This comment letter response contains two parts:   

(1) The original submittal from the commenter.

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

Notes about the response letters:

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

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

was assigned a Letter ID that corresponds to the last four digits of the docket number of the

original comment (as posted on www.regulations.gov).

• Each response letter includes: comment text; an EPA‐assigned comment code; and an

individual response. These are described and explained below.  

• The data base contains Comment text from the letters submitted by commenters.  

Many hard copy letters were scanned into electronic format for inclusion in the data

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

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

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

appropriately addressed.

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

Comment ID.  Additionally, one or more Comment Codes (i.e., unique topic area ID) was

assigned to each discrete point raised by a commenter. This information was added to

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

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

construction requirements).  

• Following decisions on the final rule requirements, Individual responses were drafted

by topic area to ensure completeness and consistency of the responses with the final

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

commenter was given a unique response.

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

Each letter response is a compilation of each comment and its individual response,

compiled in the order of the original comment letter.  As a result of this process, there is

repetition in the response text.  The Agency believes this approach ensures completeness

and attention to each comment letter that was submitted.   

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

Responses on each topic area are compiled and are also available in the rulemaking docket.











Letter ID: 0175 

Commenter: Pamela Faggert 

Organization: Dominion 

Letter ID: 0175 Comment ID: 23512 Letter Lines: 73 to 93 

Comment Code: 1000 1. General and Administrative Comments 

Comment: Dominion has participated in the development of industry comments and positions 

with the Edison Electric Institute (EEI) and the Utility Solid Waste Activities 

Group (USWAG), and supports the views expressed therein. Additionally, Dominion 

is a member of the American Gas Association (AGA) and Interstate Natural Gas 

Association of America (INGAA) and shares many of the concerns and opinions of 

these organizations. 

While supportive of the comments of our industry peers and associations, 

Dominion's comments are shaped by several factors unique to Dominion: 

(a) Dominion has substantial coal fired assets in the northeast U.S. where 

geology is less conducive to GS into conventional formations; 

(b) Dominion has extensive underground natural gas storage assets in West 

Virginia, Ohio, Pennsylvania and New York; and, 

(c) Likely target formations for GS in Dominion's regulated territory are 

unmineable coal seams and depleted coal bed methane wells, including enhanced 

gas recovery from coal seams. These target formations, while representing only a 

small fraction of the total US projected storage capacity, are the most viable 

target formation for a signifIcant portion of Dominion's CO2 sources. 

Individual Response: EPA acknowledges that depleted oil and gas reservoirs associated with 

ER operations may be used for CO2 storage and that these sites may be some of the first sites 

where commercial-scale GS is deployed. The rule clarifies that Class VI requirements apply to 

any CO2 injection project (regardless of formation type) when the purpose of the project is longterm storage. Please see the remainder of EPA's responses to this comment, EEI’s comment, 

AGA’s comment, and USWAG’s comment for further details. For additional information on 

EPA's final regulatory approach please see the final rule and the discussion of site-selection 

criteria and target formations for GS in the preamble as well as the rulemaking docket. 

Letter ID: 0175 Comment ID: 23513 Letter Lines: 95 to 106 

Comment Code: 1330 1.1.3.1 Support use of GS in general 

Comment: Guiding Principals 

1
Addressing climate change will require a full portfolio of options for reducing 

greenhouse gas emissions. Dominion believes that carbon capture and storage 

(CCS) is an essential component of any future climate change mitigation policy 

and, accordingly, commends EPA for initiating the rulemaking process. 

Dominion supports the development of clear, flexible, scalable and appropriate 

regulations that will facilitate investment and development of CCS technology 

while assuring appropriate protections against adverse impacts to underground 

sources of drinking water (USDW). Dominion feels that the proposed regulations 

achieve these goals in many respects. 

Individual Response: EPA agrees that GS is one technology in a portfolio of options, including 

energy conservation, efficiency improvements, and the use of alternative fuels and renewable 

energy sources, that could be deployed to reduce CO2 emissions. EPA recognizes the importance 

of providing clear, flexible, scalable, and appropriate regulations, and believes that the GS 

regulation will provide certainty to industry and the public by providing consistency in 

requirements across the U.S. and transparency about what requirements apply to owners or 

operators. 

Please see the remainder of EPA’s responses to this comment for further details. For additional 

information on EPA’s final regulatory approach, please see the final rule and preamble as well as 

the rulemaking docket. 

Letter ID: 0175 Comment ID: 23514 Letter Lines: 112 to 128 

Comment Code: 1200 1.1 General comments about the rulemaking 

Comment: Promotion of CCS 

The Agency rightly acknowledges that CCS is a key climate change mitigation 

technology, and the proposed rules should support its development. The UIC rules 

should be designed to facilitate, and not hinder, the successful commercial 

scale deployment of CCS. As such the rulemaking necessitates a host of 

regulatory approaches: recognition that early adopters are likely to be EOR 

operators; grandfathering of existing wells which facilitates development of GS 

wells; appropriate characterization of CO2 and potential risks; avoidance of 

unnecessary stigmatization of GS; a recognition of the diversity of target 

formations (including especially unmineable coal seam formations); an 

appreciation for the consequences of public perception; avoidance of one-size 

fits-all approaches; and regulatory certainty through limits and guidelines to 

Directors' discretion. Furthermore, a successful CCS regime requires the 

avoidance of conflicts to the extent possible. Accordingly, GS should be 

promoted at sites where it has minimal risk to other uses of underground 

formations, such as natural gas storage. 

Individual Response: EPA acknowledges the comment. Please see the remainder of EPA's 

2
responses to this comment for further details. For additional information on EPA's final 

regulatory approach, please see the final rule and preamble as well as the rulemaking docket. 

EPA clarifies that the intent of the GS rule is not to promote or encourage the use of GS; rather, 

its purpose is to ensure consistency in permitting underground injection of CO2 at GS operations 

across the United States and provide requirements to prevent endangerment of USDWs in 

anticipation of the eventual use of GS to reduce CO2 emissions. 

Letter ID: 0175 Comment ID: 23515 Letter Lines: 130 to 138 

Comment Code: 1250 1.1.1.4 Flexibility is needed (performance-based standards) 

Comment: Flexibility 

EPA states throughout the proposal that flexibility in the application of the 

rule is essential to balancing the protection of USDW against the need to 

facilitate CCS development and commercialization. Accordingly, Dominion urges 

EPA to recognize that no two GS sites are identical and that requirements that 

may be appropriate for one site may be prohibitive for another site. While 

directorial discretion is a useful mechanism to ensure flexibility in the Final 

Rule, such discretion must be clearly defined and limited. 

Individual Response: EPA agrees that permitting decisions for GS wells should be based on 

site-specific factors. The GS rule requires owners or operators to submit, and Directors to 

consider, extensive site-specific data, specified at §146.82, to demonstrate that a site is suitable 

for GS. Additionally, many of the permit requirements for GS wells are established through 

individualized site-specific plans for AoR and corrective action, testing and monitoring, and 

injection well plugging and post-injection site care and site closure. EPA adds that the final GS 

rule includes a balance of specific criteria to be met by the owner or operator and areas of 

Directorial discretion and considerations for how that discretion would be exercised. The Agency 

believes this balance allows for GS projects to be designed and permitted to address the unique, 

site-specific aspects of each 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 authority (primacy) for GS Class VI wells under Section 1422 of SDWA, 

as well as the technical and administrative issues on developing GS regulations that are the 

equivalent of minimum federal criteria and requirements. The guidance will describe areas of 

Directorial discretion and considerations for how that discretion would be exercised. This 

guidance will be available on EPA’s website at 

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

Letter ID: 0175 Comment ID: 23516 Letter Lines: 140 to 150 

Comment Code: 1250 1.1.1.4 Flexibility is needed (performance-based standards) 

3
Comment: Adaptability 

The Agency should strive to anticipate future statutory and regulatory 

developments in the climate change arena so that any rulemaking has a reasonable 

chance of facilitating such developments. EPA can and should consider how its 

UIC rulemaking will fit with foreseeable features of potential future regimes 

and how rules can be drafted to complement such features to the extent possible. 

Additionally, because it is difficult to know at this point what methods or 

technology will be developed for injection and long-term storage of CO2, coupled 

with projected demands for capacity, EPA should not prematurely preclude the use 

of specific types of sites or methods for Class VI CO2 injection. 

Individual Response: EPA is using an adaptive approach to regulating GS under the UIC 

Program. Even after finalization of the GS regulation, EPA plans, every six years, to collect and 

review project data on GS research projects to determine whether the appropriate amount and 

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

modifications to the requirements are appropriate or necessary. 

Letter ID: 0175 Comment ID: 23517 Letter Lines: 152 to 162 

Comment Code: 2020 1.5.1 Support Class VI designation 

Comment: Specific Comments on the Proposal 

1. Creation of Class VI Category 

Dominion supports the creation of a new class of injection wells for CO2 

injection and storage. Establishing a new Class VI class enables appropriate 

regulations based on the unique characteristics of CO2 sequestration, namely the 

buoyancy, corrosivity, and anticipated volumes. Including CO2 GS in the existing 

Class I, Hazardous Waste regulations would unnecessarily stigmatize CCS, 

creating public perception problems and would be inappropriate for protection of 

USDW. 

Individual Response: 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 plugging, post-injection site care, and site closure 

of GS wells that directly address issues unique to the nature of large-scale CO2 injection for GS. 

EPA also agrees that Class I regulations are not appropriate to fully address GS wells and would 

not necessarily be protective of USDWs. 

Letter ID: 0175 Comment ID: 23518 Letter Lines: 164 to 171 

4
Comment Code: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83) 

Comment: 2. Siting 

Dominion agrees that proper site selection is critical to a successful GS 

project. Appropriate siting can minimize or eliminate risk of potential threats 

to USDW that GS may pose. However, several of the contemplated requirements and 

restrictions in the Dominion Comments on Proposed Regulation of CO2 Injection 

Wells proposal are unnecessary for the protection of USDW and could discourage 

the development of CCS. 

Individual Response: 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 disagrees that any of these protective requirements are unnecessary, and clarifies that 

waiving any of the requirements would not be acceptable. The GS regulation allows flexibility 

where appropriate. Certain requirements (e.g., the need to characterize additional confining 

layers) are at the Director's discretion (§146.83(b)). 

Letter ID: 0175 Comment ID: 23519 Letter Lines: 173 to 194 

Comment Code: 4324 2.4.4.1.2 Comments opposed to requiring injection below the lowermost 

USDW 

Comment: a. Limitations on Receiving Formations above the lowermost USDW 

The proposal contemplates injection only below the lowermost USDW. Such a 

prohibition is troublesome for several reasons. First, it is unnecessary for the 

protection of USDW. There are numerous other safeguards affording necessary 

protections of USDW when demonstrated appropriately in the permitting process 

(e.g. injection zone characteristics, geology, modeling, confining zone, depth, 

fluid composition, etc). Secondly, such a categorical exclusion may 

unnecessarily eliminate vast storage formations that may be the only 

geographically feasible GS site for some sources of CO2 (e.g. unmineable coal 

seams, experimental formations, etc). Third, it is likely to hamper commercial 

development of CCS, as EOR wells are likely the early adopters of GS wells and 

some EOR wells would be excluded from transitioning to Class VI wells with such 

a prohibition. Lastly, it is likely to create unfavorable public perception 

issues if GS is treated so categorically similarly to Class I Hazardous Waste 

wells. 

5
There should be no blanket prohibition against injection into any 

approved geologic zone even if above the lowermost USDW. There are 

circumstances where this may be perfectly appropriate and safe. The 

decision needs to be site specific and based on evaluation of local 

geology and other factors. 

Individual Response: 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. 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. 

EPA agrees that proper siting, monitoring, and containment capacity are critical elements of 

Class VI injection for GS. However, the Agency also believes that injection into non-USDW 

formations above and between USDWs presents unique challenges related to movement of CO2 

in the subsurface, which requires a unique approach to ensure that USDWs are protected. 

Therefore, the Agency believes that additional requirements are appropriate and necessary for 

wells that would inject into non-USDWs above and between USDWs. 

Letter ID: 0175 Comment ID: 23520 Letter Lines: 196 to 212 

Comment Code: 3120 2.1.2 Need to identify additional confining and containment zones 

(seeking comment) 

Comment: b. Requirements for Secondary Containment 

The Agency is considering granting discretion to the Director to require 

"additional zones that will impede vertical fluid movement..." Such broad 

discretionary authority is unnecessary for the same reasons that limitations of 

injection to formation below the lowermost USDW are unnecessary. This 

discretionary authority is likely to have a negative affect on GS into 

unmineable coal seams and for storage through existing EOR wells. In the event 

6
the Agency elects to retain this authority, we urge EPA to modify the proposal 

to include clear guidelines in order to provide some amount of certainty for CCS 

operators and investors. Additionally, clear guidelines for exercising 

requirements for secondary containment would safeguard against what is 

discretionary authority on paper from becoming default requirements in practice. 

Secondary confinement should not be a requirement. Such a requirement 

would eliminate good and sound storage sites and reduce ultimate 

capacity of the country to store CO2. 

Individual Response: EPA retains the requirement to identify additional containment/confining 

zones, if required by the Director, as proposed (e.g., §146.83(b)). The Agency's decision is 

supported by commenters representing states, water associations, and an electric utility who 

assert that these requirements (at §146.83(b)) promote a flexible, risk-based, site-specific 

approach to characterizing and permitting a site for GS projects. 

The Agency believes that providing the Director discretion will allow consideration of a range of 

sites for GS, based on site-specific conditions and ensure USDW protection. EPA believes that 

requiring appropriate site characterization by the owner or operator (under §146.82) and 

providing an appropriate degree of flexibility to the Director to evaluate site-specific geologic 

data will afford the greatest protection of USDWs from endangerment. 

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 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. EPA expects that this guidance will 

assist permit writers in making an objective decision about requiring additional confining layers. 

The guidance can be found on EPA’s website at 

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

Letter ID: 0175 Comment ID: 23521 Letter Lines: 214 to 244 

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

ownership 

Comment: c. Impact of GS well siting on Underground Natural Gas Storage 

As a general matter, EPA should ensure that Class VI permits not inappropriately 

interfere with other pre-existing subsurface interests and operations. 

Dominion's interest in the rulemaking is from the perspective of both an 

owner/operator/contractor of CCS and a potentially affected party as an operator 

of an extensive network of underground natural gas storage. The sole 

responsibility of the UIC Program is to provide protections for existing and 

future USDW. Little protections are afforded for other underground resources, 

7
however. The rulemaking unambiguously leaves these concerns to the individual 

states, irrespective of primacy status. The rulemaking's silence with regard to 

protections for underground natural gas storage formations is cause for concern 

to the natural gas industry. 

Gas storage operators have particular expertise regarding their natural gas 

storage fields, and can help prevent problems if EPA helps to ensure their 

participation in the process of the site evaluation and construction of GS wells 

in natural gas storage fields. The Agency should authorize the Director to 

ensure the coordination between natural gas storage operators and GS well 

owners/operators in circumstances where the GS construction will occur in 

natural gas storage fields. Such coordination can involve, for example, 

obtaining input from the natural gas storage operators on the unique 

circumstances associated with the natural gas storage field where the GS well 

will be constructed. To assist in this process, natural gas storage field 

operators should have ready access to GS well records, well logs and cementing 

records for any GS construction activity that occurs in a natural gas storage 

field. 

EPA should authorize Directors to ensure coordination between natural 

gas storage operators and GS well owners/operators in circumstances 

where the GS construction will occur in natural gas storage fields. 

Individual Response: EPA clarifies that pore space ownership and surface and subsurface 

property and mineral rights are outside of the scope of the Class VI GS rulemaking. EPA 

clarifies that these issues are under the purview of states and any of these issues, as they relate to 

GS, will need to be addressed though state regulations. The Class VI GS rule is designed to 

ensure protection of USDWs from endangerment through proper permitting, siting, well 

construction, operation, monitoring, and closure of Class VI GS projects. 

As part of the permit application process, prospective operators of Class VI GS wells must 

submit data on other activities subject to environmental permitting (e.g., oil or gas fields), mines, 

and a tabulation of all wells in the area of review. This information, including data on any other 

injection or production activities in the area would be taken into consideration by the Director in 

evaluating the appropriateness and safety of the proposed site. 

Letter ID: 0175 Comment ID: 23522 Letter Lines: 246 to 276 ; 425 to 427 

Comment Code: 2163 1.6.3.1 Comments in favor of injection into unmineable coal seams 

Comment: d. Sequestration in Unmineable Coal Seams 

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". 

8
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. 

Individual 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. 

9
Letter ID: 0175 Comment ID: 23523 Letter Lines: 278 to 294 

Comment Code: 3530 2.2.3.1 AoR reevaluation frequency (seeking comment) 

Comment: 3. Area of Review 

Unlike existing UIC classes of wells, the Area of Review (AoR), the area within 

which all pre-existing wells must be identified and studied to determine whether 

they have been properly completed or plugged, will be determined on a sitespecific basis using computational fluid flow models. Whereas Dominion supports 

the site-specific determination for AoR, we urge EPA to eliminate the arbitrary 

10-year maximum between periodic reevaluation of the AoR. Tying reevaluation to 

the triggering of appropriate circumstances will provide equivalent protection 

of USDW while also ensuring that those projects posing greater relative risks 

receive greater scrutiny through more stringent reevaluation requirements while 

those projects posing fewer relative risks are relieved of costly regulatory 

burdens. 

The Agency should avoid requiring an arbitrary 10 year maximum between 

periodic reevaluations of the AoR and instead should rely on site 

specific circumstances to determine periodic review schedules. 

Individual Response: EPA disagrees that the requirement at §146.84(e) for a periodic AoR 

reevaluation is arbitrary. EPA proposed the ten-year frequency based on input from stakeholders 

and experts at the technical workshops on "Geological Considerations and AoR Studies" and 

"Modeling and Reservoir Simulation for Geologic Carbon Storage." EPA also requested 

comment on the ten-year frequency. In the preamble to the proposed rule, EPA identified 

benefits to periodically reevaluating the AoR, including allowing refinement to the AoR 

delineation based on real-world conditions and monitoring results, increasing confidence in the 

modeled predictions, and targeting monitoring in those areas subject to the greatest potential risk. 

Based on the comments received (including those by water associations, an energy company, 

associations, industries, states, and environmental groups), EPA has changed the minimum 

frequency for the AoR reevaluation from 10 years to at least every 5 years. EPA believes that 

this revised frequency addresses commenters' concerns about the inherent uncertainties in 

modeling CO2 movement, the emerging nature of GS technology, risk-based targeting of 

monitoring activities, and the unique nature of CO2 GS. 

EPA adds that the GS rule at §146.84(e) requires the AoR reevaluation, along with the iterative 

process of developing and executing the various plans required of GS well operators (e.g., for 

AoR and corrective action, testing and monitoring, injection well plugging, post-injection site 

care, and emergency and remedial response) instead of period permit renewals (e.g., of 10 years 

for Class I wells). EPA believes the iterative process and subsequent reevaluations of the AoR 

and corrective action, testing and monitoring, and emergency and remedial response plans are 

preferable to a periodic permit reapplication and review of the entire permit because they focus 

10
time and resources to the most critical aspects of the permit. Additionally, AoRs reevaluated 

after at least every 5 years of injection will provide data on GS projects to inform EPA's adaptive 

rulemaking approach. 

Letter ID: 0175 Comment ID: 23524 Letter Lines: 296 to 303 

Comment Code: 3630 2.2.4.1 Comments in favor of allowing phased corrective action 

Comment: Dominion supports the requirement to conduct corrective action within the AoR 

provided the Director can authorize phased corrective action when warranted 

based on site specific performance and conditions. As with other discretionary 

authority proposed, there should be requirements establishing bounds for 

exercising such discretion to avoid arbitrary application of such authority. 

Directorial discretion should be subject to guidelines as to when phased 

corrective action should NOT be permitted. 

Individual Response: EPA agrees that phased corrective action may provide many benefits to a 

project including, but not limited to, spreading the burden of cost, avoiding delays in project 

start-up, allowing for use of future, improved corrective action techniques and addressing 

unanticipated changes in the movement of the CO2 plume or pressure front. EPA believes that 

the phased corrective action approach is appropriate for GS projects, and has retained it at 

§146.84(b)(2)(iv) in the final GS regulation. 

EPA does not agree that a phased approach to corrective action should be available to all owners 

or operators, because phased corrective may not be appropriate at all GS sites. EPA believes that, 

given the wide range of conditions at GS sites, the Director is in the best position to make 

decisions about the appropriateness of phased corrective action based on his or her knowledge of 

the local geologic and site conditions. EPA is developing guidances for states that help to 

describe the technical and administrative issues a state may need to consider when developing 

GS regulations that are the equivalent of minimum federal criteria and requirements; this 

guidance will provided recommended approaches for Directors to exercise discretion. The 

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

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

Letter ID: 0175 Comment ID: 23525 Letter Lines: 305 to 312 

Comment Code: 5240 2.8.2.2 Post injection timeframe (seeking comment) 

Comment: 4. Post-injection Site Care 

The proposed rule's post injection site care (PISC) period of 50 years, subject 

to Director discretion, is arbitrary and unnecessary. The PISC should be set 

11
based on a site-specific performance-based approach. 

The PISC period should be based not on an arbitrary default but on a 

site specific performance-based approach. 

Individual Response: EPA disagrees that a post-injection site care timeframe of 50 years is 

arbitrary. In determining the post-injection site care-timeframe for the proposed regulation, EPA 

reviewed industry reports, existing environmental programs, and initial GS research studies. EPA 

provided a synthesis of pertinent results from GS modeling studies in the preamble to the 

proposed regulation. Further explanation of this analysis was included in an EPA-prepared 

background document that is available in the federal docket, titled "Computational Modeling of 

Underground Injection of Carbon Dioxide for Determination of Area-of-Review and Potential 

Risk to Underground Sources of Drinking Water." Based on review of these studies, modeling 

results indicate that the CO2 plume stabilization may occur on the timeframe of 10-100 years 

after the cessation of injection. EPA believes that a 50-year default post-injection site care 

timeframe is a reasonable midpoint for most GS projects and available data, including data 

submitted by commenters, do not support a different default timeframe, and has retained this in 

the final regulation. 

To address concerns that, in some situations, it can be demonstrated in less than 50 years that the 

plume and pressure front no longer pose a risk of endangerment to USDWs, the GS regulation 

offers owners or operators flexibility regarding the duration of the PISC timeframe by: (1) 

allowing the Director discretion to shorten or lengthen the PISC timeframe during the postinjection period based on site-specific data, pursuant to requirements at §146.93(b); or (2) 

affording the Director discretion to allow a Class VI well owner or operator to demonstrate, 

during the permitting process based on substantial data, that an alternative PISC timeframe may 

be appropriate if it ensures non-endangerment of USDWs pursuant to requirements at 

§146.93(c). 

EPA believes however, that to ensure USDW protection from endangerment, a default timeframe 

for post-injection site care will be necessary in most cases. The default 50 year post-injection site 

care timeframe represents a reasonable and protective monitoring period based on a review of 

research studies, industry reports, and existing environmental programs, and evaluation of public 

comments. 

EPA believes that a default post-injection site care timeframe of 50 years, with flexibility to 

adjust the timeframe for a limited number of GS projects during the permitting process where 

substantial data exists to demonstrate that an alternative timeframe would be protective of 

USDWs, or based on data collected during the PISC period, is appropriate to address the range of 

sites where GS is anticipated to occur, to accommodate site-specific circumstances and various 

geologic conditions, and addresses commenters’ concerns, while ensuring USDW protection. 

Both approaches will utilize site-specific data, and be based on pressure monitoring and USDW 

impacts. 

Letter ID: 0175 Comment ID: 23526 Letter Lines: 314 to 327 

Comment Code: 5430 2.9.1 Comments on proposed financial responsibility requirements (40 

12
CFR 146.85) 

Comment: 5. Financial Assurance 

The proposal would require that permittees demonstrate, at the time of project 

permitting, financial assurance for activities including injection, corrective 

action, well plugging and closure, and activities throughout the PISC period - 

as well as for emergency and remedial response activities to address movement of 

formation or injection fluids that may endanger USDW. These proposed financial 

assurance requirements, which exceed those currently in place even for injection 

of hazardous wastes, raise significant concerns from the perspective of 

promoting CCS development. The Agency should also consider, as mentioned in the 

preamble, a phased or staged approach to financial assurance requirements. 

Dominion urges the Agency to allow for phasing of financial assurance 

and consider capping assurances in order to facilitate CCS development. 

Individual Response: In the final rule, owners or operators must demonstrate, with their permit 

application, adequate financial responsibility for all required Class VI activities, including 

plugging and post-injection site care, per §146.85(a). However, owners or operators may choose 

from a variety of financial instruments to meet their financial responsibility obligations under the 

rule, provided the Director determines that the operator's proposed financial responsibility 

demonstration is adequate to protect USDWs from endangerment, which means the ability of the 

owner or operator to pay for each activity for which financial responsibility must be 

demonstrated, including corrective action on wells in the AoR, injection well plugging, PISC and 

site closure, and emergency and remedial response throughout the life of the project. The final 

GS rule specifies at §146.85(a)(1) the permitted types of financial responsibility instruments. See 

the final rule and preamble for further discussion of EPA's final approach to financial 

responsibility. 

EPA believes that the demonstration at the time of permit application is necessary to ensure that 

financial resources are available to prevent the endangerment of USDWs in the event that the 

owner or operator experiences financial difficulties at any time during the life of the GS project. 

In addition, financial responsibility will need to be reevaluated prior to well plugging or site 

closure, or at any other time deemed appropriate by the Director, for example, following AoR 

reevaluations. See the final rule and preamble for further discussion of EPA's final approach to 

financial responsibility. 

EPA disagrees that the requirements equate GS wells with Class I hazardous waste wells; rather, 

the financial responsibility requirements for Class VI wells are tailored to account for the unique 

nature of the long term GS of CO2, while providing flexibility for site specific implementation. 

EPA adds that the purpose of the GS rule is not to incentivize or promote GS; rather it is to 

ensure that where GS is deployed, it is done in a manner that ensures USDW protection from 

endangerment. 

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Letter ID: 0175 Comment ID: 23527 Letter Lines: 329 to 336 

Comment Code: 5460 2.9.2 Comments on transfer of liability for long-term care 

Comment: While EPA's authority with regard to issues of liability transfers for CCS 

projects is limited, we encourage the Agency to consider that liability 

transfers may be accomplished under other laws and to examine closely how the 

UIC rules can take such provisions into account. An option that is within the 

SDWA's jurisdiction may be to include a provision indicating that where a third 

party assumes a permittee's regulatory obligations, the permittee is deemed to 

have satisfied applicable financial assurance requirements, which can then be 

terminated for the original permittee. 

Individual Response: Under the final GS rule, once an owner or operator has met all regulatory 

requirements under Part 146 for Class VI wells and the Director has approved site closure 

pursuant to requirements at §146.93, the owner or operator will generally no longer be subject to 

enforcement for regulatory noncompliance. Furthermore, their financial instrument as required 

under §146.85 will be released if it was not used. However, even if a site closure is approved 

under §146.93, an owner or operator may be held liable for regulatory noncompliance (including 

violation of 40 CFR 144.12) in certain circumstances. For example, an owner or operator may be 

held liable for regulatory noncompliance even after site closure was approved if the Director 

relied on erroneous information (e.g., erroneous modeling data) provided by the owner or 

operator when approving site closure. 

Separate from EPA’s authority to enforce regulatory compliance, an owner or operator may be 

subject to a §1431 response order even after proper site closure is approved under §146.93. 

Under §1431 the Administrator may require an owner or operator to take necessary response 

measures if he or she receives information that a contaminant is present or is likely to enter a 

public water system or an USDW, which may present an imminent and substantial endangerment 

to the health of persons, and the appropriate State and local authorities have not acted to protect 

the health of such persons. The action may include issuing administrative orders or commencing 

a civil action for appropriate relief against the owner or operator of a Class VI well. If the owner 

or operator fails to comply with the order, they may be subject to a civil penalty for each day in 

which such violation occurs or failure to comply continues. 

The Agency clarifies that Class VI well permits may be transferred to another owner or operator 

pursuant to §144.38 whereby generally all other regulatory responsibilities are transferred to that 

new owner and operator, which includes all potential liabilities associated with meeting the 

requirements of that permit. Please see further clarification on the issue of long term liability in 

the preamble of the final rule. 

Furthermore, after site closure an owner or operator may remain liable under tort and other 

remedies, or under other federal statutes including, but not limited to, Clean Air Act, 42 U.S.C. 

§§ 7401-7671; CERCLA, 42 U.S.C. § 9601-9675; and RCRA, 42 U.S.C. § 6901-6992. EPA 

does not have authority to transfer SDWA or other legal liability for Class VI wells to the State 

14
or federal government or a third-party fund. See the final rule preamble for further discussion of 

EPA's final approach. 

Letter ID: 0175 Comment ID: 23528 Letter Lines: 338 to 344 

Comment Code: 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: 6. Transitioning Existing Permitted Wells 

The Final Rule should recognize that EOR and EGR wells are the most likely to be 

utilized for GS by early adopters of commercial sequestration. 

The Agency should facilitate the use of existing EOR/EGR wells for 

purposes of GS, provided that they ensure adequate protection of USDW. 

Individual Response: EPA recognizes that the oil and gas industry has decades of experience 

injecting CO2 for the purpose of ER, and that sites used for EOR may be among the first GS 

sites. EPA also agrees that many Class II 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). 

EPA is developing guidance on transitioning permits from Class II to Class VI. The guidance 

will assist Directors in determining whether an injection project should be transitioned from 

Class II where the primary purpose is oil and gas production to Class VI where the primary 

purpose is long-term storage of large volumes of CO2. The guidance describes the methods 

available for the Director to evaluate changes in risk to USDWs from projects, and 

recommended approaches the Director may use to evaluate 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. 

Letter ID: 0175 Comment ID: 23529 Letter Lines: 346 to 359 

Comment Code: 1630 1.3.3 RCRA/hazardous waste issues (seeking comment) 

Comment Code: 1640 1.3.4 CERCLA issues (seeking comment) 

Comment: 7. Interaction of CO2 with RCRA and CERCLA 

It is essential that the Agency resolve key policy and legal uncertainties 

regarding the interaction of the Resource Conservation and Recovery Act ("RCRA") 

and the Comprehensive Environmental Response, Compensation, and Liability Act 

("CERCLA or Superfund") with Class VI injection activities. EPA's proposed rule 

15
refers to the potential presence of unknown or unidentifiable hazardous 

constituents in various streams. See 73 Fed. Reg. at 43,503-04. This leaves 

Class VI permittees with little certainty as to which constituents, whether 

present in the CO2 stream itself, in the receiving underground soil and aquifer, 

or via some reaction between the two, might subject the permittee to liability 

under RCRA or CERCLA. This regulatory uncertainty will make it difficult for CCS 

to attract the investment necessary to ensure its viability as a climate 

mitigation strategy. 

Individual Response: The GS rule does not set generic purity standards for CO2 injectate 

streams (e.g., a percent CO2). Instead, the GS rule addresses the quality and quantity of 

impurities by requiring owners or operators to submit information on the source of the CO2 and 

its physical and chemical properties. Specifically, the GS rule requires the owner or operator to 

submit data about the site, including an analysis of the chemical and physical characteristics of 

the CO2 stream, as required at §146.82(a)(7)(iv), and information on the compatibility of the 

CO2 stream with fluids in the injection zone and minerals in both the injection and the confining 

zones and the materials used to construct the well, per §146.82(c)(3). This information can help 

the Director determine the potential for geochemical reactions between the injectate (CO2) and 

the host geologic formations, which could result in the plugging of pore spaces or the dissolution 

of formation minerals. 

With respect to RCRA, EPA received many comments regarding the applicability of the RCRA 

regulations and statute to CO2 streams that are geologically sequestered under the final Class VI 

UIC well requirements. As a result, EPA has decided to initiate a separate proposed rulemaking 

specifically to examine the issue of RCRA applicability to CO2 streams being geologically 

sequestered, including the possible option of a conditional exemption from the RCRA 

requirements for CO2 GS in Class VI wells. EPA will consider these comments as part of its 

development of that proposal. The Agency will consider issues particular to RCRA in the context 

of that separate rulemaking, and recommends that the commenter read that proposed rule when it 

is published. The Agency notes that commenters who wish to submit comments on the RCRA 

proposal will need to do so during the comment period for that rule. Finally, EPA also notes that 

the final GS rule, which adds new regulations for Class VI wells under the Safe Drinking Water 

Act (SDWA), is not making any changes to the RCRA regulations. 

CO2 itself is not listed as a hazardous substance under CERCLA however, the CO2 stream may 

contain a listed hazardous substance (such as mercury) or may mobilize substances in the 

subsurface that could react with ground water to produce listed hazardous substances (such as 

sulfuric acid). Whether such substances may result in CERCLA liability from a sequestration 

facility depends entirely on the composition of the specific CO2 stream and the environmental 

media in which it is stored (e.g., soil or ground water). CERCLA exempts from liability, under 

CERCLA section 107, 42 U.S.C. 9607, certain “federally permitted releases” as defined in 

CERCLA, 42 U.S.C. 9601(10). Class VI permits will need to be carefully structured to ensure 

that they prevent potential releases from the well which are outside the scope of the Class VI 

permit. 

16
Letter ID: 0175 Comment ID: 23530 Letter Lines: 361 to 364 

Comment Code: 1630 1.3.3 RCRA/hazardous waste issues (seeking comment) 

Comment: To the extent there is any possibility that CO2 injection operations could be 

subject to RCRA controls, EPA should exempt such activities under the wellestablished "contingent management" concept given that the UIC permit will 

ensure that the injected material is not mismanaged. 

Individual Response: EPA agrees that any requirements for the CO2 stream should be clearly 

identified. As described above, EPA has decided to initiate a separate proposed rulemaking 

specifically to examine the issue of RCRA applicability to CO2 streams being geologically 

sequestered, including the possible option of a conditional exemption from the RCRA 

requirements for CO2 GS in Class VI wells. 

Letter ID: 0175 Comment ID: 23531 Letter Lines: 366 to 372 

Comment Code: 1640 1.3.4 CERCLA issues (seeking comment) 

Comment: EPA also should incorporate in its Final Rule application of CERCLA's "federally 

permitted release" exemption to Class VI permits, which would minimize the 

potential for CERCLA liability attaching to Owners or Operators of Class VI 

injection wells. This would mean including in the scope of the Class VI permit 

all CERCLA hazardous constituents likely to be contained in the CO2 stream, 

including those generated during capture and transport, as well as any that 

could be formed in the injection zone. 

Individual Response: The Agency thanks the commenter for their comments regarding the 

CERCLA exemption for federally-permitted releases. EPA notes that the GS rule is not 

promulgated under CERCLA, therefore the applicability and interpretation of that statute are 

outside the scope of this rulemaking and will not be determined under the SDWA or the terms of 

the GS rule, but rather according to the CERCLA statute itself and any implementing regulations 

that may apply. 

Letter ID: 0175 Comment ID: 23532 Letter Lines: 374 to 394 

Comment Code: 1630 1.3.3 RCRA/hazardous waste issues (seeking comment) 

Comment Code: 1640 1.3.4 CERCLA issues (seeking comment) 

Comment: Further, EPA already has ample civil and criminal enforcement authority under 

the SDWA to address violations of UIC permits, including the ability to impose 

fines of up to $32,500 per day in civil penalties. This authority thus provides 

a significant and independent means of addressing environmental contamination. 

Finally, EPA should support legislative solutions to ensure companies employing 

17
CCS technologies are assured of reasonable liability protections. While CO2 is 

not listed as a hazardous substance under CERCLA, statutory exemptions under 

both RCRA and CERCLA for a clearly defined set of CO2 injection streams could be 

an appropriate device for mitigating liability concerns. Or, a more tailored 

approach to limiting the scope of RCRA and CERCLA liability for certain types of 

CCS projects could be proposed. 

In order to effectively promote CCS as a viable climate mitigation 

strategy, legal uncertainties surrounding potential CERCLA and RCRA 

liability associated with GS wells must be addressed. To this end, EPA 

should employ RCRA's "contingent management" concept and CERCLA's 

"federally permitted release" exemption as regulatory means to limit 

potential liability and uncertainty. In addition, EPA should advocate or 

support legislative solutions to limit Class VI permittee liability 

under these statutes. 

Individual Response: EPA thanks the commenter for their suggestions and clarifies that any 

comments related to supporting legislative changes to any environmental statutes are outside the 

scope of this rulemaking. Changes to the RCRA and CERCLA statutes are outside the scope of 

the GS rulemaking under the SDWA. EPA agrees that any requirements applicable to CO2 

injectate should be clearly identified to the public and to the regulated community. As described 

above, with respect to RCRA, EPA has decided to initiate a separate proposed rulemaking 

specifically to examine the issue of RCRA applicability to CO2 streams being geologically 

sequestered, including the possible option of a conditional exemption from the RCRA 

requirements for CO2 GS in Class VI wells. 

Letter ID: 0175 Comment ID: 23533 Letter Lines: 396 to 408 

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

ownership 

Comment: 8. Other Issues Outside the Scope of the Rulemaking 

An area of concern to the gas storage industry is the expansion of the UIC 

program. To date, the injection of hydrocarbons for purposes of storage has been 

excluded from federal regulation under the UIC program. If EPA sees fit to 

establish a new category of well for the purpose of injecting CO2 for storage, 

it should be made clear that this program will not affect storage of natural 

gas. This concern is more pronounced as the industry expands its use of CO2 as a 

base gas for underground storage of natural gas. 

The establishment of a new class of well for geologic sequestration of 

CO2 should not include expanding the UIC program generally to 

incorporate underground natural gas storage. 

Individual Response: EPA clarifies that the Class VI GS requirements apply only to wells that 

18
19

are injecting CO2 into the subsurface for the purpose of GS, and not to natural gas storage 

operations. EPA clarifies that developing specific requirements for natural gas storage operations 

is out of the scope of the UIC program's authority. However, 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. 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 (§ 124.10(c)(1)(xi)). EPA expects that these agencies will inform the Director of any 

existing natural gas storage facilities around the proposed Class VI GS site and that the Director 

will take this information and the data on wells in the AoR into consideration when deciding 

whether to grant a permit for the Class VI well.