (seeking comment) 

Comment: D. It is counterproductive at this stage in the development of a CO2 geologic 

sequestration regulatory regime to categorically preclude any potentially 

feasible injection formations as possible long-term storage sites. EPA 

recognizes that the commercial deployment of CO2 geologic sequestration 

activities will result in the production of large volumes of CO2 for which 

owners or operators will have to locate new and environmentally protective 

injection zones. Therefore, it makes sound policy sense for EPA to encourage the 

identification and utilization of as many protective zones as possible, with the 

prerequisite that any injection site be protective of underground sources of 

drinking water (USDW). Tri-State supports alternative approaches that would allow 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

as a Class VI well.

Commenter Name: A. James Mayer Letter ID: 0230

Commenter Organization: A. J. Mayer International on behalf of the American

Energy Security Initiative

Comment ID:

21887

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements

(40 CFR 146.83) 

Comment: 4. EPA should provide flexibility in the siting requirements including promoting 

utilization of EOR, Enhanced Gas Recovery (EGR) and Enhanced Coalbed Methane 

Recovery (ECBM) formations for storage. 

Response: 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

20
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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

as a Class VI well. 

EPA acknowledges that site-suitability for GS is dependent on a number of factors and that many

formation types may be suitable for GS. EPA agrees that GS into unmineable coal seams has the

potential to allow sequestration while ensuring USDW protection from endangerment, as described

by commenters citing the process of enhanced methane recovery. The final GS rule does not

preclude injection into unmineable coal seams provided owners or operators can demonstrate that GS

can be performed in a manner that protects USDWs from endangerment. The Agency clarifies that

owners or operators of Class VI wells used for injecting CO2 into unmineable coal seams are subject

to the same site characterization, well construction, operation, monitoring, post-injection site care

and site closure requirements that are required of projects injecting into other formation types.

Commenter Name: Kristin Henry Letter ID: 0242

Commenter Organization: Sierra Environmental Law Program, Sierra Club Comment ID: 23315

Comment: • Initial Class VI wells should only be permitted in oil and gas reservoirs and 

deep saline formations until other formations are further studied. 

Response: EPA clarifies that the GS rule does not categorically preclude injection of CO2 into any

non-USDW formation types, provided owners or operators can demonstrate that GS can be

performed in a manner that protects USDWs from endangerment. EPA recognizes that research on

the feasibility of various types of geologic formations is underway, and it continues to track the

progress of this research. For example, while developing the GS regulation, EPA evaluated projects

conducted by the seven regional carbon sequestration partnerships funded by the U.S. Department of

Energy and coordinated through the National Energy Technology Laboratory (NETL), as well as

several international projects. In addition, DOE's RCSPs are conducting numerous pilot projects that

inject CO2 into a variety of formation types, including saline, basalt, coal seams, and oil and gas

reservoirs. 

EPA acknowledges that there may be risks associated with GS into certain formation types. For this

reason, the Agency is using an adaptive approach to regulate GS injection. EPA will collect and

review project data on early GS projects, including those that inject into various formation types, to

determine whether the appropriate amount and types of information and documentation are being

collected. 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 appropriate or necessary.

Commenter Name: Kristin Henry Letter ID: 0242

Commenter Organization: Sierra Environmental Law Program, Sierra Club Comment ID: 23326

Comment: VI. Class VI Wells Should Be Permitted Only in Oil and Gas Reservoirs and Deep 

Saline Formations. 

21
EPA should not permit injection into unmineable coal seams, basalts, salt domes, 

and shales until further studies are completed and CCS potential in these 

formations is better understood. EPA lacks an adequate scientific basis to 

develop regulations for commercial-scale sequestration projects in these 

formations: "[T]he process of CO2 adsorption to coal has not been proven and the 

chemical reactions of supercritical CO2 within coal formations are not well 

understood." 73 Fed. Reg. 43,492, 43,503. Sequestration in coal seams is "an 

emerging technology that is in the demonstration phase." Id. As far as basalts, 

shales and salt domes, EPA has noted that their "technical or economic viability 

as GS sites have not been demonstrated." Id. 

The IPCC CCS report supports EPA’s conclusions and goes a step further, 

concluding that "basalts appear unlikely to be suitable for CO2 storage" [FN38] 

The IPCC agrees that coalbed storage technology "is not well developed and a 

better understanding of injection and storage processes in coals is needed." 

[FN39] 

[FN38: IPCC CCS § 5.3.5.1.] 

[FN39: IPCC CCS Chapt. 5 Exec. Summary; see also § 5.3.4.] 

Precautionary principles demand that the first Class VI permits are issued for 

injection into geological formations with the greatest degree of scientific 

certainty, where any damages would be minimal - namely, depleted oil and gas 

reservoirs and deep saline formations. Accordingly, initial Class VI wells 

should not include coal seams, basalts, shales, and salt caverns regardless of 

whether they are above or below the deepest USDW. Continued research is 

appropriate for GS projects in these formations. 

Response: EPA disagrees with this comment and believes that site-suitability 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 any formation type provided owners or operators can demonstrate

that GS can be performed in a manner that protects USDWs from endangerment. The Agency

acknowledges that GS into basalts, salt domes, shales, limestone formations, and fractured karst will

likely have limited application, or that owners or operators seeking Class VI permits for injection

into these formations may not be able to meet the final GS requirements by demonstrating protection

of USDWs. 

The purpose of the GS rule is to ensure protection of USDWs, and the rule includes requirements to

ensure that the geologic formations are adequate to receive and confine injected CO2, at §146.83.

The siting, well construction, operational, and other requirements in the GS rule are designed to

ensure that injected CO2 remains within the target formation. 

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into coal

seams and basalts. EPA anticipates that in the short-term, GS into basalts, salt domes, shales,

limestone formations, and fractured karst will continue to be experimental in nature (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 will continue to review data on

early GS projects, including those in such formations, to determine whether the appropriate amount

and types of information and documentation are required and being collected. EPA plans, every six

years, to collect and review data on GS projects to determine whether the appropriate amount and

22
types of information and appropriate documentation are being collected, and to determine if

modifications to the requirements are appropriate or necessary.

Commenter Name: Claire Olson Letter ID: 0260

Commenter Organization: Basin Electric Power Cooperative Comment ID: 22393

Comment: "H. What Are the Target Geological Formations for GS of CO2?" 

Basin Electric urges the EPA to not arbitrarily exclude certain formations for 

the injection of CO2. Rather, determination of appropriate geology for 

sequestration should be site specific. 

Broad exclusions of geological formations would result in the non-utilization of 

large area of potential storage. In addition, exclusion of un-mineable coal 

seams would prevent the recovery of potentially large quantities of natural gas. 

State Directors should have the responsibility of determining whether or not 

injection into coal seams, oil and gas formations, locations above the lowermost 

underground source of drinking water (USDW), etc. should be permissible. Rather 

than a broad exclusion, proper site selection, site characterization and 

engineering should be utilized in determining the suitability of a potential 

sequestration site. 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner or operator can demonstrate to the Director's

satisfaction that GS in coal seams can be accomplished 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. 

Under the Final Rule, EPA believes that state permitting authorities are in the best position to make

determinations about the appropriateness of a particular site based on all available information,

including drinking water supply needs.

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into

formations such as coal seams, basalts, salt domes, or shales, which have been the subject of limited

experimental projects in the past. For this reason, the Agency is using an adaptive approach to

regulate GS injection. EPA will collect and review project data on early GS projects, including those

that inject into various formation types, to determine whether the appropriate amount and types of

information and documentation are being collected. 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 appropriate or necessary.

EPA clarifies that the final rule requires that injection 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

23
final rule.

Comment Code: 2120 1.6.1 Deep saline formations 

Individual Comments

Commenter Name: Anonymous2 Letter

ID: 0133

Commenter Organization: Sierra Club National Global Warming and Energy

Committee and Sierra Club California-Nevada Regional Conservation Committee on

Energy and Climate Change

Comment

ID: 21580

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: USDWs and Exempted Aquifers: Re-evaluate the UIC program's current 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 aquifers currently being used as sources 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 program’s statutory mandate of ensuring the protection of USDWs. The

permitting, siting, construction, operation, monitoring, and post-injection site care requirements in

the GS rule built on a long-standing protective regulatory framework, tailored to the unique

characteristics of CO2 GS. 

EPA recognizes that there is increasing demand for water resources 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 Director must consider whether alternative

injection sites are available; community needs, demands, and supply from drinking water resources;

planned needs, potential 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 the event of contamination

related to the Class VI injection activity.

Commenter Name: Anonymous2 Letter

ID: 0133

Commenter Organization: Sierra Club National Global Warming and Energy

Committee and Sierra Club California-Nevada Regional Conservation Committee on

Energy and Climate Change

Comment

ID: 21605

Comment: C. USDWs and Exempted Aquifers 

24
Recommendation C: Re-evaluate the UIC program's current definition of an 

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. 

The US Army, US Navy, US Coast Guard, FEMA, and NASA all routinely use reverse 

osmosis technology to desalinate seawater (rated at 25,000-35,000 mg/L TDS) for 

drinking water purposes, as do boat owners and cruise ship companies. The Tampa 

Bay region is providing up to 25 million gallons of drinking water per day 

through its seawater desalination plant, while the city of San Diego recently 

approved the construction of a plant that is slated to supply 50 million gallons 

of drinking water per day. Many seaboard municipalities and utility companies 

currently desalinate ocean water for industrial and agricultural uses; others 

are actively considering the installation of desalination plants for residential 

usage. 

As population demands are increasing and many regions are experiencing lessening 

rain and snow falls, the favored groundwater drinking sources with lower TDS 

counts are becoming more scarce. In the near future, it may be necessary for 

landlocked, arid states to use water from aquifers that exceeds the EPA's 

standard for a protected USDW, currently set at <10,000 mg/L TDS. Since saline 

aquifers have been identified by the DOE as having the greatest potential 

storage capacity of all viable types of geologic sequestration sites in the US, 

it is of utmost importance at the outset that all aquifer GS candidates be 

tested for identification as brackish, saline, or briny along a TDS continuum. 

Taking into account the current technology and practices, it would be 

appropriate for the EPA to re-define protected and exempted USDWs within the 

Class VI permitting protocols as those aquifers with sufficient quantities of 

replenishable water to supply a public water system, rated at <35,000 mg/L TDS. 

Response: The Agency acknowledges commenter concerns about water resources and future water

resource availability. However, modifying the definition of a USDW and analyzing water resource

availability is outside the scope of the GS rulemaking. USDWs are defined as aquifers currently

being used as sources 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 program’s statutory mandate of ensuring the protection of USDWs. The

permitting, siting, construction, operation, monitoring, and post-injection site care requirements in

the GS rule built on a long-standing protective regulatory framework, tailored to the unique

characteristics of CO2 GS. 

EPA clarifies that a state’s Class VI primacy program may be more stringent then the federal

requirements. For example, a state has the discretion to ban GS projects from taking place in specific

formations or other areas where there are water resource issues. EPA believes that state permitting

authorities are in the best position to make determinations about the appropriateness of a particular

site based on all available information, including drinking water supply needs

25
Comment Code: 2123 1.6.1.1 Comments in favor of injection into deep saline 

Individual Comments

Commenter Name: Dave Freudenthal Letter ID: 0150

Commenter Organization: State of Wyoming Comment ID: 22219

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring

injection below the lowermost USDW 

Comment: Unfortunately, the overarching framework and specific rule provisions pertaining 

to suitable re-injection locations contemplated in Docket ID No. EPA-HQOW-2008-0390 prematurely exclude consideration of geologic structures with deep 

saline aquifers that occur in Wyoming. By eliminating the use of these deep 

saline aquifers, the rules would effectively preclude Wyoming from participating 

in CO2 sequestration efforts and effectively disregards the technical expertise, 

referenced earlier, that exists in Wyoming. This broad brush, generalized 

approach deprives Wyoming and the rest of the region from viable consideration 

for CO2 sequestration opportunities. 

I ask that you carefully review the comments submitted by the Wyoming State 

Geological Survey (WSGS) which explain why our nation will be much better served 

if the proposed regulations for geological CO2 sequestration are modified. With 

respect to the depth of injection of C02, the proposed rules only allow 

injection at levels below the lowest underground source of drinking water (USDW) 

aquifer. As WSGS explains, the language needs to be modified to read: 

"Geological CO2 sequestration will be allowed in deep saline aquifers in Rocky 

Mountain Laramide Basins (RMLB) unless it can be demonstrated that the injected 

CO2 will have a deleterious effect on USDW." 

This change will allow for the use of geologic formations with deep saline 

aquifers, which we believe can be safely used for the injection of CO2 in 

Wyoming and other western states. If this change is not made, an illogical 

result will occur in which the proposed sequestration rules for CO2 will be more 

onerous than the rules for injecting hydrogen sulfide into deep saline aquifers. 

Response: As described above, EPA acknowledges that there are limited circumstances where

injection above the lowermost USDW can be performed in a manner that protects USDWs from

endangerment, as long as appropriate protections are in place. 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 injection into non-USDW formations above and/or between USDWs. 

EPA believes that these requirements will ensure USDW protection while providing flexibility to

UIC program Directors and owners or operators who undertake CO2 injection for GS.

Commenter Name: John McManus Letter ID: 0294

Commenter Organization: American Electric Power Comment ID: 25306

Comment: We agree that EPA has ample basis for adopting rules to regulate GS in 

hydrocarbon reservoirs and in deep saline formations under the SDWA. For these 

26
types of geologic formations, there is a widespread technical consensus on how 

to assess and manage risks, what data is needed to characterize sites, how to 

select sites, how to conduct injection operations, how to model the behavior of 

CO2 in the reservoir, and how to monitor project performance. 

Response: EPA acknowledges the comment and agrees that GS into hydrocarbon reservoirs and

saline formations is appropriate where a geologic system (e.g., injection and confining zones) is

identified, characterized, and demonstrated to be suitable for receiving and confining injected CO2

without endangering USDWs under §146.82.

Comment Code: 2126 1.6.1.2 Comments opposing injection into deep saline 

Individual Comments

Commenter Name: Diane VanDe Hei Letter ID: 0213

Commenter Organization: Association of Metropolitan Water Agencies

(AMWA)

Comment ID:

22925

Comment: AMWA is also concerned about using saline aquifers for carbon sequestration. In 

a climate-stressed and ultimately water-stressed world, it is quite possible 

that these aquifers will be used as drinking water supplies in the near future. 

For example, EPA states in the rule proposal that deep saline aquifers that have 

>10,000 TDS will account for 88% of geosequestration sites. Many of these 

aquifers may actually be targeted for water supply. 

The experience of drinking water systems in Florida and other areas has 

demonstrated that TDS measurements in USDWs are a moving target. The upper 

Floridan aquifer is currently about 8000 mg/L TDS. However, in pumping this 

already brackish aquifer, the upwelling of more saline waters from below is 

occurring. In addition, some utilities are considering pumping from deeper wells 

with a higher salinity for drinking water supply and using reverse osmosis to 

treat for TDS. 

As the protection of current and future drinking water supplies is paramount, 

AMWA suggests that when there are competing uses in an aquifer, the needs of the 

aquifer for drinking water supply should take precedence over other municipal or 

industrial uses and the risk of unintended impacts on potable water supplies is 

unacceptable. AMWA suggests that EPA require a more rigorous scientific 

evaluation in the final rule about how potential risk to potable aquifers will 

be avoided in the site characterization for a CO2 geosequestration project. 

Response: EPA clarifies that the final rule requires the Director to notify the director of the state

public water system supervision program (PWSS) when a draft permit becomes available for public

comment. EPA expects that the PWSS director will provide input to the Director regarding

competing needs for water resources and whether to grant a permit. 

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

27
rulemaking. USDWs are defined as aquifers currently being used as sources 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 program’s statutory mandate of ensuring the protection of USDWs. The

permitting, siting, construction, operation, monitoring, and post-injection site care requirements in

the GS rule built on a long-standing protective regulatory framework, tailored to the unique

characteristics of CO2 GS. 

EPA clarifies that a state’s Class VI primacy program may be more stringent then the federal

requirements. For example, a state has the discretion to ban GS projects from taking place in specific

formations or other areas where there are water resource issues. EPA believes that state permitting

authorities are in the best position to make determinations about the appropriateness of a particular

site based on all available information, including drinking water supply needs.

Comment Code: 2140 1.6.2 Depleted oil and gas reservoirs 

Individual Comments

Commenter Name: Michael H. Cochran Letter ID:

0108

Commenter Organization: Bureau of Water, Division of Environment, Kansas

Department of Health & Environment (KDHE)

Comment

ID: 21945

Other EPA Comment Codes and Descriptions: 2000 1.5 Need for a New Class of Injection Well;

2146 1.6.2.2 Comments opposing injection into depleted reservoirs 

Comment: 5. Consider developing regulations that actually address an injection/withdrawal 

type project much similar to a natural gas porosity storage system. In this 

scenario the CO2 is contained in a limited, defined geologic trap and the system 

is designed to inject the CO2 or withdraw the CO2 as needed. 

Response: EPA clarifies that the GS rule addresses injection wells designed for long-term

sequestration of carbon dioxide; the Class VI designation and permit requirements are not applicable

to owners or operators that plan to withdraw carbon dioxide. 

The Agency believes that the nature and risks of CO2 injection for the primary purpose of long-term

storage poses unique risks that may endanger USDWs, and therefore has developed new Class VI

regulations to address these risks. Furthermore, the GS requirements adequately address these risks.

Commenter Name: James Dooley Letter ID: 0156

Commenter Organization: Joint Global Change Research Institute, Pacific

Northwest National Laboratory

Comment ID:

22659

Comment: - Page 43503. While it is a widely held belief that much more is known about 

depleted oil and gas (DOG) fields within the US as opposed to DSFs, it is not at 

ll clear if this is true or significant in terms of the proposed Class VI rule 

or in terms of the decision making process a private firm would use to decide 

28
whether to utilize DOG or DSF fields in a commercial CO2 storage project. To 

the extent that there is more known about DOG fields, much of this data is 

proprietary and is in the hands of oil companies and oil field service 

companies. For more than a decade members of the CCS community have been 

seeking access to this presumed treasure trove of geologic data to build a 

national CO2 storage reservoir data base with this presumably high quality data. 

But the data have not been released, likely due to legitimate private sector 

concerns over protecting valuable proprietary information or perhaps this wealth 

of easily exploitable high quality data do not exist at these firms. So if the 

data exist but are not available, it seems immaterial to assert here that a 

significant cost savings could be had by exploiting DOG fields. This has not 

been proven in practice and I believe it might not ever be proven out in 

practice. 

Response: EPA clarifies that the statement presumed that owners or operators planning GS in

depleted oil and gas fields would be the same parties that delineated the field for the purpose of oil

and gas exploration and would have already collected much of the necessary data in the course of

exploration and therefore would realize a cost savings as a result of that previous work.

Commenter Name: Scott Anderson Letter ID: 0295

Commenter Organization: Environmental Defense Fund Comment ID: 26140

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 Class VI (seeking comment) 

Comment: Second, EPA has so far failed to address another urgent need: regulating 

geologic sequestration in hydrocarbon (oil & gas) reservoirs. Instead, the 

proposed UIC rule concentrates on saline formations and addresses hydrocarbon 

reservoirs only in the event that production has entirely ceased. An oilfield, 

however, can continue producing small volumes in perpetuity, making cessation of 

production a meaningless concept as a threshold to entry into the regulatory 

scheme for CCGS. We consider this to be a serious shortcoming of the rule as 

currently proposed. Enhanced Oil Recovery (EOR) is a practice that has been 

taking place for several decades in the U.S., and is likely to play a pivotal 

part in the early years of geologic sequestration deployment. Reservoirs where 

EOR is occurring, or can occur, are generally better characterized than their 

saline counterparts, often have some of the needed infrastructure in place, and 

offer an additional economic incentive for the operation as a result of oil 

production revenues. Many regions in the U.S. possess significant EOR potential 

that remains untapped due the scarcity of acceptably priced CO2. Under climate 

legislation, or a CAA regulatory regime, this situation will change as large 

point sources capture their emissions. We therefore expect EOR to be utilized 

early during geologic sequestration deployment, for economic and practical 

reasons. Accordingly, EPA should prioritize development of airside regulations, 

including monitoring and verification protocols for situations where operators 

desire to simultaneously pursue EOR and geologic sequestration. Airside 

regulations should also be developed for sequestration taking place in oilfields 

where only minor amounts of oil production occur and the operation can no longer 

be considered EOR. 

29
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 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;

Bureau of Land Management). The Agency 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 Comprehensive Environmental Response, Compensation, and

Liability Act; and the Marine Protection, Research and Sanctuaries Act 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 Other Federal Authorities and GS and

CCS Activities?" in the preamble to the final GS rule.

EPA notes that comments related to the development of “air side” regulations for EOR are outside

the scope of the GS rulemaking. However, 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

reporting requirements for facilities that conduct GS (subpart RR) and all other facilities that inject

CO2 underground (subpart UU).

In response to comments on depleted oil and gas reservoirs, EPA believes that injection of CO2 for

the primary purpose of enhancing oil and gas recovery should remain under the Class II Program,

and that the nature and risks of CO2 injection for the primary purpose of long term storage poses

different risks than injection for the primary purpose of ER. EPA therefore has developed new Class

VI regulations to address these unique risks. For more information, please see the discussion on

transition of Class II wells in the preamble to the final GS rule.

Comment Code: 2143 1.6.2.1 Comments in favor of injection into depleted reservoirs 

Individual Comments

Commenter Name: Matt Toner Letter ID: 0117

Commenter Organization: Hydrogen Energy International Comment ID: 22059

Comment: Oil and Gas reservoirs have proven capable of containing waterbuoyant fluids and 

gases for millions of years. These reservoirs are well studied and they offer 

the best opportunity to kick-start largescale geologic storage of CO2 - building 

on 100 years of oil field operating experience and adding insights which can be 

applied to saline storage. 

EPA recognition of anthropogenic EOR + storage as a valid method of geologic 

sequestration, subject of course to appropriate measurement, monitoring and site 

closure, will provide much needed economic incentive to near-term Carbon Capture 

and Storage efforts, while longer-term Cap & Trade or Taxation schemes develop, 

in support of saline storage options. 

Response: EPA acknowledges the comment and agrees that depleted oil and gas fields are promising

formations for GS, provided the Class VI siting, well construction and operation, monitoring and

30
testing, and post-injection site care and site closure requirements are met under today’s final rule.

EPA adds that injection of carbon dioxide for the purposes of enhanced oil recovery is classified as

Class II injection, not Class VI, and will require a Class II permit. Wells for which the primary

purpose is long term sequestration are considered Class VI wells. EPA further clarifies that the GS

rule is not intended to promote a preference for GS in any particular formation type, to address use

of resources, or to reduce costs associated with GS into various formations. 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.

Commenter Name: Adam P. Haynes Letter ID: 0184

Commenter Organization: Texas Independent Producers and Royalty Owners

Association (TIPRO)

Comment ID:

22787

Other EPA Comment Codes and Descriptions: 3100 2.1 Proposed Geologic Siting Requirements

(40 CFR 146.83) 

Comment: An additional point of concern in the rules is the limited view of applicable 

storage sites. While brine aquifers may indeed be good candidates for geologic 

storage, the same is true of oil and gas reservoirs, both productive and nonproductive. The EPA should develop a site rating system that allows for the 

geologic storage of CO2 in stable subsurface formations. This type of rating 

system will ensure that sites which are best suited to handle large CO2 storage 

projects are utilized and any CCS regulatory system will have early successes. 

Of course, the most likely sites to score well in any ranking system would be 

formations containing or having contained hydrocarbon reserves and properly 

permitted Class II wells existing in these formations should be acceptable 

conduits for CCS. 

Response: EPA disagrees that a rating system is appropriate. Instead, the GS rule focuses on

evaluating the suitability of a site based on site-specific geological and operational data. EPA

believes that a detailed geological site characterization (required 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 framework developed to address specific risks to USDWs posed by

injection. The Class VI GS requirements are tailored so that they are appropriate for the unique

nature of injecting large volumes of CO2 into a variety of geological formations for long-term

storage. 

EPA agrees that depleted oil and gas fields are promising formations for GS, provided the Class VI

siting, well construction and operation, monitoring and testing, and post-injection site care and site

closure requirements are met. EPA adds that injection of carbon dioxide for the purposes of

enhanced oil recovery is classified as Class II injection, not Class VI, and will require a Class II

permit. Wells for which the primary purpose is long term sequestration are considered Class VI

wells.

EPA adds that the GS rule does not include criteria for rating particular sites for GS. EPA 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 to owners or operators regarding characterizing the regional geology and

hydrogeology of a proposed GS site as well as performing the necessary geochemical,

geomechanical, and geophysical 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.

31
Commenter Name: Edward Steadman Letter ID: 0220

Commenter Organization: The Energy and Environmental Research Center at the

University of North Dakota

Comment ID:

21594

Comment: Page 43502. H. What Are the Target Geologic Formations for GS of CO2? 

This section grossly misrepresents the types of geologic formations that are 

suitable for CO2 sequestration. It is irresponsible to discredit the meaningful 

role that depleting and/or depleted oil and gas reservoirs can play in 

sequestering CO2. While the document gives credit to the vast amount of 

geological information that is known about oil and gas reservoirs, it then 

implies that this knowledge does not overcome all of the perceived technical 

challenges associated with using oil and gas reservoirs for geologic storage. 

The techniques that would be used to alleviate the concerns listed in this 

section are less onerous than the proposed requirements to permit a Class VI 

injection well. Additionally, just as all deep saline formations may not be 

suitable for geologic storage, there may be oil and gas reservoirs that are not 

suitable as well. Prudent site selection should help determine suitable geologic 

settings, not broad statements declaring one geologic formation better than the 

other. 

Response: EPA agrees that depleted oil and gas fields are promising formations for GS. However,

EPA also believes that large-scale GS presents unique technical challenges, 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 geologic formations. For

this reason, EPA has finalized the tailored requirements in the GS rule.

The final GS rule does not preclude injection into any formation type, including oil and gas

reservoirs, provided owners or operators can demonstrate that GS can be performed in a manner that

protects USDWs from endangerment and that the Class VI siting, well construction and operation,

monitoring and testing, and post-injection site care and site closure requirements are met. 

EPA further clarifies that the GS rule is not intended to promote a preference for GS in any

particular formation type, to address use of resources, or to reduce costs associated with GS into

various formations. 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.

Commenter Name: Darrick Eugene Letter ID: 0223

Commenter Organization: Texas Carbon Capture and Storage Association Comment ID: 23959

Comment: Point #3: The draft rules focus on minimizing the number of wellbore penetrations 

at a geologic storage facility. The Preamble discusses "numerous artificial 

penetrations" related to oil and gas reservoirs.[FN4] The TxCCSA believes this focus 

is misplaced and damaging because it potentially eliminates certain target 

geologic formations and represents an unrealistic approach to geologic storage. 

In the first case, the best target geologic formations, typically producing or 

depleted oil and gas reservoirs, where geologic storage projects will be 

of dramatically lower risk, have numerous wellbore penetrations from previous 

exploration activity. Many of those formations have proven trapping conditions 

for substances lighter than brine and therefore very much like CO2. In addition, 

32
the previous exploration activity provides the understanding of the subsurface 

to guide geologic storage projects. To eliminate those areas based upon a 

postulated concern of leakage from preexisting wellbores is misplaced. From a 

geologic perspective, it is much easier to fix a leaky wellbore than a leaky 

fault. 

In the second case, this focus demonstrates a lack of understanding of the 

compartmentalization of natural reservoir systems. It will be inconceivable to 

expect a single well or even a single digit set of wells to accomplish geologic 

storage on a project of important size. An array of injection wells will be an 

imperative. Also, in the Cost Analysis section of the Preamble, the suggested 

4 See 73 Fed. Reg. at 43503. 

Response: EPA agrees that depleted oil and gas fields are promising formations for GS, provided the

Class VI siting, AoR and corrective action, well construction and operation, monitoring and testing,

and post-injection site care and site closure requirements are met under today’s rulemaking. 

EPA maintains that minimizing the number of artificial penetrations in a formation is imperative for

preventing endangerment of USDWs. For this reason, the GS rule requires owners or operators to

conduct an AoR study and address all deficient wells, as specified at §146.84. See the discussion of

AoR and corrective action in the preamble to the final rule for additional information.

EPA further clarifies that the GS rule is not intended to promote a preference for GS in any

particular formation type, to address use of resources, or to reduce costs associated with GS into

various formations. 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.

Commenter Name: Lori Wrotenbery Letter ID: 0247

Commenter Organization: Oklahoma Corporation Commission Comment ID: 22235

Comment: regulatory program. The division also supports efforts to develop a regulatory 

framework for long-term storage of carbon dioxide in depleted oil and gas 

reservoirs that not only protects underground sources of drinking water, but 

also prevents waste of oil and gas resources and protects the rights of mineral 

interest owners. 

Response: EPA agrees that depleted oil and gas fields are promising formations for GS, provided the

Class VI siting, AoR and corrective action, well construction and operation, monitoring and testing,

and post-injection site care and site closure requirements are met. The final GS rule does not

preclude injection into oil and gas fields provided owners or operators can demonstrate that GS can

be performed in a manner that protects USDWs from endangerment. 

EPA further clarifies that the GS rule is not intended to promote a preference for GS in any

particular formation type, to address use of resources, or to reduce costs associated with GS into

various formations. 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. Comments related to the protection of rights

of mineral interests are outside the scope of this rulemaking.

33
Commenter Name: Lori Wrotenbery Letter ID: 0247

Commenter Organization: Oklahoma Corporation Commission Comment ID: 22236

Comment: The division encourages EPA to continue to work with the various stakeholders to 

develop an appropriate regulatory framework for carbon dioxide storage in 

depleted oil and gas reservoirs. In developing this framework, EPA should use 

the existing Class II UIC regulatory program as a starting point and modify that 

program as necessary to address any risks uniquely associated with carbon 

dioxide storage operations. The resulting framework should be flexible enough to 

accommodate regional variations in geological structures and engineering 

parameters and incorporate the knowledge and experience of the state oil and gas 

agencies in regulating enhanced oil and gas recovery operations and natural gas 

storage operations. 

Response: EPA believes that building upon the existing UIC requirements (e.g., Class I well

requirements) to develop the Class VI GS regulation provides a foundation for protecting USDWs

based on success, field experience, and lessons learned about CO2 injection in other applications.

However, EPA also believes that large-scale GS presents unique technical challenges, 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 geologic

formations. For this reason, EPA has finalized the tailored requirements in the GS rule.

Commenter Name: Matt Toner Letter ID: 0506

Commenter Organization: Hydrogen Energy International Comment ID: 21186

Comment: Oil and gas reservoirs have proven capable of containing water buoyant fluids 

and gases for millions of years. 

These reservoirs are well-studied, and they offer the best opportunity to kick 

start large scale geologic storage of CO2 while building on 100 years of oil 

field operating experience. 

Response: EPA agrees that depleted oil and gas fields are promising formations for GS, provided the

Class VI siting, AoR and corrective action, well construction and operation, monitoring and testing,

and post-injection site care and site closure requirements are met. The final GS rule does not

preclude injection into oil and gas fields provided owners or operators can demonstrate that GS can

be performed in a manner that protects USDWs from endangerment.

Comment Code: 2146 1.6.2.2 Comments opposing injection into depleted reservoirs 

Individual Comments

Commenter Name: Michael H. Cochran Letter ID:

0108

Commenter Organization: Bureau of Water, Division of Environment, Kansas

Department of Health & Environment (KDHE)

Comment

ID: 21945

Other EPA Comment Codes and Descriptions: 2000 1.5 Need for a New Class of Injection Well;

2140 1.6.2 Depleted oil and gas reservoirs 

34
Comment: 5. Consider developing regulations that actually address an injection/withdrawal 

type project much similar to a natural gas porosity storage system. In this 

scenario the CO2 is contained in a limited, defined geologic trap and the system 

is designed to inject the CO2 or withdraw the CO2 as needed. 

Response: EPA clarifies that the GS rule addresses injection wells designed for long-term

sequestration of carbon dioxide; the Class VI designation and permit requirements are not applicable

to owners or operators that plan to withdraw carbon dioxide. 

The Agency believes that the nature and risks of CO2 injection for the primary purpose of long-term

storage poses unique risks that may endanger USDWs, and therefore has developed new Class VI

regulations to address these risks. Furthermore, the GS requirements adequately address these risks.

Commenter Name: Andy Horn Letter ID: 0196

Commenter Organization: Colorado Ground Water Association (CGWA) Comment ID: 23928

Comment: Issue 8. The risks associated with the presence of old wells in depleted oil 

and gas fields are not adequately addressed in the proposed regulation. 

The use of depleted petroleum reservoirs poses a significant problem. Depleted 

petroleum traps are generally the oldest oilfields and there are the problems of 

record keeping and are likely subject to outdated and inappropriate technologies 

during their development and the subsequent abandonment of the wells. Oil 

fields initially are characterized by pressures that are higher than depthequivalent water bearing zones. However, as the fields are developed, those 

excess pressures are relieved, and the field becomes hydrostatically pressured 

or even underpressured. The result is that as the field ages and the reservoir 

becomes under pressured, well construction and abandonment integrity become less 

and less critical 

Undertaking CO2 sequestration in a depleted oil or natural gas field reverses 

the process of depressurization in the reservoir. Pumping CO2 (or any fluid) 

increases the pressure of the reservoir substantially and every old production 

and exploration bore hole becomes a potential route of failure. Well and 

borehole abandonment configurations, even if fully compliant with requirements 

in place at the time of the abandonment, may not be capable of containing the 

pressures of the GS reservoir. Even if the reservoir is allowed to fill 

passively to the spill point, there will be excess pressure relative to 

formation hydrostatic pressures at the confining layer. The magnitude of the 

excess pressure will be directly proportional to the density contrast with the 

formation brine and the thickness of the CO2 lens. Wells appropriately sealed 

against hydrostatic pressures present in the depleted oil field may fail 

catastrophically when subjected to pressures that result from CO2 storage in the 

trap. Here too, the rule needs to add specificity to what needs be performed in 

the way of finding and recompleting the abandonment of all pre-existing wells 

and boreholes to configurations consistent with the reservoir conditions 

expected after CO2 sequestration, not the conditions that exist at the time the 

field was abandoned or the project is initiated. There is no discussion in the 

USEPA materials supporting this rule that acknowledges or discusses the 

implications of the equivalent of an oil-field blow out. The catastrophic 

failure of a plugged or abandoned well would create an open conduit for the 

35
expulsion of supercritical CO2 to the ground surface, potentially miles from any 

injection infrastructure. 

Response: EPA believes that many depleted oil and gas reservoirs may be candidate formations for

GS, as the trapping mechanisms responsible for accumulation of the oil and gas are analogous to the

processes that will trap CO2 in the subsurface during GS. However, EPA acknowledges commenters'

concerns regarding GS in oil and gas reservoirs –including concerns about the use of older well

construction technologies. EPA clarifies that §146.84 requires the owner or operator to identify all

wells in the AoR and demonstrate to the Director's satisfaction that they are appropriately plugged

and will not serve as conduits for fluid movement. While this requirement allows the owner or

operator to rely on publicly available data, the Director has discretion to require additional research

if he/she has reason to believe that existing databases are incomplete or out of date. 

The Agency clarifies that the final GS rule contains additional requirements at §144.19 that address

the commenters' concerns and clarify the transition from Class II enhanced oil and gas recovery to

GS. Furthermore, the Agency clarifies that an owner or operator of a Class II well that is to be repermitted as a Class VI well must meet the grandfathering requirements at §146.81, the permit

application requirements at §146.82, and all operational, monitoring, and post-injection site care and

site closure requirements in Subpart H of Part 146. 

In response to the comment about subsurface depressurization, EPA acknowledges that there are

differences between CO2 injection for ER (where oil production serves to depressurize the reservoir)

and GS (where pressures will tend to increase, since no extraction occurs). It is for this reason that

CO2 injection for the purpose of long-term storage may not be regulated as Class II wells and

owners or operators of Class II wells whose primary purpose is long-term storage are subject to

Class VI, GS requirements, including those for rigorous site characterization at §146.82, well

construction at §146.86, and monitoring at §146.90. 

EPA acknowledges that there may be risks associated with GS into certain formation types. For this

reason, the Agency is using an adaptive approach to regulate GS injection. EPA will collect and

review project data on early GS projects, including those that inject into various formation types, to

determine whether the appropriate amount and types of information and documentation are being

collected. 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 appropriate or necessary.

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 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 can be found on EPA’s website at

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm.

Commenter Name: George Peridas Letter ID: 0291

Commenter Organization: Natural Resources Defense Council Comment ID: 25286

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 Class VI (seeking comment) 

Comment: Second, we highlight that the final rule needs to cater for GS in hydrocarbon 

reservoirs as well, and not just saline formations as proposed. Hydrocarbon 

36
reservoirs are likely to be among the first ones to be used for GS, and they 

need to be regulated appropriately. We do not believe that automatic delegation 

to Class II "as long as any production is occurring" is suitable. Under the 

economic driver of carbon constraints, additional risks might be posed in these 

reservoirs if operators inject larger volumes or at higher rates and pressures 

than they have been doing to date under Class II. Moreover, site 

characterization, operation, monitoring and closure requirements over and above 

the existing Class II will be needed to certify and assure "geologic 

sequestration" of injected carbon dioxide in hydrocarbon reservoirs. 

Response: EPA clarifies that the final rule is designed to address all types of formations in which

GS could take place. All applicants for GS wells must demonstrate that the proposed injection zone

is suitable for receiving carbon dioxide and that the confining zone can contain the injected carbon

dioxide and any displaced formation fluids. 

EPA believes that large-scale GS presents unique technical challenges, 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 geologic formations. For

this reason, EPA has finalized the tailored requirements in the GS rule.

EPA further clarifies that the GS rule is not intended to promote a preference for GS in any

particular formation type, to address use of resources, or to reduce costs associated with GS into

various formations. 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.

EPA clarifies that owners and operators of traditional EOR projects are subject to limits on injection

established under their Class II permits. If they exceed those limits, they will be considered to be in

violation of their Class II permit. EPA further clarifies that wells injecting into oil and gas formations

for the primary purpose of long-term containment of carbon dioxide are subject to the site

characterization, operation, monitoring, and closure requirements for Class VI wells in Subpart H of

40 CFR 146. For more information, please see the discussion on transition of Class II wells in the

preamble to the final GS rule.

Commenter Name: George Peridas Letter ID: 0291

Commenter Organization: Natural Resources Defense Council Comment ID: 25288

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 Class VI (seeking comment) 

Comment: • EPA must promulgate appropriate requirements for GS in hydrocarbon reservoirs 

in the current rulemaking. The mere continuation of hydrocarbon production in 

those fields is not a valid criterion for well classification; 

Response: As described above, the final GS rule does not preclude injection into any non-USDW

formation type, including hydrocarbon reservoirs, provided owners or operators can demonstrate that

GS can be performed in a manner that protects USDWs from endangerment. 

EPA 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 protected from endangerment. The

GS rule contains tailored requirements for the permitting, geologic site characterization, AoR and

corrective action, well construction, operation, mechanical integrity testing, monitoring, well

37
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.

Comment Code: 2160 1.6.3 Unmineable coal seams 

Individual Comments

Commenter Name: John Hanger Letter ID: 0130

Commenter Organization: Pennsylvania Dept. of Env. Protection Comment ID: 21517

Comment: Target Geologic Formations for Geologic Sequestration of CO2 

-EPA states in their documents (examples: pages 43502 to 43503 and 43512) that 

there are coal formations too deep to ever be mined. This is not true in 

Pennsylvania. All coal formations in Pennsylvania are at depths that are 

technologically capable of being mined. Economics will dictate whether or not 

these deeper coal formations will be mined. 

Response: EPA acknowledges the comment, and clarifies that the use of coal mines for anything

other than GS is outside the scope of the GS rulemaking.

Commenter Name: Michael Mudd Letter ID: 0167

Commenter Organization: FutureGen Alliance (FGIA) Comment ID: 22462

Comment: Unmineable Coal Seams p. 43503, c.2) 

While coal seams are well studied and understood, the process of CO2 adsorption 

to coal has not been proven and the chemical reaction of supercritical CO2 with 

coal formations are not well understood. 

Comment: This statement is contentious and does not add to the substance of the 

Propose Rule. In fact, the process of CO2 absorption is well understood. 

Suggest removing the statement. 

In addition, many ECBM recovery operations will likely be shallow. Shallow 

storage will result in the CO2 remaining in a gaseous state, which can limit the 

amount of CO2 that can be sequestered. 

Comment: These statements are not true. The statements would be true for 

storage into shallow aquifer pore space, such as in shallow saline formations, 

but it is not the case for storage into shallow coal seams. In shallow coal 

seams CO2 is absorbed and remains in the condensed phase and not in the gaseous 

state. Suggest removing the statement. 

EPA is concerned that coal seams in the close proximity to USDWs and CO2 

injection for GS could endanger USDWs. In some cases, coal seams are considered 

USDWs and may serve as public drinking water supplies. As a result, EPA is 

proposing to preclude the injection of CO2 for long-term storage into coal seams 

where they are above the lowermost USDW. 

38
Comment: See comments above under the heading Stratigraphic Restriction of GS to 

Below Lowermost USDW. 

Response: EPA acknowledges that site-suitability for GS is dependent on a number of factors and

that many formation types may be suitable for GS. EPA agrees that GS into unmineable coal seams

has the potential to allow sequestration while ensuring USDW protection from endangerment, as

described by commenters citing the process of enhanced methane recovery. The final GS rule does

not preclude injection into unmineable coal seams provided owners or operators can demonstrate that

GS can be performed in a manner that protects USDWs from endangerment. The Agency clarifies

that owners or operators of Class VI wells used for injecting CO2 into unmineable coal seams are

subject to the same site characterization, well construction, operation, monitoring, post-injection site

care and site closure requirements that are required of projects injecting into other formation types. 

EPA clarifies that the final rule requires that injection 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.

Commenter Name: Frederick R. Eames Letter ID: 0178

Commenter Organization: CCS Alliance Comment ID: 23850

Comment: EPA states that "[w]hile coal seams are well studied and understood, the process 

of CO2 adsorption to coal has not been proven."[FN48] The Alliance believes it 

is well understood. EPA also states that "many ECBM recovery operations will 

likely be shallow. Shallow storage will result in the CO2 remaining in a gaseous 

state..."[FN49] Some parties believe this is incorrect, and that such a 

statement would be true for storage into shallow aquifer pore space, such as in 

shallow saline formations, but that it is not true for storage into shallow coal 

seams. In that case, the CO2 is adsorbed and remains in the dense phase. 

[FN48] Proposed Rule, 73 Fed. Reg, at p. 43503. 

[FN49] Id. 

Response: EPA acknowledges that site-suitability 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 other formation type, provided owners or operators can demonstrate

that GS can be performed in a manner that protects USDWs from endangerment based on the

requirements provided in the GS rulemaking. The Agency anticipates that in the near-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). EPA will continue to review data on early GS projects, including those in

unmineable coal seams, to determine whether the appropriate amount and types of information and

documentation are required and being collected. 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 appropriate or necessary.

EPA recognizes that GS in unmineable coal seams has been the subject of less research than saline

39
formations or depleted oil and gas reservoirs. However, EPA has examined select field projects

involving injection into unmineable coal seams, including the Pump Canyon Site, near Archuleta,

New Mexico. In the Notice of Data Availability and Request for Comment, EPA described research

at the Pump Canyon site where the Southwest Partnership is studying CO2 injection into deep,

unmineable coal seams and performing a "seal analysis" of the ability of the Kirtland Formation to

act as a barrier to the movement of CO2 or other reservoir fluids. EPA continues to follow this

project, recently completed projects, and ongoing GS projects injecting into unmineable coal seams.

Other coal seam injection projects are underway through the RCSPs in the Illinois Basin, Black

Warrior Basin, and Central Appalachian Basin.

Commenter Name: Kurt Waltzer Letter ID: 0250

Commenter Organization: Clean Air Task Force Comment ID: 22296

Other EPA Comment Codes and Descriptions: 2200 1.6.4 Other formation types 

Comment: The rule should explicitly exclude from Class VI efforts to sequester CO2 in 

basalts, coal seams, salt caverns and shales, which instead should be regulated 

under Class V Experimental 

We believe that EPA has ample basis for adopting rules to regulate geologic 

sequestration in hydrocarbon reservoirs and in deep brine formations. For these 

types of geologic formations, there is a widespread technical consensus on how 

to assess and manage risks, what data is needed to characterize sites, how to 

select sites, how to conduct injection operations, how to model the behavior of 

CO2 in the reservoir, and how to monitor project performance. There is no such 

consensus, however, regarding sequestration in basalts, coal seams, salt caverns 

and shales. The trapping mechanisms of CO2 and/or the operational engineering 

involved in such operations is significantly different to those in deep saline 

formations and hydrocarbon reservoirs, and using identical regulatory language 

would be ill advised. In fact, it is not known at this time whether 

sequestration (or even injection in some cases) can even be done at scale in 

such formations - efforts in these formations are very much still in the 

experimental stage. There is no basis at this time for determining whether rules 

that are appropriate for wells in hydrocarbon reservoirs and deep saline 

formations are also appropriate for wells in these other formations. Until there 

is better understanding of whether and how sequestration can be safely 

accomplished in basalts, coal seams, salt caverns and shales, wells in these 

formations should be treated as experimental wells under Class V. 

Projects designed to evaluate injection in coal seams, salt caverns and shales 

should be permitted under the UIC Class V provisions and subject to the March 

2007 Guidance on "Using the Class V Experimental Technology Well Classification 

for Pilot GS Projects. [FN20] This Guidance clearly states that Class V is 

intended only for projects "...designed to evaluate the technical issues 

associated with CO2 injection" [FN21]. The Director should review all Class V GS 

permit applications to insure that they meet the definition of Pilot Project in 

CFR 146.3: "... a technology which has not proven feasible under the conditions 

in which it is being tested." The purpose of such pilot projects should be to 

gather and share information which will lead to a clearer understanding of the 

feasibility of such projects on a commercial scale. 

40
[FN20: UICPG#83] 

[FN21: Id. at p. 1] 

In order to implement our suggestion regarding these formations, we recommend 

revising sections 144.6(f), 144.80(f), 146.5(f) and the definition of 

sequestration in §146.81 accordingly. We suggest retaining the provision in 

proposed §144.15 that the construction, operation or maintenance of any nonexperimental Class V geologic sequestration well is prohibited. 

Response: EPA acknowledges that site-suitability 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

any formation type provided owners or operators can demonstrate that GS can be performed in a

manner that protects USDWs from endangerment. The Agency acknowledges that GS into basalts,

coal seams, salt domes, shales, limestone formations, and fractured karst will likely have limited

application, or that owners or operators seeking Class VI permits for injection into these formations

may not be able to meet the final GS requirements or demonstrate protection of USDWs. 

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into

basalts, which have been the subject of limited experimental projects in the past. EPA anticipates

that in the short-term, GS into basalts, coal seams, salt domes, shales, limestone formations, and

fractured karst will continue to be experimental in nature (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 will continue to review data on early GS projects, including

those in such formations, to determine whether the appropriate amount and types of information and

documentation are required and being collected. 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 appropriate or necessary.

Commenter Name: Walter L. Baker Letter ID: 0253

Commenter Organization: Utah Division of Water Quality Comment ID: 22344

Other EPA Comment Codes and Descriptions: 2200 1.6.4 Other formation types 

Comment: PROHIBITIONS - COAL SEAMS, BASALTS, SALT DOMES, SHALES, OTHER

FORMATIONS, 

We do not support the categorical prohibition of CO2 geologic sequestration in 

coal seams, basalts, salt domes, shales or any other formation. EPA states in 

the preamble to the proposed rule that "[t]hese formations are limited in 

geographic and geologic distribution throughout the U.S., and their 

technological or economic viability as GS [geologic sequestration] sites have 

not been demonstrated." For this very reason, these formations should not be 

eliminated as possible sequestration reservoirs. Ongoing demonstration projects 

conducted under the Department of Energy may yet demonstrate their viability. 

Response: 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

41
post-injection site 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

satisfaction that GS in coal seams, basalts, salt domes, or shales can be accomplished 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. 

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into

formations such as coal seams, basalts, salt domes, or shales, which have been the subject of limited

experimental projects in the past. For this reason, the Agency is using an adaptive approach to

regulate GS injection. EPA will collect and review project data on early GS projects, including those

that inject into various formation types, to determine whether the appropriate amount and types of

information and documentation are being collected. 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 appropriate or necessary.

Comment Code: 2163 1.6.3.1 Comments in favor of injection into unmineable coal seams 

Individual Comments

Commenter Name: Sandi Tabor Letter ID: 0162

Commenter Organization: Lignite Energy Council (LEC) Comment ID: 21300

Comment: 2.Target Geologic Formations for GS of CO2 •• Unmineable coal seams -EPA should 

not arbitrarily preclude injection of C02 into certain formations; rather EPA 

should conduct a site-specific review of the appropriateness of the geology to 

determine suitability for GS. More specifically, the storage of C02 in 

unmineable (as opposed to mined out) coal seams is an area of very active 

research in our region. PCOR is currently conducting a pilot test of this 

concept in Burke County, North Dakota. Other DOE Partnerships are conducting 

similar (non-lignite) coal seam sequestration field tests. PCOR conservatively 

estimates more than 10 billion tons of potential storage in regional coal seams 

that if utilized could result in the incremental production of more than 17 Tef 

of coal bed methane, which would provide positive economic feedback to a CCS 

project. We urge EPA to develop regulations in this area in consultation with 

the DOE Partnerships and based on the outcome of their research. 

Response: The final GS rule does not preclude injection into any non-USDW formation type,

including coal seams, provided owners or operators can demonstrate that GS can be performed in a

manner that protects USDWs from endangerment. EPA recognizes that research on the feasibility of

various types of geologic formations is underway, and it continues to track the progress of this

research. For example, while developing the GS regulation, EPA evaluated projects conducted by the

seven regional carbon sequestration partnerships funded by the U.S. Department of Energy and

coordinated through the National Energy Technology Laboratory (NETL), as well as several

international projects. In addition, DOE's RCSPs are conducting numerous pilot projects that inject

CO2 into a variety of formation types, including saline, basalt, coal seams, and oil and gas

reservoirs. 

42
EPA acknowledges that there may be risks associated with GS into certain formation types. For this

reason, the Agency is using an adaptive approach to regulate GS injection. EPA will collect and

review project data on early GS projects, including those that inject into various formation types, to

determine whether the appropriate amount and types of information and documentation are being

collected. 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 appropriate or necessary.

EPA further clarifies that the GS rule is not intended to promote a preference for GS in any

particular formation type, to address use of resources, or to reduce costs associated with GS into

various formations. 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.

Additionally, EPA coordinated with Federal, including DOE, and non- Federal entities on GS and

CCS to determine how best to tailor existing injection requirements to CO2 for GS.

Commenter Name: James Stine Letter ID: 0163

Commenter Organization: National Rural Electric Cooperative Association

(NRECA)

Comment ID:

21324

Other EPA Comment Codes and Descriptions: 2200 1.6.4 Other formation types 

Comment: 3. NRECA believes that the Final Rule should not contain a blanket prohibition 

on injection of CO2 into coal seams (whether above or below the lowermost USDW) 

or into other formations such as basalts, salt domes, or shales. 73 Fed. Reg. at 

43503. If it can be demonstrated that the injection of CO2 into such sites is 

protective of USDWs, then such activities should remain available options under 

the Class VI UIC program. 

Response: The final GS rule does not preclude injection into any non-USDW formations, including

coal seams, provided the site-suitability requirements in the GS rule are met, and owners or

operators can demonstrate that GS can be performed in a manner that protects USDWs from

endangerment. 

EPA acknowledges that there are unknowns regarding GS into formations such as coal seams, which

have been the subject of limited experimental projects in the past. For this reason, the Agency is

using an adaptive approach to regulate GS injection. EPA will collect and review project data on

early GS projects, including those that inject into various formation types, to determine whether the

appropriate amount and types of information and documentation are being collected. 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 appropriate or necessary.

EPA clarifies that the final rule requires that injection 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.

Commenter Name: Pamela Faggert Letter ID: 0175

Commenter Organization: Dominion Comment ID: 23522

Comment: d. Sequestration in Unmineable Coal Seams 

43
The proposed rule prematurely concludes that "There are a number of technical 

challenges related to use of coal seams for GS.... [and] as a result, EPA is 

proposing to preclude the injection of CO2 for long-term storage into coal seams 

where they are above the lowermost USDW". 

According to the attached white paper (Footnote l) by the Director of the 

Virginia Center for Coal and Energy Research at Virginia Polytechnic and State 

University (VCCER), Dr. Michael Karmis, et al. [SEE EPA-HQ-OW-2008-0390-0175.PDF 

FOR THIS DOCUMENT], there is ample evidence that coal seams are a viable 

formation into which CO2 can be economically, safely and securely sequestered 

with many tangible advantages over saline aquifers and other major geologic 

sinks. In contrast to storage in deep saline aquifers, CO2 in coal seams clings 

to the molecular structure of coal by the process of adsorption, which minimizes 

the mobility and thus risk of leakage. Furthermore, coal can hold large 

quantities of gas at pressures less than 500 psi, which significantly helps 

minimize the cost of compression during injection operations. 

Moreover, in many coal basins, where many CO2 emitters are located, viable 

saline aquifers and oil reservoirs are not present and coal is the only viable 

medium for CO2 storage. The extensive existing infrastructure should be 

recognized as a resource for early investments in sequestration. 

The estimated capacity of coal seams identified in the DOE "Carbon Sequestration 

Atlas of the United States and Canada", though only a fraction of that of other 

formations, represents over 22 years of total US CO2 emissions. 

Accordingly, coal seams above the lowermost USDW should not be summarily 

dismissed as a viable injection formation, provided it can be shown that 

a project is sufficiently protective of USDW. 

Footnote 1: Michael Karmis, VA Tech; Nino Ripepi, VA Tech; and Jack Pashin, 

Geologic Survey ofAlabama, "The Case for Carbon Sequestration in Coal Seams", 

December, 2008. 

Response: EPA acknowledges that site-suitability for GS is dependent on a number of factors and

that many formation types may be suitable for GS. EPA agrees that GS into unmineable coal seams

has the potential to allow sequestration while ensuring USDW protection from endangerment, as

described by commenters citing the process of enhanced methane recovery. The final GS rule does

not preclude injection into unmineable coal seams provided owners or operators can demonstrate that

GS can be performed in a manner that protects USDWs from endangerment. The Agency clarifies

that owners or operators of Class VI wells used for injecting CO2 into unmineable coal seams are

subject to the same site characterization, well construction, operation, monitoring, post-injection site

care and site closure requirements that are required of projects injecting into other formation types. 

EPA clarifies that the final rule requires that injection 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.

44
Commenter Name: Bradley J. Field Letter ID: 0186

Commenter Organization: New York State Dept. of Environmental Conservation

Div. of Mineral Resources

Comment ID:

25177

Other EPA Comment Codes and Descriptions: 4324 2.4.4.1.2 Comments opposed to requiring

injection below the lowermost USDW 

Comment: G. As with unmineable coal seams, EPA seeks comment on prohibiting injection 

into such formations if they are above the lowermost USDW. 

NYSDEC-DMN Response: While not a likelihood in New York due to the absence of 

coal in the state and typical depths to lowermost USDWs, NYSDEC-DMN believes 

there should not be any blanket prohibition against injection into any 

potentially approvable geologic zone even if it is above the lowermost USDW. 

There may be circumstances where this is appropriate and safe. The decision to 

permit a project should be made on a site-specific basis and evaluation. 

Response: EPA agrees that GS into unmineable coal seams has the potential to allow sequestration

while ensuring USDW protection from endangerment, as described by commenters citing the process

of enhanced methane recovery. The final GS rule does not preclude injection into unmineable coal

seams provided owners or operators can demonstrate that GS can be performed in a manner that

protects USDWs from endangerment. The Agency clarifies that owners or operators of Class VI

wells used for injecting CO2 into unmineable coal seams are subject to the same site

characterization, well construction, operation, monitoring, post-injection site care and site closure

requirements that are required of projects injecting into other formation types. 

EPA clarifies that the final rule requires that injection 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.

Commenter Name: Paul Pike Letter ID: 0198

Commenter Organization: Ameren Corporation Comment ID: 23943

Other EPA Comment Codes and Descriptions: 2200 1.6.4 Other formation types 

Comment: SITING 

Ameren understands that EPA must consider the potential impact of CO2 GS 

projects on USDWs and other pre-existing subsurface activities (e.g., natural 

gas storage operations). However, we believe that at this point, the imposition 

of prohibition on certain sites will limit the benefits of this program. The 

important criteria is protecting USDWs and meeting other applicable conditions 

for Class VI CO2 GS wells. As stated earlier, CO2 GS is still being developed 

for commercial scale use and methods may be developed to address all issues that 

would otherwise result in impacts on other subsurface activities. This means 

that there should not be a prohibition on injection of CO2 into coal seams 

(whether above or below the lowermost USDW) or into other formations such as 

basalts, salt domes, or shales. 73 Fed. Reg. at 43503. 

Response: EPA agrees that GS into unmineable coal seams has the potential to allow sequestration

while ensuring USDW protection from endangerment, as described by commenters citing the process

of enhanced methane recovery. The final GS rule does not preclude injection into unmineable coal

45
seams, or into basalts, salt domes, or shales, provided owners or operators can demonstrate that GS

can be performed in a manner that protects USDWs from endangerment. The Agency clarifies that

owners or operators of Class VI wells used for injecting CO2 into these formation types are subject

to the same site characterization, well construction, operation, monitoring, post-injection site care

and site closure requirements that are required of projects injecting into other formation types. 

EPA acknowledges that there are unknowns associated with GS, particularly regarding GS into

formations such as coal seams, basalts, salt domes, or shales, which have been the subject of limited

experimental projects in the past. For this reason, the Agency is using an adaptive approach to

regulate GS injection. EPA will collect and review project data on early GS projects, including those

that inject into various formation types, to determine whether the appropriate amount and types of

information and documentation are being collected. 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 appropriate or necessary.

EPA clarifies that the final rule requires that injection 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.

Commenter Name: Chris M. Hobson Letter ID: 0201

Commenter Organization: Southern Company Comment ID: 22163

Other EPA Comment Codes and Descriptions: 2200 1.6.4 Other formation types 

Comment: The same logic argues against blanket prohibitions on injection in coal seams or 

other formations such as basalts, salt domes, or shales: if a scientific and 

technical demonstration can be made showing that the injection of CO2 into one 

of these formations will be protective of USDWs, then that formation should 

remain an available option under the Class VI UIC Program. See id. at 43503. 

Response: The final GS rule does not preclude injection into any non-USDW formations, such as

basalts, salt domes, or shales, provided the site-suitability requirements in the GS rule are met, and

owners or operators can demonstrate that GS can be performed in a manner that protects USDWs

from endangerment. 

EPA acknowledges that there are unknowns associated with GS, particularly regarding GS into

formations such as coal seams, basalts, salt domes, or shales, which have been the subject of limited

experimental projects in the past. For this reason, the Agency is using an adaptive approach to

regulate GS injection. EPA will collect and review project data on early GS projects, including those

that inject into various formation types, to determine whether the appropriate amount and types of

information and documentation are being collected. 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 appropriate or necessary.

EPA clarifies that the final rule requires that injection 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.

46
Commenter Name: Christopher Murray Letter ID: 0207

Commenter Organization: Pacific Northwest National Laboratory Comment ID: 22452

Comment: - No blanket prohibition should be introduced for any potential non-saline 

reservoir; promising GS targets of basalt, unmineable coal seams, etc., should 

be evaluated with methodologies similar to those for saline formations. 

Response: EPA clarifies that the GS rule does not preclude injection into any non-USDWs

formations, provided the site-suitability requirements in the GS rule are met. EPA acknowledges that

there may be risks associated with GS into certain formation types. For this reason, the Agency is

using an adaptive approach to regulate GS injection. EPA will collect and review project data on

early GS projects, including those that inject into various formation types, to determine whether the

appropriate amount and types of information and documentation are being collected. 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 appropriate or necessary.

Commenter Name: Barbara Walz Letter ID: 0216

Commenter Organization: Tri-State Generation and Transmission Association,

Inc.

Comment ID:

22971

Comment: geologic sequestration wells. The final rule should not contain a blanket 

prohibition on injection of CO2 into coal seams or into other formations such as 

basalts, salt domes, or shales. The final rule must be flexible enough to 

accommodate developments in information and technology related to carbon 

sequestration. 

Response: EPA clarifies that the GS rule does not preclude injection into any non-USDWs

formations, provided the site-suitability requirements in the GS rule are met. EPA acknowledges that

there may be risks associated with GS into certain formation types. For this reason, the Agency is

using an adaptive approach to regulate GS injection. EPA will collect and review project data on

early GS projects, including those that inject into various formation types, to determine whether the

appropriate amount and types of information and documentation are being collected. 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 appropriate or necessary.

Commenter Name: Edward Steadman Letter ID: 0220

Commenter Organization: The Energy and Environmental Research Center at the

University of North Dakota

Comment ID:

21595

Comment: CO2 storage in coal seams is an area of very active research. DOE Partnerships 

are conducting pilot-scale coal seam sequestration field tests. Utilizing coal 

seams at shallow depths would require less compression (gas phase vs. 

supercritical CO2), reduce drilling costs, may allow for greater concentrations 

of inert nitrogen (which could reduce capture costs), and be proximal to many 

minemouth operations. Ruling out such storage by administrative fiat is 

premature. The results of ongoing research need to be considered prior to such 

proposed actions. 

47
Response: 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 performed in a

manner that protects USDWs from endangerment as required under the GS final rulemaking. The

Agency anticipates that in the near-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). EPA will continue to

review data on early GS projects, including those in unmineable coal seams, to determine whether

the appropriate amount and types of information and documentation are required and being

collected. 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 appropriate or necessary.

EPA recognizes that GS in unmineable coal seams has been the subject of less research than saline

formations or depleted oil and gas reservoirs. However, EPA has examined select field projects

involving injection into unmineable coal seams, including the Pump Canyon Site, near Archuleta,

New Mexico. In the Notice of Data Availability and Request for Comment, EPA described research

at the Pump Canyon site where the Southwest Partnership is studying CO2 injection into deep,

unmineable coal seams and performing a "seal analysis" of the ability of the Kirtland Formation to

act as a barrier to the movement of CO2 or other reservoir fluids. EPA continues to follow this

project, recently completed projects, and ongoing GS projects injecting into unmineable coal seams.

Other coal seam injection projects are underway through the RCSPs in the Illinois Basin, Black

Warrior Basin, and Central Appalachian Basin.

Commenter Name: Mark Bohrer Letter ID: 0241

Commenter Organization: North Dakota Industrial Commission Comment ID: 23226

Other EPA Comment Codes and Descriptions: 4430 2.4.4.3.3 Injection into coal seams above

USDWs (seeking comment) 

Comment: 5. EPA is proposing to preclude the injection of CO2 for long-term storage into 

coal seams where they are above the lowermost USDW. EPA requests comment on 

this proposed prohibition. EPA Notice 43503. 

This arbitrary exclusion would eliminate a vast number of potential 

sequestration zones. Enhanced recovery operations above the lowermost USDW have 

been taking place for a very long time. Unmineable coals in North Dakota are 

found in high clay content glacial till which, if unfractured, serves as an 

excellent confining zone. Based upon carbon dioxide’s affinity to adhere to 

coals, it is unwise to arbitrarily eliminate a potentially large number of 

sequestration zones. Exclusion of these zones even in areas where other 

abundant supplies of freshwater are available may severely limit sequestration 

options. These situations are best handled locally where all of the pertinent 

regional geologic factors can be considered. 

Response: EPA acknowledges that site-suitability 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 performed in a manner that protects USDWs from endangerment based on requirements

under today’s rulemaking. The Agency anticipates that in the near-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).

48
EPA will continue to review data on early GS projects, including those in unmineable coal seams, to

determine whether the appropriate amount and types of information and documentation are required

and being collected. 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 appropriate or

necessary.

EPA recognizes that GS in unmineable coal seams has been the subject of less research than saline

formations or depleted oil and gas reservoirs. However, EPA has examined select field projects

involving injection into unmineable coal seams, including the Pump Canyon Site, near Archuleta,

New Mexico. In the Notice of Data Availability and Request for Comment, EPA described research

at the Pump Canyon site where the Southwest Partnership is studying CO2 injection into deep,

unmineable coal seams and performing a "seal analysis" of the ability of the Kirtland Formation to

act as a barrier to the movement of CO2 or other reservoir fluids. EPA continues to follow this

project, recently completed projects, and ongoing GS projects injecting into unmineable coal seams.

Other coal seam injection projects are underway through the RCSPs in the Illinois Basin, Black

Warrior Basin, and Central Appalachian Basin.

EPA clarifies that the final rule requires that injection 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.

Commenter Name: Kevin Frederick Letter ID: 0525

Commenter Organization: Wyoming Department of Environmental Quality Comment ID: 21404

Other EPA Comment Codes and Descriptions: 4344 2.4.4.2.2 Comments opposed to setting a

minimum injection depth 

Comment: Given the variety of sub-surface geologic conditions that exist both within and 

between states, we would not support setting a minimum injection depth 

requirement for CO2 geologic sequestration in lieu of requiring that such 

injection take place below the lower most USDW. 

We do not support prohibiting the injection of CO2 for long term storage into 

certain formations where they are above the lowermost USDW. As mentioned before, 

we believe there are likely circumstances where injection into formations 

including deep or mineable coal seams situated above the lower most USDW may be 

practical and protective of overlying and underlying USDW's. 

Response: EPA clarifies that the GS rule does not preclude injection into any non-USDWs

formations, including coal seams, provided the site-suitability requirements in the GS rule are met.

EPA acknowledges that there may be risks associated with GS into certain formation types. For this

reason, the Agency is using an adaptive approach to regulate GS injection. EPA will collect and

review project data on early GS projects, including those that inject into various formation types, to

determine whether the appropriate amount and types of information and documentation are being

collected. 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 appropriate or necessary.

EPA agrees that it is not appropriate to set a minimum injection depth for GS projects and the

49
Agency believes that a determination of site-suitability for GS (i.e., that subsurface formations will

receive and confine injected CO2) should be made on a site-specific basis. The GS rule, at §146.82,

requires the owner or operator to provide extensive site- and project-specific information to the

Director to demonstrate that the site meets the minimum site criteria at §146.83, that the CO2 will be

contained within the injection formation, and that USDWs will be protected from endangerment.

EPA acknowledges that there are limited circumstances where injection above the lowermost USDW

can be performed in a manner that protects USDWs, as long as appropriate protections are in place.

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 injection into non-USDW formations above and/or

between USDWs. The waiver approach requires the submission of extensive, site-specific

information (in conjunction 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 USDWs. The requirements are designed to ensure that the owner or operator, the Director, and the

Regional Administrator consider, on a site specific basis, the implications, benefits, and challenges

associated with GS and ensuring water availability and USDW protection. 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 Code: 2166 1.6.3.2 Comments opposing injection into unmineable coal seams 

Individual Comments

Commenter Name: Thomas Curtis Letter ID: 0181

Commenter Organization: American Water Works Association (AWWA) Comment ID: 23678

Other EPA Comment Codes and Descriptions: 4322 2.4.4.1.1 Comments in favor of requiring

injection below the lowermost USDW 

Comment: Category: USDW Location 

EPA Request for Comment: EPA is proposing to preclude the injection of CO2 for 

long-term storage into coal seams where they are above the lowermost USDW. EPA 

requests comment on this proposed prohibition. EPA Notice 43503. 

AWWA Response: AWWA recommends that EPA preclude the injection of carbon dioxide 

into coal seams located above the lowermost USDWs. First and foremost, AWWA is 

adamantly opposed to the injection of carbon dioxide into any storage formation 

not located beneath the lowermost USDW. If a utility ever desired to use the 

USDW as a water resource, they would have to drill through the carbon dioxide 

plume, thus creating a pathway for carbon dioxide to potentially migrate out of 

the confining layer and into nearby aquifers. This could cause contamination of 

USDWs located above the coal seam, and result in significant remediation 

activities for a water utility. Second, little research has been conducted to 

determine the specific impacts that storage of carbon dioxide would have on coal 

seams. Much of the research that has been performed to date has been on either 

carbon dioxide storage in saline reservoirs or in depleted oil/gas fields. AWWA 

recommends that at this point in time, EPA preclude the injection of carbon 

dioxide into all coal seams, no matter where they are located in the subsurface. 

50
This regulation was not designed for coal seams to be used as carbon dioxide 

storage reservoirs. Therefore, AWWA recommends that any wells constructed for 

the injection of carbon dioxide into coal seams wells be permitted under the 

Class V experimental wells until the potential impacts of coal seam carbon 

dioxide sequestration on USDWs are better understood. 

Response: The final GS rule does not preclude injection into unmineable coal seams (or any nonUSDW formation type) provided owners or operators can demonstrate that GS can be performed in

a manner that protects USDWs from endangerment as required under today’s final rule. 

EPA recognizes that GS in unmineable coal seams has been the subject of less research than saline

formations or depleted oil and gas reservoirs. However, EPA has examined select field projects

involving injection into unmineable coal seams, including the Pump Canyon Site, near Archuleta,

New Mexico. In the Notice of Data Availability and Request for Comment, EPA described research

at the Pump Canyon site where the Southwest Partnership is studying CO2 injection into deep,

unmineable coal seams and performing a "seal analysis" of the ability of the Kirtland Formation to

act as a barrier to the movement of CO2 or other reservoir fluids. EPA continues to follow this

project, recently completed projects, and ongoing GS projects injecting into unmineable coal seams.

Other coal seam injection projects are underway through the RCSPs in the Illinois Basin, Black

Warrior Basin, and Central Appalachian Basin.

EPA acknowledges that there may be risks associated with GS into coal seams. For this reason, the

Agency is using an adaptive approach to regulate GS injection. The Agency anticipates that in the

near-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).EPA will collect and review project data on early GS projects,

including those that inject into various formation types, to determine whether the appropriate amount

and types of information and documentation are being collected. 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 appropriate or necessary.

EPA clarifies that the final rule requires that injection 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.

Commenter Name: Diane VanDe Hei Letter ID: 0213

Commenter Organization: Association of Metropolitan Water Agencies

(AMWA)

Comment ID:

22941

Other EPA Comment Codes and Descriptions: 1510 1.2.2.3 Need for additional study 

Comment: - 73 FR 43503 - EPA requests comment on prohibiting injection into unmineable 

coal seam formations if they are above the lowermost USDW. 

Response: AMWA opposes the injection of CO2 into coal seams in general and as 

stated earlier recommends that EPA and DOE conduct additional research to 

determine the impacts of CO2 storage on coal seams. Furthermore, AMWA opposes 

Response: As described above, 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

51
performed in a manner that protects USDWs from endangerment. 

EPA recognizes that GS in unmineable coal seams has been the subject of less research than saline

formations or depleted oil and gas reservoirs. EPA continues to follow existing DOE projects and

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.

Commenter Name: Scott Anderson Letter ID: 0510

Commenter Organization: Environmental Defense Fund Comment ID: 21225

Comment: I would like to close with a few more suggested improvements. Again, we offer 

these with the idea that for the most part they are technical adjustments. 

First, although we're not necessarily in favor of doing it by excluding all 

formations beneath the lowest USDW, we are pleased that the agency has expressed 

some concern about coal, basalts, salt domes, and shales as formations that are 

suitable at this time for commercial sequestration. 

We think that the agency should directly exclude those kind of formations from 

this rule, this rule was written and risks were analyzed with the brine 

formations and petroleum reservoirs in mind. And these other sorts of 

formations we believe are worthy of research, it should be kept under the 

classified status for now. 

Response: The final GS rule does not preclude injection into any non-USDW formation type

provided owners or operators can demonstrate that GS can be performed in a manner that protects

USDWs from endangerment as required under today’s rulemaking. EPA acknowledges that there

may be risks associated with GS into coal, basalts, salt domes, and shales, which have been the

subject of limited experimental projects in the past. EPA will continue to review data on early GS

projects, including those in such formations, to determine whether the appropriate amount and types

of information and documentation are required and being collected. 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 appropriate or necessary.

Commenter Name: Scott Anderson Letter ID: 0520

Commenter Organization: Environmental Defense Fund Comment ID: 21427

Other EPA Comment Codes and Descriptions: 1510 1.2.2.3 Need for additional study; 2200 1.6.4

Other formation types 

Comment: Other suggestion and improvements for the rule are that coal seams, the basalts, 

hollowed out salt domes and shale are simply not ready for commercial 

sequestration at this time. And that is true whether or not they are below the 

lowest USDW. So our recommendation is that the Class VI proposal clearly be 

written not to apply to these sorts of formations. We do favor continued 

experimentation in these formations and some of them, especially coal seams may 

become commercially viable in the future, but for now we think they should be 

written, should be permitted under Class V. We should await further knowledge 

before deciding precisely that those formations not to be regulated. 

52
Response: EPA acknowledges that there may be risks associated with GS, particularly regarding GS

into coal seams, basalts, salt domes, shales, which have been the subject of limited experimental

projects in the past. EPA anticipates that in the short-term, GS into these types of formations will

continue to be experimental in nature (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 will continue to review data on early GS projects, including those in such

formations, to determine whether the appropriate amount and types of information and

documentation are required and being collected. 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 appropriate or necessary.

Commenter Name: George Peridas Letter ID: 0534

Commenter Organization: Natural Resources Defense Council (NRDC) Comment ID: 21459

Other EPA Comment Codes and Descriptions: 2200 1.6.4 Other formation types 

Comment: I do believe that discretion in some media is, if you like, good to go. And 

likewise, I do not believe that sequestration of the media is ready and in that 

range, in that category, I would include basalts, coal seems, organic shales and 

limestone. I think this should still continue any injections and those should 

continue to be regulated under Class V and I do not think we are ready to move 

to a wide scale endorsement of CO2 injection as a sequestration technique in 

those. 

Response: EPA acknowledges that site-suitability 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

any non-USDW formation type provided owners or operators can demonstrate that GS can be

performed in a manner that protects USDWs from endangerment. The Agency acknowledges that GS

into basalts, coal seams, shales, and limestone formations will likely have limited application, or that

owners or operators seeking Class VI permits for injection into these formations may not be able to

meet the final GS requirements or demonstrate protection of USDWs. 

The purpose of the GS rule is to ensure protection of USDWs, and the rule includes requirements to

ensure that the geologic formations are adequate to receive and confine injected CO2, at §146.83.

The siting, well construction, operational, and other requirements in the GS rule are designed to

ensure that injected CO2 remains within the target formation. 

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into

basalts, which have been the subject of limited experimental projects in the past. EPA anticipates

that in the short-term, GS into basalts, coal seams, salt domes, organic shales, limestone formations

will continue to be experimental in nature (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 will continue to review data on early GS projects, including those in

such formations, to determine whether the appropriate amount and types of information and

documentation are required and being collected. 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 appropriate or necessary.

53
Comment Code: 2200 1.6.4 Other formation types 

Individual Comments

Commenter Name: James Stine Letter ID: 0163

Commenter Organization: National Rural Electric Cooperative Association

(NRECA)

Comment ID:

21324

Other EPA Comment Codes and Descriptions: 2163 1.6.3.1 Comments in favor of injection into

unmineable coal seams 

Comment: 3. NRECA believes that the Final Rule should not contain a blanket prohibition 

on injection of CO2 into coal seams (whether above or below the lowermost USDW) 

or into other formations such as basalts, salt domes, or shales. 73 Fed. Reg. at 

43503. If it can be demonstrated that the injection of CO2 into such sites is 

protective of USDWs, then such activities should remain available options under 

the Class VI UIC program. 

Response: The final GS rule does not preclude injection into any non-USDW formations, including

coal seams, provided the site-suitability requirements in the GS rule are met, and owners or

operators can demonstrate that GS can be performed in a manner that protects USDWs from

endangerment. 

EPA acknowledges that there are unknowns regarding GS into formations such as coal seams, which

have been the subject of limited experimental projects in the past. For this reason, the Agency is

using an adaptive approach to regulate GS injection. EPA will collect and review project data on

early GS projects, including those that inject into various formation types, to determine whether the

appropriate amount and types of information and documentation are being collected. 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 appropriate or necessary.

EPA clarifies that the final rule requires that injection 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.

Commenter Name: Theresa Pugh Letter ID: 0169

Commenter Organization: American Public Power Association Comment ID: 23414

Comment: for comments on basalt, salt domes or shales. APPA is not qualified to offer any 

opinions about formations such as basalts, salt domes, or shales. APPA presumes 

that these site choice issues will be clearer after demonstrations by the U.S. 

DOE regional partnership and private R&D pilots. Id. at 43503. If it can be 

demonstrated that the injection of CO2 into such sites is protective of USDWs, 

then such activities should be allowed under the Class VI UIC program. At a 

minimum, we know that more demonstration projects are needed looking at diverse 

geology for maximum use of coal which is an essential fuel source. 

Response: The final GS rule does not preclude injection into any non-USDW formation type

54
provided owners or operators can demonstrate that GS can be performed in a manner that protects

USDWs from endangerment. The Agency acknowledges that GS into basalts, salt domes, and shales

will likely have limited application, or that owners or operators seeking Class VI permits for

injection into these formations may not be able to meet the final GS requirements or demonstrate

protection of USDWs. 

The purpose of the GS rule is to ensure protection of USDWs, and the rule includes requirements to

ensure that the geologic formations are adequate to receive and confine injected CO2, at §146.83.

The siting, well construction, operational, and other requirements in the GS rule are designed to

ensure that injected CO2 remains within the target formation. 

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into

basalts, which have been the subject of limited experimental projects in the past. EPA anticipates

that in the short-term, GS into basalts, salt domes, shales, limestone formations, and fractured karst

will continue to be experimental in nature (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 will continue to review data on early GS projects, including those in

such formations, to determine whether the appropriate amount and types of information and

documentation are required and being collected. 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 appropriate or necessary.

Commenter Name: James Rower Letter ID: 0173

Commenter Organization: Utility Solid Waste Activities Group (USWAG) Comment ID: 23481

Other EPA Comment Codes and Descriptions: 4410 2.4.4.3.1 Comments in favor of allowing

injection above/between USDWs in certain circumstances; 4430 2.4.4.3.3 Injection into coal seams

above USDWs (seeking comment) 

Comment: of USDWs and meet other applicable conditions for Class VI CO2GS wells. As a 

result, USWAG believes that the Final Rule should not contain a blanket 

prohibition on injection of CO2 into coal seams (whether above or below the 

lowermost USDW) or into other formations such as basalts, salt domes, or shales. 

73 Fed. Reg. at 43503. If it can be demonstrated that the injection of CO2 into 

such sites is protective of USDWs, then such activities should remain available 

options under the Class VI UIC program. 

Response: The final GS rule does not preclude injection into any non-USDW formation type

provided owners or operators can demonstrate that GS can be performed in a manner that protects

USDWs from endangerment as required under today’s rulemaking. The Agency acknowledges that

GS into basalts, coal seams, salt domes, and shales will likely have limited application, or that

owners or operators seeking Class VI permits for injection into these formations may not be able to

meet the final GS requirements or demonstrate protection of USDWs. 

The purpose of the GS rule is to ensure protection of USDWs, and the rule includes requirements to

ensure that the geologic formations are adequate to receive and confine injected CO2, at §146.83.

The siting, well construction, operational, and other requirements in the GS rule are designed to

ensure that injected CO2 remains within the target formation. 

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into

55
basalts, which have been the subject of limited experimental projects in the past. EPA anticipates

that in the short-term, GS into basalts, coal seams, salt domes, and shales will continue to be

experimental in nature (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 will continue to review data on early GS projects, including those in such formations, to

determine whether the appropriate amount and types of information and documentation are required

and being collected. 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 appropriate or

necessary.

EPA clarifies that the final rule requires that injection 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.

Commenter Name: Paul Pike Letter ID: 0198

Commenter Organization: Ameren Corporation Comment ID: 23943

Other EPA Comment Codes and Descriptions: 2163 1.6.3.1 Comments in favor of injection into

unmineable coal seams 

Comment: SITING 

Ameren understands that EPA must consider the potential impact of CO2 GS 

projects on USDWs and other pre-existing subsurface activities (e.g., natural 

gas storage operations). However, we believe that at this point, the imposition 

of prohibition on certain sites will limit the benefits of this program. The 

important criteria is protecting USDWs and meeting other applicable conditions 

for Class VI CO2 GS wells. As stated earlier, CO2 GS is still being developed 

for commercial scale use and methods may be developed to address all issues that 

would otherwise result in impacts on other subsurface activities. This means 

that there should not be a prohibition on injection of CO2 into coal seams 

(whether above or below the lowermost USDW) or into other formations such as 

basalts, salt domes, or shales. 73 Fed. Reg. at 43503. 

Response: EPA agrees that GS into unmineable coal seams has the potential to allow sequestration

while ensuring USDW protection from endangerment, as described by commenters citing the process

of enhanced methane recovery. The final GS rule does not preclude injection into unmineable coal

seams, or into basalts, salt domes, or shales, provided owners or operators can demonstrate that GS

can be performed in a manner that protects USDWs from endangerment. The Agency clarifies that

owners or operators of Class VI wells used for injecting CO2 into these formation types are subject

to the same site characterization, well construction, operation, monitoring, post-injection site care

and site closure requirements that are required of projects injecting into other formation types. 

EPA acknowledges that there are unknowns associated with GS, particularly regarding GS into

formations such as coal seams, basalts, salt domes, or shales, which have been the subject of limited

experimental projects in the past. For this reason, the Agency is using an adaptive approach to

regulate GS injection. EPA will collect and review project data on early GS projects, including those

that inject into various formation types, to determine whether the appropriate amount and types of

information and documentation are being collected. EPA plans, every six years, to collect and review

56
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 clarifies that the final rule requires that injection 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.

Commenter Name: Chris M. Hobson Letter ID: 0201

Commenter Organization: Southern Company Comment ID: 22163

Other EPA Comment Codes and Descriptions: 2163 1.6.3.1 Comments in favor of injection into

unmineable coal seams 

Comment: The same logic argues against blanket prohibitions on injection in coal seams or 

other formations such as basalts, salt domes, or shales: if a scientific and 

technical demonstration can be made showing that the injection of CO2 into one 

of these formations will be protective of USDWs, then that formation should 

remain an available option under the Class VI UIC Program. See id. at 43503. 

Response: The final GS rule does not preclude injection into any non-USDW formations, such as

basalts, salt domes, or shales, provided the site-suitability requirements in the GS rule are met, and

owners or operators can demonstrate that GS can be performed in a manner that protects USDWs

from endangerment. 

EPA acknowledges that there are unknowns associated with GS, particularly regarding GS into

formations such as coal seams, basalts, salt domes, or shales, which have been the subject of limited

experimental projects in the past. For this reason, the Agency is using an adaptive approach to

regulate GS injection. EPA will collect and review project data on early GS projects, including those

that inject into various formation types, to determine whether the appropriate amount and types of

information and documentation are being collected. 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 appropriate or necessary.

EPA clarifies that the final rule requires that injection 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.

Commenter Name: Kurt Waltzer Letter ID: 0250

Commenter Organization: Clean Air Task Force Comment ID: 22296

Other EPA Comment Codes and Descriptions: 2160 1.6.3 Unmineable coal seams 

Comment: The rule should explicitly exclude from Class VI efforts to sequester CO2 in 

basalts, coal seams, salt caverns and shales, which instead should be regulated 

under Class V Experimental 

We believe that EPA has ample basis for adopting rules to regulate geologic 

sequestration in hydrocarbon reservoirs and in deep brine formations. For these 

57
types of geologic formations, there is a widespread technical consensus on how 

to assess and manage risks, what data is needed to characterize sites, how to 

select sites, how to conduct injection operations, how to model the behavior of 

CO2 in the reservoir, and how to monitor project performance. There is no such 

consensus, however, regarding sequestration in basalts, coal seams, salt caverns 

and shales. The trapping mechanisms of CO2 and/or the operational engineering 

involved in such operations is significantly different to those in deep saline 

formations and hydrocarbon reservoirs, and using identical regulatory language 

would be ill advised. In fact, it is not known at this time whether 

sequestration (or even injection in some cases) can even be done at scale in 

such formations - efforts in these formations are very much still in the 

experimental stage. There is no basis at this time for determining whether rules 

that are appropriate for wells in hydrocarbon reservoirs and deep saline 

formations are also appropriate for wells in these other formations. Until there 

is better understanding of whether and how sequestration can be safely 

accomplished in basalts, coal seams, salt caverns and shales, wells in these 

formations should be treated as experimental wells under Class V. 

Projects designed to evaluate injection in coal seams, salt caverns and shales 

should be permitted under the UIC Class V provisions and subject to the March 

2007 Guidance on "Using the Class V Experimental Technology Well Classification 

for Pilot GS Projects. [FN20] This Guidance clearly states that Class V is 

intended only for projects "...designed to evaluate the technical issues 

associated with CO2 injection" [FN21]. The Director should review all Class V GS 

permit applications to insure that they meet the definition of Pilot Project in 

CFR 146.3: "... a technology which has not proven feasible under the conditions 

in which it is being tested." The purpose of such pilot projects should be to 

gather and share information which will lead to a clearer understanding of the 

feasibility of such projects on a commercial scale. 

[FN20: UICPG#83] 

[FN21: Id. at p. 1] 

In order to implement our suggestion regarding these formations, we recommend 

revising sections 144.6(f), 144.80(f), 146.5(f) and the definition of 

sequestration in §146.81 accordingly. We suggest retaining the provision in 

proposed §144.15 that the construction, operation or maintenance of any nonexperimental Class V geologic sequestration well is prohibited. 

Response: EPA acknowledges that site-suitability 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

any formation type provided owners or operators can demonstrate that GS can be performed in a

manner that protects USDWs from endangerment. The Agency acknowledges that GS into basalts,

coal seams, salt domes, shales, limestone formations, and fractured karst will likely have limited

application, or that owners or operators seeking Class VI permits for injection into these formations

may not be able to meet the final GS requirements or demonstrate protection of USDWs. 

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into

basalts, which have been the subject of limited experimental projects in the past. EPA anticipates

that in the short-term, GS into basalts, coal seams, salt domes, shales, limestone formations, and

58
fractured karst will continue to be experimental in nature (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 will continue to review data on early GS projects, including

those in such formations, to determine whether the appropriate amount and types of information and

documentation are required and being collected. 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 appropriate or necessary.

Commenter Name: Walter L. Baker Letter ID: 0253

Commenter Organization: Utah Division of Water Quality Comment ID: 22344

Other EPA Comment Codes and Descriptions: 2160 1.6.3 Unmineable coal seams 

Comment: PROHIBITIONS - COAL SEAMS, BASALTS, SALT DOMES, SHALES, OTHER

FORMATIONS, 

We do not support the categorical prohibition of CO2 geologic sequestration in 

coal seams, basalts, salt domes, shales or any other formation. EPA states in 

the preamble to the proposed rule that "[t]hese formations are limited in 

geographic and geologic distribution throughout the U.S., and their 

technological or economic viability as GS [geologic sequestration] sites have 

not been demonstrated." For this very reason, these formations should not be 

eliminated as possible sequestration reservoirs. Ongoing demonstration projects 

conducted under the Department of Energy may yet demonstrate their viability. 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

as a Class VI well. 

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into

formations such as coal seams, basalts, salt domes, or shales, which have been the subject of limited

experimental projects in the past. For this reason, the Agency is using an adaptive approach to

regulate GS injection. EPA will collect and review project data on early GS projects, including those

that inject into various formation types, to determine whether the appropriate amount and types of

information and documentation are being collected. 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 appropriate or necessary.

Commenter Name: William Herz Letter ID: 0266

Commenter Organization: The Fertilizer Institute Comment ID: 22878

Comment: Target Geologic Formations for GS of CO2 

59
TFI agrees that other abandoned mines, including potash mines, are potential 

CO2 storage options and would be willing to assist EPA in exploring this option 

further. (73 Fed. Reg. 43,503) 

Response: 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 are designed to ensure that injected CO2

remains within the target formation. If an owner 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 protects USDWs and meets all of the requirements of the GS rule, the project may be permitted

as a Class VI well. 

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into

formations such as coal seams, basalts, salt domes, or shales, which have been the subject of limited

experimental projects in the past. For this reason, the Agency is using an adaptive approach to

regulate GS injection. EPA will collect and review project data on early GS projects, including those

that inject into various formation types, to determine whether the appropriate amount and types of

information and documentation are being collected. 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 appropriate or necessary.

Commenter Name: John McManus Letter ID: 0294

Commenter Organization: American Electric Power Comment ID: 25307

Other EPA Comment Codes and Descriptions: 2048 1.5.2.4 Oppose Class VI/ Support Class V

experimental technology well 

Comment: There is less technical support on the ability to conduct GS in basalts, coal 

seams, salt caverns, and shales. As compared with deep saline formations and 

hydrocarbon reservoirs, the trapping/containment mechanisms of CO2 and/or 

operational engineering involved in basalts, coal seams, salt caverns and shales 

may be significantly different and using identical regulatory language might not 

be appropriate. In fact, it is not known at this time whether GS (or even 

injection in some cases) can be done at commercial scale in each of these types 

of formations - GS efforts in these formations are still in the experimental 

stage. Wells in basalts, coal seams, salt caverns and shale formations should 

be treated as experimental wells under Class V, recognizing that completing the 

process of research, development and demonstration likely will require initial 

full scale experimental projects in addition to pilot projects. 

Keeping these wells under Class V would allow EPA and the states to gain enough 

experience to develop suitable permitting requirements for such wells and to 

tailor those requirements at both the pilot and commercial scales until the 

agencies are ready to regulate such wells under an appropriate class. 

Response: EPA clarifies that the final GS rule does not categorically preclude injection of CO2 into

60
any formation types. Experimental research projects will continue to be regulated as Class V

experimental technology wells as long as they remain of an experimental nature. EPA clarifies that

existing experimental GS projects may be permitted as described in UIC Program Guidance #83:

Using the Class V Experimental Technology Well Classification for Pilot Carbon Geologic

Sequestration Projects, which provided information for permitting authorities to consider when

permitting experimental GS projects (i.e., those 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 are 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 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. 

EPA clarifies those Class V experimental projects subject to Guidance #83 will be those wells that

test new technologies for purposes of GS. The Agency also clarifies that it does not consider it

appropriate to permit CO2 injection wells that are testing the injectivity or appropriateness of an

individual formation (e.g., as a prelude to a commercial-scale operation) as Class V experimental

technology wells. Such wells must be permitted as Class VI wells.

EPA is preparing an addendum to UICPG #83 that describes the use of the Class V experimental

technology well classification 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. This

guidance will be available on EPA’s website at

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm.

Commenter Name: John McManus Letter ID: 0294

Commenter Organization: American Electric Power Comment ID: 25308

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

language; 2048 1.5.2.4 Oppose Class VI/ Support Class V experimental technology well 

Comment: To implement this approach, sections 144.6(f), 144.80(f), 146.5(f) and the 

definition of sequestration in 146.81 should be revised. The proposed 144.15 

provision that the construction, operation or maintenance of any nonexperimental Class V GS well is prohibited should be retained, but only with the 

understanding that this prohibition is not intended to limit the size or scale 

of any experimental GS operation. 

"Class VI. Wells used for geologic sequestration 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 until such time as the 

Administrator establishes separate requirements by rule for the specific type of 

formation or determines, following public notice and opportunity for comment, 

that wells used for geologic sequestration 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 final regulation; the construction, operation or

maintenance of any non-experimental Class V GS well is prohibited under the final rule. The final

rule contains tailored requirements for Class VI wells to ensure that GS projects are permitted, sited,

61
constructed, operated, and closed in a manner 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 experimental research projects will continue to be

regulated as Class V experimental technology wells as long as they remain of an experimental

nature.

Commenter Name: Scott Anderson Letter ID: 0520

Commenter Organization: Environmental Defense Fund Comment ID: 21427

Other EPA Comment Codes and Descriptions: 1510 1.2.2.3 Need for additional study; 2166

1.6.3.2 Comments opposing injection into unmineable coal seams 

Comment: Other suggestion and improvements for the rule are that coal seams, the basalts, 

hollowed out salt domes and shale are simply not ready for commercial 

sequestration at this time. And that is true whether or not they are below the 

lowest USDW. So our recommendation is that the Class VI proposal clearly be 

written not to apply to these sorts of formations. We do favor continued 

experimentation in these formations and some of them, especially coal seams may 

become commercially viable in the future, but for now we think they should be 

written, should be permitted under Class V. We should await further knowledge 

before deciding precisely that those formations not to be regulated. 

Response: EPA acknowledges that there may be risks associated with GS, particularly regarding GS

into coal seams, basalts, salt domes, shales, which have been the subject of limited experimental

projects in the past. EPA anticipates that in the short-term, GS into these types of formations will

continue to be experimental in nature (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 will continue to review data on early GS projects, including those in such

formations, to determine whether the appropriate amount and types of information and

documentation are required and being collected. 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 appropriate or necessary.

Commenter Name: George Peridas Letter ID: 0534

Commenter Organization: Natural Resources Defense Council (NRDC) Comment ID: 21459

Other EPA Comment Codes and Descriptions: 2166 1.6.3.2 Comments opposing injection into

unmineable coal seams 

Comment: I do believe that discretion in some media is, if you like, good to go. And 

likewise, I do not believe that sequestration of the media is ready and in that 

range, in that category, I would include basalts, coal seems, organic shales and 

limestone. I think this should still continue any injections and those should 

continue to be regulated under Class V and I do not think we are ready to move 

to a wide scale endorsement of CO2 injection as a sequestration technique in 

those. 

Response: EPA acknowledges that site-suitability 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

any non-USDW formation type provided owners or operators can demonstrate that GS can be

62
performed in a manner that protects USDWs from endangerment. The Agency acknowledges that GS

into basalts, coal seams, shales, and limestone formations will likely have limited application, or that

owners or operators seeking Class VI permits for injection into these formations may not be able to

meet the final GS requirements or demonstrate protection of USDWs. 

The purpose of the GS rule is to ensure protection of USDWs, and the rule includes requirements to

ensure that the geologic formations are adequate to receive and confine injected CO2, at §146.83.

The siting, well construction, operational, and other requirements in the GS rule are designed to

ensure that injected CO2 remains within the target formation. 

EPA acknowledges that there may be risks associated with GS, particularly regarding GS into

basalts, which have been the subject of limited experimental projects in the past. EPA anticipates

that in the short-term, GS into basalts, coal seams, salt domes, organic shales, limestone formations

will continue to be experimental in nature (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 will continue to review data on early GS projects, including those in

such formations, to determine whether the appropriate amount and types of information and

documentation are required and being collected. 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 appropriate or necessary.

Comment Code: 2300 1.7 Comments on the Alternatives Considered 

Individual Comments

Commenter Name: Carl Carlsson Letter ID: 0131

Commenter Organization: SUEZ Energy Generation NA, LLC Comment ID: 21528

Comment: Proposed Regulatory Alternatives 

SEGNA agrees that options 1 and 4 ("Non-Specific Requirements Approach" 

and "Highly Specific Requirements Approach", respectively) are not appropriate for 

the reasons stated by EPA. Alternative 3, "Tailored Requirements Approach" 

suggested by EPA might be the best alternative since it builds on the existing UIC 

regulatory framework, though flexibility regarding specific program elements 

should be considered on a case-by-case basis, as appropriate, pursuant to 

the "General Requirements Approach" under Alternative 2. 

Response: EPA agrees with the commenters that Regulatory Alternative 3 is appropriate. 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

full-scale CO2 GS, including the volumes of CO2 to be injected, the buoyant and mobile nature of

the injectate, and its corrosivity in the presence of water. 

Even though the Agency did not choose Alternatives 1 or 2, EPA agrees that flexibility is important

to accommodate the varied conditions that may be encountered at GS sites while ensuring the

protection of USDWs. The regulation provides flexibility for selection of appropriate sites and target

formations (under §146.82), well construction specifics (under §146.86), and testing and monitoring

63
regimes (under §146.90), provided the owner or operator can demonstrate that the injection and

storage will not endanger USDWs and that minimum requirements for the site are met.

Commenter Name: Bradley J. Field Letter ID: 0186

Commenter Organization: New York State Dept. of Environmental Conservation

Div. of Mineral Resources

Comment ID:

25178

Comment: H. EPA is proposing Regulatory Alternative 3, the Tailored Requirements 

Approach. EPA did not select Alternative 1 (Non-Specific Requirements Approach) 

because it does not provide enough specificity to ensure that permitting 

authorities manage GS wells appropriately to prevent endangerment of USDWs. In 

addition, this alternative may be burdensome for owners or operators because of 

the potential for inconsistency across states and burdensome for permitting 

authorities who will likely be faced with developing their own technical 

approaches to regulating GS. 

NYSDEC-DMN Response: NYSDEC-DMN agrees that Regulatory Alternative 3, Tailored 

Requirements Approach is appropriate provided it allows discretion and 

flexibility on the part of the Director. 

Response: EPA agrees with the commenters that Regulatory Alternative 3 is appropriate. 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

full-scale CO2 GS, including the volumes of CO2 to be injected, the buoyant and mobile nature of

the injectate, and its corrosivity in the presence of water. 

Even though the Agency did not choose Alternatives 1 or 2, EPA agrees that flexibility is important

to accommodate the varied conditions that may be encountered at GS sites while ensuring the

protection of USDWs. The final GS regulation gives the Director discretion to set permit criteria that

are appropriate to site-specific conditions. The regulation provides flexibility to select 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 demonstrate that the

injection and storage will not endanger USDWs and that minimum requirements for the site are met.

Commenters representing electric utilities, water associations, and states supported Alternative 3 and

the flexibility it provides to permitting authorities to make case-by-case permitting decisions while

ensuring the protection of USDWs.

Commenter Name: Diane VanDe Hei Letter ID: 0213

Commenter Organization: Association of Metropolitan Water Agencies

(AMWA)

Comment ID:

22929

Comment: Regulatory alternative: EPA’s proposed Alternative 3 for permitting CO2 

geosequestration appears to be the best approach in that it would allow for 

projects to move forward. AMWA supports this approach because it provides the 

permitting authority with discretion to require additional information from 

owner/operators applying for a permit and to make case-by-case permitting 

decisions. This is important as water chemistry and subsurface geology differ 

widely across the country. 

Response: EPA agrees with the commenters that Regulatory Alternative 3 is appropriate. The

technical requirements in Alternative 3 (and the final GS rule) build upon the long-standing UIC

64
regulatory framework for deep wells and are appropriately tailored to address the unique nature of

full-scale CO2 GS, including the volumes of CO2 to be injected, the buoyant and mobile nature of

the injectate, and its corrosivity in the presence of water. 

Even though the Agency did not choose Alternatives 1 or 2, EPA agrees that flexibility is important

to accommodate the varied conditions that may be encountered at GS sites while ensuring the

protection of USDWs. The final GS regulation gives the Director discretion to set permit criteria that

are appropriate to site-specific conditions and to require submission of additional information when

necessary. The regulation provides flexibility 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 demonstrate that the injection and storage will

not endanger USDWs and that minimum requirements for the site are met.

Commenter Name: Robert E. Carter Jr. Letter ID: 0236

Commenter Organization: Indiana Department of Natural Resources (IDNR) Comment ID: 23205

Other EPA Comment Codes and Descriptions: 1250 1.1.1.4 Flexibility is needed (performancebased standards) 

Comment: Section III -Proposed Regulatory Alternatives 

Subsection A -Proposed Alternative 

Comment: Of the four alternatives considered by EPA, we appreciate the fact that 

the highly specific requirements approach of Alternative 4 was not chosen. 

However, even with the selected Alternative 3, we believe that EPA still must 

provide some of the flexibility that was to be considered under Alternative 2. 

We are somewhat troubled by EPA's statement that it "did not select this 

alternative (Alternative 2) because it is not tailored to meet the unique 

challenges of long-term C02 storage. While this option includes flexibility for 

permit authorities to add requirements, EPA cannot be certain that the necessary 

adjustments would be made." 

Response: Even though the Agency did not choose Alternative 2, EPA agrees that flexibility is

important to accommodate the varied conditions that may be encountered at GS sites while ensuring

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

full-scale CO2 GS, including the volumes of CO2 to be injected, the buoyant and mobile nature of

the injectate, and its corrosivity in the presence of water. 

The regulation provides flexibility 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 demonstrate that the injection and storage will not

endanger USDWs and that minimum requirements for the site are met.

Letter ID: 0263

Commenter Organization: Interstate Oil & Gas Compact Commission Comment ID: 22794

Comment: III . Proposed Regulatory Alternatives 

J. EPA is proposing Regulatory Alternative 3, the Tailored Requirements Approach. 

EPA did not select alternative 1 (Non-Specific Requirements Approach) because it 

65
does not provide enough specificity to ensure that permitting authorities manage 

GS wells appropriately to prevent endangerment of USDWs. In addition, this 

alternative maybe burdensome for owners or operators because of the potential for 

inconsistency across States and burdensome for permitting authorities who will 

likely be faced with developing their own technical approaches to regulating GS. 

IOGCC Response: The IOGCC strongly believes that Alternative II is the better 

approach with some additional strengthening. This would allow necessary 

discretion and flexibility on the part of the Director. The alternative proposed 

by EPA, Alternative III, although described as "giving permitting authorities 

discretion in how to permit certain elements" appears to offer very limited 

discretion and flexibility to the Director. Alternative III is unnecessarily 

prescriptive. 

Response: Although Alternative 2 (General Requirements Approach) provides standards for siting,

construction, operation, and monitoring associated with basic deep well design and operation, EPA

does not believe that this alternative is appropriate for GS because it does not contain requirements

tailored to meet the unique challenges of long-term CO2 GS, including the potentially large injection

volumes, buoyancy, corrosivity in the presence of water, and viscosity and therefore cannot ensure

protection USDWs. 

EPA believes that the GS rule offers states the flexibility and discretion desired by commenters

preferring Alternative 2 while ensuring the protection of USDWs. The final GS regulation gives the

Director discretion to set permit criteria that are appropriate to site-specific conditions. The

regulation provides flexibility to select 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 demonstrate that the injection and storage will not endanger

USDWs and that minimum requirements for the site are met. Commenters representing electric

utilities, water associations, and states supported Alternative 3 and the flexibility it provides to

permitting authorities to make case-by-case permitting decisions while ensuring the protection of

USDWs.

Commenter Name: Steven Chester Letter ID: 0264

Commenter Organization: Michigan Department of Environmental Quality

(MDEQ)

Comment ID:

22834

Comment: EPA (III .) proposes adopting Regulatory Alternative 3, the Tailored 

Requirements Approach, for managing CO2 injection for GS. 

- Staff believes that Regulatory Alternative 2, the General Requirements 

Approach, is the proper management approach because it gives the permitting 

authorities the necessary flexibility and discretion to properly manage CO2 GS. 

Response: Although Alternative 2 (General Requirements Approach) provides standards for siting,

construction, operation, and monitoring associated with basic deep well design and operation, EPA

does not believe that this alternative is appropriate for GS because it does not contain requirements

tailored to meet the unique challenges of long-term CO2 GS, including the potentially large injection

volumes, buoyancy, corrosivity in the presence of water, and viscosity and therefore cannot ensure

protection of USDWs.

EPA believes that the GS rule offers states the flexibility and discretion desired by commenters

66
preferring Alternative 2 while ensuring the protection of USDWs. The final GS regulation gives the

Director discretion to set permit criteria that are appropriate to site-specific conditions. The

regulation provides flexibility to select 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 demonstrate that the injection and storage will not endanger

USDWs and that minimum requirements for the site are met. Commenters representing electric

utilities, water associations, and states supported Alternative 3 and the flexibility it provides to

permitting authorities to make case-by-case permitting decisions while ensuring the protection of

USDWs.

Commenter Name: Donn Miller Letter ID: 0270

Commenter Organization: State of Oregon, Water Resources Department Comment ID: 22885

Comment: III Proposed Regulatory Alternatives 

We recommend alternative #3. 

These rules are more of a performance standard than construction standards. In 

order to fully protect groundwater aquifers and the environment, the rules should 

more fully regulate the construction of class VI wells by the use of detailed 

construction standards along with performance standards. 

Response: EPA agrees with the commenters that Regulatory Alternative 3 is appropriate. 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

full-scale CO2 GS, including the volumes of CO2 to be injected, the buoyant and mobile nature of

the injectate, and its corrosivity in the presence of water. 

The tailored approach in this alternative (and the final GS rule) modifies the existing UIC

requirements for site characterization, area of review, well construction, mechanical integrity testing,

monitoring, well plugging, post-injection site care, and site closure, to address full-scale GS. This

approach promotes USDW protection, incorporates flexibility or the discretion of the permitting

authority when appropriate, seeks to limit burden on owners or operators and permitting agencies,

and provides a foundation for national consistency in permitting of GS projects. 

EPA adds that the construction requirements at §146.86 provide an appropriate level of protection

from endangerment to USDWs that is based upon the existing UIC framework for deep wells. The

new tailored construction requirements in the final GS rule offer a balance between specific

standards and flexibility to address site-specific conditions and are tailored to address the unique

nature of CO2 GS (i.e., very large volumes, very long time-periods, and pressurized reservoirs).

Comment Code: 2320 1.7.2 Comments on Alternative 1 

Individual Comments

Commenter Name: James Dooley Letter ID: 0156

Commenter Organization: Joint Global Change Research Institute, Pacific Comment ID:

67
Northwest National Laboratory 22622

Other EPA Comment Codes and Descriptions: 1540 1.2.3.2 Climate change legislation 

Comment: Page 43504. In laying out its reasoning for why it did not select Regulatory 

Alternative Number 1 as the basis of the proposed Class VI rule, the USEPA 

correctly notes that there is value in having a common federal approach as there 

are many potential CCS adopters that will operate facilities in numerous 

different states. This is true and it is appropriate for USEPA to note this. It 

is also important to realize that there are numerous reasons for pursuing a 

common federal approach and that decision will cascade through numerous parts of 

the proposed rule and how it is implemented in practice and how it is integrated 

into a future national climate policy. 

Response: As described above, EPA agrees that a consistent approach to regulating GS activities

across the United States is important. 

EPA believes that the technical requirements in Regulatory Alternative 3 build upon the existing UIC

regulatory framework for deep wells and are appropriately tailored to address the unique nature of

full-scale CO2 GS, including the volumes of CO2 being anticipated for long-term storage, the

buoyant and mobile nature of the injectate, and its corrosivity in the presence of water. 

This approach provides a foundation for national consistency in permitting of GS projects, promotes

USDW protection, incorporates flexibility or the discretion of the permitting authority when

appropriate, and seeks to limit burden on owners or operators and permitting agencies. The tailored

approach in this alternative (and the final GS rule) modifies the existing UIC requirements for site

characterization, area of review, well construction, mechanical integrity testing, monitoring, well

plugging, post-injection site care, and site closure, to address full-scale GS. 

Comment Code: 2330 1.7.3 Comments on Alternative 2 

Individual Comments

Commenter Name: Dwight Lockwood, PE, QEP Letter ID: 0141

Commenter Organization: Global Energy, Inc. Comment ID: 23105

Comment: Alternative Selection 

1.EPA proposes four alternatives for GS regulations and asks for comments on 

them. Our fundamental belief is that the program should be as simple and 

pragmatic as possible, and in recognition of the initial rigor involved, once 

the well is sited, and installed, the risk of a leak is extremely minimal. 

2.As such, we support EPA’s selection of Alternative 2, as a balance between the 

rigor and the security, delegating much of implementation to the states, who 

have local knowledge. 

Response: EPA clarifies that it proposed Alternative 3 and subsequently has chosen Alternative 3 in

the final rule. The technical requirements in Alternative 3 provide a balance between rigor and

security and build upon the long-standing UIC regulatory framework for deep wells and are

68
appropriately tailored to address the unique nature of full-scale CO2 GS, including the volumes of

CO2 to be injected, the buoyant and mobile nature of the injectate, and its corrosivity in the presence

of water to ensure the protection of USDWs. Although Alternative 2 (General Requirements

Approach) provides standards for siting, construction, operation, and monitoring associated with

basic deep well design and operation, EPA does not believe that this alternative is appropriate for GS

because it does not contain requirements tailored to meet the unique challenges of long-term CO2

GS, including the potentially large injection volumes, buoyancy, corrosivity in the presence of water,

and low viscosity and therefore cannot ensure protection of USDWs.

EPA believes that the GS rule (Alternative 3) offers the flexibility and discretion desired by

commenters preferring Alternative 2 while protecting USDWs from endangerment. The final GS

regulation gives the Director discretion to set permit criteria that are appropriate to site-specific

conditions. The regulation provides flexibility to select 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 demonstrate that the injection and storage will not

endanger USDWs and that minimum requirements for the site are met. Commenters representing

electric utilities, water associations, and states supported Alternative 3 and the flexibility it provides

to permitting authorities to make case-by-case permitting decisions while ensuring the protection of

USDWs.

Comment Code: 2400 1.8 Comments on EPA's adaptive rulemaking process 

Individual Comments

Commenter Name: Karl R. Moor Letter ID: 0109

Commenter Organization: Southern Company, on behalf of Edison Electric

Institute (EEI)

Comment ID:

22009

Other EPA Comment Codes and Descriptions: 1250 1.1.1.4 Flexibility is needed (performancebased standards); 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 because they present a win-win situation: a 

higher level of environmental protection while fostering a regulatory regime 

that encourages investment in CCS projects. We also acknowledge 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 decisions 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 owners or operators flexibility.

Many of the permit requirements will be established through site-specific plans developed by the

owner or operator and approved by the Director, and 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 situations modify the length of the post-injection site care

period or approve an alternative post-injection site care timeframe as part of the permitting process

under §146.93, allow the use of alternate methods for mechanical integrity testing, and waive the

69
requirement that wells be designed to inject below the lowermost USDW. Additionally, 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 operator can demonstrate that the injection and storage will not endanger USDWs and that

minimum requirements 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 State, Tribal, and DI UIC

Program 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-specific and conditions will differ from

state to state. The GS rule balances the need for these site-specific decisions with the need for

minimum Federal requirements to ensure national consistency while ensuring the protection of

USDWs. To ensure the final rule is applied consistently, EPA is developing 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 primary enforcement responsibility (primacy) for GS Class VI

wells under Section 1422 of SDWA, as well as the technical and administrative issues related to

developing GS regulations that are the equivalent of minimum Federal criteria and requirements. The

guidance will be available at http://water.epa.gov/type/groundwater/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 sufficiently protected from endangerment, it will consider changes to the

permit requirements in the future.

Commenter Name: Paul Pike Letter ID: 0111

Commenter Organization: Ameren Corporation on behalf of USWAG Comment ID: 22407

Comment: 8. The Final Rule must not make the Class VI permit application process overly 

burdensome or unrealistic by requiring detailed information that may not be 

available at the time of the initial application; instead, the Final Rule should 

allow for submission of updated information regarding a Class VI well and its 

AoR as that information becomes available. 

Response: EPA believes that the permitting requirements for GS wells at §146.82 are appropriate.

The extensive data on the geologic site, AoR evaluation, and testing of the well during drilling that

owner or operators must submit are appropriate to ensure that permitting authorities have the

necessary information to evaluate whether a specific site will allow safe injection of CO2 and ensure

USDW protection from endangerment.

EPA recognizes that not all of the information listed at §146.82 of the proposed regulation would be

available at the time the owner or operator develops their initial permit application. Therefore, EPA

has revised this subpart 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). 

Commenter Name: Robert Bessette Letter ID: 0139

Commenter Organization: Council of Industrial Boiler Owners (CIBO) Comment ID: 23081

Comment: unquantified risk. EPA notes that it intends to finalize a rule in 2010 or 

2011.[FN1 1 Carbon Sequestration: Risks, Opportunities, and Protection of 

Drinking Water: Hearing Before the Subcomm. on Environment and Hazardous 

70
Materials of the H. Comm. on Energy and Commerce, 110th Cong. (2008) (statement 

of Benjamin H. Grumbles, Assistant Administrator for the U.S. Environmental 

Protection Agency).] Given the high degree of uncertainty on significant 

elements of this regulation, and the long period of time before EPA expects to 

finalize a rule, CIBO strongly urges EPA to seek additional notice and comment 

on subsequent developments in its data collection, analysis and decisions on 

this proposed approach. CIBO does believe, however, that rules covering 

Response: If EPA determines that changes to the regulations are appropriate based on its review of

GS project data, the Agency will provide an opportunity for the public to comment on the proposed

changes as well as any data on which the changes were based. EPA did provide more opportunity for

public notice and comment when it presented new data in its Notice of Data Availability and

Request for Comment. 

EPA disagrees that there is a high degree of uncertainty associated with GS. EPA considered

information from laboratory, modeling, and field research as it developed the requirements for GS

wells. In addition to laboratory studies and modeling research that provide relevant information on

GS, the Agency is also involved in collecting and analyzing GS project data and permit 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

(NETL), and several international projects. In addition to the information cited in the preamble to the

proposed rule, EPA published a Notice of Data Availability and Request for Comment (NODA) on

August 31, 2009 (74 FR 44802), in which the Agency described the preliminary results of research

at three DOE partnership sites (in Escatawpa, Mississippi; the Aneth Field in Paradox Basin,

Southeast Utah; and the Pump Canyon Site, New Mexico). EPA sought comment on this data and

used it to inform the final rule. 

Commenter Name: Richard Driggans Letter ID: 0145

Commenter Organization: Tennessee Valley Authority Comment ID: 23147

Other EPA Comment Codes and Descriptions: 1250 1.1.1.4 Flexibility is needed (performancebased standards) 

Comment: General Comment 

1. TVA acknowledges the challenge of developing a rule to provide regulatory 

certainty for the GS of CO2 in order to foster industry adoption of carbon capture 

and storage (CCS) in the face of considerable technological and experiential 

uncertainty about safely injecting and 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, this rule is justifiably 

stringent for protecting USDWs, ecological 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 appropriately where justified. TVA agrees with 

EPA that the regulatory standard for permitting CO2 GS wells should be the 

protection of USDWs, which must take precedence over the need to sequester CO2 

underground at any site. For this reason, TVA supports a stringent rule 

71
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 the UIC GS rulemaking is appropriate. The

Agency plans to use such an approach to ensure that USDWs are protected from endangerment while

making it possible to meet the potentially 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 pilot

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 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.

However, the Agency cannot definitively predict that future requirements will be less stringent than

those in the final GS rule. The Agency believes that the Class VI requirements appropriately address

the unique 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 implemented under the

adaptive rulemaking would be based on technical information and data generated and collected

during early GS projects or other research. 

EPA believes that reevaluating the GS requirements every six years is appropriate to allow sufficient

time for projects to be permitted, for State and Tribal programs to apply for and receive primacy,

and for sufficient project data to be collected. For example, once the first GS projects are permitted,

injection commences, and monitoring data are generated and analyzed, 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 plans 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 injecting), EPA will have additional opportunities to evaluate 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 apply 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.

Commenter Name: M. Michael Rounds Letter ID: 0159

Commenter Organization: Midwestern Governors Association (MGA) Comment ID: 22226

Comment: Adaptive approach We support the adaptive approach to regulatory development 

where relevant data based on demonstrations and commercial scale projects will 

be used to determine if the rule continues to appropriately meet the Safe 

Drinking Water Act (SDWA) objectives and if not, that they will be revised (73 

FR 43522). This language is included in the preamble, but it is not articulated 

in the language of the rule in terms of how the adaptive approach would be put 

into practice. As projects develop across different geologic formations and from 

72
various carbon sources, there will be increased knowledge and data on how to 

effectively manage these sites while meeting the objectives of the SDWA. It is 

not clear in the proposed rule by what method or mechanism the relevant 

knowledge and data would be collected by EPA and how the existing rule would be 

evaluated within the context of new information. 

Response: EPA agrees that an adaptive approach to the UIC GS rulemaking is appropriate. The

Agency plans on using such an approach to ensure that USDWs are protected from endangerment

and meet the potentially 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 pilot 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 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.

Commenter Name: James Rower Letter ID: 0173

Commenter Organization: Utility Solid Waste Activities Group (USWAG) Comment ID: 23473

Other EPA Comment Codes and Descriptions: 1250 1.1.1.4 Flexibility is needed (performancebased standards) 

Comment: 2. Necessity of a Flexible Regulatory Scheme 

USWAG applauds the efforts EPA has taken 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 operations are only at the nascent stage. 

The challenge confronting EPA in this rulemaking is to establish a costeffective and environmentally protective 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, it is critical that the Final Rule emphasize 

performance-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 directorial discretion and the suggestion that 

forthcoming guidance may be used to clarify other requirements. In general, we 

agree that 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. It is important, 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 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 provided on "economically significant" guidance 

73
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 absolutes in the Final Rule. We agree that the 

appropriate standard underlying the technical requirements for CO2 GS wells is 

the protection of USDWs. However, because it is difficult to know at this point 

what methods or technology will be developed 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 fully understood), provided that the Owner 

or Operator can show that the injection and storage will be protective of USDWs. 

[FN2] The Bulletin defines "economically significant guidance document" as "a 

significant guidance document that 'may reasonably 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 includes a balance of specific criteria to be met by the owner or

operator and areas of Directorial discretion. The Agency believes this 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

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 administrative issues

on developing GS regulations that are the equivalent of minimum federal criteria and requirements.

The guidance will provide recommended approaches for how permitting authorities may exercise

Director's discretion. The guidance will be available on EPA's web site, at

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm.

EPA also agrees that an adaptive approach to rulemaking for GS is appropriate. The Agency plans to

use such an approach to ensure that USDWs are protected from endangerment and meet the

potentially 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 pilot 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 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 disagrees that the GS rulemaking needs to be based solely on large-volume projects. While

studying the impact of injecting large volumes of CO2 is important, data on other aspects of GS—

including the buoyancy and corrosivity of CO2 in the presence of water, the potential presence of

impurities in captured CO2, and its mobility within subsurface formations—informed the

rulemaking.

74
Commenter Name: Quinlan J. Shea Letter ID: 0177

Commenter Organization: Edison Electric Institute Comment ID: 23568

Other EPA Comment Codes and Descriptions: 1852 1.4.2.1 DOE Regional Carbon Sequestration

Partnerships 

Comment: iv. Maintaining ability to incorporate new information. Any regulatory regime 

must be sufficiently flexible to adapt to new information. Indeed, regulation 

of ongoing GS "pilot" projects under the existing UIC regulations for Class I or 

V wells has been positive. EPA must take great care moving to a new or 

different regulatory framework while projects designed to gain more 

technological certainty, as well as the increased certainty about appropriate 

risk management solutions for CCS projects that would likely follow, are 

ongoing. Given that EPA has decided to move forward with GS-specific 

regulations, EEI urges the Agency to develop a framework that can consider and, 

as appropriate, incorporate data developed through CCS demonstration projects 

and the activities of the Department of Energy‘s Regional Carbon Sequestration 

Partnerships. 

Response: EPA agrees that an adaptive approach to the UIC GS rulemaking is appropriate. The

Agency plans to use such an approach to ensure that USDWs are protected from endangerment and

meet the potentially 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 pilot 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 collect and review data on GS projects, including the DOE Regional

Carbon Sequestration Partnership 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: Daniel Plath Letter ID: 0188

Commenter Organization: NiSource, Inc. Comment ID: 25226

Other EPA Comment Codes and Descriptions: 1250 1.1.1.4 Flexibility is needed (performancebased standards) 

Comment: Recognizing that a great deal of this technology is currently in development and 

will not be commercially deployed for several years, it is vital that the final 

rule, if necessary, include reasonable performance based regulations that can be 

swiftly adjusted and finetuned as experience 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 implementation 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 

phase 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, including lessons learned from the both the 

technical and regulatory perspective, could then be utilized to develop a second 

phase rule that would more likely be able to provide a better balance between 

risks with regulatory requirements. 

75
Response: EPA agrees that an adaptive approach to the UIC GS rulemaking is appropriate. The

Agency plans to use such an approach to ensure that USDWs are protected from endangerment and

meet the potentially 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 pilot 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 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 disagrees that the GS rulemaking needs to be based solely on large-volume projects. While

studying the impact of injecting large volumes of CO2 is important, data on other aspects of GS—

including the buoyancy and corrosivity of CO2 in the presence of water, the potential presence of

impurities in captured CO2, and its mobility within subsurface formations—informed the

rulemaking.

Commenter Name: Ben Yamagata Letter ID: 0227

Commenter Organization: Coal Utilization Research Council Comment ID: 21781

Other EPA Comment Codes and Descriptions: 1200 1.1 General comments about the rulemaking 

Comment: EPA’s proposed rule includes a number of requirements that could create 

significant uncertainty as CCS project developers initiate projects. These 

requirements will serve as barriers to CCS project developers who will need a 

clear idea of their environmental obligations and financial exposures before 

such projects are initiated. In general, we believe that the "adaptive" 

regulatory approach, as set forth in Section III.B. of the Preamble, will lead 

to regulatory uncertainty. Specifically, 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 the 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 initial regulations are 

promulgated. This ability to exercise such broad discretion will discourage 

entities considering CCS projects from moving 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 provide notice and opportunity for comment; 

and to apply any modifications prospectively, allowing projects already 

operating under valid permits to continue to operate pursuant to regulations in 

place 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 proceed 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 regulating CO2 injection for GS will allow regulatory

76
development to proceed and ensure USDW protection 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 the program as necessary

to incorporate new research, data, and information about GS and associated technologies (e.g.,

modeling and well construction). This new information may increase protectiveness, streamline

implementation, or otherwise inform the requirements for GS injection of CO2. Any revisions that

will be made to the GS requirements in the future will go through public notice and comment as

required by the SDWA.

Regarding the comment that projects operating under valid permits should be able to continue to

operate pursuant to regulations in place at the time of permit issuance, EPA notes that changes to the

GS regulation may trigger permit modifications under existing regulations at 40 CFR 144.39(c),

which may trigger public notice and comment procedures under Part 124. EPA adds that the final

GS rule allows the construction of existing Class I, Class 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 meet the requirements at §146.86(a) and

ensure protection of USDWs, in lieu of requirements at §§146.86(b) and 146.87(a).

Commenter Name: Neeraj Gupta Letter ID: 0229

Commenter Organization: Battelle Energy Technology (BET) Comment ID: 21810

Comment: General and Specific Comments on Proposed Regulations 

Adaptive Approach - Overall the proposed policy presents a comprehensive 

framework for geologic sequestration (GS). The adaptive approach seems 

especially useful for enabling early adopters to pursue GS while allowing 

flexibility for adjustments in the future based on technology development and 

lessons learned at individual sites. 

Response: EPA agrees that an adaptive approach to the UIC GS rulemaking is appropriate. The

Agency plans to use such an approach to ensure that USDWs are protected from endangerment and

meet the potentially 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 pilot 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 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.

Commenter Name: Kristin Henry Letter ID: 0242

Commenter Organization: Sierra Environmental Law Program, Sierra Club Comment ID: 23311

Other EPA Comment Codes and Descriptions: 1510 1.2.2.3 Need for additional study 

Comment: There is broad agreement that CCS should proceed by undertaking a few large 

77
demonstration projects in the U.S. the next few years, which must be carefully 

selected and monitored to learn from performance to incorporate into the next 

generation. [FN12] The EPA’s proposed rule should enable selection of the 

lowest-risk, best overall sites for these initial projects, and be adaptive to 

the changes that will occur after knowledge is gleaned from those projects. 

[FN12: IPCC CCS Technical Summary 48 ; Wilson, E., Morgan, M. et al., Regulating 

the Geological Sequestration of CO2, Environmental Science & Technology, Apr. 

15, 2008, at p. 4; Union of Concerned Scientists, Coal Power in a Warming World, 

Oct. 2008, p. 19-21.] 

Response: As described above, EPA agrees that continued research will be integral to development

of GS technology, and is using an adaptive approach to regulating CO2 injection for GS. 

EPA adds that it considered information from laboratory, modeling, and field research as it

developed the requirements for GS wells. In addition to laboratory studies and modeling research

that provide relevant information on GS, the Agency is also involved in collecting and analyzing GS

project data and permit 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 (NETL), and several international projects. In addition to

the information cited in the preamble to the proposed rule, EPA published a Notice of Data

Availability and Request for Comment (NODA) on August 31, 2009 (74 FR 44802), in which the

Agency described the preliminary results of research at three DOE partnership sites (in Escatawpa,

Mississippi; the Aneth Field in Paradox Basin, Southeast Utah; and the Pump Canyon Site, New

Mexico). EPA sought comment on this data and used it to inform the final rule. 

Commenter Name: Kevin Wanttaja Letter ID: 0248

Commenter Organization: Western Energy Supply and Transmission

Associates

Comment ID:

22250

Other EPA Comment Codes and Descriptions: 1250 1.1.1.4 Flexibility is needed (performancebased standards) 

Comment: – Finally, EPA needs to build into this regulation a "learning and adjustment" 

process that gains feedback from implementation of the UIC for CO2 GS rule, and 

establish a periodic review process to make adjustments and corrections to the 

rule based on experienced gained in permitting, operation, and closure of UIC/GS 

wells. A CCS program of the size anticipated 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 the UIC GS rulemaking is appropriate. The

Agency plans to use such an approach to ensure that USDWs are protected from endangerment and

meet the potentially 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 pilot 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. 

78
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 appropriate or necessary.

Commenter Name: Kurt Waltzer Letter ID: 0250

Commenter Organization: Clean Air Task Force Comment ID: 22280

Comment: This precautionary, forward looking statutory purpose and structure authorizes 

EPA also to take an adaptive approach, both in rulemaking and in defining permit 

terms, specifically to direct states to be adaptive in monitoring, tracking, and 

updating permits, in order to reflect lessons learned from experience and from 

monitoring reports. The statute also authorizes EPA to take an adaptive approach 

to the rules themselves. Section 1421(a)(1) states that "any regulation 

[governing underground injection activities] may be amended from time to time." 

[FN17] Whereas, as is the case with EPA’s proposed Class VI rules, regulations 

are established to govern a system on a scale of deployment that has not yet 

been demonstrated [FN18], the preventive and precautionary nature of the UIC statute 

demands a periodic review, assessment, and update of the rule. EPA should, in 

its final rule, declare its intention to undertake such a process. Moreover, our 

Environmental NGO Group recommends that EPA commit itself to issuing a Notice of 

Proposed Rulemaking by no later than an identified date, perhaps in 2020, which 

would formally initiate this process. 

[FN17: 42 U.S.C. § 300h(a)(1).] 

[FN18: Although the practice of injection/GS has been demonstrated at the 

individual project scale.] 

Response: EPA agrees that an adaptive approach to the UIC GS rulemaking is appropriate.

However, the Agency does not feel that in order to use such as approach they need to commit to a

date for a proposed rulemaking. The Agency plans to use an adaptive approach to ensure that

USDWs are protected from endangerment and meet the potentially 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 pilot 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 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.

Commenter Name: Greg Shubel Letter ID: 0284

Commenter Organization: Inter-Tribal Council of Michigan, Inc Comment ID: 25301

Other EPA Comment Codes and Descriptions: 1510 1.2.2.3 Need for additional study 

Comment: The aforementioned deployment phase will not be completed until 2017. ITCMI ESD 

believes all research studies should be completed and the results thoroughly 

understood BEFORE the rule is finalized. 

79
Response: EPA acknowledges the commenter's need for regulatory certainty and believes it has

sufficient data on GS to finalize the rule. However, EPA acknowledges that, because all GS in the

United States is currently associated with pilot projects, there are many unknowns about how GS

projects will unfold and the practicalities of permitting, operating, monitoring, and closing a GS

project. Therefore, EPA agrees that an adaptive approach to the UIC GS rulemaking is appropriate.

The Agency plans to use such an approach to ensure that USDWs are protected from endangerment

and meet the potentially 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 pilot 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 collect and review data on GS projects to determine whether the

appropriate amount and types of information and documentation are being collected, and to

determine if modifications to the requirements are or necessary.

EPA agrees that continued research will be integral to development of GS technology, but disagrees

that the Agency should wait for the DOE pilot studies to be complete before finalizing the GS rule.

EPA believes that establishing a regulatory framework for the future development and deployment

of CCS technology protects USDWs from endangerment and will not impede industry adoption of

CCS. EPA published a Notice of Data Availability and Request for Comment (NODA) 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, New Mexico). EPA has used the data generated to inform the final rule and

will continue to monitor ongoing research.

Commenter Name: George Peridas Letter ID: 0534

Commenter Organization: Natural Resources Defense Council (NRDC) Comment ID: 21454

Comment: As I pointed out, we do have a number of technical comments, which of course, if 

you take them you will make the rule perfect, so we urge you to do that. 

We do believe that some revisions are necessary and I would go briefly through 

some technical points, but the final word on the timing here, there is a trade 

off in my mind between how the rule is written and the need for language to be 

revised in the future. I think some are claiming that the large scale 

injections, some of which might be performed by DOE, will be the catalyst or the 

trigger for major revisions to the rule. I do not think that is necessary. I 

Response: EPA agrees that an adaptive approach to the UIC GS rulemaking is appropriate. The

Agency plans to use such an approach to ensure that USDWs are protected from endangerment and

meet the potentially 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 pilot 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 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.

80
Commenter Name: George Peridas Letter ID: 0534

Commenter Organization: Natural Resources Defense Council (NRDC) Comment ID: 21465

Other EPA Comment Codes and Descriptions: 1380 1.1.3.6 Deployment of GS 

Comment: Climate change will not wait and I think 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 scale and timing. I do not believe that we 

are ready to proceed with wide scale deployment of sequestration all around the 

country. It is something we saw a hundred permit application as soon as rules 

promulgated and I do think this is premature. We are not ready to move in that 

direction. Nonetheless I think by the nature of the beast and the current 

economics of CCS, we will not see that happen. What we are talking about here is 

an initial wave and an initial set of projects that would be permitted and then 

studied 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 projects. 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 overnight. There will be ample time, study 

and reassessments. 

Response: EPA believes that there is a potential that GS may be deployed at a fast pace (e.g., if

climate change legislation provides an incentive for sequestering CO2 or if other climate policies 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 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 pilot projects and other research as it becomes available and enhance

understanding of the technical and administrative aspects of GS deployment, operation, and

technology developments.

81