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Proposed Rule2026-07061

Hazardous and Solid Waste Management System: Disposal of Coal Combustion Residuals From Electric Utilities; Legacy/CCRMU Amendments

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Published

April 13, 2026

Issuing agencies

Environmental Protection Agency

Abstract

The Environmental Protection Agency (EPA or the Agency) is proposing several revisions to the existing federal CCR regulations, including exempting CCR dewatering structures and modifying the legacy coal combustion residual (CCR) surface impoundment and CCR management unit provisions. Additionally, EPA is proposing to establish a new compliance pathway that allows for site-specific considerations during permitting regarding the groundwater monitoring points of compliance, the cleanup levels for corrective action, the appropriate closure requirements, closure timeframes, and allowing CCR extraction for beneficial use during the post-closure care period. The Agency is also proposing to revise the definition of beneficial use by eliminating the requirement for an environmental demonstration for the non-roadway use of more than 12,400 tons of unencapsulated CCR on land, as well as proposing a definition of CCR storage pile, and proposing to exclude specific beneficial uses from federal CCR regulations. Lastly, EPA is providing notice that EPA will reopen the public comment period for the Federal CCR permit program proposed rule, published on February 20, 2020, for a period of 30 days in a future separate action.

Full Text

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<title>Federal Register, Volume 91 Issue 70 (Monday, April 13, 2026)</title>
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[Federal Register Volume 91, Number 70 (Monday, April 13, 2026)]
[Proposed Rules]
[Pages 18968-19023]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-07061]

[[Page 18967]]

Vol. 91

Monday,

No. 70

April 13, 2026

Part II

Environmental Protection Agency

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42 CFR Part 257

Hazardous and Solid Waste Management System: Disposal of Coal
Combustion Residuals From Electric Utilities; Legacy/CCRMU Amendments;
Proposed Rule

Federal Register / Vol. 91 , No. 70 / Monday, April 13, 2026 /
Proposed Rules

[[Page 18968]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 257

[EPA-HQ-OLEM-2020-0107; FRL-7814.3-01-OLEM]
RIN 2050-AH39

Hazardous and Solid Waste Management System: Disposal of Coal
Combustion Residuals From Electric Utilities; Legacy/CCRMU Amendments

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule; public hearing.

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SUMMARY: The Environmental Protection Agency (EPA or the Agency) is
proposing several revisions to the existing federal CCR regulations,
including exempting CCR dewatering structures and modifying the legacy
coal combustion residual (CCR) surface impoundment and CCR management
unit provisions. Additionally, EPA is proposing to establish a new
compliance pathway that allows for site-specific considerations during
permitting regarding the groundwater monitoring points of compliance,
the cleanup levels for corrective action, the appropriate closure
requirements, closure timeframes, and allowing CCR extraction for
beneficial use during the post-closure care period. The Agency is also
proposing to revise the definition of beneficial use by eliminating the
requirement for an environmental demonstration for the non-roadway use
of more than 12,400 tons of unencapsulated CCR on land, as well as
proposing a definition of CCR storage pile, and proposing to exclude
specific beneficial uses from federal CCR regulations. Lastly, EPA is
providing notice that EPA will reopen the public comment period for the
Federal CCR permit program proposed rule, published on February 20,
2020, for a period of 30 days in a future separate action.

DATES:
Comments due: Comments on this action must be received on or before
June 12, 2026.
Public hearing: EPA will hold an online (i.e., virtual) public
hearing on May 28, 2026. Please refer to the SUPPLEMENTARY INFORMATION
section for additional information on the public hearing.

ADDRESSES: You may send comments on this action, identified by Docket
ID No. EPA-HQ-OLEM-2020-0107, by any of the following methods:
<bullet> Federal eRulemaking Portal: <a href="https://www.regulations.gov/">https://www.regulations.gov/</a>
(our preferred method). Follow the online instructions for submitting
comments. A plain language summary of the proposed rule is also
available on the Federal eRulemaking Portal.
<bullet> Mail: U.S. Environmental Protection Agency, EPA Docket
Center, Office of Land and Emergency Management (OLEM) Docket, Mail
Code 28221T, 1200 Pennsylvania Ave. NW, Washington, DC 20460.
<bullet> Hand Delivery or Courier (by scheduled appointment only):
EPA Docket Center, WJC West Building, Room 3334, 1301 Constitution
Avenue NW, Washington, DC 20004. The Docket Center's hours of
operations are 8:30 a.m.-4:30 p.m., Monday-Friday (except Federal
Holidays).
Instructions: All submissions received must include the Docket ID
No. for this rulemaking. Comments received may be posted without change
to <a href="https://www.regulations.gov/">https://www.regulations.gov/</a>, including any personal information
provided. For detailed instructions on sending comments and additional
information on the rulemaking process, see the ``Public Participation''
heading of the SUPPLEMENTARY INFORMATION section of this document.
The public hearing will be held online (i.e., virtually). Refer to
the SUPPLEMENTARY INFORMATION section below for additional information.

FOR FURTHER INFORMATION CONTACT: Taylor Holt, Office of Resource
Conservation and Recovery, Waste Identification, Notice, and Generators
Division, Environmental Protection Agency, 1200 Pennsylvania Avenue NW,
MC: 5304T, Washington, DC 20460; telephone number: (202) 566-1439;
email address: <a href="/cdn-cgi/l/email-protection#d3bbbcbfa7fda7b2aabfbca193b6a3b2fdb4bca5">[email&#160;protected]</a>. For questions concerning the
beneficial use provisions discussed in Unit IV.C. of this preamble,
contact Tracy Atagi, Office of Resource Conservation and Recovery,
Waste Identification, Notice, and Generators Division, Environmental
Protection Agency, 1200 Pennsylvania Avenue NW, MC: 5304T, Washington,
DC 20460; telephone number: (202) 566-0511; email address:
<a href="/cdn-cgi/l/email-protection#ed8c998c8a84c3999f8c8e94ad889d8cc38a829b">[email&#160;protected]</a>. For more information on this rulemaking please
visit <a href="https://www.epa.gov/coal-combustion-residuals">https://www.epa.gov/coal-combustion-residuals</a>.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Public Participation
A. Written Comments
B. Participation in the Hybrid In-Person and Virtual Public
Hearing
II. General Information
A. Does this action apply to me?
B. What action is the agency contemplating?
C. What is the agency's authority for taking this action?
D. What are the incremental costs and benefits of this action?
III. Background
A. 2015 CCR Rule
B. 2023 Legacy Proposed Rule
C. 2024 Legacy Final Rule
D. New Information Received Since Publication of the Legacy
Final Rule
E. Beneficial Use of CCR
1. May 2000 Regulatory Determination on Fossil Fuel Combustion
Wastes
2. Beneficial Use in the 2015 CCR Rule
3. CCR Rule Litigation Related to Beneficial Use
4. Beneficial Use in the 2019 CCR Proposed Rule
5. 2020 CCR Notice of Data Availability
6. Public Comments on the Fourth Beneficial Use Criterion and
CCR Accumulations for the 2019 CCR Proposal and 2020 CCR NODA and
EPA's Decision To Repropose
IV. What is EPA proposing?
A. Amendments to the Self-Implementing Regulations
1. CCR Dewatering Structures
2. Legacy CCR Surface Impoundments
3. CCR Management Units
4. Initial Timeframes for Background Sampling for New CCR
Landfills, CCR Surface Impoundments, and Any Lateral Expansions
5. Slope Stability Requirements for Vegetation
B. New Compliance Pathway Allowing Site-Specific Considerations
During Permitting
1. Groundwater Monitoring and Corrective Action Requirements
2. Closure and Post-Closure Care Requirements
C. Beneficial Use
1. Definition of Beneficial Use
2. Revisions Related to CCR Accumulations
3. Exclusions for Specific Beneficial Uses
D. Federal CCR Permitting Rule--Reopening the Comment Period
V. The Projected Economic Impact of This Action
A. Introduction
B. Affected Universe
C. Baseline Costs
D. Costs and Benefits of the Proposed Rule
E. What analysis of children's health did we conduct?
VI. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
B. Executive Order 14192: Unleashing Prosperity Through
Deregulation
C. Paperwork Reduction Act (PRA)
D. Regulatory Flexibility Act (RFA)
E. Unfunded Mandates Reform Act (UMRA)
F. Executive Order 13132: Federalism
G. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
H. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks

[[Page 18969]]

I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution or Use
J. National Technology Transfer and Advancement Act (NTTAA)

List of Acronyms

ACAA American Coal Ash Association
AEP American Electric Power
ARAR Applicable or Relevant and Appropriate Requirement
BH Berkshire Hathaway
CAMA Coal Ash Management Act
CARA Corrective Action/Risk Assessment
CBI Confidential Business Information
CCIG Cross-Cutting Issues Group
CCR coal combustion residuals
CCRMU coal combustion residuals management unit
CERCLA Comprehensive Environmental Response, Compensation, and
Liability Act
CFR Code of Federal Regulations
CSM Conceptual Site Model
EEI Edison Electric Institute
EPA Environmental Protection Agency
F.A.C. Florida Administrative Code
FER facility evaluation report
FR Federal Register
HELP Hydrologic Evaluation of Landfill Performance
HSWA Hazardous and Solid Waste Amendments
ICR Information Collection Request
IEPA Illinois Environmental Protection Agency
LEAF Leaching Environmental Assessment Framework
MCL maximum contaminant level
MSWLF Municipal Solid Waste Landfill
NAICS North American Industry Classification System
NCDEQ North Carolina Department of Environmental Quality
N.C.G.S. General Statutes of North Carolina
NPDES National Pollution Discharge Elimination System
NRECA National Rural Electric Cooperative Association
NTTAA National Technology Transfer and Advancement Act
OMB Office of Management and Budget
PRA Paperwork Reduction Act
RCRA Resource Conservation and Recovery Act
RIA Regulatory Impact Analysis
SCDHEC South Department of Health and Environmental Control
TDEC Tennessee Department of Environment and Conservation
TVA Tennessee Valley Authority
USWAG Utility Solid Waste Activities Group
UV Ultraviolet
WIIN Water Infrastructure Improvements for the Nation

I. Public Participation

A. Written Comments

Submit your comments on this action, identified by Docket ID No.
EPA-HQ-OLEM-2020-0107, at <a href="https://www.regulations.gov">https://www.regulations.gov</a> (our preferred
method), or the other methods identified in the ADDRESSES section. Do
not submit any comments on the Federal CCR permit program proposed rule
to this docket; comments on that action must be submitted during the
reopened comment period to Docket ID No. EPA-HQ-OLEM-2019-0361 in
accordance with the future Federal Register document. Once submitted,
comments cannot be edited or removed from the docket. EPA may publish
any comment received to its public docket. Do not submit to EPA's
docket at <a href="https://www.regulations.gov">https://www.regulations.gov</a> any information you consider to
be Confidential Business Information (CBI), Proprietary Business
Information (PBI), or other information whose disclosure is restricted
by statute. Multimedia submissions (audio, video, etc.) must be
accompanied by a written comment. The written comment is considered the
official comment and should include discussion of all points you wish
to make. EPA will generally not consider comments or comment contents
located outside of the primary submission (i.e., on the web, cloud, or
other file sharing system). Please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a> for additional submission methods; the full EPA
public comment policy; information about CBI, PBI, or multimedia
submissions; and general guidance on making effective comments.

B. Participation in the Virtual Public Hearing

EPA will hold a virtual public hearing on May 28, 2026. The hearing
will convene at 9:00 a.m. Eastern time (ET) and will conclude at 6:00
p.m. (ET).
EPA will begin pre-registering speakers for the hearing upon
publication of this document in the Federal Register. To register to
speak at the hearing, please use the online registration form available
on EPA's CCR website (<a href="https://www.epa.gov/coal-combustion-residuals">https://www.epa.gov/coal-combustion-residuals</a>) or
contact the person listed in the FOR FURTHER INFORMATION CONTACT
section to register to speak at the hybrid hearing. The last day to
pre-register to speak at the hearing will be May 26, 2026. On May 26,
2026, EPA will post a general agenda for the hearing on EPA's CCR
website (<a href="https://www.epa.gov/coal-combustion-residuals">https://www.epa.gov/coal-combustion-residuals</a>).
EPA will make every effort to follow the schedule as closely as
possible on the day of the hearing; however, please plan for the
hearings to run either ahead of schedule or behind schedule.
Additionally, requests to speak will be taken the day of the hearing
according to the procedures specified on EPA's CCR website (<a href="https://www.epa.gov/coal-combustion-residuals">https://www.epa.gov/coal-combustion-residuals</a>) for this hearing. EPA will make
every effort to accommodate all speakers who register or join
virtually, although preferences on speaking times may not be able to be
fulfilled.
Each commenter will have five (5) minutes to provide oral
testimony. EPA encourages commenters to provide EPA with a copy of
their oral testimony electronically by emailing it to the person listed
in the FOR FURTHER INFORMATION CONTACT section. EPA also recommends
submitting the text of your oral comments as written comments to the
rulemaking docket. If EPA is anticipating a high attendance, the time
allotment per testimony may be shortened to no less than three (3)
minutes per person to accommodate all those wishing to provide
testimony and who have pre-registered. While EPA will make every effort
to accommodate all speakers who do not preregister, opportunities to
speak may be limited based upon the number of pre-registered speakers.
Therefore, EPA strongly encourages anyone wishing to speak to
preregister. Participation in the public hearing does not preclude any
entity or individual from submitting a written comment.
EPA may ask clarifying questions during the oral presentations but
will not respond to the presentations at that time. Written statements
and supporting information submitted during the comment period will be
considered with the same weight as oral comments and supporting
information presented at the public hearing. Verbatim transcripts of
the hearings and written statements will be included in the docket for
the rulemaking.
Please note that any updates made to any aspect of the hearing will
be posted online at EPA's CCR website at <a href="https://www.epa.gov/coal-combustion-residuals">https://www.epa.gov/coal-combustion-residuals</a>. While EPA expects the hearing to go forward as
set forth above, please monitor our website or contact the person
listed in the FOR FURTHER INFORMATION CONTACT section to determine if
there are any updates. EPA does not intend to publish a document in the
Federal Register announcing updates.
If you require the services of an interpreter, translator, or
special accommodations such as audio transcription or closed
captioning, please pre-register for the hearing with the person listed
in the FOR FURTHER INFORMATION CONTACT section and describe your needs
by May 14, 2026. EPA may not be able to arrange accommodations without
advance notice. Registrants should notify the person listed in the FOR
FURTHER INFORMATION CONTACT section and

[[Page 18970]]

indicate on the registration form any such needs when they pre-register
to speak.

II. General Information

A. Does this action apply to me?

This rule may be of interest to electric utilities and independent
power producers that fall within the North American Industry
Classification System (NAICS) code 221112. The reference to NAICS code
221112 is not intended to be exhaustive but rather provides a guide for
readers regarding entities likely to be affected by this action. This
discussion lists the types of entities that EPA is now aware could
potentially be affected by this action. Other types of entities not
described here could also be affected. To determine whether your entity
is affected by this action, you should carefully examine the
applicability criteria found in Sec. 257.50 of title 40 of the Code of
Federal Regulations (CFR). If you have questions regarding the
applicability of this action to a particular entity, consult the person
listed in the FOR FURTHER INFORMATION CONTACT section.

B. What action is the agency contemplating?

EPA is proposing to amend the regulations governing the disposal of
CCR in landfills and surface impoundments and defining the beneficial
use of CCR, codified in 40 CFR part 257, subpart D (CCR regulations).
First, the Agency is proposing to exempt CCR dewatering structures from
the CCR regulations under part 257 and to establish a new compliance
pathway that allows for site-specific considerations during permitting.
This pathway incorporates permit flexibilities for CCR units complying
with the federal CCR groundwater monitoring, corrective action, and
closure requirements under a federal or participating-state CCR permit.
Additionally, EPA is proposing to clarify the deadline by which new CCR
landfills and CCR surface impoundments (which includes any lateral
expansions) must comply with the requirement to establish background
concentrations.
EPA is also proposing to amend the regulations governing the
disposal of CCR in CCR surface impoundments that no longer receive CCR
but contained both CCR and liquids on or after October 19, 2015 and are
located at inactive facilities (i.e., legacy CCR surface impounds) and
the regulations governing the disposal of CCR in inactive and closed
landfills, in closed surface impoundments and on land where
noncontainerized accumulations of CCR are received, placed, or
otherwise managed (i.e., CCR management units or CCRMU). Specifically,
the Agency is proposing to: (1) Broaden the criteria for the closure by
removal certification for legacy CCR surface impoundments; (2) Broaden
the deferral criteria for legacy CCR surface impoundments that have
completed closure under a regulatory authority prior to November 8,
2024; and (3) Amend the scope of the CCRMU regulations.
Furthermore, EPA is proposing to revise several provisions related
to CCR beneficial use. Specifically, the Agency is proposing to revise
the definition of beneficial use by removing the fourth criterion that
requires an environmental demonstration for the non-roadway use of more
than 12,400 tons of unencapsulated CCR on land, proposing a definition
of CCR storage pile, and excluding the following beneficial uses from
federal CCR regulations: (1) CCR used in cement manufacturing at cement
kilns, (2) Flue gas desulfurization (FGD) gypsum used in agriculture,
and (3) FGD gypsum used in wallboard.
Lastly, EPA is providing notice that in a future separate action
identified by Docket ID No. EPA-HQ-OLEM-2019-0361, EPA will reopen the
public comment period for the Federal CCR permit program proposed rule
(85 FR 9940, entitled Hazardous and Solid Waste Management System:
Disposal of Coal Combustion Residuals From Electric Utilities; Federal
CCR Permit Program) for a period of 30 days. Note that comments on the
Federal CCR permit program proposed rule must be submitted to Docket ID
No. EPA-HQ-OLEM-2019-0361 during the future reopening of the comment
period to be considered.
EPA intends that the provisions of the rule be severable. In the
event that any individual provision or part of the rule is invalidated,
EPA intends that this would not render the entire rule invalid, and
that any individual provisions that can continue to operate will be
left in place.
In this proposal, EPA is not reconsidering, proposing to reopen, or
otherwise soliciting comment on any other provisions of the existing
CCR regulations beyond those specifically identified in this proposal.
For the reader's convenience, EPA has provided a background description
of existing requirements in several places throughout this preamble. In
the absence of a specific request for comment or proposed change to the
identified provisions, these descriptions do not reopen any of the
described provisions. EPA will not respond to comments submitted on any
issues other than those specifically identified in this proposal, and
such comments will not be considered part of the rulemaking record.

C. What is the agency's authority for taking this action?

EPA is publishing this rulemaking under the authority of sections
1008(a)(3), 2002(a), 4004, and 4005(a), (d) of the Solid Waste Disposal
Act of 1965, as amended by the Resource Conservation and Recovery Act
of 1976 (RCRA), as amended by the Hazardous and Solid Waste Amendments
of 1984 (HSWA) and the Water Infrastructure Improvements for the Nation
(WIIN) Act of 2016, 42 U.S.C. 6907(a), 6912(a), 6944, 6945(a) and (d).

D. What are the incremental costs and benefits of this action?

EPA establishes the requirements under RCRA sections 1008(a)(3) and
4004(a) without taking cost into account. See, Utility Solid Waste
Activities Group, et al. v. EPA (USWAG) 901 F.3d 414, 448-49 (D.C. Cir.
2018). The following cost estimates are presented in the Regulatory
Impact Analysis (RIA) and summarized in this preamble for compliance
with OMB Circular A-4 and E.O. 12866. The requirements in this rule do
not rely on these cost estimates.
The RIA estimates that the annualized cost savings of this action
will be approximately:
<bullet> $174-$194 million per year when discounting at 3%; and
<bullet> $232-$262 million per year when discounting at 7%.
The RIA estimates that the annualized change in benefits of this
action will be approximately:
<bullet> A $5 million decrease per year when discounting at 3%; and
<bullet> A $4-$2 million decrease when discounting at 7%.
Overall, the RIA estimates that the net annualized cost savings and
benefits, net of disbenefits, of this action will be $169-$189 million
per year when discounting at 3%, and $229-$260 million when discounting
at 7%.
Further information on the economic effects of this action can be
found in Unit VII. of this preamble.

III. Background

A. 2015 CCR Rule

On April 17, 2015, EPA finalized national minimum criteria for the
disposal of CCR as solid waste under

[[Page 18971]]

subtitle D of RCRA titled, ``Hazardous and Solid Waste Management
System; Disposal of Coal Combustion Residuals from Electric Utilities''
(80 FR 21302) (2015 CCR Rule). The 2015 CCR Rule, codified in subpart D
of part 257 of title 40 of the CFR, established regulations for
existing and new CCR landfills, existing and new CCR surface
impoundments, including all lateral expansions of these CCR units. The
2015 CCR Rule also imposed requirements on inactive surface
impoundments at active facilities but exempted inactive surface
impoundments at inactive facilities. The requirements consist of
location restrictions, design and operating criteria, groundwater
monitoring and corrective action requirements, closure and post-closure
care requirements, recordkeeping, notification, and website posting
requirements.
At the time of the promulgation of the 2015 CCR Rule, EPA did not
have the authority to issue CCR permits, authorize state CCR permit
programs, or otherwise provide the oversight typically performed by a
regulatory agency or permit authority. Therefore, the 2015 CCR Rule
established nationwide requirements for CCR units under a self-
implementing regulatory structure. Due to the lack of regulatory
oversight and the limitations of a national risk assessment, as
described in Unit III.D. below, the 2015 CCR Rule did not allow for
site-specific variances from the regulations or tailored requirements
based on site-specific characteristics. Instead, the 2015 CCR Rule
relied on certifications by qualified professional engineers and web
posting requirements as a substitute for regulatory oversight in
certain cases.
As discussed in Unit IV.B. of this preamble, the self-implementing
framework and national requirements have resulted in a one-size-fits-
all approach to compliance with the federal CCR requirements. For
example, site-specific revisions to the technical standards are not
permissible under the 2015 CCR Rule due to the lack of regulatory
oversight. Likewise, as discussed in Unit III.B.1.b. of this preamble,
during the development of the 2015 Rule, EPA rejected requests to allow
regulated entities to establish alternative groundwater standards for
constituents without a federal maximum contaminant level (MCL)
established under Sec. Sec. 141.62 and 141.66 and referenced in Sec.
257.95(h)(1) due to a lack of regulatory oversight and scientific
expertise. Consequently, the 2015 CCR Rule represents a regulatory
structure that met the RCRA standard of no reasonable probability of
adverse effect to health or the environment within the constraints of
the law at that time. However, as discussed in further detail in Units
III.D. and IV.B. of this preamble, the self-implementing framework is
no longer the only, nor the best, regulatory structure available.

B. 2023 Legacy Proposed Rule

On May 18, 2023, EPA proposed revisions to the CCR regulations (88
FR 31982) (``the Legacy Proposed Rule'' or ``Legacy Proposal''). These
revisions included establishing regulations specifying that legacy CCR
surface impoundments are subject to 40 CFR part 257, subpart D and that
owners or operators of legacy CCR surface impoundments must comply with
all the appropriate requirements applicable to inactive CCR surface
impoundments at active facilities. In addition, EPA proposed to
establish requirements to address the risks from certain exempt solid
waste management that involves the direct placement of CCR on the land
(i.e., CCRMU). EPA proposed to extend a subset of the existing
requirements in part 257, subpart D to CCRMU, which was proposed to
include CCR surface impoundments and landfills that closed prior to the
effective date of the 2015 CCR Rule, inactive CCR landfills, and other
areas where CCR is managed directly on the land. EPA proposed to apply
the CCRMU provisions to all active CCR facilities and all inactive
facilities with a legacy CCR surface impoundment.

C. 2024 Legacy Final Rule

On May 8, 2024, EPA established regulations applicable to inactive
surface impoundments at inactive facilities (legacy CCR surface
impoundments or legacy impoundments) under 40 CFR part 257, subpart D
(89 FR 38950) (Legacy Final Rule). EPA also established regulations
requiring owners and operators of legacy CCR surface impoundments to
comply with the following requirements in the existing CCR regulations:
installation of a permanent marker, history of construction, hazard
potential classification, structural stability and factors of safety
assessments, emergency action plan, air criteria, inspections,
groundwater monitoring and corrective action, closure and post-closure
care, recordkeeping, and notification and CCR website requirements. EPA
further established new compliance deadlines for these newly applicable
regulatory requirements to ensure the owners or operators of these
units have time to come into compliance.
In addition, the Legacy Final Rule established requirements to
address the risks from solid waste management activities that involves
the direct placement of CCR on the land. EPA extended a subset of the
existing requirements in 40 CFR part 257, subpart D to CCRMU, which are
CCR surface impoundments and landfills that closed prior to the
effective date of the 2015 CCR Rule, inactive CCR landfills, and other
areas where CCR is managed directly on the land. These additional
requirements apply to all active CCR facilities, all inactive
facilities with legacy CCR surface impoundments, and those active
facilities (i.e., facilities producing electricity for the grid as of
October 19, 2015) that ceased placing CCR in onsite CCR units prior to
the effective date of the 2015 CCR Rule.
Owners or operators of some legacy CCR surface impoundments and
CCRMU that had closed under a regulatory authority are eligible for
certain relief from the established regulatory requirements provided
they met specific criteria. Owners or operator of legacy CCR surface
impoundments who certify that prior to November 8, 2024, they completed
closure by removal of the impoundment, consistent with the standards in
Sec. 257.102(c), are subject to no further requirements under the
Legacy Final Rule for that unit. Similarly, for legacy CCR surface
impoundments and CCRMU that completed a closure prior to November 8,
2024, and can meet the criteria in Sec. 257.101(g), compliance with
the closure criteria in Sec. 257.102 is deferred until a permitting
authority can evaluate the previous closure to determine if it met the
appropriate section of the Sec. 257.102 closure standard. Owners or
operators of these units are still required to comply with rest of the
applicable CCR regulations.
Owners or operators of an active facility or a facility with a
legacy CCR surface impoundment are required to conduct a facility
evaluation to identify and delineate any CCRMU at the facility and
document the findings in two reports, FER Part 1 and FER Part 2. See
Sec. 257.75(b). The FER Part 1 documents the thorough review of
readily and reasonably available records regarding where CCR was either
routinely and systematically placed on land, or where facility
activities otherwise resulted in measurable accumulations of CCR on
land. The FER Part 2 documents the conclusions of a physical evaluation
of the facility to address any data and information gaps identified in
FER Part 1. Together, the FER Parts 1 and 2 give a complete picture of
the historic use, placement and the status of CCR at the facility,
ultimately identifying any

[[Page 18972]]

CCRMU of 1 ton or greater onsite. After identifying the regulated CCRMU
through the facility evaluation, owners or operators of CCRMU must
comply with the existing requirements in 40 CFR part 257, subpart D for
groundwater monitoring, corrective action (where necessary), and in
certain cases, closure, and post-closure care requirements.

D. New Information Received Since Publication of the Legacy Final Rule

Since publication of the Legacy Final Rule, EPA received
information from numerous companies and representatives of industry
regarding the scope of the deferrals within the Legacy Final Rule, the
scope of the CCRMU universe, challenges complying with the existing CCR
requirements, and requests for regulatory changes.\1\ Several of these
letters and materials critiqued the findings or applicability of the
2014 and 2024 Risk Assessments conducted by EPA to support the 2015 CCR
Rule and the Legacy Final Rule, respectively. Most recently, EPA
received two reports that critique the Agency's Risk Assessments, which
were prepared on behalf of various industry groups.2 3
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\1\ These materials are available in the docket for this
rulemaking.
\2\ Haley Aldrich. 2025. ``Report on Joint Data Analysis to
Support Revisions to Federal Regulation of Coal Combustion
Residuals.'' Prepared for American Electric Power, Duke Energy
Corporation, Southern Company Services Inc., and Vistra Corp.,
Greenville, SC. September.
\3\ Gradient. 2025. ``Technical Evaluation of the Environmental
Protection Agency's 2024 Risk Assessment of CCR Management Units.''
Prepared for Utility Solid Waste Activities Group and National Rural
Electric Cooperative Association. Boston, MA. November.
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Throughout the rulemaking process and thereafter, EPA has received
comments from industry groups and individual companies criticizing both
the 2014 and 2024 Risk Assessments as overly conservative. These
comments frequently reference some combination of literature and field
data to assert the risks posed by individual units are not as high as
those reported in the two risk assessments. The Agency has previously
addressed various iterations of these types of comments in the preamble
discussions and response to comments documents for both the 2015 CCR
Rule and the Legacy Final Rule, and so does not replicate those
specific responses here. Instead, the following discussion focuses on
the broader theme of these comments, which is that not every CCR unit
will pose the same level of risk.
The ``Report on Joint Data Analysis'' states that it draws on site-
specific data from 38 CCR landfills, surface impoundments and CCR
management unit fills at 19 stations across nine states. This report
summarizes unit characteristics and groundwater monitoring data, along
with data drawn from broader literature, and compared those data
against values modeled in the Risk Assessments. The other report,
``Technical Evaluation,'' summarizes a separate effort to re-evaluate
the modeling approach for CCRMU fills. This effort involved varying
different model inputs used in the screening phase of the 2024 Risk
Assessment and evaluating how that altered those initial risk results.
Both reports conclude that EPA's Risk Assessments systematically
overstate the risk from CCR disposal units and fills, and that it would
be more effective and appropriate to assess risks on a site-specific
basis. For example, the ``Technical Evaluation'' emphasized that
individual fills are generally smaller than the disposal units
regulated in 2015. The 2024 Risk Assessment demonstrated that risks
tend to decrease along with size due to the smaller volumes of leachate
generated. The fills associated with high-end risks that formed the
basis for national regulation tend to be on the larger end of the size
spectrum. However, there remains a sizeable fraction of modeled
scenarios where smaller units were found to result in no adverse
impacts to groundwater quality. EPA has acknowledged there is a lack of
data from facilities about the actual distribution of fill sizes across
the country. As such, there is potential that the prevalence of these
smaller fills were underrepresented in previous modeling.
The 2014 and 2024 Risk Assessments aimed to incorporate the best
available data at the time of each assessment. Site-specific data were
used where available, supplemented by regional and national data to
fill data gaps, to capture the variability of waste management
practices, environmental conditions, and receptor behavior. However, it
is inevitable that some sources of uncertainty and variability will
remain in any risk assessment. To account for this fact, EPA typically
considers a ``high-end'' exposure level to ensure an adequate margin of
safety for most of the potentially exposed, susceptible population, or
ecosystem. EPA's high-end levels typically fall around the 90th
percentile and above, an approach designed to be consistent with both
legislative mandates and recommendations from the National Academy of
Sciences' National Research Council.\4\
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\4\ U.S. EPA. 2004. ``An Examination of EPA Risk Assessment
Principles and Practices.'' EPA/100/B-04/00. Prepared by the Office
of the Science Advisor. Washington, DC. March.
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EPA uses a national risk assessment for a particular source or
industry category to inform its decision concerning whether a
regulatory program is needed or in need of revisions. Both the 2014 and
2024 Risk Assessments were designed to capture the full spectrum of
potential disposal scenarios across the country with available data.
Decisions about the need for national regulations were based on high-
end risks identified from across these scenarios, considered together
with damage cases, to ensure that regulations would be consistently
protective. Consequently, the 2014 Risk Assessment has served its
purpose as EPA used it to inform its decision to create the 2015 CCR
Rule creating a Federal CCR regulatory program. EPA relied on the 2024
Risk Assessment to inform its decision to expand the Federal CCR
regulations to cover CCRMU.
The Agency acknowledges that these high-end risks may not manifest
at every site and concurs that risks associated with individual CCR
units may be lower. This is equally true for disposal units, fills,
piles, and unencapsulated accumulations on the land for any other
stated purpose. However, pinpointing conditions that would lead to
reliably lower risks and justify less stringent national standards is
complicated by limited site characterization and various factors that
could not be reliably modeled at a national level, such as waste
disposed below the water table. While this diversity of site conditions
creates uncertainty in a national model, it provides a key rationale
for the need to design a regulatory program that can account for these
site-specific conditions while providing for sufficient regulatory
oversight.
Owners or operators of regulated facilities have installed
groundwater monitoring networks downgradient of regulated disposal
units. Whether prior to or since promulgation of the 2015 CCR Rule,
these systems are designed to demonstrate whether a release has
occurred. If a release is detected, additional information about the
magnitude and extent of the release from the unit and the potential for
contamination to spread is required to design a remedial system. That
type of broader site characterization typically occurs as part of
remedy selection, which most sites have either not yet triggered or
completed. Consequently, while industry comments providing further
information may lack the types or resolution of data needed to

[[Page 18973]]

meaningfully update the existing national risk assessments, the
submitted data and description of regulatory oversight provide a
foundation for revisions to the self-implementing 2015 CCR Rule to add
an option for site-specific determinations involving a permitting
authority. A number of commenters cited to data drawn from the broader
literature, rather than site-specific measurements. While national data
is helpful, any further refinement of the existing risk record will
likely need to rely on data from individual sites, where more
representative data can be reliably compiled.
To address identified risks in the 2014 Risk Assessment, EPA
promulgated national requirements under the authorities in sections
1008(a), 4004, and 4005(a) of RCRA. This included detailed,
prescriptive requirements for design of groundwater monitoring systems
and corrective action programs drawn from the existing 40 CFR parts 264
and 258 regulations. Decades of experience implementing these
requirements for a variety of other wastes, under a range of
conditions, provided the Agency confidence that similar performance
standards would be equally protective for CCR disposal. When EPA later
expanded the regulated universe as part of the Legacy Final Rule to
include legacy surface impoundments and CCRMU, the Agency promulgated
requirements intended to provide comparable standards across the
regulated universe.
During these rulemakings, EPA received numerous comments requesting
that EPA adopt alternative performance standards that would allow a
permit authority, such as a state regulator (or owners or operators of
facilities) to ``tailor'' the requirements to particular site
conditions. Many requested EPA adopt particular performance standards
found in EPA's municipal solid waste landfill (MSWLF) regulations in 40
CFR part 258.
Although the 2015 CCR Rule was largely modeled on the MSWLF
regulations, as explained in both the proposed and final rules, at the
time EPA lacked the authority to establish a program analogous to part
258, which relies on approved states to implement the federal criteria
through a permitting program. In addition, in 2015, EPA could not issue
permits or enforce any of the CCR regulations. In the absence of a
mandated oversight mechanism to ensure that the alternative standards
would be technically appropriate, EPA concluded it could not adopt many
of the ``more flexible'' performance standards that commenters
requested. Many of these provisions are not tied to specific
performance standards that could be used to readily judge compliance.
EPA concluded that allowing individual owners and operators to
interpret and implement these provisions in the absence of any mandated
oversight mechanism would create too much potential for
misinterpretation. Instead, the 2015 CCR Rule was designed to be self-
implementing, tied to concrete performance and design standards that
must be met, so that the rule could be implemented and compliance
demonstrated without any interaction with state or federal regulatory
officials.
However, in 2016, the WIIN Act was enacted, establishing new
statutory provisions applicable to CCR units, including: (a)
Authorizing States to implement the CCR regulations through an EPA-
approved permit program; and (b) Authorizing EPA to enforce the
regulations and, in certain situations, to serve as the permit
authority. In doing so, this legislation provides an opportunity to
move away from the ``one-size-fits-all'' regulatory approach
necessitated by the previous statutory structure.
EPA therefore proposes to create an additional regulatory pathway
that incorporates new regulatory provisions providing permit
authorities the ability to approve certain flexibilities for owners or
operators complying with the federal CCR rules under a federal or
participating-state CCR permit. The aim of these revisions is to allow
a permit authority to establish permit conditions that are better
tailored to site conditions. Typically permit authorities can require
collection of any additional site data necessary to establish permit
conditions, and consequently can develop a better understanding of
individual sites than could be achieved in national risk assessments. A
refined risk record developed through the permitting process would
supersede the previous national assessments. As discussed above, the
2015 CCR Rule was based on high-end risks from across the country,
which incorporated regional or national data where site-specific data
was unavailable. Consequently, it is expected that a permit authority
may determine a set of technical requirements different than those set
forth in the national, self-implementing scheme that will achieve the
standard of ``no reasonable probability of adverse effects on health or
the environment'' and better account for the site-specific data and
risks of individual units and sites. Most provisions discussed
throughout this proposal will allow these permit authorities to provide
greater flexibility to owners or operators while ensuring there is no
reasonable probability of adverse effects on health or the environment
from the regulated units.
This is especially relevant to D.C. Circuit caselaw preserving
EPA's discretion, when supported by evidence in the record, to classify
disposal facilities, set standards for disposal, and structure closure
proceedings. In Utility Solid Waste Activities Group v. EPA, 901 F.3d
414, 425 (D.C. Cir. 2018) (``USWAG''), the U.S. Court of Appeals for
the D.C. Circuit vacated several provisions of the 2015 CCR rule that
authorized the continued operation of unlined and clay-lined
impoundments and that exempted legacy CCR surface impoundments, finding
portions of the 2015 CCR rule to be promulgated without an adequate
record to demonstrate regulatory compliance with RCRA. In particular,
the court found it ``inadequate under RCRA for the EPA to conclude that
a major category of impoundments [(i.e., unlined surface impoundments)]
that the agency's own data show are prone to leak pose `no reasonable
probability of adverse effects on health or the environment . . .
simply because they do not already leak.'' Id. at 427. In addition, the
court determined that EPA failed to ``explain how the [2015 CCR] Rule's
contemplated detection and response could assure `no reasonable
probability of adverse effects to health and the environment' at
unlined [surface] impoundments,'' as well as at ``existing impoundments
lined with nothing more than compacted soil [i.e., clay-lined surface
impoundments].'' Id. at 431. Similarly, the court found that EPA lacked
sufficient rationale to support exempting legacy CCR surface
impoundments from the 2015 CCR Rule. See id. at 432. Overall, the
court's focus on the Agency's lack of rationale to support the vacated
portions of 2015 CCR Rule does not preclude future changes to EPA's
Part 257 regulations.
Of particular note, while not relevant to the court's determination
that portions of the 2015 CCR Rule were arbitrary and capricious, the
court recognized that the WIIN Act provides EPA with ``new tools[,]''
Id. at 437, to address CCR. Most notably, the Administrator may approve
qualified state permit programs or other systems of prior approval and
conditions under State law--for regulation by the State of CCR units--
to operate in lieu of EPA regulation of CCR units in the State. See 42
U.S.C. 6945(d)(1)(B) (d)(3). This broad discretion for the
Administrator to approve state permit programs contemplates various
standards for what triggers closure, what constitutes

[[Page 18974]]

adequate protection of the environment, and the sequencing and
timeliness of closure procedures based upon a holistic review of
environmental concerns.
As stated elsewhere, the WIIN Act, 42 U.S.C. 6945(d), enhances such
flexibility as long as any state permit program or other system of
prior State approval is in full compliance with the EPA's Part 257, or
successor regulations establishing criteria, governing CCR units. 42
U.S.C. 6945(d)(6). This flexibility is unchallenged by the USWAG
decision as long as, as stated by the court, EPA's regulatory standard
for disposal of solid waste ``ensure[s] that there is no reasonable
probability of adverse effects on health or the environment.'' See
USWAG, 901 F.3d at 448-49 (``RCRA's statutory language instructs the
EPA to classify a disposal site as a sanitary landfill and not an open
dump only `if there is no reasonable probability of adverse effects on
health or the environment from disposal of solid waste at such
facility.' (emphasis omitted)); see also Id. at 437 (``[A]lthough the
WIIN Act does not affect the validity of the Rule itself, it does
provide the EPA with new tools to pursue its regulatory goals'').
Thus, USWAG is best understood as rejecting the record at issue in
that case as insufficient to defend the standards promulgated. This
leaves intact a permitting regime which, buttressed by an adequate
demonstration that the ``no reasonable probability'' standard would be
met, could still account for site-specific variability. The record
established here and through comments to this proposal may support
defining an acceptable level of leakage on a unit- or site-specific
basis. Such case-by-case analysis may enable each regulatory authority
to opt not to close facilities immediately upon monitoring revealing
risks but rather enable owners or operators to flexibly comply with an
ongoing monitoring regime which guarantees safety. This discretion is
cabined by statute and by the court in USWAG in that the Administrator
may only approve a state alternative permit program if its standards
are at least as protective as the criteria set by the EPA in its
corresponding (and successor) regulations. See 42 U.S.C. 6945(d)(1)(C);
40 CFR part 257, subpart D.
In USWAG the Court found that EPA had not adequately demonstrated
that certain parts of the 2015 regulations adequately met the statutory
protectiveness standard in RCRA 4004(a). However, that decision was
based on the record EPA used to support its 2015 CCR rule, which was
before the court at the time, and USWAG does not foreclose further
evaluation and consideration of risk in regulating in this area. See,
e.g., USWAG, 901 F.3d at 429 (``EPA has not shown that harmful leaks
will be promptly detected; that, once detected, they will be promptly
stopped; or that contamination, once it occurs, can be remedied.'')
Left intact is the interpretation of section 4004(a) as requiring a
baseline standard of protection, but not uniformity in the manner of
attainment, and EPA maintains broad discretion to adopt performance-
based criteria based on a record of protectiveness in various state
instances. The USWAG court merely found that the record then at issue
did not explain how the specific groundwater monitoring and corrective
actions proposed were sufficient to mitigate the risks proscribed by
statute.
In keeping with USWAG's admonition of the insufficient evidence and
analysis behind the 2015 CCR Rule, EPA is seeking additional comment
and record support regarding the use of evidence-based engineering
controls, institutional controls, risk assessments, hydrogeological
assessments and monitoring techniques.
Additionally, EPA solicits comment and data regarding alternative
closure timelines which holistically consider the harms posed to the
environment by standards of closure which may fail to account for site-
specific factors. The USWAG decision does not foreclose the Agency from
designing an alternative regulatory path that defines the circumstances
that would ``trigger'' a case-by-case, site-specific analysis or one
that sets a new identifiable standard to guide the Agency or a
permitting authority's judgment when operating under that path.
RCRA requires EPA to set minimum criteria for sanitary landfills
that prevent harm to either ``health or the environment.'' 42 U.S.C.
6944(a). Thus, commenters should focus on the circumstances that should
``trigger'' a case-by-case analysis and identify the case-specific
scenarios necessitating unique regulatory treatment. EPA's discretion
to incorporate such judgments into the general standard of ``no
reasonable probability of adverse effects'' remains intact. And even
post closure trigger, EPA retains discretion to determine the timing
and sequencing of closure activities based on the record support. This
proposal seeks to further facts that point to specific site-based
variations which validate and call for the flexible approach to
regulatory approval contemplated by the WIIN Act and section 257
authority, as well the interplay between the ``new tools'' created by
the WIIN Act and the changes to the ``default federal regulatory
regime,'' Waterkeeper Alliance, Inc. v. Regan, 41 F.4th 654, 662 (D.C.
Cir. 2022) that would be sufficient to meet RCRA's ``no reasonable
probability of adverse effects to human health or the environment''
standard.

E. Beneficial Use of CCR

1. May 2000 Regulatory Determination on Fossil Fuel Combustion Wastes
In 2000, EPA published a final regulatory determination that
addressed the management of fossil fuel combustion wastes under RCRA.
In this regulatory determination, the Agency concluded that regulation
as hazardous waste was not warranted for these wastes, which included
coal combustion residuals. (65 FR 32214, May 22, 2000).
The 2000 determination also specifically addressed beneficial uses
of CCR, acknowledging the significant environmental and economic
benefits these uses can provide. Beneficial uses include a range of
applications that effectively conserve natural resources and reduce
disposal costs. These included construction applications such as
cement, concrete, and wallboard, where the materials were encapsulated,
thus minimizing exposure risks. The determination also assessed
agricultural uses as lime substitutes, revealing lower risk levels than
previously anticipated, thereby supporting continued exemption. In the
2000 regulatory determination, EPA states that ``. . . we have decided
that national regulation under subtitle C or subtitle D is not
warranted for any of the other beneficial uses of coal combustion
wastes.'' (65 FR 32221, May 22, 2000)
2. Beneficial Use in the 2015 CCR Rule
On April 17, 2015, EPA finalized the 2015 CCR Rule to regulate the
disposal of CCR as solid waste under subtitle D of RCRA (80 FR 21302,
April 17, 2015). The 2015 CCR rule established national minimum
criteria for classification of solid waste disposal facilities and
practices, codified at 40 CFR part 257, subpart D.
In the 2015 CCR final rule, EPA retained the original 2000
Regulatory Determination for CCR that is beneficially used. (80 FR
21329). EPA also established in the final rule a beneficial use
definition to distinguish between beneficial use of CCR, which is not
subject to federal regulation, and the disposal of CCR, which is
subject to regulation under 40 CFR part 257, subpart D (See 80 FR
21347).

[[Page 18975]]

The beneficial use definition is comprised of four criteria: (1)
The CCR must provide a functional benefit; (2) The CCR must substitute
for the use of a virgin material, conserving natural resources that
would otherwise need to be obtained through practices such as
extraction; (3) The use of the CCR must meet relevant product
specifications, regulatory standards, or design standards, when
available, and where such specifications or standards have not been
established, CCR may not be used in excess quantities; and (4) When
unencapsulated use of CCR involves placement on the land of 12,400 tons
or more in non-roadway applications, the user must demonstrate and keep
records, and provide such documentation upon request, that
environmental releases to groundwater, surface water, soil, and air are
comparable to or lower than those from analogous products made without
CCR, or that environmental releases to groundwater, surface water,
soil, and air will be at or below relevant regulatory and health-based
benchmarks for human and ecological receptors during use. See: 40 CFR
257.53 and 80 FR 21349-54 (April 15, 2015). In addition, EPA stated in
the preamble that ``the Agency expects potential users of
unencapsulated CCR below this [12,400 ton] threshold to work with the
states to determine the potential risks of the proposed use at the site
and to adopt the appropriate controls necessary to address the risks.''
(80 FR 21353)
3. CCR Rule Litigation Related to Beneficial Use
The 2015 CCR rule was challenged by several different parties,
including a coalition of regulated entities and a coalition of
environmental organizations. See USWAG et al v. EPA, No. 15-1219 (D.C.
Cir.).
On September 13, 2017, EPA granted petitions from the Utility Solid
Waste Activities Group (USWAG) and AES Puerto Rico LLP, requesting the
Agency initiate rulemaking to reconsider certain provisions of the 2015
final rule. In light of that decision, EPA requested that the D.C.
Circuit Court of Appeals hold the case in abeyance until the Agency had
completed its reconsideration. EPA subsequently requested that the
court remand certain provisions of the 2015 CCR rule on the grounds
that the Agency was reconsidering the provisions.
Included in that remand request were two sets of provisions related
to the beneficial use of CCR: (1) The 12,400-ton threshold in the
beneficial use definition, and (2) The requirements for ``piles'' of
CCR located onsite of a utility and those that are located off-site but
destined for beneficial use. On August 21, 2018, the D.C. Circuit Court
of Appeals granted EPA's request to remand the challenged beneficial
use provisions back to EPA in order to allow the Agency to complete its
administrative reconsideration.
4. Beneficial Use in the 2019 CCR Proposed Rule
On August 14, 2019, EPA published a proposed rule titled
``Hazardous and Solid Waste Management System: Disposal of Coal
Combustion Residuals from Electric Utilities; Enhancing Public Access
to Information; Reconsideration of Beneficial Use Criteria and Piles''
(84 FR 40353, August 14, 2019) (2019 CCR proposal). In the 2019 CCR
proposed rule, EPA proposed to redefine the criteria for beneficial use
of CCR, shifting from a 12,400-ton mass-based numerical threshold to
specific location-based criteria as the threshold for requiring an
environmental demonstration. This location-based approach aligned with
practices observed in state beneficial use programs, which often
incorporate location-based restrictions to safeguard sensitive areas
(84 FR 40358-60). The rationale for this proposed change stemmed from
the need to accurately identify when the use of unencapsulated CCR on
the land should require further demonstration that the use does not
present a reasonable probability of adverse effects on health or the
environment. The previous mass-based threshold, which required a
demonstration for uses exceeding 12,400 tons, was based on a unit
conversion error made when evaluating data regarding landfill sizes.
EPA proposed location-based criteria to reflect siting and construction
considerations that more directly impacted environmental risks from
CCR. These criteria included factors such as proximity to groundwater,
wetlands, flood plains, and seismic zones, which were known to
influence the potential for environmental releases. The Agency also
requested comment on how these criteria would impact state beneficial
use programs.
The 2019 CCR proposal also requested comments on whether a mass-
based threshold should be retained, and if so, what the appropriate
value should be. The proposal also requested comment on the possibility
of using both mass-based and location-based criteria to trigger
environmental demonstrations for unencapsulated CCR uses, or whether
every unencapsulated use of CCR should be subject to an environmental
demonstration, regardless of size or location.
Finally, the proposal requested comment on whether the beneficial
use definition should include a requirement for notifying relevant
parties when CCR was placed on land. This requirement could involve
informing state agencies, landowners, or the public, similar to
practices in some state programs.
The 2019 CCR proposal also included proposed revisions to the
requirements applicable to piles of CCR. Under existing regulations,
CCR piles are defined as non-containerized accumulations of solid, non-
flowing CCR placed on land. This classification subjected piles of CCR
to the same regulatory criteria as CCR landfills unless they are
containerized or part of an off-site beneficial use.
In the 2019 CCR proposal, EPA proposed to unify the regulatory
mechanism for all temporary placements of CCR on land, whether onsite
or off-site, and regardless of their ultimate use for disposal or
beneficial purposes, setting the standard to control releases from
piles. The proposal aimed to provide a consistent mechanism to address
potential environmental and health issues associated with piles of CCR,
irrespective of their location or intended use, characterizing these
activities as ``storage'' rather than disposal or beneficial use. A
definition for CCR storage piles was proposed, identifying temporary
accumulations of CCR that are designed and managed to control
environmental releases.
The 2019 CCR proposal discussed how entities would need records
documenting the removal of CCR within a specific timeline and sought
comments on the feasibility of this requirement and alternative
criteria for demonstrating temporary piles. Additionally, EPA proposed
requirements to control releases from CCR storage piles. The proposal
excluded CCR stored in enclosed structures from these requirements.
5. 2020 CCR Notice of Data Availability
On December 22, 2020, EPA published a Notice of Data Availability
(NODA) titled ``Hazardous and Solid Waste Management System: Disposal
of Coal Combustion Residuals from Electric Utilities; Reconsideration
of Beneficial Use Criteria and Piles; Notification of Data
Availability'', that announced the release of new information and data
related to its proposed rule published concerning CCR (85 FR 83478,
December 22, 2020) (2020 CCR NODA). EPA sought public comments on
whether this new data could influence the Agency's

[[Page 18976]]

reconsideration of the beneficial use definition and provisions for CCR
accumulations. The Agency specifically requested comments on these two
issues and invited additional data from the public to assist with its
reconsideration. EPA clarified that it was not reopening other aspects
of the proposal, CCR regulations, or previously available support
documents. In addition to seeking public input, EPA shared information
obtained during stakeholder meetings held between May and August 2020,
which involved discussions with trade associations, utilities,
environmental organizations, and state agencies.
6. Public Comments on the Fourth Beneficial Use Criterion and CCR
Accumulations for the 2019 CCR Proposal and 2020 CCR NODA and EPA's
Decision To Repropose
The Agency received about 130,000 total comments, including
comments from a mass mailer campaign, with 60 substantively different
sets of comments, on the 2019 CCR proposal reconsidering the beneficial
use criteria and provisions for CCR accumulations. Generally, a few
state agencies and a public interest group favored the various proposed
options to revise the beneficial use criterion, but none of the options
had universal support. Some states supported eliminating the mass-based
threshold and replacing it with some of the specific location-based
criteria to trigger an environmental demonstration which should apply
to all unencapsulated uses; and an approach combining the location- and
mass-based criteria. One state also suggested that an alternative
criterion be allowed where state programs have location-based criteria
coupled with chemical constituent limits. Other states suggested
establishing a reasonable set-back distance to water supply, especially
drinking water wells, by adopting a standard similar to North Carolina,
which uses the seasonal high groundwater table. One state noted that
removing the distinction between coal ash disposal and beneficial use
could result in authorization requirements for beneficial use
activities, such as permits or registrations; and suggested the Agency
continue to encourage CCR beneficial use activities through self-
implementing environmental protections with minimal to no permit
requirements. Industry and environmental groups generally opposed the
proposal to eliminate and replace the mass-based threshold with
location-based criteria. The CCR users and utilities commented that the
proposed revisions, including having to conduct an environmental
demonstration, would discourage the beneficial use of CCR because of
perceived liability concerns and financial burdens to the beneficial
user. Industry also commented that changing to location-based standards
from a mass-based approach shifts away from the Agency's original
concern when the use of unencapsulated CCR on the land should require
further demonstration that the use was not disposal and brings in
smaller volume beneficial uses. The environmental groups commented that
the proposed location-based criteria would weaken the current
regulations by allowing any amount of unencapsulated CCR to be placed
on the land as beneficial use.
Regarding EPA's 2019 CCR proposal to unify the regulatory mechanism
for all temporary placements of CCR in piles, industry representatives,
a state agency and the Association of State and Territorial Solid Waste
Management Officials (ASTSWMO) supported consistent regulatory
treatment and a single set of requirements regardless of the location.
Regarding the requirement to control releases, utilities and CCR
users expressed concern about subjecting all piles, regardless of size,
to the same set of storage standards. However, they supported the
flexibility to choose pollution control measures that are site-specific
and appropriate for conditions at the site. In contrast, environmental
groups disagreed with this flexibility, requesting instead prescriptive
design standards, management controls and engineer certification.
Many commenters, including states, CCR users and utilities, agreed
that long-term storage of CCR in lieu of disposal should not be
allowed. Nonetheless, CCR users and utilities disagreed with the
proposed record-keeping requirements to document the complete removal
of CCR within a specific timeline. For storage sites not in proximity
to end use, the industry requested that record-keeping be limited to
gross annual receipts and shipments of CCR. For sites near working end-
use locations, such as cement kilns, concrete plants, wallboard
manufacturing facilities, commenters argued that locations should
sufficiently indicate their active status. Some states and utilities
argued that any temporal requirements should better reflect the rolling
basis of storage activities or be modeled after RCRA subtitle C
speculative accumulation requirements. Environmental groups argued for
increased enforceability and specificity through enforcement of exact
timeframes.
Regarding the enclosed structure, beneficial users argued that the
proposed definition is not workable and should be revised to enable CCR
to be received and removed easily while ensuring effective containment.
Environmental groups supported the proposed requirement for enclosed
structures but also requested additional requirements to containerize
liquids and specific requirements for fugitive dust control. They
argued that engineer certifications were also needed for enclosed
structures and that owners must be required to conduct maintenance,
inspections and repairs.
On the follow-up 2020 CCR NODA, the Agency received 33 total
comments. Several commenters resubmitted comments previously submitted
to the Agency's 2010 CCR proposal. Generally, industry groups
representing different manufacturing or production industries commented
that CCR is a valuable input--these include cement and concrete
producers, gypsum panel product manufacturers, and agricultural
sectors. Industry also commented on the absence of damage cases
associated with piles, and any beneficial use that meets the first
three beneficial use criteria, concluding the fourth criterion is
unnecessary. Environmental groups and citizens commented generally that
piles, fill, and other unencapsulated uses involving land placement and
having substantial environmental and human health impacts, can be open
dumping of CCR without applicable disposal regulations.
EPA has considered all significant and relevant comments related to
revising the fourth criterion of the beneficial use definition, and
other issues related to beneficial use, as well as comments related to
the regulation of CCR accumulations on the land that were submitted in
response to the 2019 CCR Proposal and the 2020 NODA and has taken those
comments into account in developing this re-proposal. If any commenter
believes their previous comments on the definition of beneficial use
and CCR accumulations have not been adequately addressed by this re-
proposal, EPA requests the commenter re-submit their comment to this
docket.

IV. What is EPA proposing?

EPA is proposing to amend the federal regulations governing the
disposal of CCR in landfills and surface impoundments and defining
beneficial use for CCR in 40 CFR part 257. In response to the
information EPA has received during the rulemaking for the Legacy Final
Rule and since the rule's publication, EPA is proposing several
revisions to the existing federal CCR

[[Page 18977]]

regulations, which are self-implementing or implemented under a
participating-State CCR program. Specifically, EPA is exempting CCR
dewatering structures from regulation under part 257 and modifying the
legacy CCR surface impoundment and CCRMU provisions.
Additionally, EPA is proposing to establish a new compliance
pathway that allows for site-specific considerations during permitting
for CCR units complying with groundwater monitoring, corrective action,
and closure requirements under a federal or participating-State CCR
permit. Specifically, these provisions would allow a permit authority
to make site-specific determinations regarding the appropriate point of
compliance for the groundwater monitoring system, site-specific cleanup
levels during corrective action for constituents without a federal MCL
established under Sec. Sec. 141.62 and 141.66 and referenced at Sec.
257.95(h)(1), and appropriateness of certain closure requirements while
still requiring the owner or operator to ensure the unit poses no
reasonable probability of adverse effects on human health and the
environment.
Lastly, EPA is proposing to revise the definition of beneficial use
by eliminating the requirement for an environmental demonstration for
the non-roadway use of more than 12,400 tons of unencapsulated CCR on
land, as well as proposing a definition of CCR storage pile, and
proposing to exclude specific beneficial uses from federal CCR
regulations.
In addition to the proposals above, EPA is providing notice that in
a future separate action, EPA will reopen the public comment period for
the Federal CCR permit program proposed rule entitled Hazardous and
Solid Waste Management System: Disposal of Coal Combustion Residuals
From Electric Utilities; Federal CCR Permit Program (85 FR 9940) for a
period of 30 days. The public comment period ended on that proposal on
August 7, 2020. EPA will reopen the comment period in a future separate
action under Docket ID No. EPA-HQ-OLEM-2019-0361 to provide the public
with an opportunity to provide input on whether their views of the
proposed Federal CCR Permit Program have altered in the intervening
years, for example, in light of new information or considering the
revisions proposed in this action.

A. Amendments to the Self-Implementing Regulations

As discussed in Units III.A. and III.D. of this preamble, the 2015
CCR Rule established national requirements for CCR disposal under a
self-implementing regulatory structure. Since the promulgation of the
2015 CCR Rule, the 2016 WIIN Act authorized EPA to approve State CCR
permit programs and implement a permit program for EPA to serve as the
permit authority. 42 U.S.C. 6945(d). In accordance with RCRA sections
4005(d)(3)(A) and 4005(d)(6), in the absence of a permit issued under a
participating-State program, the owner or operator of a CCR unit must
continue to comply with the self-implementing Federal CCR regulations
until a permit from a CCR permit authority (i.e., an EPA-approved State
CCR permit program or EPA) that includes these provisions is in effect.
42 U.S.C. 6945(d)(3)(A), (d)(6). For a State with an approved CCR
permit program (i.e., Oklahoma, Georgia, Texas, North Dakota), before
the State can issue a permit or permit modification for a CCR unit that
operates in lieu of the amended regulations from this rulemaking, the
State must adopt either the federal standards or alternative technical
standards that are at least as protective as the amended Federal CCR
regulations, submit an application for approval of the new provisions
to the Agency, and receive EPA approval for the new provisions. EPA
will work closely with States throughout this process to expedite
reapproval of amended provisions.
Since publication of the Legacy Final Rule, EPA received
information from numerous companies and representatives of industry
regarding the scope of the deferrals within the Legacy Final Rule, the
scope of the CCRMU universe, challenges complying with the existing CCR
requirements, and requests for regulatory changes. Based on this
information provided to EPA, as described in greater detail below, and
the conclusions described in Unit III.D., EPA is proposing several
amendments to the existing CCR requirements. Specifically, EPA is
proposing to: define and exempt CCR dewatering structures from
regulation under part 257; broaden the criteria for the closure by
removal certification for legacy CCR surface impoundments; broaden the
deferral criteria for legacy CCR surface impoundments that have
completed closure under a regulatory authority prior to November 8,
2024; amend the scope of the CCRMU regulations; and clarify the
deadline for new CCR landfills, CCR surface impoundments, and lateral
expansions to comply with the requirements to conduct background
sampling. EPA is also soliciting comment on several provisions,
including on the need to finalize the 2018 proposed performance
standard for more specific slope protection requirements for existing
and new surface impoundments.
1. CCR Dewatering Structures
EPA is proposing a definition for ``CCR dewatering structures'' at
Sec. 257.53 and making other clarifying edits to Sec. 257.53 to
explicitly state that a dewatering structure meeting this definition
would not be classified as a CCR surface impoundment or a CCRMU. During
implementation of the CCR program, questions have arisen as to the
appropriate standards that should apply to certain concrete basins used
as settling ponds for CCR.\5\ Specifically, owners or operators have
expressed uncertainty regarding whether dewatering structures are
subject to the surface impoundment requirements in the existing federal
CCR regulations and have argued that the surface impoundment
regulations are unnecessary. While EPA previously took the position
that, under the current regulations, these structures are surface
impoundments,\6\ EPA has reconsidered that position and believes that
regulation as CCR surface impoundments is inappropriate based on a
reevaluation of the risk these structures present. This proposal will
provide greater flexibility by revising the regulation to provide that
these structures: (1) Are not CCR surface impoundments and are CCR
dewatering structures as defined in this proposal and (2) As CCR
dewatering structures, are not regulated under the federal CCR
regulations.
---------------------------------------------------------------------------

\5\ PacificCorp 2025a. Letter from Brett Shakespear, Director,
Environmental Compliance and Remediation to Linda Jacobson, EPA
Region 8 RCRA Enforcement Section. Re: NEIC Civil Investigation
Report Hunter Power Plant, Castle Dale, Utah. October.
\6\ See, for example, Electric Energy, 106 F.4th 31, 42 (2024).
---------------------------------------------------------------------------

The containment structures in question are used for dewatering CCR
to enable CCR solids to be landfilled and are commonly referred to as
holding basins, scrubber drying basins, fly ash washdown basins, tanks,
or settling ponds. Under the proposed definition, CCR dewatering
structures are designed to temporarily contain an accumulation of CCR
and therefore involve storage, rather than disposal, for the purposes
of the CCR regulations. See definition of ``disposal'' in Sec. 257.53,
which states, ``For purposes of this subpart, disposal does not include
the storage or the beneficial use of CCR.'' Based on the Agency's work
with CCR, it is EPA's current understanding that the use of CCR
dewatering structures is a common

[[Page 18978]]

practice across the industry. In fact, the use of dewatering structures
is necessary if CCR is to be landfilled. The dewatering process,
including the use of these structures, plays a critical role in
efficiently managing CCR by reducing moisture content, thereby
facilitating easier handling. Dewatering typically serves as an interim
step, or steps, prior to disposal in a landfill or shipment for
beneficial use. Dewatering structures are specifically engineered to
allow for the CCR to dry and result in CCR being easier to handle when
moving to disposal in a landfill or being beneficially used. Typically,
these structures are made of concrete or other similar material. Their
purpose is to dewater wet CCR, not to serve as long-term storage or
disposal of CCR. Given this use and function, EPA is now concluding
that CCR dewatering structures are different from surface impoundments
due to the fundamental differences in their design and function.
Surface impoundments usually involve the long-term containment of
liquid waste, typically with a significant hydraulic head, which poses
a higher risk of seepage and contamination of groundwater resources.
Periodically, once sufficient dewatering has occurred, the CCR in these
structures will be removed and transported to a CCR or permitted MSW
landfill or beneficial use location--another key distinction from
surface impoundments that was not fully recognized during the prior
rulemaking. As such, clarifying the regulatory status of these
dewatering structures is appropriate in this rulemaking.
To create a clear regulatory separation between these CCR
dewatering structures and CCR surface impoundments, EPA is proposing to
create a new definition for ``CCR dewatering structures'' in 40 CFR
part 257. EPA proposes to define CCR dewatering structures as ``a
stationary device, designed to temporarily contain an accumulation of
CCR which is constructed of non-earthen materials (e.g., concrete,
steel, plastic). The device must be used primarily for dewatering CCR
waste to facilitate disposal of CCR solids elsewhere.'' Accordingly,
and to provide greater clarity, EPA also proposes to amend the
definition of CCR surface impoundment to note that a containment
structure meeting this newly proposed definition of a CCR dewatering
structure is not a surface impoundment.
In addition to more appropriately calibrating the level of
regulation that is appropriate for these structures, this proposed
change enables more owner or operators to dewater their CCR prior to
disposal (i.e. landfilling the CCR instead of disposal in surface
impoundments). The landfill in which the CCR is ultimately disposed
must meet all applicable part 257 or 258 requirements.
EPA expects this change would not produce a reasonable probability
of adverse effects on health or the environment. This expectation is
informed by a reconsideration of determinations in the initial 2014
Risk Assessment as well as EPA's understanding of the size and use of
these structures. During the 2015 CCR Rule, EPA considered related
issues which EPA has since reevaluated. First, EPA considered whether
the definition of a CCR surface impoundment should include
``temporary'' units that are not designed to hold an accumulation of
CCR such as downstream secondary and tertiary surface impoundments,
such as polishing, cooling, wastewater and holding ponds. EPA reasoned,
at the time, that those units are unlikely to ever be completely
dredged of CCR and are likely to have large quantities of CCR impounded
with water under a hydraulic head will be managed for extended periods
of time. As such, EPA concluded, these units present the same risks as
permanent disposal units. (50 FR 21357) Second, in the risk assessment
supporting the 2015 CCR Rule, EPA modeled units with concrete liners as
equivalent to unlined units because of the expectation that cracks
could lead to uncontrolled leakage and the difficulties of repairing
any issues with the concrete liner.
However, with specific real-world examples arising during
implementation, EPA is reconsidering some of these conclusions. First,
EPA notes that these conclusions do not account for the fact that
concrete containment structures would, by design and function normally
be much smaller than a CCR surface impoundment. The several examples of
CCR dewatering structures of which EPA is currently aware range from
approximately 0.02-2.2 acres in size. The average size of these
structure is 0.77 acres with thea median size of 0.4 acres.\7\ By
comparison, the average and median size of CCR surface impoundments
regulated under the 2015 CCR Rule is 54.2 and 24.0 acres, respectively.
While surface impoundments do vary widely in size, on average they are
considerably larger than a CCR dewatering structure.\8\ The smaller
amount of CCR that is accumulated in these structures along with the
lower hydraulic head resulting from the significantly smaller unit size
suggests the risk to be lower, with other conditions remaining the
same. Further, the EPA acknowledges the previous determination that
concrete containment structures were equivalent to unlined units was
not based on actual data of leakage rates from concrete containment
structures.
---------------------------------------------------------------------------

\7\ See Memo to record re: CCR dewatering structures. January
2026.
\8\ See 89 FR 38958 for a discussion of available information on
various CCR unit sizes.
---------------------------------------------------------------------------

The information available to EPA indicates these structures are
made of concrete and are enclosed on three sides with a concrete bottom
liner. The bottom liner covers the entire surface that may come in
contact with CCR containing liquid during the dewatering cycle. This
fact distinguishes these structures from unlined units or units only
partially lined with concrete (e.g., employing a concrete revetment mat
or employing only a concrete apron and vehicle ramp).
These concrete dewatering structures are designed for temporary
accumulation and are periodically dredged, and CCR removed. As
discussed above, the management practices typically conducted in these
structures would not meet the definition of ``disposal'' and no long-
term encapsulation or containment of CCR is expected to occur in these
structures. Under the proposed definition of these units, only the
temporary containment of an accumulation of CCR for ``for disposal
elsewhere'' would occur. The structures are utilized in a process step
(dewatering) critical to efficiently managing CCR by reducing moisture
content, thereby facilitating easier handling. Dewatering in these
structures serves as an interim step, or steps, prior to disposal in a
landfill or shipment for beneficial use. Dewatering structures are
specifically engineered to allow for the CCR to dry and result in CCR
being easier to handle when moving to disposal in a landfill or being
beneficially used. As such, at the end of their life no CCR should
remain in the containment structures. EPA also expects the periodic
dredging and emptying of the dewatering structures at the end of each
dewatering cycle will provide an opportunity for some visual inspection
of the structures to identify significant cracks or other failures in
the engineered structure. Based on EPA's understanding, these
distinctions suggest a lower risk for these structures than EPA
estimated in the 2014 Risk Assessment.
Additionally, EPA now also has a greater appreciation for the
various standards used in the concrete industry. For example, the
American Concrete Institute has standards and commentary

[[Page 18979]]

for concrete structures used in environmental engineering. The
standards cover the structural design, materials selection, and
construction of environmental engineering concrete structures. The
standards account for the fact that concrete structures used for
conveying, storing, or treating liquid or solid wastes are subject to
uniquely different loadings, more severe exposure conditions, and more
restrictive serviceability requirements than non-environmental building
structures.\9\ While these standards are not legally binding, they
illustrate the expertise in the concrete industry and the refinement of
concrete formulations, and methods for specific applications. Notably,
the commentary provides substantial guidance and best practices to
assure liquid-tightness of concrete structures.\10\
---------------------------------------------------------------------------

\9\ American Concrete Institute. ``Code Requirements for
Environmental Engineering Concrete Structures (ACI 350-06) and
Commentary'' 2006.
\10\ Ibid, pg. 350-3.
---------------------------------------------------------------------------

Furthermore, developments in material science have yielded
advancements in concrete technology. A 2023 review of available
literature concluded that concrete technology had undergone remarkable
advancements in the preceding decade, encompassing novel materials,
sustainable practices, durability enhancements, and advanced
manufacturing techniques. The review notes the developments offer
improved performance, sustainability, and construction efficiency. The
review also concluded that the introduction of novel materials, such as
additives, fibers, and fillers, has led to enhanced properties in
concrete, including increased strength, ductility, and crack
resistance.\11\ A 2025 study also found that self-healing concrete
formulations improve concrete structure longevity. Specifically, the
authors of the study found high crack healing efficiency in self-
healing concrete that can also extend service life of concrete
structures.\12\ Based on its experience with these industries, EPA
expects owners or operators will have incorporated recognized and
generally accepted good engineering practices in the design and
construction of these structures. Therefore, EPA likely overstated the
risks in 2014 of these comparatively small units with concrete liners.
EPA is thus proposing these containment structures be considered CCR
dewatering structures, not CCR surface impoundments and that they are
not subject to the requirements for surface impoundments in 40 CFR part
257, subpart D.
---------------------------------------------------------------------------

\11\ Ajwad, A (2023) Concrete Evolution: An Analysis of Recent
Advancements and Innovations. Fifth Conference on Sustainability in
Civil Engineering (CSCE'23) Department of Civil Engineering Capital
University of Science and Technology, Islamabad Pakistan. <a href="https://csce.cust.edu.pk/archive/CSCE_23_conference_proceedings/2023-135.pdf">https://csce.cust.edu.pk/archive/CSCE_23_conference_proceedings/2023-135.pdf</a>.
\12\ Olaboye, O. S. (2025) Advancements in Self-Healing
Concrete: Enhancing Durability and Reducing Maintenance Costs.
American Journal of Engineering Research, Vol 14 (issue 2) pp 25-34.
---------------------------------------------------------------------------

In implementation, the key to distinguishing these dewatering
structures from surface impoundments would be whether the structure in
question was: (1) Used for temporary accumulation of CCR for the
primary purpose of dewatering the CCR and (2) Built with non-earthen
materials. If the containment structure meets both criteria above, it
is considered a CCR dewatering structure under 40 CFR part 257. If not,
the structure would be a CCR surface impoundment as defined in Sec.
257.53.
To develop a more comprehensive understanding of the prevalence and
nature of structures that would meet the proposed definition of a CCR
dewatering structure, EPA is soliciting comment on the number of
structures that meet the proposed definition and their locations. EPA
specifically requests information about: (1) the location of these
structures, including the state, facility name, and precise location at
the facility, (2) specifics about the design, including if professional
engineer certified the designs, the size of the unit, and expected
operational life, (3) specifics about the construction, including the
date of construction and materials used, (4) specifics about the
materials that were used, including any relevant standards or
specifications for the material (e.g., ASTM or ACI), (5) any expected
or routine maintenance required to keep the structure operating as
intended, including specifics regarding the maintenance performed and
the frequency, and (6) specifics about the operation of these
structures (e.g., average dewatering cycle times, frequency of
inspections conducted, or any other relevant information).
Additionally, EPA requests information on the environmental regulation
and impact of these structures, including any known incidents of
leakage or contamination, state or local oversight of these units, or
monitoring or reporting mechanisms in place. Further, EPA requests
comment on what, if any, additional criteria should be incorporated
into the proposed definition of CCR dewatering structures. For example,
should the definition of CCR dewatering structure specify the structure
be completely enclosed on three sides or that the non-earthen material
have a hydraulic conductivity of no more than 1 x 10-7 cm/
sec, as required for composite or alternative composite liners for new
CCR units? See Sec. 257.70(b) and (c). Should the definition require
the unit be located in a location whereby any releases would be
detected by the facility's groundwater monitoring system (i.e., covered
as part of a multi-unit system)? Should the definition include certain
operational standards or practices that would need to be adhered to in
order to be a CCR dewatering structure, such as: routine visual
inspection of the concrete structure (i.e., at the end of every
dewatering cycle) to identify and address visually apparent cracks,
spalls, or issues with sealants and joint condition to help ensure the
liquid tightness of the concrete structure; daily inspections of
ancillary equipment (e.g., piping, valves, pumps) to help prevent
leaks, spills or overtopping caused by equipment failure or human
error; maintaining a minimum freeboard throughout the dewatering cycle
to prevent overtopping and associated potential runoff; or biennial
cleanouts of the structures including pressure washing to decontaminate
the unit and allow for more detailed inspection and repair of the
concrete slab and joints to ensure liquid tightness of the concrete and
greatly reduce the risk of leaking? EPA requests comment on whether
these operational requirements would be appropriate or necessary to
ensure no adverse effect on health and the environment as part of
exempting these units from regulation as CCR surface impoundments.
Finally, to provide as clear a definition as possible, EPA also
requests comment on the proposed definition of CCR dewatering
structure. EPA specifically solicits feedback regarding how to better
distinguish between these temporary dewatering structures and composite
lined surface impoundments, such as incorporating explicit parameters
regarding what constitutes ``temporary'' containment of an accumulation
of CCR. If so, EPA request input regarding the specifics of those
parameters (e.g., what length of time should constitute ``temporary'').
This information is anticipated to help the Agency validate or
calibrate its proposed approach (i.e., exempting these CCR dewatering
structures from Federal regulation as a CCR surface impoundment). The
Agency believes this is worthwhile given that most of the information
EPA currently has on these structures are from a relatively small
subset of facilities compared to the total universe. Gathering broader
data will help ensure that the decision in the final

[[Page 18980]]

rule considered a more comprehensive set of information.
2. Legacy CCR Surface Impoundments
Since publication of the Legacy Final Rule, EPA has received
information from States and regulated entities about the adequacy of
closures of legacy CCR surface impoundments and CCRMU completed prior
to November 8, 2024.\13\ These entities have stated that this
information demonstrates that closures performed under State oversight
are protective of human health and the environment. Therefore, EPA is
proposing to create another option in Sec. 257.100(g) for owners and
operators to certify closures of legacy CCR surface impoundments by
removal that have been completed prior to November 8, 2024 and to
expand the deferral criteria in Sec. 257.101(g) for legacy CCR surface
impoundments and CCRMU that completed closure prior to November 8, 2024
under oversight by a regulatory authority (i.e., State or federal
program).
---------------------------------------------------------------------------

\13\ This is the effective date of the Legacy Final Rule.
---------------------------------------------------------------------------

a. Certification of Closure by Removal for Legacy CCR Surface
Impoundments
EPA is proposing to establish an additional option in Sec.
257.100(g) for owners and operators to certify the closure of legacy
CCR surface impoundments by removal, provided these closures were
completed prior to November 8, 2024, under the oversight of a
regulatory authority.
The Legacy Final Rule established a pathway for legacy CCR surface
impoundments that closed by removal before November 8, 2024, allowing
them to certify and document their closure as having met the
performance standards in Sec. 257.102(c) See Sec. 257.100(g).
Successfully documented and certified closures by removal would exempt
these legacy surface impoundments from further requirements under 40
CFR part 257, subpart D. This decision was made to avoid requiring
owners or operators of legacy surface impoundments that had completed
closure in a manner that met the performance standards in Sec.
257.102(c), to comply with additional subtitle D requirements which
would not result in health or environmental benefits. Under the
regulations promulgated at Sec. 257.100(g), the following information
is required to make the certification:
<bullet> The type and volume of CCR and all other materials in the
unit prior to closure;
<bullet> The methods used to verify complete removal of all CCR and
other contaminated materials from the unit, including any post-removal
sampling and analysis;
<bullet> Documentation that all CCR and other contaminated
materials were removed from the unit, including, the results of any
post-removal sampling and analysis that was conducted;
<bullet> The methods used to verify complete decontamination of all
areas affected by releases from the unit, including but not limited to
post-decontamination sampling and analysis;
<bullet> Documentation that all areas affected by releases from the
unit were decontaminated and that all groundwater affected by releases
has achieved groundwater protection standards; and
<bullet> Documentation that groundwater monitoring data
concentrations of each appendix IV constituent do not exceed the
relevant groundwater protection standard, which would be either the
federal MCL or background concentration, for two consecutive sampling
events, consistent with Sec. Sec. 257.95(e) and (h). Additionally, the
owner or operator must include documentation that the system meets a
subset of performance standards at Sec. Sec. 257.91(a) through (e),
257.93(a) through (d), and 257.93(i) codified at Sec. Sec.
257.100(g)(6)(i) through (vii).
This avenue to closure by removal certification for legacy
impoundments is a viable path for some legacy surface impoundments, in
particular, units that had groundwater monitoring systems and data to
demonstrate constituent concentrations do not exceed the groundwater
protection standard established at Sec. 257.95(h). The Agency intends
for this avenue to remain in effect and is not proposing to revise this
provision. Maintaining this avenue avoids potential disruption for
owners and operators that have already made such demonstrations.
However, several public comments on the Legacy Proposed Rule
requested greater flexibility in closure by removal certification for
legacy impoundments, specifically advocating for all closures by
removal approved by a State or regulator under other authorities (e.g.,
State solid waste programs) to also qualify for certification. During
finalization of the Legacy Final Rule, EPA did not adopt this
suggestion due to a lack of documented factual and legal basis for
States' decisions, which prevented EPA from concluding that all State-
approved closures by removal posed no reasonable probability of adverse
effects on health or the environment, as mandated by RCRA section
4004(a). (89 FR 39009) While concluding all State-approved closure met
the RCRA protectiveness standard was not appropriate, EPA acknowledges
that additional flexibility in the closure by removal certification
criteria may be warranted in certain instances.
Since publication, EPA has received information from members of the
regulated community to support the expansion of the closure by removal
certification criteria and the conclusion that closure performed under
State oversight meets the RCRA protectiveness standard. Upon
reconsideration, EPA reviewed pertinent information, including public
comments on the Legacy Proposed Rule, and the information received
post-finalization of the Legacy Final Rule, including examples of
State-overseen closures in Kentucky, North Carolina, South Carolina,
and Georgia.
In Kentucky, the State's Division of Waste Management (KDWM)
oversaw the closure by removal of three legacy impoundments at the Dale
power generation facility between 2014 and 2019. KDWM approved the
closure plan, conducted at least 16 onsite inspections including three
inspections of the units to verify ``clean closure'' down to native
soils. KDWM spent over 350 hours overseeing the closure.
At Duke's Riverbend plant, North Carolina required and oversaw the
closure by removal of 5.35 million tons of CCR between 2014 and 2019.
The impoundments were dewatered, the ash excavated, and the area
regraded and seeded with grass. The State also requires annual
stability inspections, a groundwater monitoring program with over 140
wells, and a corrective action program to continue at the two now
closed legacy impoundments. EPA independently verified that North
Carolina's Coal Ash Management Act (CAMA) requires closure of all
unlined impoundments, including those at inactive facilities that would
qualify as legacy CCR surface impoundments. Further, review of publicly
available documentation from Duke Energy, the owner of all legacy
impoundments in the state, indicates the presence of state orders-on-
consent requiring corrective action for these units.
Between 2012 and 2020, South Carolina oversaw the closure by
removal of two CCR surface impoundments at the Granger facility. The
owner or operator removed all the CCR along with an additional foot of
underlying soil from both inactive impoundments. The removal of CCR
from the two impoundments was performed under the supervision of the
South Carolina Department of Health and Environmental Control (SCDHEC)
and in accordance with the requirements established by a detailed CCR
closure

[[Page 18981]]

plan also approved by SCDHEC. The closure plan also required
comprehensive soil sampling to ensure the decontamination of the
remaining soil across both impoundments. Post-closure groundwater
monitoring--required by the State--will continue until all relevant
constituents meet, and stabilize at or below, their applicable MCL, as
established by SCDHEC. EPA's own research found that the legacy CCR
surface impoundments in South Carolina are already undergoing or have
undergone closure and, if needed, corrective action consistent with the
requirements of the legacy rule.
In a fourth example of information provided to EPA regarding
closure by removal of legacy CCR surface impoundments under State
oversight, Georgia oversaw the closure by removal of an ash pond at the
Kraft plant through the State's Response and Remediation Program
between 2015 and 2021. The State approved the soil and groundwater at
the unit as protective of human health and the environment in 2021. EPA
also received comments on the Legacy Proposal that offered a few
examples of closures that the commenters believed were substantially
equivalent to closures completed in accordance with Sec. 257.102,
because they involved substantial regulatory oversight, a site-specific
risk assessment, and general consistency between the programs on the
standards to be applied. These included closures under the
Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) and an approved State's RCRA subtitle C program. Another
commenter, Duke Energy, provided a copy of a 2020 Consent Order entered
in State court governing the closure of CCR surface impoundments at
seven sites across the State. The utility also provided copies of
several human health and ecological risk assessments that were
conducted to support the State's approval of the closures, along with
various third-party reports. The commenter concluded that based on this
record, it is unnecessary to subject CCR units that closed under any
other regulatory programs to the existing closure criteria for CCR
surface impoundments in Sec. Sec. 257.101 and 257.102. While these
examples aren't specific to closure by removal, the commenters were
intending to illustrate that these other regulatory authorities provide
detailed and meaningful oversight to address risk posed by the CCR
units in a site-specific, tailored approach and therefore, additional
Federal requirements are not necessary and would not result in health
or environmental benefits.
As stated in the Legacy Final Rule, EPA agrees that closures
conducted as part of a CERCLA or RCRA subtitle C response action would
normally be expected to be consistent with the performance standards in
Sec. 257.102. The CCR closure regulations were based on the closure
regulations for hazardous waste facilities, and the CCR regulations
would normally be considered applicable or relevant and appropriate
requirements (ARARs) under CERCLA for any closure of a CCR facility
after 2015. EPA further acknowledged that these closures are not the
only closures that may be equally as protective as those conducted
under the Federal CCR requirements. (89 FR 39030).
In the Legacy Final Rule, EPA finalized requirements to monitor
groundwater to ensure the closure fully addressed any risk to the
groundwater. However, based on the information provided to EPA
regarding the level of regulatory oversight during and after these
previous closures, and the cases made by commenters regarding the
ability of permit authorities to adequately address risk in a site-
specific way, EPA now concludes that requiring groundwater monitoring
is not the only way to assess potential risk to groundwater and ensure
closures pose no reasonable probability of adverse effects to health
and the environment. For example, a State may have overseen the closure
by removal of a legacy surface impoundment and determined, based on
state legislation, risk assessments, site-specific facts, or models,
that groundwater monitoring was not necessary to conclude that the
closure did not pose a reasonable probability of adverse effects to
health or the environment. Such a unit would not be eligible to certify
the closure by removal under the current regulations. However, EPA
concludes that additional closure activities are not warranted as long
as the impacts to groundwater were considered prior to or during the
closure, even if the authority determined groundwater monitoring was
not necessary.
This pathway to closure by removal certification ensures no
reasonable probability of adverse effects on health or the environment,
in part, by requiring state oversight of previously conducted closures
by removal. State oversight of the closure by removal should ensure
that all CCR were removed from the surface impoundment and, thus, no
source of contamination would remain at the unit. This pathway thus
ensures the sources of additional pollution were eliminated. The
pathway, additionally, provides for consideration of groundwater and
state oversight of any necessary corrective action. Identified existing
contamination (i.e., that originating prior to all CCR being removed)
could be addressed by corrective action, as deemed necessary by the
state.
Therefore, based on the above considerations and information, as
well as the conclusions discussed in Unit III.D. regarding the ability
of EPA to allow for non-uniformity in attainment of the baseline RCRA
standard of protection, EPA is proposing to codify another option for
owners and operators to certify closure of legacy CCR surface
impoundments by removal at Sec. 257.100(g).\14\ Under this option,
owners or operators must demonstrate the closure was completed under
the oversight of another regulatory authority prior to November 8,
2024, the authority considered impacts to the groundwater, and oversaw
any necessary corrective action. Adding a third avenue for
certification of closure by removal for legacy surface impoundments
that have completed closure by removal under state or Federal oversight
prior to November 8, 2024, credits owners and operators' good faith
efforts to comply with closure requirements for legacy surface
impoundment imposed by other regulatory authorities prior to the Legacy
Final Rule's effective date. Additionally, this avoids duplicative
regulation that could cause uncertainty, delay, or require redoing
closure work that was approved by another regulatory authority. The
proposed change would address the state closure scenario described
above and others where a State or other regulatory authority--during
the active oversight of the legacy CCR surface impoundment closure--
determined the closure by removal would not present a reasonable
probability of adverse effects to health or the environment, even
without requiring groundwater monitoring.
---------------------------------------------------------------------------

\14\ The regulations already contain two pathways for owners and
operators of legacy surface impoundments to certify closure by
removal (i.e., Sec. 257.100(g)(1)-(6) for those with available
groundwater data and Sec. 257.100(h) for those units that needed to
conduct additional groundwater monitoring). This proposal would not
affect these two existing certification avenues. The proposed third
avenue for certification of closure by removal is an additional
avenue not intended to disrupt, supersede, or otherwise alter the
two existing avenues.
---------------------------------------------------------------------------

To effectuate this change, EPA is proposing to modify Sec.
257.100(g) to provide another avenue to certify the closure by removal
for legacy surface impoundments. This proposal would not affect those
who completed the certification under the existing

[[Page 18982]]

regulations no later than November 8, 2024. If finalized, this proposal
would provide the option for an owner or operator of a legacy CCR
surface impoundment that completed closure of the CCR unit by removal
of waste prior to November 8, 2024, to complete a closure certification
that includes information regarding a regulator-approved closure by
removal and any necessary corrective action conducted pursuant to an
enforceable requirement. The documentation would need to demonstrate
that the regulator played in active role in overseeing and approving
the closure by removal, considered impacts to groundwater, and oversaw
and approved any necessary corrective action. The consideration of
groundwater impacts is important to ensure that the potential risks to
groundwater were evaluated by the State or other regulatory authority.
This may take the form of site-specific information (e.g., groundwater
monitoring data, receptor surveys, groundwater modeling, or a risk
assessment) or statewide decision that groundwater monitoring is not
necessary (e.g., state legislation stating as much). Instances of a
regulatory authority providing active oversight and approval of a
closure could include closure by removal conducted under a State or
Federal permit, an administrative order, or consent order issued on
after October 19, 2015 under CERCLA or by an EPA-approved RCRA State
program.
The October 19, 2015 date is the effective date of the 2015 CCR
Rule which established national standards for CCR management, including
closure. EPA believes this date is appropriate as the owners and
operators conducting these closures, and regulators overseeing the
closures, would have been cognizant of the Federal CCR closure
standards. Moreover, for orders issued under CERCLA after that date,
the Federal CCR management standards would have been ARARs. As such,
this date helps ensure that the closures conducted under these
alternate programs are unlikely to result in a reasonable probability
of adverse effects on health and the environment.
EPA is proposing to require the certification of closure by removal
under the oversight of a regulatory authority including the supporting
information, be completed within six months of the publication date of
the final rule, if finalized. This compliance timeframe was used for
the original closure by removal certification at Sec. 257.100(g). EPA
expects this will provide ample time for owners and operators to
prepare the necessary documentation of State oversight of their closure
by removal.
In acknowledgement of the additional information received, and to
realize the benefits described above, this proposal allows owners and
operators to rely on prior determinations of the State and other
regulatory authorities to meet the federal standards. At the same time,
due to the practical limitations and inherent uncertainty related to
the record, EPA requests comment on the adequacy of the record for this
aspect of the proposal, and, to the extent any gaps are identified,
requests suggestions for sources of additional information. As
described above, during the rulemaking for the Legacy Rule, the Agency
had received information to demonstrate that previous closure decisions
made under State or other regulatory authorities will protect human
health and the environment. Since promulgation of the Legacy Final
Rule, the Agency received additional information describing a handful
of State programs and several individual, site-specific closure
decisions. EPA requests comment on whether these closures are
representative of closures performed at other sites and in other
States. Specifically, EPA would like to know if there is additional
information the Agency should consider, or other issues of which EPA
should be aware. For example, EPA encourages commenters to submit
specific case studies or examples where State or other regulatory
authority decisions have been effective or ineffective in ensuring
protective closures. Additionally, EPA seeks empirical data or studies
that compare the effectiveness of State and federal CCR closure
requirements or information describing specific elements of State
regulatory frameworks that may differ from federal requirements and how
these differences impact closure outcomes. EPA will consider such
information submitted as it develops the final action.
Based on this additional information and the policy rationale
described above, EPA is proposing to provide an additional option for
owners and operators to certify closure of legacy CCR surface
impoundments by removal, provided they were completed under the
oversight of another regulatory authority.
Solicitation of comment. Additionally, EPA is requesting comment on
whether the proposed additional certification of closure by removal
avenue allows for legacy impoundments to have been closed under a
sufficiently broad suite of scenarios. As described above, the proposed
approach would require the owner or operator of a legacy impoundment to
submit documentation that a regulatory authority played an active role
in overseeing and approving the closure by removal and any necessary
corrective action, pursuant to an enforceable requirement issued on or
after October 19, 2015. This includes a State or Federal permit, an
administrative order, or consent order under CERCLA or by an EPA-
approved RCRA State program.
However, during the development of the proposed rule, EPA received
input from a subset of utilities requesting a broader suite of former
closures be eligible for this certification process. One utility
requested EPA to remove the requirement that the closure and any
necessary corrective action be pursuant to an enforceable requirement.
This change would allow legacy impoundments conducted under voluntary
cleanup programs to be eligible for this certification pathway. A
second utility suggested removing the stipulation that the enforceable
requirements have been issued after October 19, 2015. This would allow
for closures conducted before the existence of the 2015 CCR Rule to be
eligible for the closure by removal certification. Removing these
restrictions on when the closure and corrective action were required
and the types of programs that could have overseen the closure of these
units would come with certain tradeoffs.
Benefits of this additional flexibility would include a greater
number of legacy impoundments eligible for this certification and thus
greater regulatory certainty and continuity. Units that were closed by
removal in a protective manner--regardless of timing of the closures
and whether they were closed under a voluntary program--would not be
required to conduct additional closure activities that don't offer
additional protection or benefits. The primary disadvantage is that
some of those units closed pre-2015 and under a voluntary program may
not have been closed in a comparable manner to that required under the
Federal program and possibly with no meaningful oversight. As a
practical matter, in such scenarios, there may be less documentation
available as to the closure and corrective action activities performed.
Relatedly, there may also be less assurance that all the closures
previously conducted under such broad criteria would ensure there will
be ``no reasonable probability of adverse effects on health or the
environment.'' For example, the level of oversight under voluntary
programs may vary between States and over time. In some States, the
voluntary closure may entail significant oversight, (e.g.,

[[Page 18983]]

regulator review and approval of the closure and groundwater monitoring
plans, review of groundwater monitoring data) but not necessarily in
all States or in all time periods in which these closures were
performed. At the same time, if the owner or operator could demonstrate
there was meaningful oversight of the closure and corrective action
activities conducted (which would still be required under this
alternative), it may be reasonable to assume the closure would be
protective.
EPA requests comment on whether the Agency's proposed criteria for
State and other regulatory programs is appropriate and whether the two
suggestions from commenters described here should be finalized. EPA is
also seeking comment on specific criteria that voluntary programs
should meet for units closed under their oversight to be eligible for
this certification. The Agency also requests examples of successful
closures under voluntary programs that could inform EPA's final
decision. EPA also requests if any other documentation may be
appropriate to require to demonstrate the protectiveness of closures
conducted pre-2015 or under a voluntary program. EPA will consider
public comments and, if the comments are sufficiently supportive, may
finalize these additional closure by removal certification paths.
b. Deferral of Certain Legacy CCR Surface Impoundment Closures To
Permitting
EPA is proposing changes to Sec. 257.101(g) to expand the deferral
criteria for legacy CCR surface impoundments that completed closure of
the unit under state or federal regulatory authority prior to November
8, 2024. This expansion will allow owners and operators to rely on the
decisions of State and other regulatory authorities regarding legacy
impoundment closures conducted prior to the effective date of the
Legacy Final Rule to meet the federal standards--until the CCR
permitting authority can consider, on a site-specific basis, the need
for additional closure measures to be taken. This expansion does not
eliminate the requirements for groundwater monitoring and corrective
action of releases from the unit.
In the Legacy Final Rule, EPA finalized provisions allowing owners
and operators of legacy surface impoundments to defer compliance with
the closure performance standard until the CCR permit authority could
make a site-specific decision regarding the adequacy of the closure,
provided the owner or operator could document that the unit closure met
certain conditions. This provision allowed the permit authority to
evaluate site-specific information and determine whether a closure
performed before the effective date of the Legacy Final Rule met the
appropriate part 257 closure standards. As explained in the Legacy
Final Rule, EPA did not want to require facilities that had completed
closure prior to November 8, 2024, to ``reclose'' if the closure
conducted was protective of human health and the environment and
requiring compliance with additional subtitle D requirements would not
result in health or environmental benefits. At the time of the Legacy
Final Rule, EPA recognized that some closures would have been done in a
manner that achieved a similar outcome to the closure performance
standards in Sec. 257.102, while others would not have. At the same
time, however, EPA did not believe that it could develop nationally
applicable criteria that were sufficiently precise that regulated
entities could determine whether the alternative requirements
ultimately accomplish the same environmental goals and meet the same
performance standards as the Federal requirements. Accordingly, the
Legacy Final Rule provided the avenue at Sec. 257.101(g) for owners
and operators of legacy impoundments to defer closure determinations
until the CCR permit authority could make a site-specific decision.
Specifically, the Legacy Final Rule provided that an owner or
operator of a legacy CCR surface impoundment need not demonstrate
compliance with the closure performance standards in Sec. 257.102(c)
or (d) provided they demonstrate that the closure of the CCR unit met a
specified list of standards codified in Sec. 257.101(g). These
standards are:
(1) The owner or operator of the CCR unit must document that a
regulatory authority played an active role in overseeing and approving
the closure and any necessary corrective action, pursuant to an
enforceable requirement. This includes a state or Federal permit, an
administrative order, or consent order issued after 2015 under CERCLA
or by an EPA-approved RCRA state program.
(2) The owner or operator of the CCR unit must document that the
regulatory authority required or conducted a site-specific risk
assessment prior to (or as part of) approving the closure and any
necessary corrective action.
(3) The owner or operator of the CCR unit must document that it
installed a groundwater monitoring system and performed groundwater
monitoring that meets all of the following:
(i) Was capable of accurately representing background water
quality;
(ii) Was capable of accurately representing the quality of water
passing the waste boundary;
(iii) Was capable of detecting contamination in the uppermost
aquifer; and
(iv) Monitored all potential contaminant pathways.
(4) Must document that the closed unit meets either:
(i) The performance standard in Sec. 257.60; or
(ii) The performance standard in Sec. 257.102(d)(2)(i).
(5) The owner or operator must also include a certification
statement as to the veracity of the information.
These standards are intended to ensure protectiveness at least
until the time a permit authority could evaluate the closure on a site-
specific basis to determine if the closure is as protective as those
conducted in accordance with Sec. 257.102. The existing provisions
require the owner or operator to submit a permit application to the
permit authority with sufficient information, including groundwater
data, to demonstrate the applicable closure standards had been met.
Under the existing regulations, the permit authority will then review
the information to determine whether the ``equivalency'' of the closure
has been successfully demonstrated. If EPA or a Participating State
Director determines that the closure has met the appropriate part 257
closure standard, the permit authority will issue a permit to require
compliance with applicable post-closure requirements. If the permit
authority determines that the closure does not meet the appropriate
part 257 standards, the owner or operator will be required to submit a
complete permit application and obtain a permit that contains the
specific requirements necessary for the unit to achieve compliance with
the closure requirements at Sec. 257.102.
During the Legacy Rulemaking, EPA received public comment arguing
that state programs had become significantly more robust over the past
couple of decades, especially, since 2015 when EPA last conducted a
review of state programs. For example, Duke Energy provided information
on North Carolina's CCR program. The utility claimed that there are no
gaps within the state program including with respect to legacy surface
impoundments. Duke Energy further stated that the state's groundwater
rules establish robust groundwater monitoring and corrective action
programs. The company went on to describe aspects of the state's
program that, it argues, as applied to

[[Page 18984]]

two of its facilities, (i.e., the Riverbend and Cape Fear facilities),
results in stringent oversight by North Carolina Department of
Environmental Quality (NCDEQ).
Specifically, Duke Energy notes that with respect to Riverbend, the
state's Coal Ash Management Act (CAMA) prescribed the closure method
(i.e., closure by removal), Sess. L. 2014-122, Sec. Sec. 3.(b)(2),
(c)(1), (2), and mandated that impacted groundwater be restored in
accordance with the act's groundwater assessment and corrective action
provisions. As for Cape Fear, the utility notes that CAMA required
closure plans for all the company's impoundments not already subject to
closure by removal under the legislation, including the basins at Cape
Fear. N.C.G.S. Sec. 130A-309-214(a)(4). The utility proceeded to
describe many aspects of the program suggesting that the closure plans
are comprehensive and subject to significant regulatory oversight and
public participation. The key assertions are as follows:
<bullet> The closure plans, among other things, require the results
of a hydrogeologic, geologic, and geotechnical investigation of the
site; the results of groundwater modeling of the site; a description of
the provisions for disposal of wastewater and management of stormwater;
a description of the provisions for the final disposition of the CCR;
and a description of the plan for post-closure monitoring and care for
an impoundment for a minimum of 30 years.
<bullet> The closure plan approval process includes public
participation components involving public notice and comment and public
meeting(s) in county(ies) in which the site is located. After an
opportunity for public comment, NCDEQ makes the final determination as
to the protectiveness and adequacy of the closure plan.
The utility goes on to state that NCDEQ's Coal Combustion Residuals
Surface Impoundment Closure Guidelines for Protection of Groundwater
also sets out robust requirements to establish conformance with the
state's closure-by-removal performance standards. Duke Energy notes
that the guidelines establish clean-up levels commensurate with site-
specific background concentrations. For soil, the clean-up level is
either the site-specific background concentration or the lowest soil
screening level protective of groundwater. To develop soil remediation
goals and corresponding clean-up levels, facility owners or operators
must develop an excavation soil sampling plan for each site and submit
it to NCDEQ for a determination of whether the plan is sufficient in
scope to meet the performance standards for closure. Determinations
that CCR removal is complete, according to Duke Energy, rely on a
visual confirmation that all CCR and commingled CCR and soil have been
removed based on sampling of the material and analysis under polarized
light microscopy utilizing American Standards for Testing and Measures
D2488, Standard Practice for Description and Identification of Soils
(Visual--Manual Procedure).
EPA's independent examination of state CCR programs applicable to
legacy units did find that North Carolina's Coal Ash Management Act
(CAMA) requires closure of all unlined impoundments, including those at
inactive facilities that would qualify as legacy CCR surface
impoundments. Further, review of publicly available documentation from
Duke Energy, the owner of all currently identified legacy CCR surface
impoundments in the state, indicates the presence of state orders-on-
consent requiring corrective action for these units. All potential
legacy CCR surface impoundments in North Carolina have been or are in
the process of closure.
Since publication, several owners and operators of CCR units have
provided EPA with additional information they believe demonstrates the
adequacy of CCR unit closures performed under the oversight of other
regulatory authorities (e.g., state programs). For example, according
to Vistra Corp, the Illinois EPA (IEPA) oversaw the closure of a former
CCR surface impoundment at the shuttered Havana Power plant. The unit
was dewatered and closed in December 1993, under a corrective action
plan overseen by IEPA. Surficial water was removed and a three-foot
thick cover of soil with vegetation was installed. Groundwater data
provided by the utility showed a reduction of boron concentration and
compliance with the groundwater standards. At the former Hennepin Power
plant in Illinois, another legacy surface impoundment was closed under
IEPA oversight. According to Vistra Corp, surficial water was removed,
and the unit has been subject to groundwater sampling since 1996.
Initial sampling demonstrated exceedances of the boron groundwater
standard. In 2020, a final cover system was installed pursuant to the
federal CCR rule, consisting of a compacted soil barrier layer with a
minimum of 24 inches of earthen material with a maximum permeability of
1 x 10-7 centimeters per second. The utility states that in
limited areas, CCR may be saturated with groundwater during higher
flood events of the Illinois River. Vistra Corp contends that the
groundwater data demonstrates that simply dewatering and taking this
unit offline resulted in significant decreasing trends in boron since
1996, with several wells achieving compliance with the groundwater
standard for boron well before the cover system was installed. Further,
the utility suggests that the modeling conducted demonstrates that
boron concentrations are expected to continue the downward trend even
though some ash is saturated with groundwater.
Another utility, Tennessee Valley Authority (TVA), provided EPA
with information about Tennessee's CCR program. TVA explained that this
information suggests that site-specific human health and ecological
risk assessments conducted in the program follow EPA protocols.
According to the information provided, the risk assessments have found
that there are no unacceptable risks related to CCR management
identified for all receptors at most sites. Additionally, the utility
stated that potential risk to future workers, where identified, would
be mitigated by health and safety protocols. TVA explained that the
information provided also speaks to how the state handles closure and
corrective action. The state's closure decisions factor in ongoing
operations, planned extraction of CCR for beneficial use, risk
assessment results, qualitative impacts, and stability assessments.
Tennessee's corrective action program incorporates risk assessment
results and statistical evaluation of groundwater sampling data to
assess regulatory requirements. TVA further explained that no
corrective actions have been identified to address unacceptable risks,
but localized groundwater corrective actions are required at some units
to meet the groundwater protection standards.
The utility also provided specifics about the Tennessee-approved
closures at the former John Sevier Fossil Plant. TVA stated that the
information speaks to how the state closure and corrective action
requirements will control and minimize infiltration, reduce flux from
pore water and achieve compliance with groundwater protection
standards. Post-closure care requirements are intended to maintain
these conditions and the controls in place. The utility contended that
the cumulative result is that there will be no unacceptable risks to
offsite human or ecological receptors at the facility.
In a third example of relevant information provided to EPA since
promulgation of the Legacy Final Rule, Xcel Energy shared details of a

[[Page 18985]]

previously conducted closure under the authority of the state of
Minnesota. At the Black Dog Plant, the coal-fired generating units
ceased operating in April 2015 and disposal of CCR in the onsite units
ceased prior to October 19, 2015. The units were certified closed in
February 2017. The utility contends that this is an example of a site
that was successfully remediated under a rigorous state program and
meets acceptable risk criteria. Xcel Energy further states that the
quantities of CCR that remain onsite were subject to an extensive site
evaluation, risk assessment and the implementation of state-approved
remedial action that supported the conclusion that the site is not
adversely impacting human health or the environment.
The utility provided documentation of the closure and the state's
oversight including the risk assessment conducted, the state-approved
remedial action plan, state-approved long-term monitoring plan, and the
closure certification. The documentation provided suggests that, in
total, the closure involved the removal of 117,300 cubic yards of CCR
and impacted soils and the import of 717,000 cubic yards of clean fill
material. At the ponds where removal of all non-native materials
(including CCR) wasn't conducted, a 4-foot cap of clean imported fill
material was utilized. Additionally, groundwater monitoring was
conducted before and after the remedial action. The site now features a
bike path along the Minnesota River.
EPA intends to maintain the general procedures in the existing
regulations, whereby owners and operators of legacy surface
impoundments may defer compliance with the CCR unit closure standards
until a site-specific decision is made by the permit authority on the
equivalence of the previously conducted closures. However, based on the
information above as well as the considerations discussed in Unit
III.D. regarding the benefit of regulatory oversight (i.e., allowing a
permit authority to evaluate risk and determine requirements based on
site-specific considerations), the new tools provided to EPA as part of
the WIIN Act, and the ability of EPA to allow for non-uniformity in
attainment of the baseline RCRA standard of protection, EPA is
proposing to modify Sec. 257.101(g) to expand the deferral criteria.
Specifically, EPA proposes to adjust the deferral criteria by removing
three of the standards that currently must be met to be eligible for
the deferral. EPA is proposing to remove: (1) The detailed technical
requirements for a groundwater monitoring system, (2) The requirement
that a facility document that the legacy CCR surface impoundment
currently meets either the location standard in Sec. 257.60 or the
dewatering standard in Sec. 257.102(d)(1)(i), and (3) The requirement
that the regulatory authority conducted a site-specific risk
assessment. EPA is instead proposing that the owner or operator would
need to document that a regulatory authority played an active role in
overseeing and approving the closure and any necessary corrective
action, pursuant to an enforceable requirement issued on or after
October 19, 2015, a groundwater monitoring system was installed, and
groundwater monitoring was performed. The owner or operator would need
to also provide the same certification as to the veracity of the
documentation currently required under Sec. 257.101(g)(5).
EPA anticipates that this amendment will lead to an increase in the
number of closed legacy impoundments eligible for deferral. As a
result, fewer legacy surface impoundments will be required to undertake
additional closure activities before the CCR permit authority
determines that such actions are indeed necessary. It is worth noting
that all legacy surface impoundments eligible for the deferral would
still, at the time of permitting, be required to submit a permit
application with sufficient information, including groundwater data, to
demonstrate the applicable closure standards had been met. In the
meantime, the unit would be subject to groundwater monitoring and
corrective action in the event any problems are identified that require
remedial action. The CCR permit authority would then make a final
determination as to whether the previously conducted closure achieved
the applicable performance standards established in the Federal CCR
regulations.
The proposed amendment ensures that previous decisions made by
state or federal regulators remain unaffected until the CCR permitting
program can conduct site-specific evaluations. This approach allows for
greater continuity in the short term and ensures EPA does not require
compliance with additional subtitle D requirements that may not result
in benefits to human health or the environment unless and until it is
determined that additional closure activities are indeed necessary.
Furthermore, this change allows for greater implementation resources to
be directed to site-specific permitting to address risks and away from
evaluating compliance with a more complex set of deferral criteria.
Finally, adding this flexibility comes with relatively little tradeoff.
Most of these legacy CCR surface impoundments have been in place for
decades. More recently, these units were closed under the oversight of
a regulatory authority and now have controls in place to reduce risk.
Delaying potential compliance with the federal closure requirement for
a comparatively short period of time until a site-specific examination
of the units and their completed closure can be completed by a permit
authority is unlikely to significantly change the environmental
conditions or risks at these facilities. The risk associated with the
deferral is further attenuated by the ongoing requirement for
groundwater monitoring and corrective action. While the units were
already closed once under the oversight of a state or other authority
and so environmental controls may be in place, if the unit contaminates
groundwater, the groundwater monitoring system would identify it. The
corrective action requirements would then require remediation to ensure
no adverse effects to health and the environment.
At the time of permitting, the permitting authority would evaluate
the unit more closely--with the benefit of site-specific information--
to determine the ``equivalence'' of closure conducted under the state
or alternate authority. EPA is not proposing to revise this process
established under Sec. 257.101(g)(6). At this stage, additional
closure and/or post-closure requirements may be imposed by the
permitting authority to achieve compliance with the Part 257
regulations including the closure performance standard. As such, the
unit will ultimately achieve compliance with the Federal closure
performance standard--just under the oversight of a permitting
authority, rather than under a self-implementing framework.
Therefore, EPA is proposing that owners or operators of legacy CCR
surface impoundments that have completed a closure prior to November 8,
2024, where a regulatory authority played an active role in overseeing
and approving the closure and any necessary corrective action, pursuant
to an enforceable requirement issued on or after October 19, 2015; a
groundwater monitoring system has been installed; and groundwater
monitoring has been performed would be eligible to defer compliance
with the applicable closure performance standard until permitting. The
owner or operator would need to document they meet the criteria in an
owner-or-operator certified report. EPA is proposing to require this
documentation be completed within six months of the effective date of
the rule,

[[Page 18986]]

if finalized. This compliance timeframe was used for the original
deferral certification at Sec. 257.101(g). EPA expects this will
provide ample time for the owners and operators to prepare the
necessary documentation.
Solicitation of comment. EPA is also soliciting comments on an
alternative to this proposal that would allow owners and operators of
legacy surface impoundments to defer compliance with the closure
performance standard until the CCR permit authority can make a site-
specific determination regarding the 'equivalence' of the previously
conducted closure. Specifically, EPA is soliciting comment on potential
changes to Sec. 257.101(g) to expand the deferral criteria for legacy
CCR surface impoundments to owners and operators that completed closure
of the unit under state or federal regulatory authority prior to
November 8, 2024, where a regulatory authority played an active role in
overseeing and approving the closure and any necessary corrective
action, pursuant to an enforceable requirement issued on or after
October 19, 2015. In this alternative, installation and operation of a
groundwater monitoring system would not be required for an owner or
operator to avail themselves of the deferral. This alternative approach
would solely require that the owner or operator document that the
closure of the unit, and any necessary corrective action, was actively
overseen by a regulatory authority to qualify for the deferral.
However, under this alternative, the same information as required under
the proposed option would be required at the time of permitting.
EPA expects this option would allow a greater number of additional
units to qualify for the deferral than the proposed approach. Similar
to the proposed approach, all units for which closure decisions were
deferred to permitting, would be required to comply with the
groundwater monitoring, corrective action, and any applicable post-
closure requirements at least until a permit authority permits the
unit. The advantages of this alternative approach are the same as for
the proposed approach but would likely be realized at a greater number
of units. Much like the proposed approach, this alternative approach
would ensure that previous decisions made by State or Federal
regulators remain unaffected until the CCR permitting program can
conduct site-specific evaluations. This alternative approach would also
allow for greater continuity in the short term and would ensure EPA
does not require compliance with additional subtitle D requirements
that may not result in benefits to human health or the environment
unless and until it is determined that additional closure activities
are indeed necessary.
The disadvantage of this approach, relative to the proposed
approach, is that it may result in delays and a greater burden on the
CCR permit authority to determine the protectiveness of the completed
closure without historic groundwater monitoring data for the units in
question. Additionally, deferring compliance with the existing closure
performance standards at a greater number of units until permitting,
may result in a greater potential for adverse effects on human health
or the environment in the interim at a greater number of facilities.
Those potential impacts may be exacerbated by delays in permitting if
more closure ``equivalency'' determinations are deferred to permitting
and there isn't sufficient groundwater monitoring data to evaluate the
protectiveness of the completed closures in a timely manner.
However, as noted and described above, EPA received information
during the Legacy Rule development and since finalization from
utilities and trade groups arguing that CCR unit closures performed
under the oversight of other regulatory authorities (e.g., state
programs) are adequate. This information includes several examples of
unit specific closures with oversight from state or other regulatory
programs. Additionally, the descriptions of the regulatory programs
provided to EPA note that risk assessments were conducted, the
regulatory authorities conducted a variety of oversight activities, and
groundwater monitoring and corrective action were required to help
ensure the closures remain protective. Moreover, it's worth noting that
these units would still be subject to the groundwater monitoring,
closure and any necessary corrective action and post-closure care
requirements. See Sec. 257.100(f). As such, EPA is taking comment on
this alternative approach and, if supported by sufficient factual
comments, may finalize this approach.
If EPA were to finalize this approach, EPA would amend the criteria
for deferral in Sec. 257.101(g) to consist only of documentation that
a regulatory authority played an active role in overseeing and
approving the closure and any necessary corrective action, pursuant to
an enforceable requirement, and the certification as to the veracity of
the information. Specifically, EPA would remove the existing criteria
in Sec. 257.101(g)(2) through (4). The process for the CCR permitting
program to make the ``equivalence'' determination or establish
additional requirements for the legacy impoundment would remain
unchanged.
Additionally, due to the practical limitations and inherent
uncertainty related to the record, EPA requests comment on the adequacy
of the record for the proposal and the alternative option upon which
EPA is soliciting comment and, to the extent any gaps are identified,
requests suggestions for sources of additional information. As
described above, during the rulemaking for the Legacy Rule, the Agency
had received information to demonstrate that previous closure decisions
made under state or other regulatory authorities will protect human
health and the environment. Since promulgation of the Legacy Final
Rule, the Agency received additional information describing a handful
of state programs and several individual, site-specific closure
decisions. In acknowledgement of the additional information received,
and to realize the benefits described above, this proposal offers
greater deference to the state and other regulatory authorities that
made these closure decisions previously. EPA expects that those
authorities would not have approved of closures that presented a
reasonable probability of adverse effects to human health and the
environment.
However, the Agency lacks a record that unequivocally demonstrates
that all closure decisions made by other regulatory programs will be
similarly protective--in the near term--as applying the Federal CCR
closure requirements immediately. Such a record would consist of a
detailed review of all state CCR programs as well as other relevant
regulatory programs that may have overseen legacy CCR unit closures.
This review would need to provide a detailed understanding of the
programs at the points in time the relevant closure decisions had been
made. At present, EPA has information on a handful of state programs
and several site-specific closure decisions. While meaningful, this
information doesn't speak to every previous closure decision that had
been made. For example, even for closures conducted under voluntary
programs, the level of oversight of those programs may vary between
states. In some states, the voluntary closure may entail significant
oversight, (e.g., regulator review and approval of the closure and
groundwater monitoring plans, review of groundwater monitoring data)
but not necessarily in all states. EPA will consider such information
submitted as it develops the final action.

[[Page 18987]]

3. CCR Management Units
In the Legacy Final Rule, EPA established requirements to address
the risks from exempt solid waste management that involves the direct
placement of CCR on the land. EPA extended a subset of the existing
requirements in 40 CFR part 257, subpart D to these units, which are
CCR surface impoundments and landfills that closed prior to the
effective date of the 2015 CCR Rule, inactive CCR landfills, and other
areas where CCR is managed directly on the land. These additional
requirements apply to all active CCR facilities, all inactive
facilities with legacy CCR surface impoundments, and those active
facilities (i.e., facilities producing electricity for the grid as of
October 19, 2015) that ceased placing CCR in onsite CCR units prior to
the effective date of the 2015 CCR Rule (``other active facilities'').
In the preamble to the Legacy Final Rule, EPA discussed the
rationale of the definition of ``CCR management unit'' and the scope of
what would be considered a CCRMU under the final rule. See 89 FR 39044-
39051. EPA finalized this definition based on damage cases, the 2024
risk assessment, and comments received on the Legacy Proposed Rule.
Many of the Legacy Proposed Rule comments argued that the definition of
CCRMU is overly broad and treats many different disposal areas as a
worse-case scenario. Commenters further stated that the scope of the
CCRMU universe ignores the risk profiles of different historic disposal
areas and forces actions not tailored to the specific units. The
comments also said a one-size-fits-all approach to CCRMU does not make
sense given the widely variable risk profiles within this newly defined
category of regulated units.
In 2025, EPA received several letters from the regulated community,
including a coalition of regulated entities,\15\ USWAG,\16\ National
Rural Electric Cooperative Association (NRECA),\17\ Cross-Cutting
Issues Group (CCIG),\18\ Edison Electric Institute (EEI),\19\ American
Electric Power (AEP),\20\ PacifiCorp,\21\ Talen Energy via the National
Energy Dominance Council,\22\ and others that recommended changes to
the CCRMU requirements. The letters suggested these changes were
supported by several critiques of the Legacy Final Rule and the 2024
Risk Assessment, and recent Executive Orders, including
``Reinvigorating America's Beautiful Clean Coal Industry and Amending
Executive Order 14241'' (April 8, 2025).
---------------------------------------------------------------------------

\15\ Duke Energy et al 2025. Letter co-signed by Duke Energy,
Vistra Corp, Lower Colorado River Authority, City Utilities of
Springfield, Southern Illinois Power Cooperative, Gavin Power, Talen
Energy, Basin Electric Power Cooperative, Ohio Valley Electric
Corporation, Indiana-Kentucky Electric Corporation, and Louisville
Gas and Electric Company-Kentucky Utilities Energy to Lee Zeldin,
EPA Administrator. RE: Coal Combustion Residuals Rules Impede U.S.
Energy Production. January.
\16\ USWAG 2025a. Letter from Daniel L. Chartier, Executive
Director, Utility Solid Waste Activities Group to Lee Zeldin, EPA
Administrator. Re: Actions for Regulations for CCR. January.
\17\ NRECA 2025. Letter from Jim Matheson, Chief Executive
Officer, National Rural Electric Cooperative Association to Lee
Zeldin, EPA Administrator. January.
\18\ CCIG 2025. White paper reflecting Recommendations Updating
the Federal CCR Regulations. Cross-Cutting Issues Group. June.
\19\ EEI 2025a. Comments on Site-Specific Closure Alternative
Performance Standard. Edison Electric Institute. June.
\20\ AEP 2025. Meeting handout to EPA's Office of Land and
Emergency Management. American Electric Power. RE: Legacy CCR Rule
Reform Regulations. June.
\21\ PacifiCorp 2025. Letter from James Owen, Vice President of
Environmental and Energy Resources, PacifiCorp to EPA Region 8. RE:
PacifiCorp Priorities in EPA Region 8 States. April.
\22\ NEDC 2025. Comments from NEDC with CCR Reform Guiding
Principles. National Energy Dominance Council. August.
---------------------------------------------------------------------------

In many letters, the authors recommended rescinding the CCRMU
provisions. In other letters, regulated entities recommend that EPA
narrow the scope of CCRMU provisions and clarify certain requirements.
Some commenters recommended that EPA: (1) Eliminate the requirement to
identify CCRMU containing less than 1,000 tons of CCR; (2) Increase the
CCRMU deferral threshold from 1,000 tons to an alternative quantity
associated with acceptable beneficial use or to risk-based criteria for
stability, groundwater, and dust; (3) Exempt past beneficial use
placements and critical infrastructure sites; (4) Exempt areas of CCR
accumulation regulated by State agencies, including units closed in
accordance with State programs; (5) Establish a baseline to identify
potential CCRMU (e.g., facilities operating after a certain date); (6)
Establish options to exempt areas listed in the Facility Evaluation
Report (FER) as a CCRMU if the CCR material is removed from that area
within a specified time period (e.g., an area is exempt if the CCR is
removed with one year of the FER Part 2 being published; and (7) Limit
the CCRMU definition to past placements that pose identified present
risks.
In response to the information presented in the above letters and
based on the limitations of a national risk assessment, including the
2024 Risk Assessment, as discussed in Unit III.D. of this preamble, EPA
is proposing to rescind all CCRMU requirements. In the alternative, EPA
is soliciting comments on several potential revisions to the existing
CCRMU regulations. Each of these potential revisions is intended to
address one or more of the issues discussed above. Although the
potential revisions are not intended to be mutually exclusive (i.e.,
EPA may adopt several of them in the final rule), a single revision may
address multiple issues. Consequently, it may not be necessary to adopt
all the potential revisions to address all the issues that have been
raised to the Agency. EPA therefore requests comment on whether all the
various revisions discussed in Unit IV.A.3.b. of this preamble are
necessary or useful. Commenters are encouraged to consider the combined
effect of individual revisions in developing their comments. EPA also
requests that, if commenters believe that individual alternatives would
address the same issue, they provide views on whether (and why) one
alternative is preferable.
Lastly, given that EPA may adopt one or more of the options
discussed in Unit IV.A.3.b. of this preamble, EPA solicits comments on
the appropriate scope of the FER given the commenter's preferred
option(s). As explained in Unit III.C. of this preamble, the FER Part 1
documents the thorough review of readily and reasonably available
records regarding where CCR was either routinely and systematically
placed on land, or where facility activities otherwise resulted in
measurable accumulations of CCR on land. The FER Part 2 documents the
conclusions of a physical evaluation of the facility to address any
data and information gaps identified in FER Part 1. Together, the FER
Parts 1 and 2 are intended to provide a complete picture of the
historic use, placement and the status of CCR at the facility,
ultimately identifying any CCRMU of 1 ton or greater onsite. The FER
Part 1 requirements regarding record review were based off EPA's
understanding of what documentation would potentially hold information
about historic placements that would meet the definition of CCRMU.
However, EPA acknowledges that if the scope of the CCRMU universe is
modified, the FER requirements, specifically with respect to review of
readily and reasonably available records regarding where CCR was either
routinely and systematically placed on land, or where facility
activities otherwise resulted in measurable accumulations of CCR on
land, may warrant modification too. Therefore, EPA solicits comment on
the

[[Page 18988]]

appropriate scope of the FER requirements as they are impacted by the
options described below.
a. Rescind All CCR Management Unit Requirements
In response to the letters and requests that EPA has received since
January 2025 and based on the limitations of a national risk
assessment, including the 2024 Risk Assessment, as described in Unit
III.D. of this preamble, EPA is reconsidering its decisions to regulate
CCRMU. As stated above in Units III.D. and IV.A.3. of this preamble,
EPA received questions about the risk assessment and other comments
after the publication of the Legacy Final Rule that said the definition
of CCRMU is overly broad.
Some of the information EPA received after publication of the 2024
Legacy Rule suggests that EPA should rescind the CCRMU requirements and
is intended to show the infeasibility of the CCRMU requirements. CCIG
provided specific examples of this infeasibility in their letter dated
June 6, 2025,\23\ including rail embankments or railroad roadbed
constructed with CCR components that would pose logistical challenges
for groundwater monitoring, CCR used as drainage layers above composite
liners, CCR used in embankments, CCR used to construct over 10 miles of
road at the facility, previously closed surface impoundments below
plant infrastructure, an active landfill on top of a previously closed
unit, CCRMU under a natural gas pipeline, CCR used as fill for the
construction of the facility that processes and encapsulates CCR for
beneficial use, and units that were near closure but would be
considered CCRMU. CCIG also said that requiring the removal and
replacement of the wide range of uses of CCR that fall under the broad
CCRMU definition, including those described above, will end up causing
cascading issues that potentially could impact reliability, force the
use of virgin resources, and impose burdensome, unnecessary costs on
energy companies and their customers. Therefore, based on the reasons
above CCIG recommended EPA rescind the CCRMU requirements. Other
commenters stated that rescinding the CCRMU provisions was justified as
the court in the 2018 USWAG decision only required regulation of legacy
CCR surface impoundment and not CCRMU. Many of these letters also state
that CCRMU should be ``eliminated'' because: (1) The record has not
been fully developed to support regulating CCRMU, and (2) Significant
compliance costs outweigh any potential benefits to address unproven
risks. Several of the entities also claim the CCRMU regulations impose
infeasible, impracticable, and overly burdensome requirements on energy
companies with significant costs that would eventually be placed on
consumers.
---------------------------------------------------------------------------

\23\ CCIG 2025. White paper reflecting Recommendations Updating
the Federal CCR Regulations. Cross-Cutting Issues Group. June.
---------------------------------------------------------------------------

Other letters stated that EPA's 2024 Risk Assessment does not
support the overly broad CCRMU definition or demonstrate that all CCRMU
pose a reasonable probability of adverse effects on health or the
environment. The letters noted that the national risk assessment was
based on high-end risks and did not accurate capture the variability of
risk posed by units at many facilities. The authors conclude that EPA's
Risk Assessments systematically overstate the risk from CCR disposal
units and fills, and that it would be more effective and appropriate to
assess risks on a site-specific basis. Furthermore, the commenters
state that EPA did not justify the CCRMU regulations through a proper
risk assessment.
As explained in Unit III.D. of this preamble, EPA uses a national
risk assessment for a particular source or industry category to inform
its decision concerning whether a regulatory program is needed or in
need of revisions. Both the 2014 and 2024 Risk Assessments were
designed to capture the full spectrum of potential disposal scenarios
across the country with available data and decisions about the need for
national regulations were based on high-end risks identified from
across these scenarios, considered together with proven damage cases,
to ensure that regulations would be consistently protective. The Agency
acknowledges that these high-end risks may not manifest at every site
and concurs that risks associated with individual CCR units may be
lower. This is equally true for disposal units, fills, piles, and
unencapsulated accumulations on the land for any other stated purpose.
In addition, EPA is proposing to find the current definition of
CCRMU is overly broad, capturing units that under this proposal would
not involve ``disposal.'' Specifically, EPA's proposed changes
affecting beneficial use and storage of CCR would result in the
existing definition of CCRMU encompassing some units that do not
involve ``disposal'' as defined Sec. 257.53. As explained in more
detail in Unit IV.C., EPA is proposing to revise the definition of
beneficial use to eliminate the distinction between on-site and off-
site activities, and to eliminate the definition of a CCR pile. If
those proposals are adopted, the current definition of a CCRMU as
``area of land on which any noncontainerized accumulation of CCR is
received, is placed, or is otherwise managed,'' would also capture CCR
storage units and beneficial use projects (other than roadbed and
associated embankments, which are explicitly excluded from the
definition) and consequently would not involve the disposal of CCR. See
definition of ``disposal'' in Sec. 257.53, which states ``For purposes
of this subpart, disposal does not include the storage or the
beneficial use of CCR.''
EPA acknowledges that this is a change in position from previous
statements in the 2024 CCR Legacy Rule, which stated that direct
placement of CCR on the land onsite of a utility, with nothing to
control releases is, by definition, a CCR pile and therefore not
beneficial use (while, in contrast, CCR that is beneficially used off-
site is not a CCR pile), and then further referenced statements from
the 2015 CCR Rule that CCR piles constitute disposal and are
consequently subject to all regulatory criteria applicable to CCR
landfills. (89 FR 39050).
However, as explained in more detail in Unit IV.C., EPA's proposed
revisions would ensure consistency and clarity across all settings in
accurately identifying which practices are beneficial use or storage,
and not disposal.
Finally, EPA finds that the existing definition of CCRMU runs afoul
of several recent executive orders: Executive Order 14154 ``Unleashing
American Energy,'' 90 FR 8343 (January 29, 2025); Executive Order 14156
``Declaring a National Energy Emergency,'' 90 FR 8433 (January 30,
2025); and Executive Order 14219 ``Ensuring Lawful Governance and
Implementing the President's `Department of Government Efficiency'
Deregulatory Initiative,'' 90 FR 10583 (February 25, 2025). EPA is
proposing to rescind the CCRMU provisions consistent with those
directives.
Therefore, based on the information above, along with the
conclusions stated in Unit III.D. of this preamble, EPA is proposing to
remove the CCRMU regulations from 40 CFR part 257, subpart D. In
particular, EPA is proposing to amend or remove the following
regulatory text sections, such that CCRMU are no longer units regulated
under 40 CFR part 257: Sec. Sec. 257.50(d); 257.53: definitions of
``CCR management unit'', portion of ``CCR unit'', ``Closed prior to
October 19, 2015'', ``Critical infrastructure'',

[[Page 18989]]

``Inactive CCR landfill'', and ``Regulated CCR unit''; 257.75;
257.90(b)(3); a sentence from 257.90(e); change 257.95(b) back to 2015
CCR Rule language; references to CCRMU in 257.100(h)(2); 257.101(f);
portions of 257.101(g); 257.101(h); title of 257.102;
257.102(b)(2)(iii) and (v) and renumber (iv) to (iii);
257.102(f)(1)(iii); 257.100(f)(2)(ii)(E) and (F), 257.104(d)(2)(iii);
257.105(f)(25) and (26); 257.106(f)(24) and (25); 257.107(f)(24) and
(25).
b. Alternative Approaches for Comment
As stated above, EPA is soliciting comment on several alternative
approaches to address the concerns laid out in Units III.D. and IV.A.3.
of this preamble regarding the CCRMU regulations. Specifically, EPA is
soliciting comment on: (1) Deferring all CCRMU requirements, other than
the requirement to complete the facility evaluation, to permitting; (2)
Establishing groundwater monitoring and corrective action zones for
CCRMU; (3) Exempting past onsite CCR uses that meet the definition of
beneficial use; (4) Expanding the roadbed exemption; (5) Expanding the
deferral criteria for certain CCRMU closures to permitting; (6)
Removing ``other active facilities'' from the regulated universe; and
(7) Developing a new threshold for CCRMU. EPA will consider comments on
the proposal and all these options before making a final decision. If
EPA elects to not rescind all regulation of CCRMU, EPA may select one
or several of the options to finalize. For example, EPA may choose to
only finalize the option to defer all CCRMU requirements aside from the
facility evaluation to permitting. Alternatively, EPA may choose to
finalize the options to defer all CCRMU requirements aside from the
facility evaluation to permitting, expand the roadbed exemption, and
exempt past onsite CCR uses that meet the definition of beneficial use.
If EPA were to finalize this combination of options, the result would
be a much smaller CCRMU universe consisting primarily of inactive
landfills and units closed prior to 2015, which would only be subject
to the facility evaluation requirements in Sec. 257.75 until such time
that the permit authority could evaluate these units. Since EPA is
soliciting comment on several other alternative approaches to amending
the scope of the CCRMU universe, EPA is not including these regulatory
changes in the proposed regulatory text in this rule, as it could cause
confusion for the reader. However, EPA will describe the regulatory
text changes these alternative approaches would have if finalized in
the preamble below. EPA requests comment on the proposed regulatory
text changes as well as these alternatives, as well as how EPA should
revise the FER requirements considering the alternatives below.
i. Deferral of CCR Management Unit Requirements To Permitting
EPA is taking comment on an alternative approach to addressing the
issues identified in Units III.D. and IV.A.3. of this preamble with the
existing CCRMU regulation. Under this alternative approach, owners or
operators of regulated CCR units would still be required to complete
the two-part FER to identify and delineate CCRMU at the facility.
However, the requirement to comply with the remaining CCRMU regulations
would be deferred until a CCR permit authority is able to evaluate the
risks posed by these units and determine which requirements are
appropriate for the CCRMU. Essentially, under this alternative
approach, all CCRMU would be treated the same as CCRMU containing
between 1 and 1,000 tons are treated under the existing regulations.
In the Legacy Final Rule, EPA finalized facility evaluation,
fugitive dust, groundwater monitoring, corrective action, closure, and
post-closure care requirements for CCRMU. As a result of the Legacy
Final Rule, owners or operators of regulated CCR units are required to
conduct a facility evaluation to identify and delineate any CCRMU
containing one ton (or more) at the facility and document the findings
in two reports. In addition, owners or operators of a regulated CCR
unit are required to ensure that all identified CCRMU containing 1,000
tons or more comply with the existing requirements in 40 CFR part 257,
subpart D for groundwater monitoring, corrective action (where
necessary), recordkeeping, notification, and internet posting and in
certain cases, closure, and post-closure care requirements. Regulation
of CCRMU between one and 1,000 tons is deferred until a subsequent
permit authority can assess the risks posed by these smaller CCRMU,
individually or in the aggregate, and determine which, if any,
requirements are appropriate for the CCRMU. In addition, the Legacy
Final Rule deferred the requirement to demonstrate compliance with
Sec. 257.102 for CCRMU that closed prior to the effective date of this
rule in accordance with alternative, substantially equivalent
requirements (Sec. 257.101(g)). EPA also deferred the requirement to
initiate closure where the CCRMU is located beneath critical
infrastructure, such as high power electric transmission towers, air
pollution control or wastewater treatment systems, or an electrical
substation, until whichever occurs first: (1) the infrastructure is no
longer needed, (2) a permit authority determines closure is necessary
to ensure that there is no reasonable probability of adverse effects on
human health or the environment, or (3) the closure or decommissioning
of the facility. See Sec. 257.101(h).
However, as described in greater detail above, since finalization
of the Legacy Rule, EPA has received many letters from regulated
entities suggesting: (1) The record has not been fully developed to
support regulating CCRMU, (2) Significant compliance costs outweigh any
potential benefits to address unproven risks, (3) CCRMU regulations
impose infeasible, impracticable, and overly burdensome requirements on
energy companies with significant costs that would eventually be placed
on consumers, and (4) the self-implementing structure is not
appropriate to address the variability in risk posed by the broad scope
of units regulated as CCRMU. As noted above, EPA is considering and
requesting comment on an alternative regulatory structure which would
help alleviate some of these concerns. Specifically, under this
alternative approach, owners and operators of covered facilities would
still be required to complete the two-part facility evaluation report
to identify and delineate CCRMU at the facility. However, the
application of additional CCR unit regulations would be deferred until
the CCR permit program assess the risks posed by the identified CCRMU,
individually or in the aggregate, and determine which, if any,
requirements are appropriate for the CCRMU.
This alternative approach would address these concerns by allowing
the CCR permit authority to make a site-specific, risk-based decision
as to what requirements are appropriate to apply to any given CCRMU
individually, or in aggregate, at a facility. Such an approach would
leverage the expertise and judgement of the CCR permit authority while
taking into account the variability in CCRMU and site-specific
considerations. Allowing for greater site-specific decision-making
would allow for risk-based decisions to result in potentially more
efficient outcomes that could avoid unexpected complications and issues
or require compliance with provisions that result in no benefit to
health or the environment. For example, CCIG claimed that the current
national standard requiring the removal and

[[Page 18990]]

replacement of the wide range of uses of CCR that fall under the CCRMU
definition will end up causing cascading issues that potentially could
impact reliability, force the use of virgin resources, and impose
burdensome, unnecessary costs on energy companies. Additionally, this
option would allow for impacts on infrastructure to be considered. For
example, there are examples were energy, waste, water, transportation
or other vital infrastructure have been built on top of previously
closed CCRMU. The Legacy Rule attempted to address this situation at
Sec. 257.101(h) by providing national criteria for deferring the
closure requirements for the CCRMU. However, this alternative option
would provide a permit authority greater flexibility and ability to
adapt regulatory requirements to the unique needs of the situation.
Notably, this alternative approach would extend a permit writers'
flexibility beyond just the closure requirements, allowing permit
writers to adjust, within the standards set forth in the revised rule,
the regulatory requirements in part 257 (e.g., more appropriate
groundwater monitoring requirements could be developed) on a case-by-
case basis to account for individual site conditions. Since most of
these CCRMU have been in place for decades, delaying potential
compliance with the federal requirements for a comparatively short time
until a permit authority evaluates these units is unlikely to
dramatically change the environmental conditions or risks at these
facilities.
Such an approach could still pose no reasonable risk of adverse
effects to health or the environment. State permitting and waste
programs have a comparatively long history of implementing state
requirements at CCR units including CCRMU. EPA has received a
substantial amount of information regarding CCR oversight and
regulation by state programs to demonstrate that site-specific
decisions made by these authorities are protective. See Units IV.A.2.
and IV.B.2.a. of this preamble. This includes, in some instances,
examples of state oversight of cleanups or closures of CCRMU.
For example, TVA provided EPA with information about Tennessee's
CCR program. This information suggests that site-specific human health
and ecological risk assessments conducted in the program follow EPA
protocols. According to the information provided, the risk assessments
have found that there are no unacceptable risks related to CCR
management identified for all receptors at most sites across the TVA's
portfolio. Additionally, potential risk to future workers, where
identified, would be mitigated by health and safety protocols. The
information provided also speaks to how the state handles closure and
corrective action. The state's closure decisions factor in ongoing
operations, planned extraction of CCR for beneficial use, risk
assessment results, qualitative impacts, and stability assessments.
Tennessee's corrective action program, meanwhile, incorporates risk
assessment results and statistical evaluation of groundwater sampling
data to assess regulatory requirements. The utility explains that no
corrective actions have been identified to address unacceptable risks,
but localized groundwater corrective actions are required at some units
to meet the groundwater protection standards.
Talen Energy provided information pointing out that states, such as
Pennsylvania, have had Residual Waste regulations that have been used
to address CCR for decades. State-level Dam Safety regulations also
exist and apply to certain CCR units. The utility stated that these
regulations and associated oversight ensure the safe and
environmentally-acceptable closure of CCR units. Talen Energy argued
that the federal CCR program needs a better mechanism to recognize
prior state approvals and regulatory requirements which may be
equivalent or as protective as the federal CCR requirements.
Additionally, during the Legacy Rulemaking, EPA received public
comments arguing that state programs had become significantly more
robust over the past couple of decades and, specifically, since 2015
when EPA last conducted a review of state programs. For example, Duke
Energy provided information on North Carolina's CCR program. The
utility claims that there are no gaps within the state program and that
the state's groundwater rules establish robust groundwater monitoring
and corrective action programs. Duke Energy proceeded to describe
aspects of the program's closure requirements suggesting that the
closure plans are comprehensive and subject to significant regulatory
oversight and public participation. The key assertions are as follows:
<bullet> The closure plans, among other things, require the results
of a hydrogeologic, geologic, and geotechnical investigation of the
site; the results of groundwater modeling of the site; a description of
the provisions for disposal of wastewater and management of stormwater;
a description of the provisions for the final disposition of the CCR;
and a description of the plan for post-closure monitoring and care for
an impoundment for a minimum of 30 years.
<bullet> The closure plan approval process includes public
participation component involving public notice and comment and public
meeting(s) in county(ies) in which the site is located. After an
opportunity for public comment, NCDEQ makes the final determination as
to the protectiveness and adequacy of the closure plan.
Moreover, Duke Energy provided several examples of CCRMU for which
North Carolina has required closure activities through existing state
authorities. Here is a description of the way in which North Carolina
assessed and addressed CCRMU according to the information provided.
First, in 2017, the state required the utility to assess and remediate
or close what the state called ``primary sources'' and ``secondary
sources''--not just the CCR surface impoundments--across 14 coal ash
facilities in the state. These ``primary sources'' and ``secondary
sources'' appear to meet the definition of CCRMU had EPA defined that
concept in 2017 and would also capture contamination from CCRMU. In
response, the utility developed a staged plan to address these CCRMU.
The first stage involves CCRMU located near CCR surface impoundments so
if there were any soil and groundwater contamination from the CCRMU,
the impacts would be addressed along with the CCR surface impoundments.
The second group involves CCRMU located where a groundwater divide or
surface water area separate these potential primary sources from the
CCR surface impoundments. These CCRMU were investigated independent of
CCR surface impoundments, and assessment and corrective action is
subject to a separate and distinct plan from the surface impoundments.
The state later required Duke Energy to prepare updated comprehensive
site assessments and updated corrective action plans to address the
CCRMU identified by the utility in response to the 2017 request.
In total the utility identified 25 CCRMU. Based on the information
provided, seven have already been fully excavated, six have excavation
in progress, four are planned to be excavated, four have been closed
and capped with a synthetic cover, two are in the process of being
closed with a synthetic cover, and two are undergoing further
investigation by NCDEQ. Duke Energy concluded that no CCRMU are being
ignored, and the foregoing demonstrates that the actions being
undertaken pursuant to strict state

[[Page 18991]]

oversight are sufficiently protective to not pose a reasonable
probability of adverse effects to health or the environment.
Other commenters presented individual examples of CCRMU that had
been closed in accordance with State requirements, which the commenters
believed would demonstrate the State closures were equally as
protective as those conducted in accordance with Sec. 257.102. These
included the following examples:
<bullet> A facility has an approximately 20-acre dry stack landfill
with 20 plus years of groundwater monitoring that does not show
groundwater exceedances, zero potential receptors downstream (from the
direction of groundwater) that use wells for drinking water (also no
potable wells within a two-mile radius). The landfill construction
using best practices to minimize erosion potential, including only
placement of stabilized material in the landfill, perimeter ditch
surrounding the entire landfill to collect any runoff that is processed
before discharge, and the unit is regulated by the Florida Department
of Environmental Protection that includes semi-annual groundwater
monitoring results review and yearly onsite regulatory inspections.
<bullet> Another facility had two CCRMU landfills that were closed
prior to the effective date of the 2015 CCR Rule and were closed in
accordance with the State of Florida's Chapter 62-701, F.A.C., for
municipal and solid waste landfills. Neither landfill was built on top
of a liner system. The closed landfills were subject to design criteria
for cover systems and stormwater management, as well as long-term
operations and maintenance provisions. The groundwater monitoring
system requirements for landfills in Florida are similar to, but not
the same as, those in the 2015 CCR rule. Both closed cells would be
subject to corrective action if dictated by the monitoring program.
Maintenance, inspections, and repair of the cover systems, as needed,
are also part of the long-term care program.
<bullet> Another facility reported closing an inactive CCR landfill
in the 1980s. The 20-acre site was used to dispose of bottom and fly
ash, including scrubber sludge. The owner performed monitoring of a
nearby spring to demonstrate whether any ponded water was leaking. Upon
visual inspection, it was determined that the bentonite/clay-lined pond
remained intact throughout the active operation of the landfill.
However, because of the age of the site, groundwater monitoring wells
were not required.
Since the finalization of the Legacy Rule, EPA also received a
survey of a select set of state risk-based regulatory programs. This
survey compared the components of some of these programs to CERCLA and
RCRA Subtitle C and states that the risk-based programs are based on
scientific principles supporting regulatory consistency, scientific
integrity, and practical implementation. Additionally, the survey
provided some additional information on certain state program examples
which, the survey concludes, demonstrate their regulatory efficiency
and effectiveness. The survey cited the Texas Risk Reduction Program,
Colorado Voluntary Cleanup and Redevelopment Program, Michigan Part 201
Cleanup Program, Virginia Voluntary Remediation Program, Massachusetts
Contingency Plan Waste Site Cleanup Program.\24\
---------------------------------------------------------------------------

\24\ The regulations already contain two pathways for legacy
impoundments to certify closure by removal (i.e., Sec.
257.100(g)(1)-(6) for those with available groundwater data and
Sec. 257.100(h) for those units that needed to conduct additional
groundwater monitoring). These two paths are unchanged by this
proposal. The third, proposed, avenue for certification of closure
by removal is an additional avenue not intended to disrupt,
supersede, or otherwise alter the two existing avenues.
Haley Aldrich. Report on Joint Data Analysis to Support
Revisions to Federal Regulation of Coal Combustion Residuals.
September 2025.
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As noted above in Unit III.D., the 2024 Risk Assessment is a
national risk assessment and not representative of risk posed by all
CCR units at all facilities. Additionally, as described in Unit III.D.
of this preamble, EPA has the ability to rely on permit authority's
oversight to tailor the CCR requirements and provide greater
flexibility to owners or operators while ensuring there is no
reasonable probability of adverse effects on health or the environment
from the regulated units. Deferring the application of most of the
CCRMU requirements to the CCR permitting program would allow for a
greater understanding of the risk posed by these units and could result
in more appropriate, tailored regulatory requirements being applied to
the units. Moreover, the issuance of a CCR permit will involve public
comment and are final actions that could be challenged
administratively, and in federal or state court. In consideration of
the information above and in Unit IV.A.2. of this preamble regarding
state programs and the potential advantages of deferring application of
most of the CCRMU requirements to the CCR permitting program, EPA is
soliciting comment on this option.
After a review of submitted comments, EPA will determine if there
is sufficient support to finalize this approach in its final action. If
EPA were to finalize such an approach, EPA would amend Sec. 257.50(d)
to read: CCR management units located at active facilities or
facilities with a legacy CCR surface impoundment are subject only to
the requirements of the facility evaluation report in Sec. 257.75
until a permit authority determines that regulation of these units,
either individually or in the aggregate, is warranted and determines
the applicable requirements. EPA would, accordingly, also rescind
Sec. Sec. 257.90(b)(3), 257.100(h)(v) through (ix), 257.101(f) and
(h), 257.102(b)(2)(iii) and (v), 257.102(f)(1)(iii),
57.102(f)(2)(ii)(E) and (F), and 257.104(d)(2)(iii). EPA would also
remove reference to CCRMU from Sec. 257.101(g).
In addition to the alternative above and for the same reasons in
Unit IV.A.2.b., EPA requests comment on the adequacy of the record for
the alternative option upon which EPA is soliciting comment and, to the
extent any gaps are identified, requests suggestions for sources of
additional information. As several regulated entities have raised
concerns with scope of the search required for information concerning
historical CCR placement (e.g., interviews of former employees, files
in digital formats no longer supported), EPA is also seeking comment on
whether the scope of the effort required to search for information
concerning the location of CCRMU needs clarification.
ii. Establishing Groundwater Monitoring and Corrective Action Zones for
CCRMU
EPA is soliciting comment on an option to establish the equivalent
of a hazardous waste facility's ``area(s) of concern'' or ``solid waste
management area(s)'' for facilities with CCRMU for compliance with
groundwater monitoring and corrective action. Specifically, this would
allow owners or operators of CCRMU to establish a CCRMU groundwater
monitoring and corrective action zone that contains multiple CCRMU and
would be monitored by a single groundwater monitoring system.
The existing regulations allow owners or operators of CCR units to
monitor groundwater at multiple units with a single groundwater
monitoring system (i.e., a multiunit groundwater monitoring system). 40
CFR 257.91(d). A multiunit groundwater monitoring system must be
equally capable of

[[Page 18992]]

detecting background and groundwater contamination at the waste
boundary as an individual monitoring system. The regulation further
specifies that this determination must be based on the consideration of
several factors, including the number, spacing, and orientation of the
CCR units, the hydrogeologic setting, the site history and the
engineering design of the CCR units. A qualified professional engineer
must certify this demonstration. Whether a single or multi-unit system
has been installed, the monitoring wells must be cased in a manner
maintaining the integrity of the borehole and must be maintained to
meet design specifications.
As discussed in the preamble to the Legacy Final Rule, the existing
groundwater monitoring and corrective action requirements are
essentially the same requirements that have been applied to both
hazardous waste and municipal solid waste disposal units for decades.
The preamble further states there is nothing about CCRMU that makes
them distinct enough to warrant separate groundwater monitoring
requirements from other CCR units. Therefore, EPA finalized the
requirement that owners or operators of CCRMU comply with the existing
groundwater monitoring and corrective action provisions in 40 CFR part
257.
However, since finalization of the 2024 Legacy Rule, members of the
regulated community have continued to express the need for alternative
groundwater monitoring requirements, such as expanded multiunit or
facility-wide groundwater monitoring. These utilities have pointed to
the difficulty of determining CCRMU boundaries and the prevalence of
CCRMU across the facility. Specifically, commenters have stated that
the widespread historic practice of placing non-containerized CCR
across a facility coupled with lack of historical documentation results
in uncertainty regarding the boundaries of CCRMU, even with the field
sampling required as part of the facility evaluation. Some companies
have expressed concern about finding CCRMU as a result of complying
with the groundwater monitoring and corrective action requirements
(e.g., while determining the source of potential contamination) or
through future development projects onsite (e.g., encountering CCR
while conducting earthwork for new infrastructure). Other utilities
have raised concerns regarding the appropriateness of the existing
groundwater monitoring requirements when the CCRMU being monitored is
miles long (e.g., a haul road or perimeter road) or quite numerous.
Furthermore, members of industry have expressed that the Agency should
allow facilities to adopt an area-wide or facility-wide groundwater
monitoring and corrective action approach where: (1) the facility has a
large number of CCRMU such that it is not practical to monitor and
clean-up each CCRMU individually, or (2) the facility demonstrates that
no contaminants are migrating offsite or otherwise causing off-site
impacts. The commenters stated that an area-wide or facility-wide
approach would allow facilities to address risk posed by CCRMU in a
more holistic way, where appropriate.
Based on this information, the EPA is now aware of instances where
the characteristics of the CCRMU, such as the size and shape (e.g.,
lengthy roads), or the prevalence (e.g., numerous CCRMU across the
facility) justify a different approach to groundwater monitoring.
Therefore, the Agency is soliciting comment on whether a more holistic
approach, often referred to as either ``area(s) of concern'' or ``solid
waste management area(s)''in hazardous waste facility permits or orders
would be appropriate to apply to CCRMU. Under this approach, owners or
operators of CCRMU would have greater flexibility to establish
groundwater monitoring networks around multiple CCRMU. This approach
would allow the owner or operator to designate an area of the facility
where multiple CCRMU are present as a ``CCRMU groundwater monitoring
and corrective action zone,'' essentially creating a single CCRMU for
the purposes of groundwater monitoring and corrective action. This
would allow a single groundwater monitoring system to be used in areas
where it is difficult to determine exactly where the CCRMU waste
boundaries are located, either due to historical CCR placements, the
sheer number of co-located or nearby disposal areas, or any gaps in
records related to past practices. As an example, if CCR was disposed
of in multiple locations throughout the facility in a manner that makes
it difficult to determine the precise waste boundaries of each CCRMU
for the purposes of groundwater monitoring, the owner or operator could
designate an area as a CCRMU groundwater monitoring and corrective
action zone and utilize a single groundwater system around that area.
In such cases, where CCRMU are located throughout the facility, the
owner or operator could decide to combine some or all CCRMU,
effectively creating a facility-wide groundwater monitoring network
that encompasses all the CCRMU at the facility. When designating CCRMU
groundwater monitoring and corrective action zones, the owner or
operator must ensure the groundwater monitoring system is capable of
readily detecting groundwater conditions in the uppermost aquifer that
are representative of any potential contamination from CCRMU within the
zone.
The Agency is requesting comment on the reasons owner or operators
consider the existing multiunit approach to be infeasible or otherwise
problematic to implement for CCRMU. Further, EPA is soliciting site-
specific examples of the need for combining CCRMU into CCRMU
groundwater monitoring and corrective action zones (i.e., the
equivalent of ``area(s) of concern'' or ``solid waste management
area'') for the purpose of groundwater monitoring. EPA specifically
requests examples where the owner or operator would need to combine
CCRMU across the facility into a single CCRMU groundwater monitoring
and corrective action zone, essentially creating a facility-wide
groundwater monitoring network. Lastly, the Agency is requesting
comment on whether this approach would be beneficial considering the
other options EPA is soliciting comment on for CCRMU and which, if any,
of the various other options under consideration that commenters
believe should be combined with this option to make compliance with the
groundwater monitoring regulations practically feasible.
iii. Exempt Past Onsite CCR Uses That Meet the Definition of Beneficial
Use
As discussed in Unit IV.C. of this preamble, EPA is proposing a new
definition of ``beneficial use'' at Sec. 257.53, which would eliminate
the fourth criterion, recognizing that the first three criteria in the
beneficial use definition provide a sufficient framework for
identifying when any placement of CCR on the land, whether encapsulated
or non-encapsulated, roadway or non-roadway, constitutes a beneficial
use rather than disposal for purposes of 40 CFR part 257. EPA also is
proposing that this definition apply equally to all CCR beneficial use
projects, whether conducted onsite at the generating utility or
offsite.
However, EPA notes that the revised definition of beneficial use
would not apply retroactively. Several stakeholders have raised the
issue of exempting past CCR uses at utilities that meets the definition
of ``beneficial use.'' Thus, EPA is requesting comment on including an
exemption from the definition of CCRMU for

[[Page 18993]]

unencapsulated CCR uses, regardless of when such use occurred, that
meet the definition of beneficial use, unless such a use is causing or
contributing to a statistically significant level above the groundwater
protection standard.
Such an exemption would encompass both the current and the proposed
expanded roadbed exemption and would also apply to non-roadway
beneficial uses of unencapsulated CCR, such as engineered structural
fill, both past and present, if they meet the first three criteria in
the beneficial use definition.
iv. Expand the Roadbed Exemption
Under the current regulations any CCR used in roadbed and
associated embankments is not considered to be a CCRMU. See definition
of ``CCR management unit'' at Sec. 257.53. As EPA explained in the
2015 CCR Rule preamble, the methods of application, including the
amounts and manner of CCR use, for roadbeds and associated embankments
are sufficiently different from CCR landfills that EPA cannot
extrapolate from the available risk information to determine whether
these activities present similar risks. Roadways (i.e., roadbed and
associated embankments) are subject to engineering specifications and
material requirements. For example, the engineering specifications for
roadbeds generally specify CCR to be placed in a thin layer (e.g., six
to 12 inches) under a road. The placement of CCR under the surface of
the road limits the degree to which rainwater can influence the
leaching of the CCR. There are also significant differences between the
way roadways and landfills can potentially impact groundwater, such as
the nature of mixing in the media and the leaching patterns. First, CCR
landfills can generally be represented as a homogenously mixed system.
By contrast, roadways are generally constructed of several layers with
different material properties (heterogeneity). This difference affects
the hydraulic conductivity of a mass of CCR in a landfill, as compared
to CCR placed in an embankment. Any potential leaching will tend to
spread over the length of the embankment, as opposed to the leaching in
a downward motion that would occur in a homogenously filled landfill.
Furthermore, the construction of roadways is supervised and approved by
State or Federal Department of Transportation (DOT) engineers who
ensure compliance with engineering specifications. Finally, EPA is
concerned that groundwater monitoring of a roadway may not be
practicable. See 80 FR 21353 and 89 FR 32018.
Even though EPA considers that the available information does not
demonstrate that use in roadway presents sufficient risk to warrant the
suite of requirements applicable to CCRMU, that conclusion changes in
the event the CCR in roadbed or associated embankments is contaminating
groundwater. Accordingly, if an owner or operator subsequently
determines that the CCR in onsite roadbed is contributing to
contamination to the aquifer, the owner or operator is required to
address the contamination. For example, if during an ongoing corrective
action, an owner or operator identifies the roadbed as an additional
source of contamination, it would be required to address that
contamination as part of the ongoing remediation of the aquifer.
Since 2025, EPA received letters requesting that EPA expand the
exemption of ``roadbed and associated embankments'' in the CCRMU
definition in Sec. 257.53 to interpret those terms to include all use
of CCR in construction of roads, railbeds, and embankments and similar
uses (unless, as is currently stated in the definition, ``the roadbed
is causing or contributing to a statistically significant level above
the groundwater protection standard''). See Merriam-Webster, Roadbed,
<a href="https://www.merriam-webster.com/dictionary/roadbed">https://www.merriam-webster.com/dictionary/roadbed</a> (last visited
September 17, 2025); general definition of ``roadbed'' includes ``the
bed on which the ties, rails, and ballast of a railroad rest.''
According to members of industry, these clarifications are consistent
not only with the regulatory text as currently drafted, but also RCRA
generally and policy goals to reduce disposal and waste footprints.
Certain letters sent to EPA also included site-specific examples of
CCR facilities with roadways or railbeds that would be impacted by the
CCRMU regulations.\25\ One letter described a utility with multiple
sites with over 10 miles of roads that are entirely constructed of ash
or blended with ash. Requiring the removal of such ash would
significantly disrupt facility operations. Another company reported
that regulation of roads creates a CCRMU that is 30 miles long.
According to the utility, groundwater monitoring and replacement of
existing embankments with other natural resources would be expensive,
complicated, time-consuming, and resource-intensive, and would also
risk contamination. Another utility stated that it potentially has an
unknown volume of CCR material along a railroad, but only a portion of
the railroad is within the facility boundary. Due to fencing, which
emphasizes the plant's boundary line and obscures access to the rest of
the railroad, it would be difficult not only to assess the presence of
CCR in the area but also access the area the plant does not own.
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\25\ CCIG 2025. White paper reflecting Recommendations Updating
the Federal CCR Regulations. Cross-Cutting Issues Group. June.
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EPA also received a request to clarify that the roadway or roadbed
and associated embankments exemption applies regardless of whether
there was oversight by a State agency and to extend the exclusion to
all embankments.
Based on this information, EPA is soliciting comment on whether to
expand the existing roadbed exemption in the definition of ``CCR
management unit'' at Sec. 257.53 to include roadbed, railbed, and all
roadbed embankments. Under this alternative, the use of CCR in roadbed,
railbed, and all roadbed embankments would be exempt from the CCRMU
regulations, unless they are causing or contributing to a statistically
significant level above the groundwater protection standard. As
discussed above, the inclusion of railbed fall in the plain language
meaning of the term ``roadbed'' as well. This exemption would apply
regardless of if there was oversight by a State agency of the
construction of the roadbed, railbed, and associated embankments. EPA
specifically requests comment on codifying a definition of ``roadbed''
to mean ``the foundation of a road prepared for surfacing or surface on
which or ties, rails, and ballast of a railroad rest''. EPA also
requests comment on codifying a definition of ``roadbed embankment'' to
mean ``material that is placed and compacted for the purpose of raising
the grade of a roadbed above the level of the existing surrounding
ground surface.'' \26\
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