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.
 

GROUP AGAINST SMOG AND POLLUTION COMMENTS ON THE 

ENVIRONMENTAL PROTECTION AGENCY PROPOSED FEDERAL 

REQUIREMENTS UNDER THE UIC PROGRAM FOR GEOLOGIC 

SEQUESTRATION OF CARBON DIOXIDE 

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

Prepared by Herbert Skolnick, Ph.D. 

September 30, 2008 

 The Group Against Smog and Pollution (GASP) has three primary concerns 

regarding the geologic sequestration of CO2: 

1. The potential for adverse chemical reaction of CO2 and its contaminants 

with the water/mineral environment of the host rock. 

2. The need for Class VI wells given the advantages of CO2 enhanced recovery 

methods in existing Class II wells. 

3. What agency will administer and oversee the program? At least five 

agencies could be involved: EPA, DOE, DOT, USGS, and BLM. 

Potential for Adverse Chemical Reactions:

The corrosive nature of carbon dioxide in the presence of water was noted several 

times during the work sessions conducted during the late-February CO2 sequestration 

meetings.1

 Chemical reactions between the injected carbon dioxide and the pore water in 

the host rock should be expected, resulting in solution and redeposition of host mineral 

material and loss of pore volume. 

For thirty years, the reviewer worked as a geologist for Gulf Oil studying and 

analyzing thousands of surface and subsurface samples of sandstones and quartzite rocks 

 

1

 U.S. ENVIRONMENTAL PROTECTION AGENCY, Proposed UIC Regulations for Geologic Sequestration of 

Carbon Dioxide, Feb. 26-27, 2008. 

GROUP AGAINST SMOG & POLLUTION, INC. Wightman School Community Building 

5604 Solway Street, Suite 204 

Pittsburgh, Pennsylvania 15217 

Phone: (412) 325-7382; Fax: (412) 325-7390 

Website: http://www.gasp-pgh.org
from different parts of the world. Siliceous overgrowths on the quartz grains making up 

these rocks were common and in some instances resulted in the total loss of pore volume. 

The overgrowths ranged from amorphous silica, various cherts, cryptocrystalline quartz 

to quartz deposited in crystalline continuity with the host grains.2

 Thus when the 

presence of silica is suspected in a CO2 stream,3 silica content should be determined prior 

to sequestration—particularly where storage in sandstone or quartzite formations is 

contemplated. 

The Need for Class VI Wells: 

In the 2005 Energy Policy Act, Congress gave the Department of Energy the 

mission to investigate the gathering, transportation and injection of CO2 into oil and gas 

fields to increase production.4

 On September 6, 2006, the DOE announced its own 

program with a dual purpose of storing CO2 and using the gas for enhanced oil recovery.5 

According to the DOE, only about 10 per cent of the oil contained in an oil field is 

produced initially. Further production is achieved by injecting steam and water into the 

reservoir rock to overcome the viscosity of the remaining oil and move it into the 

collection wells. The oil industry has also been injecting CO2 into oil-bearing reservoirs 

since 1972. It has proven to be the most efficient enhanced recovery method to date. A 

major drawback has been its high cost even considering the current cost of oil.6

 

The CO2 used early on was produced from naturally CO2-containing rocks. To 

mitigate the cost of the CO2, a number of current projects use CO2 collected from the flue 

gasses of industrial plants, including the construction of dedicated pipelines to transport 

the CO2 to oil fields for enhanced recovery operations (one such example is the line from 

the Dakota Gasification Plant in Beulah, North Dakota to the Weyburn oil field in 

Saskatchewan, Canada.) Ultimately with these additional technologies total production 

 

2

 Skolnick. H., The Quartzite Problem, JOUR. SED. PET. V.35, p.12-22 (1965), (The most extreme observed 

example was a core from Peru in which all of the pore volume was filled with the mineral pyrite) 

3

 For instance, CO2 derived from the combustion of coal may contain significant levels of silica due to the 

presence of fly ash in the waste stream. 

4

 42 U.S.C. 15910. 

5

 DOE - Fossil Energy Techline: A Two-For-One Solution 

http://fossil.energy.gov/news/techlines/2006/06050-DOE_Awards_EOR_Project.html 6

 DOE, 2008, Fossil Energy: DOE's Oil Recovery R&D Programs, 

http://fossil.energy.gov/programs/oilgas/eor/ 
can be increased to 30 to 60% of the original oil in place.7

 At the present time, given the 

current production of flue gas, there is enough storage space in existing depleted oil fields 

to sequester CO2 well into the next century.8

In contrast, the proposed Class VI wells will be newly drilled, and potential well 

sites will require extensive study to determine if the area’s geological characteristics are 

acceptable. Substantial savings of time and money would be realized if the EPA instead 

used the large number of Class II enhanced oil recovery/enhanced gas recovery wells that 

already exist. Oil and gas have been produced from some of these sites for many years, 

and the chemistry, reservoir characteristics, and geology of the sites have been 

extensively studied and understood. This is the class of wells that should be exploited 

first. 

A program with the dual mission of CO2 sequestration plus utilization of the gas 

in enhanced recovery of oil and gas has much more to offer in terms cost savings, time 

savings, and overall efficiency. Of equal significance is the increase in oil and gas 

production—particularly in light of concerns over US reliance on foreign oil and the 

present push for offshore drilling. The DOE estimates that given new CO2 technology 

existing oil fields can produce as much as an additional 500 thousand barrels per day by 

2012 and as much as 2 million barrels per day by 2020.9

Finally, given the lower costs of CO2 sequestration in existing oil fields and the 

attendant increased oil production, sequestration in existing oil fields is also more likely 

to provide storage site operators with the financial resources necessary to ensure proper 

site closure and post-closure care, and to meet long-term financial assurance 

requirements. 

Agency Administration and Oversight 

The costs and logistics of large scale CO2 sequestration are mindboggling. 

Participating utilities will have to retrofit in order to collect, clean, compress, and store 

CO2; pipelines and storage depots must be constructed; and fleets of tanker trucks will be 

required for transport. Given the critical environmental and energy problems we face and 

 

7 Id.

8

 Schrag, D., Preparing to Capture Carbon, SCIENCE, p812-813, Feb. 9, 2007. 9

 DOE supra note 6. 
the complexity of large scale CO2 sequestration infrastructure, the CO2 sequestration 

program needs special oversight to keep costs down, maintain efficiency, minimize 

political interventions, and keep inter-agency squabbles out of the mix. The roles of 

relevant government agencies, particularly EPA and DOE, must be clarified in order to 

keep administration as uncomplicated as possible and provide strong oversight. 

Conclusion 

Regardless of what specific form the CO2 sequestration program ultimately takes, 

at a minimum, the program must ensure that: 

1. the chemistry of the CO2 and its contaminants is ascertained prior to injection; 

2. the sequestered material’s behavior in the chemical, geological, and 

hydrological environment where it is stored is anticipated and carefully 

monitored; and 

3. steps must be taken to ensure that site operators have sufficient financial 

resources to cover post-closure care and any potential future liability. 
Letter ID: 0110 

Commenter: Herbert Skolnick, Ph.D. 

Organization: Group Against Smog and Pollution, Inc. (GASP) 

Letter ID: 0110 Comment ID: 22035 Letter Lines: 15 to 25 

Comment Code: 1320 1.1.3 General comments about GS 

Comment: The Group Against Smog and Pollution (GASP) has three primary concerns 

regarding the geologic sequestration of CO2: 

1. The potential for adverse chemical reaction of CO2 and its contaminants with 

the water/mineral environment of the host rock. 

2. The need for Class VI wells given the advantages of CO2 enhanced recovery 

methods in existing Class II wells. 

3. What agency will administer and oversee the program? At least five agencies 

could be involved: EPA, DOE, DOT, USGS, and BLM. 

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

including the potential that CO2 injection for GS may result in leaching of subsurface materials 

that could mobilize contaminants or compromise pore space, and therefore injectivity. The 

purpose of the Class VI requirements is to minimize and mitigate potential or identified risks 

through proper site characterization, well construction, operation, monitoring, post-injection site 

care, and site closure. To ensure USDW protection and mitigate risks, the GS regulation requires 

the owner or operator of a Class VI well to submit data about the site (during the site 

characterization process), including information on the porosity, permeability, mineralogy, and 

geochemistry of the injection and confining zones, along with information on the compatibility 

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

confining zones (§146.82). This data can help identify potential geochemical reactions that may 

occur between the injected CO2 and the host geologic formation. Identification of potential 

reactions prior to injection would address concerns that formation of carbonic acid could 

dissolve potential limestone creating karst features. 

Regarding EOR wells, EPA recognizes that the oil and gas industry has decades of experience 

injecting CO2 for the purpose of ER, and that sites used for ER may be suitable for GS and may 

be among the first GS sites. However, the Agency believes that the nature of CO2 injection for 

the primary purpose of long term storage poses different risks than injection for the primary 

purpose of ER, and therefore has developed new Class VI regulations to address these unique 

risks. For example, the volume of CO2 anticipated to be injected for long term storage is 

significantly greater than for ER operations. Reservoir pressure conditions will also be different, 

with Class VI injection operations involving large volumes of CO2 and likely having higher 

pressures within their storage formations than Class II ER projects. 

1
EPA clarifies that the Agency's UIC program or states with primary enforcement responsibility 

will oversee GS projects. 

For additional information on EPA’s final regulatory approach (including well construction 

requirements, monitoring, and post-injection site care and closure), please see the final rule and 

preamble as well as the rulemaking docket. 

Letter ID: 0110 Comment ID: 22036 Letter Lines: 27 to 52 

Comment Code: 1612 1.3.1.1 Leaching and mobilization of contaminants; reactions in injection 

zone 

Comment: Potential for Adverse Chemical Reactions: 

The corrosive nature of carbon dioxide in the presence of water was noted 

several times during the work sessions conducted during the late-February CO2 

sequestration meetings. [FN1: U.S. ENVIRONMENTAL PROTECTION AGENCY, Proposed 

UIC 

Regulations for Geologic Sequestration of Carbon Dioxide, Feb. 26-27, 2008.] 

Chemical reactions between the injected carbon dioxide and the pore water in the 

host rock should be expected, resulting in solution and redeposition of host 

mineral material and loss of pore volume. 

For thirty years, the reviewer worked as a geologist for Gulf Oil studying and 

analyzing thousands of surface and subsurface samples of sandstones and 

quartzite rocks 

from different parts of the world. Siliceous overgrowths on the quartz grains 

making up these rocks were common and in some instances resulted in the total 

loss of pore volume. The overgrowths ranged from amorphous silica, various 

cherts, cryptocrystalline quartz to quartz deposited in crystalline continuity 

with the host grains. [FN 2: Skolnick. H., The Quartzite Problem, JOUR. SED. 

PET. V.35, p.12-22 (1965), (The most extreme observed example was a core from 

Peru in which all of the pore volume was filled with the mineral pyrite)] Thus 

when the presence of silica is suspected in a CO2 stream,[FN 3: For instance, 

CO2 derived from the combustion of coal may contain significant levels of silica 

due to the presence of fly ash in the waste stream.] silica content should be 

determined prior to sequestration - particularly where storage in sandstone or 

quartzite formations is contemplated. 

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

including the potential for leakage of CO2 into USDWs, which could result in the mobilization 

of substances that could pose threats to human health by endangering 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. The mandate of the UIC Program under the SDWA is to protect public health by 

2
ensuring the protection of USDWs from endangerment. The GS rule accomplishes this through 

requirements tailored to address the unique nature of GS, including the large volumes of CO2 

injected, its buoyancy and potential corrosivity in the presence of water, and impurities in the 

CO2 stream. Many of these requirements specifically address the potential for mobilized 

substances to affect USDWs. 

For example, the owner or operator must submit data about the site, including information on the 

porosity, permeability, mineralogy, and geochemistry of the targeted injection and confining 

zones. Operators must also present information on the compatibility of the CO2 stream with 

fluids in the injection zone and minerals in both the injection and confining zones as specified at 

§146.82(c)(3). The data can help identify potential geochemical reactions between the injected 

CO2 and the host geologic formations, which could result in the plugging of pore spaces or the 

dissolution of formation minerals. During injection operations, operators must extensively 

monitor ground water quality to provide early detection of any unacceptable movement of fluids 

or impurities in the subsurface as specified in §146.90. Operators must 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 provide financial responsibility to address contamination 

as specified in §146.85. 

Letter ID: 0110 Comment ID: 22037 Letter Lines: 54 to 107 

Comment Code: 2044 1.5.2.2 Oppose Class VI/ Support Class II 

Comment Code: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ 

dividing line between Class II and Class VI (seeking comment) 

Comment: The Need for Class VI Wells: 

In the 2005 Energy Policy Act, Congress gave the Department of Energy the 

mission to investigate the gathering, transportation and injection of CO2 into 

oil and gas fields to increase production.[FN 4: 42 U.S.C. 15910.] On September 

6, 2006, the DOE announced its own program with a dual purpose of storing CO2 

and using the gas for enhanced oil recovery.[FN 5: DOE - Fossil Energy Techline: 

A Two-For-One Solution 

http://fossil.energy.gov/news/techlines/2006/06050-DOE_Awards_EOR_Project.html] 

According to the DOE, only about 10 per cent of the oil contained in an oil 

field is produced initially. Further production is achieved by injecting steam 

and water into the reservoir rock to overcome the viscosity of the remaining oil 

and move it into the collection wells. The oil industry has also been injecting 

CO2 into oil-bearing reservoirs since 1972. It has proven to be the most 

efficient enhanced recovery method to date. A major drawback has been its high 

cost even considering the current cost of oil. 

The CO2 used early on was produced from naturally CO2-containing rocks. To 

mitigate the cost of the CO2, a number of current projects use CO2 collected 

from the flue gasses of industrial plants, including the construction of 

dedicated pipelines to transport the CO2 to oil fields for enhanced recovery 

3
operations (one such example is the line from the Dakota Gasification Plant in 

Beulah, North Dakota to the Weyburn oil field in Saskatchewan, Canada. [FN 6: 

DOE, 2008, Fossil Energy: DOE's Oil Recovery R&D Programs, 

http://fossil.energy.gov/programs/oilgas/eor/ ] Ultimately with these additional 

technologies total production can be increased to 30 to 60% of the original oil 

in place. [FN 7: Id.] At the present time, given the current production of flue 

gas, there is enough storage space in existing depleted oil fields to sequester 

CO2 well into the next century.[FN 8: Schrag, D., Preparing to Capture Carbon, 

SCIENCE, p812-813, Feb. 9, 2007.] 

In contrast, the proposed Class VI wells will be newly drilled, and potential 

well sites will require extensive study to determine if the area’s geological 

characteristics are acceptable. Substantial savings of time and money would be 

realized if the EPA instead used the large number of Class II enhanced oil 

recovery/enhanced gas recovery wells that already exist. Oil and gas have been 

produced from some of these sites for many years, and the chemistry, reservoir 

characteristics, and geology of the sites have been extensively studied and 

understood. This is the class of wells that should be exploited first. 

A program with the dual mission of CO2 sequestration plus utilization of the gas 

in enhanced recovery of oil and gas has much more to offer in terms cost 

savings, time savings, and overall efficiency. Of equal significance is the 

increase in oil and gas production - particularly in light of concerns over US 

reliance on foreign oil and the present push for offshore drilling. The DOE 

estimates that given new CO2 technology existing oil fields can produce as much 

as an additional 500 thousand barrels per day by 2012 and as much as 2 million 

barrels per day by 2020.[FN 9: DOE supra note 6.] 

Finally, given the lower costs of CO2 sequestration in existing oil fields and 

the attendant increased oil production, sequestration in existing oil fields is 

also more likely to provide storage site operators with the financial resources 

necessary to ensure proper site closure and post-closure care, and to meet longterm financial assurance requirements. 

Individual Response: EPA clarifies that the purpose of the GS rule is not to promote GS in one 

type of formation over another. EPA clarifies that the purpose of the GS rule is to ensure 

protection of USDWs from endangerment. 

EPA clarifies that injection of carbon dioxide for the purpose of enhanced recovery is regulated 

under Class II requirements. Owners or operators may use depleted oil and gas reservoirs for GS 

provided the injection is intended for long-term storage and the well meets the standards in 

§146.86(a). EPA is allowing the construction of Class II EOR 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 from endangerment. 

4
EPA believes that injection for the primary purpose of long term storage is sufficiently different 

from Class II EOR operations and warrants tailored requirements. For example, the volume of 

CO2 anticipated to be injected in Class VI wells is significantly greater than for Class II wells. 

Reservoir pressure conditions will also be different, with Class VI injection operations involving 

large volumes of CO2 and likely having higher pressures within their storage formations than 

Class II EOR projects. 

Letter ID: 0110 Comment ID: 22038 Letter Lines: 103 to 107 

Comment Code: 5000 2.8 Proposed Well Plugging and Post-Injection Site Care Requirements 

Comment Code: 5400 2.9 Proposed Financial Responsibility and Long-Term Care 

Requirements 

Comment: Finally, given the lower costs of CO2 sequestration in existing oil fields and 

the attendant increased oil production, sequestration in existing oil fields is 

also more likely to provide storage site operators with the financial resources 

necessary to ensure proper site closure and post-closure care, and to meet longterm financial assurance requirements. 

Individual Response: EPA agrees with the commenter that depleted oil and gas reservoirs 

associated with ER operations may be used for CO2 storage and that these sites may be some of 

the first sites where commercial-scale GS is deployed. 

EPA clarifies that the goal of financial responsibility is to ensure that financial resources are 

available to prevent or remediate the endangerment of USDWs from improper plugging, 

remediation, and management of wells in the event that the owner or operator experiences 

financial difficulties. Assuring financial responsibility for corrective action on wells in the AoR, 

injection well plugging, PISC and site closure, and emergency and remedial response at GS sites 

is an important component of ensuring that USDWs are protected. 

EPA is developing guidance on financial responsibility for Class VI wells (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 may use to meet financial responsibility 

requirements for Class VI wells. 

Letter ID: 0110 Comment ID: 22039 Letter Lines: 109 to 121 

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

Comment: Agency Administration and Oversight 

The costs and logistics of large scale CO2 sequestration are mindboggling. 

Participating utilities will have to retrofit in order to collect, clean, 

compress, and store CO2; pipelines and storage depots must be constructed; and 

5
fleets of tanker trucks will be required for transport. Given the critical 

environmental and energy problems we face and the complexity of large scale CO2 

sequestration infrastructure, the CO2 sequestration program needs special 

oversight to keep costs down, maintain efficiency, minimize political 

interventions, and keep inter-agency squabbles out of the mix. The roles of 

relevant government agencies, particularly EPA and DOE, must be clarified in 

order to keep administration as uncomplicated as possible and provide strong 

oversight. 

Individual Response: EPA received a number of comments indicating that the Agency should 

further explore environmental and regulatory issues beyond the scope of the proposed SDWA 

requirements for underground injection of CO2 for GS. 

EPA acknowledges that GS falls within the broader context of CCS and the need for regulatory 

clarity to ensure that USDWs are protected from endangerment. In developing the final GS rule, 

the Office of Water coordinated with other Agency program offices and across federal agencies 

(e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy 

Management, Regulation, and Enforcement, formerly the Minerals Management Service; Bureau 

of Land Management). The Agency continues to evaluate areas of potential applicability of other 

Federal environmental statutes including, but not limited to: the Clean Air Act; the Resource 

Conservation and Recovery Act; the Comprehensive Environmental Response, Compensation, 

and Liability Act; and the Marine Protection, Research and Sanctuaries Act to various aspects of 

GS and CCS. The Agency will continue to coordinate on GS and CCS related issues to minimize 

redundancy and maximize efficiencies for owners or operators. For additional information, 

please see the discussion entitled "How Does This Rulemaking Relate to Other Federal 

Authorities and GS and CCS Activities?" in the preamble to the final GS rule. 

Regarding the need for a CCS agency to coordinate across agencies, EPA is coordinating with 

and will continue to facilitate communication among federal and state agencies during the 

implementation phase of the GS regulation. 

Letter ID: 0110 Comment ID: 22040 Letter Lines: 123 to 129 

Comment Code: 4620 2.6.2 Injectate monitoring 

Comment: Conclusion 

Regardless of what specific form the CO2 sequestration program ultimately takes, 

at a minimum, the program must ensure that: 

1. the chemistry of the CO2 and its contaminants is ascertained prior to 

injection; 

Individual Response: EPA agrees that monitoring of the injectate prior to and during injection 

is important to allow for comparison of baseline data and operational-phase monitoring results to 

provide warning of potential USDW endangerment. For this reason owners or operators must 

6
perform an analysis of the chemical and physical characteristics of the CO2 stream, as required 

at §146.82 (a)(7)(iv). In addition, Section §146.90(a) requires owners or operators to perform 

analysis of the CO2 stream during injection operations with sufficient frequency to yield data 

representative of its chemical and physical characteristics. 

Letter ID: 0110 Comment ID: 22043 Letter Lines: 125 to 126 ; 131 to 133 

Comment Code: 4620 2.6.2 Injectate monitoring 

Comment Code: 4630 2.6.3 Corrosion monitoring 

Comment Code: 4660 2.6.6 Geochemical monitoring 

Comment: Regardless of what specific form the CO2 sequestration program ultimately takes, 

at a minimum, the program must ensure that: 

2. the sequestered material’s behavior in the chemical, geological, and 

hydrological environment where it is stored is anticipated and carefully 

monitored; and 

Individual Response: EPA agrees with commenters on the importance of monitoring at GS sites 

and emphasizes that monitoring of injection activities must be an important component of every 

GS project. Monitoring associated with injection wells and the movement of the CO2 plume is 

necessary to verify that the injectate is confined in the target formations and does not endanger 

USDWs. The GS rule, at §146.90, requires injectate monitoring, mechanical integrity testing, 

corrosion monitoring, tracking the CO2 plume and area of elevated pressure, monitoring 

geochemical changes above the confining zone, and, at the discretion of the Director, surface air 

and soil gas monitoring for CO2 fluctuations, and any additional tests necessary to ensure 

USDW protection from endangerment. 

Letter ID: 0110 Comment ID: 24958 Letter Lines: 94 to 107 

Comment Code: 6000 3. Cost of the Proposed Rule 

Comment: A program with the dual mission of CO2 sequestration plus utilization of the gas 

in enhanced recovery of oil and gas has much more to offer in terms cost 

savings, time savings, and overall efficiency. Of equal significance is the 

increase in oil and gas production - particularly in light of concerns over US 

reliance on foreign oil and the present push for offshore drilling. The DOE 

estimates that given new CO2 technology existing oil fields can produce as much 

as an additional 500 thousand barrels per day by 2012 and as much as 2 million 

barrels per day by 2020.[FN 9: DOE supra note 6.] 

Finally, given the lower costs of CO2 sequestration in existing oil fields and 

the attendant increased oil production, sequestration in existing oil fields is 

also more likely to provide storage site operators with the financial resources 

necessary to ensure proper site closure and post-closure care, and to meet long7
term financial assurance requirements. 

Individual Response: EPA recognizes that there may be benefits (including cost savings) 

associated with transitioning ER projects to GS. The final GS regulation requires at §146.81(c) 

that owners or operators seeking to grandfather existing Class II wells for GS demonstrate that 

grandfathered 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 promoting GS is outside the scope of the GS rulemaking. Rather, the purpose of the GS 

regulation is to ensure that GS is conducted in a manner that protects USDWs from 

endangerment. For additional information on EPA's final regulatory approach, including 

transitioning of EOR wells for GS, please see the final rule and preamble. 

EPA is developing guidance on transitioning of EOR projects. This guidance will be available on 

EPA’s website at http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm. 

Letter ID: 0110 Comment ID: 29296 Letter Lines: 125 to 126 ; 135 to 136 

Comment Code: 5400 2.9 Proposed Financial Responsibility and Long-Term Care 

Requirements 

Comment: Regardless of what specific form the CO2 sequestration program ultimately takes, 

at a minimum, the program must ensure that: 

3. steps must be taken to ensure that site operators have sufficient financial 

resources to cover post-closure care and any potential future liability 

Individual Response: EPA agrees and clarifies that the goal of financial responsibility is to 

ensure that financial resources are available to prevent or remediate the endangerment of 

USDWs from improper plugging, remediation, and management of wells in the event that the 

owner or operator experiences financial difficulties. EPA agrees that assuring financial 

responsibility for corrective action on wells in the AoR, injection well plugging, PISC and site 

closure, and emergency and remedial response at GS sites is an important component of ensuring 

that USDWs are protected. 

8