	UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

	WASHINGTON, D.C.  20460

August 13, 2007

MEMORANDUM

SUBJECT:		Risk Assessment and Science Support Branch’s (RASSB’s)
Comments Concerning Chitosan Registration of Indoor Uses (128930)

FROM:		Norm Cook, Chief

Risk Assessment and Science Support Branch

Antimicrobials Division (7510P)

TO:			Adam Heyward, PM-34

Regulatory Management Branch II

Antimicrobials Division (7510P)

DP

BARCODE:	None

Pesticide

Chemical No.: 128930

Introduction

The Risk Assessment and Science Support Branch (RASSB) was requested by
staff from the Biopesticides and Pollution Prevention Division (BPPD) to
determine if an environmental assessment has been completed for chitosan
indoor uses registered by the Antimicrobials Division (AD) in prior
years.  RASSB checked branch and divisional files and was not able to
locate such an assessment.  However, based upon a review of the
available information we offer the following.

RASSB Conclusions/Comments

	It is our understanding that chitosan (poly-D-Glucosamine), under
Registration Number 81446-1, was registered by AD for various uses
including treatment of:  textiles, carpets, synthetic turf, laundry,
wallboard, etc.  The majority of chitosan uses appear to be indoor uses,
but obviously uses such as synthetic turf could be considered as an
outdoor use.  However, although RASSB did not perform an environmental
review for 81446-1, we note that chitosan is a naturally occurring
substance produced from chitin extracts of crustacean shells (e.g.,
crab, shrimp, and lobster).  Further, chitosan is used in numerous
applications involving ingestion through food and drugs, topical
application of drugs and cosmetics, intraperitoneal injections and nasal
inhalers.  Additionally, available information indicates that chitosan
is relatively nontoxic.

	Considering the above, RASSB concludes that environmental hazards and
exposures from use of the 81446-1 product should be minimal.  The
proposed use patterns, including synthetic turf (which is usually found
in enclosed stadiums), provide for minimal environmental exposure; and
the available information, which indicates relative nontoxicity, points
to minimal hazards for nontarget organisms.

	In closing, if there are any questions on the above, please contact
Norm Cook of RASSB.

cc:	N. Elkassabany, AD

	M. Hartman, AD

	D. Isbell, AD

	C. Pfeifer, BPPD

	R. Petrie, AD

 PAGE

 PAGE  2


[Federal Register Volume 77, Number 105 (Thursday, May 31, 2012)]
[Proposed Rules]
[Pages 32069-32071]
[FR Doc No: 2012-13194]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2012-0495; Directorate Identifier 2011-NM-236-AD]
RIN 2120-AA64

Airworthiness Directives; Gulfstream Aerospace LP (Type
Certificate Previously Held by Israel Aircraft Industries, Ltd.)
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: We propose to adopt a new airworthiness directive (AD) for
certain Gulfstream Aerospace LP (Type Certificate previously held by
Israel Aircraft Industries, Ltd.) Model Galaxy and Gulfstream 200
airplanes. This proposed AD was prompted by reports of degraded brake
performance during landing due to improperly-sized wear indicating
pins. This proposed AD would require determining the lengths of the
wear indicating pins of all brake assemblies, shortening the pin if the
wear indicating pin is too long, inspecting for normal brake wear, and
replacing brakes with new brakes if necessary. We are proposing this AD
to detect and correct improperly-sized wear indicating pins, which, if
not corrected, could result in worn-out brake pads and subsequent loss
of braking power, which could result in runway overruns.

DATES: We must receive comments on this proposed AD by July 16, 2012.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax:<PHONE_NUMBER>.
     Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE., Washington, DC between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact
Gulfstream Aerospace Corporation, P.O. Box 2206, Mail Station D-25,
Savannah, Georgia 31402-2206; telephone<PHONE_NUMBER>; fax<PHONE_NUMBER>;
email<EMAIL_ADDRESS>Internet http://www.gulfstream.com/product_support/technical_pubs/pubs/index.htm. You may review copies of the
referenced service information at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue SW., Renton, Washington. For information
on the availability of this material at the FAA, call<PHONE_NUMBER>.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations office
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Operations office (telephone<PHONE_NUMBER>) is
in the ADDRESSES section. Comments will be available in the AD docket
shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Tom Groves, Aerospace Engineer,
International Branch, ANM-116, Transport Airplane Directorate, FAA,

1601 Lind Avenue SW., Renton, Washington 98057-3356; telephone: (425)
227-1503; fax:<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2012-0495;
Directorate Identifier 2011-NM-236-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this proposed AD based on those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.

Discussion

    The Civil Aviation Authority of Israel (CAAI), which is the
aviation authority for Israel, has issued Israeli Airworthiness
Directive 32-11-10-13, dated October 31, 2011 (referred to after this
as ``the MCAI''), to correct an unsafe condition for the specified
products. The MCAI states:

    Two G200 operators experienced degraded brake performance during
landing. Subsequent investigation revealed that in both cases the
brake wear pins showed remaining life, but the brakes were worn to
the minimum pad thickness specified in the Brake Assembly Component
Maintenance Manual (CMM). It was found out that pins of incorrect
length were installed during brake assembly overhaul. When the brake
pads are fully worn without indication, loss of braking power is
expected, possibly causing runway overruns. This constitutes an
unsafe condition.

The required action is determining the lengths of the wear indicating
pins of all brake assemblies, shortening the pin if the wear indicating
pin is too long, inspecting for normal brake wear, and replacing brakes
with new brakes if necessary. You may obtain further information by
examining the MCAI in the AD docket.

Relevant Service Information

    Gulfstream Aerospace LP has issued Service Bulletin 200-32-389,
Revision 1, dated October 27, 2011. The actions described in this
service information are intended to correct the unsafe condition
identified in the MCAI.

FAA's Determination and Requirements of This Proposed AD

    This product has been approved by the aviation authority of another
country, and is approved for operation in the United States. Pursuant
to our bilateral agreement with the State of Design Authority, we have
been notified of the unsafe condition described in the MCAI and service
information referenced above. We are proposing this AD because we
evaluated all pertinent information and determined an unsafe condition
exists and is likely to exist or develop on other products of the same
type design.

Costs of Compliance

    Based on the service information, we estimate that this proposed AD
would affect about 155 products of U.S. registry. We also estimate that
it would take about 16 work-hours per product to comply with the basic
requirements of this proposed AD. The average labor rate is $85 per
work-hour. Required parts would cost about $0 per product. Where the
service information lists required parts costs that are covered under
warranty, we have assumed that there will be no charge for these parts.
As we do not control warranty coverage for affected parties, some
parties may incur costs higher than estimated here. Based on these
figures, we estimate the cost of the proposed AD on U.S. operators to
be $210,800, or $1,360 per product.
    We have received no definitive data that would enable us to provide
cost estimates for the on-condition actions specified in this proposed
AD.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. ``Subtitle VII: Aviation
Programs,'' describes in more detail the scope of the Agency's
authority.
    We are issuing this rulemaking under the authority described in
``Subtitle VII, Part A, Subpart III, Section 44701: General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.

Regulatory Findings

    We determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would not
have a substantial direct effect on the States, on the relationship
between the national Government and the States, or on the distribution
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify this proposed
regulation:
    1. Is not a ``significant regulatory action'' under Executive Order
12866;
    2. Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979);
    3. Will not affect intrastate aviation in Alaska; and
    4. Will not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.
    We prepared a regulatory evaluation of the estimated costs to
comply with this proposed AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by adding the following new AD:

Gulfstream Aerospace LP (Type Certificate previously held by Israel
Aircraft Industries, Ltd.): Docket No. FAA-2012-0495; Directorate
Identifier 2011-NM-236-AD.

(a) Comments Due Date

    We must receive comments by July 16, 2012.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Gulfstream Aerospace LP (Type Certificate
previously held by Israel Aircraft Industries, Ltd.) Model Galaxy
and Gulfstream 200 airplanes, certificated in any category, serial
numbers 004 through 250 inclusive.

(d) Subject

    Air Transport Association (ATA) of America Code 32: Landing
Gear.

(e) Reason

    This AD was prompted by reports of degraded brake performance
during landing due to improperly-sized wear indicating pins. We are
issuing this AD to detect and correct improperly-sized wear
indicating pins, which, if not corrected, could result in worn-out
brake pads and subsequent loss of braking power, which could result
in runway overruns.

(f) Compliance

    You are responsible for having the actions required by this AD
performed within the compliance times specified, unless the actions
have already been done.

(g) Determining and Correcting Pin Length and Inspecting Brake Wear

    Within 40 days after the effective date of this AD, determine
the length of the wear indicating pins of all the brake assemblies,
in accordance with the Accomplishment Instructions of Gulfstream
Service Bulletin 200-32-389, Revision 1, dated October 27, 2011.
    (1) If the length of the pins is within the limits specified in
Gulfstream Service Bulletin 200-32-389, Revision 1, dated October
27, 2011, before further flight, perform a normal brake wear
inspection in accordance with the Accomplishment Instructions of
Gulfstream Service Bulletin 200-32-389, Revision 1, dated October
27, 2011.
    (2) If any wear indicating pin is too long, as specified by the
limits in Gulfstream Service Bulletin 200-32-389, Revision 1, dated
October 27, 2011, before further flight, shorten the pin and perform
a normal brake wear inspection, in accordance with the
Accomplishment Instructions of Gulfstream Service Bulletin 200-32-
389, Revision 1, dated October 27, 2011.

(h) Brake Replacement

    If any brake fails the wear inspection required by paragraphs
(g)(1) and (g)(2) of this AD, before further flight, replace the
affected brakes with new brakes, in accordance with the
Accomplishment Instructions of Gulfstream Service Bulletin 200-32-
389, Revision 1, dated October 27, 2011.

(i) Credit for Actions Accomplished in Accordance With Previous Service
Information

    This paragraph provides credit for the actions required by
paragraph (g) of this AD, if those actions were performed before the
effective date of this AD using the Accomplishment Instructions of
Gulfstream Service Bulletin 200-32-389, dated October 20, 2011.

(j) Other FAA AD Provisions

    The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager,
International Branch, ANM-116, Transport Airplane Directorate, FAA,
has the authority to approve AMOCs for this AD, if requested using
the procedures found in 14 CFR 39.19. In accordance with 14 CFR
39.19, send your request to your principal inspector or local Flight
Standards District Office, as appropriate. If sending information
directly to the International Branch, send it to ATTN: Tom Groves,
Aerospace Engineer, International Branch, ANM-116, Transport
Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, Washington
98057-3356; telephone<PHONE_NUMBER>; fax<PHONE_NUMBER>.
Information may be emailed to<EMAIL_ADDRESS>
Before using any approved AMOC, notify your appropriate principal
inspector, or lacking a principal inspector, the manager of the
local flight standards district office/certificate holding district
office. The AMOC approval letter must specifically reference this
AD.
    (2) Airworthy Product: For any requirement in this AD to obtain
corrective actions from a manufacturer or other source, use these
actions if they are FAA-approved. Corrective actions are considered
FAA-approved if they are approved by the State of Design Authority
(or their delegated agent). You are required to assure the product
is airworthy before it is returned to service.

(k) Related Information

    (1) Refer to Israeli Airworthiness Directive 32-11-10-13, dated
October 31, 2011; and Gulfstream Service Bulletin 200-32-389,
Revision 1, dated October 27, 2011; for related information.
    (2) For service information identified in this AD, contact
Gulfstream Aerospace Corporation, P.O. Box 2206, Mail Station D-25,
Savannah, Georgia 31402-2206; telephone<PHONE_NUMBER>; fax 912-965-
3520; email<EMAIL_ADDRESS>Internet http://www.gulfstream.com/product_support/technical_pubs/pubs/index.htm. You may review
copies of the referenced service information at the FAA, Transport
Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington. For
information on the availability of this material at the FAA, call
425-227-1221.

    Issued in Renton, Washington, on May 18, 2012.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2012-13194 Filed 5-30-12; 8:45 am]
BILLING CODE 4910-13-P


[Federal Register: August 31, 2009 (Volume 74, Number 167)]
[Proposed Rules]
[Page 44802-44813]
[DOCID:fr31au09-45]

=======================================================================
-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 146

[EPA-HQ-OW-2008-0390; FRL-8951-3]
RIN 2040-AE98

Federal Requirements Under the Underground Injection Control
(UIC) Program for Carbon Dioxide (CO2) Geologic
Sequestration (GS) Wells; Notice of Data Availability and Request for
Comment

AGENCY: Environmental Protection Agency (EPA).

ACTION: Data availability; request for comment.

-----------------------------------------------------------------------

SUMMARY: Today's Notice supplements the proposed ``Federal Requirements
Under the Underground Injection Control (UIC) Program for Carbon
Dioxide (CO2) Geologic Sequestration (GS) Wells'' of July
25, 2008, presents new data and information, and requests public
comment on related issues that have evolved in response to comments on
the original proposal. This Notice contains preliminary field data from
the Department of Energy-sponsored Regional Carbon Sequestration
Partnership projects, the results of GS-related studies conducted by
the Lawrence Berkeley National Laboratory, and additional GS-related
research. Today's Notice also discusses comments and presents an
alternative the Agency is considering related to the proposed injection
depth requirements for Class VI wells.

DATES: Comments on the contents of this NODA must be received on or
before October 15, 2009. EPA does not plan to extend the comment period
for this Notice. EPA will hold a public hearing from 9 a.m. to 12 p.m.
and 1 p.m. to 4 p.m., CDT, September 17, 2009 in Chicago, IL.

ADDRESSES: The public hearing will be held at the Ralph H. Metcalfe
Federal Building, 77 W. Jackson Boulevard, Chicago, IL 60604. Due to
capacity limitations, we encourage you to indicate your intent to
participate through pre-registration. To pre-register, for directions,
and for site specific information, please visit the following Web site:
http://gshearing.cadmusweb.com/.
    Submit your comments, identified by Docket ID No. EPA-HQ-OW-2008-
0390, by one of the following methods:
     http://www.regulations.gov: Follow the on-line
instructions for submitting comments.
     Mail: Water Docket, Environmental Protection Agency,
Mailcode: 4101T, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
     Hand Delivery: Water Docket, EPA Docket Center (EPA/DC),
Public Reading Room, Room 3334, EPA West, 1301 Constitution Ave., NW.,
Washington, DC. Such deliveries are only accepted during the Docket's
normal hours of operation which are 8:30 a.m. to 4:30 p.m., and special
arrangements should be made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OW-2008-
0390. EPA's policy is that all comments received will be included in
the public docket without change and may be made available online at
http://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through http://
www.regulations.gov or e-mail. Contact EPA directly (see the FOR
FURTHER INFORMATION CONTACT section) prior to submitting CBI. The
http://www.regulations.gov Web site is an ``anonymous access'' system,
which means EPA will not know your identity or contact information
unless you provide it in the body of your comment. If you send an e-
mail comment directly to EPA without going through http://
www.regulations.gov your e-mail address will be automatically captured
and included as part of the comment that is placed in the public docket
and made available on the Internet. If you submit an electronic
comment, EPA recommends that you include your name and other contact
information in the body of your comment and with any disk or CD-ROM you
submit. If EPA cannot read your comment due to technical difficulties
and cannot contact you for clarification, EPA may not be able to
consider your comment. Electronic files should avoid the use of special
characters, any form of encryption, and be free of any defects or
viruses.
    Docket: All documents in the docket are listed in the http://
www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in http://www.regulations.gov or in hard copy at

the Water Docket, EPA Docket Center (EPA/DC), Public Reading Room, Room
3334, EPA West, 1301 Constitution Ave., NW., Washington, DC. The Public
Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room is<PHONE_NUMBER>, and the telephone number for the EPA
Docket Center is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: Mary Rose Bayer, Underground Injection
Control Program, Drinking Water Protection Division, Office of Ground
Water and Drinking Water (MC-4606M), Environmental Protection Agency,
1200 Pennsylvania Ave., NW., Washington, DC 20460; telephone number:
(202) 564-1981; e-mail address<EMAIL_ADDRESS>For general
information, contact the Safe Drinking Water Hotline, telephone number:
(800) 426-4791. The Safe Drinking Water Hotline is open Monday through
Friday, excluding legal holidays, from 10 a.m. to 4 p.m. Eastern time.
For general information about the public hearing, please contact Sean
Porse by phone<PHONE_NUMBER>, by e-mail at<EMAIL_ADDRESS>or by
mail at: US Environmental Protection Agency, Mail Code 4606M, 1200
Pennsylvania Ave., NW., Washington, DC 20460.

SUPPLEMENTARY INFORMATION:

I. General Information

    This Notice of Data Availability (NODA) presents new information
and data related to geologic sequestration (GS) of CO2
obtained after publication of the July 25, 2008, proposed rule,
``Federal Requirements Under the Underground Injection Control (UIC)
Program for Carbon Dioxide (CO2) Geologic Sequestration (GS)
Wells'' (73 FR 43492). The proposal is available online at http://
www.epa.gov/fedrgstr/EPA-WATER/2008/July/Day-25/w16626.htm.
Availability of this new information could change EPA's approach to the
final rulemaking.
    The purpose of this NODA is to request public comment on new data
and on related issues that have evolved in response to comments on the
original proposal. This Notice provides additional information and data
on the topic of injection depth as described in the July 25, 2008,
proposal (73 FR 43492) and presents an alternative that responds to
comments received on this issue. Therefore, EPA is providing the
opportunity for notice and comment on the information provided in this
Notice as a supplement to the proposed rule. The Agency seeks further
public comment on any and all aspects of the specific data and
alternatives it has identified in this Notice. EPA continues to review
the comments received on the proposed rule and will address those
comments and the comments submitted in response to this Notice in the
final action.
    Persons interested in recent research related to GS and proposed
injection depth requirements are encouraged to read and respond to this
NODA. Additionally, owners and operators, States, Tribes, and State co-
regulators involved in GS activities may wish to comment on this
publication.

Abbreviations and Acronyms

AL: Action Level
AoR: Area of Review
CBI: Confidential Business Information
CFR: Code of Federal Regulations
CCS: Carbon Capture and Storage
CO2: Carbon Dioxide
DOE: Department of Energy
EGR: Enhanced Gas Recovery
EPA: Environmental Protection Agency
EOR: Enhanced Oil Recovery
GS: Geologic Sequestration
GHG: Greenhouse Gas
IPCC: Intergovernmental Panel on Climate Change
km: kilometer
LBNL: Lawrence Berkeley National Lab
m: meter
mg/l: milligrams per liter
Mt: Megaton
MCL: Maximum Contaminant Level
NETL: National Energy Technology Laboratory
NWIS: National Water Information System
NODA: Notice of Data Availability
ORD: Office of Research and Development
PWS: Public Water System
PWSS: Public Water Supply Supervision
RCSPs: Regional Carbon Sequestration Partnerships
SDWA: Safe Drinking Water Act
SECARB: Southeast Regional Carbon Sequestration Partnership
STAR: Science to Achieve Results
SWP: Southwest Regional Partnership on Carbon Sequestration
TDS: Total Dissolved Solids
UIC: Underground Injection Control
US: United States
USDW: Underground Source of Drinking Water
USGS: United States Geological Survey

Definitions

    Action Level (AL): The concentration of lead or copper in water
specified in 40 CFR 141.80(c) which determines, in some cases, the
treatment requirements contained in subpart I of this part that a water
system is required to complete.
    Area of review (AoR): The region surrounding the geologic
sequestration project that may be impacted by the injection activity.
The area of review is based on computational modeling that accounts for
the physical and chemical properties of all phases of the injected
carbon dioxide stream.
    Buoyancy: Upward force on one phase (e.g., a fluid) produced by the
surrounding fluid (e.g., a liquid or a gas) in which it is fully or
partially immersed, caused by differences in pressure or density.
    Capillary force: Adhesive force that holds a fluid in a capillary
or a pore space. Capillary force is a function of the properties of the
fluid, and surface and dimensions of the space. If the attraction
between the fluid and surface is greater than the interaction of fluid
molecules, the fluid will be held in place.
    Carbon Capture and Storage (CCS): The process of capturing
CO2 from an emission source, (typically) converting it to a
supercritical state, transporting it to an injection site, and
injecting it into deep subsurface rock formations for long-term
storage.
    Carbon dioxide plume: The extent underground, in three dimensions,
of an injected carbon dioxide stream.
    Carbon dioxide (CO2) stream: Carbon dioxide that has been captured
from an emission source (e.g., a power plant), plus incidental
associated substances derived from the source materials and the capture
process, and any substances added to the stream to enable or improve
the injection process. This subpart does not apply to any carbon
dioxide stream that meets the definition of a hazardous waste under 40
CFR part 261.
    Class VI wells: Wells used for geologic sequestration of carbon
dioxide beneath the lowermost formation containing a USDW.
    Confining zone: A geologic formation, group of formations, or part
of a formation stratigraphically overlying the injection zone that acts
as a barrier to fluid movement.
    Corrective action: The use of Director approved methods to assure
that wells within the area of review do not serve as conduits for the
movement of fluids into underground sources of drinking water (USDWs).
    Director: The person responsible for permitting, implementation,
and compliance of the UIC program. For UIC programs administered by
EPA, the Director is the EPA Regional Administrator; for UIC programs
in Primacy States, the Director is the person responsible for
permitting, implementation, and compliance of the State, Territorial,
or Tribal UIC program.
    Enhanced Oil or Gas Recovery (EOR/EGR): Typically, the process of
injecting a fluid (e.g., water, brine, or CO2) into an oil
or gas bearing formation to

recover residual oil or natural gas. The injected fluid thins
(decreases the viscosity) or displaces small amounts of extractable oil
and gas, which is then available for recovery. This is also known as
secondary or tertiary recovery.
    Formation or geological formation: A layer of rock that is made up
of a certain type of rock or a combination of types.
    Geologic sequestration (GS): The long-term containment of a
gaseous, liquid or supercritical carbon dioxide stream in subsurface
geologic formations. This term does not apply to its capture or
transport.
    Geologic sequestration project: An injection well or wells used to
emplace a CO2 stream beneath the lowermost formation
containing a USDW. It includes the subsurface three-dimensional extent
of the carbon dioxide plume, associated pressure front, and displaced
brine, as well as the surface area above that delineated region.
    Injectate: The fluids injected. For the purposes of this rule, this
is also known as the CO2 stream.
    Injection zone: A geologic formation, group of formations, or part
of a formation that is of sufficient areal extent, thickness, porosity,
and permeability to receive carbon dioxide through a well or wells
associated with a geologic sequestration project.
    Maximum Contaminant Level (MCL): The maximum permissible level of a
contaminant in water which is delivered to any user of a public water
system.
    Model: A representation or simulation of a phenomenon or process
that is difficult to observe directly or that occurs over long time
frames. Models that support GS can predict the flow of CO2
within the subsurface, accounting for the properties and fluid content
of the subsurface formations and the effects of injection parameters.
    Pore space: Open spaces in rock or soil. These are filled with
water or other fluids such as brine (i.e., salty fluid). CO2
injected into the subsurface can displace pre-existing fluids to occupy
some of the pore spaces of the rocks in the injection zone.
    Public Water System (PWS): A system for the provision to the public
of water for human consumption through pipes or, after August 5, 1998,
other constructed conveyances, if such system has at least fifteen
service connections or regularly serves an average of at least twenty-
five individuals daily at least 60 days out of the year. Such term
includes: any collection, treatment, storage, and distribution
facilities under control of the operator of such system and used
primarily in connection with such system; and any collection or
pretreatment storage facilities not under such control which are used
primarily in connection with such system. Such term does not include
any ``special irrigation district.'' A public water system is either a
``community water system'' or a ``noncommunity water system.''
    Pressure front: The zone of elevated pressure that is created by
the injection of carbon dioxide into the subsurface. For GS projects,
the pressure front of a CO2 plume refers to the zone where
there is a pressure differential sufficient to cause the movement of
injected fluids or formation fluids into a USDW.
    Saline formations: Deep and geographically extensive sedimentary
rock layers saturated with waters or brines that have a high total
dissolved solids (TDS) content (i.e., over 10,000 mg/l TDS). Saline
formations offer great potential for CO2 storage capacity.
    Stratigraphic zone (unit): A layer of rock (or stratum) that is
recognized as a unit based on lithology, fossil content, age or other
properties.
    Total Dissolved Solids (TDS): The measurement, usually in mg/l, for
the amount of all inorganic and organic substances suspended in liquid
as molecules, ions, or granules. For injection operations, TDS
typically refers to the saline (i.e., salt) content of water-saturated
underground formations.
    Transmissive fault or fracture: A fault or fracture that has
sufficient permeability and vertical extent to allow fluids to move
between formations.
    Trapping: The physical and geochemical processes by which injected
CO2 is sequestered in the subsurface. Physical trapping
occurs when buoyant CO2 rises in the formation until it
reaches a layer that inhibits further upward migration or is
immobilized in pore spaces due to capillary forces. Geochemical
trapping occurs when chemical reactions between dissolved
CO2 and minerals in the formation lead to the precipitation
of solid carbonate minerals.
    Underground Source of Drinking Water (USDW): as defined under 40
CFR part 144.3, an aquifer or portion of an aquifer that supplies any
public water system or that contains a sufficient quantity of ground
water to supply a public water system, and currently supplies drinking
water for human consumption, or that contains fewer than 10,000 mg/l
total dissolved solids and is not an exempted aquifer.
    Special Accommodations: For information on access or accommodations
for individuals with disabilities, please contact Sean Porse at (202)
564-5990 or by e-mail at<EMAIL_ADDRESS>Please allow at least 10
days prior to the meeting, to give EPA time to process your request.

II. What Did EPA Propose?

    On July 25, 2008, EPA published the proposed ``Federal Requirements
Under the Underground Injection Control (UIC) Program for Carbon
Dioxide (CO2) Geologic Sequestration (GS) Wells.'' (73 FR
43492) The Agency proposed a new class of injection well (Class VI)
along with technical criteria for permitting GS wells, including
criteria for geologic site characterization, area of review (AoR) and
corrective action, well construction, operation, mechanical integrity
testing, monitoring, well plugging, post-injection site care, and site
closure. These standards, if finalized, would protect underground
sources of drinking water (USDWs) under the Safe Drinking Water Act
(SDWA). The technical criteria in the proposed rule are based on the
existing UIC regulatory framework under the SDWA for deep injection
wells, with modifications to address the unique nature of
CO2 injection for GS.
    Existing GS project experience, natural and industrial analogs,
research, and current regulatory experience with underground injection
were considered in the development of the proposed rule. Ongoing
research builds upon the existing foundation of substantial literature
on CO2 injection and storage, some of which is available in
the docket for this rulemaking. While CO2 injection to
extract oil and gas has taken place for many years, the use of UIC
wells to inject large quantities of CO2 for long-term
storage is a relatively new practice. There are current projects and
research underway that examine and demonstrate the effectiveness of
underground injection as a tool for sequestering CO2.
    For example, there are four commercial projects in operation today:
     Sleipner (Norwegian North Sea)--1 Mt CO2/yr
injected since 1996;
     Weyburn (Canada)--1 Mt CO2/yr injected since
2000;
     In Salah (Algeria)--1.2 Mt CO2/yr injected
since 2004;
     Snohvit (Norway)--0.7 Mt CO2/yr injected since
2008.
    Many additional large-scale projects are funded and under
development worldwide.
    The purpose of this NODA is to provide an update on newly available
information and data related to research focused specifically on GS for
long-term storage--with particular emphasis on data, research, and
information that has become available since the July proposal
publication.

    In addition, the proposed rule contains a discussion of injection
depth. In the July 2008 FR Notice, EPA proposed that the injection of
CO2 be confined to areas below the lowermost USDW (in the
absence of an aquifer exemption). This approach is consistent with the
approach used for other deep UIC wells; however, circumstances in a few
States may warrant an alternative approach. Today's Notice provides
additional discussion on an alternative the Agency is considering
related to injection depth for GS wells.
    EPA received a number of comments indicating that the Agency should
further explore environmental and regulatory issues beyond the scope of
the proposed SDWA requirements for underground injection of
CO2 for GS. EPA recognizes that a more comprehensive
framework may be needed and that some stakeholders remain uncertain
with respect to the potential applicability of other Federal
environmental statutes such as the Clean Air Act, the Resource
Conservation and Recovery Act, and the Comprehensive Environmental
Response, Compensation, and Liability Act to various aspects of
geologic sequestration of CO2. The Agency is currently
evaluating the need for a more comprehensive regulatory framework to
provide legal guidance regarding this emerging technology. If the
Agency chooses to pursue a more comprehensive regulatory approach to
this subject, it will seek public comment on any proposal it develops
for this framework and will also endeavor to issue a more comprehensive
rule in the same time frame as it has planned for the stand-alone UIC
GS rulemaking.

III. Research, Data Analysis, and Findings

A. Content of NODA and Summary of Comments

    In this Notice, EPA is providing a short summary of several ongoing
GS studies and interim information on current GS projects relevant to
topics within the proposed GS regulation. This information and data
were provided or made available after publication of the proposal in
July 2008. More detailed information on the GS research and projects
discussed below is available for review online as part of the docket
for this rulemaking. EPA is providing this data and associated project
summaries because the Agency expects that there may be additional
studies and data on other GS projects, the use of existing
technologies, and GS-related research that may inform the Agency's
regulatory development process for GS. Such data could contribute to
the Agency's understanding of site characterization, well construction,
operation, and monitoring requirements. The Agency requests comment on
data and research discussed in today's Notice and how the Agency might
use this data and research in developing the final rule. The Agency
also requests submission of additional GS studies related to the data
and research discussed in this Notice to inform the GS rulemaking.
    In the preamble of the proposed rule, EPA described an adaptive
approach to developing regulations for GS. This approach would allow
the Agency to establish regulations to protect USDWs and enable the
Agency to make changes to regulations over time as information from
demonstration projects and other studies becomes available. EPA
received comments from stakeholders requesting that additional data be
made available to the public before a final rulemaking (particularly
related to specific areas of GS) and indicating that more research is
needed to support GS in general. Many commenters suggested that
supplementary research on GS is necessary prior to rule promulgation
and that EPA should wait until the Department of Energy (DOE)-sponsored
Phase II and Phase III pilot projects are complete before finalizing
the GS rule. Others believed that a final rulemaking should proceed and
that new information and data from ongoing GS research should be
considered and incorporated over time as part of an adaptive rulemaking
process. Comments on the proposal encouraged additional research and
investigations on areas including (but not limited to): Confining zone
characterization; modeling; CO2 plume movement;
geochemistry; impacts of GS on saline formations; leakage from
abandoned wells caused by material and cement degradation; potential
pathways for contamination of USDWs; leak mitigation and remediation;
and criteria for determining that the CO2 plume has
stabilized.
    The Agency is actively tracking the progress of the Regional Carbon
Sequestration Partnership (RCSP) GS and carbon capture and storage
projects. The RCSPs have been compiling information related to their
pilot and demonstration projects and have been developing research
projects related to these efforts. A summary of several of these
projects is available in today's Notice.
    In addition, EPA's Office of Research and Development is conducting
intramural and extramural research activities to develop modeling and
monitoring tools for protecting underground sources of drinking water.
Laboratory, modeling, and field investigations are focusing on a
variety of injection and storage scenarios and candidate injection
sites. Analytic and semi-analytic models are being developed and
evaluated for determining the area of review based on geologic and
hydrologic conditions. Comprehensive laboratory tests are being applied
to the development and field-testing of monitoring strategies that can
detect migration of fluids into shallow aquifers and assess potential
geochemical impacts. The ultimate goal of these research activities is
to provide more robust tools for permitting, monitoring, and evaluating
GS sites from injection through post-injection site care and site
closure to prevent endangerment of USDWs. EPA is also funding six
projects for the study of ground water and human health impacts of GS
through the Science To Achieve Results (STAR) grant program. The awards
will be announced this fall on EPA's Web site (http://es.epa.gov/ncer/
).
    Furthermore, EPA and DOE have jointly supported GS-related studies
at Lawrence Berkeley National Lab (LBNL), described in Section II.B.
These studies use modeling to predict the potential impacts on ground
water from GS activities.

B. DOE-Sponsored Regional Carbon Sequestration Partnership Projects

    Currently, DOE's National Energy Technology Laboratory (NETL) is
developing and/or operating approximately 30 GS projects, a number of
which have either completed injection or are in the process of
injecting CO2. The purpose of these projects is to ``help
determine the best approaches for capturing and permanently storing
gases that can contribute to global climate change'' and to determine
``the most suitable technologies, regulations, and infrastructure needs
for carbon capture, storage, and sequestration in different parts of
the country'' (http://www.netl.doe.gov/technologies/carbon_seq/
partnerships/partnerships.html). Through cooperation with DOE, EPA has
obtained pilot project data from several of these GS projects. RCSPs
are conducting pilot and demonstration projects to study: site
characterization (including injection and confining formation
information, core data and site selection information); well
construction (well depth, construction materials, and proximity to
USDWs); frequency and types of tests and monitoring conducted (on the
well and on the project site); modeling and

monitoring results; and injection operation (injection rates,
pressures, and volumes, CO2 source and co-injectates). In
addition to information available in the docket for this NODA,
information on some of these projects is available at http://
www.netl.doe.gov/publications/proceedings/08/rcsp/. The following is a
short summary of select project activities and data generated.
Escatawpa, Mississippi (MS); Southeast Regional Carbon Sequestration
Partnership (SECARB)
    SECARB is conducting a CO2 injection test in Jackson
County, MS into a deep saline reservoir along the Gulf Coast that had
not previously been characterized for oil and gas exploration. The
injection zone, 9,500 feet (2,896 meters) deep in the Lower Tuscaloosa
Massive Sand Unit, is overlain by two confining layers. The site is
near the Victor J. Daniel Power Plant, the source of the
CO2, which was delivered to the injection site via truck.
    Characterization of the site is based on a wealth of geophysical
and core-derived information, including well core samples, open-hole
and cased-hole well logging, baseline vertical seismic profiling, and
pressure transient testing. Baseline sampling and analysis of formation
fluids and soil flux sampling were also performed. The SECARB team
performed a 3-dimensional simulation to estimate injectivity, storage
capacity, and long-term fate of the injected CO2. The model
estimated that the plume would extend up to 350 feet (106.7 meters) at
the end of the injection test.
    An injection well and a monitoring well were drilled at the site.
The injection well is permitted by the Mississippi Department of
Environmental Quality as a UIC Class V experimental well. Both the
injection and monitoring well were constructed with surface and long-
string casing that was cemented from the injection zone to the surface.
Pre-injection mechanical integrity tests of the injection and
monitoring well (annulus pressure test, radioactive tracer survey,
differential temperature survey, and pressure fall-off tests) met UIC
Class I requirements.
    In October of 2008, 3,027 tons (2,746 tonnes) of CO2
were injected into the well; injection rates averaged 170 to 180 tons/
day (154 to 163 tonnes/day). Continuous monitoring devices were used to
record (at 30 second intervals): Injection pressure, annular pressure,
temperature, and rate. The injection was complete on October 28, 2008.
    SECARB is continuing to monitor activities at the site through
surface or near-surface monitoring for upward CO2 seepage
via groundwater sampling, soil flux sampling and tracer detection. The
purpose of this monitoring and sampling is to determine whether
CO2 is migrating upward from the injection zone. To date,
there has been no indication of the return of the injected
CO2 in the shallow subsurface. SECARB also plans to employ
time-lapse seismic and geophysical tools to determine the deep
subsurface fate of the injectate.
    This SECARB project employs, demonstrates, and validates the EPA's
proposed Class VI well construction, operational, and monitoring
requirements. The use of surface and near-surface monitoring techniques
provides the EPA with preliminary information regarding the efficacy
and appropriateness of these technologies at certain sites; and
supports the need for a site-specific monitoring plan that will allow
use of a range of monitoring technologies suitable for each unique GS
site. This information and public comments on this research will be
used to inform the Agency's final rulemaking.
    For additional information about the Escatawpa Project, see the
full report in the docket for today's publication.
Aneth Field, Paradox Basin, Southeast Utah (UT); Southwest Regional
Partnership on Carbon Sequestration (SWP)
    The Aneth Field is the site of an experimental combined EOR-GS test
by the Southwest Partnership. The primary CO2 injection
target is the carbonate Paradox Formation, which is approximately 5,600
to 5,800 feet (1,707 to 1,768 meters) deep, and is overlain by the low-
permeability Gothic Shale. Petrographic, geochemical and mechanical
analyses of the Gothic Shale are underway or planned.
    CO2 injection began in August 2007, and approximately
150,000 tons (136,077 tonnes) of CO2 have been injected to
date. Extensive monitoring of the site is complete or underway.
Monitoring activities at the site include time-lapse vertical seismic
profiling, microseismic monitoring, geochemical and tracer tests,
CO2 soil flux measurements, a surface fracture and banding
study, and self-potential monitoring.
    Monitoring data are being used to establish parameters for state-
of-the-art mathematical reservoir models, which include coupling of
multiphase CO2-ground water flow, rock deformation, and
chemical reactions to evaluate residence times, migration patterns and
rates, and effects of CO2 injection on fluid pressures and
rock strain.
    The Aneth Field project confirms the need for a project design with
a robust monitoring plan, and tests the importance of monitoring and
modeling agreement in GS projects. In addition, the project
demonstrates the utility of various monitoring technologies that may be
used by owners and operators of Class VI wells. This information and
public comments on this research will be used to inform the Agency's
final rulemaking.
Pump Canyon Site, Near Archuleta, New Mexico (NM); Southwest Regional
Partnership on Carbon Sequestration (SWP)
    The SWP is conducting a Phase II project of CO2
injection into deep, unmineable coal seams at the Pump Canyon Site near
Archuleta, NM. To support characterization of the site, the SWP is
performing a ``seal analysis'' of the ability of the Kirtland Formation
to act as a barrier to the movement of CO2 or other
reservoir fluids. The Kirtland Formation is a major, regional aquitard
and reservoir seal that directly overlies the geologic formation
containing the coal seams.
    To characterize the Kirtland Formation, detailed studies of
geological core samples, downhole geophysical logs, and outcrop studies
were conducted. Complete and in-progress laboratory analyses include
electron microscopic studies of petrographic and petrophysical
properties; capillary pressure measurements; multiscale fracture
characterization using well logs and core analysis; descriptions of
stratigraphic columns and sedimentary structures based on cores; pore
size distributions analysis using BET (Brunauer-Emmett-Teller), and
geomechanical analyses of the caprock and overlying aquifer.
    Operators are actively monitoring potential surface deformation
from injection through the use of tilt meters and radar-based
Interferrometric Synthetic Aperture Radar (InSAR) in addition to
monitoring the site's injection pressure. They are also tracking the
CO2 plume through continuous sampling of immediate offset
production wells and through perfluorocarbon gas tracers (PFT) and
naphthalene sulfonate water tracers (NST) introduced into the
CO2 injection stream. These tracers are used for
identification in the unlikely event of reservoir leakage.
    The Agency sought comment on using unmineable coal seams for GS in
the proposed rule. The investigation at Pump Canyon will inform a
determination on whether CO2 can be effectively and safely
sequestered in coal seams.

    For further information on aspects of the Pump Canyon project,
please refer to data available in the NODA docket.

C. Lawrence Berkeley National Laboratory (LBNL) Studies

    An improperly managed GS project has the potential to endanger
USDWs. The factors that increase the risk of USDW contamination are
complex and can include improper siting, construction, operation and
monitoring of GS projects. The proposed GS requirements address
endangerment to USDWs by establishing new Federal requirements for the
proper management of CO2 injection and storage. Risks to
USDWs from improperly managed GS projects can include CO2
migration into USDWs, causing the leaching and mobilization of
contaminants (e.g., arsenic, lead, and organic compounds), changes in
regional groundwater flow, and the movement of greater salinity
formation fluids into USDWs, causing degradation of water quality. As
mentioned in Section II of this Notice and in the proposal,
CO2 has been injected on large scales at four sites: at
Sleipner in the North Sea, at In Salah in Algeria, at Snohvit in
Norway, and in the Weyburn Field in Alberta, Canada. There have been no
documented cases of leakage from these projects. Additionally, for
decades, the oil and gas industry has been safely injecting
CO2 for the purpose of enhanced oil and gas recovery.
    LBNL is studying the potential effects of CO2 injection
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. Specifically, LBNL is
evaluating the potential for GS to cause changes in ground water
quality as a result of CO2 leakage and subsequent
mobilization of trace elements such as arsenic, barium, cadmium,
mercury, lead, antimony, selenium, zinc, and uranium. In addition, LBNL
is evaluating basin-scale hydrological impacts of large-volume
injection of CO2 on groundwater aquifers and in particular,
the pressure front impacts caused by GS. Summaries of the interim
results for these research areas are discussed below. The full
publications are available in the docket and on LBNL's Web site at
http://esd.lbl.gov/GCS/projects/CO2/index_CO2.html.
1. Ground Water Quality Changes Related to the Mobilization of Trace
Elements
Summary
    LBNL used a comprehensive computational model to evaluate the
potential impact of CO2 leaking from deep geologic
sequestration sites on the concentrations of trace elements in potable
ground waters (Birkholzer et al., 2008a). LBNL estimated the amount of
trace elements from native mineral species that could potentially be
mobilized by the intrusion of CO2, and the potential ground
water concentrations that could result. LBNL then compared these
estimates to EPA's Maximum Contaminant Levels (MCLs) and Action Levels
(ALs) for drinking water to determine the potential for drinking water
standards to be exceeded. It is important to note that model results
were dependent on several assumptions and parameter values with a large
degree of uncertainty, such as dissolution and dissociation constants.
LBNL recommended that further studies should be conducted, including
laboratory or field experiments and evaluation of natural analogues.
    LBNL conducted multiple model runs to assess a variety of scenarios
and aquifer conditions and, as discussed below, found that if injected
CO2 comes into contact with shallow USDWs, some trace
element concentrations such as arsenic could increase.
Identification of Trace Elements of Concern
    An important step in developing the model used to assess the
different scenarios was the identification of naturally occurring
minerals that could act as a source of trace elements in ground water
if they were to come into contact with CO2. This
identification was accomplished through an extensive review of the
scientific literature, through which potential minerals of concern were
identified. The presence of these minerals in aquifer rocks was
indirectly substantiated through an evaluation of more than 38,000
water-quality analyses from potable aquifers reported in the United
States Geological Survey's (USGS) National Water Information System
(NWIS). While the abundances of these host minerals are typically very
small, all trace elements targeted for study occur frequently in soils,
sediments, and aquifer rocks.
    A preliminary assessment of CO2-related water quality
changes, including pH, was conducted by calculating the expected
equilibrium concentrations of trace elements as a function of the
amount of CO2 in a representative potable groundwater.
Results of this modeling obtained for typical aquifers under reducing
conditions indicate that arsenic could potentially exceed Federal
drinking water standards at elevated CO2 concentrations (40
CFR 141.62 (b)(16)). Other trace elements, such as barium, cadmium,
lead, antimony, and zinc, may also be mobilized in certain
circumstances, but the majority of results did not show mobilization at
levels exceeding the MCL or AL.
    LBNL used reactive-transport modeling to further study the fate and
transport of arsenic and lead in a representative potable aquifer as
influenced by leakage of CO2. This study is described as
follows:
Prediction of the Fate and Transport of Trace Elements
    LBNL used the reactive-transport model TOUGHREACT to 1) study and
predict the transport of CO2 within a shallow aquifer, 2)
estimate potential geochemical changes caused by the presence of
CO2, and 3) estimate the fate and transport of mobilized
trace elements. LBNL conducted sensitivity studies to account for a
range of conditions found in potable aquifers throughout the US and to
evaluate the uncertainty associated with geochemical processes and
model parameters. Starting with a representative ground water under
equilibrium conditions, the model was used to estimate the impact of
CO2 leakage into the aquifer for 100 years. For this
analysis, the investigators assumed a hypothetical release scenario
based on CO2 escape from a deep geologic sequestration site
via a preferential pathway, such as a fault zone, entering the shallow
aquifer at a constant rate.
    Results from this model simulation suggest that if CO2
were to leak into a shallow aquifer, the potential for mobilization of
lead and arsenic could be enhanced, causing increases in the
concentration of these trace elements in ground water. While LBNL
studies did suggest that CO2 interaction could cause
significant concentration increases compared to the initial water
composition, the MCL for arsenic was exceeded in only a few simulation
scenarios, while the lead concentrations remained below the AL under
all scenarios. It is important to emphasize that these studies looked
at potential consequences of CO2 leakage into the USDW, not
the likelihood of such leakage occurring. The goal of the UIC program
and these regulations is to ensure that injectate does not contaminate
USDWs in the first place.

    The Agency will use these preliminary results and public comments
on this research as well as potential site-specific analyses, to refine
and inform site characterization, monitoring, and remediation
requirements and guidance, if necessary, in the Agency's final
rulemaking. The Agency seeks comment on this research and any
additional studies related to a) mobilization of constituents and b)
the likelihood or frequency of such leakage/risks.
2. Basin-Scale Hydrologic Impacts of CO2 Storage
Summary
    Pressure build-up from large volume CO2 sequestration
has been researched since the early 1990s. Recent studies have focused
on better understanding large-scale pressure responses for future
geologic sequestration projects (Zhou et al., 2008; Van der Meer and
Yavuz, 2008; Nicot, 2008; Birkholzer et al., 2009). LBNL studied a
hypothetical, future scenario of GS in a sedimentary basin as an
illustrative example to demonstrate the potential for basin-scale
hydrologic impacts of CO2 storage (Birkholzer et al.,
2008b).
Sedimentary Basin Case Study
    The example basin considered in this case study contains deep
saline formations that are potential targets for large-scale
CO2 storage projects because they are geologically favorable
for permanent CO2 storage and the region has many large
stationary sources of CO2. The basin contains a thick,
extensive, high porosity, high permeability sandstone that is the
primary target for CO2 storage. A superior confining shale
layer is also present, making it an ideal site for geologic
sequestration projects.
    LBNL used a preliminary computational hydrogeologic model of the
basin to simulate regional ground water flow patterns as influenced by
large-scale deployment of GS in the region. The model assumed a
scenario where 20 independent GS projects spaced throughout the center
of a 570 kilometers (km) by 550 km (354 miles by 342 miles) model
domain each injected 5 million tonnes (5.51 million tons) of
CO2 per year over 50 years. (The largest injection today is
on the order of a million/tons/per year). Modeling results for this
simulation indicated that the maximum size of each CO2 plume
was 6-8 km (3.7-5 miles) with lateral separation between each GS
project of about 30 km (18.6 miles). These model results suggest that
the basin is favorable for effective trapping of CO2.
    In addition, simulation runs indicated that injection pressures did
not exceed fracture pressure or the maximum value used in the model for
this basin. However, results also indicated that far-field pressure
changes could propagate as far away as 200 km (124 miles) from the core
injection area where the geologic sequestration projects are located.
After CO2 injection ended in the simulation, pressure
buildup in the injection zone began to dissipate while the far-field
pressure response continued to increase and expand. For this simulation
example, a pressure increase of 0.5 bar existed at an areal extent of
nearly 400 km by 400 km (249 miles by 249 miles) after 50 years. These
model results indicate that basin-wide pressure influences can be large
and may have intersecting pressure perturbations in a multiple-site
scenario. While simulated changes in salinity within the storage
formation were relatively small, the predicted pressure changes could
push saline water upward into overlying aquifers if localized pathways
such as conductive faults existed. As these large scale simulations
indicated, limitations on injection volumes related to basin-scale
pressure build-up should be considered during CO2 capacity
estimation.
    EPA believes that the example studied by LBNL illustrates the
importance of basin-scale evaluation of reservoir pressures and far-
field pressures resulting from CO2 injection. EPA requests
comment on this study and welcomes additional studies that provide
information on the need for basin-scale evaluations for GS injection.

D. Additional GS Research

    There are international, consensus-based and peer-reviewed reports
on CCS, including the Intergovernmental Panel on Climate Change (IPCC)
Special Report on Carbon Dioxide Capture and Storage (IPCC, 2005),
which specifically includes a chapter on GS drawn from published
literature and research studies. Comprehensive reviews of the results
from GS research are also available (e.g., Holloway, 2001; Friedman,
2007; Tsang et al., 2008). EPA will continue to track research project
development and literature published by DOE and international
governments and organizations including the International Energy Agency
(IEA), IEA Greenhouse Gas Programme, and other major international CCS
initiatives.
    With respect to geologic and reservoir modeling, EPA has conducted
one such synthesis and analysis of GS research to inform the rulemaking
efforts. Schnaar and Digiulio (2009) present a research review of over
forty GS modeling studies spanning from 1993-2008. This review found
that GS models are based on pre-existing codes that have been developed
for predicting the movement of water and solutes in soil, the behavior
of groundwater contaminants at hazardous waste sites, and the recovery
of oil and gas from petroleum-bearing formations. However, modeling the
injection and sequestration of CO2 poses unique challenges,
such as the need to properly characterize CO2 transport
properties across a large range of temperatures and pressures, and the
need to couple multiphase flow, reactive transport, and geomechanical
processes. The authors reviewed studies that demonstrated the use of
modeling in project design, site characterization, assessments of
leakage, and site monitoring.
    The complete modeling review is available in the online public
docket at http://www.regulations.gov. A list of recent publications
addressing potential environmental risks and risk management approaches
for GS sites is also available in the docket. The Agency may use
information generated from these studies to identify implementation
guidance needs and refine the proposed requirements. EPA seeks comment
on these studies and requests other research on geologic and reservoir
modeling as well as research associated with potential environmental
risks and risk management approaches for GS.

IV. Injection Depth for GS Projects

A. What did EPA propose for Class VI well injection depth relative to
the location of USDWs?

    In the proposed rule, EPA defined Class VI injection wells as wells
used for GS (injection) of CO2 beneath the lowermost
formation containing a USDW. In Section III.A.4 of the preamble, EPA
discussed Injection Depth in Relation to USDWs to further clarify the
Agency's expectations regarding injection depth for Class VI wells. The
proposed requirements would preclude injection of CO2 into
zones in between and above USDWs. EPA is aware that confining Class VI
CO2 injection to below the lowermost USDW may restrict the
use of sequestration in areas of the country with deep USDWs where well
construction would be technically impractical or infeasible. As
proposed, the definition would also preclude injection of
CO2 into shallow formations such as coal seams and basalts.
The Agency requested comment on alternative approaches that would allow
injection between and/or above the

lowermost USDW and thus potentially allow for more areas to be
available for GS while continuing to prevent endangerment of USDWs.
    Approaches on which the Agency sought comment in the preamble, as
alternatives to the proposed injection depth requirements included:
     Allowing Class VI CO2 injection above the
lowermost USDW when the Director determines that geologic conditions
exist that will prevent fluid movement into adjacent USDWs;
     Allowing the use of an aquifer exemption process for Class
VI injection; and,
     Establishing, by regulation, a minimum injection depth for
GS of CO2.

B. Why did EPA propose that Class VI wells inject below the lowermost
USDW?

    EPA initiated the regulatory development process for GS and
proposed new, tailored Federal requirements appropriate for the unique
nature of injecting large volumes of CO2 for long-term
storage to ensure that USDWs are not endangered. The proposed injection
depth requirements for Class VI wells are consistent with the siting
and operational requirements for deep, technically sophisticated Class
I wells and are an important component of the UIC program.
    The basis of these requirements is the principle that placing
distance between the injection formation and USDWs decreases risks to
USDWs. In these deep-well injection scenarios, the added depth and
distance between the injection zone and overlying formations serve both
as a buffer allowing for pressure dissipation and as a zone for
monitoring that may detect any excursions (of the injectate) out of the
injection zone. Additional distance also allows trapping mechanisms,
including dissolution of CO2 in native fluids and
mineralization, to occur over time--thereby reducing risks that
CO2 may migrate from the injection zone and endanger USDWs.
Additionally, the depth and distance below the lowermost USDW allow the
potential for the presence of additional confining layers (between the
injection zone and overlying formations/USDWs).

C. Injection Depth Comments, Data, and Research

    EPA received a range of comments both in support of, and opposed
to, the proposed injection depth requirements for Class VI wells.
Comments Supporting the Proposed Injection Depth Requirements
    Comments that supported the proposed requirements indicated that
injection should be constrained to below the lowermost USDW (should not
be allowed above and/or between USDWs) because:
     SDWA requires the UIC program to promulgate regulations
(including injection depth requirements) that maximize USDW protection;
     Injection below the lowermost USDW is a long-standing
principle of UIC deep well injection;
     In many cases, injection below the lowermost USDW ensures
a greater distance between the injection zone and USDWs;
     GS is a new/unproven technology (at large scale) and, in
the early years of deployment, injection depth limitations are prudent.
These requirements could be relaxed in the future as information is
learned about GS injection;
     Keeping injection below the lowermost USDW will reduce the
likelihood of wells (e.g., water, mineral, and/or hydrocarbon
production) being drilled through a CO2 plume in the future.
    These comments and concerns about injection depth are further
supported by ongoing research, data, and activities related to water
use, availability, and planning; some of this research and data were
submitted to the proposed rule docket (e.g., EPA-HQ-OW-2008-0390-
0181.1). Water availability research in the United States indicates
that water treatment of higher salinity waters (in excess of the USDW
protectiveness threshold of 10,000 ppm TDS) may be more cost effective
than the cost of obtaining water rights or surface water elsewhere in
the area (Sengebush, 2008). Additionally, as technologies advance,
treatment of increasingly deeper and/or higher salinity waters may
become a common practice employed in many communities throughout the
US. Other studies support the need to consider long-term drinking water
protection and the confluence of population growth and constrained
water resources in parts of the US when developing injection depth
requirements (US Government Accountability Office, 2003; Davidson, et
al., 2008).
Comments Opposed to the Proposed Injection Depth Requirements
    Those opposed to the proposed requirements supported allowing
injection above and between USDWs. These commenters indicated that such
injection should be allowed under the following conditions and based on
the following arguments:
     At any depth without limitations;
     Based on site-specific information and in certain geologic
settings, where there are adequate confining systems above and below
the injection zone;
     Where formations have been exempted (for other injection
purposes) and/or where the formations are greater than 10,000 ppm TDS;
     Based on geographically delineated exemptions (e.g.,
specifically delineated formations, basins, or regions where injection
could occur at depths above/between USDW);
     Because many parts of the country will be excluded from GS
activities and as a result CCS deployment may be restricted (if this
requirement is maintained as written);
     Because Class II, Class III, and Class V operations are
already injecting above the lowermost USDW without any potential for
threats to underlying (or overlying) USDWs; and,
     Because there should not be a blanket prohibition for
Class VI GS wells.
    Research, information, and comments that support allowing injection
above and between USDWs have focused on climate change mitigation,
CO2 geologic storage capacity assessments, and current UIC
injection practices. Commenters interested in climate change mitigation
emphasized the role that GS will play in reducing greenhouse gas (GHG)
emissions while national GS capacity estimates focus on formations
irrespective of depth (above/below the lowermost USDW). Furthermore,
some specific research on CO2 injection for GS into various
formations including shallow, volcanic rocks such as flood basalts
(McGrail, et al., 2006) and coal seam injection (Dooley, et al., 2006;
IPCC, 2005; MIT 2007; White et al., 2005) illustrates the potential for
GS in these formations, but only if there is depth requirement
flexibility. Certain States have indicated that where USDWs are very
deep (e.g., 15,000 ft/4,572 meters and deeper) and layered (stratified)
these regions would become unavailable for large-scale GS projects
because injectors would not be able to comply with the current
injection depth (and well construction) requirements. These States
suggest that GS should be allowed in certain areas if a site-specific
demonstration can be made that USDWs will be protected.
    Some comments support the suggestion that current Class II, Class
III, and Class V injection activities occurring above and between USDWs
may serve as a viable analogue for GS injection depth requirements.
Class II and Class III owners and operators of sites where injection is
taking place above and between USDWs must identify and demonstrate
upper and lower impermeable confining units.

These confining units serve as barriers to fluid movement and pressure
and must ensure continuous injectate isolation, confinement, and USDW
protection. Identification of such units is conducted through analysis
of sonic and resistivity logs, drill stem tests, and wire line tests.

D. Evaluation of Concerns About Injection Depth for Class VI GS Wells

Discussion
    Under Section 1421 of the Safe Drinking Water Act (SDWA), UIC
regulations must prevent underground injection that endangers USDWs.
While EPA has met this statutory requirement in the past by requiring
injection below the lowermost USDW, for some of the injection
activities that may pose increased risks, the Act allows other
approaches as well (Kobelski, et al., 2005).
    In today's NODA, EPA is providing additional information on an
alternative for addressing injection depth in limited circumstances
where there are deep USDWs. EPA believes that a waiver process may
respond to the range of comments, both for and against the proposed
requirement that Class VI wells inject below the lowermost USDW. The
goals of this approach are to: (1) Provide flexibility to UIC Program
Directors and owner/operators that will undertake CO2
injection for GS; (2) respond to concerns about local and regional
geologic storage capacity limitations imposed by the proposed injection
depth requirements; (3) allow for a more site-specific assessment; (4)
accommodate injection into different formation types; and, (5) consider
the concept that CO2 injection for GS above and/or between
USDWs could be as safe and effective as injection below the lowermost
USDW as evidenced by past experiences with some Class II, III and V
injection wells. EPA believes this approach may additionally
accommodate requests for geographic flexibility while placing such
determinations at the State or Regional level. Lastly, the approach is
designed to acknowledge and accommodate comments and concerns about
drinking water resource availability and the potential/known future
needs, and to afford such water resources protection.
    EPA is considering a number of topics and the implications of the
various commenters' concerns related to this potential alternative as
follows:
    There have been a number of national GS capacity estimates
developed (e.g., by DOE's National laboratories, USGS, etc.). Some of
these assessments have broadly identified porous, permeable formations
that may receive and store CO2 at a range of depths beneath
the ground surface (Burruss, R.C., et al, 2009; DOE, 2007; Davidson et
al., 2008; MIT, 2007; Dooley, 2006). In developing injection depth
requirements, EPA acknowledges that these capacity estimates do not
directly address specific site suitability attributes that would be
identified through the UIC permitting site-characterization process.
Additionally, these formations (identified through capacity estimates)
may be stratified, stacked, or layered and in combination, their
cumulative capacity could be limited (i.e., less than assessed). In the
absence of such site-specific information, it is currently difficult to
identify what percentage of assessed national capacity is actually
suitable for GS. In addition, very small geologic storage sites, even
when aggregated within a given area, may not be conducive to/
appropriate for large-scale, commercial GS projects. However, the
approach described in this Notice allows for such a determination to be
made on a site-specific basis.
    Second, the alternative under consideration does not prohibit
injection into any specific formation types (e.g., basalts and/or coal
seams). It affords all formations equal treatment and allows specific
regions of the country the regulatory flexibility to determine if any
injection at a particular site and depth is the appropriate approach.
It will also help to manage injection in areas where there may be
multiple, stratified formations with significant assessed cumulative
capacity.
    Third, because the Agency believes that it is necessary to address
the specific, unique characteristics of Class VI injection (e.g., large
injection volumes, viscosity, and buoyancy) and the Agency does not
have information or data indicating that Class II operations are
entirely analogous to Class VI, large-scale injection, this alternative
allows Class VI injection depth considerations to be tailored for GS. A
number of dominant differences between Class II and Class VI operations
indicate that these well classes warrant different treatment. EPA
received comment during the public comment period supporting the need
for such a distinction. These differences include: the risk profiles
for these operations; the greater total injection volumes (of
CO2) for Class VI GS; and, differences in formation
pressures (potentially higher for GS), greater opportunities for
mobilization of constituents, and injection rates and operating
conditions.
    The alternative EPA is considering relies on the principle of site-
suitability for GS: injection zones/formations that have suitable upper
and lower confining units, appropriate lateral and vertical extent to
receive and contain the injected CO2, and an appropriate
management scheme to ensure that the water and other resources
contained within the injection zone will not be needed in the future.
The management scheme will also ensure that there is a strategy
developed to address future needs to access formations below the
injection zone.
    This approach would allow regulators and communities (e.g., States,
etc.) to assess the most appropriate injection depth for a given
project, in a given geographic or geologic area. It may also allow
communities, local, and State authorities to plan resource use
appropriately and, if necessary, circumvent the need to drill through a
CO2 filled zone/formation/plume to exploit resources (both
water and hydrocarbon) in or below the injection zone.
    Conversely, EPA is weighing the fact that this alternative would be
a divergence from the existing UIC deep-well injection requirements for
industrial and hazardous waste injection. It will result in greater
injection depth variability throughout the United States and may result
in emplacement of fluids by injection in closer proximity to USDWs than
would occur under the proposed requirements. Additionally, adoption of
this alternative could potentially add a new administrative burden to
UIC programs pursuing the waiver approach.
Consideration of New Approach
    Based on new information and data from comments received on the
proposed rule, the Agency is considering a waiver process to allow GS
injection above and between USDWs under specific conditions in lieu of
a blanket prohibition on injection above and between USDWs. The
proposed Class VI GS injection depth requirements would remain
unchanged but would allow an owner or operator seeking to inject above
and/or between USDWs to apply for a waiver from the proposed injection
depth requirements. The owner or operator would be required to
demonstrate to regulatory authorities that such injection can be
undertaken and completed in a manner that prevents fluid movement into
overlying (and underlying) USDWs, thereby preventing the endangerment
of public health from USDW contamination. This process would be
separate from aquifer exemptions and has no effect on 40 CFR parts
144.7 and 146.4.

    Under this alternative, an owner or operator applying for an
injection depth waiver would need to consider and submit additional,
specific information to the UIC Program Director and the Public Water
Supply Supervision (PWSS) Program Director for review prior to
completing a Class VI permit application. EPA is considering that such
information would likely include:
     Site characterization: Site characterization data will be
critical in determining appropriateness of a given formation and depth
for GS injection. The waiver application would need to demonstrate: (1)
Laterally continuous, impermeable confining units above and below the
injection zone adequate to prevent fluid movement and pressure buildup;
(2) A laterally continuous injection zone/formation with adequate
injectability, including sufficient porosity and permeability, and
appropriate soil-rock chemistry (so as to ensure that the injection
matrix is not dissolved as a result of injection); (3) An injection
zone and confining formations free of transmissive fractures and
faults; and, (4) A characterization of regional fracture properties and
a demonstration that such fractures will not interfere with injection,
serve as conduits, or endanger USDWs.
     AoR and corrective action: Due to the potential risk that
artificial penetrations pose as fluid/injectate conduits, the owner/
operator would need to map and identify all artificial penetrations in
the AoR that penetrate the injection zone, the upper and lower
confining zones, and all USDWs in the area. The purpose of this
demonstration would be to ensure that public water supplies, private
wells, and potential future water resources are identified and the
location of artificial penetrations into such formations are known and
these artificial penetrations can be appropriately plugged during the
permitting phase.
     Emergency and remedial response and financial
responsibility: The owner or operator would need to supplement the
emergency and remedial response plan (submitted as part of the waiver
application process and as part of the UIC Class VI permit) to ensure
protection of USDWs above and below the injection zone. The purpose of
this plan would be to explain that the owner or operator has considered
regional water resource issues and has explored alternative water
supplies or water treatment options to address unanticipated movement
of the injectate or formation fluids (e.g., CO2, brine, or
other fluids) into any overlying or underlying USDWs. The owner/
operator would also demonstrate sufficient, additional financial
responsibility to address any potential contamination of USDWs above or
below the injection zone.
    Upon compliance with the waiver process requirements, the owner/
operator would need to submit the information jointly to the UIC
Program Director and the PWSS Program Director. These Directors would
consider factors such as:
     The integrity of the upper and lower confining units
(certified by a Professional Geologist or a Professional Engineer);
     The suitability of the injection zone (e.g., lateral
continuity; lack of transmissive faults and fractures; knowledge of
current or planned artificial penetrations into it or formations below
the injection zone);
     The potential capacity of the geologic formation to
sequester CO2, accounting for the availability of
alternative injection sites;
     All other site characterization data, the proposed
emergency and remedial response plan, and a demonstration of financial
responsibility;
     Community needs, demands, and supply from drinking water
resources;
     Planned needs, potential and/or future use of USDWs and
non-USDWs in the area;
     Planned (or permitted) water, hydrocarbon, or mineral
resource exploitation potential of the proposed injection formation and
other formations both above and below the injection zone--to determine
if there are any plans to drill through the formation to access
resources in or beneath the proposed injection zone/formation;
     The proposed plan for securing alternative resources or
treating USDW formation waters in the event of contamination related to
the Class VI injection activity; and,
     Any other locally applicable considerations.
    The waiver may also be subject to local notice and public hearing.
Following a public hearing and waiver approval by both Program
Directors, the owner/operator may complete and submit the Class VI
permit application. The owner/operator may be required to comply with
additional requirements that apply as a result of receipt of the
waiver, designed to ensure the protection of USDWs both above and below
the injection zone. These requirements could include: more specific
construction and pre-operational testing requirements to reduce the
chances of upward fluid movement or inter-formational flow; enhanced
operating requirements such as more stringent injection pressure
limitations; a site-specific monitoring regime that includes increased
formation fluid and ground water sampling and monitoring above and
below the injection zone in concert with local water suppliers; seismic
plume tracking and monitoring of pressure changes above and below the
injection zone; supplemented financial responsibility and emergency and
remedial response requirements (consistent with those in the waiver);
and identification of the location of PWS and private drinking water
wells in developing and executing the post-injection site care and site
closure plan at the GS site.
Adoption of the Waiver Requirements
    Due to the range of concerns and comments related to the injection
depth requirements and the nature of the suggested waiver approval
procedure, EPA believes that adoption of any such injection depth
waiver process, as previously described, should be at the discretion of
the UIC Program Director. Because deep USDWs do not exist in every
State, EPA expects that not all States would choose to adopt the waiver
process. UIC Programs in such States may instead adopt and enforce the
proposed requirement that injection for GS be below the lowermost USDW.
    EPA also recognizes that States and UIC Directors have the
discretion to be more stringent in writing regulations for GS and/or
adopting Federal UIC requirements. As a result, States could include a
minimum injection depth requirement in their regulations or a Director
may impose such requirements on a site-specific basis.
    The Agency is requesting comment on the merits and possible
disadvantages of the injection depth waiver process. Specifically,
should an approach such as the one described in this Notice be
considered and if so, should there be additional, fewer, or different
elements? Some stakeholders are concerned about the risks associated
with the use of formations other than deep saline and depleted
reservoirs (e.g., coal seams, basalts, etc.). EPA is seeking comment on
whether the waiver process should apply to formations other than these.
    Additionally, the Agency is interested in:
    (1) Information on specific areas of the United States where
injection depth and USDW depth are of concern (including formation
depth, location, and assessed capacity; demonstrated confinement and GS
suitability; and, formation salinity/TDS) as determined by well-log
analyses, cross sections, and formation fluid analyses;

    (2) Data, information, and evidence from owners and operators
constructing and operating injection wells through existing
CO2 plumes to access resources (e.g., water, hydrocarbon,
etc.) below the injection zone and whether or not such operations are
safe and do not endanger USDWs; and,
    (3) Strategies that States, Tribes, and regions are considering to
manage competing GS and resource issues.

V. State Statutes, Regulations, and Activities Related to Geologic
Sequestration

    Throughout the regulatory development process for the Class VI
proposal, EPA has made it a priority to engage States and State
organizations. The EPA has honored a commitment to working with State
co-regulators to address regulatory issues related to GS through a
series of stakeholder and technical workshops, public hearings, and EPA
participation with national organizations including the Ground Water
Protection Council, the Interstate Oil and Gas Compact Commission, and
the American Association of State Geologists. EPA values coordination
with States and State co-regulators and will continue an open dialogue
as the Agency moves forward in the regulatory development process.
    EPA recognizes the complexity and importance of the States'
approaches to managing GS and does not want to unduly hinder State
activities as indicated in an April 2008 EPA letter to the States
(available in the docket for this regulatory action). The Agency is
aware that States are currently in various stages of developing
statutory frameworks, regulations, workgroups, technical guidance, and
strategies for addressing CCS and GS. Much of the expertise and
infrastructure currently exists within State UIC Programs. These
programs will form the foundation for managing GS wells. Additionally,
States can use multiple authorities beyond those afforded under the
SDWA and UIC regulations including surface access and land rights,
unitization of fields, pore space ownership, mineral rights, worker
safety and emergency preparedness, and maximization of State oil and
gas resource exploitation.
    At present, several States have published GS regulations, while a
number of other States are investigating and developing strategies to
address dual purpose injection wells (EOR/EGR and GS simultaneously).
Some States are using natural gas storage regulations as a platform for
developing these regulations. Additionally, as States develop
regulations and statutes, they are examining which State Agency can
most appropriately manage implementation for GS wells. EPA is
continuing to collaborate with States and will consider this
information as EPA develops guidance on the primacy application and
approval process for Class VI wells. Information about these State
activities may be found in the Docket for today's publication. EPA also
seeks comment on current State activities addressing GS. This
information will assist EPA in developing guidance for UIC program
implementers.

VI. Conclusions

    In conclusion, today's Notice supplements the proposed ``Federal
Requirements Under the Underground Injection Control (UIC) Program for
Carbon Dioxide (CO2) Geologic Sequestration (GS) Wells'' of
July 25, 2008 (73 FR 43492), presents new data and information, and
requests public comment on related issues that have evolved in response
to comments on the original proposal. This Notice contains preliminary
field data from Department of Energy-sponsored Regional Carbon
Sequestration Partnership projects, the results of GS-related studies
conducted by the Lawrence Berkeley National Laboratory, and additional
GS related research. Today's Notice also discusses comments and
presents an alternative the Agency is considering related to the
proposed injection depth requirements.

VII. References

Birkholzer, J.T., Q. Zhou, and C.F. Tsang. 2009. Large-Scale Impact
of CO2 Storage in Deep Saline Aquifers: A Sensitivity
Study on the Pressure Response in Stratified Systems. International
Journal of Greenhouse Gas Control, 3(2), 181-194.
Birkholzer, J., J. Apps, L. Zheng, Y. Zhang, T. Xu, and C.-F. Tsang.
2008a. Research Project on CO2 Geological Storage and
Groundwater Resources: Water Quality Effects Caused by
CO2 Intrusion into Shallow Groundwater. Technical Report,
LBNL-1251E, October 2008.
Birkholzer, J., Q. Zhou, K. Zhang, P. Jordan, J. Rutqvist, and C.-F.
Tsang. 2008b. Research Project on CO2 Geological Storage
and Groundwater Resources: Large-Scale Hydrological Evaluation and
Modeling of the Impact on Groundwater Systems. NETL Project Annual
Report, October 1, 2007 to September 30, 2008.
Burruss, R.C., Brennan, S.T., Freeman, P.A., Merrill, M.D., Ruppert,
L.F., Becker, M.F., Herkelrath, W.N., Kharaka, Y.K., Neuzil, C.E.,
Swanson, S.M., Cook, T.A., Klett, T.R., Nelson, P.H., and C.J.
Schenk. 2009. Development of a Probabilistic Assessment Methodology
for Evaluation of Carbon Dioxide Storage: US Geological Survey Open-
File Report 2009-1035, 81 p. http://pubs.usgs.gov/of/2009/1035/.
Davidson, C.L., J.J. Dooley, and R.T. Dahowski. 2008. Assessing the
Impacts of Future Demand for Saline Groundwater on Commercial
Deployment of CCS in the United States. 9th International Conference
on Greenhouse Gas Control Technologies, (November 2008). Washington,
DC.
Dooley, J.J., R.T. Dahowski, C.L. Davidson, M.A. Wise, N. Gupta,
S.H. Kim, and E.L. Malone. 2006. Carbon Dioxide Capture and Geologic
Storage: A Core Element of a Global Energy Technology Strategy to
Address Climate Change. A Technology Report from the Second Phase of
the Global Energy Technology Strategy Program. April, 2006.
Friedman, S. J. 2007. Geological Carbon Dioxide Sequestration.
Elements, 3, 179-184.
Holloway, S. 2001. Storage of Fossil Fuel-Derived Carbon Dioxide
Beneath the Surface of the Earth. Annual Review of Energy and the
Environment, 26, 145-66.
IPCC. 2005. IPCC Special Report on Carbon Dioxide Capture and
Storage. Prepared by Working Group III of the Intergovernmental
Panel on Climate Change. Metz, B., O. Davidson, H. C. de Coninck, M.
Loos, and L. A. Meyer (eds.). New York: Cambridge University Press.
Kobelski, B.J., R.E. Smith, and A.L. Whitehurst. 2005. An
Interpretation of the Safe Drinking Water Act's ``Non-Endangerment''
Standard for the Underground Injection Control (UIC) Program. In
Developments in Water Science: Underground Injection Science and
Technology, 52, 39-43.
McGrail, B.P., H.T. Schaef, A.M. Ho, Y. Chien, J.J. Dooley, and C.L.
Davidson. 2006. Potential for Carbon Dioxide Sequestration in Flood
Basalts. Journal of Geophysical Research, III B12201.
MIT. 2007. Massachusetts Institute of Technology. The Future of
Coal--Options for a Carbon Constrained World.
Nicot, J.P. 2008. Evaluation of Large-Scale Carbon Storage on Fresh-
Water Section of Aquifers: A Texas Study. International Journal of
Greenhouse Gas Control, 2(4), 582-593.
Schnaar, G. and D. Digiulio. 2009. Computational Modeling of the
Geologic Sequestration of Carbon Dioxide. Vadose Zone Journal, 8(2),
389-403.
Sengebush, R.M. 2008. Deep Brackish Water Considered for New Mexico
Development. Southwest Hydrology, March/April 2008, 8.
Tsang, C.-F., J. Birkholzer and J. Rutqvist. 2008. A Comparative
Review of Hydrologic Issues Involved in Geologic Storage of
CO2 and Injection Disposal of Liquid Waste. Environmental
Geology, 54, 1723-1737.
U.S. DOE. 2007 Carbon Sequestration Atlas of the United States and
Canada. US Department of Energy, Office of Fossil Energy, national
Energy Technology Laboratory. March, 2007. http://www.netl.doe.gov/
technologies/carbon_seq/refshelf/atlas/.
U.S. Government Accountability Office. 2003. Freshwater Supply:
States' Views

of House Federal Agencies Could Help Them Meet the Challenges of
Expected Shortages (GAO-03-514). July, 2003.
van der Meer, L.G.H. and F. Yavuz. 2008. CO2 Storage
Capacity Calculations for the Dutch Subsurface. 9th International
Conference on Greenhouse Gas Control Technologies, (November 2008).
Washington, DC.
White, C.M., D.H. Smith, K.L. Jones, A.L. Goodman, S.A. Jikich, R.B.
LaCount, S.B. DuBose, E. Ozdemir, B.I. Morsi, and k.T. Schroeder.
2005. Sequestration of Carbon Dioxide In Coal With Enhanced Coalbed
Methane Recovery--A Review. Energy Fuels, 19(3), 659-724.
Zhou, Q., J.T. Birkholzer, C.F. Tsang, and J. Rutqvist. 2008. A
Method for Quick Assessment of CO2 Storage Capacity in
Closed and Semi-Closed Saline Formations. International Journal of
Greenhouse Gas Control, 2(4), 626-639.

    Dated: August 21, 2009.
Peter S. Silva,
Assistant Administrator, Office of Water.
[FR Doc. E9-20920 Filed 8-28-09; 8:45 am]

BILLING CODE 6560-50-P