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.
November 17, 2008 

U.S. Environmental Protection Agency 

Water Docket 

Attention: Docket # EPA-HQ-OW-2008-0390 

Mailcode: 2822T 

1200 Pennsylvania Ave, NW 

Washington, DC 20460 

To Whom It May Concern: 

The Commonwealth of Pennsylvania’s Department of Environmental Protection (DEP) and 

Department of Conservation and Natural Resources (DCNR) are pleased to provide comments on the 

U.S. Environmental Protection Agency’s (EPA) proposed rule, “Federal Requirements Under the 

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

Wells,” published for comment on July 25, 2008, at 73 Federal Register 43492. 

 Section 27 (relating to natural resources and the public estate) of the Pennsylvania Constitution 

declares that, “The people have a right to clean air, pure water, and to the preservation of the natural, 

scenic, historic, and esthetic values of the environment. Pennsylvania’s public natural resources are the 

common property of all the people, including generations yet to come. As trustee of these resources, the 

Commonwealth shall conserve and maintain them for the benefit of all the people.” 

 Geologic sequestration of CO2 would have to be conducted in a manner that complied with the 

laws and regulations of the Commonwealth. Although Pennsylvania does not have specific groundwater 

protection statutes, the Clean Streams Law provides the legal framework for managing the groundwater 

quality in the waters of the Commonwealth. The Pennsylvania Clean Streams Law, Act of 1937, 

P.L. 1987, as amended in 1989, provides for preservation and improvement of the waters of the 

Commonwealth for the protection of public health, animal and aquatic life, and/or industrial 

consumption, and recreation. The Act states that “...the waters of the Commonwealth shall be 

construed to include any and all rivers, streams, creeks, rivulets, impoundments, ditches, and other 

bodies or channels of conveyance of surface and underground (emphasis added) water, or parts thereof, 

whether natural or artificial, within or on the boundaries of the Commonwealth.” Through the Clean 

Streams Law and specific program regulations, the goals and standards are integrated with all other state 

water quality and environmental goals. Specifically, 35 PA Code chapter 91.51 and chapter 91.52 

prohibit disposal of wastes underground by means that pose a threat to underground sources of drinking 

water. 

 Act 70 of 2008, the Pennsylvania Climate Change Act, requires DEP to establish a permanent 

climate change advisory committee, designate voluntary emissions and offset registries, establish annual 

greenhouse gas inventories, develop an impacts assessment that identifies both scientific and economic 

impacts to Pennsylvania from climate change, and create a climate change mitigation action plan. The 

inventories, impacts assessment, and climate change action plan are to be presented to the General 
U.S. Environmental Protection Agency - 2 - November 17, 2008 

Assembly and Governor, and are to be updated every three years. Currently, DEP is working with the 

climate change advisory committee to comply with Act 70. 

 Act 129 of 2008, amending the Title 66 (Public Utilities) of the Pennsylvania Consolidated 

Statues, requires DCNR to conduct studies of carbon capture and sequestration, and present its findings 

to the Governor and the General Assembly by mid-to-late 2009. The studies will include: 

(1) Identification of suitable geological formations for the location of a CO2 sequestration 

network (due May 1, 2009); and 

(2) An independent assessment (due November 1, 2009) of the following: 

a) Costs to establish, operate, and maintain a CO2 sequestration network; 

b) Safety and potential risk to individuals, property, and the environment associated 

with the geological sequestration of CO2;

c) Existing federal and state regulatory standards for the storage of CO2; 

d) Factors contained in the U.S. EPA’s vulnerability evaluation framework for 

geologic sequestration of CO2; 

e) Different types of insurance, bonds, other instruments and recommended levels of 

insurance which should be carried by an operator of a state network during 

construction and operation, and availability of commercial insurance; 

f) Models for the establishment of a Commonwealth fund to provide protection 

against risk. 

Following review of the above, Act 129 authorizes DCNR to conduct a pilot project to determine the 

viability of establishing a network in Pennsylvania that facilitates carbon capture, pipeline transmission, 

and geologic sequestration. 

 The government of the Commonwealth of Pennsylvania is committed to preserving the natural 

resources and public estate afforded to the people of Pennsylvania. Both DEP and DCNR are interested 

in the greenhouse gas reduction opportunities that responsible carbon capture and storage may present. 

However, these opportunities should be approached with a clear understanding of the potential risks and 

must only be pursued with the best tools-in-hand to mitigate such risks. The DEP and DCNR believe 

that EPA’s proposed rule represents a solid effort to categorize and prevent some of the potential risks to 

underground sources of drinking water (USDW) that are associated with carbon capture and storage. 

The DEP and DCNR appreciate the opportunity to comment on this proposed rule. 

Proposed Class VI Permit Requirements

• The permit applicant (owner/operator) for a proposed UIC Class VI well must demonstrate in the 

permit application that he owns the right to inject the CO2 into the property and that his 

ownership extends to the entire area to which the CO2 may migrate. 

• Section 146.82 sets forth the information which the owner or operator must submit... 

“(b) A map showing the injection well(s) for which a permit is sought and the applicable area 

of review. Within the area of review, the map must show... Only information of public 

record is required (emphasis added) to be included on this map;....” 
U.S. Environmental Protection Agency - 3 - November 17, 2008 

While it may be prudent to show only public information, it is also easy to avoid the aggravation 

of a diligent search by requiring that only public information is shown. This should not relieve 

the permittee from sharing any confidential information about the area, the subsurface 

conditions, the potential adjoining landuse, etc. Regulations should require full and complete 

disclosure of all information known, even if a confidential submittal is required. 

• It is possible that the owner/operator would be required to obtain information from neighboring 

non-owners in order to meet the requirements identified in the permit requirement and or area of 

review sections. EPA should identify the means by which Class VI owners/operators can obtain 

this information. This point is especially relevant to the inclusion of ‘buffer zones’ (see 

comments on the Area of Review) and the need to obtain site-specific information about these 

buffers.

Proposed Geologic Siting Requirements

• The proposed regulations should better express the need for characterizing the number, location, 

and depth of “underground sources of drinking water.” Specifically, Pennsylvania recommends 

the addition of a subsection under “Geologic Siting Requirements” that calls for a hydrogeologic 

characterization of USDWs in the area of review. Although a number of technical requirements 

for such a characterization are presented in the Technical Support Document, “Geologic CO2

Sequestration Technology and Cost Analysis,” such visibility is not present in the proposed rule 

itself. The depth and capacity of the regional groundwater system should be established in this 

characterization, along with other required details described in the Technical Support 

Documents. Groundwater flow directions and approximate water budgets to estimate deep 

components of flow will help to assess any injection well impacts to USDWs. Fracturing and 

faulting in context with the regional groundwater system should be a part of the hydrogeologic 

characterization. This would include an uncertainty analysis of current knowledge for the area. 

Also, consideration should be given for a recommendation of scales for maps and cross sections. 

Scales should be sufficient to provide enough detail for the “detailed geologic assessment.” 

• The definition and criteria to ‘show or demonstrate secondary containment of the reservoir’ does 

not make sense for PA geology. EPA should allow for demonstration approaches that are 

flexible to regional geology. 

Proposed Area of Review and Corrective Action Requirements

• PA needs to be assured that the designated “Area of Review” is sufficient and inclusive to 

provide for sound analysis of the impacts and control of potential environmental impacts to 

groundwater, water supplies, and surface water. State complications may arise from property 

and mineral rights related to permitting and operations of the proposed Class VI regulations 

based on this definition and its application. 

• Area of Review should include a “buffer zone” surrounding the Area of Review boundary that is 

adequate to address risk of improper assessment. The size of the boundary should be left to the 

applicant but should be subject to the Director’s approval. 
U.S. Environmental Protection Agency - 4 - November 17, 2008 

• The proposed rule discusses multiphase modeling and considers them appropriate for 

hydraulically connected formations being used by different operators. Where there are multiple 

operators injecting into a formation that is hydraulically connected, rules should require an 

evaluation of the chemical reaction of the different injections, unless they are chemically the 

same, as well as their interaction with native fluids. 

• Proprietary models should not be acceptable for use because of the complex nature of the activity 

and the many unknowns. Through a transparent process, EPA should maintain minimum 

modeling standards and assumptions required for approval. 

• The rule proposes phased corrective action (plugging of existing penetrations) after injection 

begins, but the corrective action is to occur in advance of the CO2 plume. The rule should 

require all corrective action to occur before injection begins, or, if phased corrective action is to 

be approved, then the operator must post a 100 percent performance bond with the permitting 

agency before the permit is issued. The performance bond is to be in the amount necessary for 

the permitting agency to immediately complete the corrective action should the owner/operator 

fail to do so in a timely manner. 

Proposed Injection Well Operating Requirements

• Appropriate deed restrictions and surface controls should be required to be implemented by the 

owner/operator to prevent another person from compromising the integrity of the confinement 

zone. 

• Language is included in the proposed rule detailing how the injection well will be monitored 

during its operation, but there is no language included that regulates the monitoring of areas 

surrounding the injection well. There is also concern about how deep and how close to the 

capping (sealing) formation the surrounding monitoring wells and other wells should be allowed 

to approach the capping formation. 

Proposed Mechanical Integrity Testing Requirements

• “Section 146.89 Mechanical integrity. 

(a) A Class VI well has mechanical integrity if: 

 (1) There is no significant leak in the casing, tubing or packer; and 

 (2) There is no significant fluid movement into a USDW through channels adjacent 

to the injection well bore. 

(b) To evaluate the absence of significant leaks under paragraph (a)(1) of this section, owners 

or operators must....” 

There is no definition of “significant” in the document. A definition should be included that 

explains how the term will be defined, such as some measurement around a mean, a variance 
U.S. Environmental Protection Agency - 5 - November 17, 2008 

interval, etc. Too often the term is used without an understanding of its technical meaning. This 

will also help the permittee to understand what is expectated. 

• ‘De minimus’ CO2 leakage values should be determined and defined, as well as the acceptable 

measurement methodology and verification practices. 

Proposed Plume and Pressure Front Monitoring Requirements

• EPA should specifically identify (by technology) what type of monitoring would be necessary 

and applicable to verify containment of the CO2 and any failures away from the injection wells 

themselves.

• Depending on the geology surrounding the containment formation, it is possible that the CO2

could be absorbed/adsorbed by some of the surrounding formations. This could cause a drop in 

pressure not directly associated with leakage. EPA should determine or allow for a maximum 

allowable pressure drop, or correction value, dependent on the appropriate surrounding geology.

• EPA should identify specific technologies or processes that will enable operators or owners to 

verify that the CO2 is moving the way in which the models indicated.

• EPA should identify existing methods for remediation of a rogue CO2 plume.

Proposed Recordkeeping and Reporting Requirements

• The chemistry of the gas stream will be affected by the fuel source and the operating conditions 

of the capture and purification systems. These data, while not the responsibility of the operator, 

can have significant impacts on the gas constituents. Semi-annual reports will not be timely in 

identifying these impacts. The operator should require reports from the gas source, which can be 

forwarded to EPA as part of the semi-annual report, or as an additional submittal between the 

semi-annual reports. Once parameters of operations are known, the reports could be waived or 

modified. A specific example of a potential concern: Power Plant A receives a modification to 

its air permit from a non-primacy state. The modification allows the burning of petcoke, which 

commonly has a high vanadium content. Vanadium oxides can form on operating surfaces, 

affecting capture system efficiencies, or possible modifying down-hole behavior. This type of 

change could greatly affect the overall system. 

Also, operating performance of the gas suppliers’ systems should be monitored. Changes in 

characteristics such as pressure drop, filter cloth efficiencies, increases or changes in dilution air, 

etc., can affect the quality of the CO2 stream. 

Proposed Financial Responsibility and Long-Term Care Requirements

• There is no language in the proposed regulation that covers compensation to homeowners for the 

degradation or loss of a water supply. 
U.S. Environmental Protection Agency - 6 - November 17, 2008 

• EPA should consider how Class VI wells and associated GS projects could impact the ownership 

of mineral rights in formations that are penetrated en route to the CO2 storage reservoir. Some 

suggestions include a mechanism to require disclosure of mineral rights that may be impacted by 

a sequestration project and how such ownership issues will be resolved. 

• If phased corrective action (plugging of existing penetrations) is to be approved, then the 

operator must post a 100 percent performance bond with the permitting agency before the permit 

is issued. The performance bond is to be in the amount necessary for the permitting agency to 

immediately complete the corrective action should the owner/operator fail to timely do so. 

Primacy for Class VI Wells

• There are no statutory limitations to EPA granting primacy to states for individual classes of 

underground injection wells; however, EPA typically refuses to do so by policy. Pennsylvania 

requests that EPA allow separable primacy for the proposed Class VI UIC well program, to 

secure that option. Resources to conduct the program continue to be the issue for any state 

considering primacy of the UIC program. Federal appropriations have been stagnant for over a 

decade at $10 million for the national program. Pennsylvania is concerned that EPA may not be 

able to secure the funding necessary to develop a robust Class VI well program that includes onthe-ground resources for non-primacy states. 

• Adequate resources must be made available to effectively develop and implement a program for 

this added category of UIC well that is this significantly different from other UIC well types. 

Proposed Duration of Class VI Injection Permit

• Permit renewal or review requirements should be added to the proposed rulemaking. The permit 

renewal or review process allows for extra permit transparency and regulatory authority to 

monitor and safeguard the operation. Pennsylvania recommends permit renewal or review every 

10 years. 

Target Geologic Formations for Geologic Sequestration of CO2

• EPA states in their documents (examples: pages 43502 to 43503 and 43512) that there are coal 

formations too deep to ever be mined. This is not true in Pennsylvania. All coal formations in 

Pennsylvania are at depths that are technologically capable of being mined. Economics will 

dictate whether or not these deeper coal formations will be mined.

• DEP and DCNR agree that EPA should preclude the injection of CO2 for long-term storage into 

coal seams where they are above the lowermost USDW. 

• There are safety issues associated with injecting CO2 below existing coal reserves. Uplifting 

pressure effects from injection below coal seams, or within deeper coal formations, may rupture 

flooded abandoned mines situated above active coal mines and will also drive coal bed methane 

upward into overlying active mines. There is also the safety issue of having an injection well(s) 

penetrate through coal before it is mined, which could be encountered during mining with 
U.S. Environmental Protection Agency - 7 - November 17, 2008 

devastating effects, both from injected CO2 release and from sparks from mining equipment 

encountering drill casing, and igniting coal bed methane. Pennsylvania regulates against this 

occurrence, with respect to oil and gas wells drilled through unmined coal formations, by the 

issuance of a pillar permit. The interaction of coal mines and wells is a major safety concern 

addressed by PA Chapter 78 Oil & Gas Wells. This regulation states that no permit will be 

issued for a well at a location that would, in the opinion of DEP, endanger the safety of persons 

working in a coal mine. Pennsylvania regulations do not address coal mine safety issues related 

to water wells or underground injection wells. 

• In drilling through an unmined coal formation resource or gas or oil reservoir formation, what 

area and distances from the injection drill path are considered safe for development? In 

Pennsylvania, when oil and gas wells are developed through a coal formation resource, a pillar 

permit is obtained which defines the area of safety within the undeveloped resource formation 

surrounding the drill path. 

How Would This Proposal Affect Existing Injection Wells Under the UIC Program?

• DEP and DCNR are concerned about the upgrading requirements necessary to grandfather 

existing EOR wells into the Class VI program. Historically, grandfathered installations such as 

wells have not been constructed to current standards and may not have adequate materials to 

meet the new requirements for injection. The standard of proof to demonstrate that an old well is 

adequate to be “grandfathered” should be high. The risk of needing remediation outweighs the 

inconvenience of upgrading an existing injection well. 

Definition of Carbon Dioxide Stream

• EPA should specify a CO2 purity requirement to prevent the inclusion of contaminants (example: 

hydrogen sulfide, sulfurous and nitrous oxides), the inclusion of which would not classify the 

CO2 stream as a hazardous waste/substance but could potentially endanger USDW and/or 

enhance corrosiveness. DEP understands that this subpart does not apply to a CO2 stream that 

meets the definition of a hazardous waste under 40 CFR Part 261.

Additional Issues

• Fluids could be brought to the surface during the drilling, completion and operation of the Class 

VI well. In the event formational fluids are brought to the surface during the sequestration 

process, appropriate measures must be taken. The regulation should address the issue of these 

fluids. 

• DEP believes that the CO2 for geologic sequestration is a residual waste if it does not otherwise 

qualify as a hazardous waste. Pennsylvania’s Solid Waste Management Act and residual waste 

regulations define disposal to include the injection of a residual waste and require a permit for 

disposal. 
U.S. Environmental Protection Agency - 8 - November 17, 2008 

 In conclusion, the Commonwealth of Pennsylvania maintains that this proposed rule represents a 

good initial effort to address issues related to the protection of USDW, while allowing for the potential 

development of carbon capture and storage. Pennsylvania is interested in participating in the process of 

addressing the questions, comments and concerns identified in this document. DEP and DCNR 

appreciate the opportunity to comment on this proposed regulation and look forward to assisting the 

EPA in concentrating on some of the remaining issues. 

 Should you have any questions or require additional information, please feel free to contact 

Christina Simeone, Executive Policy Specialist, Department of Environmental Protection, RCSOB, 

400 Market Street, 16th Floor, Harrisburg, PA 17101, 717-783-6395. 

Sincerely, Sincerely, 

John Hanger Michael DiBerardinis 

Acting Secretary Secretary 

Department of Environmental Protection Department of Conservation 

 and Natural Resources 
Letter ID: 0130 

Commenter: John Hanger 

Organization: Pennsylvania Dept. of Env. Protection 

Letter ID: 0130 Comment ID: 21499 Letter Lines: 23 to 93 

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

Comment: The Commonwealth of Pennsylvania’s Department of Environmental Protection 

(DEP) 

and Department of Conservation and Natural Resources (DCNR) are pleased to 

provide comments on the U.S. Environmental Protection Agency’s (EPA) proposed 

rule, "Federal Requirements Under the Underground Injection Control (UIC) 

Program for Carbon Dioxide (CO2) Geologic Sequestration (GS) Wells," published 

for comment on July 25, 2008, at 73 Federal Register 43492. 

Section 27 (relating to natural resources and the public estate) of the 

Pennsylvania Constitution declares that, "The people have a right to clean air, 

pure water, and to the preservation of the natural, scenic, historic, and 

esthetic values of the environment. Pennsylvania’s public natural resources are 

the common property of all the people, including generations yet to come. As 

trustee of these resources, the Commonwealth shall conserve and maintain them 

for the benefit of all the people." 

Geologic sequestration of CO2 would have to be conducted in a manner that 

complied with the laws and regulations of the Commonwealth. Although 

Pennsylvania does not have specific groundwater protection statutes, the Clean 

Streams Law provides the legal framework for managing the groundwater quality in 

the waters of the Commonwealth. The Pennsylvania Clean Streams Law, Act of 

1937, P.L. 1987, as amended in 1989, provides for preservation and improvement 

of the waters of the Commonwealth for the protection of public health, animal 

and aquatic life, and/or industrial consumption, and recreation. The Act states 

that "the waters of the Commonwealth shall be construed to include any and all 

rivers, streams, creeks, rivulets, impoundments, ditches, and other bodies or 

channels of conveyance of surface and underground (emphasis added) water, or 

parts thereof, whether natural or artificial, within or on the boundaries of the 

Commonwealth." Through the Clean Streams Law and specific program regulations, 

the goals and standards are integrated with all other state water quality and 

environmental goals. Specifically, 35 PA Code chapter 91.51 and chapter 91.52 

prohibit disposal of wastes underground by means that pose a threat to 

underground sources of drinking water. 

Act 70 of 2008, the Pennsylvania Climate Change Act, requires DEP to establish a 

permanent climate change advisory committee, designate voluntary emissions and 

offset registries, establish annual greenhouse gas inventories, develop an 

1
impacts assessment that identifies both scientific and economic impacts to 

Pennsylvania from climate change, and create a climate change mitigation action 

plan. The inventories, impacts assessment, and climate change action plan are 

to be presented to the General Assembly and Governor, and are to be updated 

every three years. Currently, DEP is working with the climate change advisory 

committee to comply with Act 70. 

Act 129 of 2008, amending the Title 66 (Public Utilities) of the Pennsylvania 

Consolidated Statues, requires DCNR to conduct studies of carbon capture and 

sequestration, and present its findings to the Governor and the General 

Assembly by mid-to-late 2009. The studies will include: 

(1) Identification of suitable geological formations for the location of a CO2 

sequestration network (due May 1, 2009); and 

(2) An independent assessment (due November 1, 2009) of the following: 

a) Costs to establish, operate, and maintain a CO2 sequestration network; 

b) Safety and potential risk to individuals, property, and the environment 

associated with the geological sequestration of CO2; 

c) Existing federal and state regulatory standards for the storage of CO2; 

d) Factors contained in the U.S. EPA’s vulnerability evaluation framework for 

geologic sequestration of CO2; 

e) Different types of insurance, bonds, other instruments and recommended levels 

of insurance which should be carried by an operator of a state network during 

construction and operation, and availability of commercial insurance; 

f) Models for the establishment of a Commonwealth fund to provide protection against risk. 

Following review of the above, Act 129 authorizes DCNR to conduct a pilot 

project to determine the viability of establishing a network in Pennsylvania 

that facilitates carbon capture, pipeline transmission, and geologic 

sequestration. 

The government of the Commonwealth of Pennsylvania is committed to preserving 

the natural resources and public estate afforded to the people of Pennsylvania. 

Individual Response: EPA recognizes the complexity and importance of states' approaches to 

managing GS and is aware that states are currently in various stages of developing statutory 

frameworks, regulations, workgroups, 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. 

2
Throughout the regulatory development process for the Class VI regulation, EPA monitored 

states' regulatory and legislative development efforts and approaches. In EPA's August 31, 2009, 

Notice of Data Availability (NODA) and Request for Comment, the Agency described its 

ongoing monitoring of states' regulatory efforts and approaches and how the Agency is 

considering this information as it develops guidance on the primacy application and approval 

process for Class VI wells. Information about these state activities may be found in the docket 

for the GS rule. 

Letter ID: 0130 Comment ID: 21500 Letter Lines: 94 to 102 

Comment Code: 1610 1.3.1 Risks to USDWs 

Comment: Both DEP and DCNR are interested in the greenhouse gas reduction opportunities 

that responsible carbon capture and storage may present. However, these 

opportunities should be approached with a clear understanding of the potential 

risks and must only be pursued with the best tools-in-hand to mitigate such 

risks. The DEP and DCNR believe that EPA’s proposed rule represents a solid 

effort to categorize and prevent some of the potential risks to underground 

sources of drinking water (USDW) that are associated with carbon capture and 

storage. The DEP and DCNR appreciate the opportunity to comment on this 

proposed rule. 

Individual Response: EPA acknowledges the commenter’s support and agrees that injecting 

large volumes of CO2 for GS poses unique challenges that, if not properly managed, could 

endanger drinking water sources and have other adverse impacts. However, the final, tailored, 

Class VI requirements address the large volumes of CO2 injected, its buoyancy, potential 

corrosivity in the presence of water, and potential impurities in the CO2 stream. In addition, EPA 

expects the tailored permitting, siting, construction, operation, monitoring, and post-injection site 

care requirements in the GS rule to prevent leakage from injection formations and protect 

USDWs. 

Letter ID: 0130 Comment ID: 21501 Letter Lines: 104 to 132 

Comment Code: 3150 2.1.5 Comments on required permit information (40 CFR 146.82) 

Comment: Proposed Class VI Permit Requirements 

-The permit applicant (owner/operator) for a proposed UIC Class VI well must 

demonstrate in the permit application that he owns the right to inject the CO2 

into the property and that his ownership extends to the entire area to which the 

CO2 may migrate. 

-Section 146.82 sets forth the information which the owner or operator must 

submit 

3
"(b) A map showing the injection well(s) for which a permit is sought 

and the applicable area of review. Within the area of review, the map must show... 

Only information of public record is required (emphasis added) to be included on 

this map;...." 

While it may be prudent to show only public information, it is also easy to 

avoid the aggravation of a diligent search by requiring that only public 

information is shown. This should not relieve the permittee from sharing any 

confidential information about the area, the subsurface conditions, the 

potential adjoining landuse, etc. Regulations should require full and complete 

disclosure of all information known, even if a confidential submittal is 

required. 

-It is possible that the owner/operator would be required to obtain information 

from neighboring non-owners in order to meet the requirements identified in the 

permit requirement and or area of review sections. EPA should identify the means 

by which Class VI owners/operators can obtain this information. This point is 

especially relevant to the inclusion of ‘buffer zones’ (see comments on the Area 

of Review) and the need to obtain site-specific information about these buffers. 

Individual Response: EPA clarifies that land and pore space ownership issues are outside the 

scope of the GS regulation and disagrees that it is necessary that the owner or operator of a GS 

site own the entire area to which the CO2 may migrate. EPA does believe, however, that it is 

important that the owner or operator have surface access to wells that require corrective action 

and for all necessary testing and monitoring during the life of the project. For this reason, the GS 

rule requires owners or operators to demonstrate that they will have access for these activities in 

the AoR and corrective action plan at §146.84(b) and testing and monitoring plan (§146.90). 

EPA acknowledges that information beyond publically available data may be needed to 

accurately assess the suitability of a site for GS. EPA believes that a determination about whether 

or what information may be necessary (for a specific GS project) is outside of the public record 

will be site-specific and based on knowledge of the site, data availability, and data quality. The 

Director has the discretion to require the owner or operator to supplement publically available 

data if there is reason to believe that the incompleteness of available information could 

compromise USDW protection from endangerment. 

In response to the comment suggesting that some of the required information may be available 

from neighboring land owners, EPA replies that if relevant information about the site exists (e.g., 

from earlier geologic studies of the area) and is available and the owner of that information is 

willing to share it, the Director may, at his/her discretion, allow its use in the site characterization 

for the GS project. 

Letter ID: 0130 Comment ID: 21502 Letter Lines: 134 to 157 

Comment Code: 3110 2.1.1 Proposed siting requirements (i.e., injection/confining zones, 

4
trapping mechanism) 

Comment: Proposed Geologic Siting Requirements 

-The proposed regulations should better express the need for characterizing the 

number, location, and depth of "underground sources of drinking water." 

Specifically, Pennsylvania recommends the addition of a subsection under 

"Geologic Siting Requirements" that calls for a hydrogeologic characterization 

of USDWs in the area of review. Although a number of technical requirements for 

such a characterization are presented in the Technical Support Document, 

"Geologic CO2 Sequestration Technology and Cost Analysis," such visibility is 

not present in the proposed rule itself. The depth and capacity of the regional 

groundwater system should be established in this characterization, along with 

other required details described in the Technical Support Documents. 

Groundwater flow directions and approximate water budgets to estimate deep 

components of flow will help to assess any injection well impacts to USDWs. 

Fracturing and faulting in context with the regional groundwater system should 

be a part of the hydrogeologic characterization. This would include an 

uncertainty analysis of current knowledge for the area. 

Also, consideration should be given for a recommendation of scales for maps and 

cross sections. Scales should be sufficient to provide enough detail for the 

"detailed geologic assessment." 

-The definition and criteria to ‘show or demonstrate secondary containment of 

the reservoir’ does not make sense for PA geology. EPA should allow for 

demonstration approaches that are flexible to regional geology. 

Individual Response: EPA is developing guidance on site characterization for GS projects to 

assist owners or operators and Directors in evaluating permit requirements and applications 

under §146.82. The guidance provides recommendations regarding characterizing the regional 

geology and hydrogeology of a proposed GS site as well as performing the necessary 

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

expects that this guidance will assist permit writers in evaluating this information. The guidance 

can be found on EPA’s website at 

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

Letter ID: 0130 Comment ID: 21503 Letter Lines: 159 to 171 

Comment Code: 3200 2.2 Proposed Area of Review and Corrective Action Requirements (40 

CFR 146.84) 

Comment: Proposed Area of Review and Corrective Action Requirements 

-PA needs to be assured that the designated "Area of Review" is sufficient and 

inclusive to provide for sound analysis of the impacts and control of potential 

environmental impacts to groundwater, water supplies, and surface water. State 

5
complications may arise from property and mineral rights related to permitting 

and operations of the proposed Class VI regulations based on this definition and 

its application. 

-Area of Review should include a "buffer zone" surrounding the Area of Review 

boundary that is adequate to address risk of improper assessment. The size of 

the boundary should be left to the applicant but should be subject to the 

Director’s approval. 

Individual Response: EPA agrees that the unique aspects of GS merit the use of sophisticated 

computational modeling for delineation of the AoR, based on site-specific features and geology, 

including the presence of faults, fractures, and artificial penetrations to ensure protection of 

USDWs. EPA believes that computational modeling of the AoR prior to injection will provide 

the best obtainable estimates of the extent of the CO2 plume over several years of active 

injection. EPA has strengthened the minimum frequency for the AoR reevaluation from ten years 

to 5 years (146.84(e)). EPA believes that this revised frequency addresses commenters' concerns 

about the inherent uncertainties in modeling CO2 movement, the emerging nature of GS 

technology, risk-based targeting of monitoring activities, and the unique nature of CO2 GS. 

EPA disagrees that incorporating a buffer zone into the definition of the AoR is necessary, 

because EPA believes that the AoR definition incorporates all areas that may be affected by the 

injection activity, and the iterative AoR reevaluation process required at 146.84(e) further 

accounts for uncertainty in the original modeling. The Agency has carefully considered all 

comments on the AoR definition at 146.84(a) and modified it to read as follows: The region 

surrounding the geologic sequestration project where USDWs may be endangered by the 

injection activity. The area of review is delineated using computational modeling that accounts 

for the physical and chemical properties of all phases of the injected CO2 stream and is based on 

available site characterization, monitoring, and operational data. 

Letter ID: 0130 Comment ID: 21504 Letter Lines: 173 to 178 

Comment Code: 3330 2.2.1.3 Applicability /adequacy of computational models (seeking 

comment) 

Comment: -The proposed rule discusses multiphase modeling and considers them appropriate 

for hydraulically connected formations being used by different operators. Where 

there are multiple operators injecting into a formation that is hydraulically 

connected, rules should require an evaluation of the chemical reaction of the 

different injections, unless they are chemically the same, as well as their 

interaction with native fluids. 

Individual Response: EPA agrees that the impacts of multiple operators injecting into 

hydraulically connected formations should be accounted for in the AoR modeling. EPA adds that 

the owner or operator must demonstrate in the proposed AoR and corrective action plan to the 

satisfaction of the Director that the modeled AoR will be based on detailed site-specific geologic 

data collected during the site characterization process including consideration of existing 

6
conditions (e.g., current injection activities). EPA anticipates that, where multiple operators are 

involved, the Director would not approve modeling that does not account for changes that may 

result from all injection operations in a formation or a series of hydraulically connected 

formations. EPA is developing guidance on AoR and corrective action at GS Class VI sites to 

assist owners or operators and Directors in evaluating requirements and proposed AoR and 

corrective action plans under 146.84. The guidance describes EPA's recommended approaches 

for the data to be considered in an initial AoR delineation, how to apply computational modeling 

to delineate the AoR, performing corrective action at GS sites, and, when appropriate, 

completing AoR reevaluations. The guidance will be available on EPA's web site, at 

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

Letter ID: 0130 Comment ID: 21505 Letter Lines: 180 to 183 

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

Comment: -Proprietary models should not be acceptable for use because of the complex 

nature of the activity and the many unknowns. Through a transparent process, 

EPA should maintain minimum modeling standards and assumptions required for 

approval. 

Individual Response: EPA disagrees that the use of proprietary models should be disallowed. 

EPA acknowledges that several proprietary models are currently, successfully used by 

petroleum-reservoir engineering professionals as well as in peer-reviewed studies to model CO2 

sequestration. 

EPA does not believe that the Agency should develop a standards and assumptions for modeling 

the AoR for GS sites. Instead, EPA believes that operators should have the flexibility to select 

the most appropriate models for the conditions at the GS site and based on the types and amount 

of data available given the wide range of site-specific conditions present at GS sites. EPA is 

developing guidance on AoR and corrective action at GS Class VI sites to assist owners or 

operators and Directors in evaluating requirements and proposed AoR and corrective action 

plans under §146.84. The guidance describes EPA's recommended approaches for the data to be 

considered in an initial AoR delineation, how to apply computational modeling to delineate the 

AoR, performing corrective action at GS sites, and, when appropriate, completing AoR 

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

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

EPA adds that its Confidential Business Information requirements at 40 CFR 144.5 will apply to 

the use of proprietary models. 

To ensure that all predictive models used for AoR calculations are meeting the Agency's 

expectations, 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. 

7
Letter ID: 0130 Comment ID: 21506 Letter Lines: 185 to 192 

Comment Code: 3660 2.2.4.2 Comments opposed to allowing phased corrective action 

Comment: -The rule proposes phased corrective action (plugging of existing penetrations) 

after injection begins, but the corrective action is to occur in advance of the 

CO2 plume. The rule should require all corrective action to occur before 

injection begins, or, if phased corrective action is to be approved, then the 

operator must post a 100 percent performance bond with the permitting agency 

before the permit is issued. The performance bond is to be in the amount 

necessary for the permitting agency to immediately complete the corrective 

action should the owner/operator fail to do so in a timely manner. 

Individual Response: EPA disagrees that phased corrective action is inappropriate for GS 

projects, and retains this provision in the final GS regulation. EPA acknowledges the concern 

regarding the uncertainty in AoR modeling, and notes that addressing this is the intent of the 

AoR reevaluation process. EPA adds that the final rule includes a requirement that the AoR be 

reevaluated every 5 years or when monitoring or operational conditions warrant a reevaluation as 

identified at §146.84(b)(2)(ii). 

Allowing phased corrective action is at the discretion of the Director. Any state, in developing a 

primacy package that is concerned that phased corrective action cannot be safely implemented 

based on the geologic or other conditions can prohibit Director's discretion to allow phased 

corrective action. 

EPA clarifies that owners or operators must also demonstrate and maintain financial 

responsibility for all corrective action, as specified in §146.85, whether it is performed prior to 

injection or phased. 

Letter ID: 0130 Comment ID: 21507 Letter Lines: 194 to 198 

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

Comment: Proposed Injection Well Operating Requirements 

-Appropriate deed restrictions and surface controls should be required to be 

implemented by the owner/operator to prevent another person from compromising 

the integrity of the confinement zone. 

Individual Response: EPA clarifies that issues related to deed restrictions and surface controls 

are outside the scope of the GS rulemaking. However, EPA agrees that the impacts of multiple 

operators injecting into hydraulically connected formations should be accounted for by the 

Director when determining whether to approve a Class VI permit application. EPA adds that, as 

part of the AoR evaluation process required at §146.84, the operator must demonstrate, in the 

8
proposed AoR and corrective action plan, to the satisfaction of the Director that the modeled 

AoR will be based on detailed geologic data collected on the site and includes consideration of 

existing conditions. EPA anticipates that, where multiple operators are involved, the Director 

would not approve modeling that did not account for the geochemical or pressure changes, 

including interactions with native fluids that may result from all injections into a formation or a 

series of hydraulically connected formations. 

Letter ID: 0130 Comment ID: 21508 Letter Lines: 207 to 226 

Comment Code: 1220 1.1.1.1 Terminology and definitions 

Comment Code: 4543 2.5.2.1 MIT procedures and methods for GS (seeking comment) 

Comment: Proposed Mechanical Integrity Testing Requirements 

-"Section 146.89 Mechanical integrity. (a) A Class VI well has mechanical 

integrity if: 

(1) There is no significant leak in the casing, tubing or packer; and (2) 

There is no significant fluid movement into a USDW through channels adjacent to 

the injection well bore. 

(b) To evaluate the absence of significant leaks under paragraph (a)(1) of 

this section, owners or operators must...." 

There is no definition of "significant" in the document. A definition should be 

included that explains how the term will be defined, such as some measurement 

around a mean, a variance interval, etc. Too often the term is used without an 

understanding of its technical meaning. This will also help the permittee to 

understand what is expectated. 

-‘De minimus’ CO2 leakage values should be determined and defined, as well as 

the acceptable measurement methodology and verification practices. 

Individual Response: A properly designed and operated well should have no leakage in the 

casing, tubing, or packer and no fluid movement into a USDW through channels adjacent to the 

wellbore. While the intent of MITs is to detect these types of problems as early as possible, the 

goal of the well design and construction requirements at §146.86 is the complete absence of such 

problems. EPA clarifies that the purpose of the "significant leakage" language in this narrow 

context is simply to avoid triggering corrective actions for essentially de minimis situations. 

Determining whether a MIT result should trigger follow-up action is necessarily a case and sitespecific situation; as a result, EPA does not believe it is appropriate to define the term 

"significant leakage" in the context of MITs. In addition, EPA has not defined this term for 

purposes of other injection well classes and this has not been shown to hinder permitting 

authorities' and owners or operators' ability to assess whether injection wells have adequate 

mechanical integrity. EPA believes that this approach allows states flexibility, will not interfere 

with the implementation of existing UIC programs, and maintains protection of USDWs from 

9
endangerment. 

In keeping with its adaptive rulemaking approach, the Agency plans to collect and review data 

every six years on early GS projects, including MIT data, 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: 0130 Comment ID: 21509 Letter Lines: 228 to 232 

Comment Code: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 

CFR 146.90) 

Comment: Proposed Plume and Pressure Front Monitoring Requirements 

-EPA should specifically identify (by technology) what type of monitoring would 

be necessary and applicable to verify containment of the CO2 and any failures 

away from the injection wells themselves. 

Individual Response: EPA does not believe that prescribing specific technologies to be used in 

all cases for GS would be appropriate given the variability in sites. Rather EPA is developing 

guidance on testing and monitoring to assist owners or operators and Directors in evaluating 

requirements under §146.90, including proposed monitoring plans. The guidance describes 

available technologies and recommended approaches for implementing a testing and monitoring 

plan, including pre-operational geophysical logging and testing of injection wells, MITs, 

injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume 

and pressure front, and soil gas and surface air monitoring which may be required by the UIC 

Director for specific GS projects. The guidance can be found on EPA’s website at 

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm. In addition, in January 2009, 

DOE published a best practices manual entitled "Monitoring, Verification, and Accounting of 

CO2 Stored in Deep Geologic Formations" (DOE/NETL-311/081508); this manual is included in 

the docket for the final GS rule. 

Letter ID: 0130 Comment ID: 21510 Letter Lines: 234 to 238 

Comment Code: 4640 2.6.4 Pressure fall-off testing (seeking comment) 

Comment: -Depending on the geology surrounding the containment formation, it is possible 

that the CO2 could be absorbed/adsorbed by some of the surrounding formations. 

This could cause a drop in pressure not directly associated with leakage. EPA 

should determine or allow for a maximum allowable pressure drop, or correction 

value, dependent on the appropriate surrounding geology. 

Individual Response: EPA believes that pressure fall-off testing is necessary for GS wells. 

10
Pressure fall-off tests are designed to verify that modeled projections of reservoir pressure 

decline agree with measured pressure decline profiles. These tests can be useful in AoR 

calculations and reevaluations and may also indicate mischaracterization of site geology and the 

presence of leakage pathways. EPA therefore believes that pressure fall-off testing is necessary 

every five years at a minimum, and the final GS regulation includes this requirement at 

§146.90(f). Pressure fall-off tests may be conducted in conjunction with other well performance 

tests (i.e., mechanical integrity testing) to ensure safe and effective operations. 

EPA is developing guidance on testing and monitoring at GS sites, which will address pressure 

fall-off testing. The guidance also describes available technologies and recommended 

approaches for implementing a testing and monitoring plan, including pre-operational 

geophysical logging and testing of injection wells, MITs, injection well testing during operation, 

groundwater quality monitoring, tracking the CO2 plume and pressure front, and soil gas and 

surface air monitoring which may be required by the UIC Director for specific GS projects. The 

guidance can be found on EPA’s website at 

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

Letter ID: 0130 Comment ID: 21511 Letter Lines: 240 to 242 

Comment Code: 4650 2.6.5 CO2 plume and pressure front tracking (seeking comment) 

Comment: -EPA should identify specific technologies or processes that will enable 

operators or owners to verify that the CO2 is moving the way in which the models 

indicated. 

Individual Response: EPA does not believe that prescribing specific technologies to be used in 

all cases for GS would be appropriate given the variability in sites. Rather, EPA is developing 

guidance on testing and monitoring to assist owners or operators and Directors in evaluating 

requirements under §146.90, including proposed monitoring plans. The guidance describes 

available technologies and recommended approaches for implementing a testing and monitoring 

plan, including pre-operational geophysical logging and testing of injection wells, MITs, 

injection well testing during operation, groundwater quality monitoring, tracking the CO2 plume 

and pressure front, and soil gas and surface air monitoring which may be required by the UIC 

Director for specific GS projects. The guidance can be found on EPA’s website at 

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm. In addition, in January 2009, 

DOE published a best practices manual entitled "Monitoring, Verification, and Accounting of 

CO2 Stored in Deep Geologic Formations" (DOE/NETL-311/081508); this manual is included in 

the docket for the final GS rule. 

Letter ID: 0130 Comment ID: 21512 Letter Lines: 244 to 244 

Comment Code: 5800 2.13 Comments on emergency and remedial response (40 CFR 146.94) 

Comment: -EPA should identify existing methods for remediation of a rogue CO2 plume. 

11
Individual Response: EPA clarifies that determining appropriate remedial actions and 

mitigation technologies that may be employed at a GS site is site- and event-specific and will 

depend on a variety of factors, including the nature of any movement of CO2 or other fluids, the 

presence of USDWs, and what, if any, impacts may have resulted. EPA is developing guidance 

on the development and implementation of emergency and remedial response plans for GS sites. 

EPA clarifies that, if owners or operators obtain evidence that USDWs may be endangered or 

that leakage is occurring, owners or operators must cease injection, take all steps reasonably 

necessary to identify and characterize any release, notify the Director, and implement the 

approved emergency and remedial response plan (§146.94(b)). 

Letter ID: 0130 Comment ID: 21513 Letter Lines: 246 to 265 

Comment Code: 4720 2.7.2 Operational recordkeeping and reporting 

Comment: Proposed Recordkeeping and Reporting Requirements 

-The chemistry of the gas stream will be affected by the fuel source and the 

operating conditions of the capture and purification systems. These data, while 

not the responsibility of the operator, can have significant impacts on the gas 

constituents. Semi-annual reports will not be timely in identifying these 

impacts. The operator should require reports from the gas source, which can be 

forwarded to EPA as part of the semi-annual report, or as an additional 

submittal between the semi-annual reports. Once parameters of operations are 

known, the reports could be waived or modified. A specific example of a 

potential concern: Power Plant A receives a modification to its air permit from 

a non-primacy state. The modification allows the burning of petcoke, which 

commonly has a high vanadium content. Vanadium oxides can form on operating 

surfaces, affecting capture system efficiencies, or possible modifying down-hole 

behavior. This type of change could greatly affect the overall system. 

-Also, operating performance of the gas suppliers’ systems should be monitored. 

Changes in characteristics such as pressure drop, filter cloth efficiencies, 

increases or changes in dilution air, etc., can affect the quality of the CO2 

stream. 

Individual Response: EPA is retaining the semi-annual reporting requirement in the final rule at 

§146.91(a) in order to ensure that permitting authorities can maintain proper oversight and track 

compliance of GS projects, particularly in the early stages of rule implementation and 

deployment of GS technologies. The Agency also clarifies that permitting authorities may 

choose to require more frequent reporting, at the discretion of the Director. 

EPA cannot reply specifically as to whether any change to the CO2 stream or the fuel source 

would warrant a change in the permit. However, it is possible that a permit may have to be 

modified for these reasons. Section 144.39(a) identifies causes for modification of permits that 

would invoke the public notification procedures at Part 124, including: alterations or additions to 

the facility; availability of additional information; new regulations; and compliance schedule 

12
modifications. EPA added text to §144.39(a)(5) that permit modifications would be required if 

the Director determines that a modification is necessary based on an AoR reevaluation, 

amendments to any of the project plans, or a review of the testing and monitoring results. 

If the source of the injectate changes, the Director must evaluate whether this change warrants a 

modification of the permit or is a minor modification based on site-specific information about the 

injection project, including geologic information about the injection and confining zones, 

formation fluids, and the well's construction. If the injectate from the new source were within the 

capacity of the facility, this would be considered a minor modification per §144.41(h); otherwise 

the Director must initiate a public process regarding the change in the permit. 

Please see the final rule and the discussion of testing and monitoring for GS projects in the 

preamble for additional information. 

Letter ID: 0130 Comment ID: 21514 Letter Lines: 267 to 282 

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

ownership 

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

CFR 146.85) 

Comment: Proposed Financial Responsibility and Long-Term Care Requirements 

-There is no language in the proposed regulation that covers compensation to 

homeowners for the degradation or loss of a water supply. 

-EPA should consider how Class VI wells and associated GS projects could impact 

the ownership of mineral rights in formations that are penetrated en route to 

the CO2 storage reservoir. Some suggestions include a mechanism to require 

disclosure of mineral rights that may be impacted by a sequestration project and 

how such ownership issues will be resolved. 

-If phased corrective action (plugging of existing penetrations) is to be 

approved, then the operator must post a 100 percent performance bond with the 

permitting agency before the permit is issued. The performance bond is to be in 

the amount necessary for the permitting agency to immediately complete the 

corrective action should the owner/operator fail to timely do so. 

Individual Response: EPA clarifies that the goal of the financial responsibility requirements is 

to ensure that financial resources are available to prevent endangerment of USDWs from 

improper plugging, remediation, and management of wells in the event that the owner or 

operator experiences financial difficulties. EPA would also like to highlight the emergency and 

remedial response plan required under the rule. This includes the cost to perform any necessary 

responses or remediation to address potential USDW endangerment. See the preamble to the 

final rule for more details on the emergency and remedial response requirements. 

13
EPA clarifies that pore space ownership and surface and subsurface property and mineral rights 

are outside the scope of the UIC GS rulemaking. EPA recognizes that many of these issues are 

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

though state regulations. The purpose of the Class VI GS rule is to ensure that where GS 

technologies are deployed, GS is performed in a manner that protects USDWs from 

endangerment. 

EPA agrees with the comment on phased corrective action. The GS rule, at §146.85(c), requires 

the owner or operator to have a detailed written estimate, in current dollars, of the cost of: 

performing corrective action on wells in the AoR, plugging the injection well(s), PISC and site 

closure, and emergency and remedial response. A cost estimate must be prepared separately for 

each of these activities and be based on the costs to the owner or operator of hiring a third party 

(who is neither a parent nor a subsidiary of the owner or operator) to perform the activities. EPA 

clarifies that owners or operators will need to demonstrate and maintain financial responsibility 

for all corrective action at the time of Class VI well permitting, before the onset of injection 

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

financial responsibility. 

Letter ID: 0130 Comment ID: 21515 Letter Lines: 284 to 299 

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: Primacy for Class VI Wells 

-There are no statutory limitations to EPA granting primacy to states for 

individual classes of underground injection wells; however, EPA typically 

refuses to do so by policy. Pennsylvania requests that EPA allow separable 

primacy for the proposed Class VI UIC well program, to secure that option. 

Resources to conduct the program continue to be the issue for any state 

considering primacy of the UIC program. Federal appropriations have been 

stagnant for over a decade at $10 million for the national program. 

Pennsylvania is concerned that EPA may not be able to secure the funding 

necessary to develop a robust Class VI well program that includes on-the-ground 

resources for non-primacy states. 

-Adequate resources must be made available to effectively develop and implement 

a program for this added category of UIC well that is this significantly 

different from other UIC well types. 

Individual Response: EPA agrees 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. In the past, EPA has not accepted UIC primacy applications 

for individual well classes under Section 1422 of SDWA. In other words, if a State wanted 

primacy for Class I wells, the State would also need to accept responsibility for Class III, IV, and 

V wells. This policy has been in place since the initiation of the UIC Program in the early 1980s 

14
and was intended to encourage States to take full responsibility for UIC programs, avoid 

duplication of efforts, and provide for administrative efficiencies. 

However, 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 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. 

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) 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 to ensure that their GS programs integrate into 

national climate change priorities and protect USDWs from endangerment. 

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: 0130 Comment ID: 21516 Letter Lines: 301 to 306 

Comment Code: 5700 2.12 Comments on the proposed duration of Class VI permits (seeking 

comment) 

15
Comment: Proposed Duration of Class VI Injection Permit 

-Permit renewal or review requirements should be added to the proposed 

rulemaking. The permit renewal or review process allows for extra permit 

transparency and regulatory authority to monitor and safeguard the operation. 

Pennsylvania recommends permit renewal or review every 10 years. 

Individual Response: The final rule maintains the lifetime permit provision and clarifies that the 

permit extends through the post-injection site care period (144.36(a)). However, it also adds a 

requirement that the Director review each Class VI permit at least once every 5 years to 

determine whether it should be modified, revoked and reissued, terminated or a minor 

modification made as provided in §§144.39, 144.40, or 144.41. The Director’s review will be 

informed by the owners’ or operators’ iterative reevaluation of the project. Specifically, the final 

rule includes a requirement that the AoR be reevaluated at least every five years, and also 

requires owners or operators to review and update the AoR and corrective action plan, the testing 

and monitoring plan, and the emergency and remedial response plan throughout the life of the 

project (146.84(e), 146.90(j), and 146.94(d)). Owners or operators must review each plan and 

identify necessary amendments or demonstrate to the Director that no amendment is needed. In 

no case can reviews occur less often than once every five years. The iterative process and 

subsequent plan reevaluations ensure that time and resources are committed to the most critical 

aspects of the permit in preventing endangerment to USDWs. 

EPA adds that, as part of existing requirements at 40 CFR 144.39, the Director has the authority 

to revise the permit if project operations change or if the Director believes based on monitoring 

or operational data that the project may endanger USDWs. EPA has also added text to 

144.39(a)(5) requiring permit modifications if the Director determines that a modification is 

necessary based on an AoR reevaluation, amendments to any of the project plans, or a review of 

the testing and monitoring results. The Director may also choose to require minor permit 

modifications under 40 CFR 144.41 depending on the extent of the plan amendment. All permit 

modifications, except minor modifications under 40 CFR 144.41, require an opportunity for 

public comment on the portion of the permit that is being reopened pursuant to requirements 

under 40 CFR Part 124. 

The Agency plans to collect and review data on GS projects every six years 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: 0130 Comment ID: 21517 Letter Lines: 308 to 314 

Comment Code: 2160 1.6.3 Unmineable coal seams 

Comment: Target Geologic Formations for Geologic Sequestration of CO2 

-EPA states in their documents (examples: pages 43502 to 43503 and 43512) that 

there are coal formations too deep to ever be mined. This is not true in 

16
Pennsylvania. All coal formations in Pennsylvania are at depths that are 

technologically capable of being mined. Economics will dictate whether or not 

these deeper coal formations will be mined. 

Individual Response: EPA acknowledges the comment, and clarifies that the use of coal mines 

for anything other than GS is outside the scope of the GS rulemaking. 

Letter ID: 0130 Comment ID: 21518 Letter Lines: 316 to 341 

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

Comment: -DEP and DCNR agree that EPA should preclude the injection of CO2 for long-term 

storage into coal seams where they are above the lowermost USDW. 

-There are safety issues associated with injecting CO2 below existing coal 

reserves. Uplifting pressure effects from injection below coal seams, or within 

deeper coal formations, may rupture flooded abandoned mines situated above 

active coal mines and will also drive coal bed methane upward into overlying 

active mines. There is also the safety issue of having an injection well(s) 

penetrate through coal before it is mined, which could be encountered during 

mining with devastating effects, both from injected CO2 release and from sparks 

from mining equipment encountering drill casing, and igniting coal bed methane. 

Pennsylvania regulates against this occurrence, with respect to oil and gas 

wells drilled through unmined coal formations, by the issuance of a pillar 

permit. The interaction of coal mines and wells is a major safety concern 

addressed by PA Chapter 78 Oil & Gas Wells. This regulation states that no 

permit will be issued for a well at a location that would, in the opinion of 

DEP, endanger the safety of persons working in a coal mine. Pennsylvania 

regulations do not address coal mine safety issues related to water wells or 

underground injection wells. 

-In drilling through an unmined coal formation resource or gas or oil reservoir 

formation, what area and distances from the injection drill path are considered 

safe for development? In Pennsylvania, when oil and gas wells are developed 

through a coal formation resource, a pillar permit is obtained which defines the 

area of safety within the undeveloped resource formation surrounding the drill 

path. 

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 

17
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. 

EPA adds that all decisions regarding injection depth waivers are at the Director's discretion. If a 

Director believes that injection depth waivers are not appropriate for a specific site or for a 

category of formations within their state, the Director has the authority to not permit such 

injections. 

EPA is developing guidance on the injection depth waiver process. The guidance describes the 

recommended approach an owner or operator may follow when submitting a waiver application, 

processing waiver applications by the UIC and PWSS Program Directors, and additional 

processes that may apply to projects that have been issued waivers. This guidance will be 

available on EPA’s website at 

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

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: 0130 Comment ID: 21519 Letter Lines: 343 to 351 

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

Comment: How Would This Proposal Affect Existing Injection Wells Under the UIC Program? 

-DEP and DCNR are concerned about the upgrading requirements necessary to 

grandfather existing EOR wells into the Class VI program. Historically, 

grandfathered installations such as wells have not been constructed to current 

standards and may not have adequate materials to meet the new requirements for 

injection. The standard of proof to demonstrate that an old well is adequate to 

be “grandfathered” should be high. The risk of needing remediation outweighs 

the inconvenience of upgrading an existing injection well. 

Individual Response: EPA agrees that a cautious approach to grandfathering is appropriate, 

particularly given that the converted well will be used for a substantially different process, which 

involves increased reservoir pressures associated with large volumes of stored CO2 and 

corrosivity of CO2 in the presence of water. The final GS rule provides that the construction of 

these wells to be grandfathered (per 146.81(c)). EPA has included a requirement in the final GS 

rule that owners or operators seeking to convert existing wells for long term storage must 

demonstrate to the Director that the grandfathered wells were engineered and constructed 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 reuirements are 

18
grandfathered and that all other Class VI requirements (reporting, monitoring, mechnical 

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

Letter ID: 0130 Comment ID: 21520 Letter Lines: 353 to 360 

Comment Code: 1614 1.3.1.2 Impurities in captured CO2; purity standards for CO2 

Comment: Definition of Carbon Dioxide Stream 

-EPA should specify a CO2 purity requirement to prevent the inclusion of 

contaminants (example: hydrogen sulfide, sulfurous and nitrous oxides), the 

inclusion of which would not classify the CO2 stream as a hazardous 

waste/substance but could potentially endanger USDW and/or enhance 

corrosiveness. DEP understands that this subpart does not apply to a CO2 stream 

that meets the definition of a hazardous waste under 40 CFR Part 261. 

Individual Response: EPA understands that many CO2 streams may be relatively pure, and 

research indicates that the estimated amounts of impurities in a CO2 stream are likely to be low. 

However, these estimates are based on limited information, and uncertainties remain about the 

expected concentrations of impurities from the various types of CO2 streams. The concentrations 

of minor and trace elements in CO2 streams for GS projects are likely to vary by facility, coal 

composition, plant operating conditions, and pollution removal technologies. 

The GS rule does not set generic purity standards for CO2 injectate streams (e.g., a percent 

CO2). Instead, the GS rule addresses the quality and quantity of impurities by requiring owners 

or operators to submit information on the source of the CO2 and its physical and chemical 

properties. Specifically, the GS rule requires the owner or operator to submit data about the site, 

including an analysis of the chemical and physical characteristics of the CO2 stream, as required 

at §146.82(a)(7)(iv), and information on the compatibility of the CO2 stream with fluids in the 

injection zone and minerals in both the injection and the confining zones and the materials used 

to construct the well, per §146.82(c)(3). This information can help the Director determine the 

potential for geochemical reactions between the injectate (CO2) and the host geologic 

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

minerals. 

Since the GS rule, at §146.81(d), prohibits CO2 streams that meet the definition of a hazardous 

waste under 40 CFR part 261, injection of a CO2 stream that is determined to be a hazardous 

waste may only occur in a Class I hazardous waste injection well. 

Letter ID: 0130 Comment ID: 21521 Letter Lines: 362 to 367 

Comment Code: 1616 1.3.1.3 Fluid movement 

Comment: Additional Issues 

19
-Fluids could be brought to the surface during the drilling, completion and 

operation of the Class VI well. In the event formational fluids are brought to 

the surface during the sequestration process, appropriate measures must be 

taken. The regulation should address the issue of these fluids. 

Individual Response: EPA acknowledges that there are potential risks associated with GS 

including the potential that CO2 injection for GS could cause fluid movement, which can 

endanger USDWs. The purpose of the Class VI requirements is to minimize and mitigate 

potential/identified risks through proper site characterization, well construction, operation, 

monitoring, post-injection site care, and site closure. Suitable GS sites must have confining zones 

that are free of transmissive faults or fractures and are of sufficient areal extent and integrity to 

contain the injected CO2 stream and displaced formation fluids. The formations must allow 

injection at proposed maximum pressures and volumes without initiating or propagating 

fractures in the confining zone(s), as required at §146.83(a)(2). 

The GS rule requires owners or operators to submit extensive data about a proposed GS site to 

identify (and eliminate) sites with a potential for unacceptable fluid movement. Information to be 

submitted and evaluated at §146.82 includes data on the porosity, permeability, and other 

information regarding the suitability of the confining zone; the location of any known or 

suspected faults; subsurface geochemistry; and the location of, depth of, and other information 

regarding any perforations that may extend into the confining zone. EPA believes that this 

information, in conjunction with AoR modeling required at §146.84, will help identify the 

potential for brine migration as a result of pressure displacement. Based on this information, the 

Director and the owner or operator can identify ways to mitigate this risk prior to injection, or, if 

necessary, the Director can deny the permit application. During injection operations, operators 

must extensively monitor ground water quality and pressure changes to provide early detection 

of any unacceptable movement of fluids or impurities in the subsurface as specified in §146.90. 

In the event that fluid movement endangers a USDW, owners or operators must also develop and 

follow an emergency and remedial response plan to address any adverse effects associated with 

the GS operation as specified in §146.94 and maintain financial responsibility to address 

contamination as specified in §146.85. 

Letter ID: 0130 Comment ID: 21522 Letter Lines: 369 to 372 

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

Comment: -DEP believes that the CO2 for geologic sequestration is a residual waste if it 

does not otherwise qualify as a hazardous waste. Pennsylvania’s Solid Waste 

Management Act and residual waste regulations define disposal to include the 

injection of a residual waste and require a permit for disposal. 

Individual Response: EPA clarifies that the GS rule itself does not change the status of CO2 as 

a solid waste or hazardous waste under RCRA. Under the final GS rule, owners or operators will 

need to determine whether the CO2 stream is a hazardous waste under EPA’s RCRA regulations, 

and if so, any injection of the hazardous CO2 stream may only occur in a Class I hazardous 

waste injection well. 

20
Letter ID: 0130 Comment ID: 21523 Letter Lines: 374 to 381 

Comment Code: 1420 1.2.1.1 Support the GS rulemaking 

Comment: In conclusion, the Commonwealth of Pennsylvania maintains that this proposed 

rule represents a good initial effort to address issues related to the 

protection of USDW, while allowing for the potential development of carbon 

capture and storage. Pennsylvania is interested in participating in the process 

of addressing the questions, comments and concerns identified in this document. 

DEP and DCNR appreciate the opportunity to comment on this proposed regulation 

and look forward to assisting the EPA in concentrating on some of the remaining 

issues. 

Individual Response: EPA acknowledges the comment and 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 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 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: 0130 Comment ID: 25077 Letter Lines: 200 to 205 

Comment Code: 4600 2.6 Proposed Plume and Pressure Front Monitoring Requirements (40 

CFR 146.90) 

Comment: -Language is included in the proposed rule detailing how the injection well will 

be monitored during its operation, but there is no language included that 

regulates the monitoring of areas surrounding the injection well. There is also 

concern about how deep and how close to the capping (sealing) formation the 

surrounding monitoring wells and other wells should be allowed to approach the 

capping formation. 

Individual Response: EPA clarifies that the final GS regulation, at §146.90(g)(1), requires all 

21
22

GS project owners or operators to monitor for pressure changes in the injection zone. Specific 

monitoring locations will be identified by the owner and operator and approved by the Director 

in the monitoring and testing plan, but EPA expects that monitoring wells will be placed 

throughout the AoR. EPA believes that pressure monitoring in the injection zone is necessary to 

track the development and movement of the pressure front and CO2 plume and eliminates the 

need for monitoring in the locations mentioned by the commenter. 

Pressure monitoring within the injection zone is also necessary because any such monitoring 

above the confining zone would not detect movement of the pressure front unless a breach of the 

confining zone occurs. EPA believes that monitoring using wells in the injection zone (i.e., that 

penetrate the confining zone) can be safely performed if the wells are constructed to prevent flow 

between the injection zone and USDWs or other layers above the confining zone. Such 

construction technologies exist and have been used in the oil and gas industry for years. EPA 

believes that the benefits of monitoring in the injection formation outweigh the manageable risk 

of those monitoring wells serving as conduits for fluid movement. EPA is developing guidance 

on well construction that will include recommendations for monitoring well construction. The 

guidance will be available on EPA’s website at 

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

EPA adds that owners or operators may consider performing additional pressure monitoring in 

wells that are above the confining zone (e.g., in the same wells used to perform ground water 

quality monitoring required at §146.90(d)) to provide additional verification that no pressure 

changes are occurring above the confining zone due to CO2 leakage. Monitoring also identifies 

needed remedial actions, provides inputs for AoR reevaluation modeling, and targets additional 

geochemical and surface monitoring needs. Knowledge of the location of the CO2 plume and the 

associated pressure front will assure the public that GS projects are proceeding according to plan, 

provide sufficient information to the owner or operator and Director, or allow for appropriate 

actions to address any indication that USDWs may be endangered. 

EPA is developing guidance on testing and monitoring to assist owners or operators and 

Directors in evaluating requirements under §146.90, including proposed monitoring plans. The 

guidance describes available technologies and recommended approaches for implementing a 

testing and monitoring plan, including pre-operational geophysical logging and testing of 

injection wells, MITs, injection well testing during operation, groundwater quality monitoring, 

tracking the CO2 plume and pressure front, and soil gas and surface air monitoring, which may 

be required by the UIC Director for specific GS projects. The guidance can be found on EPA’s 

website at http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm. In addition, in 

January 2009, DOE published a best practices manual entitled "Monitoring, Verification, and 

Accounting of CO2 Stored in Deep Geologic Formations" (DOE/NETL-311/081508); this 

manual is included in the docket for the final GS rule.