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.p

. 1

Janet Napolitano Stephen A

. Owens

Governor Director

December 23, 2008



# JAN 12 ZOOS

Water Docket

Environmental Protection Agency

Mailcode : 2822T

1200 Pennsylvania Ave

. NW

Washington, DC 20460

.

Re : Arizona Department of Environmental Quality Comments on Proposed EPA Carbon

Sequestration Rule, Docket ID No

. EPA-HQ-OW-2008-0390

Dear Sir or Madam

:

The Arizona Department of Environmental Quality (ADEQ has reviewed the referenced

proposed EPA rule

. ADEQ does not implement the Underground Injection Control (UIC)

program in Arizona, rather, ADEQ implements a state authorized Aquifer Protection Permit

(APP) program

. ADEQ has worked closely and effectively with the EPA Region IX UIC

program for many years to ensure consistency in approach to regulating discharges to Arizona's

aquifers

. ADEQ believes that the proposed rule contains appropriate provisions to regulate

geologic sequestration of carbon dioxide via the national UIC program

. In this comment, ADEQ

wishes to emphasize the unique statutory and geologic issues related to carbon injection and

sequestration in Arizona

.

While one of the EPA UIC program's criteria for exemption of aquifers is a concentration of

10,000 mg/L or more of total dissolved solids, Arizona has no similar exemption in current law

. Arizona law

classifies all aquifers for drinking water use (Arizona Revised Statutes § 49-224)

. In the past, the use of high-TDS groundwater for drinking in Arizona has not been necessary due

to sufficient supplies of high-quality water resources

. However, as the state's population has

grown and potable water resources have become scarce, many Arizona water providers must

now treat brackish groundwater to provide drinking water to their customers

. ADEQ believes

that the use of high-TDS groundwater in Arizona will only increase, and that saline aquifers

represent potentially valuable water resources

.



# JAN 0 4 2000

Northern Regional Office Southern Regional Office

1801 W

. Route 66 " Suite 117 " Flagstaff, AZ 86001 400 West Congress Street " Suite 433 " Tucson, AZ 85701

(928) 779-0313 (520) 628-6733 

## ARIZONA DEPARTMENT

OF



## ENVIRONMENTAL QUALITY

1110 West Washington Street " Phoenix, Arizona 85007

(602) 771-2300 " www .azdeq .gov

Printed on recycled paperp

. 2

EA UIC Comment

December 23, 2008

Page 2 of 2

The Region IX UIC program and the ADEQ APP program have historically cooperated on

various projects, including injection wells and dry wells

. The approach has been that EPA

Region 9 would not issue a UIC permit if ADEQ could not issue an APP

. ADEQ expects that

these cooperative efforts between the two programs will continue, particularly regarding

potential commercial scale geologic sequestration of carbon dioxide in deep saline aquifers in

Arizona

. The two permitting programs are now actively cooperating to permit a U .S

. Department of Energy funded pilot sequestration test in northeastern Arizona

. ADEQ looks

forward to continued cooperation with EPA's UIC program

.

Thank you for the opportunity to review and comment on the proposed rule

. If you have

questions, please contact ADEQ's Groundwater Section Manager, Michele Robertson, at (602)

771-4827

.

cc : Herb Guenther, Director, Arizona Department of Water ResourcesLetter ID: 0286

Commenter: Stephen Owens

Organization: Arizona Department of Environmental Quality

Letter ID: 0286 Comment ID: 25299 Letter Lines: 39 to 70

Comment Code: 4450 2.4.4.4 Use of aquifer exemptions (seeking comment)

Comment: The Arizona Department of Environmenta l Quality (ADEQ) has reviewed the

referenced proposed EPA rule . ADEQ does not implement the Underground Injection

Control (UIC) program in Arizona, rather , ADEQ implements a state authorized

Aquifer Protection Permit (APP) program. AD EQ has worked closely and effectively

with the EPA Region IX UIC program for ma ny years to ensure consistency in

approach to regulating discharges to Ar izona's aquifers. ADEQ believes that the

proposed rule contains appropriate provi sions to regulate ge ologic sequestration

of carbon dioxide via the national UIC program . In this comment, ADEQ wishes to

emphasize the unique statutory and geologi c issues related to carbon injection

and sequestration in Arizona.

While one of the EPA UIC program's criter ia for exemption of aquifers is a

concentration of 10,000 mg/L or more of total dissolved solids, Arizona has no

similar exemption in current law. Ariz ona law classifies all aquifers for

drinking water use (Arizona Revised Statutes § 49-224). In the past, the use of

high-TDS groundwater for drinking in Ariz ona has not been necessary due to

sufficient supplies of high-quality wate r resources. However, as the state's

population has grown and potable water re sources have become scarce, many

Arizona water providers must now treat brackish groundwater to provide drinking

water to their customers. ADEQ believes th at the use of high-TDS groundwater in

Arizona will only increase, and that sa line aquifers represent potentially

valuable water resources.

The Region IX UIC program and the ADEQ APP program have historically cooperated

on various projects, including injection we lls and dry wells. The approach has

been that EPA Region 9 would not issue a UIC permit if ADEQ could not issue an

APP. ADEQ expects that these cooperativ e efforts between the two programs will

continue, particularly regarding po tential commercial scale geologic

sequestration of carbon dioxide in deep saline aquifers in Arizona. The two

permitting programs are now actively cooperatin g to permit a U.S. Department of

Energy funded pilot sequestr ation test in northeastern Arizona. ADEQ looks

forward to continued cooperati on with EPA's UIC program.

Individual Response: EPA acknowledges the commenter's support of the proposed approach.

The UIC program's mission is th e protection of all USDWs

EPA believes that the creation of a new inject ion well class (VI) under th e existing UIC Program

12 is necessary to enable the use of GS as a clim ate change mitigation technology in a manner that

protects USDWs from endangerment. The GS rule contains minimum tec hnical criteria for the

permitting, geologic site characterization, AoR and corrective action, well construction,

operation, mechanical integrity testing, monitoring, financial responsibility, injection well

plugging, post-injection site care, and site closure of GS wells, which will ensure that USDWs

are protected from endangerment.

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.

The Agency clarifies that, in States with primary enforcement res ponsibility for underground

injection wells, the decision to allow aquifer ex emptions or the injection depth waivers at

§146.95 is at the discretion of the State pursuant to State statutes. If a State/UIC Director

believes that aquifer exemptions or injection dept h waivers are not appropriate for their State, the

Director has the authority to not include those provisions in th e State regulations.

For additional information on EPA's final approach to regulating GS, plea se see the final rule

and preamble.