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.I offer my comments regarding proposed sequestr ation well rule offer by EPA on 25 July

2008 at 73 FR 43491-43541.

I have five concerns with sequestration of CO 2

.

A: CO2 SEQUESTRATION IS NOT NECE SSARY TO STOP GLOBAL WARMING

1. DOE compar ed the 2008 estimated CO2 emi ssions from anthropogenic sources with naturally occurring emissions, Fig 1. Based on the graph data, it is difficult to believe sequestering the anthropogenic releases will change anything.

2. The only accurate means of measuring the changing Global Temperature
is via satellite. Since 2001 the sate llite measurements show a decrease of 0.1°C per year, while the CO2 continues to increase..

3. The IPPC comp uter simulation of climate change predicts an “Atmospheric Hotspot” layer about 10 Km above the earth ’s surface as CO2 increases. Try as we have, the weather balloons hav e never recorded such a raise in temperature. This casts doubt on the va lidity of the IPPC Model and the need for CO2 sequestration.

B: EPA STATES THE NECESSARY MATE RIALS FOR THE COMPLETION OF
SEQUESTRATION INJECTION WELLS ARE NOT CURRE NTLY AVAILABLE.

1. CO2 when mixed with wa ter forms carbonic acid.

2. Well casing, valves, packer slips and connectors are typically manufactured

from carbon steel.

3. Carbon steel is highly corrosive when in contact with carbonic acid.

4. Stainless steel 404 is attacked by carbonic acid.

5. EPA suggests using stainless steel 316 for well heads on the basis on one Enhanced Oil Recovery injection well.

6. Cameron reports manufacturing only one SS 316 wellhead and Cameron does

not know the fate of the one 316 wellhead.7. My personal contact with the project consulting engineer fo r the well used by EPA resulted in no response regarding the corrosion resistance of SS 316.

8. EPA say in the proposed rule, “Not to worry” the Petroleum Industry will develop the need materials. This is the same industry EPA disparages. EPA in the proposed rule requires the completion materials to be corrosion restraint. I wish it was that easy.

9. Completion tubulars are held in place by Portland cement.

10. Portland cement is highly susceptible to Carbonic Acid attack.

11. EPA says, based on a Halliburton ad, safe cement is available.

12. Halliburton says they have tested corrosion resistant cement in the laboratory, under acce lerated conditions for 12 mont hs using weight loss as the

criteria of satisfaction. When asked if we ight loss is a satisfactory criterion the laboratory cement chemist said “We don’ t know.” EPA is relying on premature

data.

13. Sequestration of CO2 is forever. A 12 month test agai nst a questionable criterion appears unsafe.

14. Any existing wells penetrating the in jection zone is subject to failure.

15. EPA has approved Sequestration wells as Class I and/or Class II wells, even though adequate materials are not available.

C: WITHOUT TECHNICAL SUPPORT, EPA REQUIREs 50 YEARS OF
MONITORING EXECPT BY SAYING MO RE MONITORING IS EXPENSIVE.

1. Sequestration of CO2 is foreve r, or we don’t need capture the CO2 in the first place. If the CO2 escapes the Ea rth the World population is doomed, in accordance with the IPPC theory.

2. EPA provides no justification for selecting 50 years, in fact the proposed

rule states the economic c ontractor was told to develop the cost on the basis of 25 years.

3. It is unclear if the cost is based on 25 or 50 years.D. EPA RULE DOES NOT IM POSE ANY TECHNICAL QU LIFICATIONS ON THE

EPA PERMIT REVIEWER.

1. CO2 is injected in a supercr itical phase, e.g., 2200± psia.

2. CO2 is buoyant and becomes a gas as the pressure decreases.

3. CO2 sequestration looks like a money making scheme, so speculators will be

attracted.

4. EPA likens CO2 sequestration wells (Class VI wells) to Class II Enhanced oil/gas well, water injector wells and Class I hazardous waste disposal wells.

4. Class II well injected liquids are not co rrosive. Special care is exercised to make injected water O2 free to avoid corrosion.

5. Class I injected fluids are blended to avoid corrosion.

6. Class II Enhanced oil recovery CO2 inje ction wells reservoirs are produced until abandonment, which lower the pressure to about the original pressure, Unlike Class II wells, sequestration well will be abandoned at the maximum injection pressure.

7. CO2 sequestration will attract many s peculators, because of fast money during injection, but the speculators will fade away during the monitoring phase.

8. Speculators will write a good proposal without the technical expertise to conduct the drilling, completion and inject ion safely. Unqualified/untrained EPA reviewers will have difficulty recognizing a sound proposal from an unsatisfactory proposal. So unsafe projects will be approved.

9. Speculators will go out of business in 50 years, assuming they remain in business after the money ma king inject is completed.

10. EPA makes no provision in the rules for qualified EPA personnel to correct problem left by the speculators.

11. EPA says the Regional Administrators ha ve the authority to make technical

decisions.

12. Regional Administrators typi cally are not technically trained

13. I requested under a FOI letter, the num ber of Permit writer/reviewers who were graduate engineers. EPA refuse to respond by saying such information was protected by the privacy laws.14. At a minimum the proposed rule needs to require the EPA permit
writer/reviewer be a Professional Engineer who stamps ever permit demonstrating the competency of the well project design and the Regional Administrator must be a graduate engineer..

15. EPA require a P.E. stamp SPCC Plan s, a Plan of no real consequence, but, now, allows an EPA employee, who has not demonstrated competency to review and approve a massive vessel operating at 2200 psia.

E. EPA PROVIDES IN THE PROPOSED RULE NO MEANS OF ASSURING
CORRECTIVE ACCTION WILL BE TAKEN BY THE SEQUESTRATION PROJECT
OWNER.

1 EPA discusses in the proposed rule the difficulty of corrective action in the event of a project problem, but does not come to a resolution.

2. There is no assurance major oil and gas companies will operate the Class VI wells, since experienced engineers ar e needed to produce oil and gas for the

nation.

2. EPA discusses using the Interstate Oil and Gas Compact Commission (IOGCC) idea of charging each Class VI we ll operator a per ton injection fee to be use in the case of an emergency, but what fee should be charged? EPA had

no answer.

3. In Canada 4.6 percent of the sequestration wells leak. The chance of an CO2 leak appears real.

4. If a leak occurs under a home and the residents are asphyxiated, and the project owner has gone bankrupt, who is responsible?

5. EPA suggest they are in contact with a Federal Agency regarding funding for emergencies, but reading the references provided by EPA, the reader finds no reference to sequestration well funding. The reference is to transportation, perhaps transportation of CO2 by pipe line, but even that is not clear.

Based on my reading, the proposed EPA rule is not ready for promulgation. The proposal should be withdrawn.

RegardsG. H, Holliday, PhD, P.E., BCEE

P.O. Box 2508

Bellaire, TX 77402Figure 1. 2008 Estimated United States CO2

Emissions for 2008Letter ID: 0127 Commenter: George Holliday, PhD, PE, BCEE Organization: Holliday Environmental Services, Inc.

Letter ID: 0127 Comment ID: 23052 Letter Lines: 20 to 33

Comment Code: 1280 1.1.2.1 General comments on climate change/ global warming

Comment: A: CO2 SEQUESTRATION IS NOT NECESSARY TO STOP GLOBAL

WARMING

1. DOE compared the 2008 estimated CO2 emi ssions from anthropogenic sources with naturally occurring emissions, Fig 1. Ba sed on the graph data, it is difficult to believe sequestering the anthropogenic releases will change anything. 2. The only accurate means of measuring the changing Global Temperature is via

satellite. Since 2001 the sate llite measurements show a decrease of 0.1°C per year, while the CO2 continues to increase..

3. The IPPC computer simulation of climat e change predicts an "Atmospheric Hotspot" layer about 10 Km above the earth’s surface as CO2 increases. Try as we have, the weather balloons have never record ed such a raise in temperature. This casts doubt on the validity of the I PPC Model and the need for CO2 sequestration.

Individual Response: EPA notes that mitigating and modeling climate change is outside the scope of the Class VI GS rulemaking. EPA clarifies th at the purpose of the Class VI GS rule is to ensure consistency in permitting underground inje ction of CO2 at GS operations across the United States and provide requirements to prev ent endangerment of USDWs in anticipation of

the eventual use of GS to reduce CO2 emissions.

Letter ID: 0127 Comment ID: 23053 Letter Lines: 35 to 59

Comment Code: 3862 2.3.3.1 Use of corrosion-resistant construction materials (seeking comment)

Comment: B: EPA STATES THE NECESSARY MA TERIALS FOR THE COMPLETION OF SEQUESTRATION

INJECTION WELLS ARE NOT CURRENTLY AVAILABLE.

1. CO2 when mixed with water forms carbonic acid.

2. Well casing, valves, packer slips and connectors are typically manufactured

from carbon steel.

3. Carbon steel is highly corrosive when in contact with carbonic acid.

14. Stainless steel 404 is attacked by carbonic acid.

5. EPA suggests using stainless steel 316 for well heads on the basis on one Enhanced Oil Recovery injection well.

6. Cameron reports manufacturing only one SS 316 wellhead and Cameron does not

know the fate of the one 316 wellhead.

7. My personal contact with the project c onsulting engineer for the well used by EPA resulted in no response regarding the corrosion resistance of SS 316.

8. EPA say in the proposed rule, “Not to worry” the Petroleum Industry will develop the need materials. This is the same industry EPA disparages. EPA in the proposed rule requires the completion materials to be corrosion restraint. I wish it was that easy.

Individual Response: EPA disagrees that corros ion-resistant materials and cement do not exist

and the research literature descri bes several types of ce ments that have been used under corrosive

conditions.

EPA clarifies that Grade 316 stainl ess steel is not a specified mate rial. It is discussed in the preamble to the proposed rule as an example of materials that have been used successfully in

similar situations. The determination of the best mate rial to use is left for the Director to approve based upon case-specific informati on as provided under §146.86(b)(1).

EPA is developing guidance on the construction of Class VI wells. This guidance will be

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

Letter ID: 0127 Comment ID: 23054 Letter Lines: 61 to 74

Comment Code: 3864 2.3.3.2 Use of corrosion-resistant cements (seeking comment)

Comment: 9. Completion tubulars are held in place by Portland cement.

10. Portland cement is highly suscep tible to Carbonic Acid attack.

11. EPA says, based on a Halliburton a d, safe cement is available.

12. Halliburton says they have tested corrosion resistant cement in the laboratory, under accelerated conditions fo r 12 months using weight loss as the

criteria of satisfaction. Wh en asked if weight loss is a satisfactory criterion the laboratory cement chemist said “We don’t know.” EPA is relying on premature

data.

213. Sequestration of CO2 is forever. A 12 month test against a questionable criterion appears unsafe.

Individual Response: EPA disagrees that corros ion-resistant materials and cement do not exist. Industry experience of many decades in corrosive down-hole situations such as acid gas injection and production of natural gas with carbon dioxi de and hydrogen sulfide impurities shows that

materials are available that can re sist corrosive environments. Meye r (2007) lists several types of

cements that have been used under such corro sive conditions. EPA ac knowledges that studies have likely not been performed to prove a 50-ye ar life span for corrosion-resistant materials. However, there are two studies of wells that we re exposed to CO2 for approximately 30 years by Carey et al. (2007) and Crow et al. (2008). Although these studies are limited in the number of well material samples and the number of wells examined, the casing and cement sampled indicate fairly good condition (i.e., fairly signi ficant corrosion resistance) of well materials installed three decades ago. The best available corrosion-resistan t materials suited for each GS project will be determ ined by the Director.

EPA acknowledges that there is limited data on this subject, and believes that providing multiple barriers of protection is the most appropr iate approach to protecting USDWs from endangerment. The Agency plans to, every six years, collect and review project data on early GS projects as well as industry innovations on cementing incl uding the development of CO2- resistant epoxy cements to determine whether th e appropriate amount and types of information and appropriate documentation are being collecte d, and to determine if modifications to the requirements are appropriate or necessary.

See the discussion of Class VI well construction requirements in the preamble to the final GS rule for additional information. Additionally, EPA is developing guidance on the construction of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

Letter ID: 0127 Comment ID: 23055 Letter Lines: 76 to 79

Comment Code: 3860 2.3.3 Well component degradation

Comment: 14. Any existing wells penetrating the inje ction zone is subject to failure.

15. EPA has approved Sequestration wells as Class I and/or Class II wells, even though adequate materials are not available.

Individual Response: EPA acknowledges that any injection we ll can potentially fail. It is for this reason that the GS rule contains multiple , tailored requirements for the siting, operation, MIT, monitoring, reporting, plugging, and post-inject ion site care and site closure of Class VI wells to protect USDWs from endangerment.

EPA believes that adequate materials that are ap propriate for CO2 injection for GS exist. EPA believes that the requirement at §146.86(b)(1) that materials must meet or exceed standards developed by the American Petroleum Institute, ASTM International, or comparable standards

3acceptable to the Director invokes the expertise of these bodies without the added burden of a certification program. EPA is de veloping guidance on the construc tion of Class VI wells. This guidance will be available on EPA’s website at http://water.epa.gov/type/groundwat er/uic/wells_sequest ration.cfm. EPA clarifies that all wells used for CO2 injection for the pur pose of GS must meet requirem ents in the final GS rule.

Letter ID: 0127 Comment ID: 23056 Letter Lines: 81 to 92

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

Comment Code: 6210 3.2.1 Comments on the timeframe of the costing analysis (seeking comment)

Comment: C: WITHOUT TECHNICAL SUPPORT, EPA REQUIREs 50 YEARS OF

MONITORING EXECPT BY

SAYING MORE MONITORING IS EXPENSIVE.

1. Sequestration of CO2 is forever, or we don’t need capture the CO2 in the first place. If the CO2 escapes the Earth the World population is doomed, in accordance with the IPPC theory.

2. EPA provides no justification for selec ting 50 years, in fact the proposed

rule states the economic contractor was to ld to develop the cost on the basis of 25 years.

3. It is unclear if the cost is based on 25 or 50 years.

Individual Response: EPA disagrees that the monitoring timeframe was selected based on cost. In determining the post-injection site care-timef rame for the proposed regulation, EPA reviewed industry reports, existing envir onmental programs, and initial GS research studies. EPA provided a synthesis of pertinent results from GS m odeling studies in the preamble to the proposed regulation. Further explanation of this analys is was included in an EPA-prepared background

document that is available in the federal docke t for the GS rule, title d "Computational Modeling of Underground Injection of Carbon Dioxide for De termination of Area-of-Review and Potential Risk to Underground Sources of Drinking Water. " Based on review of th ese studies, modeling

results indicate that the CO2 plume stabilization may occur on the timeframe of 10-100 years

after the cessation of in jection. EPA believes that a 50-year default post-injection site care timeframe is a reasonable midpoint for most GS projects and availabl e data, including data submitted by commenters, do not support a different de fault timeframe, and has retained this in the final regulation. However, EPA recognizes that there may be site s where the 50 year post injection site care timeframe may be either not appropriate or more burdensome than necessary based on sitespecific conditions. For this reason, the GS rule o ffers owners or operators flexibility regarding

the duration of the PISC timefra me by: (1) allowing the Direct or discretion to shorten or lengthen the PISC timeframe during the post-in jection period based on site-specific data, pursuant to requirements at §146.93(b) ; or (2) affording the Director discretion to allow a Class VI well owner or operator to demonstrate, during the permitting process based on substantial

4data, that an alternative PISC timeframe may be appropriate if it ensu res non-endangerment of USDWs pursuant to requirements at §146.93(c).

EPA believes that a default post-injection site car e timeframe of 50 years, with flexibility to adjust the timeframe for a limited number of GS projects during the permitting process where

substantial data exists to demonstrate that an alternative timeframe would be protective of USDWs, or based on data collected during the PISC period, is appropriate to address the range of sites where GS is anticipated to occur, to ac commodate site-specific circumstances and various geologic conditions, and addre sses commenters’ concerns, wh ile ensuring USDW protection. Both approaches will utilize si te-specific data, and be based on pressure monitoring and USDW impacts.

Letter ID: 0127 Comment ID: 23057 Letter Lines: 94 to 147

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

Comment: D. EPA RULE DOES NOT IMPOSE ANY TECHNICAL QULIFICATIONS ON

THE EPA PERMIT

REVIEWER.

1. CO2 is injected in a supercri tical phase, e.g., 2200± psia.

2. CO2 is buoyant and becomes a gas as the pressure decreases.

3. CO2 sequestration looks like a money ma king scheme, so speculators will be

attracted.

4. EPA likens CO2 sequestration wells (Cla ss VI wells) to Class II Enhanced oil/gas well, water injector wells and Cl ass I hazardous waste disposal wells.

4. Class II well injected liquids are not corrosive. Special care is exercised to make injected water O2 free to avoid corrosion.

5. Class I injected fluids are blended to avoid corrosion.

6. Class II Enhanced oil recovery CO2 inj ection wells reservoirs are produced until abandonment, which lower the pressu re to about the original pressure, Unlike Class II wells, sequestration well will be abandoned at the maximum injection pressure.

7. CO2 sequestration will attract many specu lators, because of fast money during injection, but the speculators will fade away during the monitoring phase.

8. Speculators will write a good proposal without the technical expertise to

5conduct the drilling, completi on and injection safely. Unqualified/untrained EPA reviewers will have difficulty rec ognizing a sound proposal from an unsatisfactory proposal. So unsaf e projects will be approved.

9. Speculators will go out of business in 50 years, assuming they remain in business after the money making inject is completed.

10. EPA makes no provision in the rules fo r qualified EPA personnel to correct problem left by the speculators.

11. EPA says the Regional Administrators have the authority to make technical

decisions.

12. Regional Administrators typically are not technically trained

13. I requested under a FOI letter, the nu mber of Permit write r/reviewers who were graduate engineers. EPA refuse to respond by saying such information was protected by the privacy laws.

14. At a minimum the proposed rule needs to require the EPA permit writer/reviewer be a Professional Engineer who stamps ever permit demonstrating the competency of the well project design and the Regional Administrator must be a graduate engineer..

15. EPA require a P.E. stamp SPCC Plans, a Plan of no real consequence, but, now, allows an EPA employee, who has not de monstrated competency to review and approve a massive vessel operating at 2200 psia.

Individual Response: EPA disagrees that the people desi gning and regulating wells lack technical training for effective oversight of Class VI wells. Most permitting authority staff have years of experience with the current UIC injectio n well classes and have relevant specialties in geology, engineering, and related disciplines. Injection well ow ners and operators represent industries with decades of experience injecti ng a variety of fluids, including CO2. Regarding UIC requirements for staff qualifications, EPA cl arifies that only the Cl ass I hazardous waste injection well regulations at §§144.14(c)(9) and 144.63 (i) require that a prof essional engineer certify closure of the well.

Letter ID: 0127 Comment ID: 23058 Letter Lines: 149 to 172

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

Comment: E. EPA PROVIDES IN THE PROPOSED RULE NO MEANS OF ASSURING

CORRECTIVE ACCTION WILL BE TAKEN BY THE SEQUES TRATION PROJECT OWNER.

1 EPA discusses in the proposed rule the difficulty of corrective action in the

6event of a project problem, but doe s not come to a resolution.

2. There is no assurance major oil and ga s companies will operate the Class VI wells, since experienced engineers are n eeded to produce oil and gas for the

nation.

2. EPA discusses using the Interstate O il and Gas Compact Co mmission (IOGCC) idea of charging each Class VI well operato r a per ton injection fee to be use in the case of an emergency, but what f ee should be charged? EPA had no answer.

3. In Canada 4.6 percent of the sequestration wells leak. The chance of an CO2 leak appears real.

4. If a leak occurs under a home and th e residents are asphyxiated, and the project owner has gone bankrupt , who is responsible?

5. EPA suggest they are in contact with a Federal Agency regarding funding for emergencies, but reading the references provided by EPA, the reader finds no reference to sequestration well funding. Th e reference is to transportation, perhaps transportation of CO2 by pipelin e, but even that is not clear.

Individual Response: EPA expects the emergency and reme dial response requirements at §146.94 will encourage owners or operators to plan (during the permitting phase of a GS project) for any actions that would be necessary in the unlikely event of a GS pr oject-related emergency and ensure that operators know what entities and individuals must be not ified and what actions must be taken to expeditiously mitigate any emergency situations.

EPA clarifies that, if the owner or operator obtains evidence th at USDWs may be endangered or that leakage is occurring, he or she must cease injection, take all steps reasonably necessary to identify and characterize any release, notif y the Director, and implement the approved emergency and remedial response plan (§146.94(b )). Failure to respond to any evidence of USDW endangerment would be considered a viol ation of the UIC permit and would be subject to applicable civil, criminal, or administrative penalties.

In response to the comment about funding for em ergency actions or damage if the owner or operator were to go bankrupt, EPA clarifies that §146.85 requires owners or operators to demonstrate and maintain financial responsibilit y for performing any necessary remedial actions associated with the requirements at §146.94, incl uding the actions outlined in their GS projectspecific emergency and remedial response plan.

Letter ID: 0127 Comment ID: 23059 Letter Lines: 174 to 175

Comment Code: 1450 1.2.2.1 Oppose the GS rulemaking

Comment: Based on my reading, the proposed EPA rule is not ready for promulgation. The

7proposal should be withdrawn.

Individual Response: EPA believes that the creation of a new injection well class (VI) under the existing UIC Program is necessary to enable the use of GS as a climate change mitigation technology in a manner that protects USDWs from endangerment. EPA believes that the UIC Program, under the authority of the SDWA, provides a strong fram ework for regulating injection of CO2 for GS and adds that the GS regulati on 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 potenti al presence of impurities in captured CO2, and its mobility within subsurface geologic formations. EP A adds that the final GS rule includes a variety of changes from th e proposed rule that enhance and clarify the requirements and address public co mments on the proposed rule.

Letter ID: 0127 Comment ID: 23966 Letter Lines: 112 to 115

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: 6. Class II Enhanced oil recovery CO2 inj ection wells reservoirs are produced until abandonment, which lower the pressu re to about the original pressure, Unlike Class II wells, sequestration well will be abandoned at the maximum injection pressure.

Individual Response: EPA agrees that the nature and risk s associated with CO2 injection for long term storage are different from Class II CO2 injection for ER, and that tailored requirements for GS wells are appropriate and necessary to protect USDWs from endangerment. For this reason, the Agency tailored UIC requirements for Cl ass VI wells that addr ess the general risks deep injection may pose to USDWs and specifically address the unique nature of CO2 GS (i.e., very large volumes, very long time-periods , and reservoir pressure conditions).

EPA adds that, while at the time that injection op erations cease, pressures will be high (or at maximum), owners or operators of Class VI wells will be re quired to perform extensive postinjection site care and monitoring until pressure s decline to the point that USDWs are not endangered as required under §146.93. See the disc ussion of post-injection site care in the preamble to the final rule for additional information.

8