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.
1

December 18, 2008

Environmental Protection Agency

Water Docket

Mailcode 2822T

1200 Pennsylvania Avenue

Washington, DC 20460

Re: Docket number EPA-HQ-OW-2008-0390

Comments by the CCS Reg Project on proposed EPA rule: Federal Requirements Under

the Underground Injection Control (UIC) Program for Carbon Dioxide (CO2) Geologic

Sequestration (GS) Wells (73 FR 43491-43541, July 25 2008)

Introduction

1. These comments are submitted on behalf of the CCS Reg Project, a two-year research 

effort with the objectives of: designing and facilitating the rapid adoption of a U.S.

regulatory environment for the capture, transport and deep geological sequestration

(GS) of carbon dioxide (CO2); and, ensuring that carbon capture and sequestration 

(CCS) will be done in a manner that is safe, environmentally sound, affordable,

compatible with evolving international carbon-control regimes (including emissions

trading) and socially equitable.

2. The CCS Reg Project is anchored in the Department of Engineering and Public Policy 

at Carnegie Mellon University. Other members of the project team are located at the

Hubert H. Humphrey Institute of Public Affairs at the University of Minnesota, the

Institute for Energy and the Environment at the Vermont Law School, and the

Washington, DC law firm of Van Ness Feldman. Questions regarding these

comments should be directed to project manager Dr. Sean McCoy at 412-268-5489.

3. Primary funding for the CCS Reg Project comes from the Doris Duke Charitable

Foundation. More information about the CCS Reg Project can be found at

http://www.ccsreg.org/index.html.

4. The CCS Reg Project has produced an interim report framing the issues we believe

must be considered if CCS is to be safely and effectively developed. This report

(draft version attached) lays out options for legal and regulatory approaches for CCS.

Over the next 12 months, the CCS Reg Project will complete and publish a final

report that will include specific recommendations and suggestions for possible new

legislative authority.

5. Contributors to the CCS Reg Project, and to these comments, are listed in the attached 

report. Opinions expressed in the report, and in these comments, are those of the

individual contributors and may not represent the views of the institutions with which 

they are affiliated.
2

Overarching issues and concerns

6. We applaud EPA’s work toward developing regulations for GS. It is urgent that the

U.S. moves forward with deployment of CCS technologies: EPA’s effort to write

rules for GS wells incorporating sound scientific and technical knowledge contributes

to creating a regulatory framework that ensures that GS will be done in a manner that

is safe and environmentally sound. The speed with which EPA drafted these rules,

and the inclusiveness of the rulewriting process, are well matched to the urgency and

broad interest in the problem.

7. EPA’s laudable efforts notwithstanding, we believe the Safe Drinking Water Act

(SDWA) does not provide adequate authority to comprehensively regulate GS.

Because the statutory authority for the UIC Program derives from the SDWA, the

proposed rule is unable to address key issues that must be resolved for commercialscale GS,

1

such as:

 ownership of pore space (discussed in Chapter 5 of attached report);

 potential human health or ecological impacts if carbon dioxide leaks to the

surface or near-surface (discussed in Chapters 1, 4, and 6 of attached report);

 long-term liability (discussed in Chapters 7 and 8 of attached report); and,

 greenhouse gas regulatory accounting, which will be the enabling link to 

incentive structures that make GS economically viable (discussed in Chapters

8 and 9 of attached report).

8. Failure to resolve the above issues could make the commercial development of CCS

impossible.

9. The proposed rules for Class VI GS wells are more stringent than the other UIC well

classes (73 FR 43524-43525) yet they do not comprehensively manage issues of

concern for GS. With this limitation, the proposed rules run the risk of locking in a

regulatory framework that ultimately inhibits widespread commercial deployment of

CCS.

Overarching recommendations

10. The inability of the proposed rule to manage the issues listed above should be

remedied by either:

a. passage of new federal legislation to supplement the UIC program and amend 

the SDWA; or

b. passage of new freestanding federal legislation to regulate GS

comprehensively.

These options are detailed in Chapter 6 of the attached report.

 1 These limitations are acknowledged by the agency in the preamble to the rule. (73 FR 43,495)
3

11. To prevent creation of an overly inhibitive regulatory framework, the UIC program

should continue to permit wells injecting CO2 under existing well classes and/or the

proposed Class VI rules, for a limited and defined period. Concurrently, a

Commission or an Interagency Task Force (established either through legislation or

executive order of the President) should gather and synthesize results from pilot and 

early commercial-scale projects, providing recommendations to Congress on the

proper format to regulate widespread commercial CCS. Chapter 11 of the attached 

report details this two-stage approach.

12. Adoption of the Class VI rules should be accompanied by funding adequate to 

implement them. Regulation of GS through the UIC program cannot be effective

unless funding is provided commensurate to the goals of the Class VI program. The

EPA UIC budget, including grants to state programs, is chronically underfunded.

Annual federal appropriations to the UIC program have been approximately $11

million: less than half the funding level ($25 million per year) authorized in the

SDWA. Studies by the Ground Water Protection Council show that the Class V

program would need an additional $50 million annually to meet its objectives and that

the Class II program is under-funded by approximately $25 million annually. An 

under-resourced regulatory agency cannot ensure the safe and effective operation of

GS projects.

Issues that would requirement amendment of the SWDA or passage of new legislation

13. Need to balance multiple environmental interests: Protection of drinking water is an 

essential environmental goal, but must be balanced with avoidance of the dangerous

impacts of climate change. As mandated by the SDWA, the UIC Program rules have

been developed with the objective of preventing any migration of injected fluid or

other contaminants into USDWs. In practice, however, regulatory treatment of

injectate migration has been less clear-cut. For example the experience in Florida,

discussed in Chapter 6 of the attached report, suggests that it would be highly 

desirable to have arrangements in place ahead of time to allow balancing of

potentially conflicting national environmental interests. We recommend that the

SDWA be amended to allow balancing multiple environmental interests.

14. Ownership of Pore Space: Considerable ambiguity exists today in the U.S. as to the

current ownership of the deep pore space that would hold injected CO2, and how the

right to use deep pore space would be obtained for GS purposes. It appears that most

injectors of waste fluids into other well classes regulated by the UIC have not secured 

rights or permission to use the pore space from any surface or sub-surface property

owners. At least a few of those injection projects likely involve volumes of fluid as

large or larger than the volumes of CO2 that will be involved in commercial-scale

CCS projects. In order for CCS to remain an economic possibility, new legislation 

must allow the federal or state governments to intervene to manage or limit private

property rights for the use of pore space for GS. Otherwise, states or private property

owners could demand high rental rates that could block development of CCS.
4

15. Potential Health or Environmental Impacts other than to Groundwater: While we

believe that the risk of health or environmental impacts other than to groundwater is

very slight for sites that are well-characterized and well-operated, we understand that

this is a topic of concern to the public. The inability of the proposed UIC Class VI

rules to address these concerns carries the potential to undermine public acceptance of

CCS. Should such impacts occur under the proposed UIC Class VI rules, some other

regulator would need to intervene. It would be preferable, and more efficient, to have

site permitting conducted by a program with the authority to manage all potential

risks from CO2 injection comprehensively.

16. Long-term Liability: Widespread commercial deployment of CCS requires a clear

prior understanding of what entity will be responsible and financially liable for

assuring that injected CO2 remains safely underground after operations at the site

cease. Private sector entities often have relatively short time-horizons and lifetimes

in comparison with the period over which injected CO2 must remain sequestered.

Thus, we have serious doubts about the efficacy of holding operators responsible in 

perpetuity, as under the proposed UIC class VI rules. A number of alternative

strategies could be used to finance and manage long-term liability, as detailed in 

Chapters 7 and 8 of the attached report. We believe that settling the question of longterm liability, in a manner that gives confidence to both the public and project

financial backers, will require either amendment of the SDWA, or passage of new

legislation, to allow legal responsibility for closed GS sites to be transferred to a third 

party or government entity.

Specific comments on the proposed rule

17. Iterative Area of Review: We support the proposal to reevaluate iteratively the area of

review over the project life cycle and to allow phased corrective action (sec. 146.84).

18. Relationship between Class VI Wells and Class II Wells: Regulations for GS site

permitting should create a clear path by which CO2-flood enhanced oil recovery

(EOR) projects permitted as UIC Class II wells, can become commercial

sequestration projects under new regulations. The risk profile at a site operated for

EOR will change when the site transitions to GS as different stresses are placed on 

wells and geologic formations. The Class VI rules should provide more specific and 

comprehensive guidance on how an operator must demonstrate that a Class II site can

safely contain injected CO2 as a commercial sequestration project. The proposed 

Class VI rules lay the groundwork, by providing the Director with discretion to

“grandfather” only the construction requirements for existing Class I and Class II

wells seeking a permit for GS (provided he/she is able to make a determination that

these wells would not endanger USDWs) and requiring operators to meet all other

requirements of the proposed rule. However, additional conditions are needed, such 

as:

 Establishment of monitoring and reporting requirements for EOR sites that

wish to be eligible for crossover;
5

 Specification of the technical requirements for an operator to demonstrate

that a Class II well could be reclassified as a Class VI well; and

 Much of the data for EOR projects is currently proprietary. The rule

should address what types of data must be made public for EOR sites that

wish to be eligible for crossover.

Similar clarifications are needed for pilot and early-mover projects permitted as UIC

Class V wells which later might be converted to commercial sequestration projects.

19. Post-injection site care: We support the site-specific approach to post-injection site

care that EPA proposes in section 146.93.

20. Site closure: We support the general approach that EPA proposes to determine the

length of the post-injection site care period (a performance standard, anchored by a

suggested duration of several decades). However, we suggest three modifications: 1)

The rule should require that the post-injection site care and site-closure plan specify 

thresholds for demonstrating that the GS project no longer poses an endangerment to

USDWs; 2) The rule should provide mechanisms to coordinate information and

allocate responsibility if site conditions during the post-injection site care period are

altered by operations of another GS project in the basin; and, 3) The 50-year time

period should not become a prescriptive default. There is not yet enough experience

to set this as the suggested duration of the post-injection site care period. For now, a

performance standard alone is preferable and creates the right incentives to protect

USDWs. After experience has been gained from early projects, the rule could be

amended to include a suggested duration.

21. Performance standards: We support EPA’s general approach of establishing

performance standards for acceptable operation, but strongly caution that action

thresholds or performance standards established for the Class VI rule should not be

expressed as quantitative requirements for maximum leakage (or minimum retention)

from the injection zone. Current monitoring methods cannot quantify low-level

leakage rates or volume retained at reasonable cost or with needed precision, as

detailed in Chapter 4 of the attached report. Thus, other performance measures are

needed.

22. Primacy issues: Many geological formations suitable for GS span state boundaries,

making consistent regulation important. The proposed rule calls for "Director

discretion" over a number of important issues. This flexibility is necessary because

of geologic variability across the U.S., but should be balanced by inclusion of specific

thresholds for action, to provide consistency. In other words, because of the potential

for basin-scale, interstate interactions with GS, the primacy for Class VI wells should 

be more constrained than for other well classes.
6

23. Appropriate outreach techniques: The proposed rule’s 30-day public comment period

for GS wells should be extended to at least 60 days because of the complexity of the

issues. EPA should utilize modern media (electronic and digital communications,

including, but not limited to web-pages and e-mails) to inform local citizens about GS

site permitting.

24. Use of proprietary models: Use of proprietary models has the potential to exaggerate

information asymmetry among project operators, regulators and the public. If the

project operator uses proprietary software for modeling, then they should be required 

to provide all key modeling assumptions, run sensitivity analyses on important inputs,

or provide additional model runs of the data in a publicly available model acceptable

to EPA.

25. Perverse incentives: The stringency of the Class VI rules (relative to the other UIC

well classes) may create perverse incentives. For example, an operator could add 

hydrogen sulfide to the carbon dioxide stream and then seek a Class I permit with less

stringent area of review, monitoring, post-injection and closure requirements than a

Class VI permit. Thus, EPA should review the requirements and applicability of Class

I wells in conjunction with the proposed rulemaking for Class VI wells.

Conclusion

26. The CCS Regulatory Project shares EPA's commitment, and that of other participants

in the national discussion, to advancing the potential for safe and effective geological

sequestration of carbon dioxide. To that end, the agency's draft rules are, subject to

the specific concerns raised in our comments, a laudable effort to define a regulatory 

framework for assuring that carbon capture and sequestration proceed in a manner

that is calculated to protect the nation's water supply. But, in our judgment, the

objectives we share with EPA are best served by a regulatory scheme that takes into

account, and ultimately advances, the full range of environmental imperatives that

drive the development of CCS in the first place. With the impending advent of a new

administration and a new Congress, both of which are expected to be attentive to 

issues related to climate change, the potential for near-term legislative action is

relatively high. In these circumstances, EPA should consider using existing 

regulatory authority under the UIC program to license the first few CCS projects, but

wait to finalize rules for GS wells until they can be drafted under the authority of new

or amended legislation that enables more comprehensive regulation.
This document is not available in Regulations.gov since it 

contains copyrighted material that may not be reproduced 

without consent of the copyright holder. 

Contact the EPA Docket Center, Public Reading Room to view 

or receive a copy of this document. Requests for copies may be 

made as follows: 

In person/writing: 

Environmental Protection Agency, Docket Center 

1301 Constitution Ave NW, 2822T, Room 3334 

Washington, DC. 20004 

Telephone: 

202-566-1744 

Fax: 

202-566- 9744 

Email: 

docket-customerservice@epa.gov
Letter ID: 0233 

Commenter: M. Granger Morgan 

Organization: Carnegie Mellon University on behalf of the CCS Reg Project 

Letter ID: 0233 Comment ID: 21898 Letter Lines: 63 to 71 

Comment Code: 1420 1.2.1.1 Support the GS rulemaking 

Comment: Overarching issues and concerns 

6. We applaud EPA’s work toward developing regulations for GS. It is urgent that 

the U.S. moves forward with deployment of CCS technologies: EPA’s effort to 

write rules for GS wells incorporating sound scientific and technical knowledge 

contributes to creating a regulatory framework that ensures that GS will be done 

in a manner that is safe and environmentally sound. The speed with which EPA 

drafted these rules, and the inclusiveness of the rulewriting process, are well 

matched to the urgency and broad interest in the problem. 

Individual Response: EPA believes that the creation of a new injection well class (VI) under the 

existing UIC Program is necessary to enable the use of GS as a climate change mitigation 

technology in a manner that protects USDWs from endangerment. EPA agrees that the UIC 

Program, under the authority of the SDWA, provides a strong framework for regulating injection 

of CO2 for GS and adds that the GS regulation tailors the UIC requirements to address the 

unique issues associated with large-scale GS including large injection volumes, the relative 

buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurities in 

captured CO2, and its mobility within subsurface geologic formations. 

EPA agrees that input of and participation by a wide spectrum of stakeholders is a vital 

component of successful rulemaking. The Agency appreciates the degree of cooperation, 

participation, and active dialogue between the EPA and stakeholders and will continue to work 

with stakeholders and experts as it implements the GS rule. 

Letter ID: 0233 Comment ID: 21899 Letter Lines: 73 to 91 

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

ownership 

Comment Code: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 

Comment: 7. EPA’s laudable efforts notwithstanding, we believe the Safe Drinking Water 

Act (SDWA) does not provide adequate authority to comprehensively regulate GS. 

Because the statutory authority for the UIC Program derives from the SDWA, the 

proposed rule is unable to address key issues that must be resolved for 

commercial-scale GS,[FN1] such as: 

• ownership of pore space (discussed in Chapter 5 of attached report); 

1
• potential human health or ecological impacts if carbon dioxide leaks to the 

surface or near-surface (discussed in Chapters 1, 4, and 6 of attached report); 

• long-term liability (discussed in Chapters 7 and 8 of attached report); and, 

• greenhouse gas regulatory accounting, which will be the enabling link to 

incentive structures that make GS economically viable (discussed in Chapters 8 

and 9 of attached report). 

[FN1: These limitations are acknowledged by the agency in the preamble to the 

rule. (73 FR 43,495)] 

8. Failure to resolve the above issues could make the commercial development of 

CCS impossible. 

Individual 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; and the 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 is also aware that states are currently in various stages of developing statutory frameworks, 

regulations, technical guidance, and strategies for addressing CCS and GS. States can use 

multiple authorities beyond those afforded under the SDWA and UIC regulations, including laws 

and policies addressing surface access and land rights, unitization of fields, pore space 

ownership, mineral rights, worker safety and emergency preparedness, and maximization of state 

oil and gas resource exploitation. EPA plans to work closely with states and tribes as they 

develop Class VI primacy programs in this broader context. EPA adds that states may adopt 

more stringent standards for Class VI wells than the Federal requirements. 

The final rulemaking falls within EPA’s authority under the SDWA. EPA clarifies that the 

SDWA provides EPA with the authority to develop federal minimum requirements for 

underground injection, such as GS, that are directly related to protecting USDWs from 

endangerment. Thus EPA does not have authority under the SDWA to address other general 

issues related to CCS, such as capture and transportation. EPA clarifies that the GS rule does not 

address the status of CO2 as a pollutant or commodity. The UIC requirements regulate the 

injection of fluids. EPA adds that regulating carbon cap-and trade is outside of the UIC 

program's authority under SDWA. 

2
EPA recognizes that liability is an important issue to owners or operators but the Agency does 

not have authority under the SDWA to transfer long-term liability from owners or operators to 

the state or federal government. Therefore, liability remains with the owner or operator. 

Letter ID: 0233 Comment ID: 21900 Letter Lines: 93 to 97 

Comment Code: 1200 1.1 General comments about the rulemaking 

Comment: 9. The proposed rules for Class VI GS wells are more stringent than the other 

UIC well classes (73 FR 43524-43525) yet they do not comprehensively manage 

issues of concern for GS. With this limitation, the proposed rules run the risk 

of locking in a regulatory framework that ultimately inhibits widespread 

commercial deployment of CCS. 

Individual Response: EPA clarifies that the GS rule does not promote or encourage the use of 

GS; rather, it ensures consistency in permitting underground injection of CO2 at GS operations 

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

anticipation of the eventual use of GS to reduce CO2 emissions. EPA believes that the GS 

regulation will provide the regulatory certainty and oversight that operators have requested, and 

allow for the deployment of this key climate change mitigation technology that could be 

deployed to reduce CO2 emissions. Please see the remainder of EPA's responses to this comment 

for further details. 

Letter ID: 0233 Comment ID: 21901 Letter Lines: 99 to 108 

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

ownership 

Comment Code: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 

Comment: Overarching recommendations 

10. The inability of the proposed rule to manage the issues listed above should 

be remedied by either: 

a. passage of new federal legislation to supplement the UIC program and amend 

the SDWA; or 

b. passage of new freestanding federal legislation to regulate GS 

comprehensively. 

These options are detailed in Chapter 6 of the attached report [SEE PDF TO VIEW THE 

REPORT]. 

Individual Response: This comment is outside the scope of this rulemaking. As described 

above, EPA recognizes that a more comprehensive framework may be needed and that some 

stakeholders remain uncertain about the potential applicability of other federal environmental 

3
statutes, such as the Clean Air Act, to various aspects of GS. The Agency is currently evaluating 

the need for a more comprehensive regulatory framework for this emerging technology. 

Letter ID: 0233 Comment ID: 21902 Letter Lines: 110 to 118 

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: 11. To prevent creation of an overly inhibitive regulatory framework, the UIC 

program should continue to permit wells injecting CO2 under existing well 

classes and/or the proposed Class VI rules, for a limited and defined period. 

Concurrently, a Commission or an Interagency Task Force (established either 

through legislation or executive order of the President) should gather and 

synthesize results from pilot and early commercial-scale projects, providing 

recommendations to Congress on the proper format to regulate widespread 

commercial CCS. Chapter 11 of the attached report details this two-stage 

approach [SEE PDF TO VIEW THE REPORT]. 

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. 

The Agency is using an adaptive approach to regulate GS injection. EPA will collect and review 

project data on early GS projects, including pilot projects, 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 does not plan to establish a 

task force for this purpose, however. 

Letter ID: 0233 Comment ID: 21903 Letter Lines: 120 to 130 

Comment Code: 5600 2.11 Comments related to UIC Program primacy for Class VI wells 

Comment: 12. Adoption of the Class VI rules should be accompanied by funding adequate to 

implement them. Regulation of GS through the UIC program cannot be effective 

unless funding is provided commensurate to the goals of the Class VI program. 

The EPA UIC budget, including grants to state programs, is chronically 

underfunded. Annual federal appropriations to the UIC program have been 

approximately $11 million: less than half the funding level ($25 million per 

year) authorized in the SDWA. Studies by the Ground Water Protection Council 

show that the Class V program would need an additional $50 million annually to 

4
meet its objectives and that the Class II program is under-funded by 

approximately $25 million annually. An under-resourced regulatory agency cannot 

ensure the safe and effective operation of GS projects. 

Individual Response: EPA acknowledges that there may be technical and administrative 

challenges including resource concerns, and will work closely with the states to assist them in 

resolving funding issues or acquiring the resources, personnel, and training needed to address the 

unique technical challenges associated with GS. 

EPA will also incorporate Class VI wells into the UIC Program's grant allocation process. The 

States/Tribes/Territories must also demonstrate that they have adequate resources to implement 

the program through matching resources against those allocated by the UIC Program's grant 

allocation formula. Currently, primacy programs are required to meet a minimum of 25 percent 

matching requirement. 

Letter ID: 0233 Comment ID: 21904 Letter Lines: 132 to 145 

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

ownership 

Comment Code: 1400 1.2 Comments on EPA's Authority to Regulate Injection of CO2 

Comment: Issues that would requirement amendment of the SWDA or passage of new 

legislation 

13. Need to balance multiple environmental interests: Protection of drinking 

water is an essential environmental goal, but must be balanced with avoidance of 

the dangerous impacts of climate change. As mandated by the SDWA, the UIC 

Program rules have been developed with the objective of preventing any migration 

of injected fluid or other contaminants into USDWs. In practice, however, 

regulatory treatment of injectate migration has been less clear-cut. For example 

the experience in Florida, discussed in Chapter 6 of the attached report [SEE PDF TO VIEW 

THE REPORT], 

suggests that it would be highly desirable to have arrangements in place ahead 

of time to allow balancing of potentially conflicting national environmental 

interests. We recommend that the SDWA be amended to allow balancing multiple 

environmental interests. 

Individual Response: This comment is outside the scope of the rulemaking. As described 

above, EPA recognizes that a more comprehensive framework may be needed and that some 

stakeholders remain uncertain about the potential applicability of other federal environmental 

statutes, such as the Clean Air Act, to various aspects of GS. The Agency is currently evaluating 

the need for a more comprehensive regulatory framework for this emerging technology. 

5
Letter ID: 0233 Comment ID: 21905 Letter Lines: 147 to 158 

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

ownership 

Comment: 14. Ownership of Pore Space: Considerable ambiguity exists today in the U.S. as 

to the current ownership of the deep pore space that would hold injected CO2, 

and how the right to use deep pore space would be obtained for GS purposes. It 

appears that most injectors of waste fluids into other well classes regulated by 

the UIC have not secured rights or permission to use the pore space from any 

surface or sub-surface property owners. At least a few of those injection 

projects likely involve volumes of fluid as large or larger than the volumes of 

CO2 that will be involved in commercial-scale CCS projects. In order for CCS to 

remain an economic possibility, new legislation must allow the federal or state 

governments to intervene to manage or limit private property rights for the use 

of pore space for GS. Otherwise, states or private property owners could demand 

high rental rates that could block development of CCS. 

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, which 

focuses on ensuring consistency in permitting underground injection of CO2 at GS operations 

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

anticipation of the eventual use of GS to reduce CO2 emissions. EPA clarifies that these issues 

are under the purview of states and any of these issues, as they relate to GS, will need to be 

addressed though state regulations. 

Letter ID: 0233 Comment ID: 21906 Letter Lines: 160 to 169 

Comment Code: 1500 1.2.2.2.4 Some other agency should regulate GS 

Comment Code: 1650 1.3.5 Human health impacts 

Comment Code: 1660 1.3.6 Ecosystem impacts (soil, air, surface water) 

Comment: 15. Potential Health or Environmental Impacts other than to Groundwater: While 

we believe that the risk of health or environmental impacts other than to 

groundwater is very slight for sites that are well-characterized and welloperated, we understand that this is a topic of concern to the public. The 

inability of the proposed UIC Class VI rules to address these concerns carries 

the potential to undermine public acceptance of CCS. Should such impacts occur 

under the proposed UIC Class VI rules, some other regulator would need to 

intervene. It would be preferable, and more efficient, to have site permitting 

conducted by a program with the authority to manage all potential risks from CO2 

injection comprehensively. 

Individual Response: EPA agrees that properly managed GS projects present lower risk. EPA 

believes that the GS requirements, which are based on the long-standing UIC regulatory 

framework and tailored to meet the unique nature of CO2 injection for GS, appropriately address 

6
endangerment risks to USDWs. The GS rule contains minimum technical criteria for the 

permitting, geologic site characterization, AoR and corrective action, well construction, 

operation, mechanical integrity testing, monitoring, financial responsibility, injection well 

plugging, post-injection site care, and site closure of GS wells, which will ensure that USDWs 

are protected from endangerment. 

EPA acknowledges that the issue of GS falls within the broader context of CCS, but clarifies that 

the scope of the GS regulation is limited to injection of CO2, and that all requirements in the GS 

rule are designed for the purpose of protecting USDWs from endangerment. The SDWA does 

not provide the UIC Program with the authority to develop regulations for all areas related to GS, 

such as releases to the atmosphere. 

EPA believes that the creation of a new injection well class (VI) under the existing UIC Program 

is necessary to enable deployment of GS as a climate change mitigation technology in a manner 

that protects USDWs from endangerment. EPA agrees that the UIC Program, under the authority 

of the SDWA, provides a strong framework for regulating injection of CO2 for GS and adds that 

the GS regulation tailors the UIC requirements to address the unique issues associated with 

large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in 

the presence of water, the potential presence of impurities in captured CO2, and its mobility 

within subsurface geologic formations. 

To the comment that the geologic siting requirements could create a negative public perception, 

EPA believes that a demonstration to the public, through the promulgation of the GS rule, that 

extensive data have been collected and evaluated will likely improve confidence in the project 

and help address public questions and concerns. 

Regarding the suggestion to develop an integrated permitting process that addresses the entire 

CCS process, EPA clarifies that the UIC Program's authority is limited to ensuring that GS 

projects protect USDWs from endangerment. Oversight of the capture and transport of CO2 is 

outside of SDWA authority. 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; and the 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. 

Letter ID: 0233 Comment ID: 21907 Letter Lines: 171 to 184 

7
Comment Code: 5460 2.9.2 Comments on transfer of liability for long-term care 

Comment: 16. Long-term Liability: Widespread commercial deployment of CCS requires a 

clear prior understanding of what entity will be responsible and financially 

liable for assuring that injected CO2 remains safely underground after 

operations at the site cease. Private sector entities often have relatively 

short time-horizons and lifetimes in comparison with the period over which 

injected CO2 must remain sequestered. Thus, we have serious doubts about the 

efficacy of holding operators responsible in perpetuity, as under the proposed 

UIC class VI rules. A number of alternative strategies could be used to finance 

and manage long-term liability, as detailed in Chapters 7 and 8 of the attached 

report [SEE PDF TO VIEW THE REPORT]. We believe that settling the question of long-term 

liability, in a 

manner that gives confidence to both the public and project financial backers, 

will require either amendment of the SDWA, or passage of new legislation, to 

allow legal responsibility for closed GS sites to be transferred to a third 

party or government entity. 

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. 

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 

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

EPA's final approach. 

8
Letter ID: 0233 Comment ID: 21908 Letter Lines: 186 to 190 

Comment Code: 3500 2.2.3 Area of Review Reevaluation (seeking comment) 

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

Comment: Specific comments on the proposed rule 

17. Iterative Area of Review: We support the proposal to reevaluate iteratively 

the area of review over the project life cycle and to allow phased corrective 

action (sec. 146.84). 

Individual Response: EPA acknowledges the commenter’s support of AoR reevaluations and 

phased corrective action. EPA believes that the AoR reevaluation process at §146.84(e) provides 

additional opportunities to verify that the models have accurately predicted movement of the 

CO2 plume and to make any needed adjustments to corrective action or monitoring at the site, 

and has retained this approach in the final rule. 

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 retained it at §146.84(b)(2)(iv) in the final GS 

regulation. 

Letter ID: 0233 Comment ID: 21909 Letter Lines: 192 to 219 

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: 18. Relationship between Class VI Wells and Class II Wells: Regulations for GS 

site permitting should create a clear path by which CO2-flood enhanced oil 

recovery (EOR) projects permitted as UIC Class II wells, can become commercial 

sequestration projects under new regulations. The risk profile at a site 

operated for EOR will change when the site transitions to GS as different 

stresses are placed on wells and geologic formations. The Class VI rules should 

provide more specific and comprehensive guidance on how an operator must 

demonstrate that a Class II site can safely contain injected CO2 as a commercial 

sequestration project. The proposed Class VI rules lay the groundwork, by 

providing the Director with discretion to "grandfather" only the construction 

requirements for existing Class I and Class II wells seeking a permit for GS 

(provided he/she is able to make a determination that these wells would not 

endanger USDWs) and requiring operators to meet all other requirements of the 

proposed rule. However, additional conditions are needed, such as: 

9
• Establishment of monitoring and reporting requirements for EOR sites that wish 

to be eligible for crossover; 

• Specification of the technical requirements for an operator to demonstrate 

that a Class II well could be reclassified as a Class VI well; and 

• Much of the data for EOR projects is currently proprietary. The rule should 

address what types of data must be made public for EOR sites that wish to be 

eligible for crossover. 

Similar clarifications are needed for pilot and early-mover projects permitted 

as UIC Class V wells which later might be converted to commercial sequestration 

projects. 

Individual Response: 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. 

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

EPA agrees that 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 clarifies that monitoring and reporting requirements for all GS projects are described in 

§146.90. This section requires owners or operators to develop a site-specific monitoring and 

testing plan and submit it along with the permit application. 

Letter ID: 0233 Comment ID: 21910 Letter Lines: 221 to 222 

10
Comment Code: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93) 

Comment: 19. Post-injection site care: We support the site-specific approach to postinjection site care that EPA proposes in section 146.93. 

Individual Response: EPA acknowledges the commenter’s support; the final rule retains this 

provision. 

Letter ID: 0233 Comment ID: 21911 Letter Lines: 224 to 237 

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

Comment Code: 5280 2.8.2.4 USDW non-endangerment demonstrations 

Comment: 20. Site closure: We support the general approach that EPA proposes to determine 

the length of the post-injection site care period (a performance standard, 

anchored by a suggested duration of several decades). However, we suggest three 

modifications: 1) The rule should require that the post-injection site care and 

site-closure plan specify thresholds for demonstrating that the GS project no 

longer poses an endangerment to USDWs; 2) The rule should provide mechanisms to 

coordinate information and allocate responsibility if site conditions during the 

post-injection site care period are altered by operations of another GS project 

in the basin; and, 3) The 50-year time period should not become a prescriptive 

default. There is not yet enough experience to set this as the suggested 

duration of the post-injection site care period. For now, a performance standard 

alone is preferable and creates the right incentives to protect USDWs. After 

experience has been gained from early projects, the rule could be amended to 

include a suggested duration. 

Individual Response: EPA agrees that the rule should not specify the criteria for setting the 

monitoring timeframe. Instead, EPA believes that such determinations are site-specific and 

should be described in a project-specific post-injection site care and site closure plan. However, 

EPA disagrees that the plan should specify thresholds for demonstrating that the GS project no 

longer poses a risk of endangerment to USDWs, but agrees that this demonstration should be an 

important consideration. EPA is developing guidances with recommended approaches for 

developing and implementing post-injection site care and site closure plans and guidance that 

describes recommended approaches for how an owner or operator could plug injection and 

monitoring wells, perform post-injection monitoring, demonstrate non endangerment, and 

perform site closure activities. The guidances will be available at 

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

EPA agrees with commenters that there will be circumstances where it can be demonstrated in 

less than 50 years that the plume and pressure front no longer pose a risk of endangerment to 

USDWs. For this reason, the final GS regulation includes a provision that the Director may, at 

his or her discretion, shorten the post-injection site care timeframe if the owner or operator can 

demonstrate that the GS project does not pose an endangerment to USDWs, as specified in 

§146.93(b)(2). Such a demonstration will be site-specific, and based on pressure monitoring and 

11
USDW impacts. EPA believes however, that to ensure USDW protection from endangerment, a 

default timeframe for post-injection site care is necessary. A 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. 

Letter ID: 0233 Comment ID: 21912 Letter Lines: 239 to 246 

Comment Code: 4000 2.4 Proposed Injection Well Operating Requirements (40 CFR 146.88) 

Comment: 21. Performance standards: We support EPA’s general approach of establishing 

performance standards for acceptable operation, but strongly caution that action 

thresholds or performance standards established for the Class VI rule should not 

be expressed as quantitative requirements for maximum leakage (or minimum 

retention) from the injection zone. Current monitoring methods cannot quantify 

low-level leakage rates or volume retained at reasonable cost or with needed 

precision, as detailed in Chapter 4 of the attached report [SEE PDF TO VIEW THE REPORT]. 

Thus, other 

performance measures are needed. 

Individual Response: EPA clarifies that the GS rule does not set specific quantitative 

requirements for maximum leakage (or minimum retention) of CO2 from the injection zone. 

Rather, the intent of the rule is to ensure that injection wells are permitted, sited, constructed, 

operated, monitored, and plugged in a manner that does not endanger USDWs. The rule affords 

the Director discretion and flexibility to set permit conditions to ensure that USDWs are 

protected from the impacts of GS projects. 

Letter ID: 0233 Comment ID: 21913 Letter Lines: 248 to 255 

Comment Code: 5600 2.11 Comments related to UIC Program primacy for Class VI wells 

Comment: 22. Primacy issues: Many geological formations suitable for GS span state 

boundaries, making consistent regulation important. The proposed rule calls for 

"Director discretion" over a number of important issues. This flexibility is 

necessary because of geologic variability across the U.S., but should be 

balanced by inclusion of specific thresholds for action, to provide consistency. 

In other words, because of the potential for basin-scale, interstate 

interactions with GS, the primacy for Class VI wells should be more constrained 

than for other well classes. 

Individual Response: EPA agrees with commenters on the importance of allowing Director's 

discretion given the variety of geologic settings in which GS will be applied. EPA recognizes 

12
that State, Tribal, Territorial, 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 standards to ensure national consistency. 

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 on 

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. 

Letter ID: 0233 Comment ID: 21914 Letter Lines: 256 to 259 

Comment Code: 5520 2.10.1 Appropriateness of existing public participation requirements 

(Part 25 and Part 124) for GS (seeking comment) 

Comment: 

23. Appropriate outreach techniques: The proposed rule’s 30-day public comment 

period for GS wells should be extended to at least 60 days because of the 

complexity of the issues. EPA should utilize modern media (electronic and 

Individual Response: EPA disagrees that a 60-day comment period should be required for all 

GS projects. EPA believes that the existing public comment period requirements at 40 CFR 

124.10, which requires a minimum 30-day comment period for draft permits, are appropriate for 

GS projects. The Agency does not believe it is appropriate to impose longer time frames if they 

are unnecessary, but supports the Directors' discretion and authority under 40 CFR 124.10 to 

extend the public comment period if he or she determines that such an extension is warranted. 

Circumstances that may affect a Director's determination may include the level of public interest 

in a GS project, specific permit details, or project-specific considerations. 

Letter ID: 0233 Comment ID: 21915 Letter Lines: 259 to 261 

Comment Code: 5540 2.10.2 Need for additional public participation requirements/ use of new 

information technology (seeking comment) 

Comment: complexity of the issues. EPA should utilize modern media (electronic and 

digital communications, including, but not limited to web-pages and e-mails) to 

inform local citizens about GS site permitting. 

13
Individual Response: EPA agrees with commenters that the use of new forms of information 

technology can improve public participation and understanding of GS projects and the associated 

injection technologies involved. EPA does not require the use of any new information 

technologies to inform the public, but encourages GS project operators and permitting authorities 

to use the Internet as well as both new and established tools to explain and post information on 

the latest developments. This information may include schedules for hearings, briefings, and 

other opportunities for involvement. EPA plans to conduct outreach on the GS rule, and provides 

GS-related information on its website at 

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm. EPA currently uses social 

networking applications for important information (e.g., Facebook and Twitter), and will 

encourage GS operators and permitting authorities to use similar technologies to keep the public 

informed of GS projects. 

Letter ID: 0233 Comment ID: 21916 Letter Lines: 263 to 268 

Comment Code: 3350 2.2.1.5 Use of proprietary models for GS sites (seeking comment) 

Comment: 24. Use of proprietary models: Use of proprietary models has the potential to 

exaggerate information asymmetry among project operators, regulators and the 

public. If the project operator uses proprietary software for modeling, then 

they should be required to provide all key modeling assumptions, run sensitivity 

analyses on important inputs, or provide additional model runs of the data in a 

publicly available model acceptable to EPA. 

Individual Response: EPA shares the commenter’s concern about the need to evaluate the 

inputs and assumptions used. EPA will allow the use of proprietary models in meeting the 

requirements for the GS regulation, as long as GS well operators using a proprietary model 

clearly disclose, to the Director's satisfaction, the code assumptions, relevant equations, and 

scientific basis. EPA also agrees that sensitivity analyses should be presented by the owner or 

operator and evaluated by the Director. If during the permit review, the Director determines that 

modeling results are too wide-ranging, further information will be required of the owner or 

operator. EPA adds that its Confidential Business Information requirements at 40 CFR 144.5 will 

apply to the use of proprietary models. 

The Agency plans, every six years, to collect and review data on GS projects to determine 

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

being collected, and to determine if modifications to the requirements are appropriate or 

necessary. 

Letter ID: 0233 Comment ID: 21917 Letter Lines: 270 to 276 

Comment Code: 1210 1.1.1 Comments about the proposed rule 

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

14
Comment: 25. Perverse incentives: The stringency of the Class VI rules (relative to the 

other UIC well classes) may create perverse incentives. For example, an operator 

could add hydrogen sulfide to the carbon dioxide stream and then seek a Class I 

permit with less stringent area of review, monitoring, post-injection and 

closure requirements than a Class VI permit. Thus, EPA should review the 

requirements and applicability of Class I wells in conjunction with the proposed 

rulemaking for Class VI wells. 

Individual Response: EPA disagrees with this comment and does not anticipate this type of 

scenario will take place because under the final GS rule, owners or operators must determine 

whether the CO2 stream is hazardous under EPA’s RCRA regulations; If so, any injection of the 

hazardous CO2 stream may only occur in a Class I hazardous waste injection well under 40 CFR 

Part 146 Subpart G. For Class I hazardous wells, owners or operators are required under 40 CFR 

286.6 to demonstrate, to a reasonable degree of certainty, that there will be no migration of 

hazardous constituents from the disposal unit or injection zone for as long as the wastes remain 

hazardous or for 10,000 years via a fluid flow no migration petition. EPA anticipates that this 

may be very difficult to demonstrate for long-term storage of CO2 at anticipated volumes. 

Conversely, Class VI wells cannot be used for the co-injection of RCRA hazardous wastes (i.e., 

hazardous wastes that are injected along with the CO2 stream). 

EPA received many comments related to RCRA applicability to GS sites and 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. 

EPA adds that revising the requirements for other classes of wells is outside the scope of the GS 

rulemaking. 

Letter ID: 0233 Comment ID: 21918 Letter Lines: 278 to 295 

Comment Code: 1200 1.1 General comments about the rulemaking 

Comment: Conclusion 

26. The CCS Regulatory Project shares EPA's commitment, and that of other 

participants in the national discussion, to advancing the potential for safe and 

effective geological sequestration of carbon dioxide. To that end, the agency's 

draft rules are, subject to the specific concerns raised in our comments, a 

laudable effort to define a regulatory framework for assuring that carbon 

capture and sequestration proceed in a manner that is calculated to protect the 

nation's water supply. But, in our judgment, the objectives we share with EPA 

are best served by a regulatory scheme that takes into account, and ultimately 

15
16

advances, the full range of environmental imperatives that drive the development 

of CCS in the first place. With the impending advent of a new administration and 

a new Congress, both of which are expected to be attentive to issues related to 

climate change, the potential for near-term legislative action is relatively 

high. In these circumstances, EPA should consider using existing regulatory 

authority under the UIC program to license the first few CCS projects, but wait 

to finalize rules for GS wells until they can be drafted under the authority of 

new or amended legislation that enables more comprehensive regulation. 

Individual Response: The final rule is based on the most recent GS-related data, information, 

and scientific research available. EPA believes that sufficient data have been collected to inform 

the final GS rule. Nevertheless, EPA anticipates that future experimental and full-scale projects 

will continue to inform the technology, and is therefore using an adaptive rulemaking approach. 

EPA plans, every six years, to collect and review data on GS projects to 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.