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.
Department of Environmental Quality

To protect, conserve and enhance the quality of Wyoming's

environment for the benefit of current and future generations.

Dave Freudenthal, Governor

Water Docket

Environmental Protection Agency

Mailcode: 2822T

1200 Pennsylvania Ave., NW

Washington, DC 20460

John Corra, Director

Re: Wyoming Department ofEnvironmental Quality Comments on the Federal Requirements

Under the Underground Injection Control ([lIe) Programfor Carbon Dioxide (C02) Geologic

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

To Whom it May Concern:

On behalf ofthe Wyoming Department ofEnvironmental Quality I 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.

General Comments:

1. Funding: It is essential that the US EPA provide adequate funding to states assuming

primacy jurisdiction under the UIC program to administer C02 storage regulatory

activities. EPA funding to states to administer federal environmental programs, such as

UIC, continues to decline in terms ofreal dollars. Recognizing the scope ofwork

anticipated for C02 sequestration in this country alone, substantial additional skills and

resources will be required at the state level in order to develop and implement effective

permitting and oversight programs. It is imperative that EPA recognize that need and

begin to establish special provisions to set aside funds that states and tribes, will need to

operate those programs.

2. Primacy for Class VI Wells: The US EPA should allow for separate delegation of

primacy to the states and tribes for Class VI wells unless the state or tribe requests that

the delegation be made part oftheir existing UIC program for Class I, II, III or V wells.

3. Permit Fees: The US EPAshould consider a permit fee formula for Class VI wells that is

sufficient to support state, tribal, and permitting programs, provides consistency offee

amounts between such programs, and provides certainty offee expenses to those

interested in or applying for a Class VI permit.

ADMIN/OUTREACH

(307) 777-7937

FAX 777-3610

Herschler Building • 122 West 25th Street • Cheyenne, WY 82002 • http://deq.state.wy.us

ABANDONED MINES AIR QUALITY INDUSTRIAL SITING LAND QUALITY SOLID & HAZ. WASTE WATER QUALITY

(307) 777-6145 (307) 777-7391 (307) 777-7369 (307) 777-7756 (307) 777-7752 (307) 777-7781

FAX 777-6462 FAX 777-5616 FAX 777-5973 FAX 777-5864 FAX 777-5973 FAX 777-5973
4. Training: The U.S. EPA should establish, on a regional level, training programs that

assist in building state's capacity in the science and technology necessary to effectively

regulate C02 sequestration.

Specific Comments:

1. Prohibiting C02 injection into formations ifthey are above the lowermost USDW:

a. We believe it's imperative that the Director be allowed discretion to allow

injection above or between USDWs in specific geologic settings Where the depth

ofthe USDWs may preclude geologic sequestration, make Geologic

Sequestration (GS) technically challenging, or significantly limit C02 storage

capacity." Such approval by the Director would allow injection between USDWs

(and thereby allowing injection above the lowermost USDW) in circumstances in

which it can be demonstrated that USDWs would not be endangered.

b. Furthermore, we support providing Direc.tors the flexibility and discretion to:

1. Exempt all USDWs below the injection zone (if necessary to meet a

requirement that injection is only allowed beneath the deepest USDW).

11. Exempt aquifers for the purpose ofC02 injection in accordance with the

.requirements of 40 CFR 144.7.

111. Exempt aquifers for the purpose ofC02 injection in accordance with the

requirements of 40 CFR 146.4.

c. In the event that aquifer exemptions are not feasible, we urge the US EPA to

allow C02 injection into aquifers previously exempted for Class I and Class II

injection operations, provided thatthe operator obtains a new aquifer exemption

for the purpose of GS.

2. Requiring a minimum depth ofinjection:

a. Given the variety in subsurface geologic conditions that exist both within, and

between states, we would not support setting a minimum injection depth

requirement for C02 GS in lieu ofrequiring that such injection take place below

the lowermost USDW.

3. Prohibiting the injection ofC02 for long-term storage into coal seams where they are

above the lowermost USDW:

a. We believe there are likely circumstarices where injection into formations

(including deep, unmineable coal seams) situated above the lowermost USDW

may be practical and protective of overlying and underlying USDWs.
4. Requiring a fixed timeframe post-injection site care (monitoring) period of 50 years:

a. We recommend that a performance standard be applied to determine the period of

post-injection site care - that post-injection site care continues until the plume is

stabilized and will not endanger USDWs.

b. We recommend that the Director should be provided discretion to shorten or

lengthen the proposed post-injection site care period of 50 years accordingly.

5. Not allowing for the use ofseparate financial demonstrations to be submitted for the

plugging ofthe injection well and for the post-injection site care requirements:

a. It may be advantageous to require the approval ofthe well plugging financial

demonstration at permit issuance and the post-injection site care financial

demonstration at a later time (e.g., within 180 days of notifying the Director that

the well will be plugged and abandoned.). We recommend that the regulation

provide for accepting separate financial demonstrations not only for well plugging

and post-injection site care phases, but for the other operational and nonoperational phases of GS, including Operation/Injection,

Monitoring/Measurement/Verification, etc., as may be necessary.

6. Various issues where we agree with US EPA that the Director should have the discretion

to determine, or require:

a. Grandfathering the construction requirements for existing Class I and Class II

wells seeking a permit for geologic sequestration ofC02, provided that they

conform to Class VI requirements as proposed in the regulation.

b. Identifying and characterizing additional confining and containment zones above

the primary (i.e., lowermost) confining zone that could further impede vertical

fluid movement and allow for pressure dissipation.

c. Allowing for the use of proprietary models.

d. Allowing for a phased approach to corrective action.

7. Permit application content:

a. We agree with the US EPA that permit applications for GS sites should include

several plans not currently required under existing UIC regulations. These plans

include a monitoring and testing plan, an AoR and corrective action plan, and a

post-injection site care and site closure plan.
Please feel free to contact me directly at 307-777-7192 should you have any questions regarding

these comments. Thank you. .

Sincerely,

~v:~

J"V. ~orra, Director

Wyoming Department ofEnvironmental Quality

NC/KDF/rm/8-1035

c: Governor David Freudenthal

Don Likwartz, Director, Wyoming Oil and Gas Conservation Commission

Ron Surdam, State Geologist .

John Wagner, Administrator, Water Quality Division

Kevin Frederick, Manager, Groundwater Section, Water Quality Division'
Letter ID: 0205 

Commenter: John Corra 

Organization: Wyoming Department of Environmental Quality (DEQ) 

Letter ID: 0205 Comment ID: 22189 Letter Lines: 31 to 40 

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

Comment: 1. Funding: It is essential that the US EPA provide adequate funding to states 

assuming primacy jurisdiction under the UIC program to administer CO2 storage 

regulatory activities. EPA funding to states to administer federal environmental 

programs, such as UIC, continues to decline in terms of real dollars. 

Recognizing the scope of work anticipated for CO2 sequestration in this country 

alone, substantial additional skills and resources will be required at the state 

level in order to develop and implement effective permitting and oversight 

programs. It is imperative that EPA recognize that need and begin to establish 

special provisions to set aside funds that states and tribes, will need to 

operate those programs. 

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: 0205 Comment ID: 22190 Letter Lines: 42 to 45 

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

Comment: 2. Primacy for Class VI Wells: The US EPA should allow for separate delegation 

of primacy to the states and tribes for Class VI wells unless the state or tribe 

requests that the delegation be made part of their existing UIC program for Class 

I, II, III or V wells. 

Individual Response: EPA agrees with commenters that states should be allowed to obtain 

primacy for Class VI wells independently of other well classes, and will allow independent 

primacy for Class VI wells under §145.1(i) of the final GS rule. Given the potential for CCS 

(encompassing capture, transportation, and geologic sequestration) to be an important part of a 

national priority to address climate change, EPA believes that providing states the flexibility to 

obtain primacy for Class VI wells independently of other well classes can help foster effective 

1
management of CCS. EPA believes that allowing independent Class VI primacy may encourage 

states to take responsibility for implementation of Class VI regulations and provide for a more 

comprehensive approach to managing CCS projects by promoting the integration of GS activities 

under SDWA into a broader framework for managing CCS. Furthermore, GS operations involve 

ancillary activities (e.g., pipeline operations, pore space ownership, land use rights, and surface 

access) for which states can call upon other authorities that exist at the state level (but outside 

UIC authority) to provide a more comprehensive CCS management approach. 

The Agency believes that it is important for states to use their unique efficiencies to promote 

adoption of this burgeoning and important technology, while assuring that USDWs are protected 

from endangerment through the UIC regulatory framework. EPA believes that, due to the 

importance of implementing an effective, comprehensive, and seamless CCS program, States 

should be provided the flexibility to obtain primacy for Class VI only. 

EPA also believes that allowing states to apply only for Class VI primacy will shorten the 

primacy approval process for states. EPA's willingness to accept independent primacy 

applications for Class VI wells represents a shift in its longstanding policy of discouraging 

"partial primacy." It is very important to note that this shift in policy allowing for Class VI 

primacy does not apply to any other well Class under Section 1422. EPA will continue to 

discourage applications for partial primacy for all other well types under Section 1422. 

EPA clarifies that states should be able to obtain primacy for Class VI wells independent of other 

well classes provided they develop regulations that are at least as stringent as the minimum 

Federal requirements (e.g., permitting, inspection, operation, monitoring, and recordkeeping 

requirements) provided in the final GS rule. EPA believes that existing programs can adapt their 

expertise to the new requirements for Class VI wells and will be able to develop a primacy 

application for Class VI wells under section 1422 of SDWA and ensure that their GS programs 

integrate into national climate change priorities and protect USDWs from endangerment. 

Letter ID: 0205 Comment ID: 22191 Letter Lines: 47 to 51 

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

ownership 

Comment: 3. Permit Fees: The US EPA should consider a permit fee formula for Class VI 

wells that is sufficient to support state, tribal, and permitting programs, 

provides consistency of fee amounts between such programs, and provides 

certainty of fee expenses to those interested in or applying for a Class VI 

permit. 

Individual Response: EPA clarifies that it does not have authority to set permit fees for Class 

VI well owners or operators under SDWA. 

EPA recognizes that states may face 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 

2
challenges associated with GS. EPA will also incorporate Class VI GS 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: 0205 Comment ID: 22192 Letter Lines: 53 to 55 

Comment Code: 1435 1.2.1.3 EPA should develop guidance 

Comment Code: 1530 1.2.3.1 State regulatory efforts on GS (seeking comment) 

Comment: 4. Training: The U.S. EPA should establish, on a regional level, training 

programs that assist in building state's capacity in the science and technology 

necessary to effectively regulate CO2 sequestration. 

Individual Response: EPA is developing guidance materials and plans to conduct on-line and 

in-person training for states and tribes that describes 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 associated with developing GS 

regulations that are the equivalent of minimum federal criteria and requirements. These are 

available on EPA’s website at 

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

Letter ID: 0205 Comment ID: 22193 Letter Lines: 59 to 68 

Comment Code: 4410 2.4.4.3.1 Comments in favor of allowing injection above/between 

USDWs in certain circumstances 

Comment: 1. Prohibiting CO2 injection into formations if they are above the lowermost 

USDW: 

a. We believe it's imperative that the Director be allowed discretion to allow 

injection above or between USDWs in specific geologic settings Where the depth 

of the USDWs may preclude geologic sequestration, make Geologic Sequestration 

(GS) technically challenging, or significantly limit CO2 storage capacity." Such 

approval by the Director would allow injection between USDWs (and thereby 

allowing injection above the lowermost USDW) in circumstances in which it can be 

demonstrated that USDWs would not be endangered. 

Individual Response: EPA acknowledges that there are limited circumstances where injection 

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

endangerment, as long as appropriate protections are in place. The final GS rule at §146.95 

establishes a process by which owners or operators can seek a waiver of the Class VI injection 

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

Determinations about the appropriateness of a waiver would be made by the Director, based on 

3
evaluation of site-specific conditions. 

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

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

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

capacity limitations imposed by the proposed injection depth requirements; 2) allows for a more 

site-specific assessment of injection depth for GS projects; 3) accommodates injection into 

different formation types; 4) allows for injection of CO2 for GS into non-USDWs above and/or 

between USDWs when appropriate and where it can be demonstrated that USDWs will be 

protected; and 5) responds to concerns about the use of aquifer exemptions for GS. Finally, 

EPA’s approach to addressing injection depth variability through a waiver process responds to 

concerns about future drinking water resource availability and the need to ensure that high 

quality water remains available in sufficient quantities to supply drinking water needs. For 

additional information on the waiver approach for Class VI wells, 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. 

Letter ID: 0205 Comment ID: 22195 Letter Lines: 70 to 74 ; 76 to 85 

Comment Code: 4320 2.4.4.1 Injection beneath the lowermost formation containing a USDW 

Comment Code: 4460 2.4.4.4.1 Comments in favor of allowing aquifer exemptions in certain 

circumstances 

Comment: b. Furthermore, we support providing Directors the flexibility and discretion 

to: 

i. Exempt all USDWs below the injection zone (if necessary to meet a requirement 

that injection is only allowed beneath the deepest USDW). 

ii. Exempt aquifers for the purpose of CO2 injection in accordance with the 

requirements of 40 CFR 144.7. 

iii. Exempt aquifers for the purpose of CO2 injection in accordance with the 

requirements of 40 CFR 146.4. 

c. In the event that aquifer exemptions are not feasible, we urge the US EPA to 

allow CO2 injection into aquifers previously exempted for Class I and Class II 

injection operations, provided that the operator obtains a new aquifer exemption 

for the purpose of GS. 

Individual Response: EPA acknowledges that there are limited circumstances where aquifer 

exemptions for GS may be warranted. The final rule allows for the expansion of the areal extent 

of existing aquifer exemptions for Class II EOR/EGR wells transitioning to Class VI injection 

for GS pursuant to requirements at §§146.4 and 144.7(d). Class VI owners or operators granted 

expansions of existing Class II EOR/EGR aquifer exemptions for GS projects must meet all of 

the tailored requirements for GS wells in the final GS rule. 

4
EPA clarifies that all decisions regarding whether expansion of existing aquifer exemptions will 

be at the Director's discretion and based on site-specific information. 

EPA adds that the final rule precludes the issuance of new aquifer exemptions for Class VI GS 

wells. Aquifer exemptions will only be granted for projects that are transitioning from Class II 

EOR/EGR wells to Class VI. Aquifer exemption expansions are limited to Class II EOR/EGR 

wells transitioning to Class VI injection for GS. The aquifer exemption requirements in the final 

rule provide flexibility and afford owners or operators an opportunity to assess and select a 

suitable GS site while also preserving USDWs (i.e., formations/aquifers afforded SDWA 

protection). Class VI owners or operators granted expansions of existing Class II EOR/EGR 

aquifer exemptions for GS projects must meet all of the tailored requirements for GS wells in the 

final GS rule. 

For additional information on aquifer exemptions for Class VI wells, 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. 

Letter ID: 0205 Comment ID: 22196 Letter Lines: 87 to 92 

Comment Code: 4344 2.4.4.2.2 Comments opposed to setting a minimum injection depth 

Comment: 2. Requiring a minimum depth of injection: 

a. Given the variety in subsurface geologic conditions that exist both within, 

and between states, we would not support setting a minimum injection depth 

requirement for CO2 GS in lieu of requiring that such injection take place below 

the lowermost USDW. 

Individual Response: EPA agrees that it is not appropriate to set a minimum injection depth for 

GS projects and the Agency believes that a determination of site-suitability for GS (i.e., that 

subsurface formations will receive and confine injected CO2) should be made on a site-specific 

basis. The GS rule, at §146.82, requires the owner or operator to provide extensive site- and 

project-specific information to the Director to demonstrate that the site meets the minimum site 

criteria at §146.83, that the CO2 will be contained within the injection formation, and that 

USDWs will be protected from endangerment. 

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

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

are in place. The final GS rule at §146.95 establishes a process by which owners or operators can 

seek a waiver of the Class VI injection depth requirements for injection into non-USDW 

formations above and/or between USDWs. The waiver approach requires the submission of 

extensive, site-specific information (in conjunction with the permit application submission) to 

demonstrate that injection of CO2 into a non-USDW that is above or between USDWs can be 

done in a manner that is protective of USDWs. The requirements are designed to ensure that the 

owner or operator, the Director, and the Regional Administrator consider, on a site specific basis, 

5
the implications, benefits, and challenges associated with GS and ensuring water availability and 

USDW protection. For additional information on the waiver approach, please see the final rule 

and preamble, as well as EPA's responses to comments on the Notice of Data Availability and 

Request for Comment. 

Letter ID: 0205 Comment ID: 22197 Letter Lines: 94 to 99 

Comment Code: 4430 2.4.4.3.3 Injection into coal seams above USDWs (seeking comment) 

Comment: 3. Prohibiting the injection of CO2 for long-term storage into coal seams where 

they are above the lowermost USDW: 

a. We believe there are likely circumstances where injection into formations 

(including deep, unmineable coal seams) situated above the lowermost USDW may be 

practical and protective of overlying and underlying USDWs. 

Individual Response: The final GS rule does not categorically preclude or prohibit injection 

into any type of formation, including coal seams. Instead, the requirements are designed to 

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

operation, monitoring, and PISC at all sites selected for GS. 

EPA recognizes that some types of formations, such as coal seams and basalts, are typically 

shallow and above the lowermost USDW. EPA expects that most injection wells conducting GS 

in these shallow formations will be permitted as Class VI wells and such wells will be issued 

waivers, provided that their owners or operators can meet all of the requirements for an injection 

depth waiver at §146.95 and demonstrate that such injection can be performed in a manner that 

protects USDWs, as long as appropriate protections are in place. The Class V experimental 

technology well classification, may, in some instances be an appropriate permitting alternative. 

This decision should be informed through a discussion between the injection well owner or 

operator and the Director to determine the purpose and proper design of the well. 

For additional information on the waiver approach and aquifer exemptions for Class VI wells, 

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. 

Letter ID: 0205 Comment ID: 22198 Letter Lines: 101 to 109 

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

Comment Code: 5260 2.8.2.3 Adjusting the post-injection timeframe (seeking comment) 

Comment: 4.Requiring a fixed timeframe post-injection site care (monitoring) period of 50 

years: 

a.We recommend that a performance standard be applied to determine the period of 

post-injection site care -that post-injection site care continues until the 

6
plume is stabilized and will not endanger USDWs. 

b. We recommend that the Director should be provided discretion to shorten or 

lengthen the proposed post-injection site care period of 50 years accordingly. 

Individual Response: 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 GS rule offers owners or operators flexibility 

regarding the duration of the PISC timeframe by: (1) allowing the Director discretion to shorten 

or lengthen the PISC timeframe during the post-injection period based on site-specific data, 

pursuant to requirements at §146.93(b); or (2) affording the Director discretion to allow a Class 

VI well owner or operator to demonstrate, during the permitting process based on substantial 

data, that an alternative PISC timeframe may be appropriate if it ensures non-endangerment of 

USDWs pursuant to requirements at §146.93(c). 

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

for post-injection site care will be necessary in all but a limited number of cases. This default 50 

year post-injection site care timeframe represents a reasonable and protective monitoring period 

based on a review of research studies, industry reports, and existing environmental programs, 

and evaluation of public comments. 

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

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

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

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

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

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

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

impacts. 

Letter ID: 0205 Comment ID: 22199 Letter Lines: 111 to 122 

Comment Code: 5436 2.9.1.3 Allowing separate financial demonstrations for plugging and 

abandonment and post-injection site care (seeking comment) 

Comment: 5. Not allowing for the use of separate financial demonstrations to be submitted 

for the plugging of the injection well and for the post-injection site care 

requirements: 

a. It may be advantageous to require the approval of the well plugging financial 

demonstration at permit issuance and the post-injection site care financial 

demonstration at a later time (e.g., within 180 days of notifying the Director 

that the well will be plugged and abandoned.). We recommend that the regulation 

provide for accepting separate financial demonstrations not only for well 

plugging and post-injection site care phases, but for the other operational and 

nonoperational phases of GS, including Operation/Injection, 

7
Monitoring/Measurement/Verification, etc., as may be necessary. 

Individual Response: In the final rule, owners or operators are required to demonstrate, with 

their permit application, adequate financial responsibility for specific GS activities, including 

plugging and post-injection site care, per §146.85(a). EPA clarifies at §146.85(a)(6) that, prior to 

obtaining a Class VI permit, an owner or operator may demonstrate financial responsibility by 

using one or multiple qualifying financial instruments for specific GS activities, thereby realizing 

greater flexibility and cost savings from this regulation. In the event that the owner or operator 

combines more than one instrument for a specific GS activity (e.g., well plugging), such 

combination must be limited to instruments that are not based on financial strength or 

performance (i.e., self insurance or performance bond), for example trust funds, surety bonds 

guaranteeing payment into a trust fund, letters of credit, escrow account, and insurance. In this 

case, it is the combination of instruments, rather than the single instrument, which must provide 

financial responsibility for an amount at least equal to the current cost estimate. 

Additionally, EPA is developing guidance (available on EPA's website at 

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm) that describes the types of 

financial instruments that owners or operators can use to meet financial responsibility 

requirements for Class VI wells; this guidance will also address how different instruments may 

be applied for various GS activities. 

Letter ID: 0205 Comment ID: 22200 Letter Lines: 124 to 129 

Comment Code: 2060 1.5.3 Comments on grandfathering of existing wells (seeking comment) 

Comment: 6. Various issues where we agree with US EPA that the Director should have the 

discretion to determine, or require: 

a. Grandfathering the construction requirements for existing Class I and Class 

II wells seeking a permit for geologic sequestration of CO2, provided that they 

conform to Class VI requirements as proposed in the regulation. 

Individual Response: EPA agrees that many Class I, Class II, and Class V experimental 

technology wells are designed and constructed to withstand exposure to CO2. The final GS rule 

allows the construction of these wells to be grandfathered per §146.81(c), provided the owner or 

operator can demonstrate to the Director that the wells were engineered and constructed to meet 

the requirements at §146.86(a) and ensure protection of USDWs, in lieu of requirements at 

§146.86(b) and §146.87(a). EPA clarifies that only the construction requirements are 

grandfathered and that all other Class VI requirements (reporting, monitoring, mechnical 

integrity testing, etc.) must be met following a determination under §146.81(c). 

Conversion of the well is at the Director's discretion following an evaluation of all other sitespecific information about the well and the project, e.g., modeling, monitoring, and other data 

under §146.81. Any wells that have deteriorated due to contact with incompatible injected or 

formation fluids may not be approved for conversion. 

8
Letter ID: 0205 Comment ID: 22201 Letter Lines: 124 to 125 ; 131 to 133 

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

(seeking comment) 

Comment: 6. Various issues where we agree with US EPA that the Director should have the 

discretion to determine, or require: 

b.Identifying and characterizing additional confining and containment zones 

above the primary (i.e., lowermost) confining zone that could further impede 

vertical fluid movement and allow for pressure dissipation. 

Individual Response: EPA agrees with the commenter that, in some situations, the presence of 

additional confining and containment zones above the primary (i.e., lowermost) confining zone 

can improve USDW protection from endangerment. The final regulation retains the requirement 

at §146.83(b) which affords the Director discretion to require owners or operators to identify and 

characterize additional zones. 

Letter ID: 0205 Comment ID: 22202 Letter Lines: 124 to 125 ; 135 to 135 

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

Comment: 6. Various issues where we agree with US EPA that the Director should have the 

discretion to determine, or require: 

c. Allowing for the use of proprietary models. 

Individual Response: EPA agrees that some of the available proprietary models may meet the 

needs for calculating the AoRs of GS sites. EPA will allow their use in meeting the requirements 

for the GS regulation, but clarifies that GS well operators using proprietary models are required 

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

basis. EPA acknowledges that several proprietary models have been used by petroleum-reservoir 

engineering professionals as well as in peer-reviewed studies to model CO2 sequestration. 

Information including model assumptions and equations are used by the Director to inform 

his/her decision to issue the permit and ensure that the requirements are met and the GS well will 

not endanger USDWs. EPA adds that its Confidential Business Information requirements at 40 

CFR 144.5 will apply to the use of proprietary models. 

Letter ID: 0205 Comment ID: 22203 Letter Lines: 124 to 125 ; 137 to 137 

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

Comment: 6. Various issues where we agree with US EPA that the Director should have the 

discretion to determine, or require: 

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d. Allowing for a phased approach to corrective action. 

Individual Response: EPA agrees that there are potential benefits to phased corrective action, 

including distributing the burden and costs of corrective action over time and not delaying 

initiation of the GS project. 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. 

However, EPA recognizes that a phased approach to corrective action may not be appropriate in 

all situations, and that the Director is in the best position to make decisions about the 

appropriateness of phased corrective action based on his or her knowledge of the local geologic 

and site conditions. For this reason, the GS rule affords the Director discretion in determining 

whether phased corrective action is appropriate at a given GS site. 

Letter ID: 0205 Comment ID: 22204 Letter Lines: 139 to 144 

Comment Code: 4610 2.6.1 Testing and monitoring plan requirement (seeking comment) 

Comment Code: 4710 2.7.1 Proposed submissions required for permit applications (seeking 

comment) 

Comment: 7. Permit application content: 

a. We agree with the US EPA that permit applications for GS sites should include 

several plans not currently required under existing UIC regulations. These plans 

include a monitoring and testing plan, an AoR and corrective action plan, and a 

post-injection site care and site closure plan. 

Individual Response: EPA agrees with commenters that developing and following testing and 

monitoring plans is an important part of assuring that a GS project is operating properly and is 

crucial for the early detection of potential endangerment to USDWs. The final rule retains this 

requirement. 

EPA agrees that incorporating the plans into the permit rather than establishing specific 

requirements for corrective action, monitoring, injection well plugging, and post-injection site 

care in the regulation provide the appropriate flexibility to address the variety of site-specific 

conditions that may be encountered at GS sites. 

EPA believes that it is appropriate and necessary to require owners and operators to submit all 

plans, including the injection well plugging and post-injection site care and site closure plans, at 

the time of permit application for the Director to make a proper permit decision. EPA believes 

that the Director needs a satisfactory level of assurance that the owner or operator has planned 

for these events before injection commences and that the owner or operator has ensured that 

appropriate financial resources are available to fund all required activities, as required at 

§146.85. The final rule retains requirements for submitting these plans with the permit 

application at §146.82(a). EPA expects that the requirement for this and other plans associated 

with GS projects will promote an ongoing dialogue between the owner or operator and the 

Director to ensure USDWs are protected from endangerment. In addition, these plans will 

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support a demonstration under §146.85 that owners and operators have adequate financial 

resources to meet well plugging and post-injection site care and site closure requirements. Please 

see the final rule and the discussion of the GS project plans for additional information.