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.December 23, 2008

Water Docket U.S. Environmental Protection Agency Office of Water Docket (Mailcode 2822T) 1200 Pennsylvania Ave., NW Washington, DC 20460

RE: Comments On The Federal Requirements Under The Underground Injection Control (UIC) Progra m For Carbon Dioxide Geosequestration Wells, Proposed

Rule EPA

- HQ

- OW

- 2008

- 0390

Dear Water Docket:

The Association of Metropolitan Water Agencies (AMWA) appreciates the opportunity to comment on the proposed rule for permitting the geological sequestratio n of carbon dioxide. AMWA recognizes the importance of reducing carbon dioxide emissions to mitigate climate change impacts . O ur member utilities across the country are engaged in efforts to reduce their carbon footprint and greenhouse gas emissions in a myriad of ways

— from increased efficiency to green power projects. However, protecting our nation’s water supply from potential negative impacts of the development of carbon sequestration projects is paramount.

The attached document provides the association’s comments on the proposal. If EPA has any questions about our comments please contact me or Erica Brown, Director of Regulatory Affairs, at 202

- 331

- 2820.

Sincerely,

Diane VanDe Hei

Executive Directo r

Cc: Cynthia Dougherty, OGWDW Steve Heare, OGWDW BOARD OF DIRECTORS

President Brian L. Ramaley Newport News Waterworks

Vice President

James McDaniel LA Dept. of Water and Power

Treasurer Chips Barry Denver Water Department

Secretary Jerry N. Johnson D.C. Water and Sewer Authority

Mark Premo Anchorage Water and Wastewater Utility

David Modeer

Tucson Water

Michael Wallis East Bay Municipal Utility District

Robert Hunter Atlanta Department of Watershed Management

Irene Caminer Chicago Dep artment of Water Management

Don Broussard Lafayette Utilities System

John P. Sullivan, Jr.

Boston Water and

Sewer Commission

Patricia Mulroy Las Vegas Valley Water District

Emily Lloyd New York City DEP

David Rager

Greater Cincinnati Water Works

Sco tt Potter Nashville Water & Sewerage

Services

Edmund Archuleta

El Paso Water Utilities

Jeff Taylor

Houston Public Utilities Division

Charles M. Murrray

Fairfax Water

Chuck Clarke

Seattle Public Utilities

Diane VanDe Hei

Executive DirectorAMWA Comments On Proposed F ederal UIC Requirements For Carbon Dioxide Geosequestration Wells 1 Associati on of Metropolitan Water Agencies Comments On The Federal Requirements Under The Underground Injection Control (UIC) Program For Carbon Dioxide Geosequestration Wells, Proposed Rule

73 Federal Register 43492, July 25, 2008

Introduction

AMWA appreciates the opportunity to comment on the proposed rule for permitting the geological sequestration of carbon dioxide (CO 2 ). M any of the most critical impacts of global climate change will manifest themselves through the hydrologic system, and there is already s trong evidence that climate change is having an impact on the world’s

water resources

. AMWA recognizes the importance of reducing carbon dioxide emissions to mitigate climate change impacts. O ur member utilities across the country are engaged in efforts to reduce their carbon footprint and greenhouse gas emissions in a myriad of ways

— from increased efficiency to green power projects. However, protecting our nation’s water supply from potential negative impacts of the development of carbon sequestratio n projects is paramount.

Many strategies must be used to reduce greenhouse gases (GHG)

– from conservation to alternative energy sources. Carbon capture and sequestration (CCS) may be one tool in the toolbox, but it is not the silver bullet in that it does not reduce GHG but simply stores GHG underground. While it is important to perform the research to explore options for CCS, including the proper modeling of the subsurface dynamics and comprehensive monitoring of pilot and permitted sites, it is als o important to consider the permanent nature of sequestration. Our ability to predict how subsurface dynamics may change over the life of the sequestration is currently very limited. Carbon sequestration is still largely untested and prudence is necessar y to avoid any unintended consequences that could have long

- term effects on underground sources of drinking water (USDWs).

Therefore, AMWA recommends that the final regulation take a phased approach and prohibit the construction of

CO 2 sequestration well s in the following types of aquifers until more is known about the risks of CO 2 sequestration to USDWs as a result of the effects and dynamics of the fluid in the subsurface:

1. Aquifers currently used for potable water supply today, or

2. Aquifers where it can be demonstrated that the aquifer will be used for potable supply in the future. AMWA is not trying to block carbon sequestration but believes that unintended consequences to the nation's water supply can be avoided by initially prohibiting the construction of CO 2 wells in any aquifer for potable supply, and by waiting to construct sequestration wells through any USDW until there is a better understanding of the effects of carbon sequestration on the dynamics of the subsurface geology and geochem istry. EPA should then revisit this exclusion once the potential risk factors and un intended consequences to USDWs are better understood.

AMWA supports strong criteria for site selection, design and operation of carbon sequestration sites. EPA’s rule and any financial incentives put forth by other branches of government must avoid the manifestation of long

- term

risks from adverse site selection or design due to moral hazard . Moral hazard is the possibility that a party insulated from risk may behave differently from the way it would behave if it were fully exposed to the risk. A potential owner/operator of a CCS site that has liabilit y immunity for example, may have a tendency to act less carefully than it otherwise would, leaving another party to bear some responsibility for the consequences of those

actions.

There are many potential issues that affect water quality that are not dire ctly related to EPA’s authority under the Safe Drinking Water Act (SDWA), yet AMWA would like to note that many of these issues need to be addressed before carbon sequestration is fully deployed on a national scale. Specifically, AMWA believes that the

De partment of Energy (DOE) should develop feasibility and cost

- benefit analyses with respect to additional energy and water consumed under a CCS scenario versus traditional coal power plants and other engineering solutions forAMWA Comments On Proposed F ederal UIC Requirements For Carbon Dioxide Geosequestration Wells 2 GHG mitigation and reduction. Research regarding the water requirements for a CCS project and the study and consideration of future water quantity needs in the regions of potential geosequestration sites must be performed.

Climate change, drought, and the depletion of traditional gr ound water supplies due to population growth and land development are causing drinking water utility managers to look at new sources of drinking water that have not traditionally been considered as sources of drinking water. Coupled with improvements in d esalination and other treatment technologies, drinking water sources of high salinity are being used for water supply. AMWA

recommends that EPA reexamine the current classification of a USDW (i.e., a n aquifer with a total dissolved solids (TDS) concentrat ion of less than 10,000 mg/L ) when siting Class VI geosequestration wells. The potential need to use saline aquifers for potable supply, particularly in water

- stressed areas, should take precedence over the sequestration of carbon dioxide there.

AMWA su pports EPA’s rulemaking to provide a framework for the permitting of carbon sequestration wells, recognizing that state agencies are looking to EPA to provide this leadership since carbon sequestration wells are already being piloted, yet there is no compr ehensive federal standard currently in place. AMWA’s comments are comprised of general comments about the proposal as well as several responses to specific EPA requests for

comment.

General Comments

Protection of drinking water sources is our primary concern . AMWA is concerned about the potential for CCS projects to result in unintended, and possibly harmful, consequences to sources of drinking water. Much of the

work in the CCS arena is still in pilot or pre

- pilot phase. AMWA cautions against the pe rmitting of large scale CCS projects until protection of potable or potentially potable aquifers can be established as a primary concern, and information about DOE pilot projects and the effects of carbon sequestration on the subsurface and USDW can be

col lected and analyzed.

AMWA is also concerned about using saline aquifers for carbon sequestration. In a climate

- stressed and ultimately

water

- stressed world, it is quite possible that these aquifers will be used as drinking water supplies in the near

futur e. For example, EPA states in the rule proposal that deep saline aquifers that have >10,000 TDS will account for 88% of geosequestration sites. Many of these aquifers may actually be targeted for water supply.

The experience of drinking water systems in Florida and other areas has demonstrated that TDS measurements in USDWs are a moving target. The upper Floridan aquifer is currently about 8000 mg/L TDS. However, in pumping this already brackish aquifer

, the upwelling of more saline waters from below is occurring. In addition, some utilities are considering pumping from deeper wells with a higher salinity for drinking water supply and using

reverse osmosis to treat for TDS.

As the protection of current and future drinking water supplies is paramou nt, AMWA suggests that when there are competing uses in an aquifer

, the needs of the aquifer for drinking water supply should take precedence over other municipal or industrial uses and the risk of unintended impacts on potable water supplies is unacceptab le. AMWA suggests that EPA require a more rigorous scientific evaluation in the final rule about how potential risk to potable aquifers will be avoided in the site characterization for a CO 2 geosequestration project.

Drinking water utilities must be con sulted during the review of any CO 2 sequestration permit application. AMWA recommends that as part of the process, all drinking water utilities that draw from an aquifer in the area of review (AoR) of a potential CO 2 sequestration project should be infor med and consulted. In addition, AMWA recommends that local drinking water utilities be included in the AoR review process, as drinking water or potential drinking water sources may become threatened due to a change in plume direction or behavior. Public involvement also needs to be a mandatory part of the AoR reevaluation process.AMWA Comments On Proposed F ederal UIC Requirements For Carbon Dioxide Geosequestration Wells 3 Unintended consequences: There have been unintended consequences in the deployment of municipal disposal wells in Florida, and AMWA cautions EPA to be very cautious in allowin g for carbon sequestration wells to be drilled in areas that are not protected by a confining layer of bedrock. For example, AMWA believes that EPA should exclude certain formations such as basalt, shale, fractured karst and coal bed seams from Class VI CO 2 injection until more research about the appropriateness injection into these formations completed.

Regulatory alternative : EPA’s proposed Alternative 3 for permitting CO 2 geosequestration appears to be the best approach in that it would allow for proje cts to move forward. AMWA supports this approach because it provides the permitting authority with discretion to require additional information from owner/operators applying for a permit and to make case

- by

- case permitting decisions. This is important as water chemistry and subsurface geology differ widely across the country.

Class VI wells: AMWA agrees with EPA’s proposal to have CO 2 geosequestration wells permitted under a new UIC category

– Class VI

– as this is a new type of injection well. Howeve r, as there is limited modeling or monitoring data specific to UIC of CO 2 available, this data gathering and modeling must occur. AMWA has

additional comments about research needs below.

Aspects of permitting process:

 Well construction

o EPA’s proposal re quires that materials that meet or exceed industry standards must be compatible with injected CO 2 and “are designed for the life of the well”. As the CO 2 may be stored underground indefinitely, are concretes and other well materials designed to last forev er under the chemical and geological conditions expected in a carbon sequestration well? AMWA requests that EPA and DOE perform additional research and data collection in this area.

 Mechanical integrity testing

o AMWA supports EPA’s proposal for mechanical i ntegrity testing every year. This safeguard is necessary to protect drinking water supplies, as wells will be drilled through USDWs to reach confined bedrock for sequestration wells.

Research must be comprehensive and must continue to increase our limit ed understanding of this technology. Class VI is a new unique type of well category that needs to have theoretical research (i.e., modeling) and monitoring performed, as well as other data gathered, to better understand how CO 2 sequestration will affect

g roundwater and the subsurface geology. The research must include a combination of good theoretical work and sound observational work as we are entering uncharted territory. While CO 2 has been used for gas extraction, under geosequestration, CO 2 would be put in the ground permanently. As a result, AMWA has the following

recommendations for research:

o Before any CO 2 geosequestration projects are fully deployed, more research is needed to allow EPA and/or DOE to develop a risk assessment for the technology, t aking into account risks to USDWs.

o The effectiveness of available risk management methods must be demonstrated. This is also recommended by the IPCC in its Summary for Policymakers.

o Groundwater modeling is improving and variable density flow models for deeper aquifers can be used with reasonable accuracy for understanding subsurface flow and quality. However these models must take variables such as heat transport into account to better translate to a CO 2 geosequestration scenario.

o Data can and should b e gathered immediately and more core analysis should be required in the permitting process

– specifically for key formations and for water/rock/gas interaction.

o Rock cores and thorough geochemical analysis of geosequestration should happen even before th e AoR. Advances in research and subsurface modeling make it possible to analyze the interaction between rock

formations and CO 2 . Performing these analyses early on could potentially prevent unintended

consequences.

o Potential ancillary effects of CCS

– su ch as pressure waves, which could move hundreds of miles and affect sequestration sites

– must be evaluated.AMWA Comments On Proposed F ederal UIC Requirements For Carbon Dioxide Geosequestration Wells 4 o Effects of CCS on saline aquifers are unknown. CO 2 geosequestration modeling performed to

- date has generally not considered this type of aquifer. This modeling must be conducted.

Specific Comments

EPA requests comments on several aspects of the proposed rule. AMWA’s response to several of these requests follows.

 73 FR 43502

- EPA seeks comment on the approach to grandfather construction requi rements at the Director’s discretion for existing Class I, Class II, and Class V wells seeking to convert to Class VI wells, and whether additional construction requirements would be necessary to prevent endangerment to USDWs from the GS of

CO 2 . Additional ly, EPA seeks comment on how the grandfathering approach for existing wells may affect compliance with the requirements in this proposal. Response: AMWA recommends that any well being considered for injection of CO 2 be required to meet the

same standards a s detailed in EPA’s rule for class VI wells. For example, the wells must be constructed

with the same corrosion

- resistant materials required under the rule. AMWA is new to the details of the UIC program and is concerned that wells constructed under Class I, II and V requirements may not have the same protective measures required in EPA’s proposed regulation, such as the down

- hole shutoff valve. AMWA recommends that if EPA proceeds with allowing for wells already constructed to be grandfathered

and conver ted to Class VI wells that the owner/operator of the well must conclusively demonstrate, through modeling, monitoring and other appropriate data, that the well can be operated in compliance with all requirements of the final rule.

 73 FR 43503

– EPA req uests comment on prohibiting injection into unmineable coal seam formations if they

are above the lowermost USDW. Response: AMWA opposes the injection of CO 2 into coal seams in general and as stated earlier

recommends that EPA and DOE conduct additional re search to determine the impacts of CO 2 storage on coal seams. Furthermore, AMWA opposes the injection into any formation above the lowermost existing or potential USDW and recommends that EPA only allow for the injection of CO 2 into formations below the

l owermost existing or potential USDW. Congress intended the UIC program to protect sources and potential sources of drinking water from contamination: “Underground injection endangers drinking water sources if such injection may result in the presence in underground water which supplies or can reasonably be expected to supply any public water system of any contaminant, and if the presence of such contaminant may result in such system’s not complying with any national primary drinking water regulation or ma y otherwise adversely affect the health of persons.” SDWA § 1421(d)(2); 42 U.S.C. § 300h(d)(2).

AMWA believes that allowing the injection of CO 2 above a USDW would endanger the USDW by providing a pathway for CO 2 to contaminate a drinking water source, es pecially if a well was constructed through a CO 2 plume.

 73 FR 43507

- EPA seeks comment on requiring the reevaluation of the site AoR on a periodic basis, under what conditions the AoR should be reevaluated, and the appropriateness of a 10 year minimum f ixed frequency for AoR reevaluation. Response: As carbon sequestration is an emerging technology that has not yet been tested on a large scale in the U.S., AMWA believes at this time that a ten

- year minimum frequency for AoR evaluation is not

sufficient. AMWA recommends instead that the AoR be reevaluated annually for the first ten years of the project and then every five years for the remaining operating period of the project.

AMWA also recommends that the final rule include criteria to trigger a shor ter review period at earlier intervals should monitoring detect a sudden change in CO 2 plume movement, size or pressure. In addition,AMWA Comments On Proposed F ederal UIC Requirements For Carbon Dioxide Geosequestration Wells 5 AMWA recommends that local drinking water utilities be included in the AoR review process, as existing or potential drink ing water sources could become threatened due to a change in plume direction or behavior. Public involvement also needs to be a mandatory part of the AoR reevaluation process.

 73 FR 43510

- EPA seeks comment regarding requirements for degradation

- resista nt well construction
materials, such as acid

- resistant cements and corrosion resistant casing. Response: AMWA agrees that cement and other materials used for carbon sequestration well construction must be resistant to corrosion and other potential chemica l reactions in the subsurface. As stated earlier AMWA also recommends that additional materials research be performed.

 73 FR 435110

- EPA seeks comment on the merits of requiring down

- hole shut

- off valves in geosequestration

wells. Response: AMWA suppor ts requiring down

- hole shut

- off valves in all geosequestration wells as these valves could provide a line of defense against contamination of USDW in the event of a defective injection

process.

 73 FR 43512

– EPA requests comment on whether CO 2 injection s hould be allowed into an injection zone above the lowermost USDW, when the Director determines that geologic conditions exist that will prevent fluid movement into adjacent USDWs. Response: AMWA opposes the injection into any formation above the lowermost existing or potential USDW and recommends that EPA take a phased approach and prohibit the construction of CO 2 sequestration wells in aquifers currently used for drinking water supply or expected to be used in the future,

until more is known about the risk s of CO 2 sequestration to USDWs as a result of the effects and dynamics of the fluid in the subsurface. Congress intended the UIC program to protect sources and potential sources of drinking water from contamination: “Underground injection endangers drink ing water sources if such injection may result in the presence in underground water which supplies or can reasonably be expected to supply any public water system of any contaminant, and if the presence of such contaminant may result in such system’s not c omplying with any national primary drinking water regulation or may otherwise adversely affect the health of persons.” SDWA § 1421(d)(2); 42 U.S.C. § 300h(d)(2).

AMWA believes that allowing the injection of CO 2 above a USDW would endanger the USDW by

prov iding a pathway for CO 2 to contaminate a drinking water source, especially if a well was constructed through a CO 2 plume.

 73 FR 43512

– EPA is also requesting comment on whether aquifer exemptions should be allowed for the purpose of Class VI injection, and under what conditions should such aquifer exemptions be approved. Response: AMWA does not believe it is prudent to allow for aquifer exemptions for the purpose of Class VI injection as saline aquifers not currently used for USDWs could be considered v iable drinking water supply in a water

- stressed environment. AMWA strongly believes that the use of an aquifer for drinking water supply should take precedence over all other municipal or industrial uses.

 73 FR 43523

- EPA proposes that Class VI injec tion well permits would be issued for the operating life of the GS project including the post

- injection site care period. EPA seeks comment on the merits of this approach. Response: AMWA does not support issuing an operating permit for the life of the seq uestration site. Instead, AMWA recommends issuing a lifetime operating permit for the coal plant, but with a separate and renewable permit for the operation of the geologic sequestration process. Drinking water treatment plants must notify state regulato rs of changes in ownership, management, or operations, and AMWA recommends that owner/operators of CCS sites be required to provide the same type of information to the Director in theAMWA Comments On Proposed F ederal UIC Requirements For Carbon Dioxide Geosequestration Wells 6 event of changes. In addition, AMWA recommends that owner/operators be r equired to periodically re

evaluate their injectate stream for any emerging contaminants, and remove them if required.

As CCS is a developing technology, AMWA recommends that EPA have a plan to update the regulation as additional information is gathered th rough research and through data and observations collected fro m permitted sites. Having a permit renewal schedule built into the process will allow the Director to ensure that updates to the regulation are included in permit renewals. AMWA also suggests t hat the permit application process include a review of the site operations to see if any instances of unsafe operation or changes in regulation would require a change in the plant operation.

 73 FR 43519

- EPA requests comment on the proposed use of a ten tative 50

- year fixed [post injection site care] timeframe that could be modified at the Director’s discretion based on monitoring and modeling data. Response: AMWA supports a minimum 50

- year time frame for post

- injection site care and recommends

that the Director not be given any discretion to shorten this time period. EPA notes in the proposal that “ the potential risks of endangering USDWs will not decline within that timeframe given that stabilization may

continue for several decades.” AMWA also recomm ends that additional research be conducted to better

understand the movement of CO 2 plumes and that EPA provide guidance to owner/operators about the criteria for monitoring and modeling data that would be necessary to demonstrate that the plume has stabil ized and justify site closure.

Conclusion

In conclusion, AMWA again stresses the need for more research using the improved groundwater modeling techniques and variable density flow models for deeper aquifers now available. In addition, EPA must gather

d ata now and in the future to better understand the behavior of CO 2 plumes and the interaction between water,

CO 2 and bedrock formations.

Above all, drinking water needs should be considered paramount and EPA should consider the future drinking

water nee ds of the country in light of climate change. EPA’s final rule should protect current and future USDWs from unintended consequences of CO 2 geosequestration and moral hazard.

AMWA appreciates the opportunity to comment on EPA’s proposal. GHG reduction an d mitigation measures including carbon sequestration are, understandably, very important issues to our members. As CCS technology has not been widely deployed in the U.S. to date, AMWA urges EPA and DOE to continue to perform the research suggested in the se comments as well as follow

- up assessments of the technology once deployed.

AMWA also recommends that EPA commit to update the rule regularly as more becomes known about CCS technology and the behavior of CO 2 injected into the subsurface. AMWA recomm ends that EPA work to update the rule every three to five years for the foreseeable future, as this technology will become more prevalent and injection methods and other sequestration techniques will likely improve. In developing this proposal, EPA has de monstrated its ability to quickly bring staff up to speed on this technology and AMWA believes the Agency must continue to take a strong interest in keeping up with technological advances.Letter ID: 0213

Commenter: Diane VanDe Hei Organization: Association of Metro politan Water Agencies (AMWA)

Letter ID: 0213 Comment ID: 22914 Letter Lines: 28 to 36 ; 115 to 117

Comment Code: 1610 1.3.1 Risks to USDWs

Comment: The Association of Metropolitan Water Agencies (AMWA) appreciates the opportunity to comment on the proposed rule for permitting the geological sequestration of carbon dioxide. AMWA r ecognizes the importance of reducing carbon dioxide emissions to mitigate climate change impacts. Our member

utilities across the country are engaged in effo rts to reduce their carbon footprint and greenhouse gas emissions in a myriad of ways -- from increased efficiency to green power projects. However, protecting our nation’s water supply from potential negative impa cts of the development of carbon sequestration projects is paramount.

sequestration is currently very limited. Carbon sequestration is still largely untested and prudence is necessary to a void any unintended consequences that could have long-term effects on underground sources of drinking water (USDWs).

Individual Response: EPA believes that sufficient data and experience curre ntly exist to develop regulations for Class VI wells. The GS rulemaking builds upon decades of knowledge about safe injection practi ces regulated by the UIC Program. While developing the GS regulation, EPA has evaluated rele vant GS research, including projects conducted by the seven Regional Carbon Sequestration Pa rtnerships (RCSPs) funded by DOE and coordinated through the National Energy Technology Laboratory (NETL) , and several international projects.

Letter ID: 0213 Comment ID: 22915 Letter Lines: 95 to 103

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

Comment: AMWA appreciates the opportunity to comm ent on the proposed rule for permitting the geological sequestration of carbon dioxi de (CO2). Many of the most critical impacts of global climate change will ma nifest themselves through the hydrologic system, and there is already strong eviden ce that climate change is having an impact on the world’s water resources. AMWA recognizes the importance of reducing carbon dioxide emissions to mitigate climate change impacts. Our member

utilities across the country are engaged in effo rts to reduce their carbon footprint and greenhouse gas emissions in a myriad of ways -- from increased efficiency to green power projects. However, protecting our nation’s water

Individual Response: The use of and investment in climate change mitigation technologies is outside the scope of the Class VI GS rulemaki ng. The Class VI GS requi rements are designed to

1ensure that, where GS is deployed, projects are permitted, sited, constructed, operated, and closed in a manner that protects USDWs from endangerment.

Letter ID: 0213 Comment ID: 22916 Letter Lines: 103 to 105

Comment Code: 1610 1.3.1 Risks to USDWs

Comment: efficiency to green power projects. However, protecting our nation’s water supply from potential negative impa cts of the development of carbon sequestration projects is paramount.

Individual Response: EPA recognizes that injecting large volumes of CO2 for GS poses unique challenges that, if not properly managed, could endanger drinking water s ources or have other adverse impacts. EPA agrees that caution is warr anted and has, as a result, developed a new well class with requirements tailored to address the unique challenges posed by GS and potential risks associated long-term injection of CO2. These re quirements include the ta ilored AoR delineation process per §146.84, monitoring that is appropriate to GS projects per §146.90, and extended post-injection s ite care per §146.93.

Letter ID: 0213 Comment ID: 22917 Letter Lines: 107 to 115

Comment Code: 1510 1.2.2.3 Need for additional study

Comment: Many strategies must be used to re duce greenhouse gases (GHG) -- from conservation to alternative energy sources . Carbon capture and sequestration (CCS) may be one tool in th e toolbox, but it is not the silver bullet in that it does not reduce GHG but simply stores GHG underground. While it is important to perform the research to e xplore options for CCS, incl uding the proper modeling of the subsurface dynamics and comprehens ive monitoring of pilot and permitted sites, it is also important to consider the permanent nature of sequestration. Our ability to predict how subsurface dyna mics may change over the life of the sequestration is currently very limited. Carbon sequestration is still largely

Individual Response: EPA agrees that GS is a key clim ate change mitigation technology, one that is part of a portfolio of options that could be deploye d to reduce CO2 emissions. Other options could include efficiency improvements a nd the use of alternative fuels and renewable energy sources. The purpose of the GS regulation is to assure that where deployed, GS is conducted in a manner that protects USDWs from endangerment. EPA agrees that continued

research in all GS associated fields will be integral to development of GS technology. EPA is using an adaptive approach to regulating CO2 inj ection for GS. EPA plans, every six years, to collect and review data on GS projects to dete rmine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are appropriate or necessary.

2Letter ID: 0213 Comment ID: 22918 Letter Lines: 119 to 134

Comment Code: 1510 1.2.2.3 Need for additional study

Comment Code: 1610 1.3.1 Risks to USDWs

Comment: Therefore, AMWA recommends that the final regulation ta ke a phased approach and prohibit the construction of CO2 sequestr ation wells in the following types of aquifers until more is known about the ri sks of CO2 sequestration to USDWs as a result of the effects and dynamics of the fluid in the subsurface:

1. Aquifers currently used for pot able water supply today, or

2. Aquifers where it can be demonstrated that the aquifer will be used for potable supply in the future. AMWA is not trying to block carbon sequestration but believes that unintended consequen ces to the nation's water supply can be avoided by initially prohibiting the cons truction of CO2 wells in any aquifer for potable supply, and by waiting to cons truct sequestration wells through any

USDW until there is a better understanding of th e effects of carbon sequestration on the dynamics of the subsurface geology and geochemistry. EPA

should then revisit this exclusion on ce the potential risk factors and unintended consequences to USDWs are better understood.

Individual Response: EPA clarifies that the final regulati on does not allow injection of carbon

dioxide into USDWs. USDWs incl ude both currently used sources and sources that may be used in the future. Under §144.3 a USDW is defined as an aquifer or portion of an aquifer that supplies any public water system or that contai ns a sufficient quantity of ground water to supply a public water system, and currently supplies dr inking water for human consumption, or that contains fewer than 10,000 mg/L total dissolved so lids and is not an exempted aquifer. The GS rule requires injection below the lowermost US DW, unless the owner or operator obtains a waiver from this requirement, in which case inje ction may occur into non-USDWs that lie above or between USDWs, provided the requirements at §146.95 are met. The final rule also allows for the expansion of the areal exte nt of existing aquifer exempti ons for Class II EOR/EGR wells transitioning to Class VI in jection for GS pursuant to requirements at §§146.4 and 144.7(d).

Please see the discussion of "Cla ss VI Injection Depth Waivers and Use of Aquifer Exemptions for GS" in the preamble to the fina l rule for additional information.

The Agency acknowledges the commenter’s concer ns about water resources and future water resource availability. The prim ary goal of the UIC Program under the SDWA is to protect USDWs from endangerment. Consistent with SDWA §1422, the UIC program provides that no injection shall be authorized if it results in the movement of fluid containing any contaminant into USDWs, if the presence of that contaminant may cause a vi olation of any primary drinking water regulation or may adversely affect th e health of persons as specified in §144.12.

The GS rule, as part of the UIC program regulations, continues the Program’s mandate under the SDWA of ensuring the protection of USDWs from endangerment. EPA expects that the tailored

3permitting, siting, construction, operation, monitoring, and post-injection site care requirements in the GS rule will prevent leakage from injection formations and protect USDWs.

Letter ID: 0213 Comment ID: 22919 Letter Lines: 136 to 137

Comment Code: 3100 2.1 Proposed Geologic Siting Requirements (40 CFR 146.83)

Comment: AMWA supports strong criteria for site selection, design and operation of carbon sequestration sites. EPA’s rule and any financial incentives put forth by other

Individual Response: EPA agrees with the commenter. Th e GS requirements are designed to ensure protection of USDWs from endangerment by requiring that injection wells are permitted, sited, constructed, operated, monito red, and plugged in a manner that does not endanger USDWs as informed by extensive, site-spe cific site characterization data.

Letter ID: 0213 Comment ID: 22920 Letter Lines: 137 to 144

Comment Code: 1600 1.3 Risk Associated with CO2 GS

Comment: sequestration sites. EPA’s rule and any financial incentives put forth by other branches of government must avoid the ma nifestation of long-term risks from adverse site selection or design due to moral hazard. Moral hazard is the possibility that a party insulated from ri sk may behave differently from the way it would behave if it were fully exposed to the risk. A potential owner/operator of a CCS site that has liability immunity for example, may have a tendency to act less carefully than it otherwise woul d, leaving another party to bear some responsibility for the conse quences of those actions.

Individual Response: EPA clarifies that the GS rule does not insulate owners or operators from risk. The GS rule requires that owners or operators demonstrate and maintain financial responsibility for corrective action on wells in the AoR, injection well plugging, post-injection site care and site closure, and emergency and reme dial response at GS si tes, as specified in §146.85. In the event of contamination or other a dverse event that endang ers a USDW during the life of the project, the financial instrument(s), such as insurance, bonds, etc., rather than public monies, would cover necessary resp onse actions to remediate the USDW. EPA clarifies that it is the owner or operator of the well who will be requ ired to demonstrate financial responsibility, not the generator of the CO2, c onsistent with EPA’s authority under SDWA. Furthermore, EPA

notes that tort and other remedies will continue to be available after site closure. Other Federal environmental statutes, e.g. Clean Air Act, 42 U.S.C. §§7401-7671; CERCLA, 42 U.S.C. §9601- 9675; and RCRA, 42 U.S.C. §6901-6992, potentially a pply as well to the risks created by the long-term storage of CO2.

EPA adds that Class VI well owne rs and operators must site, cons truct, operate, monitor, and close their wells in a manner that protects USDW s, and Class VI permits will set forth rigorous technical requirements to ensure careful planning, operation, and cl osure of GS projects. Failure

4to meet these requirements would be considered a violation of th e permit and would be subject to applicable civil, criminal, or administra tive penalties under SDWA §1423. The comment regarding financial incentives pu t forward by other federal agencies is outside the scope of this rulemaking.

Letter ID: 0213 Comment ID: 22921 Letter Lines: 146 to 156

Comment Code: 1510 1.2.2.3 Need for additional study

Comment: There are many potential issues that affect water quality that are not directly related to EPA’s authority under the Safe Drinking Water Act (SDWA), yet AMWA would like to note that many of these issu es need to be addressed before carbon sequestration is fully deployed on a national scale. Specifically, AMWA believes that the Department of Energy (DOE) should develop feasibility and cost-benefit analyses with respect to additional energy and water consumed under

a CCS scenario versus traditional coal power plants and other engineering solutions for GHG mitigation and reducti on. Research regarding the water requirements for a CCS project and the st udy and consideration of future water quantity needs in the regions of poten tial geosequestration sites must be performed.

Individual Response: EPA clarifies that cost -benefit analysis of CCS and other greenhouse gas mitigation technologies and the water resource requirements for CCS are outside the scope of this rulemaking.

Letter ID: 0213 Comment ID: 22922 Letter Lines: 158 to 168

Comment Code: 1270 1.1.2 Comments on other rules/issues

Comment: Climate change, drought, and the depleti on of traditional ground water supplies due to population growth and land developm ent are causing drinking water utility managers to look at new sources of dri nking water that have not traditionally been considered as sources of drinking water. Coupled with improvements in

desalination and other treatment technol ogies, drinking water sources of high salinity are being used for water supply. AMWA recommends that EPA reexamine

the current classification of a USDW (i.e., an aquifer with a total dissolved solids (TDS) concentration of less th an 10,000 mg/L) when siting Class VI geosequestration wells. The potential need to use salin e aquifers for potable supply, particularly in water-stressed areas, should take precedence over the sequestration of carbon dioxide there.

Individual Response: EPA clarifies that addressing climat e change, drought, and the depletion of traditional ground water supplies are outside th e scope of the Class VI GS rulemaking. Rather, the purpose of the Class VI GS rule is to ensu re consistency in permitting underground injection of CO2 at GS operations across the United St ates and provide requirements to prevent

5endangerment of USDWs in anticipation of the eventual use of GS to reduce CO2 emissions.

The Agency acknowledges commenter concerns a bout water resources and future water resource availability. However, modifying the definition of a USDW is outsi de the scope of the Class VI GS rulemaking. USDWs are defined as aquifers currently being used as sources of drinking water or those capable of supplying a public wa ter system and have a total dissolved solids (TDS) content of 10,000 milligrams per liter or less (§144.3).

The primary goal of the UIC progr am under the SDWA is to protec t USDWs in order to ensure a reliable supply of drinking water for the American public. The Class VI GS rule, as part of the UIC program regulations, continues the program ’s tradition of ensu ring the protection of USDWs. The permitting, siting, construction, opera tion, monitoring, and post-injection site care requirements in the GS rule build on a long-stan ding protective regulatory framework, tailored to the unique characteristics of CO2 injected for the purpose of GS.

Letter ID: 0213 Comment ID: 22923 Letter Lines: 170 to 175

Comment Code: 1420 1.2.1.1 Support the GS rulemaking

Comment: AMWA supports EPA’s rule making to provide a framework for the permitting of carbon sequestration wells, recognizing that state agencies ar e looking to EPA to provide this leadership since carbon sequestration wells are already being piloted, yet there is no comprehensive fe deral standard currently in place. AMWA’s comments are comprised of general co mments about the proposal as well as several responses to specific EPA requests for comment.

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 agrees 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.

Letter ID: 0213 Comment ID: 22924 Letter Lines: 179 to 186

Comment Code: 1510 1.2.2.3 Need for additional study

Comment Code: 1610 1.3.1 Risks to USDWs

Comment: Protection of drinking water sources is our primary concern. AMWA is concerned about the potential for CCS projects to result in unintended, and possibly harmful, consequences to sources of drinki ng water. Much of the work in the CCS arena is still in pilot or pre-pilot phase. AMWA cauti ons against the permitting of large scale CCS projects until protecti on of potable or po tentially potable

6aquifers can be established as a primar y concern, and information about DOE pilot projects and the effects of carbon sequestration on the subsurface and USDW can be collected and analyzed.

Individual Response: As described above, EPA believes th at sufficient data and experience currently exist to develop regulations for Cla ss VI wells. While developing the GS regulation,

EPA evaluated relevant GS res earch, including projects conducted by the seven Regional Carbon Sequestration Partnerships (RCSPs) funded by DOE and coordinated through the National Energy Technology Laboratory (NETL), and several international projects.

EPA agrees that continued research will be in tegral to development of GS technology, but disagrees that the Agency should wait for all cu rrent field research to be complete before finalizing the GS rule. The Agency believes th at establishing a regulat ory framework for the future development and deployment of CCS tec hnology provides a framework for injecting CO2 so that the activity does not resu lt in endangerment of USDWs.

EPA believes that the UIC Program, under the authority of the SDWA, provides a strong framework for regulating injecti on of CO2 for GS and adds that the GS regulation tailors the UIC requirements to address the unique issues as sociated with large-scale GS including large injection volumes, the relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurities in captured CO2, and its mobility within subsurface geologic

formations.

Letter ID: 0213 Comment ID: 22925 Letter Lines: 188 to 209

Comment Code: 2126 1.6.1.2 Comments opposing injection into deep saline

Comment: AMWA is also concerned about using salin e aquifers for carbon sequestration. In a climate-stressed and ultimately water-s tressed world, it is quite possible that these aquifers will be used as dr inking water supplies in the near future. For example, EPA states in the rule proposal that deep saline a quifers that have >10,000 TDS will account for 88% of geose questration sites. Many of these aquifers may actually be targeted for water supply.

The experience of drinking water system s in Florida and other areas has

demonstrated that TDS measurements in USDWs are a moving target. The upper Floridan aquifer is curren tly about 8000 mg/L TDS. Ho wever, in pumping this already brackish aquifer, the upwelling of more saline waters from below is occurring. In addition, some utilities are considering pumping from deeper wells with a higher salinity for drinking water supply and using reverse osmosis to

treat for TDS.

As the protection of current and future drinking water supplies is paramount, AMWA suggests that when there are competi ng uses in an aquifer, the needs of the aquifer for drinking water supply should ta ke precedence over other municipal or

industrial uses and the risk of unintended impacts on pot able water supplies is

7unacceptable. AMWA suggests that EPA re quire a more rigorous scientific evaluation in the final rule about how pot ential risk to potable aquifers will

be avoided in the site ch aracterization for a CO2 ge osequestration project.

Individual Response: EPA clarifies that the final rule requir es the Director to notify the director of the state public water system supervision program (PWSS) when a draft permit becomes available for public comment. EPA expects that the PWSS director will provide input to the Director regarding competing needs for water resources and whether to grant a permit.

The Agency acknowledges commenter concerns a bout water resources and future water resource availability. However, modifying the definition of a USDW is outside the scope of the GS rulemaking. USDWs are defined as aquifers currently being used as sources of drinking water or those capable of supplying a public water system and they have a total dissolved solids (TDS) content of 10,000 milligrams per liter or less (§144.3).

The primary goal of the UIC Program under the SDWA is to protect USDWs in order to ensure a reliable supply of drinking water for the Amer ican public. The GS rule, as part of the UIC program regulations, continues the program’s stat utory mandate of ensuring the protection of USDWs. The permitting, siting, construction, opera tion, monitoring, and post-injection site care requirements in the GS rule built on a long-standi ng protective regulatory fr amework, tailored to the unique characteri stics of CO2 GS.

EPA clarifies that a state’s Cla ss VI primacy program may be more stringent then the federal requirements. For example, a state has the disc retion to ban GS projects from taking place in specific formations or other areas where there ar e water resource issues. EPA believes that state permitting authorities are in the best position to make determina tions about the appropriateness of a particular site based on all available in formation, including drinking water supply needs.

Letter ID: 0213 Comment ID: 22926 Letter Lines: 211 to 214

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

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

Comment: Drinking water utilities must be consu lted during the review of any CO2 sequestration permit application. AMWA recomm ends that as part of the process, all drinking water utilities that draw from an aquifer in the area of review (AoR) of a potential CO2 sequestration proj ect should be informed and consulted.

Individual Response: As part of the UIC permit review process in 40 CFR 124, the UIC program Director must notify certa in stakeholders of any public h earings and the av ailability of the draft permit. EPA has added a requirement at §124.10(c)(1)(xi) that state and local oil and gas regulatory agencies and state agencies re gulating mineral exploration and recovery, the PWSS program director, and all agen cies that oversee injection wells in the state must be notified as part of the public notice pr ocess for a Class VI permit.

8In addition, the existing public participation requirements for UIC permits at 40 CFR 124.10(c)(1)(x)(A) require not ification "to any unit of local g overnment having jurisdiction over the area where the facility is proposed to be located." EPA believes these requirements address

the commenter's concerns.

Letter ID: 0213 Comment ID: 22927 Letter Lines: 215 to 218

Comment Code: 3500 2.2.3 Area of Review Reevaluation (seeking comment)

Comment Code: 5560 2.10.3 Enhancing the public particip ation process (seeking comment)

Comment: In addition, AMWA recommends that local drinking water utilitie s be included in the AoR review process, as drinking wate r or potential drinking water sources may become threatened due to a change in plume direction or behavior. Public involvement also needs to be a mandatory part of the AoR reevaluation process.

Individual Response: EPA agrees that coordination between GS project owners or operators, program Directors, drinking water utilities that may be affected by GS activities, and the public is important. EPA encourages GS project operators and permitting authorities to use the Internet

and other available tools to e xplain potential GS projects, describe the technology, and post information on the latest developments, including schedules for hearings, briefings, and other opportunities for involvement. EPA has added a re quirement at §124.10(c)(1)( xi) that state and local oil and gas regulatory agencies and stat e agencies regulating mineral exploration and recovery, the PWSS program director, and all agenci es that oversee inject ion wells in the state must be notified as part of the public notice process for a Class VI permit.

EPA encourages permitting authorities to notify and involve as many stak eholders as possible including drinking water organizations and lo cal water utilities. §124.10( c)(1)(x)(A) requires notification "to any unit of local government having jurisdicti on over the area where the facility is proposed to be located; and (B) to each Stat e agency having any author ity under State law with respect to the construction or operation of such facility."

EPA anticipates that drinking water associations a nd local water utilities w ill express interest in and be notified of draft permits and public he arings as required under §124.10(c)(1)(ix) and 40 CFR Part 25.5 (where EPA is providing public information) which requires the permitting authority to notify all interested parties.

EPA notes that public notice is required if the Director dete rmines that a major permit modification is necessary as a result of an AoR re evaluation or other indication that the plume is moving in a manner other than predicted. See §144.39(a)(5).

Letter ID: 0213 Comment ID: 22928 Letter Lines: 220 to 226

Comment Code: 2100 1.6 Target Geologic Formations for GS

9Comment: Unintended consequences: There have b een unintended consequences in the deployment of municipal disposal wells in Florida, and AMWA cautions EPA to be very cautious in allowing for carbon sequest ration wells to be drilled in areas that are not protected by a confining layer of bedrock. For example, AMWA

believes that EPA should exclude certain formations such as basalt, shale, fractured karst and coal bed seams from Class VI CO2 injection until more research about the appropriateness injection into these formations completed.

Individual Response: EPA clarifies that the final GS rule does not categorically preclude injection of CO2 into any non-USDW formation type s. The purpose of the GS rule is to ensure protection of USDWs from endangerment, and th e rule requires that owners or operators demonstrate that wells are sited in suitable sy stems with geologic formations to receive and confine injected CO2, required at §146.83 of the GS rule. Specifically, EPA clarifies that §146.83(a) requires the owner or operator to demonstr ate the presence of a confining layer free

of transmissive faults or fractur es and of sufficient extent to contain the injected carbon dioxide and any displaced formation fluids; and that the injection zone is of sufficient areal extent, thickness, porosity, and permeability to receiv e the total anticipated volume of the carbon

dioxide stream.

The Class VI siting, well construction and opera tion, monitoring and testing, and post-injection site care and site closure requirements are designed to ensure that inject ed CO2 remains within the target formation. If an owner or operator can demonstrate to the Dire ctor's satisfaction that GS in coal seams, basalts, salt domes, or shal es can be accomplished in a manner that protects USDWs and meets all of the requirements of the GS rule, the project may be permitted as a Class

VI well.

Regarding unintended consequences related to muni cipal disposal wells in Florida, EPA clarifies that GS is quite different from the injection of wastewater in Florida. An owner or operator seeking to characterize a site for GS (pursuant to the requirements at §146.82) and identify both injection formations and suitable confining units per §146.83 may not be able to meet the requirements and ensure protection of USDWs due to the nature of karst formations/geology. In addition, the computational modeling required to delineate the AoR fo r a GS project would likely predict inappropriate buoyant flow and eliminate such formati ons as potential GS sites.

Letter ID: 0213 Comment ID: 22929 Letter Lines: 228 to 234

Comment Code: 2300 1.7 Comments on the Alternatives Considered

Comment: Regulatory alternative: EPA’s proposed Alternative 3 for permitting CO2 geosequestration appears to be the best approach in that it would allow for projects to move forward. AMWA supports th is approach because it provides the permitting authority with discretion to require additional information from owner/operators applying for a permit and to make case-by-case permitting decisions. This is important as water chemistry and subsurface geology differ widely across the country.

10Individual Response: EPA agrees with the commenters that Regulatory Alternative 3 is appropriate. The technical requirements in Alte rnative 3 (and the final GS rule) build upon the long-standing UIC regulatory framework for deep we lls and are appropriately tailored to address the unique nature of full-scale CO2 GS, includi ng the volumes of CO2 to be injected, the buoyant and mobile nature of the injectate, and its corrosivity in the presence of water.

Even though the Agency did not choose Alternatives 1 or 2, EP A agrees that flexibility is important to accommodate the varied conditions that may be encountered at GS sites while ensuring the protection of USDWs. The final GS regulation gives the Director discretion to set permit criteria that are appropr iate to site-specific conditions and to require submission of additional information when necessary. The regul ation provides flexibility for selection of appropriate sites and target formations ( under §146.82), well construc tion specifics (under §146.86), and testing and monitoring regimes ( under §146.90), provided the owner or operator can demonstrate that the injection and storag e will not endanger USDWs and that minimum requirements for the site are met.

Letter ID: 0213 Comment ID: 22930 Letter Lines: 236 to 240

Comment Code: 2020 1.5.1 Support Class VI designation

Comment: Class VI wells: AMWA agrees with EPA’s proposal to have CO2 geosequestration wells permitted under a new UIC category -- Cl ass VI -- as this is a new type of injection well. However, as there is limited modeling or monitoring data specific to UIC of CO2 available, this da ta gathering and modeling must occur.

AMWA has additional comments a bout research needs below.

Individual Response: EPA agrees that tailored requirements for Class VI wells are necessary to address the unique nature of in jecting large volumes of CO2 a nd to ensure that USDWs are protected from endangerment. The GS rule c ontains tailored requirements for the permitting, geologic site characterization, AoR and corre ctive action, well construction, operation, mechanical integrity testing, monitoring, well plu gging, post-injection site care, and site closure of GS wells that directly addre ss issues unique to the nature of large-scale CO2 injection for GS.

EPA adds that it continues to monitor resear ch being conducted on GS and will use this to inform its adaptive rulemaking approach. EPA plans, every six years, to collect and review data on GS projects to determine whether the approp riate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are approp riate or necessary.

Letter ID: 0213 Comment ID: 22931 Letter Lines: 242 to 251

Comment Code: 3820 2.3.1 Well construction procedures

Comment: Aspects of permitting process:

11- Well construction o EPA’s proposal requires that materials that meet or exceed industry standards must be compatible with injected CO2 and "are designed for the life of the well". As the CO2 may be stored underground indefinitely, are concretes and other well materials designed to last forever under the chemical and geological conditions expected in a carbon sequestration well? AMWA requests that EPA and DOE perform additional

research and data collection in this area.

Individual Response: EPA clarifies that the rule requires th at all well materials be compatible with fluids with which they may come in contact and be of sufficient structural strength to last the life of the sequestration pr oject. GS projects ar e anticipated to have long life spans in comparison to other types of deep injection we lls. Not only must Class VI wells be able to function safely and properly over the lifespan of the GS project, but they must be constructed such that USDWs remain protected after well plugging. The requirements at §146.86 will ensure that the well can maintain integrity throughout the proposed life span of the project, including after the injection well is pl ugged and through the post- injection site care period and beyond (73 FR 43510). While the risk profile of a GS site will decrease following cessation of injection,

EPA believes that Class VI wells must be desi gned to protect USDWs from endangerment for the life of the project. Furthermore, rigorous cas ing and cementing help ensure that the Class VI

well will not serve as a conduit for the movement of fluids associated with future injection operations.

Letter ID: 0213 Comment ID: 22932 Letter Lines: 253 to 254

Comment Code: 4546 2.5.2.2 MIT frequency (seeking comment)

Comment: - Mechanical integrity testing o AMWA supports EPA’s proposal for mechanical in tegrity testing every ye ar. This safeguard is necessary to protect dr inking water supplies, as wells will be drilled thro ugh USDWs to reach

confined bedrock for sequestration wells.

Individual Response: EPA agrees that annual external mechanical integrity testing is justifiable for the protection of USDWs from endangerment, given the unique nature of CO2 GS relative to other injection operations, includ ing the potential for corrosion of the injection well components (e.g., steel casing and cement) and the buoyant natu re of the injected CO2. EPA is finalizing regulations that require annual external MITs at §146.89(c).

Letter ID: 0213 Comment ID: 22933 Letter Lines: 256 to 264

Comment Code: 1510 1.2.2.3 Need for additional study

Comment: Research must be comprehensive and must continue to increase our limited understanding of this technology. Class VI is a new unique type of well category

that needs to have theo retical research (i.e., m odeling) and monitoring

12performed, as well as other data ga thered, to better understand how CO2 sequestration will affect groundwater a nd the subsurface geology. The research must include a combination of good theore tical work and sound observational work as we are entering uncharted territory . While CO2 has been used for gas extraction, under geosequestration, CO2 w ould be put in the ground permanently. As a result, AMWA has the following recommendations for research:

Individual Response: As described above, EPA agrees that continued research in all GS associated fields will be integral to development of GS technology.

Letter ID: 0213 Comment ID: 22934 Letter Lines: 266 to 271

Comment Code: 1510 1.2.2.3 Need for additional study

Comment Code: 1600 1.3 Risk Associated with CO2 GS

Comment: o Before any CO2 geosequestration projects are fully deployed, more research is needed to allow EPA and/or DOE to develop a risk assessment for the technology, taking into account risks to USDWs.

o The effectiveness of available risk mana gement methods must be demonstrated. This is also recommended by the IPCC in its Summary for Policymakers.

Individual Response: As described above, EPA agrees that continued research in all GS

associated fields will be inte gral to development of GS t echnology. EPA is using an adaptive approach to regulating GS under the UIC Program. Even after fina lization of the GS regulation, the Agency plans to collect and review data every six years on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are a ppropriate or necessary.

EPA believes that the GS rule requirements are tailored to address the unique challenges posed by GS and the potential risks associated with th e long-term injection of CO2. These requirements include the tailored AoR delineation process pe r §146.84, monitoring that is appropriate to GS projects per §146.90, and extended po st-injection site care per §146.93.

Letter ID: 0213 Comment ID: 22935 Letter Lines: 273 to 276

Comment Code: 3300 2.2.1 Delineating the AoR/M odeling CO2 movement

Comment: o Groundwater modeling is improving and variab le density flow models for deeper aquifers can be used with reasonable accu racy for understanding subsurface flow and quality. However these models must ta ke variables such as heat transport

into account to better translate to a CO2 geosequestration scenario.

Individual Response: EPA agrees that heat transport may be an important process in modeling of the AoR. The GS regulation stipulates, at 146. 84(a), that the physical and chemical properties

13of all phases of the injected CO2 stream must be accounted for in the model. Heat transport is one of several processes that describe the geologic site, the in jection scenario, and the fluids present, all of which are the foundation fo r the multiphase, AoR model development.

Letter ID: 0213 Comment ID: 22936 Letter Lines: 278 to 280

Comment Code: 3130 2.1.3 Comments that operators s hould submit more (or different) geologic data than proposed

Comment: o Data can and should be gathered immediat ely and more core analysis should be required in the permitting process -- speci fically for key formations and for water/rock/gas interaction.

Individual Response: The Agency agrees and believes that the site characterization requirements at §146.82 are essential to proper s iting of a GS well and are the foundation for a detailed understanding of the local and regiona l geology. Collecting and evaluating geochemical data in and around the CO2 injection zone, as re quired in §146.82(a)(6), serves several purposes. This baseline geochemical data can help predic t geochemical reactions between the injectate, reservoir geology, and formation fluids. Such reac tions can lead to dissolution and precipitation of minerals which affect formation porosity, which in turn can affect required injection pressure (Sminchak and Gupta, 2002) and transport of fl uid within the formation. While the confining layer is the primary barrier to CO2 movement into a USDW, multiple barriers are important and changes in injection pressure and fluid movement may compromise those barriers. An increase in injection pressure due to reduced porosity, in particular, can lead to fracturing of the confining layer and potentially allow fluid movement outside of the injec tion zone. Losses in injectivity because of geochemical reactions may also re quire additional injection wells and further penetrations in the confini ng layer that can become path ways for fluid migration.

Letter ID: 0213 Comment ID: 22937 Letter Lines: 282 to 285

Comment Code: 4660 2.6.6 Geochemical monitoring

Comment: o Rock cores and thorough geochemical anal ysis of geosequestration should happen

even before the AoR. Advances in re search and subsurface modeling make it possible to analyze the interaction between rock formations and CO2. Performing these analyses early on could potentia lly prevent unintended consequences.

Individual Response: EPA agrees and believes that the ba seline geochemical data required at §146.82(a)(6) will provide information on predicting potential interactions between rocks and CO2 as the commenter suggests, and also expects that this information will inform the development and approval of a site-s pecific testing and monitoring plan.

EPA is developing guidance on testing and mon itoring to assist owne rs or operators and Directors in evaluating requi rements under §146.90, including pr oposed monitoring plans. The guidance describes available technologies a nd recommended approaches for implementing a

14testing and monitoring plan, including pre-ope rational geophysical l ogging and testing of injection wells, MITs, injecti on well testing during operation, groundwater quality monitoring, tracking the CO2 plume and pressure front, a nd soil gas and surface air monitoring which may be required by the UIC Director for specific GS projects. Th e guidance can be found on EPA’s website at http://water.epa.gov/type/groundwater/u ic/wells_sequestration.cfm. In addition, in January 2009, DOE published a best practices ma nual entitled "Monitoring, Verification, and Accounting of CO2 Stored in Deep Geol ogic Formations" (DOE /NETL-311/081508); this

manual is included in the docke t for the final GS rule.

Letter ID: 0213 Comment ID: 22938 Letter Lines: 287 to 288

Comment Code: 1300 1.1.2.3 Comments on other aspects of CCS (capture, transport)

Comment Code: 1510 1.2.2.3 Need for additional study

Comment: o Potential ancillary effects of CCS -- such as pressure waves, which could move hundreds of miles and affect sequestra tion sites -- must be evaluated.

Individual Response: EPA agrees that continued research in all GS associated fields will be integral to development of GS technology. EPA notes that a study conducted by Lawrence Berkeley National Laboratory eval uated basin-scale hydrology and pressure changes that could occur as a result of GS; this st udy is described in EPA’s Notice of Data Availability and Request for Comment (74 FR 44802, see referen ces to Birkholzer et al. 2008b).

Letter ID: 0213 Comment ID: 22939 Letter Lines: 290 to 292

Comment Code: 1510 1.2.2.3 Need for additional study

Comment Code: 2100 1.6 Target Geologic Formations for GS

Comment: o Effects of CCS on saline aquifers ar e unknown. CO2 geosequestration modeling performed to-date has generally not consid ered this type of aquifer. This modeling must be conducted.

Individual Response: EPA acknowledges the commenter's c oncern about water resources and the protection of USDWs from endangerment. The Ag ency clarifies that the statutory mandate of the UIC Program—and the purpose of the GS rule —is to protect current and future underground sources of drinking water. Under SDWA au thority as implemented by the UIC Program regulations, the GS rule establishes comprehe nsive, rigorous requirements for permitting, siting, construction, operation, monitoring, and closur e of GS projects. The GS rule's siting requirements found at §146.82, along with other re quirements for construction, operation, testing and monitoring, and post-injection site care and site closure are designed to prevent the endangerment of USDWs in the vicinity of GS operations.

EPA disagrees that insufficient modeling and ri sk evaluation have been conducted to support the GS rulemaking. To develop the GS rule, EPA considered laboratory, modeling, and field research, which included data from saline aqui fers. In addition, the Agency is involved in

15collecting and analyzing GS project data and information from a variety of sources. Most notably, EPA has evaluated and written permits and reviewed operational data and information associated with the regional carbon sequestrati on partnership pilot projects funded by DOE and coordinated through the Nati onal Energy Technology Laboratory (NETL), and several international projects.

EPA agrees that continued research in all GS asso ciated fields will be integral to development of GS technology. EPA is aware of research by ot her federal agencies, industry, international parties, and academia related to GS, including proj ects that address many of the topics suggested by commenters. EPA published a Notice of Da ta Availability (NODA) and Request for Comment on August 31, 2009 (74 FR 44802), in whic h the Agency described the results of research at three DOE partnership sites (in Es catawpa, Mississippi; the Aneth Field in Paradox Basin, southeast Utah; and the Pump Canyon Site , New Mexico). In the NODA and Request for Comment, EPA also described two studies by the Lawrence Berkeley National Laboratory on the potential effects of CO2 injection on ground wate r and surrounding formations to determine the potential for impacts on USDWs and human health in the event that a GS project is not properly sited, operated, or managed.

EPA acknowledges that there may be risks associat ed with GS in certain formation types. For this reason, the Agency is using an adaptive appr oach to regulate GS injection. EPA will collect and review project data on early GS projects, including those that inject into various formation types, to determine whether the appropriate am ount and types of information and documentation are being collected. EPA plans, every six years, to collect and review data on GS projects to determine whether the appropriate amount a nd types of information and appropriate documentation are being collected, and to determ ine if modifications to the requirements are appropriate or necessary.

Letter ID: 0213 Comment ID: 22940 Letter Lines: 299 to 318

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

Comment: - 73 FR 43502 -EPA seeks comment on the a pproach to grandfat her construction requirements at the Director’s discreti on for existing Class I, Class II, and Class V wells seeking to convert to Class VI wells , and whether additional construction requirements would be necessa ry to prevent endangerment to USDWs from the GS of CO2. Additionally, EPA s eeks comment on how the grandfathering approach for existing wells may affect co mpliance with the requirements in this proposal.

Response: AMWA recommends that any well bei ng considered for injection of CO2 be required to meet the same standards as detailed in EPA’s rule for class VIwells. For example, the wells must be constructed with the same corrosionresistant materials required under the rule. AMWA is new to the details of the UIC program and is concerne d that wells constructed under Class I, II and V

16requirements may not have the same prot ective measures required in EPA’s proposed regulation, such as the down-hole shutoff valve. AMWA recommends that if EPA proceeds with allowing for wells al ready constructed to be grandfathered

and converted to Class VI wells that the owner/operator of the well must conclusively demonstrate, through mode ling, monitoring and other appropriate data, that the well can be operated in co mpliance with all requirements of the

final rule.

Individual Response: EPA agrees that a cautious approach to grandfathering is appropriate, particularly given that the convert ed well will be used for a substa ntially different process, which involves increased reservoir pre ssures associated with large volumes of stored CO2 and the corrosivity of CO2 in the presence of water. Th e final GS rule provides for the construction of these wells to be grandfathered (per 146.81(c)). EPA has included a requirement in the final GS rule that owners or operators seeking to c onvert existing wells for long term storage must

demonstrate to the Director that the grandfathered wells were engi neered and constructed to meet the requirements at §146.86(a) and ensure prot ection of USDWs, in lieu of requirements at §146.86(b) and §146.87(a). EPA clarifies that only the construction requirements are grandfathered and that all ot her Class VI requirements (reporting, monitoring, mechanical integrity testing, etc.) must be met following a determination under §146.81(c). EPA expects that Directors review and consider many of the factor s the commenter mentions, such as the materials used and the ability of the well to be tested fo r, and maintain, mechanical integrity during CO2 injection when making their determina tion that §146.81(c) has been met.

After evaluating the risk s and benefits of down-hole shut-off systems and considering additional research, EPA will not require automatic down-ho le shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2), re quires that owners or operato rs of onshore Class VI wells

install automatic surface shut-off devices. The ru le affords Director's discretion to mandate

automatic down-hole shut-off devices in onshore situ ations that may warrant their use. However, the Agency believes that offshore Class VI we lls present unique construction and operational conditions, including isolation from shorelines and the need to c onstruct wells th rough the water column and the subsurface, which may delay res ponse time in the event of well difficulties. The rule requires, at §146.88(e)(3), that owners or oper ators of offshore wells w ithin State territorial waters install automatic down-hole shut-off system s. EPA believes that these requirements at §146.88(e) ensure that proper precautions are take n to prevent subsurface fluid movement and ensure protection of USDWs.

Letter ID: 0213 Comment ID: 22941 Letter Lines: 320 to 325

Comment Code: 1510 1.2.2.3 Need for additional study

Comment Code: 2166 1.6.3.2 Comments opposing injection into unmineable coal seams

Comment: - 73 FR 43503 - EPA requests comment on prohi biting injection into unmineable coal seam formations if they are above the lowermost USDW.

Response: AMWA opposes the injection of CO 2 into coal seams in general and as

17stated earlier recommends that EPA a nd DOE conduct additional research to determine the impacts of CO2 storage on co al seams. Furthermore, AMWA opposes

Individual Response: As described above, the final GS ru le does not preclude injection into unmineable coal seams (or any formation type) provided owners or operators can demonstrate that GS can be performed in a manner th at protects USDWs from endangerment.

EPA recognizes that GS in unmineable coal seam s has been the subject of less research than saline formations or depleted oil and gas re servoirs. EPA continues to follow existing DOE projects and plans, every six years, to collect and review data on GS projects to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modificatio ns to the requirements are appropriate or

necessary.

Letter ID: 0213 Comment ID: 22942 Letter Lines: 325 to 339

Comment Code: 4322 2.4.4.1.1 Comments in favor of requiri ng injection below the lowermost

USDW

Comment: determine the impacts of CO2 storage on co al seams. Furthermore, AMWA opposes the injection into any formation above th e lowermost existing or potential USDW and recommends that EPA only allow for the injection of CO2 into formations below the lowermost existing or poten tial USDW. Congress intended the UIC program to protect sources and potential sources of drinking water from contamination: "Underground injection enda ngers drinking water sources if such injection may result in the presence in underground water which supplies or can reasonably be expected to supply any public water system of any contaminant, and if the presence of such contaminant may result in such system’s not complying with any national primary drinking water regulation or may otherwise adversely affect the health of persons." SDWA § 1421(d)(2); 42 U.S.C. § 300h(d)(2).

AMWA believes that allowing the injection of CO2 above a USDW would endanger the USDW by providing a pathway for CO2 to contaminate a drinking water source, especially if a well was cons tructed through a CO2 plume.

Individual Response: EPA agrees that protecting USDWs from endangerment must be a top priority. The Agency believes that there are limited circumstances where injection above the lowermost USDW can be performed in a manner that protects USDWs, as long as appropriate protections are in place. The final GS rule at §146.95 establishes a process by which owners or operators can seek a waiver of the Class VI in jection depth requirement s for injection into nonUSDW formations above and/or between USDWs. The waiver approach requires the submission of extensive, site-specific information (in conj unction with the permit appl ication submission) to demonstrate that injection of CO2 into a non-US DW that is above or between USDWs can be done in a manner that is protective of USDWs. It establishes: 1) requirements specifying information that owners or operators must subm it, and Directors must consider, in consultation

18with PWSS Directors; 2) procedur es for public notice of a waiver application a nd for DirectorRegional Administrator communicat ion; 3) the waiver issuance process; and, 4) additional requirements that apply to owners or operators of Class VI wells granted a waiver of the injection depth requirements to ensure USDW protection above and below the injection zone.

EPA believes that the requirements at §146.95 w ill ensure USDW protection while providing flexibility to UIC Program Dir ectors and owners or operators who undertake CO2 injection for GS. The Agency believes this approach: 1) responds to concerns a bout local and regional geologic storage capacity limitations imposed by the proposed injection depth requirements; 2) allows for a more site-specific assessment of injection depth for GS projects; 3) accommodates injection into different formation types; 4) allo ws for injection of CO2 for GS into non-USDWs above and/or between USDWs when appropriate and where it can be demonstrated that USDWs will be protected; and 5) responds to concerns about the use of aquifer exemptions for GS. Finally, EPA’s approach to addressing injecti on depth variability thr ough a waiver process responds to concerns about future drinking water resource availability and the need to ensure that high quality water remains available in sufficien t quantities to supply dr inking water needs. For additional information on the waiver approach, pleas e see the final rule and preamble, as well as EPA's responses to comments on the Notice of Data Availability and Request for Comment.

Letter ID: 0213 Comment ID: 22943 Letter Lines: 341 to 357

Comment Code: 3530 2.2.3.1 AoR reevaluation fre quency (seeking comment)

Comment Code: 3560 2.2.3.2 Conditions that merit reevalua tion of the AoR (seeking comment)

Comment: - 73 FR 43507 -EPA seeks comment on requiring the reevaluation of the site AoR on a periodic basis, under what conditi ons the AoR should be reevaluated, and the appropriateness of a 10 year minimu m fixed frequency for AoR reevaluation.

Response: As carbon sequestration is an emerging technology that has not yet been tested on a large scale in the U.S., AMWA believes at this time that a tenyear minimum frequency for AoR evaluation is not sufficient. AMWA recommends

instead that the AoR be reevaluated a nnually for the first ten years of the project and then every five years for the remaining operating period of the project.

AMWA also recommends that the final rule include criteria to trigger a shorter review period at earlier intervals should monitoring detect a sudden change in CO2 plume movement, size or pressure. In addition, AMWA recommends that local drinking water utilities be included in the AoR review process, as existing or potential drinking water sources could beco me threatened due to a change in plume direction or behavior. Public invol vement also needs to be a mandatory

Individual Response: EPA agrees with commenters that reevaluations of the AoR every ten years may not be sufficient to appropriately model plume and pressure front movement, establish conditions for corrective action, and ensure prot ection of USDWs from endangerment. For these reasons, the Agency changed the minimum freq uency for the AoR reevaluation at §146.84(e)

19from 10 years to at least every 5 years in the final GS rule. EPA belie ves that this revised frequency addresses commenters' concerns about the inherent uncertainties in modeling CO2 movement, the emerging nature of GS technology, risk-based targeting of monitoring activities, and the unique nature of CO2 GS.

EPA agrees that other aspects about a GS project may trigger the need for an AoR reevaluation, and adds that the AoR and corrective action plan must also specify the site-specific monitoring and operational conditions that warrant reevaluation, as spec ified in §146.84(b)(2)(ii). EPA agrees that site-specific information is an important factor in determining when AoR reevaluations are appropriate, and expects that th e owner or operator's and Director's combined knowledge of the local geologic conditions will be a critical element in developing plans that protect USDWs from endangerment. In addition, the Director has discretion to require more frequent AoR reevaluation if he or she has reason to believe, based on site-specific information, that a five-year reevaluation schedule is not sufficiently protective of USDWs.

Regarding the suggestion that lo cal drinking water utilities be included in the AoR review process, EPA added text to §144.39(a)(5) that pe rmit modifications woul d be required if the

Director determines that a modification is nece ssary based on an AoR reevaluation, amendments to any of the project plans, or a review of th e testing and monitoring results. EPA encourages permitting authorities to notify and involve as many stakeholders as possible about permit modifications, including dri nking water organizations and local water utilities.

Letter ID: 0213 Comment ID: 22944 Letter Lines: 357 to 358

Comment Code: 3500 2.2.3 Area of Review Reevaluation (seeking comment)

Comment Code: 5560 2.10.3 Enhancing the public particip ation process (seeking comment)

Comment: plume direction or behavior. Public invol vement also needs to be a mandatory part of the AoR reevaluation process.

Individual Response: EPA notes that, public notice is required if the Director determines that a major permit modification is necessary as a re sult of an AoR reevalua tion. See §144.39(a)(5).

Letter ID: 0213 Comment ID: 22945 Letter Lines: 360 to 367

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

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

Comment: - 73 FR 43510 -EPA seeks comment regard ing requirements for degradationresistant well construction materials, such as acid-resistant cements and corrosion resistant casing.

Response: AMWA agrees that cement and other

20materials used for carbon sequestration we ll construction must be resistant to corrosion and other potential chemical react ions in the subsurface. As stated

earlier AMWA also recommends that addi tional materials resear ch be performed.

Individual Response: EPA agrees that the use of non-co mpatible materials can result in degradation and failure of the well and could ultimately endanger a USDW. Under §146.86(b)(1), casings and cement and other material s used must have sufficient strength and be designed for the life of the sequestration project. Further, materials must meet standards listed in the rule and be compatible with fluids with wh ich the materials may be expected to come into contact. Therefore, some well materials may need to be acid-resistant and some may not if they

do not come in contact with the CO2 stream or other corrosive fluids and if approved by the

Director.

EPA continues to actively monitor ongoing resear ch on GS and related subtopics. The Agency actively tracks more than two dozen DOE p ilot projects, which ar e providing practical knowledge and field experience in the early deployment of GS injection wells. The Agency discussed three specific projects in the Notice of Data Availability and Request for Comment: the Aneth field ER project; the Escatawpa, Mi ssissippi saline basin project; and the Pump Canyon Unmineable coal seam project. EPA has also reviewed information from several international large-scale commercial GS operations.

EPA plans to, every six years, co llect and review project data on early GS projects, including site characterization, operational, monitoring, and modeling data, to determine whether the appropriate amount and types of information a nd appropriate documentation are being collected,

and to determine if modifications to the re quirements are appropr iate or necessary.

Letter ID: 0213 Comment ID: 22946 Letter Lines: 369 to 374

Comment Code: 4200 2.4.2 Down-hole shut-off valves in GS wells (seeking comment)

Comment: - 73 FR 435110 -EPA seeks comment on the merits of requiring down-hole shut-off valves in geosequestration wells.

Response: AMWA supports requiring down-hole shut-off valves in all geosequestration wells as these valves c ould provide a line of defense against

contamination of USDW in the event of a defective inje ction process.

Individual Response: After evaluating the risks and benefi ts of down-hole shut-off systems and considering additional research, EPA will not re quire automatic down-hole shut-off devices for onshore Class VI wells since it is not necessary in all cases to ensure protection of USDWs from endangerment. Instead, the final rule, at §146.88(e)(2 ), requires that owne rs or operators of

onshore Class VI wells install automatic surface shut-off devices. The rule affords Director's

discretion to mandate automatic down-hole shut -off devices in onshore situations that may warrant their use. However, the Agency believ es that offshore Class VI wells present unique construction and operational conditi ons, including isolation from shorelines and the need to construct wells through the water column and the subsurface, which may delay response time in

21the event of well difficulties. Th e rule requires, at §146.88(e)(3), that owners or operators of

offshore wells within State territorial waters install automatic down-hole shut-off systems. EPA believes that these requirements at §146.88(e) ensure that proper precautions are taken to prevent subsurface fluid movement and ensure protection of USDWs.

Letter ID: 0213 Comment ID: 22947 Letter Lines: 376 to 397

Comment Code: 4322 2.4.4.1.1 Comments in favor of requiri ng injection below the lowermost

USDW

Comment: - 73 FR 43512 - EPA requests comment on whether CO2 injection should be allowed into an injection zone above the lowermos t USDW, when the Director determines that geologic conditions exist that will pr event fluid movement into adjacent

USDWs.

Response: AMWA opposes the injection into any formation above the lowermost existing or potential USDW and recommends that EPA take a phased approach and prohibit the construction of CO2 sequestra tion wells in aquifers currently used for drinking water supply or expected to be used in the future, until more is known about the risks of CO2 sequestration to USDWs as a result of the effects and dynamics of the fluid in the subsurf ace. Congress intended the UIC program to protect sources and potential sources of drinking water from contamination: "Underground injection endangers drinking water sources if such injection may result in the presence in underground wa ter which supplies or can reasonably be expected to supply any public water syst em of any contaminant, and if the presence of such contaminant may result in such system’s not complying with any national primary drinking water regulation or may otherwise adversely affect the health of persons." SDWA § 1421(d)(2); 42 U.S.C. § 300h(d)(2).

AMWA believes that allowing the injection of CO2 above a USDW would endanger the USDW by providing a pathway for CO2 to contaminate a drinking water source, especially if a well was cons tructed through a CO2 plume.

Individual Response: EPA agrees that protecting USDWs from endangerment must be a top priority. The Agency believes that there are limited circumstances where injection above the lowermost USDW can be performed in a manner that protects USDWs, as long as appropriate protections are in place. The final GS rule at §146.95 establishes a process by which owners or operators can seek a waiver of the Class VI in jection depth requirement s for injection into nonUSDW formations above and/or between USDWs. The waiver approach requires the submission of extensive, site-specific information (in conj unction with the permit appl ication submission) to demonstrate that injection of CO2 into a non-US DW that is above or between USDWs can be done in a manner that is protective of USDWs. It establishes: 1) requirements specifying information that owners or operators must subm it, and Directors must consider, in consultation with PWSS Directors; 2) procedur es for public notice of a waiver application a nd for DirectorRegional Administrator communicat ion; 3) the waiver issuance process; and, 4) additional requirements that apply to owners or operators of Class VI wells granted a waiver of the

22injection depth requirements to ensure USDW protection above and below the injection zone.

EPA believes that the requirements at §146.95 w ill ensure USDW protection while providing flexibility to UIC Program Dir ectors and owners or operators who undertake CO2 injection for GS. The Agency believes this approach: 1) responds to concerns a bout local and regional geologic storage capacity limitations imposed by the proposed injection depth requirements; 2) allows for a more site-specific assessment of injection depth for GS projects; 3) accommodates injection into different formation types; 4) allo ws for injection of CO2 for GS into non-USDWs above and/or between USDWs when appropriate and where it can be demonstrated that USDWs will be protected; and 5) responds to concerns about the use of aquifer exemptions for GS. Finally, EPA’s approach to addressing injecti on depth variability thr ough a waiver process responds to concerns about future drinking water resource availability and the need to ensure that high quality water remains available in sufficien t quantities to supply dr inking water needs. For additional information on the waiver approach, pleas e see the final rule and preamble, as well as EPA's responses to comments on the Notice of Data Availability and Request for Comment.

Letter ID: 0213 Comment ID: 22948 Letter Lines: 399 to 407

Comment Code: 4470 2.4.4.4.2 Comments opposing aquifer exemptions in all cases

Comment: - 73 FR 43512 - EPA is also requesting co mment on whether aquifer exemptions should be allowed for the purpose of Class VI injection, and under what conditions should such aquife r exemptions be approved.

Response: AMWA does not believe it is pr udent to allow for aquifer exemptions for the purpose of Class VI injection as saline aquifers not currently used for

USDWs could be considered viable drinking water suppl y in a water-stressed environment. AMWA strongly believes that the use of an aquifer for drinking water supply should take precedence over a ll other municipal or industrial uses.

Individual Response: EPA believes that there are limited circumstances where aquifer exemptions for GS may be warranted, and the final GS rule allows for the expansion of the areal extent of existing aquifer exemptions for Cl ass II EOR/EGR wells tran sitioning to Class VI injection for GS pursuant to requirements at §§146.4 and 144.7(d). Class VI owners or operators granted expansions of existing Class II EOR/EGR aquifer exemptions for GS projects must meet all of the tailored requirements for GS wells in the final GS rule.

If an owner or operator applies for a Class VI permit to inject CO2 into a previously exempted aquifer (non-USDW) that is lo cated above and/or between USDW s, the permit applicant must also apply for a waiver of the injection depth re quirements pursuant to §146.95 to ensure that if a waiver is granted, USDWs above and below the inje ction zone are protected from endangerment.

The Agency developed the waiver process to ad dress comments and conc erns about current and future drinking water resources and the use of cl imate mitigation technology at appropriate sites. The aquifer exemption requirements in the final ru le provide flexibility and afford owners or operators an opportunity to asse ss and select a suitable GS si te while also preserving USDWs

23(i.e., formations/aquifers afforded SDWA protec tion). Class VI owners or operators granted expansions of existing Class II EOR/EGR aquifer exemptions for GS projects must meet all of the tailored requirements for GS wells in the fi nal GS rule. EPA agrees with the commenter's concerns about USDW preservation and protection and believes that , in most cases, the injection depth waiver is a more appropriate option than aquifer exemptions for Class VI injection, and that aquifer exemption expansions for GS should be granted in limited circumstances.

EPA agrees that future water resources needs ar e an important consideration, and believes that the injection depth waiver process at §146.95 res ponds to concerns about future drinking water resource availability and the need to ensure high quality water remains available in sufficient quantities to supply drinki ng water supply needs.

For additional information on the waiver approa ch and aquifer exemptions for Class VI wells, please see the final rule and pr eamble, as well as EPA's responses to comments on the Notice of Data Availability and Request for Comment.

Letter ID: 0213 Comment ID: 22949 Letter Lines: 409 to 428

Comment Code: 5700 2.12 Comments on the proposed durati on of Class VI permits (seeking comment)

Comment: - 73 FR 43523 -EPA proposes that Class VI in jection well permits would be issued for the operating life of the GS projec t including the post-injection site care period. EPA seeks comment on the merits of this approach.

Response: AMWA does not support issuing an operating permit fo r the life of the sequestration site. Instead, AMWA reco mmends issuing a lifetime operating permit for the coal plant, but with a separate and renewable permit for the operation of the geologic sequestration pr ocess. Drinking water treatment plants must notify state regulators of changes in ownership, management, or operations, and AMWA recommends that owner/operators of CCS sites be required to provide the same type of information to the Director in the event of changes. In addition, AMWA recommends that owner/operators be required to periodically reevaluate their injectate stream fo r any emerging contaminants, and remove them if required.

As CCS is a developing technology, AMWA re commends that EPA have a plan to update the regulation as addi tional information is gather ed through research and through data and observations collected from permitted sites. Having a permit renewal schedule built into the process will allow the Director to ensure that updates to the regulation ar e included in permit renewals. AMWA also suggests

Individual Response: The final rule maintains the lifetime permit provision and clarifies that the permit extends through the post-injection site car e period (144.36(a)). However, it also adds a requirement that the Director review each Class VI permit at least once every 5 years to determine whether it should be modified, re voked and reissued, terminated or a minor

24modification made as provided in §§144.39, 144.40, or 144.41. The Director’s review will be informed by the owners’ or operato rs’ iterative reev aluation of the project. Specifically, the final rule includes a requirement that the AoR be reev aluated at least every five years, and also requires owners or operators to review and update the AoR and corrective action plan, the testing and monitoring plan, and the emergency and reme dial response plan th roughout the life of the project (146.84(e), 146.90(j), and 146.94(d)). Owners or operators must review each plan and identify necessary amendments or demonstrate to the Director that no amendment is needed. In

no case can reviews occur less often than once ev ery five years. The iterative process and subsequent plan reevaluations ensure that time and resources are committed to the most critical aspects of the permit in preven ting endangerment to USDWs.

EPA adds that, as part of existing requirements at 40 CFR 144.39, the Director has the authority to revise the permit if project operations change or if the Director be lieves based on monitoring or operational data that the project may e ndanger USDWs. EPA has also added text to 144.39(a)(5) that permit modifications are required if the Director determines that a modification is necessary based on an AoR reevaluation, amendmen ts to any of the project plans, or a review of the testing and monitoring results. The Dir ector may also choose to require minor permit modifications under 40 CFR 144.41, depending on the ex tent of the plan amendment. All permit modifications, except minor modifications und er 40 CFR 144.41, require an opportunity for public comment on the portion of the permit that is being reopened pursuant to requirements

under 40 CFR Part 124.

EPA notes that monitoring of the injectate stre am is required under the monitoring and testing plan developed under 40 CFR 146.90; operators or owners must include injectate data in their semi-annual reports to the Director.

The Agency plans to collect and review data on GS projects every six years to determine whether the appropriate amount and types of information and appropriate documentation are being collected, and to determine if modifications to the requirements are a ppropriate or necessary.

EPA believes that these changes will address many comments in support of permit renewal. Additionally, the reevaluation pro cess could be aligned with i ssuance of other environmental permits associated with the facility, provided the minimum reevaluation frequency requirements

are met. EPA clarifies that it does not have th e authority under the SDWA (and associated UIC requirements) to alter permitting requirements issued under other environmental statutes for coal plants or any CO2 sources. The UIC program's aut hority is limited to the injection operation and ensuring that USDWs are protected from endangerment.

Letter ID: 0213 Comment ID: 22950 Letter Lines: 428 to 431

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

Comment: updates to the regulation ar e included in permit renewals. AMWA also suggests that the permit application process include a review of the site operations to see if any instances of unsafe operation or changes in regulation would require

25a change in the plant operation.

Individual Response: EPA agrees that review of site opera tions is important and expects that the reevaluations of the site pl ans will provide such review. For example, the AoR reevaluations offer a good opportunity to promote a dialogue be tween the owner or operator and the permitting authority. The final GS rule, at §§146.84(c), 146.90(j), and 146.94(d), requires owners or operators to review and update the AoR and corrective action pl an, the testing and monitoring plan, and the emergency and remedial response pl an throughout the life of the project. Owners or operators must review each plan and identify n ecessary amendments to the plan or demonstrate

to the Director that no amendment is needed. Th ese reviews must be performed within one year of an AoR reevaluation, following any significant changes to the facility (e.g., the addition of monitoring or injection wells), or when required by the Director . In no case can reviews occur less often than once every five years. Please see the final rule and the discussion of AoR reevaluations in the preamble for additional information.

Letter ID: 0213 Comment ID: 22951 Letter Lines: 433 to 441

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

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

Comment: - 73 FR 43519 -EPA requests comment on the proposed use of a te ntative 50-year fixed [post injection site care] timeframe that could be modified at the Director’s discretion based on monitoring and modeling data.

Response: AMWA supports a minimum 50-year time frame for post-injection site

care and recommends that the Director not be given any disc retion to shorten this time period. EPA notes in the pr oposal that "the pot ential risks of endangering USDWs will not decline within that timeframe given that stabilization may continue for several d ecades." AMWA also recommends that

Individual Response: EPA disagrees that the Director should not have discretion to shorten or lengthen the post-injection site care monitori ng period. EPA believes th at 50 years is an appropriate default post-injecti on site care timeframe. However, EPA recognizes that there may be sites where the 50 year post injection site ca re timeframe may be either not appropriate or more burdensome than necessary based on site-sp ecific conditions. For this reason, the GS rule offers owners or operators flexibility regard ing the duration of the PISC timeframe by: (1) allowing the Director discretion to shorten or lengthen the PI SC timeframe during the postinjection period based on site-specific data , pursuant to requirements at §146.93(b); or (2) affording the Director discretion to allow a Cl ass VI well owner or operator to demonstrate, during the permitting process based on substantial da ta, that an alternative PISC timeframe may be appropriate if it ensures non-endangermen t of USDWs pursuant to requirements at §146.93(c).

EPA believes however, that to ensure USDW protection from enda ngerment, a default timeframe for post-injection site care will be necessary in most cases. The default 50 year post-injection site care timeframe represents a reasonable and prot ective monitoring period based on a review of

26research studies, industry reports, and existing environmental programs, and evaluation of public

comments.

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: 0213 Comment ID: 22952 Letter Lines: 441 to 445

Comment Code: 1510 1.2.2.3 Need for additional study

Comment Code: 5200 2.8.2 Post injection site care (seeking comment) (40 CFR 146.93)

Comment: stabilization may continue for several d ecades." AMWA also recommends that

additional research be conducted to better understand the movement of CO2 plumes and that EPA provide guidance to owne r/operators about the criteria for monitoring and modeling data that would be necessary to demonstrate that the plume has stabilized and justify site closure.

Individual Response: EPA is developing guidance to assist owners or operators in evaluating well plugging, post-injection site care, and site closure requirements of §146.92 and §146.93. Additionally, the guidance will a ssist Directors in evaluating proposed well plugging plans and post-injection site car e and site closure plans under §146.92 and §146.93. The guidance describes recommended approaches for how an owner or operator could plug injection and monitoring wells; perform post-injection monitoring; de monstrate non-endangerment; and perform site closure activities. The guid ance will be available at http://water.epa.gov/type/groundwater /uic/wells_sequestration.cfm.

EPA agrees that continued research in all GS asso ciated fields will be integral to development of GS technology. EPA plans to, every six years, collect and review project data on early GS projects, including site char acterization, operational, mon itoring, and modeling data, to determine whether the appropriate amount a nd types of information and appropriate documentation are being collected, and to determ ine if modifications to the requirements are appropriate or necessary.

For additional information on these requirements, please also see the discussion of testing and monitoring under EPA’s Final Regu latory Approach in the pream ble to the final GS rule.

Letter ID: 0213 Comment ID: 22953 Letter Lines: 449 to 453 ; 459 to 464

Comment Code: 1510 1.2.2.3 Need for additional study

27Comment: In conclusion, AMWA again stresses the need for more research using the improved groundwater modeling technique s and variable density fl ow models for deeper aquifers now available. In addition, EPA must gather data now and in the future

to better understand the behavior of CO 2 plumes and the in teraction between water, CO2 and bedrock formations. Above all, drinking water needs should be

AMWA appreciates the opportunity to comment on EPA’s proposal. GHG reduction and mitigation measures including carbon sequestration are, understandably, very important issues to our members. As CCS technology has not been widely deployed in the U.S. to date, AMWA urges EPA and DO E to continue to perform the research suggested in these comments as well as follow-up assessments of the technology once deployed.

Individual Response: EPA agrees that continued research in all GS associated fields will be integral to development of GS technology. EPA published a Notice of Data Availability (NODA) and Request for Comment on August 31, 2009 (74 FR 44802), in which EPA described a study by the Lawrence Berkeley National Laboratory on the potential effects of CO2 injection, including far-field pressure e ffects, on ground water and surrounding formations to determine the potential for impacts on USDWs and human health in the event that a GS project is not properly sited, operated, or managed.

Letter ID: 0213 Comment ID: 22954 Letter Lines: 453 to 457

Comment Code: 1610 1.3.1 Risks to USDWs

Comment: water, CO2 and bedrock formations. Above all, drinking water needs should be considered paramount and EPA should consid er the future drinking water needs of the country in light of climate change. EPA’s final rule shoul d protect current and future USDWs from unintended conseque nces of CO2 geosequestration and moral

hazard.

Individual Response: As described above, The Agency ag rees that drinking water is an important resource to protect. The primary goa l of the UIC Program under the SDWA is to protect USDWs from endangerment. Consiste nt with SDWA §1422, the UIC program provides that no injection shall be authorized if it re sults in the movement of fluid containing any contaminant into USDWs, if the presence of th at contaminant may cause a violation of any primary drinking water regulation or may adversely affect the health of persons as specified in §144.12.

The GS rule, as part of the UIC program regulations, continues the Program’s mandate under the SDWA of ensuring the protection of USDWs from endangerment. EPA expects that the tailored permitting, siting, construction, operation, monitoring, and post-injection site care requirements in the GS rule will prevent leakage from injection formations and protect USDWs.

2829 Letter ID: 0213 Comment ID: 22955 Letter Lines: 466 to 473

Comment Code: 1210 1.1.1 Comments about the proposed rule

Comment: AMWA also recommends that EPA commit to update the rule regularly as more becomes known about CCS technology and the behavior of CO2 injected into the

subsurface. AMWA recommends that EPA work to update the rule every three to five years for the foreseeable future, as this technology will become more prevalent and injection methods and other sequestr ation techniques will likely improve. In developing this proposal, EPA has dem onstrated its ability to quickly bring staff up to speed on this technology and AMWA believes the Agency must continue chnological advances.

Individual Response: EPA agrees that an adaptive approach to the UIC GS rulemaking is appropriate. The Agency will use such an approa ch to ensure that USDWs are protected from endangerment and meet the potentially fast p ace of GS deployment. EPA believes that an adaptive approach will allow regulatory developmen t to proceed in time to meet the current and future demand for Class VI permits while recognizi ng the need to: continue to gather data from pilot projects and other research as it becomes available; and to enhanc e understanding of the

technical and administrative as pects of GS deployment, opera tion, and technology developments. EPA plans, every six years, to collect and review data on GS projects to determine whether the appropriate amount and types of information a nd appropriate documentation are being collected,

and to determine if modifications to the re quirements are appropr iate or necessary.