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 CO 2 :

1. The potential for adverse chemical reaction of CO 2 and its contaminants

with the water/mineral environment of the host rock.

2. The need for Class VI wells given the advantages of CO 2 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 wate r was noted several

times during the work sessions cond ucted during the late-February CO 2 sequestration

meetings. 1 Chemical reactions betw een 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. E NVIRONMENTAL P ROTECTION A GENCY

, Proposed UIC Regulations for Geologic Sequestration of

Carbon Dioxide , Feb. 26-27, 2008. 

### G R O U P 

### A G A I N S T 

### S M O G 

### & P O L L U T I O N 

### , I N C



### . 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.orgfrom 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, cryp tocrystalline quartz

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

presence of silica is suspected in a CO 2 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 CO 2 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 CO 2 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 pr oduction is achieved by injecting steam a nd water into the

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

collection wells. The oil industr y has also been injecting CO 2 into oil-bearing reservoirs

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

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

The CO 2 used early on was produced from naturally CO 2 -containing rocks. To

mitigate the cost of the CO 2 , a number of current projects use CO 2 collected from the flue

gasses of industrial plants, including the cons truction of dedicated pipelines to transport

the CO 2 to oil fields for enhanced recovery ope rations (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 th ese additional technologies total production

2 Skolnick. H., The Quartzite Problem , J OUR

. S ED

. P ET . 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 Techlin e: A Two-For-One Solution http://fossil.energy.gov/news/techlines/200 6/06050-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 CO 2 well into the next century. 8

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

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

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

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

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

and the chemistry, reservoir characteristic s, 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 CO 2 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 si gnificance 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 CO 2 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 CO 2 sequestration in existing oil fields and the

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

to provide storage site operators with the fi nancial resources necessary to ensure proper

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

requirements.

Agency Administration and Oversight

The costs and logistics of large scale CO 2 sequestration are mindboggling.

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

CO 2 ; pipelines and storage depots must be constr ucted; and fleets of ta nker 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 , S CIENCE , p812-813, Feb. 9, 2007.

9 DOE supra note 6.the complexity of large scale CO 2 sequestration infrastructure, the CO 2 sequestration

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

political interventions, and keep inter-agenc y squabbles out of th e 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 CO 2 sequestration program ultimately takes,

at a minimum, the program must ensure that:

1. the chemistry of the CO 2 and its contaminants is ascer tained prior to injection;

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

hydrological environment where it is st ored is anticipated and carefully

monitored; and

3. steps must be taken to ensure that s ite 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 (GA SP) has three primary concerns regarding the geologic se questration of CO2:

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

the water/mineral environm ent 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 pote ntial risks associated with GS, including the potential that CO2 injection for GS may result in leaching of subsurface materials that could mobilize contaminants or compromi se pore space, and ther efore injectivity. The purpose of the Class VI requirements is to mini mize and mitigate potential or identified risks through proper site characterization, well cons truction, operation, monitoring, post-injection site care, and site closure. To ensure USDW protect ion and mitigate risks, the GS regulation requires the owner or operator of a Cla ss 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 injecti on zone and minerals in both the injection and confining zones (§146.82). This da ta 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 w ould address concerns that form ation 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 site s 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 di fferent 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. Reser voir pressure conditions will also be different, with Class VI injection opera tions involving large volumes of CO2 and likely having higher pressures within their storage forma tions than Class II ER projects.

1EPA clarifies that the Agency's UIC program or states with primary enforcement responsibility will oversee GS projects.

For additional information on EPA’s final regu latory approach (inc luding 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 cont aminants; 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 la te-February CO2 sequestration meetings. [FN1: U.S. ENVI RONMENTAL 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 rede position 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 s ubsurface samples of sandstones and quartzite rocks

from different parts of the world. Sili ceous overgrowths on the quartz grains making up these rocks were common and in so me instances resulted in the total loss of pore volume. The overgrowths ra nged 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 extrem e 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 wa ste stream.] silica content should be determined prior to sequestration - partic ularly where storage in sandstone or quartzite formations is contemplated.

Individual Response: EPA acknowledges that there are pote ntial risks associated with GS, including the potential for leakage of CO2 into USDWs, which could re sult 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 constr uction, operation, monitoring, post- injection site care, and site closure. The mandate of the UIC Program under the SDWA is to protect public health by

2ensuring the protection of USDWs from endangerm ent. The GS rule accomplishes this through requirements tailored to address the unique natu re 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 speci fically address the potential for mobilized

substances to affect USDWs.

For example, the owner or operator must submit da ta about the site, including information on the porosity, permeability, mineralogy, and geochemistry of the targeted injection and confining zones. Operators must also present informati on 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 coul d result in the plugging of pore spaces or the dissolution of formation minerals. During injection operations, operato rs must extensively monitor ground water quality to provide early de tection 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 addres s any adverse effects a ssociated with the GS operation as specified in §146.94 and provide financial responsibil ity 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 in jection 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 ga ve the Department of Energy the mission to investigate the ga thering, 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 recover y.[FN 5: DOE - Fossil Energy Techline:

A Two-For-One Solution http://fossil.energy.gov/news /techlines/2006/06050-DOE_Award s_EOR_Project.html] According to the DOE, only about 10 per cent of the oil cont ained in an oil field is produced initially. Further pr oduction is achieved by injecting steam

and water into the reservoir rock to over come 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 sin ce 1972. It has proven to be the most efficient enhanced recovery method to da te. 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 pl ants, including the construction of dedicated pipelines to transport the CO2 to oil fields for enhanced recovery

3operations (one such example is the line from the Dakota Gasification Plant in Beulah, North Dakota to the Weyburn oil fi eld in Saskatchewan, Canada. [FN 6: DOE, 2008, Fossil Energy: DOE's O il 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 ti me, given the current production of flue gas, there is enough storage space in existi ng depleted oil fields to sequester CO2 well into the next century.[FN 8: Sc hrag, D., Preparing to Capture Carbon, SCIENCE, p812-813, Feb. 9, 2007.]

In contrast, the proposed Cl ass VI wells will be newl y drilled, and potential well sites will require extensive study to determine if the area’s geological characteristics are acceptable. Substantia l 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 ma ny years, and the chemistry, reservoir characteristics, and geology of the site s 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 seque stration plus utiliz ation of the gas in enhanced recovery of oil and gas ha s much more to offer in terms cost savings, time savings, and overall effi ciency. Of equal significance is the increase in oil and gas pr oduction - particularly in li ght of concerns over US reliance on foreign oil and the presen t push for offshore drilling. The DOE estimates that given new CO2 technology ex isting 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 se questration in existing oil fields and the attendant increased oil production, se questration 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 pur pose of the GS rule is not to promote GS in one type of formation over another. EPA clarifies th at the purpose of the GS rule is to ensure protection of USDWs from endangerment.

EPA clarifies that inject ion 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 m eets the standards in §146.86(a). EPA is allowing the construction of Cl ass II EOR wells to be grandfathered per §146.81(c), provided the owner or oper ator can demonstrate to the Director that the wells were engineered and constructed to meet the requi rements at §146.86(a) and ensure protection of USDWs from endangerment.

4EPA believes that injection for th e 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 wi ll also be different, with Cla ss VI injection operations involving large volumes of CO2 and likely having higher pressures within th eir 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-In jection Site Care Requirements

Comment Code: 5400 2.9 Proposed Financial Respons ibility and Long-Term Care Requirements

Comment: Finally, given the lower costs of CO2 se questration in existing oil fields and the attendant increased oil production, se questration 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 CO 2 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 responsi bility is to ensure that financial resources are available to prevent or remediate the e ndangerment of USDWs from improper plugging, remediation, and management of wells in the event that the owner or operator experiences financial difficulties. Assuring fi nancial responsibility for correct ive action on wells in the AoR, injection well plugging, PISC and si te closure, and emergency and remedial response at GS sites is an important component of en suring that USDWs are protected.

EPA is developing guidance on financial responsibili ty for Class VI wells (available on EPA's website at http://water.epa.gov/t ype/groundwater/uic/wells _sequestration.cfm) that describes the types of financial instruments th at 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 sc ale CO2 sequestration are mindboggling. Participating utilities will have to retrofit in order to collect, clean, compress, and store CO2; pipelines and st orage depots must be constructed; and

5fleets 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, mainta in efficiency, minimize political interventions, and keep inter-agency s quabbles out of the mix. The roles of relevant government agencies , particularly EPA and DOE, must be clarified in order to keep administration as uncomp licated 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 in jection of CO2 for GS.

EPA acknowledges that GS falls within the broade r context of CCS and the need for regulatory clarity to ensure that USDWs are protected from endangerment. In develo ping 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 Stat es Geological Survey; Bureau of Ocean Energy Management, Regulation, and Enforcement, formerly the Minerals Management Service; Bureau of Land Management). The Agency continues to eval uate 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 Comprehe nsive Environmental Response, Compensation, and Liability Act; and the Marine Protection, Resear ch 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 entitle d "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 coordi nate 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 cont aminants 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

6perform 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 st ored is anticipated and carefully monitored; and

Individual Response: EPA agrees with commenters on the im portance of monitoring at GS sites and emphasizes that monitoring of injection activi ties must be an important component of every GS project. Monitoring associated with injecti on wells and the movement of the CO2 plume is necessary to verify that the injectate is confin ed in the target formations and does not endanger USDWs. The GS rule, at §146.90, re quires injectate monitoring, m echanical integrity testing, corrosion monitoring, tracking the CO2 plume and area of elevated pressure, monitoring geochemical changes above the confining zone, a nd, at the discretion of the Director, surface air and soil gas monitoring for CO2 fluctuations, a nd 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 seque stration plus utiliz ation of the gas in enhanced recovery of oil and gas ha s much more to offer in terms cost savings, time savings, and overall effi ciency. Of equal significance is the increase in oil and gas pr oduction - particularly in li ght of concerns over US reliance on foreign oil and the presen t push for offshore drilling. The DOE estimates that given new CO2 technology ex isting 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 se questration in existing oil fields and the attendant increased oil production, se questration 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 long7term 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 seeki ng to grandfather existing Class II wells for GS demonstrate that grandfathered wells were engine ered and constructed to meet the requirements at §146.86(a) and ensure protection of USDWs, in lieu of requi rements at §§146.86(b) and 146.87(a). EPA clarifies that promoting GS is outside the scope of th e GS rulemaking. Rather, the purpose of the GS regulation is to ensure that GS is conducted in a manne r that protects USDWs from endangerment. For additional information on EP A's final regulatory approach, including transitioning of EOR wells for GS, pleas e 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/we lls_sequestration.cfm.

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

Comment Code: 5400 2.9 Proposed Financial Respons ibility 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 s ite operators have sufficient financial resources to cover post-closure care and any potential future liability

Individual Response: EPA agrees and clarifies that the goa l of financial responsibility is to ensure that financial resources are available to prevent or remediate the endangerment of USDWs from improper plugging, remediation, and ma nagement of wells in the event that the owner or operator experiences financial diffi culties. EPA agrees that assuring financial responsibility for corrective action on wells in the AoR, injecti on well plugging, PISC and site closure, and emergency and remedi al response at GS sites is an important component of ensuring that USDWs are protected.

8