[Federal Register: June 21, 2010 (Volume 75, Number 118)]
[Proposed Rules]
[Page 35127-35264]
[DOCID:fr21jn10-29]

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Part II

Environmental Protection Agency

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40 CFR Parts 257, 261, 264 et al.

Hazardous and Solid Waste Management System; Identification and Listing
of Special Wastes; Disposal of Coal Combustion Residuals From Electric
Utilities; Proposed Rule

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 257, 261, 264, 265, 268, 271 and 302

[EPA-HQ-RCRA-2009-0640; FRL-9149-4]
RIN-2050-AE81

Hazardous and Solid Waste Management System; Identification and
Listing of Special Wastes; Disposal of Coal Combustion Residuals From
Electric Utilities

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA or Agency) is
proposing to regulate for the first time, coal combustion residuals
(CCRs) under the Resource Conservation and Recovery Act (RCRA) to
address the risks from the disposal of CCRs generated from the
combustion of coal at electric utilities and independent power
producers. However, the Agency is considering two options in this
proposal and, thus, is proposing two alternative regulations. Under the
first proposal, EPA would reverse its August 1993 and May 2000 Bevill
Regulatory Determinations regarding coal combustion residuals (CCRs)
and list these residuals as special wastes subject to regulation under
subtitle C of RCRA, when they are destined for disposal in landfills or
surface impoundments. Under the second proposal, EPA would leave the
Bevill determination in place and regulate disposal of such materials
under subtitle D of RCRA by issuing national minimum criteria. Under
both alternatives EPA is proposing to establish dam safety requirements
to address the structural integrity of surface impoundments to prevent
catastrophic releases.
    EPA is not proposing to change the May 2000 Regulatory
Determination for beneficially used CCRs, which are currently exempt
from the hazardous waste regulations under Section 3001(b)(3)(A) of
RCRA. However, EPA is clarifying this determination and seeking comment
on potential refinements for certain beneficial uses. EPA is also not
proposing to address the placement of CCRs in mines, or non-minefill
uses of CCRs at coal mine sites in this action.

DATES: Comments must be received on or before September 20, 2010. EPA
will provide an opportunity for a public hearing on the rule upon
request. Requests for a public meeting should be submitted to EPA's
Office of Resource Conservation and Recovery by July 21, 2010. See the
FOR FURTHER INFORMATION CONTACT section for contact information. Should
EPA receive requests for public meetings within this timeframe, EPA
will publish a document in the Federal Register providing the details
of such meetings.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
RCRA-2009-0640, by one of the following methods:
     http://www.regulations.gov: Follow the on-line
instructions for submitting comments.
     E-mail: Comments may be sent by electronic mail (e-mail)
to<EMAIL_ADDRESS>Attention Docket ID No. EPA-HQ-RCRA-2009-0640.
In contrast to EPA's electronic public docket, EPA's e-mail system is
not an ``anonymous access'' system. If you send an e-mail comment
directly to the Docket without going through EPA's electronic public
docket, EPA's e-mail system automatically captures your e-mail address.
E-mail addresses that are automatically captured by EPA's e-mail system
are included as part of the comment that is placed in the official
public docket, and made available in EPA's electronic public docket.
     Fax: Comments may be faxed to<PHONE_NUMBER>; Attention
Docket ID No. EPA-HQ-RCRA-2009-0640.
     Mail: Send your comments to the Hazardous Waste Management
System; Identification and Listing of Special Wastes; Disposal of Coal
Combustion Residuals From Electric Utilities Docket, Attention Docket
ID No., EPA-HQ-RCRA-2009-0640, Environmental Protection Agency,
Mailcode: 5305T, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
Please include a total of two copies.
     Hand Delivery: Deliver two copies of your comments to the
Hazardous Waste Management System; Identification and Listing of
Special Wastes; Disposal of Coal Combustion Residuals From Electric
Utilities Docket, Attention Docket ID No., EPA-HQ-RCRA-2009-0640, EPA/
DC, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington, DC
20460. Such deliveries are only accepted during the Docket's normal
hours of operation, and special arrangements should be made for
deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-RCRA-
2009-0640. 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. 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. For additional information about EPA's public
docket, visit the EPA Docket Center homepage at http://www.epa.gov/
epahome/dockets.htm. For additional instructions on submitting
comments, go to the SUPPLEMENTARY INFORMATION section of this document.
    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 Hazardous Waste
Management System; Identification and Listing of Special Wastes;
Disposal of Coal Combustion Residuals From Electric Utilities Docket,
EPA/DC, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington,
DC 20460. This Docket Facility is open from 8:30 a.m. to 4:30 p.m.,
Monday through Friday, excluding legal holidays. The Docket telephone
number is<PHONE_NUMBER>. 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>.

FOR FURTHER INFORMATION CONTACT: Alexander Livnat, Office of Resource
Conservation and Recovery, Environmental Protection Agency, 5304P;
telephone number:<PHONE_NUMBER>; fax number:<PHONE_NUMBER>; e-mail
address<EMAIL_ADDRESS>or Steve Souders, Office of Resource
Conservation and Recovery, Environmental Protection Agency, 5304P;
telephone number:<PHONE_NUMBER>; fax number:<PHONE_NUMBER>; e-mail
address<EMAIL_ADDRESS>For technical information on the CERCLA
aspects of this rule, contact Lynn Beasley, Office of Emergency
Management, Regulation and Policy Development Division (5104A), U.S.
Environmental Protection Agency, 1200 Pennsylvania Avenue, NW.,
Washington, DC 20460, [E-mail address and telephone number:
<EMAIL_ADDRESS>(202-564-1965).]
    For more information on this rulemaking please visit http://
www.epa.gov/epawaste/nonhaz/industrial/special/fossil/index.htm.

SUPPLEMENTARY INFORMATION:

A. Does this action apply to me?

    The proposed rule would apply to all coal combustion residuals
(CCRs) generated by electric utilities and independent power producers.
However, this proposed rule does not address the placement of CCRs in
minefills. The U. S. Department of Interior (DOI) and EPA will address
the management of CCRs in minefills in a separate regulatory action(s),
consistent with the approach recommended by the National Academy of
Sciences, recognizing the expertise of DOI's Office of Surface Mining
Reclamation and Enforcement in this area.\1\ In addition, under either
alternative proposal, EPA is not proposing to affect the current status
of coal combustion residuals that are beneficially used.\2\ (See
section IV. D for further details on proposed clarifications of
beneficial use.) CCRs from non-utility boilers burning coal are not
included within today's proposed rule. EPA will decide on an
appropriate action for these wastes after completing this rulemaking
effort.
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    \1\ The National Research Council (NRC) Committee on Mine
Placement of Coal Combustion Wastes stated: ``The committee believes
that OSM and its SMCRA state partners should take the lead in
developing new national standards for CCR use in mines because the
framework is in place to deal with mine-related issues.'' National
Academy of Sciences. Managing Coal Combustion Residues in Mines; The
National Academies Press, Washington, DC, 2006.
    \2\ The NRC committee recommended ``that secondary uses of CCRs
that pose minimal risks to human health and the environment be
strongly encouraged.'' Ibid.
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    The proposed rule may affect the following entities: electric
utility facilities and independent power producers that fall under the
North American Industry Classification System (NAICS) code 221112, and
hazardous waste treatment and disposal facilities that fall under NAICS
code 562211. The industry sector(s) identified above may not be
exhaustive; other types of entities not listed could also be affected.
The Agency's aim is to provide a guide for readers regarding those
entities that potentially could be affected by this action. To
determine whether your facility, company, business, organization, etc.,
is affected by this action, you should refer to the applicability
criteria contained in section IV of this preamble. If you have any
questions regarding the applicability of this action to a particular
entity, consult the person listed in the preceding FOR FURTHER
INFORMATION CONTACT section.

B. What should I consider as I prepare my comments for EPA?

    1. Submitting confidential business information (CBI). Do not
submit information that you consider to be CBI through http://
www.regulations.gov or by e-mail. Send or deliver information
identified as CBI only to the following address: RCRA CBI Document
Control Officer, Office of Resource Conservation and Recovery (5305P),
U.S. EPA, 1200 Pennsylvania Avenue, NW., Washington DC 20460, Attention
Docket No, EPA-HQ-RCRA-2009-0640. You may claim information that you
submit to EPA as CBI by marking any part or all of the information as
CBI (if you submit CBI on a disk or CD ROM, mark the outside of the
disk or CD ROM as CBI and then identify electronically within the disk
or CD ROM the specific information that is claimed as CBI). Information
so marked will not be disclosed, except in accordance with the
procedures set forth in 40 CFR part 2. In addition to one complete
version of the comment that includes information claimed as CBI, a copy
of the comment that does not contain the information claimed as CBI
must be submitted for inclusion in the public docket. If you submit the
copy that does not contain CBI on disk or CD ROM, mark the outside of
the disk or CD ROM clearly that it does not contain CBI. Information
not marked as CBI will be included in the public docket and EPA's
electronic public docket without prior notice. If you have questions
about CBI or the procedures for claiming CBI, please contact: LaShan
Haynes, Office of Resource Conservation and Recovery (5305P), U.S.
Environmental Protection Agency, 1200 Pennsylvania Avenue, NW.,
Washington DC 20460-0002, telephone<PHONE_NUMBER>, e-mail address
<EMAIL_ADDRESS>    2. Tips for Preparing Your Comments. When submitting comments,
remember to:
     Identify the rulemaking by docket number and other
identifying information (subject heading, Federal Register date and
page number).
     Follow directions--The Agency may ask you to respond to
specific questions or organize comments by referencing a Code of
Federal Regulations (CFR) part or section number.
     Explain why you agree or disagree, suggest alternatives,
and substitute language for your requested changes, and explain your
interest in the issue you are attempting to address.
     Describe any assumptions and provide any technical
information and/or data that you used.
     If you estimate potential costs or burdens, explain how
you arrived at your estimate in sufficient detail to allow for it to be
reproduced.
     Provide specific examples to illustrate your concerns, and
suggest alternatives.
     Explain your views as clearly as possible.
     Make sure to submit your comments by the comment period
deadline identified.
    3. Docket Copying Costs. The first 100-copied pages are free.
Thereafter, the charge for making copies of Docket materials is 15
cents per page.

C. Definitions, Abbreviations and Acronyms Used in This Preamble (Note:
Any term used in this proposed rulemaking that is not defined in this
section will either have its normal dictionary meaning, or is defined
in 40 CFR 260.10.)

    Acre-foot means the volume of one acre of surface area to a depth
of one foot.
    Beneficial Use of Coal Combustion Products (CCPs) means the use of
CCPs that provides a functional benefit; replaces the use of an
alternative material, conserving natural resources that would otherwise
need to be obtained through practices such as extraction; and meets
relevant product specifications and regulatory standards (where these
are available). CCPs that are used in excess quantities (e.g., the
field-applications of FGD gypsum in amounts that exceed scientifically-
supported quantities required for enhancing soil properties and/or crop

yields), placed as fill in sand and gravel pits, or used in large scale
fill projects, such as for restructuring the landscape, are excluded
from this definition.
    Boiler slag means the molten bottom ash collected at the base of
slag tap and cyclone type furnaces that is quenched with water. It is
made up of hard, black, angular particles that have a smooth, glassy
appearance.
    Bottom ash means the agglomerated, angular ash particles, formed in
pulverized coal furnaces that are too large to be carried in the flue
gases and collect on the furnace walls or fall through open grates to
an ash hopper at the bottom of the furnace.
    CCR Landfill means a disposal facility or part of a facility where
CCRs are placed in or on land and which is not a land treatment
facility, a surface impoundment, an underground injection well, a salt
dome formation, a salt bed formation, an underground mine, a cave, or a
corrective action management unit. For purposes of this proposed rule,
landfills also include piles, sand and gravel pits, quarries, and/or
large scale fill operations. Sites that are excavated so that more coal
ash can be used as fill are also considered CCR landfills.
    CCR Surface Impoundment or impoundment means a facility or part of
a facility which is a natural topographic depression, man-made
excavation, or diked area formed primarily of earthen materials
(although it may be lined with man-made materials), which is designed
to hold an accumulation of CCRs containing free liquids, and which is
not an injection well. Examples of CCR surface impoundments are
holding, storage, settling, and aeration pits, ponds, and lagoons. CCR
surface impoundments are used to receive CCRs that have been sluiced
(flushed or mixed with water to facilitate movement), or wastes from
wet air pollution control devices, often in addition to other solid
wastes.
    Cenospheres are lightweight, inert, hollow spheres comprised
largely of silica and alumina glass.
    Coal Combustion Products (CCPs) means fly ash, bottom ash, boiler
slag, or flue gas desulfurization materials, that are beneficially
used.
    Coal Combustion Residuals (CCRs) means fly ash, bottom ash, boiler
slag, and flue gas desulfurization materials destined for disposal.
CCRs are also known as coal combustion wastes (CCWs) and fossil fuel
combustion (FFC) wastes, when destined for disposal.
    Electric Power Sector (Electric Utilities and Independent Power
Producers) means that sector of the power generating industry that
comprises electricity-only and combined-heat-and-power (CHP) plants
whose primary business is to sell electricity, or electricity and heat,
to the public.
    Existing CCR Landfill means a landfill which was in operation or
for which construction commenced prior to the effective date of the
final rule. A CCR landfill has commenced construction if the owner or
operator has obtained the Federal, State and local approvals or permits
necessary to begin physical construction; and either
    (1) A continuous on-site, physical construction program has begun;
or
    (2) The owner or operator has entered into contractual
obligations--which cannot be cancelled or modified without substantial
loss--for physical construction of the CCR landfill to be completed
within a reasonable time.
    Existing CCR Surface Impoundment means a surface impoundment which
was in operation or for which construction commenced prior to the
effective date of the final rule. A CCR surface impoundment has
commenced construction if the owner or operator has obtained the
Federal, State and local approvals or permits necessary to begin
physical construction; and either
    (1) A continuous on-site, physical construction program has begun;
or
    (2) The owner or operator has entered into contractual
obligations--which can not be cancelled or modified without substantial
loss--for physical construction of the CCR surface impoundment to be
completed within a reasonable time.
    Flue Gas Desulfurization (FGD) material means the material produced
through a process used to reduce sulfur dioxide (SO2)
emissions from the exhaust gas system of a coal-fired boiler. The
physical nature of these materials varies from a wet sludge to a dry
powdered material, depending on the process, and their composition
comprises either sulfites, sulfates or a mixture thereof.
    Fly ash means the very fine globular particles of silica glass
which is a product of burning finely ground coal in a boiler to produce
electricity, and is removed from the plant exhaust gases by air
emission control devices.
    Hazard potential means the possible adverse incremental
consequences that result from the release of water or stored contents
due to failure of a dam (or impoundment) or mis-operation of the dam or
appurtenances.\3\
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    \3\ The Hazard Potential Classification System for Dams was
developed by the U.S. Army Corps of Engineers for the National
Inventory of Dams (see https://rsgis.crrel.usace.army.mil/apex/
f?p=397:1:913698079375545). Hazard potential ratings do not provide
an estimate of the probability of failure or mis-operation, but
rather what the consequences of such a failure or mis-operation
would be.
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    High hazard potential surface impoundment means a surface
impoundment where failure or mis-operation will probably cause loss of
human life.
    Significant hazard potential surface impoundment means a surface
impoundment where failure or mis-operation results in no probable loss
of human life, but can cause economic loss, environment damage,
disruption of lifeline facilities, or impact other concerns.
    Low hazard potential surface impoundment means a surface
impoundment where failure or mis-operation results in no probable loss
of human life and low economic and/or environmental losses. Losses are
principally limited to the surface impoundment owner's property.
    Less than low hazard potential surface impoundment means a surface
impoundment not meeting the definitions for High, Significant, or Low
Hazard Potential.
    Independent registered professional engineer or hydrologist means a
scientist or engineer who is not an employee of the owner or operator
of a CCR landfill or surface impoundment who has received a
baccalaureate or post-graduate degree in the natural sciences or
engineering and has sufficient training and experience in groundwater
hydrology and related fields as may be demonstrated by state
registration, professional certifications, or completion of accredited
university programs that enable that individual to make sound
professional judgments regarding groundwater monitoring, contaminant
fate and transport, and corrective action.
    Lateral expansion means a horizontal expansion of the waste
boundaries of an existing CCR landfill, or existing CCR surface
impoundment made after the effective date of the final rule.
    Maximum Contaminant Level (MCL) means the highest level of a
contaminant that is allowed in drinking water under the Safe Drinking
Water Act (SDWA). MCLs are set as close to the MCL goals as feasible
using the best available treatment technology and taking cost into
consideration. MCLs are enforceable standards for drinking water.
    Minefill means a project involving the placement of CCRs in coal
mine voids for use as fill, grouting, subsidence control, capping, mine
sealing, and

treating acid mine drainage, whether for purposes of disposal or for
beneficial use, such as mine reclamation.
    Natural water table means the natural level at which water stands
in a shallow well open along its length and penetrating the surficial
deposits just deeply enough to encounter standing water at the bottom.
This level is uninfluenced by groundwater pumping or other engineered
activities.
    Organosilanes are organic compounds containing at least one carbon
to silicon bond, and are typically used to promote adhesion.
    Potential damage case means those cases with documented MCL
exceedances that were measured in ground water beneath or close to the
waste source. In these cases, while the association with CCRs has been
established, the documented exceedances had not been demonstrated at a
sufficient distance from the waste management unit to indicate that
waste constituents had migrated to the extent that they could cause
human health concerns.
    Pozzolanic material means primarily vitreous siliceous materials,
such as many types of CCRs that, when combined with calcium hydroxide
and in the presence of water, exhibit cementitious properties.
    Proven damage case means those cases with (i) Documented
exceedances of primary maximum contaminant levels (MCLs) or other
health-based standards measured in ground water at sufficient distance
from the waste management unit to indicate that hazardous constituents
have migrated to the extent that they could cause human health
concerns, and/or (ii) where a scientific study provides documented
evidence of another type of damage to human health or the environment
(e.g., ecological damage), and/or (iii) where there has been an
administrative ruling or court decision with an explicit finding of
specific damage to human health or the environment. In cases of co-
management of CCRs with other industrial waste types, CCRs must be
clearly implicated in the reported damage.
    Sand and gravel pit, and/or quarry means an excavation for the
commercial extraction of aggregate for use in construction projects.
CCRs have historically been used to fill sand and gravel pits and
quarries. CCRs are not known to be used to fill metal mines.
    Secondary Drinking Water Standards are non-enforceable federal
guidelines regarding cosmetic effects (such as tooth or skin
discoloration) or aesthetic effects (such as taste, odor, or color) of
drinking water.
    Special Wastes means any of the following wastes that are managed
under the modified subtitle C requirements: CCRs destined for disposal.
    Surface Water means all water naturally open to the atmosphere
(rivers, lakes, reservoirs, ponds, streams, impoundments, seas,
estuaries, etc.).
    Uniquely associated wastes means low-volume wastes other than those
defined as CCRs that are related to the coal combustion process.
Examples of uniquely associated wastes are precipitation runoff from
coal storage piles at the electric utility, waste coal or coal mill
rejects that are not of sufficient quality to burn as a fuel, and
wastes from cleaning boilers used to generate steam.

CCPs Coal Combustion Products
CCRs Coal Combustion Residuals
CFR Code of Federal Regulations
CERCLA Comprehensive Environmental Response, Compensation, and
Liability Act
EPA U.S. Environmental Protection Agency
EPCRA Emergency Planning and Community Right-to-Know Act
MCL Maximum Contaminant Level
m/L milligrams per liter
NPDES National Pollutant Discharge Elimination System
NRC National Response Center
PDWS Primary Drinking Water Standard
OSM Office of Surface Mining Reclamation and Enforcement, U.S.
Department of the Interior
RCRA Resource Conservation and Recovery Act (42 USCA 6901)
RQ Reportable Quantity
SDWS Secondary Drinking Water Standard
SMCRA Surface Mining Control and Reclamation Act
[mu]g/L micrograms per liter
WQC Federal water quality criteria

D. The Contents of This Preamble Are Listed in the Following Outline

I. Background
    A. Why is EPA proposing two options?
    1. Basis of Why EPA Is Proceeding With Today's Co-Proposals
    2. Brief Description of Today's Co-Proposals
    3. Summary of Estimated Regulatory Costs and Benefits
    B. What is the statutory authority for this action?
    C. Regulation of Wastes Under RCRA Subtitle C
    D. Regulation of Solid Wastes Under RCRA Subtitle D
    E. Summary of the 1993 and 2000 Regulatory Determinations
    F. What are CCRs?
    1. Chemical Constituents in CCRs
    2. Recent EPA Research on Constituent Leaching From CCRs
    G. Current Federal Regulations or Standards Applicable to the
Placement of CCRs in Landfills and Surface Impoundments
II. New Information on the Placement of CCRs in Landfills and
Surface Impoundments
    A. New Developments Since the May 2000 Regulatory Determination
    B. CCR Risk Assessment
    C. Damage Cases
III. Overview and Summary of the Bevill Regulatory Determination and
the Proposed Subtitle C and Subtitle D Regulatory Options
    A. Summary of Subtitle C Proposal
    B. Summary of Subtitle D Proposal
IV. Bevill Regulatory Determination Relating to CCRs From Electric
Utilities
    A. Basis for Reconsideration of May 2000 Regulatory
Determination
    B. RCRA Section 8002(n) Study Factors Environmental Benefits
    C. Preliminary Bevill Conclusions and Impact of Reconsideration
    D. EPA Is Not Reconsidering the Regulatory Determination
Regarding Beneficial Use
    1. Why is EPA not proposing to change the determination that
CCRs that are beneficially used do not warrant federal regulation?
    2. What constitutes beneficial use?
    3. Disposal of CCRs in Sand and Gravel Pits and Large Scale Fill
Operations Is Not Considered a Beneficial Use
    4. Issues Associated With Unencapsulated Beneficial Uses
    E. Placement of CCRs in Minefilling Operations
    F. EPA Is Not Proposing To Revise the Bevill Determination for
CCRs Generated by Non-Utilities
V. Co-Proposed Listing of CCRs as a Special Waste Under RCRA
Subtitle C and Special Requirements for Disposal of CCRs Generated
by Electric Utilities
    A. What is the basis for listing CCRs as a special waste?
    1. Criteria for Listing CCRs as a Special Waste and Background
on 2010 Risk Assessment
    B. Background on EPA's 2010 Risk Assessment
    1. Human Health Risks
    2. Ecological Risks
    C. Consideration of Individual Listing Criteria
    1. Toxicity--Factor (i)
    2. Concentration of Constituents in Waste--Factor (ii)
    3. Migration, Persistence, Degradation, and Bioaccumulation--
Factors (iii), (iv), (v), and (vi)
    4. Plausible Types of Mismanagement, Quantities of the Waste
Generated, Nature and Severity of Effects From Mismanagement--
Factors (vii), (viii) and (ix)
    5. Action Taken by Other Governmental Agencies or Regulatory
Programs Based on the Health or Environmental Hazard Posed by the
Waste or Waste Constituent--Factor (x)
    6. Other Factors--Factor (xi)
VI. Summary of the Co-Proposed Subtitle C Regulations
    A. Special Waste Listing
    B. Proposed Special Requirements for CCRs

    1. Modification of Technical Standards Under 3004(x)
    i. Modification of CCR Landfills and Surface Impoundments From
the Section 3004(o) Liner and Leak Detection Requirements
    ii. Fugitive Dust Controls
    iii. Special Requirements for Stability of CCR Surface
Impoundments
    iv. Wet-Handling of CCRs, Closure, and Interim Status for
Surface Impoundments
    v. Proposed Land Disposal Restrictions
    2. Proposed Treatment Standards for Non-Wastewaters (Dry CCRs)
    3. Proposed Treatment Standards for Wastewaters (Wet-Handled
CCRs)
    4. Effective Date of the LDR Prohibitions
    C. Applicability of Subtitle C Regulations
    D. CERCLA Designation and Reportable Quantities
    1. Reporting Requirements
    2. Basis for RQs and Adjustments
    3. Application of the CERCLA Mixture Rule to Listed CCR
    4. Correction of Table of Maximum Observed Constituent
Concentrations Identified by EPA
    E. Listing of CCR as Special Wastes To Address Perceived Stigma
Issue
VII. How would the proposed subtitle C requirements be implemented?
    A. Effective Dates
    B. What are the requirements with which facilities must comply?
    1. Generators and Transporters
    2. Treatment, Storage, and Disposal Facilities (TSDs)
    C. RCRA Section 3010 Notification
    D. Permit Requirements
    1. Facilities Newly Subject to RCRA Permit Requirements
    2. Existing Interim Status Facilities
    3. Permitted Facilities
    E. Requirements in 40 CFR Parts 264 and 265
VIII. Impacts of a Subtitle C Rule on State Authorization
    A. Applicability of the Rule in Authorized States
    B. Effect on State Authorization
IX. Summary of the Co-Proposal Regulating CCRs Under Subtitle D
Regulations
    A. Overview and General Issues
    1. Regulatory Approach
    2. Notifications
    B. Section-by-Section Discussion of RCRA Subtitle D Criteria
    1. Proposed Modifications to Part 257, Subpart A
    2. General Provisions
    3. Definitions
    4. Location Restrictions
    5. Design Requirements
    6. Operating Requirements
    7. Ground Water Monitoring/Corrective Action
    8. Closure and Post-Closure Care
    9. Financial Assurance
    10. Off-Site Disposal
    11. Alternative RCRA Subtitle D Approaches
X. How would the proposed subtitle D regulations be implemented?
    A. Effective Dates
    B. Implementation and Enforcement of Subtitle D Requirements
XI. Impact of a Subtitle D Regulation on State Programs
XII. Impacts of the Proposed Regulatory Alternatives
    A. What are the economic impacts of the proposed regulatory
alternatives?
    B. Benefits Not Quantified in the RIA
    1. Non-Quantified Plant and Wildlife Protection Benefits
    2. Non-Quantified Surface Water Protection Benefits
    3. Non-Quantified Ambient Air Protection Benefits
    C. Comparison of Costs to Benefits for the Regulatory
Alternatives
    D. What are the potential environmental and public health
impacts of the proposed regulatory alternatives?
    1. Environmental and Public Health Impacts Estimated in the RIA
    2. Environmental and Public Health Impacts Not Estimated in the
RIA
XIII. Other Alternatives EPA Considered
XIV. Is the EPA soliciting comments on specific issues?
XV. Executive Orders and Laws Addressed in This Action
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health & Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
APPENDIX to the Preamble: Documented Damages From CCR Management
Practices

I. Background

A. Why is EPA proposing two options?

1. Basis of Why EPA Is Proceeding With Today's Co-Proposals
    EPA is revisiting its regulatory determination for CCRs under the
Bevill amendment. This decision is driven in part by the failure of a
surface impoundment retaining wall in Kingston, TN in December 2009.
Deciding upon the appropriate course of action to address over 100
million tons per year of CCRs is an extremely important step. In
developing this proposal, EPA conducted considerable data gathering and
analysis. While the public was able to comment on significant portions
of our analyses in August 2007, as part of a Notice of Data
Availability, there are differing views regarding the meaning of EPA's
information and what course of action EPA should take. In part, the
differing views are fueled by the complex data, analyses, legislation,
implications of available options, possible unintended consequences,
and a decision process, all of which pose considerations that could
justify EPA selecting a RCRA subtitle C approach or selecting a RCRA
subtitle D approach.
    Deciding whether or not to maintain the Bevill exemption for CCRs,
entails an evaluation of the eight RCRA Section 8002(n) study factors:
     Source and volumes of CCRs generated per year
     Present disposal and utilization practices
     Potential danger, if any, to human health and the
environment from the disposal and reuse of CCRs
     Documented cases in which danger to human health or the
environment from surface runoff or leachate has been proved
     Alternatives to current disposal methods
     The cost of such alternatives
     The impact of the alternatives on the use of coal and
other natural resources
     The current and potential utilization of CCRs

Ultimately, the approach selected will need to ensure that catastrophic
releases such as occurred at the Tennessee Valley Authority's (TVA's)
Kingston, Tennessee facility do not occur and that other types of
damage cases associated with CCR surface impoundments and landfills are
prevented. Thus, this process requires EPA to balance the eight
factors, which ultimately rests on a policy judgment. This is further
complicated in this case because the facts identified under each of the
individual factors are even subject to widely varying perspectives. For
example, in considering the alternatives to current disposal methods,
some claim that RCRA subtitle C would significantly lessen beneficial
use while others see beneficial use expanding as disposal becomes more
costly; some see damage cases as substantial, while others note very
few incidences of significant off-site contamination.
    Given the inherently discretionary nature of the decision, the
complexities of the scientific analyses, and the controversy of the
issue, EPA wants to ensure that the ultimate decision is based on the
best available data, and is taken with the fullest possible extent of
public input. As discussed in section IV in greater detail, there are a
number of issues on which additional or more recent information would
be useful in

allowing the Agency to reach a final decision. In the absence of this
information, EPA has not yet reached a conclusion as to how to strike
the appropriate balance among these eight factors and so is presenting
two proposals for federal regulation of CCRs.
    As EPA weighs the eight Bevill study factors to reach our ultimate
decision, EPA will be guided by the following principles, which are
reflected in the discussions throughout this preamble. The first is
that EPA's actions must ultimately be protective of human health and
the environment. Second, any decision must be based on sound science.
Finally, in conducting this rulemaking, EPA wants to ensure that our
decision processes are transparent and encourage the greatest degree of
public participation. Consequently, to further the public's
understanding and ability to comment on all the issues facing the
Agency, within this proposal, EPA identifies a series of scientific,
economic, and materials management issues on which we are seeking
comment from the public to strengthen our knowledge of the impact of
EPA's decision.
    There are three key areas of analyses where EPA is seeking comment:
The extent of existing damage cases, the extent of the risks posed by
the mismanagement of CCRs, and the adequacy of State programs to ensure
proper management of CCRs (e.g., is groundwater monitoring required of
CCR landfills and surface impoundments). Since the 2007 NODA, EPA
received new reports from industry and environmental and citizen groups
regarding damage cases. Industry provided information indicating that
many of EPA's listed proven damage cases do not meet EPA's criteria for
a damage case to be proven. Environmental and citizen groups, on the
other hand, reported that there are additional damage cases of which
EPA is unaware. EPA's analysis, as well as the additional information
from industry and environmental and citizen groups, which is in the
docket for this proposal, needs to undergo public review, with the end
result being a better understanding of the nature and number of damage
cases. In addition, as discussed at length in sections II and IV, a
number of technical questions have been raised regarding EPA's
quantitative groundwater risk assessment. The Agency would implement
similar technical controls under RCRA subtitle C or D. Therefore, a
central issue is the adequacy of State programs. Under either
regulatory approach, State programs will have key implementation roles.
This is a very complex area to evaluate. For example, as EPA reports
that 36% of the States do not have minimum liner requirements for CCR
landfills, and 67% do not have liner requirements for CCR surface
impoundments, we also observe that nearly all new CCR landfills and
surface impoundments are constructed with liners. It should also be
recognized that while states currently have considerable expertise in
their State dam safety programs, those programs do not tend to be part
of State solid waste or clean water act programs, and so, oversight may
not be adequately captured in EPA's existing data. In several areas,
there are these types of analytical tensions that warrant careful
consideration by the public and EPA. This proposal requests states and
others to provide further information on state programs, including the
prevalence of groundwater monitoring at existing facilities (an area
where our information is nearly 15 years old) and why state programs
may address groundwater monitoring and risks differently for surface
impoundments located proximate to rivers.
    The results of the risk analysis demonstrate significant risks from
surface impoundments. A common industry practice, however, is to place
surface impoundments right next to water bodies. While the Agency's
population risk assessment analysis accounted for adjacent water
bodies, the draft risk assessment that presents individual risk
estimates does not account for the presence of adjacent water bodies in
the same manner that the population risk assessment did. EPA is
requesting public comment on the exact locations of CCR waste
management units so that the Agency can more fully account for water
bodies that may exist between a waste management unit and a drinking
water well (and thus, could potentially intercept a contaminated
groundwater plume). EPA is also requesting comments on how the risk
assessment should inform the final decision.
    While the Agency believes the analyses conducted are sound, today's
co-proposal of two options reflects our commitment to use the public
process fully to ensure the best available scientific and regulatory
impact analyses are considered in our decision. The final course of
action will fully consider these legitimate and complex issues, and
will result in the selection of a regulatory structure that best
addresses the eight study factors identified in section 8002(n) of
RCRA, and ensures protection of human health and the environment.
2. Brief Description of Today's Co-Proposals
a. Summary of Subtitle C Proposal
    In combination with its proposal to reverse the Bevill
determination for CCRs destined for disposal, EPA is proposing to list
as a special waste, to be regulated under the RCRA subtitle C
regulations, CCRs from electric utilities and independent power
producers when destined for disposal in a landfill or surface
impoundment. These CCRs would be regulated from the point of their
generation to the point of their final disposition, including during
and after closure of any disposal unit. This would include the
generator and transporter requirements and the requirements for
facilities managing CCRs, such as siting, liners (with modification),
run-on and run-off controls, groundwater monitoring, fugitive dust
controls, financial assurance, corrective action, including facility-
wide corrective action, closure of units, and post-closure care (with
certain modifications). In addition, facilities that dispose of, treat,
or, in many cases, store, CCRs also would be required to obtain permits
for the units in which such materials are disposed, treated, and
stored. The rule would also regulate the disposal of CCRs in sand and
gravel pits, quarries, and other large fill operations as a landfill.
    To address the potential for catastrophic releases from surface
impoundments, we also are proposing requirements for dam safety and
stability for impoundments that, by the effective date of the final
rule, have not closed consistent with the requirements. We are also
proposing land disposal restrictions and treatment standards for CCRs,
as well as a prohibition on the disposal of treated CCRs below the
natural water table.
b. Summary of Subtitle D Proposal
    In combination with today's proposal to leave the Bevill
determination in place, EPA is proposing to regulate CCRs disposed of
in surface impoundments or landfills under RCRA subtitle D requirements
which would establish national criteria to ensure the safe disposal of
CCRs in these units. The units would be subject to, among other things,
location standards, composite liner requirements (new landfills and
surface impoundments would require composite liners; existing surface
impoundments without liners would have to retrofit within five years,
or cease receiving CCRs and close); groundwater monitoring and
corrective action standards for releases from the unit; closure and
post-closure care

requirements; and requirements to address the stability of surface
impoundments. We are also soliciting comments on requiring financial
assurance. The rule would also regulate the disposal of CCRs in sand
and gravel pits, quarries, and other large fill operations as a
landfill. The rule would not regulate the generation, storage or
treatment of CCRs prior to disposal. Because of the scope of subtitle D
authority, the rule would not require permits, nor could EPA enforce
the requirements. Instead, states or citizens could enforce the
requirements under RCRA citizen suit authority; the states could also
enforce any state regulation under their independent state enforcement
authority.
    EPA is also considering a potential modification to the subtitle D
option, called ``D prime'' in the following table. Under this option,
existing surface impoundments would not have to close or install
composite liners but could continue to operate for their useful life.
In the ``D prime'' option, the other elements of the subtitle D option
would remain the same.
3. Summary of Estimated Regulatory Costs and Benefits
    For the purposes of comparing the estimated regulatory compliance
costs to the monetized benefits for each regulatory option, the
Regulatory Impact Analysis (RIA) computed two comparison indicators:
Net benefits (i.e., benefits minus costs), and benefit/cost ratio
(i.e., benefits divided by costs). Table 1 below provides a summary of
estimated regulatory costs and benefits for three regulatory options,
based on the 7% discount rate base case and the 50-year period-of-
analysis applied in the RIA. Furthermore, this benefit and cost summary
table displays ranges of net benefit and benefit/cost results across
three different scenarios concerning the potential impacts of each
option on the future annual beneficial use of CCRs under each option.
The first scenario presents the potential impact scenario that assumes
that the increased future annual cost of RCRA-regulated CCR disposal
will induce coal-fired electric utility plants to increase beneficial
use of CCRs. The second scenario presents a potential market stigma
effect under the subtitle C option which will induce a decrease in
future annual CCR beneficial use. The third scenario assumed that
beneficial use of CCRs continues according to its recent trend line
without any future change as a result of any of the regulatory options.
The RIA estimates both the first and second scenario incrementally in
relation to the third scenario no change trend line. Table 1 shows the
range of impacts and associated ranges of net benefits and benefit-cost
ratios across these three beneficial use scenarios for each regulatory
option. While each of these three scenario outcomes may be possible,
EPA's experience with the RCRA program indicates that industrial
generators of RCRA-regulated wastes are often able to increase
recycling and materials recovery rates after a subtitle C regulation.
Section XII in this preamble provides additional discussion of these
estimates.

    Table 1--Summary Table Comparison of Regulatory Benefits to Costs--Ranging Over All Three Beneficial Use
                                                    Scenarios
      [$Millions @ 2009$ prices and @ 7% discount rate over 50-year future period-of-analysis 2012 to 2061]
----------------------------------------------------------------------------------------------------------------
                                      Subtitle C ``Special
                                            waste''                  Subtitle D           Subtitle ``D prime''
----------------------------------------------------------------------------------------------------------------
A. Present Values:
    1. Regulatory Costs:.........  $20,349..................  $8,095..................  $3,259.
    2. Regulatory Benefits:......  $87,221 to $102,191......  $34,964 to $41,761......  $14,111 to $17,501.
    3. Net Benefits (2-1)........  ($251,166) to $81,842....  ($6,927) to $33,666.....  ($2,666) to $14,242.
    4. Benefit/Cost Ratio (2/1)..  (11.343) to 5.022........  0.144 to 5.159..........  0.182 to 5.370.
B. Average Annualized Equivalent
 Values:*
    1. Regulatory Costs..........  $1,474...................  $587....................  $236.
    2. Regulatory Benefits:......  $6,320 to $7,405.........  $2,533 to $3,026........  $1,023 to $1,268.
    3. Net Benefits (2-1)........  ($18,199) to $5,930......  ($502) to $2,439........  ($193) to $1,032.
    4. Benefit/Cost Ratio (2/1)..  (11.347) to 5.022........  0.145 to 5.159..........  0.182 to 5.370.
----------------------------------------------------------------------------------------------------------------
\*\ Note: Average annualized equivalent values calculated by multiplying 50-year present values by a 50-year 7%
  discount rate ``capital recovery factor'' of 0.07246.

B. What is the statutory authority for this action?

    These regulations are being proposed under the authority of
sections 1008(a), 2002(a), 3001, 3004, 3005, and 4004 of the Solid
Waste Disposal Act of 1970, as amended by the Resource Conservation and
Recovery Act of 1976 (RCRA), as amended by the Hazardous and Solid
Waste Amendments of 1984 (HSWA), 42 U.S.C. 6907(a), 6912(a), 6921,6924,
6925 and 6944. These statutes, combined, are commonly referred to as
``RCRA.''
    RCRA section 1008(a) authorizes EPA to publish ``suggested
guidelines for solid waste management.'' 42 U.S.C. 6907(a). Such
guidelines must provide a technical and economic description of the
level of performance that can be achieved by available solid waste
management practices that provide for protection of human health and
the environment.
    RCRA section 2002 grants EPA broad authority to prescribe, in
consultation with federal, State, and regional authorities, such
regulations as are necessary to carry out the functions under federal
solid waste disposal laws. (42 U.S.C. 6912(a)).
    RCRA section 3001(b) requires EPA to list particular wastes that
will be subject to the requirements established under subtitle C. (42
U.S.C. 6921(b)). The regulation listing such wastes must be based on
the listing criteria established pursuant to section 3001(a), and
codified at 40 CFR 261.11.
    Section 3001(b)(3)(A) of RCRA established a temporary exemption for
fly ash waste, bottom ash waste, slag waste, and flue gas emission
control waste generated primarily from the combustion of coal or other
fossil fuels, among others, and required the Agency to conduct a study
of those wastes and, after public hearings and an opportunity for
comment, determine whether these wastes should be regulated pursuant to
subtitle C requirements (42 U.S.C. 6921 (b)(3)(A)).
    Section 3004 of RCRA generally requires EPA to establish standards
applicable to the treatment, storage, and disposal of hazardous waste
to ensure that human health and the environment are protected. 42
U.S.C. 6924. Sections

3004(c) and (d) prohibit free liquids in hazardous waste landfills.
Sections 3004(g) and (m) prohibit land disposal of hazardous wastes,
unless, before disposal, those wastes meet treatment standards
established by EPA that will ``substantially diminish the toxicity of
the waste or substantially reduce the likelihood of migration of
hazardous constituents from the waste so that short-term and long-term
threats are minimized.'' (42 U.S.C. 6924(c), (d), (g), and (m)).
    RCRA section 3004(x) allows the Administrator to tailor certain
specified requirements for particular categories of wastes, including
those that are the subject of today's proposal, namely ``fly ash waste,
bottom ash waste, and flue gas emission control wastes generated
primarily from the combustion of coal or other fossil fuels'' (42
U.S.C. 6924(x)). EPA is authorized to modify the requirements of
sections 3004 (c), (d), (e), (f), (g), (o), and (u), and section
3005(j), to take into account the special characteristics of the
wastes, the practical difficulties associated with implementation of
such requirements, and site-specific characteristics, including but not
limited to the climate, geology, hydrology and soil chemistry at the
site. EPA may only make such modifications, provided the modified
requirements assure protection of human health and the environment. (42
U.S.C. 6924(x)).
    RCRA section 3005 generally requires any facility that treats,
stores, or disposes of wastes identified or listed under subtitle C, to
have a permit. 42 U.S.C. 6925(a). This section also generally imposes
requirements on facilities that become newly subject to the permitting
requirements as a result of regulatory changes, and so can continue to
operate for a period until they obtain a permit--i.e., ``interim status
facilities.'' 42 U.S.C. 6925(e), (i), (j). Congress imposed special
requirements on interim status surface impoundments in section 3005(j).
In order to continue receiving wastes, interim status surface
impoundments are generally required to retrofit the impoundment within
4 years, to install a double liner, with a leachate collection system,
and groundwater monitoring. 42 U.S.C. 6925(j)(6). In addition, wastes
disposed into interim status surface impoundments must meet the land
disposal restrictions in EPA's regulations, or the unit must be
annually dredged. 42 U.S.C. 6925(j)(11).
    RCRA Section 4004 generally requires EPA to promulgate regulations
containing criteria for determining which facilities shall be
classified as sanitary landfills (and not open dumps) so that there is
no reasonable probability of adverse effects on health or the
environment from disposal of solid wastes at such facilities.

C. Regulation of Wastes Under RCRA Subtitle C

    Solid wastes may become subject to regulation under subtitle C of
RCRA in one of two ways. A waste may be subject to regulation if it
exhibits certain hazardous properties, called ``characteristics,'' or
if EPA has specifically listed the waste as hazardous. See 42 U.S.C.
6921(a). EPA's regulations in the Code of Federal Regulations (40 CFR)
define four hazardous waste characteristic properties: Ignitability,
corrosivity, reactivity, or toxicity (See 40 CFR 261.21-261.24). All
generators must determine whether or not a waste exhibits any of these
characteristics by testing the waste, or by using knowledge of the
process that generated the waste (see Sec.  262.11(c)). While not
required to sample the waste, generators will be subject to enforcement
actions if found to be improperly managing wastes that exhibit one or
more of the characteristics.
    EPA may also conduct a more specific assessment of a waste or
category of wastes and ``list'' them if they meet the criteria set out
in 40 CFR 261.11. Under the third criterion, at 40 CFR 261.11(a)(3), a
waste will be listed if it contains hazardous constituents identified
in 40 CFR part 261, Appendix VIII, and if, after considering the
factors noted in this section of the regulations, we ``conclude that
the waste is capable of posing a substantial present or potential
hazard to human health or the environment when improperly treated,
stored, transported, or disposed of, or otherwise managed.'' We place a
chemical on the list of hazardous constituents on Appendix VIII only if
scientific studies have shown a chemical has toxic effects on humans or
other life forms. When listing a waste, we also add the hazardous
constituents that serve as the basis for listing the waste to 40 CFR
part 261, Appendix VII.
    The regulations at 40 CFR 261.31 through 261.33 contain the various
hazardous wastes that EPA has listed to date. Section 261.31 lists
wastes generated from non-specific sources, known as ``F-wastes,'' that
are usually generated by various industries or types of facilities,
such as ``wastewater treatment sludges from electroplating operations''
(see EPA Hazardous Waste No. F006). Section 261.32 lists wastes
generated from specific industry sources, known as ``K-wastes,'' such
as ``Spent potliners from primary aluminum production'' (see EPA
Hazardous Waste No. K088). Section 261.33 contains lists of commercial
chemical products and other materials, known as ``P-wastes'' or ``U-
wastes,'' that become hazardous wastes when they are discarded or
intended to be discarded.
    As discussed in greater detail later in this proposal, EPA is
considering whether to codify a listing of CCRs that are disposed of in
landfills or surface impoundments, in a new section of the regulations,
as ``Special Wastes.'' EPA is considering creating this new category of
wastes, in part, to reflect the fact that these wastes would be subject
to modified regulatory requirements using the authority provided under
section 3004(x) of RCRA (e.g., the modified CCR landfill and surface
impoundment liner and leak detection system requirements, the effective
dates for the land disposal restrictions, and the surface impoundment
retrofit requirements).
    If a waste exhibits a hazardous characteristic or is listed under
subtitle C, then it is subject to the requirements of RCRA subtitle C,
and the implementing regulations found in 40 CFR parts 260 through 268,
parts 270 to 279, and part 124. These requirements apply to persons who
generate, transport, treat, store or dispose of such waste and
establish rules governing every phase of the waste's management from
its generation to its final disposition and beyond. Facilities that
treat, store or dispose of hazardous wastes require a permit which
incorporates all of the design and operating standards established by
EPA rules, including standards for piles, landfills, and surface
impoundments. Under RCRA subtitle C requirements, land disposal of
hazardous waste is prohibited unless the waste is first treated to meet
the treatment standards (or meets the treatment standards as generated)
established by EPA that minimize threats to human health and the
environment posed by the land disposal of the waste, or unless the
waste is disposed in a unit from which there will be no migration of
hazardous constituents for as long as the waste remains hazardous. In
addition, RCRA subtitle C facilities are required to clean up any
releases of hazardous waste or constituents from solid waste management
units at the facility, as well as beyond the facility boundary, as
necessary to protect human health and the environment. RCRA subtitle C
also requires that permitted facilities demonstrate that they have
adequate financial resources (i.e., financial assurance) for
obligations, such as closure, post-closure care, necessary

clean up, and any liability from facility operations.
    The RCRA subtitle C requirements are generally implemented under
state programs that EPA has authorized to operate in lieu of the
federal program, based upon a determination that the state program is
no less stringent than the federal program. In a state that operates
under an authorized program, any revisions made to EPA requirements are
generally effective as part of the federal RCRA program in that state
only after the state adopts the revised requirement, and EPA authorizes
the state requirement. The exception applies with respect to
requirements implementing statutory provisions added to subtitle C by
the 1984 Hazardous and Solid Waste Amendments to RCRA; such
requirements are immediately effective in all states, and are enforced
by EPA.
    All RCRA hazardous wastes are also hazardous substances under the
Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA), as defined in section 101(14)(C) of the CERCLA statute. This
applies to wastes listed in Sec. Sec.  261.31 through 261.33, as well
as any wastes that exhibits a RCRA hazardous characteristic. Table
302.4 at 40 CFR 302.4 lists the CERCLA hazardous substances along with
their reportable quantities (RQs). Anyone spilling or releasing a
hazardous substance at or above its RQ must report the release to the
National Response Center, as required in CERCLA Section 103. In
addition, Section 304 of the Emergency Planning and Community Right-to-
Know Act (EPCRA) requires facilities to report the release of a CERCLA
hazardous substance at or above its RQ to State and local authorities.
Today's rule proposes an approach for estimating whether released CCRs
exceed an RQ. Wastes listed as special wastes will generally be subject
to the same requirements under RCRA subtitle C and CERCLA as are
hazardous wastes, although as discussed elsewhere in this preamble, EPA
is proposing to revise certain requirements under the authority of
section 3004(x) of RCRA to account for the large volumes and unique
characteristics of these wastes.

D. Regulation of Solid Wastes Under RCRA Subtitle D

    Solid wastes that are neither a listed and/or characteristic
hazardous waste are subject to the requirements of RCRA subtitle D.
Subtitle D of RCRA establishes a framework for Federal, State, and
local government cooperation in controlling the management of
nonhazardous solid waste. The federal role in this arrangement is to
establish the overall regulatory direction, by providing minimum
nationwide standards for protecting human health and the environment,
and to providing technical assistance to states for planning and
developing their own environmentally sound waste management practices.
The actual planning and direct implementation of solid waste programs
under RCRA subtitle D, however, remains a state and local function, and
the act authorizes States to devise programs to deal with State-
specific conditions and needs. That is, EPA has no role in the planning
and direct implementation of solid waste programs under RCRA subtitle
D.
    Under the authority of sections 1008(a)(3) and 4004(a) of subtitle
D of RCRA, EPA first promulgated the Criteria for Classification of
Solid Waste Disposal Facilities and Practices (40 CFR part 257) on
September 13, 1979. These subtitle D Criteria establish minimum
national performance standards necessary to ensure that ``no reasonable
probability of adverse effects on health or the environment'' will
result from solid waste disposal facilities or practices. Practices not
complying with the criteria constitute ``open dumping'' for purposes of
the Federal prohibition on open dumping in section 4005(a). EPA does
not have the authority to enforce the prohibition directly (except in
situations involving the disposal or handling of sludge from publicly-
owned treatment works, where Federal enforcement of POTW sludge-
handling facilities is authorized under the CWA). States and citizens
may enforce the prohibition on open dumping using the authority under
RCRA section 7002. EPA, however, may act only if the handling, storage,
treatment, transportation, or disposal of such wastes may present an
imminent and substantial endangerment to health or the environment
(RCRA 7003). In addition, the prohibition may be enforced by States and
other persons under section 7002 of RCRA.
    In contrast to subtitle C, RCRA subtitle D requirements relate only
to the disposal of the solid waste, and EPA does not have the authority
to establish requirements governing the generation, transportation,
storage, or treatment of such wastes prior to disposal. Moreover, EPA
would not have administrative enforcement authority to enforce any RCRA
subtitle D criteria for CCR facilities, authority to require states to
issue permits for them or oversee those permits, nor authority for EPA
to determine whether any state permitting program for CCR facilities is
adequate. Subtitle D of RCRA also provides less extensive authority to
establish requirements relating to the cleanup (or corrective action)
and financial assurance at solid waste facilities.
    EPA regulations affecting RCRA subtitle D facilities are found at
40 CFR parts 240 through 247, and 255 through 258. The existing part
257 criteria include general environmental performance standards
addressing eight major topics: Floodplains (Sec.  257.3-1), endangered
species (Sec.  257.3-2), surface water (Sec.  257.3-3), ground water
(Sec.  257.3-4), land application (Sec.  257.35), disease (Sec.  257.3-
6), air (Sec.  257.3-7), and safety (Sec.  257.3-8). EPA has also
established regulations for RCRA subtitle D landfills that accept
conditionally exempt small quantity generator hazardous wastes, and
household hazardous wastes (i.e., ``municipal solid waste'') at 40 CFR
Part 258, but these are of limited relevance to CCRs, which fall into
neither category of wastes.

E. Summary of the 1993 and 2000 Regulatory Determinations

    Section 3001(b)(3)(A)(i) of RCRA (known as the Bevill exclusion or
exemption) excluded certain large-volume wastes generated primarily
from the combustion of coal or other fossil fuels from being regulated
as hazardous waste under subtitle C of RCRA, pending completion of a
Report to Congress required by Section 8002(n) of RCRA and a
determination by the EPA Administrator either to promulgate regulations
under RCRA subtitle C or to determine that such regulations are
unwarranted.
    In 1988, EPA published a Report to Congress on Wastes from the
Combustion of Coal by Electric Utility Power Plants (EPA, 1988). The
report, however, did not address co-managed utility CCRs, other fossil
fuel wastes that are generated by utilities, and wastes from non-
utility boilers burning any type of fossil fuel. Further, because of
other priorities, EPA did not complete its Regulatory Determination on
fossil fuel combustion (FFC) wastes at that time.
    In 1991, a suit was filed against EPA for failure to complete a
Regulatory Determination on FFC wastes (Gearhart v. Reilly Civil No.
91-2345 (D.D.C.), and on June 30, 1992, the Agency entered into a
Consent Decree that established a schedule for EPA to complete the
Regulatory Determinations for all FFC wastes. Specifically, FFC wastes
were divided into two categories: (1) Fly ash, bottom ash, boiler slag,
and flue gas emission control waste from the combustion of coal by
electric utilities and independent commercial power

producers, and (2) all remaining wastes subject to RCRA Sections
3001(b)(3)(A)(i) and 8002(n)--that is, large volume coal combustion
wastes generated at electric utility and independent power producing
facilities that are co-managed together with certain other coal
combustion wastes; coal combustion wastes generated at non-utilities;
coal combustion wastes generated at facilities with fluidized bed
combustion technology; petroleum coke combustion wastes; wastes from
the combustion of mixtures of coal and other fuels (i.e., co-burning of
coal with other fuels where coal is at least 50% of the total fuel);
wastes from the combustion of oil; and wastes from the combustion of
natural gas.
    On August 9, 1993, EPA published its Regulatory Determination for
the first category of wastes (58 FR 42466, http://www.epa.gov/epawaste/
nonhaz/industrial/special/mineral/080993.pdf), concluding that
regulation under subtitle C of RCRA for these wastes was not warranted.
To make an appropriate determination for the second category, or
``remaining wastes,'' EPA concluded that additional study was
necessary. Under the court-ordered deadlines, the Agency was required
to complete a Report to Congress by March 31, 1999, and issue a
Regulatory Determination by October 1, 1999.
    In keeping with its court-ordered schedule, and pursuant to the
requirements of Section 3001(b)(3)(A)(i) and Section 8002(n) of RCRA,
EPA prepared a Report to Congress on the remaining FFC wastes in March
1999 (http://www.epa.gov/epaoswer/other/fossil/volume_2.pdf). The
report addresses the eight study factors required by Section 8002(n) of
RCRA for FFC wastes (see discussion in section IV. B).
    On May 22, 2000, EPA published its Regulatory Determination on
wastes from the combustion of fossil fuels for the remaining wastes (65
FR 32214, http://www.epa.gov/fedrgstr/ EPA-WASTE/2000/May/Day-22/
f11138.htm). In its Regulatory Determination, EPA concluded that the
remaining wastes were largely identical to the high-volume monofilled
wastes, which remained exempt based on the 1993 Regulatory
Determination. The high volume wastes simply dominate the waste
characteristics even when co-managed with other wastes, and thus the
May 2000 Regulatory Determination addressed not only the remaining
wastes, but effectively reopened the decision on CCRs that went to
monofills.
    EPA concluded that these wastes could pose significant risks if not
properly managed, although the risk information was limited. EPA
identified and discussed a number of documented proven damage cases, as
well as cases indicating at least a potential for damage to human
health and the environment, but did not rely on its quantitative
groundwater risk assessment, as EPA concluded that it was not
sufficiently reliable. However, EPA concluded that significant
improvements were being made in waste management practices due to
increasing state oversight, although gaps remained in the current
regulatory regime. On this basis, the Agency concluded to retain the
Bevill exemption, and stated we would issue a regulation under subtitle
D of RCRA, establishing minimum national standards. Those subtitle D
standards have not yet been issued. (Today's proposal could result in
the development of the subtitle D standards consistent with the May
2000 Regulatory Determination, or with a revision of the determination,
or the issuance of subtitle C standards under RCRA.)
    EPA also explicitly stated in the May 2000 Regulatory Determination
that the Agency would continue to review the issues, and would
reconsider its decision that subtitle C regulations were unwarranted
based on a number of factors. EPA noted that its ongoing review would
include (1) ``the extent to which [the wastes] have caused damage to
human health or the environment;'' (2) the adequacy of existing
regulation of the wastes; (3) the results of an NAS report regarding
the adverse human health effects of mercury; \4\ and (4) ``risk posed
by managing coal combustion solid wastes if levels of mercury or other
hazardous constituents change due to any future Clean Air Act air
pollution control requirements for coal burning utilities'' and that
these efforts could result in a subsequent revision to the Regulatory
Determination. For a further discussion of the basis for the Agency's
determination, see section IV below.
---------------------------------------------------------------------------

    \4\ Toxicological Effects of Methylmercury, National Academy of
Sciences, July 2000 (http://books.nap.edu/catalog.php?record_
id=9899#toc). EPA has not taken any actions regarding the May 2000
Regulatory Determination as a result of the NAS report.
---------------------------------------------------------------------------

F. What are CCRs?

    CCRs are residuals from the combustion of coal. For purposes of
this proposal, CCRs are fly ash, bottom ash, boiler slag (all composed
predominantly of silica and aluminosilicates), and flue gas
desulfurization materials (predominantly Ca-SOX compounds) that were
generated from processes intended to generate power.
    Fly ash is a product of burning finely ground coal in a boiler to
produce electricity. Fly ash is removed from the plant exhaust gases
primarily by electrostatic precipitators or baghouses and secondarily
by wet scrubber systems. Physically, fly ash is a very fine, powdery
material, composed mostly of silica. Nearly all particles are spherical
in shape.
    Bottom ash is comprised of agglomerated coal ash particles that are
too large to be carried in the flue gas. Bottom ash is formed in
pulverized coal furnaces and is collected by impinging on the furnace
walls or falling through open grates to an ash hopper at the bottom of
the furnace. Physically, bottom ash is coarse, with grain sizes
spanning from fine sand to fine gravel, typically grey to black in
color, and is quite angular with a porous surface structure.
    Boiler slag is the molten bottom ash collected at the base of slag
tap and cyclone type furnaces that is quenched with water. When the
molten slag comes in contact with the quenching water, it fractures,
crystallizes, and forms pellets. This boiler slag material is made up
of hard, black, angular particles that have a smooth, glassy
appearance.
    Flue Gas Desulfurization (FGD) material is produced through a
process used to reduce sulfur dioxide (SO2) emissions from
the exhaust gas system of a coal-fired boiler. The physical nature of
these materials varies from a wet sludge to a dry powdered material,
depending on the process. The wet sludge generated from the wet
scrubbing process using a lime-based reagent is predominantly calcium
sulfite, while the wet sludge generated from the wet scrubbing process
using a limestone-based reagent is predominantly calcium sulfate. The
dry powdered material from dry scrubbers that is captured in a baghouse
consists of a mixture of sulfites and sulfates.
    CCRs are managed in either wet or dry disposal systems. In wet
systems, materials are generally sluiced via pipe to a surface
impoundment. The material can be generated wet, such as FGD, or
generated dry and water added to facilitate transport (i.e. sluiced)
through pipes. In dry systems, CCRs are transported in its dry form to
landfills for disposal.
1. Chemical Constituents in CCRs
    The chemical characteristics of CCRs depend on the type and source
of coal, the combustion technology, and the pollution control
technology employed. For the 1999 Report to Congress and the May 2000
Regulatory Determination, EPA developed an extensive database

on the leaching potential of CCR constituents using the toxicity
characteristic leaching procedure (TCLP) from a number of sources. More
recent data on the composition of CCRs, including their leaching
potential, have been collected and are discussed in the next sub-
section. The CCR constituent database (available in the docket to this
proposal) contains data on more than 40 constituents. Table 2 presents
the median compositions of trace element TCLP leachates of each of the
main four types of large volume CCRs (fly ash, bottom ash, boiler slag,
and FGD gypsum). (Additional information, including the range of TCLP
values, is available in the docket or on-line in the documents
identified in the footnotes to the following table.)

              Table 2--TCLP Median Compositions of Coal-Fired Utility Large-Volume CCRs \5\ (mg/l)
----------------------------------------------------------------------------------------------------------------
                   Constituent                        Fly ash       Bottom ash      Boiler slag         FGD
----------------------------------------------------------------------------------------------------------------
As..............................................           0.066           0.002           0.002           0.290
Ba..............................................           0.289           0.290           0.260           0.532
B...............................................           0.933           0.163             n/a              --
Cd..............................................           0.012           0.005          0.0018           0.010
Cr\VI\..........................................           0.203           0.010           0.003           0.120
Cu..............................................             n/a             n/a           0.050             n/a
Pb..............................................           0.025           0.005          0.0025           0.120
Hg..............................................          0.0001          0.0001          0.0002          0.0001
Se..............................................           0.020          0.0013          0.0025           0.280
Ag..............................................           0.005          0.0050          0.0001           0.060
V...............................................           0.111          0.0050           0.010              --
Zn..............................................           0.285           0.015           0.075              --
----------------------------------------------------------------------------------------------------------------
n/a = data not available.
-- = too few data points to calculate statistics.
Source: Data from supporting documentation to the 1993 Regulatory Determination; values below the detection
  limit were treated as one-half the detection limit.

    The composition of FGD gypsum depends on the position within the
air emissions control system where the SO2 component is
subject to scrubbing: If scrubbing takes place up stream of the removal
of fly ash particulates, the FGD would actually comprise a mix of both
components. Table 3 presents mean TCLP trace element compositions of
FGD gypsum generated by a scrubbing operation that is located down
stream from the particulate collection elements of the air emissions
control system; it therefore represents an `end member' FGD gypsum.
---------------------------------------------------------------------------

    \5\ Compiled from Tables 3-1, 3-3, 3-5 and 3-7, in: Technical
Background Document for the Report to Congress on Remaining Wastes
from Fossil Fuel Combustion: Waste Characteristics, March 15, 1999
(http://www.epa.gov/epawaste/nonhaz/industrial/special/fossil/ffc2_
399.pdf).

Table 3--FGD Gypsum TCLP Compositions (mg/l) From: (1) Two Ohio Power Plants *\6\ (Mean Data); (2) 12 Samples of
                     Commercial Wallboard Produced From Synthetic Gypsum **\7\(Median Data)
----------------------------------------------------------------------------------------------------------------
                                                                               Bruce Mansfield  Synthetic Gypsum
                        Constituent                         Cardinal Plant *       Plant *             **
----------------------------------------------------------------------------------------------------------------
As........................................................            <0.006            0.0075           0.00235
Ba........................................................             0.373             0.270             0.043
B.........................................................             0.137            0.0255               n/a
Cd........................................................           0.00167           0.00055           0.00145
Cr........................................................           0.00587           0.00575            0.0047
Cu........................................................            <0.001            <0.001               n/a
Pb........................................................            <0.003            <0.003            0.0006
Hg........................................................          1.8x10-5          2.6x10-6           <0.0003
Se........................................................            0.0123            <0.011             0.044
V.........................................................            <0.001             0.002               n/a
Zn........................................................             0.170            0.0560               n/a
Ag........................................................               n/a               n/a          <0.00005
----------------------------------------------------------------------------------------------------------------
n/a = data not available.

    The contaminants of most environmental concern in CCRs are
antimony, arsenic, barium, beryllium, cadmium, chromium, lead, mercury,
nickel, selenium, silver and thallium. Although these metals rarely
exceed the RCRA hazardous waste toxicity characteristic (TC), because
of the mobility of metals and the large size of typical disposal units,
metals (especially arsenic) have leached at levels of concern from
unlined landfills and surface impoundments. In addition, it should also
be noted that since the Agency announced its May 2000 Regulatory
Determination, EPA has revised the maximum contaminant level (MCL) for
arsenic,\8\ without a corresponding revision of the TC. As a result,
while arsenic levels are typically well below the TC, drinking water
risks from contaminated groundwater due to releases from landfills and
impoundments may still be high. Also, as discussed below, a
considerable body of evidence has emerged indicating that the TCLP
alone is not a good predictor

of the mobility of metals in CCRs under a variety of different
conditions. This issue is further discussed in the following
subsection.
---------------------------------------------------------------------------

    \6\ Compiled from: Table 3-5, in: An Evaluation of Flue Gas
Desulfurization Gypsum for Abandoned Mine Land Reclamation, Rachael
A. Pasini, Thesis, The Ohio State University, 2009.
    \7\ Compiled from: Table 10, in: Fate of Mercury in Synthetic
Gypsum Used for Wallboard Production, J. Sanderson et al., USG
Corporation, Final Report prepared for NETL, June 2008.
    \8\ See http://www.epa.gov/safewater/arsenic/regulations.html.
---------------------------------------------------------------------------

    From Tables 2 and 3 above, it is evident that each of the main four
types of CCRs, when subjected to a TCLP leach test, yields a different
amount of trace element constituents. EPA is soliciting public comments
on whether, in light of these differences in the mobility of hazardous
metals between the four major types of CCRs, regulatory oversight
should be equally applied to each of these CCR types when destined for
disposal.
2. Recent EPA Research on Constituent Leaching From CCRs
    Changes to fly ash and other CCRs are expected to occur as a result
of increased use and application of advanced air pollution control
technologies in coal-fired power plants. These technologies include
flue gas desulfurization (FGD) systems for SO2 control,
selective catalytic reduction (SCR) systems for NOX control,
and activated carbon injection systems for mercury control. These
technologies are being installed or are expected to be installed in
response to federal regulations, state regulations, legal consent
decrees, and voluntary actions taken by industry to adopt more
stringent air pollution controls. Use of more advanced air pollution
control technology reduces air emissions of metals and other pollutants
in the flue gas of a coal-fired power plant by capturing and
transferring the pollutants to the fly ash and other air pollution
control residues. The impact of changes in air pollution control on the
characteristics of CCRs and the leaching potential of metals is the
focus of ongoing research by EPA's Office of Research and Development
(ORD). This research is being conducted to identify any potential
cross-media transfers of mercury and other metals and to meet EPA's
commitment in the Mercury Roadmap (http://www.epa.gov/hg/roadmap.htm)
to report on the fate of mercury and other metals from implementation
of multi-pollutant control at coal-fired power plants.
    Over the last few years, in cooperation with Electric Power
Research Institute (EPRI) and the utility industry, EPA obtained 73
different CCRs from 31 coal-fired boilers spanning a range of coal
types and air pollution control configurations. Samples of CCRs were
collected to evaluate differences in air pollution control, such as
addition of post-combustion NOX controls (i.e., selective
catalytic reduction), FGD scrubbers, and enhanced sorbents for mercury
capture. A series of reports have been developed to document the
results from the ORD research: The first report (Characterization of
Mercury-Enriched Coal Combustion Residuals from Electric Utilities
Using Enhanced Sorbents for Mercury Control, EPA-600/R-06/008, February
2006; http://www.epa.gov/ORD/NRMRL/pubs/600r06008/600r06008.pdf) was
developed to document changes in fly ash resulting from the addition of
sorbents for enhanced mercury capture. The second report
(Characterization of Coal Combustion Residuals from Electric Utilities
Using Wet Scrubbers for Multi-Pollutant Control; EPA-600/R-08/077, July
2008, http://www.epa.gov/nrmrl/pubs/600r08077/600r08077.pdf) was
developed to evaluate residues from the expanded use of wet scrubbers.
The third report (Characterization of Coal Combustion Residues from
Electric Utilities--Leaching and Characterization Data, EPA-600/R-09/
151, December 2009, http://www.epa.gov/nrmrl/pubs/600r09151/
600r09151.html) updates the data in the earlier reports and provides
data on an additional 40 samples to cover the range of coal types and
air pollution control configurations, including some not covered in the
two previous reports.
    Data from these studies is being used to identify potential trends
in the composition and leaching behavior of CCRs resulting from changes
in air pollution controls. Summary data on the higher volume CCRs is
provided for 34 fly ashes (Table 4) and 20 FGD gypsum samples (Table
5). The report provides analysis of other types of CCRs (i.e., non-
gypsum scrubber residues (primarily scrubber sludge containing calcium
sulfite), blended CCRs (non-gypsum scrubber residues, fly ash, and
lime), and wastewater treatment filter cake). For each of the metals
that are reported (Sb, As, Ba, B, Cd Cr, Co, Hg, Pb, Mo, Se, and Tl)
from the leaching test results, ``box and whisker'' plots have been
developed comparing the different materials and providing comparison to
field leachate data.
    The purpose of this research was to try to understand how power
plant air pollution control residues, and their leaching potential, are
likely to change with the increased use of multi-pollutant and mercury
controls, anticipated in response to new Clean Air Act regulations. An
initial focus was to identify appropriate leach testing methods to
assess leaching potential under known or expected CCR management
conditions (beneficial use or disposal). The EPA's Science Advisory
Board and the National Academy of Sciences have in the past raised
concerns over the use of single-point pH tests that do not reflect the
range of actual conditions under which wastes are plausibly managed.\9\
Because metal leaching rates change with changing environmental
conditions (especially pH), single point tests may not be the most
accurate predictor of potential environmental release of mercury or
other metals because they do not provide estimates of leaching under
some disposal or reuse conditions that can plausibly occur.
---------------------------------------------------------------------------

    \9\ National Academy of Sciences, Managing Coal Combustion
Residues in Mines; The National Academies Press, Washington, DC,
2006.
---------------------------------------------------------------------------

    In response to these concerns, a review of available leaching test
methods was conducted. A leaching test method \10\ based on research
conducted at Vanderbilt University in the United States and the Energy
Research Center of the Netherlands, among others, was selected to
address some of these concerns.
---------------------------------------------------------------------------

    \10\ Kosson, D.S.; Van Der Sloot, H.A.; Sanchez, F.;
Garrabrants, A.C., An Integrated Framework for Evaluating Leaching
in Waste Management and Utilization of Secondary Materials.
Environmental Engineering Science 2002, 19, 159-204.
---------------------------------------------------------------------------

    While EPA/ORD's research relied on the Vanderbilt method, similar
methods (i.e, tests evaluating leaching at different plausible disposal
pH values) have been used to evaluate the leaching behavior and support
hazardous waste listings of other materials as well.\11\ Because of
their general utility, the research methods have been drafted into the
appropriate format and are being evaluated for inclusion in EPA's waste
analytical methods guidance, SW-846 \12\

to facilitate their routine use for evaluating other wastes or reuse
materials (http://www.epa.gov/osw/hazard/testmethods/sw846/index.htm).
---------------------------------------------------------------------------

    \11\ See 65 FR 67100 (November 8, 2000) for a discussion of
EPA's use of multi-pH leach testing in support of listing a mercury-
bearing sludge from VCM-A production, and EPA/600/R-02/019,
September 2001, Stabilization and Testing of Mercury Containing
Wastes: Borden Catalyst.
    \12\ Five different methods have been developed for use
depending upon the information needed and the waste form.
    1. Draft Method 1313--Liquid-Solid Partitioning as a Function of
Eluate pH using a Parallel Batch Extraction Test
    2. Draft Method 1314--Liquid-Solid Partitioning as a Function of
Liquid-Solid Ratio Using an Up-flow Column Test
    3. Draft Method 1315--Mass Transfer in Monolithic or Compacted
Granular Materials Using a Semi-dynamic Tank Leach Test
    4. Draft Method 1316--Liquid-Solid Partitioning as a Function of
Liquid-Solid Ratio Using a Parallel Batch Test
    5. Draft Method 1317--Concise Test for Determining Consistency
in Leaching Behavior
    The test methods were developed to identify differences in the
constituent leaching rate resulting from the form of the tested
material, as well as the effects of pH and the liquid/solid ratio.
Fine grained materials (e.g., particle sizes of 2 mm or less) will
have greater contact with leaching solutions (in a lab test) or
rainfall (in the environment) than will solid materials such as
concrete or CCRs that are pozzolanic when exposed to water. In
applying these methods to CCRs or other materials, batch tests that
are designed to reach equilibrium are used with fine-grained or
particle-size reduced materials. For solid materials, the tests were
designed to evaluate constituent leaching from the exposed surface
(leaching of constituents that are either at the surface, or that
have migrated over time to the surface), can be used. Testing at
equilibrium provides an upper bound estimate of constituent leaching
at each set of conditions tested. In some instances, these results
may represent the real situation, since when rainfall percolation
through a material in the environment is slow, the constituent
concentration in the water passing through the materials may reach,
or nearly reach equilibrium. Testing of solid (or ``monolithic'')
materials evaluates constituent leaching from materials of low
permeability for which most rainfall flows around the material
rather than percolating through it. This results in less contact
between the rainfall and the material, and so typically, a lower
rate of constituent leaching. For monolithic materials, both the
equilibrium and monolith tests are conducted to understand the
likely initial rates of leaching from the monolith (while it remains
solid), and the upper bound on likely leaching, when the monolith
degrades over time, exposing more surface area to percolating
rainwater, and typically, higher constituent leaching rates. It may
also be possible to avoid the cost of testing solid, monolithic
materials, if the material leaches at low constituent concentrations
under the equilibrium testing conditions.
---------------------------------------------------------------------------

    For the ORD research, equilibrium batch test methods that identify
changes in leaching at different pH and liquid/solid ratio values were
used to evaluate CCRs resulting from different air pollution controls
at coal-fired power plants. This allowed evaluation of leaching
potential over a range of field conditions under which CCRs are
anticipated to be managed during either disposal or beneficial use
applications. Landfill field leachate data from EPA \13\ and EPRI \14\
studies were used to establish the range of pH conditions expected to
be found in actual disposal. From this data set, and excluding the
extreme values (below 5th percentile and above 95th percentile), a pH
range of 5.4 and 12.4 was determined to represent the range of
plausible management conditions (with regard to pH) for CCRs. This
means that approximately 5% of the values had a pH below 5.4 and
approximately 5% of the values had a pH greater than 12.4. However, it
is important to note that 9 of the 34 fly ash samples generated a pH in
deionized water (i.e., the pH generated by the tested material itself)
below pH 5.4. Therefore, these results might understate CCR leaching
potential if actual field conditions extend beyond the pH range of 5.4
and 12.4.
---------------------------------------------------------------------------

    \13\ U.S. EPA (2000) Characterization and evaluation of landfill
leachate, Draft Report. 68-W6-0068, Sept 2000.
    \14\ EPRI (2006) Characterization of Field Leachates at Coal
Combustion Product Management Sites: Arsenic, Selenium, Chromium,
and Mercury Speciation, EPRI Report Number 1012578. EPRI, Palo Alto,
CA and U.S. Department of Energy, Pittsburgh, PA.
---------------------------------------------------------------------------

    In Tables 4 and 5, the total metals content of the fly ash and FGD
gypsum samples evaluated is provided along with the leach test results.
Reference indicators (i.e., MCL,\15\ TC,\16\ and DWEL \17\) are also
provided to provide some context in understanding the leach results. It
is critical to bear in mind that the leach test results represent a
distribution of potential constituent release from the material as
disposed or used on the land. The data presented do not include any
attempt to estimate the amount of constituent that may reach an aquifer
or drinking water well. Leachate leaving a landfill is invariably
diluted in ground water to some degree when it reaches the water table,
or constituent concentrations are attenuated by sorption and other
chemical reactions in groundwater and sediment. Also, groundwater pH
may be different from the pH at the site of contaminant release, and so
the solubility and mobility of leached contaminants may change when
they reach groundwater. None of these dilution or attenuation processes
is incorporated into the leaching values presented. That is, no
dilution and attenuation factor, or DAF,\18\ has been applied to these
results. Thus, comparisons with regulatory health values, particularly
drinking water values, must be done with caution. Groundwater transport
and fate modeling would be needed to generate an assessment of the
likely risk that may result from the CCRs represented by these data.
---------------------------------------------------------------------------

    \15\ MCL is the maximum concentration limit for contaminants in
drinking water.
    \16\ TC is the toxicity characteristic and is a threshold for
hazardous waste determinations.
    \17\ DWEL is the drinking water equivalent level to be
protective for non-carcinogenic endpoints of toxicity over a
lifetime of exposure. DWEL was developed for chemicals that have a
significant carcinogenic potential and provides the risk manager
with evaluation on non-cancer endpoints, but infers that
carcinogenicity should be considered the toxic effect of greatest
concern (http://www.epa.gov/safewater/pubs/gloss2.html#D).
    \18\ For example, EPA used a generic DAF values of 100 in the
Toxicity Characteristic final regulation. (See: 55 FR 11827, March
29, 1990)
---------------------------------------------------------------------------

    In reviewing the data and keeping these caveats in mind,
conclusions to date from the research include:
    (1) Review of the fly ash and FGD gypsum data (Tables 4 and 5) show
a range of total constituent concentration values that vary over a much
broader range than do the leach data. This much greater range of
leaching values only partially illustrates what more detailed review of
the data shows: That for these CCRs, the rate of constituent release to
the environment is affected by leaching conditions (in some cases
dramatically so), and that leaching evaluation under a single set of
conditions may, to the degree that single point leach tests fail to
consider actual management conditions, lead to inaccurate conclusions
about expected leaching in the field.
    (2) Comparison of the ranges of totals values and leachate data
from the complete data set supports earlier conclusions
5119 20 21 that the rate of constituent leaching cannot be
reliably estimated based on total constituent concentration alone.
---------------------------------------------------------------------------

    \19\ Senior, C; Thorneloe, S.; Khan, B.; Goss, D. Fate of
Mercury Collected from Air Pollution Control Devices; EM, July 2009,
15-21.
    \20\ U.S. EPA, Characterization of Mercury-Enriched Coal
Combustion Residuals from Electric Utilities Using Enhanced Sorbents
for Mercury Control, EPA-600/R-06/008, Feb. 2006; http://
www.epa.gov/ORD/NRMRL/pubs/600r06008/600r06008.pdf.
    \21\ U.S. EPA, Characterization of Coal Combustion Residuals
from Electric Utilities Using Wet Scrubbers for Multi-Pollutant
Control; EPA-600/R-08/077, July 2008, http://www.epa.gov/nrmrl/pubs/
600r08077/600r08077.pdf.
---------------------------------------------------------------------------

    (3) From the more complete data in Report 3, distinctive patterns
in leaching behavior have been identified over the range of pH values
that would plausibly be encountered for CCR disposal, depending on the
type of material sampled and the element. This reinforces the above
conclusions based on the summary data.
    (4) Based on the data (summarized in Table 4), on the leach results
from evaluation of 34 fly ashes across the plausible management pH
range of 5.4 to 12.4,
    [cir] The leach results at the upper end of the leachate
concentration range exceed the TC values for As, Ba, Cr, and Se
(indicated by the shading in the table).
    (5) Based on the data (summarized in Table 5), on the leach results
from evaluation of 20 FGD gypsums across the plausible management pH
range of 5.4 to 12.4,
    [cir] The leach results at the upper end of the leachate
concentration ranges exceed the TC value for Se.
    (6) The variability in total content and the leaching of
constituents within a material type (e.g., fly ash, gypsum) is such
that, while leaching of many samples exceeds one or more of the
available health indicators, many of the other samples within the
material type may be lower than the available regulatory or health
indicators.

Additional or more refined assessment of the dataset may allow some
distinctions regarding release potential to be made among particular
sources of some CCRs, which may be particularly useful in evaluating
CCRs in reuse applications.
    EPA anticipates development of a fourth report that presents such
additional analysis of the leaching data to provide more insight into
constituent release potential for a wider range of CCR management
scenarios, including beneficial use applications. This will include
calculating potential release rates over a specified time for a range
of management scenarios, including use in engineering and commercial
applications using probabilistic assessment modeling (Sanchez and
Kosson, 2005).\22\ This report will be made publicly available when
completed.
---------------------------------------------------------------------------

    \22\ Sanchez, F., and D. S. Kosson, 2005. Probabilistic approach
for estimating the release of contaminants under field management
scenarios. Waste Management 25(5), 643-472 (2005).
---------------------------------------------------------------------------

    Finally, the Agency recognizes that this research has generated a
substantial amount of data, and believes this data set can be useful as
a reference for assessing additional CCR samples in the future. The
docket for today's rule therefore includes the full dataset, in the
form of a database to provide easier access to EPA's updated leach
data.\23\
---------------------------------------------------------------------------

    \23\ The database, called ``Leach XS Lite'' can be used to
estimate the leaching potential of CCRs under any specified set of
pH or infiltration conditions that may occur in the field. While the
database is presented as a ``Beta'' version, and may be further
developed, the data presented in the data base are final data, from
the three EPA research reports cited above.
[GRAPHIC] [TIFF OMITTED] TP21JN10.000

    Note: The dark shading is used to indicate where there could be
a potential concern for a metal when comparing the leach results to
the MCL, DWEL, or concentration level used to determine the TC. Note
that MCL and DWEL values are intended to represent concentrations at
a well and the point of exposure; leachate dilution and attenuation
processes that would occur in groundwater before leachate reaches a
well are not accounted for, and so MCL and DWEL values cannot be
---------------------------------------------------------------------------
directly compared with leachate values.

[GRAPHIC] [TIFF OMITTED] TP21JN10.001

    Note: The dark shading is used to indicate where there could be
a potential concern for a metal when comparing the leach results to
the MCL, DWEL, or concentration level used to determine the TC. Note
that MCL and DWEL values are intended to represent concentrations at
a well and the point of exposure; leachate dilution and attenuation
processes that would occur in groundwater before leachate reaches a
well are not accounted for, and so MCL and DWEL values cannot be
directly compared with leachate values.

G. Current Federal Regulations or Standards Applicable to the Placement
of CCRs in Landfills and Surface Impoundments.

    CCR disposal operations are typically regulated by state solid
waste management programs, although in some instances, surface
impoundments are regulated under the states water programs. However,
there are limited regulations of CCRs at the federal level.
    The discharge of pollutants from CCR management units to waters of
the United States are regulated under the National Pollutant Discharge
Elimination System (NPDES) at 40 CFR Part 122, authorized by the Clean
Water Act (CWA). NPDES permits generally specify an acceptable level of
a pollutant or pollutant parameter in a discharge. NPDES permits ensure
that a state's mandatory standards for clean water and the federal
minimums are being met. A number of the damage cases discussed in the
preamble also involved surface water contamination, which were
violations of the NPDES permit requirements.

II. New Information on the Placement of CCRs in Landfills and Surface
Impoundments

A. New Developments Since the May 2000 Regulatory Determination.

    Since publication of the May 2000 Regulatory Determination, new
information and data have become available, including additional damage
cases, risk modeling, updated information on current management
practices and state regulations associated with the disposal of CCRs,
petitions from environmental and citizens groups for EPA to develop
rules for the management of CCRs, an industry voluntary agreement on
how they would manage CCRs, and a proposal from environmental and
citizens groups for a CCR rule. Much of this new information was made
available to the public in August 2007 through a Notice of Data
Availability (NODA) at 72 FR 49714 (http://www.epa.gov/fedrgstr/EPA-
WASTE/2007/August/Day-29/f17138.pdf). EPA has received extensive
comments from environmental groups, industry, states and others in
response to the NODA and as we have moved toward rulemaking. All of the
comments and subsequent information we have received are included in
the docket to this proposal. The new information on risks and the
damage cases are discussed briefly below and in more detail in
subsequent sections of this proposed rule; a more detailed discussion
of this new information is discussed in other sections of the preamble.
    At the time of the May 2000 Regulatory Determination, the Agency
was aware of 14 cases of proven damages \24\ and 36 cases of potential
damages resulting from the disposal of

CCRs. The Agency has since learned of an additional 13 cases of proven
damages and 4 cases of potential damages, including a catastrophic
release of CCRs from a disposal unit at the Tennessee Valley Authority
(TVA) Kingston facility in Harriman, Tennessee in December 2008. In
total, EPA has documented 27 cases of proven damages and 40 cases of
potential damages resulting from the disposal of CCRs. Proven damage
cases have been documented in 12 states, and potential damage cases--in
17 states. See section II.C. and the Appendix to this proposal for more
detailed discussions of EPA's CCR damage cases.
---------------------------------------------------------------------------

    \24\ As discussed later in the preamble, 11 of these documented
cases of damage were to human health and the environment, while four
of these cases were cases of ecological damage, one of which has now
been reclassified as a potential damage case.
---------------------------------------------------------------------------

    As part of the process for making the May 2000 Regulatory
Determination for CCRs, EPA prepared a draft quantitative risk
assessment. However, because of time constraints, the Agency was unable
to address public comments on the draft risk assessment in time for the
Regulatory Determination. Between 2000 and 2006, EPA addressed the
public comments and updated the quantitative risk assessment for the
management of CCR in landfills and surface impoundments. The revised
risk assessment was made available for public comment in the August
2007 draft report titled ``Human and Ecological Risk Assessment of Coal
Combustion Wastes.''
    In the May 2000 Regulatory Determination, the Agency concluded that
the utility industry had made significant improvements in its waste
management practices for new landfills and surface impoundments since
the practices reflected in the 1999 Report to Congress, and that most
state regulatory programs had similarly improved. To verify its
conclusion, in 2005, the U.S. Department of Energy (DOE) and EPA
conducted a joint study to collect more recent information on the
management practices for CCRs by the electric power industry, and state
programs in 11 states. The results of the study were published in the
report titled ``Coal Combustion Waste Management at Landfills and
Surface Impoundments, 1994-2004.'' Additionally, we are aware of at
least one state (Maryland) that has recently amended its regulatory
requirements for the management of CCRs.
    In February 2004, 125 environmental and citizens groups petitioned
the EPA Administrator for a rulemaking prohibiting the disposal of coal
power plant wastes into groundwater and surface water until such time
as EPA promulgates federally enforceable regulations pursuant to RCRA.
A copy of the petition is available at http://www.regulations.gov/
fdmspublic/component/main?/main=DocumentDetail&o=09000064801cf8d1.
    In October 2006, the utility industry through their trade
association, the Utility Solid Waste Activities Group (USWAG) submitted
to EPA a ``Utility Industry Action Plan for the Management of Coal
Combustion Products.'' The plan outlines the utility industry's
commitment to adopt groundwater performance standards and monitoring,
conduct risk assessments prior to placement of CCRs in sand and gravel
pits, and to consider dry-handling prior to constructing new disposal
units.
    In January 2007, environmental and citizens groups submitted to EPA
a ``Proposal for the Federal Regulation of Coal Combustion Waste.'' The
proposal provides a framework for comprehensive regulation under
subtitle D of RCRA for waste disposed of in landfills and surface
impoundments generated by coal-fired power plants. Then in July 2009,
environmental and citizens groups filed a second petition requesting
that the EPA Administrator promulgate regulations that designate CCRs
as hazardous waste under subtitle C of RCRA.\25\ In support of their
petition, the environmental groups cited ``numerous reports and data
produced by the Agency since EPA's final Regulatory Determination * * *
which quantify the waste's toxicity, threat to human health and the
environment, inadequate state regulatory programs, and the damage
caused by mismanagement.'' A copy of the petition is available in the
docket to this proposal. The Agency has, as yet, not made a decision as
to whether to lift the Bevill exemption, and, while it has determined
that federal regulation is appropriate, it has not made a determination
as to whether regulations should be promulgated under subtitles C or D
of RCRA. Consequently, EPA is deferring its response to the petitioner.
However, the preamble discusses the issues raised in these petitions at
length. In addition, the Agency is deferring its proposed response to
the petitioners' request regarding the placement of CCRs in minefills
as the Agency will work with OSM to address the management of CCRs in
minefills in a separate rulemaking action. (See discussion in other
parts of the preamble for the Agency's basis for its decisions.)
---------------------------------------------------------------------------

    \25\ This rulemaking petition was filed by: Earthjustice; the
Sierra Club; the Environmental Integrity Project; the Natural
Resources Defense Council; the Southern Environmental Law Center;
and Kentucky Resources Council.
---------------------------------------------------------------------------

    In August 2007, EPA published a NODA (72 FR 49714, http://
www.epa.gov/fedrgstr/EPA-WASTE/2007/August/Day-29/f17138.htm) which
made public, and sought comment on, the new information we received
since the May 2000 Regulatory Determination through 2007, except for
the July 2009 petition entitled, Petition for Rulemaking Pursuant to
Section 7004(a) of the Resource Conservation and Recovery Act
Concerning the Regulation of Coal Combustion Waste and the Basis for
Reconsideration of the 2000 Regulatory Determination Concerning Wastes
from the Combustion of Fossil Fuels. The new information included the
joint DOE and EPA report entitled: Coal Combustion Waste Management at
Landfills and Surface Impoundments, 1994-2004; the draft risk
assessment; and EPA's damage case assessment. EPA also included in the
docket to the NODA the February 2004 Petition for Rulemaking submitted
by a number of environmental and citizens' groups to prohibit the
placement or disposal of CCRs into ground water and surface water; and
two suggested approaches for managing CCRs in landfills and surface
impoundments. One approach is the Voluntary Action Plan that was
formulated by the electric utility industry. The second approach was
the January 2007 framework prepared by a number of environmental and
citizens' groups proposing federal regulation under subtitle D of RCRA
for CCRs generated by U.S. coal-fired power plants and disposed of in
landfills and surface impoundments. The Agency received a total of 396
comments on the NODA from 375 citizens and citizen and environmental
groups, 16 industry groups, and 5 state and local government
organizations. In general, citizens, citizens groups, and environmental
groups commented that state regulations are inadequate and called on
EPA to develop enforceable regulations for the disposal of CCRs under
the hazardous waste provisions of RCRA. Industry groups, on the other
hand, stated that the significant recent improvement in industry
management and state regulatory oversight of CCR disposal demonstrates
that the conditions that once led EPA to determine that federal
subtitle D regulations were warranted no longer exist and therefore,
further development of subtitle D regulations is no longer necessary.
In September 2008, the Environmental Council of the States (ECOS)
issued a resolution that states already have regulations in place that
apply to CCRs, and a federal regulation is not necessary. The 2008 ECOS
resolution was revised in March 2010 and calls upon EPA to conclude
that

additional federal CCR regulations would be duplicative of most state
programs, are unnecessary, and should not be adopted, but if adopted
must be developed under RCRA subtitle D rather than RCRA subtitle C
(see http://www.ecos.org/files/4018_file_Resolution_08_14_2010_
version.doc). Comments on the NODA are available in the docket to the
NODA at http://www.regulations.gov, docket number EPA-HQ-RCRA-2006-
0796.
    Finally, in July and August of 2008, EPA conducted a peer review of
the 2007 draft risk assessment ``Human and Ecological Risk Assessment
of Coal Combustion Wastes.'' The peer review was conducted by a team of
five experts in groundwater modeling, environmental fate and transport
modeling, and human health and ecological risk assessment. EPA has
revised its risk assessment based on the peer review comments. Results
of the peer review and the revised risk assessment are included in the
docket to this proposal. Also, see section II.B. below and the document
titled ``What Are the Environmental and Health Effects Associated with
Disposing of CCRs in Landfills and Surface Impoundments?'' available
from the docket to this notice for more detailed discussions of the
risk assessment.
    In summary, since the May 2000 Regulatory Determination, the Agency
has (1) Documented an additional 17 cases of damage from the disposal
of CCRs (13 proven and 3 potential); (2) gathered additional
information on industry practices; (3) revised its risk assessment,
based on comments received on the 1999 Report to Congress, conducted a
peer review of the revised risk assessment, and further revised its
risk assessment based on peer review comments and comments received on
the August 2007 NODA; (4) received a voluntary action plan from the
utility industry; (5) received two petitions for rulemaking from
environmental and citizens groups; and (6) received a proposal for
regulating the management of CCRs in landfills and surface impoundments
from environmental and citizens groups. EPA has considered all of this
information in making the decisions on the proposals in this notice.

B. CCR Risk Assessment

    In making the May 2000 Regulatory Determination for CCRs, EPA
prepared a draft quantitative risk assessment based on groundwater
modeling. However, commenters from all sides raised fundamental
scientific questions with the study, and raised issues that went beyond
groundwater modeling capability at the time. EPA was unable to address
these issues in the available time, and therefore did not rely on the
draft risk assessment as part of its basis in making its May 2000
Regulatory Determination; rather we relied on the damage cases
identified, as well as other information. In this regard, it is worth
noting that EPA did not conclude that the available information
regarding the extent or nature of the risks were equivocal. Rather, EPA
noted that we had not definitively assessed the ground water risks, due
to the criticisms of our draft risk assessment, but still concluded
that there were ``risks from arsenic that we cannot dismiss.'' Largely
what drove the risks in the original risk assessment were the old units
that lacked liners and ground water monitoring (for landfills, only 57%
of the units had liners and 85% of the units had ground water
monitoring, while for surface impoundments, only 26% of the units had
liners and only 38% of the units had ground water monitoring).
    Between 2000 and 2006, EPA addressed public comments and updated
the quantitative risk assessment for the management of CCRs in
landfills and surface impoundments. The purpose of the risk assessment
is to identify CCR constituents, waste types, liner types, receptors,
and exposure pathways with potential risks and to provide information
that EPA can use as we continue to evaluate the risks posed by CCRs
disposed of in landfills and surface impoundments. The risk assessment
was designed to develop national human and ecological risk estimates
that are representative of onsite CCR management settings throughout
the United States. A revised draft risk assessment was made available
to the public through the August 2007 NODA (which is discussed in other
sections of the preamble) and is available at http://
www.regulations.gov/fdmspublic/component/
main?main=DocumentDetail&o=090000648027b9cc.
    EPA submitted the revised draft risk assessment report, together
with public comments on the report in response to the 2007 NODA, to a
peer review panel. EPA completed the risk assessment, taking into
account peer review comments, in a final report titled ``Human and
Ecological Risk Assessment of Coal Combustion Wastes,'' (September
2009). The report, peer review comments, and EPA's response to the peer
review comments are available in the docket for this proposal.
    For purposes of this rulemaking, EPA defined the target level of
protection for human health to be an incremental lifetime cancer risk
of no greater than one in 100,000 (10-5) for carcinogenic
chemicals and a hazard quotient of 1.0 for noncarcinogenic chemicals.
The hazard quotient is the ratio of an individual's chronic daily dose
of a constituent to the reference dose for that constituent, where the
reference dose is an estimate of the daily dose that is likely to be
without appreciable risk of deleterious effects over a lifetime. These
are the target levels that EPA typically uses in its listing decisions.
(See, for example, the final rule for Nonwastewaters From Productions
of Dyes, Pigments, and Food, Drug, and Cosmetic Colorants (70 FR 9144)
at http://www.epa.gov/wastes/laws-regs/state/revision/frs/fr206.pdf.)
    The results of this risk assessment provide further confirmation of
the high risks presented in the mismanagement of CCRs disposed in
landfills and surface impoundments. The assessment does confirm that
there are methods to manage CCRs safely, although it calls into
question the reliability of clay liners, especially in surface
impoundments, and it points to very high potential risks from unlined
surface impoundments.
    Specifically, the revised draft CCR risk assessment presents
results at a typical exposure (50th percentile), as well as a high-end
exposure (90th percentile) risk based on a probabilistic analysis. The
revised draft CCR risk assessment results at the 90th percentile
suggest that the management of CCRs in unlined or clay-lined waste
management units (WMUs) result in risks greater than the risk criteria
of 10-5 for excess cancer risk to humans or an HQ greater
than 1 for noncancer effects to both human and ecological receptors
which are the criteria generally used in EPA's listing determination
procedure.\26\ While still above the criteria, clay-lined units tended
to have lower risks than unlined units. However, it was the composite-
lined units that effectively reduced risks from all pathways and
constituents below the risk criteria. More specifically:
---------------------------------------------------------------------------

    \26\ EPA's hazardous waste listing determination policy is
described in the notice of proposed rulemaking for wastes from the
dye and pigment industries at 59 FR 66075-66077 available at http://
www.epa.gov/fedrgstr/EPA-WASTE/1994/December/Day-22/pr-98.html and
in the final rule for Nonwastewaters From Productions of Dyes,
Pigments, and Food, Drug, and Cosmetic Colorants (70 FR 9144) at
http://www.epa.gov/wastes/laws-regs/state/revision/frs/fr206.pdf.
---------------------------------------------------------------------------

    [cir] For humans exposed via the groundwater-to-drinking-water
pathway, estimated risks from clay-lined landfills that dispose of CCRs
or

CCRs co-managed with coal refuse are lower than those for unlined
landfills. However, the 90th percentile risk estimates, for arsenic
that leaks from clay-lined landfills are still above the risk
criteria--as high as 1 in 5,000 individual lifetime excess cancer
risk.\27\ When landfills are unlined, estimated risks above the
criteria occur for antimony and molybdenum, as well as arsenic (as high
as 1 in 2,000 individual lifetime excess cancer risk). In addition to
arsenic, clay-lined fluidized bed combustion (FBC) landfills also
presented estimated 90th percentile risks above the criteria for
antimony. However, unlined FBC landfills differed in that they were
estimated to exceed the risk criteria only for arsenic.\28\ At the 50th
percentile, only trivalent arsenic from CCRs codisposed with coal
refuse was estimated to exceed the risk criteria with cancer risks of 1
in 50,000.
---------------------------------------------------------------------------

    \27\ Excess cancer risk means risk in addition to pre-existing,
``background'' risk from other exposures.
    \28\ Unlined FBC landfills showed less risk as modeled; note
that the number of FBC landfills modeled was very small (seven).
---------------------------------------------------------------------------

    [cir] Arsenic and cobalt were the constituents with the highest
estimated risks for surface impoundments. Clay-lined surface
impoundments were estimated to present 90th percentile risks above the
criteria for arsenic, boron, cadmium, cobalt, molybdenum, and nitrate.
The 90th percentile clay-lined impoundment estimated risks and hazard
quotients (HQs) were as follows: for arsenic, the estimated risk was as
high as 1 in 140; cobalt's estimated HQ as high as 200, while the
estimated HQs for boron, cadmium, molybdenum and nitrate ranged from 2
to 20. The 90th percentile unlined surface impoundment estimates were
above the criteria for constituents that include arsenic, lead, cobalt
and selenium: estimated arsenic cancer risks are as high as 1 in 50,
and non-cancer effects estimates for cobalt ranged from an estimated HQ
of 0.9 to 500 depending on whether CCRs were co-managed with coal
refuse. At the 50th percentile, the only surface impoundment results
estimated to exceed the risk criteria were arsenic and cobalt: unlined
impoundments had estimated arsenic cancer risks as high as 6 in 10,000,
while clay-lined impoundments had estimated arsenic cancer risks as
high as 1 in 5,000. The 50th percentile noncancer HQs due to cobalt in
drinking water were estimated to be as high as 20 and 6 for unlined and
clay-lined surface impoundments, respectively.
    [cir] Composite liners, as modeled in this assessment, effectively
reduce risks from all constituents to below the risk criteria for both
landfills and surface impoundments at the 90th and 50th percentiles.
    [cir] The model generally predicts that groundwater risks will
occur centuries later for landfills than for surface impoundments. For
the groundwater-to-drinking water pathway for unlined landfills,
arrival times of the peak concentrations at a receptor well peaked in
the hundreds or thousands of years, while unlined surface impoundment
risks typically peaked within the first 100 years. Clay liners resulted
in later arrival of peak risks, nearly always in the thousands of years
for landfills but still in the first few hundred years for surface
impoundments. Finally, while composite liners often resulted in a
failure of the plume to reach groundwater wells, composite-lined
landfills with plumes that were estimated to reach groundwater wells
eventually had peak arsenic-in-groundwater concentrations at
approximately 10,000 years, while composite-lined surface impoundments'
plumes peaked in the thousands of years.
    [cir] For humans exposed via the groundwater-to-surface-water (fish
consumption) pathway, unlined and clay-lined surface impoundments were
estimated to pose risks above the criteria at the 90th percentile. For
CCRs managed alone in surface impoundments, these exceedances came from
selenium (estimated HQs of 3 and 2 for unlined and clay-lined units,
respectively). For CCRs co-managed with coal refuse, these exceedences
came from arsenic (3 in 100,000 and 2 in 100,000 estimated excess
cancer risks for unlined and clay-lined units, respectively). All 50th
percentile surface impoundment risks are estimated to be below the risk
criteria. No constituents pose estimated risks above the risk criteria
for landfills (including FBC landfills) at the 90th or 50th percentile.
    [cir] EPA also conducted a separate draft fugitive dust screening
assessment which indicates that, without fugitive dust controls, there
could be exceedances of the National Ambient Air Quality Standards for
fine particulate matter in the air at residences near CCR
landfills.\29\ The 1998 risk assessment \30\ also showed risks from
inhalation of chromium in fugitive dust but at levels below the
criteria.\31\
---------------------------------------------------------------------------

    \29\ EPA's decision to address fugitive dust was based on a peer
review comment to the draft Risk Assessment, stakeholder NODA
comments, photographic documentation of fugitive dust associated
with the hauling and disposal of CCRs, Agency efforts to control
fugitive dust emissions from the TVA Kingston spill (see e.g.,
http://www.epakingstontva.com/EPA%20Air%20Audits%20and%20Reviews/
Kingston%20Fly%20Ash%20-%20EPA%20Audit.pdf), and OSHA's requirement
for MSDS sheets for coal ash.
    \30\ Non-Groundwater Pathways, Human Health and Ecological Risk
Analysis for Fossil Fuel Combustion Phase 2 (FFC2): Draft Final
Report (http://www.epa.gov/osw/nonhaz/industrial/special/fossil/
ngwrsk1.pdf).
    \31\ All chromium present in the particulate matter was assumed
to be in the more toxic, hexavalent form.
---------------------------------------------------------------------------

    EPA recognizes that there are significant uncertainties in national
risk assessments of this nature, although it did attempt to address
potential uncertainties through Monte Carlo and sensitivity analyses.
Uncertainties discussed in the revised risk assessment include:
     The locations and characteristics of currently operating
facilities;
     The failure to account for direct discharges to surface
water;
     Changing conditions over the 10,000-year period modeled;