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.
December 23, 2008

Water Docket

Environmental Protection Agency

Mailcode: 2822T

1200 Pennsylvania Ave., NW

Washington, DC 20460

Re: Association of State Drinking Water Administrators Comments on the Federal Requirements 

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

Sequestration (GS) Wells; Proposed Rule (Docket ID No. EPA-HQ-OW-2008-0390)

To Whom it May Concern:

On behalf of the state drinking water programs for the 50 states, the territories, the District of 

Columbia, and the Navajo Nation, the Association of State Drinking Water Administrators 

(ASDWA) would like to thank the Agency for the opportunity to comment on the Proposed 

Carbon Sequestration Rule as published in the Federal Register on July 25, 2008 (40 CFR Parts 

144 and 146). Our overall comments, as well as more specific points are provided below.

Overall Comments

ASDWA and its members appreciate EPA’s efforts to develop this rule under very limited time 

constraints and agree with EPA’s plan to create a new class of wells for carbon dioxide geologic 

sequestration sites. States believe that all appropriate steps need to be taken to ensure the 

effectiveness of Carbon Capture and Sequestration as a tool to mitigate greenhouse gas 

emissions, as well as avoid potential unintended consequences that could have a negative impact

on Underground Sources of Drinking Water (USDW). Additional research and data are needed 

to ensure that this rule is fully protective of all potential drinking water sources.

Specific Comments 

Geologic Siting Requirements and Area of Review (AOR)

· Additional Research and Data Needed: More research and data are needed, than are 

typically available now, to make scientific determinations as well as implement proven 

methods to ensure the integrity of the proposed geologic sites, without displacement of 
2

existing USDW. Such research and data will be particularly important with regard to

characterizing the thickness of the confining zone and permeability.

· Potential USDW Above 10,000 TDS: Since states and water utilities in many areas of the 

U.S. are currently addressing drought and water rights and availability issues, the proposed 

rule should provide for states to include protections for well sites with potentially viable 

sources of drinking water, such as saline aquifers and aquifers above 10,000 (mg/L) total 

dissolved solids (TDS) level that might serve as a viable drinking water source. ASDWA 

recommends that states be allowed regulatory flexibility to consider these aquifers as 

potential drinking water sources. Please note that there is some variance among states with 

regard to this issue. While some states would like Congress to consider changing the current 

Safe Drinking Water Act (SDWA) language to preclude these aquifers as potential 

sequestration sites, other states are actively looking for additional sequestration sites and 

would prefer that the proposed regulation and the current Safe Drinking Water Act (SDWA) 

language keep the current 10,000 TDS (mg/L) definition for a USDW. Thus, we recommend 

state-specific flexibility on this matter.

· Research on Fluid Movement: EPA should promote and support research and data 

collection to determine the risk associated with geologic sequestration of carbon dioxide and

to demonstrate that there is no fluid movement into a USDW. Some state laws regarding 

aquifer storage and recovery do not allow for any displacement of water.

· Drill Holes and Abandoned Wells: EPA should consider options to ensure that mineral 

exploration drill holes and abandoned wells are accounted for on the AOR maps. States have 

serious concerns about the ability to account for all of these potential holes and open shear 

zones or faults that may allow migration from the injection zone to the fresh water aquifers, 

as well as leakage out of the geo-sequestration site and back into the atmosphere. The AOR 

should also be periodically reevaluated, particularly as improved predictive models and new 

data become available.

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

· Guidelines Needed: It would be helpful if additional guidelines were included in the rule to 

provide state regulatory authorities with the ability to determine requirements for monitoring, 

corrective action, record keeping, and liability of carbon sequestration injection well sites. 

Guidelines are needed to help states consider baseline geochemical analysis and monitoring

data, as well as corrective action plans, in the event that a USDW becomes affected by an 

injection well site. Guidelines are also needed to ensure that the long-term financial 

responsibility of owners/operators of injection wells adequately cover the potential costs of 

site closure and stewardship. While the rule should provide some minimum requirements for 

record keeping and the frequency of reporting, the rule should also be flexible enough to

allow states to address site-specific conditions in determining these requirements. Common 

assumptions will need to be tested under the unique conditions of individual sites in order to 

avoid unintended consequences.
3

State Standards, Regulations, Funding, and Primacy Requirements

· State Flexibility Needed: The flexible regulatory approach that is built into the proposed 

rule appears to adequately provide for state implementation efforts to address site specific 

circumstances and assure that the rule is implemented toward the highest degree of protection 

for USDWs. However, the rule should also allow for state flexibility with regard to existing 

state standards and regulations, if they are more stringent (i.e., regarding well construction 

requirements) than the Federal rule.

· State Resources Needed: The financial and resource burden on EPA and state primacy

agencies to assess the geologic sequestration permit submissions, evaluate the technical 

models, and make permitting determinations will be greatly increased by this rule. Financial 

resource considerations should accompany eventual promulgation of the rule in order to 

ensure adequate state funding for these various tasks. 

· State Primacy Considerations: EPA should investigate options for state primacy

considerations under SDWA 1425 to regulate the new class VI wells for carbon sequestration

independently of other well classes. As the proposed rule is currently written, it precludes 

states that only have primacy on Class II wells.

Thank you for considering these various comments. Please let me know if we can provide any 

further information related to these comments. 

Sincerely,

James D. Taft

Executive Director
Letter ID: 0172 

Commenter: James Taft 

Organization: Association of State Drinking Water Administrators (ASDWA) 

Letter ID: 0172 Comment ID: 23449 Letter Lines: 38 to 48 

Comment Code: 1330 1.1.3.1 Support use of GS in general 

Comment Code: 1420 1.2.1.1 Support the GS rulemaking 

Comment Code: 2020 1.5.1 Support Class VI designation 

Comment: Overall Comments 

ASDWA and its members appreciate EPA’s efforts to develop this rule under very 

limited time constraints and agree with EPA’s plan to create a new class of 

wells for carbon dioxide geologic sequestration sites. States believe that all 

appropriate steps need to be taken to ensure the effectiveness of Carbon Capture 

and Sequestration as a tool to mitigate greenhouse gas emissions, as well as 

avoid potential unintended consequences that could have a negative impact on 

Underground Sources of Drinking Water (USDW). Additional research and data are 

needed to ensure that this rule is fully protective of all potential drinking 

water sources. 

Individual Response: EPA acknowledges the comment and agrees that tailored requirements for 

Class VI wells are necessary to address the unique nature of injecting large volumes of CO2 and 

to ensure that USDWs are protected from endangerment. The Class VI requirements are 

appropriate because of the unique nature and risks of CO2 injection for long-term storage (e.g., 

large injection volumes, long project duration, and reservoir pressure conditions). 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 agrees that continued research in all GS associated fields will be integral to development of 

GS technology. EPA is aware of research by other federal agencies, industry, international 

parties, and academia related to GS, including projects that address many of the topics suggested 

by commenters. EPA published a Notice of Data Availability (NODA) and Request for 

Comment on August 31, 2009 (74 FR 44802), in which the Agency described the results of 

research at three DOE partnership sites (in Escatawpa, Mississippi; the Aneth Field in Paradox 

Basin, southeast Utah; and the Pump Canyon Site, New Mexico). In the NODA and Request for 

Comment, EPA also described two studies by the Lawrence Berkeley National Laboratory on the 

potential effects of CO2 injection on ground water and surrounding formations to determine the 

potential for impacts on USDWs and human health in the event that a GS project is not properly 

sited, operated, or managed. 

To protect USDWs from endangerment and meet the potentially fast pace of GS deployment, 

1
EPA is using an adaptive approach to regulating CO2 injection for GS. The Agency plans to, 

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

amount and types of information and appropriate documentation are being collected, and to 

determine if modifications to the requirements are appropriate or necessary. An adaptive 

approach will allow regulatory development to proceed in time to meet the current and future 

demands for Class VI permits, while EPA continues to gather data from pilot projects and other 

research as it becomes available. 

Letter ID: 0172 Comment ID: 23450 Letter Lines: 50 to 60 

Comment Code: 1510 1.2.2.3 Need for additional study 

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

Comment: Specific Comments 

Geologic Siting Requirements and Area of Review (AOR) 

Additional Research and Data Needed: 

More research and data are needed, than are typically available now, to make 

scientific determinations as well as implement proven methods to ensure the 

integrity of the proposed geologic sites, without displacement of existing USDW. 

Such research and data will be particularly important with regard to 

characterizing the thickness of the confining zone and permeability. 

Individual Response: EPA agrees that continued research will be integral to development of GS 

technology, but disagrees that the Agency is unable to ensure the integrity of the proposed 

geologic sites. 

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

GS technology. EPA is aware of research by other federal agencies, industry, international 

parties, and academia related to GS, including projects that address many of the topics suggested 

by commenters. EPA published a Notice of Data Availability (NODA) and Request for 

Comment on August 31, 2009 (74 FR 44802), in which the Agency described the results of 

research at three DOE partnership sites (in Escatawpa, Mississippi; the Aneth Field in Paradox 

Basin, southeast Utah; and the Pump Canyon Site, New Mexico). In the NODA and Request for 

Comment, EPA also described two studies by the Lawrence Berkeley National Laboratory on the 

potential effects of CO2 injection on ground water and surrounding formations to determine the 

potential for impacts on USDWs and human health in the event that a GS project is not properly 

sited, operated, or managed. 

To protect USDWs from endangerment and meet the potentially fast pace of GS deployment, 

EPA is using an adaptive approach to regulating CO2 injection for GS. The Agency plans to 

collect and review data every six years on GS projects to determine whether the appropriate 

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

modifications to the requirements are necessary. An adaptive approach will allow regulatory 

2
development to proceed in time to meet the current and future demands for Class VI permits, 

while EPA continues to gather data from pilot projects and other research as it becomes 

available. 

Letter ID: 0172 Comment ID: 23451 Letter Lines: 62 to 78 

Comment Code: 1220 1.1.1.1 Terminology and definitions 

Comment Code: 4400 2.4.4.3 Allowing injection above or between USDWs (seeking comment) 

Comment: Potential USDW Above 10,000 TDS: 

Since states and water utilities in many areas of the U.S. are currently 

addressing drought and water rights and availability issues, the proposed rule 

should provide for states to include protections for well sites with potentially 

viable sources of drinking water, such as saline aquifers and aquifers above 

10,000 (mg/L) total dissolved solids (TDS) level that might serve as a viable 

drinking water source. ASDWA recommends that states be allowed regulatory 

flexibility to consider these aquifers as potential drinking water sources. 

Please note that there is some variance among states with regard to this issue. 

While some states would like Congress to consider changing the current Safe 

Drinking Water Act (SDWA) language to preclude these aquifers as potential 

sequestration sites, other states are actively looking for additional 

sequestration sites and would prefer that the proposed regulation and the 

current Safe Drinking Water Act (SDWA) language keep the current 10,000 TDS 

(mg/L) definition for a USDW. Thus, we recommend state-specific flexibility on 

this matter. 

Individual Response: EPA is not changing the USDW definition; changing the definition of a 

USDW is outside the scope of the GS rulemaking. The GS rule focuses on ensuring protection of 

USDWs, as required under the SDWA, by establishing regulations to ensure the safe injection of 

CO2 for long-term storage. 

EPA recognizes that there is increasing demand for water resources and that technology 

improvements may make high TDS aquifers viable drinking water sources. EPA believes these 

potential resources should be considered when injection depth waivers are sought. Therefore, the 

final GS rule at §146.95(b) requires the Director to consider these issues in determining whether 

an injection depth waiver is appropriate. Specifically, the Director must consider whether 

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

water resources; planned needs, potential and/or future use of USDWs and non-USDWs in the 

area; and a plan for securing alternative resources or treating USDW formation waters in the 

event of contamination related to the Class VI injection activity. 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. 

3
Letter ID: 0172 Comment ID: 23452 Letter Lines: 80 to 85 

Comment Code: 1810 1.4.1 Research on identifying risks to USDWs 

Comment: Research on Fluid Movement: 

EPA should promote and support research and data collection to determine the 

risk associated with geologic sequestration of carbon dioxide and to demonstrate 

that there is no fluid movement into a USDW. Some state laws regarding aquifer 

storage and recovery do not allow for any displacement of water. 

Individual Response: EPA is working with DOE, national laboratories (such as Lawrence 

Berkeley National Laboratories), USGS, and internal Agency Offices (e.g., Office of Research 

and Development) on research on various aspects of GS, including potential risks to USDWs. 

EPA published a NODA and Request for Comment on August 31, 2009 (74 FR 44802), in which 

the Agency described two studies by the LBNL on the potential effects of CO2 injection on 

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

managed. These studies are in the rulemaking docket and on LBNL's website at 

http://esd.lbl.gov/GCS/projects/CO2/index_CO2.html. 

EPA is also funding a project at LBNL to integrate experimental and modeling efforts to 

evaluate the potential consequences of CO2 leaks from GS operations into ground water 

resources. 

EPA is tracking other recent research on GS and USDW protection including the following 

studies (which are available in the docket for the rulemaking): 

• Smyth et al. (2008) reviewed modeling and laboratory experiments and field results from 

groundwater studies conducted at SACROC, an ER site in west Texas where tens of millions of 

tons of CO2 have been injected for over 30 years. 

• Zheng et al. (2008) used more than 38,000 groundwater quality analyses from aquifers 

throughout the US to perform reactive transport modeling of groundwater quality after the 

intrusion of CO2. The model simulations indicate that aquifers containing more carbonate and 

clay minerals are less vulnerable to CO2 intrusion, and that, while under certain conditions CO2 

can potentially mobilize metals present in the aquifer, mobilized amounts of the metals are 

always below health-based limits. 

• Kharaka et al. (2009) conducted CO2 injection field tests in Montana and reported that 

shallowly injected CO2 can affect the chemistry of shallow groundwater by decreasing pH and 

mobilizing rock and soil ions. 

• Nicot (2008) modeled an injection roughly equivalent to 50 Mt CO2/year for 50 years in an 

area that is hydrologically similar to the Gulf Coast Basin. Model results indicate an average 

water table rise of approximately 1 meter with a minor increase in stream baseflow and a larger 

increase in ground water evapotranspiration. 

ORD's National Center for Environmental Research (NCER) awarded six Science To Achieve 

Results (STAR) grants in the Fall of 2009 to recipients from major universities and institutions 

4
within the scope of the "Integrated Design, Modeling and Monitoring of Geologic Sequestration 

of Anthropogenic Carbon Dioxide to Safeguard Sources of Drinking Water" research area. These 

projects, which started in late 2009, include these lead institutions with specific topics of 

investigation: Clemson University will study potential impacts to drinking water aquifers of 

CO2-rich dissolved brines; the University of Illinois-Urbana will conduct research related to 

reducing hydrologic and geochemical uncertainties associated with CO2 sequestration in deep, 

saline reservoirs; the University of Texas at Austin will assess appropriate monitoring 

approaches at geologic sequestration sites; the University of Utah will integrate design, 

monitoring, and modeling of GS to assist in developing a practical methodology for 

characterizing risks to USDWs; Columbia University will conduct laboratory experiments on 

shallow aquifer systems to improve understanding of geochemical and microbiological reactions 

under low pH/high CO2 stress; and Princeton University will develop a set of computational 

tools to model CO2 and brine movement associated with GS. 

In response to the comment that some state aquifer storage laws do not allow for any water 

displacement, EPA clarifies that the purpose of the Class VI requirements is to ensure the 

appropriate siting of a Class VI well and prevent fluid movement that endangers a USDW. EPA 

notes that the Director has the authority to deny a permit to any project that would violate state 

laws. 

Letter ID: 0172 Comment ID: 23453 Letter Lines: 87 to 94 

Comment Code: 3420 2.2.2.1 Scope of the inventory process (e.g., reliance on publicly 

available information, depth of wells) 

Comment: Drill Holes and Abandoned Wells: 

EPA should consider options to ensure that mineral exploration drill holes and 

abandoned wells are accounted for on the AOR maps. States have serious concerns 

about the ability to account for all of these potential holes and open shear 

zones or faults that may allow migration from the injection zone to the fresh 

water aquifers, as well as leakage out of the geo- sequestration site and back 

into the atmosphere. The AOR should also be periodically reevaluated, 

Individual Response: EPA agrees with the commenter that many factors about a GS site—

including mineral exploration drilling, abandoned wells, and open shear zones or faults—can 

affect containment. EPA believes that the requirement that the AoR and corrective action plan at 

§146.84(b) be based on detailed geologic data collected at the site (including the types of 

information cited by the commenter) will ensure that all potential risks are considered in GS 

permitting decisions. 

EPA adds that the Director has the discretion to require the owner or operator to supplement a 

data records search, including requiring ground or airborne surveys for wells if there is reason to 

believe, based on knowledge of the site or of available databases, that the incompleteness of 

available information could compromise USDW protection. EPA adds that all corrective action 

5
must be performed pursuant to the approved AoR and corrective action plan, which affords the 

Director the discretion to require any additional information needed to ensure that all necessary 

corrective action is performed. 

Letter ID: 0172 Comment ID: 23454 Letter Lines: 94 to 95 

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

Comment: into the atmosphere. The AOR should also be periodically reevaluated, 

particularly as improved predictive models and new data become available. 

Individual Response: EPA agrees with the commenter that periodic AoR reevaluations are 

appropriate. This final rule retains this provision. 

Letter ID: 0172 Comment ID: 23455 Letter Lines: 97 to 114 

Comment Code: 1210 1.1.1 Comments about the proposed rule 

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

Guidelines Needed: 

It would be helpful if additional guidelines were included in the rule to 

provide state regulatory authorities with the ability to determine requirements 

for monitoring, corrective action, record keeping, and liability of carbon 

sequestration injection well sites. Guidelines are needed to help states 

consider baseline geochemical analysis and monitoring data, as well as 

corrective action plans, in the event that a USDW becomes affected by an 

injection well site. Guidelines are also needed to ensure that the long-term 

financial responsibility of owners/operators of injection wells adequately cover 

the potential costs of site closure and stewardship. While the rule should 

provide some minimum requirements for record keeping and the frequency of 

reporting, the rule should also be flexible enough to allow states to address 

site-specific conditions in determining these requirements. Common assumptions 

will need to be tested under the unique conditions of individual sites in order 

to avoid unintended consequences. 

Individual Response: EPA believes that the Class VI requirements balance site-specific 

flexibility with USDW protection. Rather than setting performance or technology-based 

standards for GS projects, EPA is adopting a flexible approach, where operators of GS projects 

would develop and implement site-specific plans for delineating the AoR, testing and monitoring 

the site, performing corrective action, and post-injection site care. EPA believes that the plans—

which would be reviewed and approved by the Director and periodically updated throughout the 

life of the project—promote an ongoing dialogue between the operator and the Director that will 

6
encourage use of the most appropriate technologies for a particular project. 

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: 0172 Comment ID: 23456 Letter Lines: 116 to 126 

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

Comment: State Standards, Regulations, Funding, and Primacy Requirements 

State Flexibility Needed: 

The flexible regulatory approach that is built into the proposed rule appears to 

adequately provide for state implementation efforts to address site specific 

circumstances and assure that the rule is implemented toward the highest degree 

of protection for USDWs. However, the rule should also allow for state 

flexibility with regard to existing state standards and regulations, if they are 

more stringent (i.e., regarding well construction requirements) than the Federal 

rule. 

Individual Response: The Agency believes that the Class VI requirements balance site-specific 

flexibility with USDW protection. Rather than setting performance or technology-based 

standards for GS projects, EPA is adopting a flexible approach, where operators of GS projects 

would develop and implement site-specific plans for delineating the AoR, testing and monitoring 

the site, performing corrective action, and post-injection site care. EPA believes that the plans—

which would be reviewed and approved by the Director and periodically updated throughout the 

life of the project—promote an ongoing dialogue between the operator and the Director that will 

encourage use of the most appropriate technologies for a particular project. 

In response to the comment that States with primacy be able to develop “performance-based 

standards,” the Agency clarifies that States, Tribes, and Territories can develop requirements for 

Class VI and submit primacy applications (under Section 1422 of the SDWA) for review and 

approval by EPA as long as the requirements are as stringent as or more stringent than the 

Federal minimum requirements. 

Letter ID: 0172 Comment ID: 23457 Letter Lines: 128 to 134 

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

7
Comment: State Resources Needed: 

The financial and resource burden on EPA and state primacy agencies to assess 

the geologic sequestration permit submissions, evaluate the technical models, 

and make permitting determinations will be greatly increased by this rule. 

Financial resource considerations should accompany eventual promulgation of the 

rule in order to ensure adequate state funding for these various tasks. 

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: 0172 Comment ID: 23458 Letter Lines: 136 to 141 

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

Comment Code: 5610 2.11.1 Allowing partial primacy for Class VI wells (seeking comment) 

Comment: State Primacy Considerations: 

EPA should investigate options for state primacy considerations under SDWA 1425 

to regulate the new class VI wells for carbon sequestration independently of 

other well classes. As the proposed rule is currently written, it precludes 

states that only have primacy on Class II wells. 

Individual Response: EPA clarifies that Section 1425 of SDWA allows an alternative primacy 

demonstration only for programs regulating injection wells associated with oil and gas recovery 

or natural gas storage. Therefore, wells used for the purpose of GS cannot be covered under 

Section 1425. While EPA acknowledges that states that have not obtained primacy under SDWA 

Section 1422 for other well classes may be less familiar with implementing the UIC program 

under that section of the Act, the Agency does not believe this would preclude their ability to 

effectively obtain and implement primacy for Class VI wells. EPA does not intend to limit 

primacy of Class VI wells to only states with primacy for Class II wells—any state that can 

demonstrate in its primacy application that it has developed regulations that are at least as 

stringent as the minimum Federal requirements (e.g., permitting, inspection, operation, 

monitoring, and recordkeeping requirements) in the final GS rule will be granted primacy for 

Class VI wells. 

EPA also plans to support states as needed to help them develop and implement their Class VI 

programs. EPA will allow states to apply for primacy for Class VI independently of other well 

8
9

classes regardless of whether or not they have primacy for other well classes. EPA is developing 

guidance materials and plans to conduct on-line and in-person training for States, Tribes, and 

Territories to 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.