[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 [www.gpo.gov]
[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:
     Federal eRulemaking Portal: https://www.regulations.gov/ 
(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.
     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.
     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 https://www.regulations.gov/, 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: [email protected]. 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: 
[email protected]. For more information on this rulemaking please 
visit https://www.epa.gov/coal-combustion-residuals.

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 https://www.regulations.gov (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 https://www.regulations.gov 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 https://www.epa.gov/dockets/commenting-epa-dockets 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 (https://www.epa.gov/coal-combustion-residuals) 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 (https://www.epa.gov/coal-combustion-residuals).
    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 (https://www.epa.gov/coal-combustion-residuals) 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 https://www.epa.gov/coal-combustion-residuals. 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:
     $174-$194 million per year when discounting at 3%; and
     $232-$262 million per year when discounting at 7%.
    The RIA estimates that the annualized change in benefits of this 
action will be approximately:
     A $5 million decrease per year when discounting at 3%; and
     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\
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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. https://csce.cust.edu.pk/archive/CSCE_23_conference_proceedings/2023-135.pdf.
    \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:
     The type and volume of CCR and all other materials in the 
unit prior to closure;
     The methods used to verify complete removal of all CCR and 
other contaminated materials from the unit, including any post-removal 
sampling and analysis;
     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;
     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;
     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
     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:
     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.
     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:
     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.
     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:
     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.
     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.
     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.
---------------------------------------------------------------------------

    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, 
https://www.merriam-webster.com/dictionary/roadbed (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.
---------------------------------------------------------------------------

    \25\ CCIG 2025. White paper reflecting Recommendations Updating 
the Federal CCR Regulations. Cross-Cutting Issues Group. June.
---------------------------------------------------------------------------

    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\
---------------------------------------------------------------------------

    \26\ This definition is based off information regarding 
embankments from the U.S. Department of Transportation Federal 
Highway Administration's User Guidelines for Waste and Byproduct 
Materials in Pavement Construction. (Publication Number: FHWA-RD-97-
148)
---------------------------------------------------------------------------

v. Deferral of Certain CCR Management Unit Closures To Permitting
    EPA is requesting comment on whether to make changes to Sec.  
257.101(g) to expand the deferral criteria for CCRMU that completed 
closure of the unit under state or federal regulatory authority prior 
to November 8, 2024. This expansion will provide greater deference to 
the decisions of state and other regulatory authorities regarding

[[Page 18994]]

CCRMU closures completed before the effective date of the Legacy Final 
Rule.
    As explained in Unit IV.A.2.b. of this preamble, in the Legacy 
Final Rule, EPA finalized provisions allowing owners and operators of 
legacy surface impoundments and CCRMU to defer compliance with the 
closure performance standard until the CCR permit authority could make 
a site-specific decision, provided the owner or operator could document 
that the unit closure met certain conditions. This provision allowed 
for 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. See 
Sec.  257.101(g). Specifically, the Legacy Final Rule provided that an 
owner or operator of a legacy CCR surface impoundment or CCRMU 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 specific 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 current 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 applicable 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.
    As discussed in Unit IV.A.2.b. of this preamble, during the Legacy 
Rulemaking, EPA received public comment arguing that state programs had 
become significantly more robust over the past couple of decades, 
specifically, since 2015 when EPA last conducted a review of state 
programs. 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). See Unit IV.A.2.b. 
for more information and examples of information provided by industry.
    If the CCRMU provisions are not rescinded, EPA intends to maintain 
the general procedures in the existing regulations, whereby owners and 
operators of CCRMU 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 and rationale summarized in Unit 
IV.A.2.b. of this preamble, EPA is soliciting comment on extending the 
expanded legacy CCR surface impoundment deferral criteria, as described 
in Unit IV.A.2.b. of this preamble to CCRMU. Specifically, EPA is 
proposing to remove: (1) The detailed technical requirements for a 
groundwater monitoring system, (2) The requirement that a facility 
document that the CCRMU 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. Under this approach, 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 option would lead to an increase in the 
number of CCRMU eligible for deferral. As a result, fewer CCRMU 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 CCRMU 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. The CCR permit authority 
would then make a final determination as to whether the previously 
conducted closure achieved the performance standards established in the 
Federal CCR regulations.
    The alternative would ensure that previous decisions made by state 
or federal regulators remain unaffected until the CCR permitting 
program can conduct site-specific evaluations. Additionally, since most 
of these CCRMU have been in place for decades, delaying potential 
compliance with the federal closure requirements for a comparatively 
short time until a permit authority evaluates the completed closure is 
unlikely to dramatically change the environmental conditions or risks 
at these facilities.
    Therefore, EPA is soliciting comment on the option to allow owners 
or operators of CCRMU 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;

[[Page 18995]]

and groundwater monitoring has been performed to document they meet the 
criteria in an owner-or-operator certified report. If EPA finalizes 
this option, the required documentation will have a deadline of no 
later than six months after the effective date of the final rule, if 
finalized, consistent with the compliance timeframe 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.
    If EPA were to finalize this approach, EPA would apply the same 
deferral criteria to CCRMU as is proposed in Unit IV.A.2.b. for legacy 
CCR surface impoundments. The process for the CCR permitting program to 
make the ``equivalence'' determination or establish additional 
requirements for the CCRMU would remain unchanged.
    Additionally, for the reasons described 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. EPA specifically requests detailed information regarding 
state CCR programs as well as other relevant regulatory programs at the 
points in time that may have overseen CCRMU closures. 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.
vi. Removing ``Other Active Facilities'' From the Regulated Universe
    EPA is soliciting comment on limiting the applicability of the 
CCRMU requirements to facilities that meet the definition of an 
``active facility'' and those with a legacy CCR surface impoundment.
    In the preamble to the Legacy Final Rule, EPA explained its 
decision to extend regulation to certain other facilities currently 
generating power for the electrical grid that only have CCRMU onsite. 
(89 FR 39053). EPA explained that it was concerned that CCRMU (e.g., 
inactive CCR landfills, closed CCR landfills, or closed CCR surface 
impoundments) are located at these facilities. The preamble described 
these facilities as ``other active facilities'' and defined them as 
those that: (1) On or after October 19, 2015, were producing 
electricity for the grid; (2) Had ceased placement of CCR in their 
onsite CCR units before the effective date of the 2015 CCR Rule 
(October 19, 2015); and (3) Had no inactive CCR surface impoundments. 
After promulgation of the Legacy Final Rule, EPA received several 
questions regarding the scope of the active facilities covered under 
Sec.  257.50(d). On January 16, 2025, in response to these questions, 
EPA issued a direct final rule and companion proposed rule to define 
and clarify the scope of the intended ``other active facility'' 
universe (90 FR 4635 and 90 FR 4707). In the direct final rule, EPA 
acknowledged that as currently written the regulation could result in 
the inclusion of electric utilities or independent power producers that 
have not placed CCR onsite or operated an onsite coal-fired electric 
generating unit (EGU). Both the Legacy Final Rule preamble and the 
January 2025 direct final rule clearly stated this was never EPA's 
intent. Rather EPA intended the CCRMU regulations to only apply to 
facilities with a regulated CCR unit and to the small subset of active 
facilities described in the Legacy Final Rule preamble. Indeed, EPA 
specifically declined requests to extend coverage more broadly. See 89 
FR 39053-39054. In response to adverse comment, EPA withdrew the direct 
final rule on March 14, 2025.
    Several commenters on the direct final rule and companion proposal 
expressed greater confusion over EPA's attempt to clarify the 
provision. A few commenters expressed the opinion that the 
clarification went beyond the intended scope of the Legacy Final Rule 
and was overly broad. While others made comments to suggest the scope 
of ``other active facility'' was no different than the scope of 
``active facility''. In light of the discussion in Unit III.D., the 
persistent confusion regarding the scope of the intended ``other active 
facility'' universe, and EPA's inability to clearly articulate the 
intended scope, EPA is soliciting comment on limiting applicability of 
the CCRMU requirements to facilities that meet the definition of 
``active facility or active electric utilities or independent power 
producers'' and those inactive facilities with a legacy CCR surface 
impoundment (i.e., those facilities with a regulated CCR unit onsite).
vii. New Threshold for CCRMU
    In the Legacy Final Rule, EPA deferred decisions about the 
management of CCRMU between one and 1,000 tons to permitting and 
exempted placement less than one ton from further consideration. This 
framework was an outgrowth of the 2024 Risk Assessment, which 
identified potential for groundwater impacts at relatively small 
tonnages, but was unable to reliably identify a discrete point at which 
risks would consistently fall below levels of concern. This uncertainty 
was further compounded by the potential for discrete fills to be 
located in close proximity to other fills and disposal units, resulting 
in a larger effective mass. The promulgated national thresholds were 
intended to address these uncertainties while ensuring no reasonable 
probability of adverse effects to health and the environment.
    As discussed in Unit IV.A.3., several members of industry critiqued 
the existing CCRMU deferral threshold and requested that EPA increase 
the threshold from 1,000 tons to an alternative quantity associated 
with acceptable beneficial use or to risk-based criteria for stability, 
groundwater, and dust. For example, CCIG said the one-ton threshold for 
identification of CCRMU in the FER should be increased as one ton of 
CCR amounts to what could fit in the back of a small pickup truck or a 
single front-end loader bucket. The organization stated there is no 
evidence that CCR in such a low amount poses a risk and imposing the 
regulatory burdens for such small amounts is thus not justified. 
Furthermore, as discussed previously in Unit III.D., EPA acknowledges 
that the high-end risks evaluated in the 2024 Risk Assessment may not 
manifest at every site and concurs that risks associated with 
individual CCRMU fills may be lower. There is potential for even 
greater variability among fills compared to disposal units (e.g., 
thickness, area). The Agency has previously recognized that there are 
limits to the utility of a single mass-based thresholds.\27\ A national 
limit based on any single variable has the potential to become overly 
restrictive, as that limit must simultaneously account for the effects 
of any other variables that could influence risk (e.g., leachate 
concentration). Conversely, attempting to simultaneously control for 
multiple variables can quickly yield limits that are unwieldly to 
define and implement. As a result, to date, EPA has been

[[Page 18996]]

unable to identify a less onerous threshold that is also reliably 
protective.
---------------------------------------------------------------------------

    \27\ 89 FR 38950, May 8, 2024.
---------------------------------------------------------------------------

    EPA is soliciting comment on alternate thresholds for exemption of 
CCRMU fills from regulation that would be applicable nationwide. EPA is 
specifically requesting comment on specific limits that could be 
established, numerical or otherwise, as well as the basis for why there 
would be no reasonable probability these placements would have an 
adverse effect on human health or the environment if no further action 
is taken to monitor or maintain these fills.
4. Initial Timeframes for Background Sampling for New CCR Landfills, 
CCR Surface Impoundments, and any Lateral Expansions
    EPA is proposing to amend the existing regulations to clarify that 
the deadline by which new CCR landfills and CCR surface impoundments 
(which includes any lateral expansions) must comply with 40 CFR 257.90 
through 257.94 is the deadline in Sec.  257.90(b)(2) (``prior to 
initial receipt of CCR'') rather than the deadline in Sec.  257.94(b). 
This proposed revision is consistent with EPA's original intent, as 
described in the final rule preamble. 80 FR 21408. This six-month 
deadline is also in tension with the requirement to obtain eight 
statistically independent samples, as six months can be too short a 
time to complete this task.
    The current regulations contain an error. The first sentence of 
Sec.  257.90(b)(2) provides that ``Prior to initial receipt of CCR by 
the CCR unit, the owner or operator must be in compliance with the 
groundwater monitoring requirements specified in paragraph (b)(1)(i) 
and (ii) of this section.'' The second sentence requires the owner or 
operator of the CCR unit to initiate the detection monitoring program 
``to include obtaining a minimum of eight independent samples for each 
background well as required by Sec.  257.94(b).'' Unfortunately, Sec.  
257.94(b) specifies that ``a minimum of eight independent samples for 
each background well must be collected and analyzed for the 
constituents listed in appendices III and IV to this part during the 
first six months of sampling.'' (emphasis added). The requirement that 
background sampling and analysis be conducted during the first six 
months was an error; as evidenced by the explanation in the 2015 final 
rule preamble, EPA did not intend to require anything more specific 
than that these tasks be completed prior to the initial receipt of CCR.
    In the preamble to the 2015 CCR Rule, EPA provided an overview of 
all the new groundwater monitoring deadlines established in the rule. 
EPA specifically explained that ``new CCR units must comply with 
Sec. Sec.  257.90 through 257.93, including the requirement under Sec.  
257.94(b) to collect and analyze eight independent samples from each 
well for the parameters listed in appendix III and IV to this part to 
determine background levels for all appendix III and IV constituents, 
before commencing operation.'' 80 FR 21408 (emphasis added). Notably, 
EPA never mentioned a requirement that the background sampling and 
analysis be conducted ``during the first six months of sampling,'' or 
explained the reason that these activities specifically need to be 
completed within the first six months, rather than before the facility 
begins using the new unit.
    Moreover, the six-month deadline may not provide enough time to 
collect eight statistically independent samples. As discussed in the 
Legacy Final Rule regarding the compliance deadline for legacy CCR 
surface impoundments to comply with the groundwater monitoring 
requirements, EPA acknowledged that collecting eight statistically 
independent samples can be impacted by third-party availability and 
laboratory backlogs. Furthermore, EPA acknowledged the adverse impact 
of too frequent sampling on the validity of statistical analysis, the 
need to account for seasonal variability in groundwater flow, 
groundwater levels, and constituent concentrations and that providing 
insufficient time for the collection of baseline samples would likely 
result in ineffective groundwater monitoring programs that may fail to 
alert facilities to groundwater contamination coming from CCR units. 89 
FR 39019.
    Accordingly, EPA is proposing to revise Sec.  257.90(b) to state 
that, ``In addition, prior to initial receipt of CCR, the owner or 
operator of the CCR unit must collect and analyze eight independent 
samples from each well for the parameters listed in appendix III and IV 
to this part to determine background levels for all appendix III and IV 
constituents, and initiate the detection monitoring program in Sec.  
257.94.'' EPA is further proposing to revise Sec.  257.94(b) to 
reference Sec.  257.90(b)(2).
5. Slope Stability Requirements for Vegetation
    In 2015, EPA promulgated requirements for all CCR surface 
impoundments (except incised units) to install and maintain adequate 
slope protection. Specifically, the final rule required facilities to 
document that ``the CCR unit has been designed, constructed, operated, 
and maintained with . . . adequate slope protection to protect against 
surface erosion, wave action, and adverse effects of sudden drawdown.'' 
40 CFR 257.73(d)(1)(ii); 257.74(d)(1)(ii). In developing the 2015 CCR 
Rule, EPA relied on existing dam safety technical literature, which 
universally recommends that vegetative cover not be permitted to root 
too deeply beneath the surface of the slope. Deep roots can potentially 
introduce internal embankment issues such as pathways for water 
intrusion and piping, precipitating erosion internally, or uprooting 
which is the disruption of the embankment due to the sudden uplifting 
of the root system. Based on these data, the final rule also required a 
vegetative cover height limitation to prevent the establishment of 
rooted vegetation, such as a tree, a bush, or a shrubbery, on the CCR 
surface impoundment slope (80 FR 21476, April 17, 2015), and to prevent 
the obscuring of the slope during routine and emergency inspection. 
Based on the available information, EPA concluded that a vegetative 
cover height limitation of six inches above the face of the embankment 
would prevent woody vegetation, while allowing inspectors adequate 
observation of the slope.
    After the 2015 final rule was published, the six-inch vegetative 
height limitation was challenged on the ground that EPA had failed to 
provide adequate notice of this requirement in the proposal. See, USWAG 
et al. v. EPA, No. 15-1219 (D.C. Cir. 2015). In response, EPA agreed to 
reconsider this provision. This claim was settled, and the court 
vacated the requirement that vegetation on all slopes ``not . . . 
exceed a height of 6 inches above the slope of the dike'' within 
Sec. Sec.  257.73(a)(4), 257.73(d)(1)(iv), 257.74(a)(4), and 
257.74(d)(1)(iv).
    In 2018, EPA proposed to expand on the existing general performance 
standard with more specific slope protection requirements for existing 
and new surface impoundments. EPA also proposed to establish distinct 
definitions and height limitations for grassy vegetation and woody 
vegetation to replace the vacated requirement. See 83 FR 11589-11592. 
EPA never finalized this requirement and the proposal remains pending. 
EPA is now soliciting comment on whether these proposed performance 
standards would still be necessary and useful or whether EPA should 
instead rely on a permit authority to establish the necessary terms and 
conditions to ensure slope protection.

[[Page 18997]]

B. New Compliance Pathway Allowing Site-Specific Considerations During 
Permitting

    The majority of state and industry commenters on the proposal that 
resulted in the 2015 CCR rule preferred regulations that would allow 
site-specific approaches to establishing standards. (See 80 FR 21331-
21234) Commenters argued that the prescriptive one-size-fits-all 
approach was overly stringent and inflexible and had the potential to 
greatly disrupt implementation of a state's regulatory programs, which 
have been tailored to provide for site specific conditions and 
situations. Moreover, commenters argued that because of the many state 
regulatory programs addressing CCR disposal, there would be many 
instances where state requirements could be in conflict with, in 
addition to, or separate from the federal requirements and it was 
unclear how these differences would be resolved.
    Many commenters simply argued that a permitting program was the 
only viable approach for the regulation of CCR. Commenters argued that 
states should be allowed to enforce compliance through a traditional 
permitting system, and that solid waste operating permits are critical 
to ensuring coal ash disposal facilities design, construct, operate and 
close their waste facilities safely. Commenters argued that permits are 
important because they can dictate the use of specific operating 
practices and control technologies that may be essential for minimizing 
releases. Permits also provide an important enforcement vehicle, as 
well as a process by which the public can be informed and participate 
in the siting, operation and closure of the waste disposal unit.
    In the 2015 CCR final rule, EPA expressed appreciation for 
commenters' attempts to craft alternative approaches to address the 
limitations in the proposed self-implementing subtitle D option and 
recognized that this regulatory structure gives rise to legitimate 
concerns about the potential for duplicative or conflicting state and 
federal regulatory systems. However, as EPA noted at the time, the 
Agency did not have the authority to pursue such alternative 
approaches.
    However, the subsequent passage of the WIIN Act changed the 
landscape of EPA's authority. As explained in Units III.A. and III.D. 
of this preamble, the 2016 WIIN Act provided EPA new tools to pursue 
its regulatory goals. Namely, the WIIN Act empowered EPA to authorize 
states to implement the federal CCR rule through an EPA-approved permit 
program, and to act as the CCR permit authority, once a permit program 
is established, in Indian Country and in nonparticipating states. With 
regulatory oversight by a permit authority and the interpretation of 
section 4004(a) as requiring a baseline standard of protection without 
mandating uniformity in the manner of attainment, EPA is justified in 
moving away from the ``one-size-fits-all'' regulatory approach 
previously necessitated by the self-implementing rule structure and 
creating another pathway to compliance that incorporates regulatory 
provisions that allow permit authorities the ability to approve a 
different combination of technical standards for the owner or operator 
to comply with while still attaining the RCRA standard of ``no 
reasonable probability of adverse impacts''. These permit authority-
approved flexibilities are necessary to accommodate site-specific 
conditions and are in line with EPA's interpretations of section 
4004(a) to allow for non-uniformity in attainment of the statutory 
directive to prevent ``reasonable probabilities of adverse effects to 
health and the environment'' from the disposal of CCR.
    When using the term permit flexibilities, EPA intends to convey the 
concept that the permit authority, whether a participating State or 
EPA, will be able to adjust or adapt certain technical requirements 
based on site-specific facts and risks. Such adjustments will still 
need to remain within the boundaries set by the regulatory standard and 
must support a determination by the permit authority that compliance 
with the permit terms will ``not result in a reasonable probability of 
adverse impacts to human health or the environment.''
    While EPA is proposing and soliciting comment on several regulatory 
flexibilities for permit authorities to elect to apply to eligible 
owners or operators of CCR units, owners or operators of CCR units must 
still comply with all requirements in the existing regulations for 
which the permit authority does not approve flexibility for, in 
accordance with the proposed provisions below, this includes all 
recordkeeping, notification, and internet posting requirements in 
Sec. Sec.  257.105 through 257.107. The new compliance pathway set 
forth in this proposed rule will take effect only once a final CCR 
permit that establishes the final technical requirements for the CCR 
unit is in effect. Until such time, the Agency will assess compliance 
with the existing applicable regulatory requirements and seek such 
compliance through appropriate enforcement action where necessary.
    To be clear, the site-specific considerations in the new compliance 
pathway will apply to any facility only after a permit application is 
properly submitted, the permit authority determines the appropriate 
permit provisions, and a final CCR permit incorporating those 
provisions is in effect. For States with an EPA-approved CCR permit 
program and who wish to adopt the new compliance pathway (i.e., permit 
flexibilities), the State will have to submit an updated application 
that includes the provisions in this rule and the Agency will have to 
grant updated approval of that State program. The State will then have 
to initiate the permitting process and then properly consider the 
applicability and appropriateness of any flexibility in this rule. For 
States without an approved program but are planning to submit a program 
application, that application must be approved, and the State then will 
consider the flexibilities through a permit process. For States that do 
not seek program approval, EPA will have to finalize the regulations 
establishing the Federal permit program and then consider the 
flexibilities in the context of facility specific permit decisions.
1. Groundwater Monitoring and Corrective Action Requirements
    EPA is proposing to codify permit flexibilities for units under a 
federal or participating-state CCR permit. These revisions would allow 
the permit authority to establish: (1) An alternative point of 
compliance for the groundwater monitoring wells required to comply with 
the federal CCR groundwater monitoring and corrective action 
requirements in 40 CFR part 257, and (2) Alternative groundwater 
protection standards for constituents for which a federal MCL has not 
been established under the regulations referenced at Sec.  257.95(h)(1) 
(i.e., Sec. Sec.  141.62 and 141.66).
a. Point of Compliance for Groundwater Monitoring and Corrective Action
    EPA is proposing several revisions to allow the Participating State 
Director or EPA, when serving as the permit authority, to establish 
alternative points of compliance of no more than 150 meters from the 
waste boundary for locating groundwater monitoring wells and 
demonstrating compliance with the groundwater monitoring and corrective 
action standards in 40 CFR part 257. Additionally, EPA is soliciting 
comments on an alternative that would, under specific circumstances, 
allow the permit authority to establish points of

[[Page 18998]]

compliance for groundwater monitoring and corrective action no further 
from the unit than the facility boundary, while exploring ways in which 
this approach could be implemented in a manner that ensures early 
detection (e.g., by installing additional wells) and minimizes 
groundwater contamination.
    The existing groundwater monitoring and corrective action 
regulations require the installation of a system of monitoring wells 
and specify procedures for sampling these wells, along with methods for 
analyzing the collected groundwater data to detect the presence of 
hazardous constituents (e.g., toxic metals) and other monitoring 
parameters (e.g., pH, total dissolved solids) released from the units. 
These regulations establish a comprehensive groundwater monitoring 
program comprised of detection monitoring, assessment monitoring, and 
corrective action. Once a groundwater monitoring system and groundwater 
monitoring program have been established for a CCR unit, the owner or 
operator must conduct groundwater monitoring and, if the monitoring 
reveals an exceedance of a groundwater protection standard at a 
statistically significant level for any of the constituents listed in 
appendix IV, must initiate corrective action.
    Specifically, the groundwater monitoring systems regulations in 
Sec.  257.91 establish a general performance standard requiring that 
all CCR units have a groundwater monitoring system consisting of a 
sufficient number of wells, installed at appropriate locations and 
depths, to collect groundwater samples from the uppermost aquifer. This 
system must accurately represent both the quality of background 
groundwater and the quality of groundwater passing the waste boundary 
of the CCR unit. Its primary objective is to detect a release early, 
enabling timely corrective action before sensitive receptors are 
significantly affected. To achieve this, the regulations require that 
downgradient wells be placed at the waste boundary, which is defined as 
the vertical surface located at the hydraulically downgradient limit 
(i.e., the edge) of the CCR unit, extending down into the uppermost 
aquifer. These downgradient wells are used to monitor for any 
contaminants leaking or seeping into the groundwater.
    Additionally, under the existing regulations in Sec.  257.91, each 
CCR unit must have its own groundwater monitoring system, unless the 
owner or operator chooses to install a multiunit groundwater monitoring 
system. The existing rule specifies that if a multiunit system is 
installed, it must be equally capable of detecting background and 
groundwater contamination at the waste boundary as an individual 
monitoring system, 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.
    There are two main reasons why EPA is proposing increased 
flexibility in establishing the location of the groundwater monitoring 
systems and ensuring compliance with the groundwater and corrective 
action standards in 40 CFR part 257.
    First, as discussed in Units III.D. and IV.B. of this preamble, the 
WIIN Act provided EPA with new tools, including critical oversight 
mechanisms while preserving the interpretation of section 4004(a) as 
requiring a baseline standard of protection without mandating 
uniformity in how it is achieved. Furthermore, as explained in Unit 
III.D. of this preamble, EPA maintains broad discretion to adopt 
performance-based criteria based on a record of protectiveness across 
various state instances. In developing the 2015 CCR Rule, EPA 
promulgated performance standards that provided only a limited degree 
of flexibility in line with a self-implementing regulatory structure to 
ensure that requested modifications are protective and technically 
appropriate.\28\ EPA largely based the proposed groundwater monitoring 
requirements on those for MSWLFs in the 40 CFR part 258 criteria, 
albeit with certain modifications to tailor the requirements to the 
self-implementing CCR regulatory structure. In particular, EPA did not 
include some of the alternatives available in part 258, which establish 
alternative standards allowing a state, as part of its permit program, 
to tailor the default requirements to account for site-specific 
conditions at the individual facility.\29\ Thus, EPA adapted the 
proposed requirements for CCR units by incorporating certain provisions 
from the 40 CFR part 265 interim status regulations, which operate in 
the absence of a permit, and by including, in several of the proposed 
requirements, a certification by an independent registered professional 
engineer that the rule's requirements had been met.\30\
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    \28\ The 2015 CCR Rule was designed to be self-implementing, 
meaning that the requirements allowed facilities to comply with the 
regulations without the need to interact with a regulatory 
authority.
    \29\ In both the proposal and the final 2015 CCR Rule, EPA 
indicated that in the absence of a mandated state oversight 
mechanism to ensure that suggested modifications are technically 
appropriate, these kinds of provisions could operate at the expense 
of safety and environmental protection. 80 FR 21398, April 17, 2015.
    \30\ 80 FR 21396, April 17, 2015.
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    With the new tools provided by the enactment of the WIIN Act, EPA 
now has the authority to issue permits, enforce the regulations, and 
approve state CCR permit programs; consequently, there are now 
regulatory-based oversight mechanisms to allow for alternative 
compliance pathways, such as an approved alternative boundary, while 
ensuring the actions pose no reasonable probability of adverse effects 
to health and the environment. Prior to the WIIN Act, the only 
enforcement mechanism was through filing a citizen suit under RCRA 7002 
which would have been initially based on the information available on 
the facility's website.
    Second, the Agency has received feedback from industry indicating 
that precisely defining the unit boundary of some units, particularly 
older legacy surface impoundments, can be challenging. In some 
instances, waste boundaries were established decades ago based on 
natural features that may now be obscured or have changed over time. 
According to industry, depending on the circumstances, location and 
physical characteristics of a unit, it may be beneficial to move the 
point of compliance downgradient to a distance where uncertainties 
along the waste boundary are minimized, including ensuring that 
monitoring wells are not inadvertently placed into the waste.
    Furthermore, EPA is aware that, for certain facilities, the waste 
boundary may not always serve as the most effective point of compliance 
for groundwater monitoring. Accessibility issues may arise due to 
physical obstacles such as gas and power lines or site design 
constraints such as run-off controls and liner anchors. Additionally, 
perched water tables or other hydrogeologic phenomena may cause 
leachate from a CCR unit to travel laterally for a significant distance 
before reaching the uppermost aquifer. In such cases, a monitoring 
system installed solely at the waste boundary could potentially miss 
all or significant portions of a contaminant plume.
    In considering the development of this proposal, EPA reviewed many 
state CCR and municipal solid waste regulatory programs, such as 
Florida, Illinois, North Dakota, Tennessee, North Carolina, and 
Wyoming, and identified several that have allowed monitoring points of 
compliance beyond the waste boundary. This element of a groundwater 
monitoring system is not surprising as a monitoring well placed

[[Page 18999]]

near rather than at the boundary of a waste unit can detect a release 
from a broader area. When developing the self-implementing CCR rules, 
EPA determined that using the waste boundary location and qualified 
engineer certification represented a standard that was implementable 
without regulatory oversight or involvement. Now with the authority to 
both issue permits and enforce the technical standards and the ability 
of EPA to allow for non-uniformity in attaining the RCRA protectiveness 
standard, EPA is proposing a second approach to allow for the permit 
authority to adjust the technical standards (such as the alternative 
point of compliance for groundwater monitoring and corrective action).
    Recognizing these site-specific situations and considering the 
additional authorities provided by the WIIN Act of 2016, EPA is 
proposing a regulatory amendment that would allow the Participating 
State Director or EPA, when serving as the permit authority, to 
establish alternative points of compliance that are no more than 150 
meters from the waste boundary and located on the facility, only if the 
Director finds, based on specific criteria and a demonstration by the 
owner or operator, that the alternative point of compliance, together 
with location characteristics, will (1) Not materially delay detection 
of either a statistically significant increase over background levels 
for a constituent in appendix III or statistically significant levels 
above the groundwater protection standard of any of the constituents 
listed in appendix IV from that CCR unit and (2) Minimize the migration 
of any of those constituents from that CCR unit to the uppermost 
aquifer during the active life of the CCR unit and the post-closure 
care period based on specific criteria. Authorizing a permit authority 
to establish an alternate point of compliance within 150-meters of a 
CCR unit aligns with current regulations governing very small quantity 
generators (40 CFR part 257, subpart B, Disposal Standards for the 
Receipt of Very Small Quantity Generator Wastes at Non-Municipal Non-
Hazardous Waste Disposal Units) and MSWLFs (40 CFR part 258, Criteria 
for Municipal Solid Waste Landfills). Additionally, while requiring a 
monitoring well at the waste boundary works well within a self-
implementing program with no permit authority oversight, it results in 
a very limited zone of detection for each well. A single monitoring 
well placed at the very edge of the CCR unit is only capable of 
detecting a release from a small portion of the CCR unit and any 
release would need to be in close proximity to the well. Alternately, a 
well placed further away from the edge of the CCR unit can be capable 
of detecting releases from a larger portion of the CCR unit when the 
release migrates as it expands horizontally (i.e. spreads out). At the 
other end of the spectrum, placing a well a significant distance (e.g., 
one mile) downgradient will be unlikely to detect many releases as the 
plume spreads out and its impacts are diluted over space. Consequently, 
having a limit is essential for avoiding the effects of delayed 
detection such as preventing large expanses of contamination, costly 
cleanups, and potential new Superfund sites. Delayed detection of a 
release or leak could increase the likelihood of contamination 
spreading over a larger area. When there is a significant distance 
between the source of contamination (e.g., the CCR unit) and the point 
of detection (e.g., monitoring wells), more land may become 
contaminated before the issue is identified. In extreme cases, large-
scale contamination could result in the site being designated as a 
Superfund site.
    By setting a maximum distance limit, EPA aims to enhance regulatory 
flexibility for CCR unit owners and operators, based on established 
criteria while still having a system that will timely identify a 
release. These criteria are designed to help the permit authority 
determine appropriate groundwater monitoring points of compliance 
(i.e., groundwater monitoring well locations) to accommodate site-
specific conditions while maintaining protection against adverse 
effects to health and the environment. The criteria are as follows:
     Consideration of the facility's hydrogeological features 
and surrounding land, including aquifer attenuation and dilution 
characteristics;
     Adherence to location restrictions as specified in 
Sec. Sec.  257.61 through 257.64;
     Compliance with corrective action procedures outlined in 
Sec. Sec.  257.96 through 257.98;
     Assessment of the volume and physical and chemical 
characteristics of the leachate;
     Evaluation of the quantity, quality, and direction of 
groundwater flow underlying the facility;
     Consideration of the proximity and withdrawal rates of 
groundwater users;
     Availability of alternative drinking water sources;
     Analysis of existing groundwater quality, including other 
sources of contamination and their cumulative impacts; and
     Evaluation of public health, safety, and welfare effects.
    In developing this proposal, EPA reviewed various EPA regulations 
that authorize a permit authority to establish an alternative point of 
compliance. Historically, EPA has recognized that fixed compliance 
boundaries may not be universally applicable due to the diverse 
geological and operational characteristics of waste management 
facilities. For example, under the framework of 40 CFR part 257, 
subpart A (Criteria for Classification of Solid Waste Disposal 
Facilities and Practices), States with approved Solid Waste Management 
plans may establish an alternative boundary if, after thorough 
examination of the site-specific situation, a finding is made that an 
adjustment of the boundary would not result in contamination of 
groundwater needed or used for human consumption.
    In the preamble to the 1979 final rule establishing this 
regulation, EPA evaluated various options for the point of compliance 
(i.e., at what point in the aquifer does contamination from the 
facility or practice constitute non-compliance), including use of other 
distance specifications in lieu of the property boundary in order to 
try to respond to reviewers' concerns about the potential for 
contamination of large expanses of groundwater.\31\ The proposal 
requested comments on alternative distances and the rationale for 
specification of such distances. Various distances were suggested in 
the public comments to the proposed rule; however, no basis was 
presented for selection of one distance over another at that time. 
While there was a rationale for limiting migration of contamination to 
within the designated waste disposal areas to protect neighbors who may 
use the untreated groundwater as drinking water supply, there was no 
rationale for limiting migration to any particular distance. In 
evaluating this issue EPA recognized that the point of compliance must 
be established at a point at which it is feasible to monitor. Ideally, 
the best way to protect present and future users of an aquifer is to 
ensure that drinking water standards are not violated anywhere in the 
aquifer, including the area immediately under the waste material. 
However, in the 1979 preamble EPA indicated that any attempt to monitor 
directly under the waste would present two major difficulties. First, 
an environmental risk may be posed by the installation of monitoring 
wells through the waste

[[Page 19000]]

material or in areas where waste will be deposited. EPA was concerned 
that such wells may become conduits for direct flow of waste 
constituents (e.g., leachate) into the aquifer. EPA also stated that, 
while it may be theoretically possible to construct a well that doesn't 
allow such infiltration, the technology for this had not been 
sufficiently demonstrated that EPA would want to encourage this 
practice on a national scale. Secondly, the immediate proximity of 
waste to the well, in conjunction with the ``conduit'' phenomenon, 
would undermine the utility of the monitoring well. Samples extracted 
would not be likely to be representative of the aquifer; rather, they 
would be likely to contain concentrated leachate, overestimating the 
contamination of the aquifer.
---------------------------------------------------------------------------

    \31\ 44 FR 53447, September 13, 1979.
---------------------------------------------------------------------------

    EPA also examined the possibility of other fixed distances from the 
center of the waste area.\32\ This approach was rejected because it was 
impossible to establish a uniform distance that would be meaningful for 
the vast number of situations to which this standard applied. In some 
instances, a fixed distance would mean that monitoring wells would 
still be placed through waste material. A longer distance might, in 
some cases, put the point of compliance beyond the area of likely 
placement of drinking water wells.
---------------------------------------------------------------------------

    \32\ 44 FR 53448, September 13, 1979.
---------------------------------------------------------------------------

    After examining all these approaches, EPA concluded that the solid 
waste boundary was the appropriate point for application of the 
standard. With that as the point of compliance, groundwater 
contamination would be detected as soon as possible without presenting 
the risks inherent in monitoring under the waste. Likewise, it avoided 
the problem of guessing the distance at which a potentially affected 
party is likely to put a drinking water well.
    However, in the 1979 final rule, EPA recognized the need for some 
flexibility to allow States with approved solid waste management plans 
to establish an alternative boundary if, after a thorough examination 
of the site-specific situation, it is determined that adjusting the 
boundary would not result in contamination of groundwater needed or 
used for human consumption. Accordingly, the existing Solid Waste 
Disposal regulations in Sec.  257.3-4(b)(2) permit an approved State to 
set an alternative boundary for a facility, replacing the solid waste 
boundary, only if it is found that this change will not result in the 
contamination of groundwater intended for human consumption. This 
determination must be based on an analysis and consideration of factors 
outlined in Sec.  257.3-4(b), including: (1) The hydrogeological 
characteristics of the facility and surrounding land, (2) The volume 
and physical and chemical characteristics of the leachate; (3) The 
quantity, quality, and direction of flow of groundwater underlying the 
facility; (4) The proximity and withdrawal rates of ground-water users; 
and (5) Public health, safety, and welfare effects.
    The Agency also considered moving the point of compliance in 1991 
when revisions were made to the Criteria for Classification of Solid 
Waste Disposal Facilities and Practices set forth in 40 CFR part 257, 
in response to the 1984 Hazardous and Solid Waste Amendments to RCRA. 
This action also introduced a new part 258, which established revised 
minimum federal criteria for MSWLFs, including requirements for 
groundwater monitoring.
    In the 1991 final rule, EPA set a maximum distance from the MSWLF 
for establishing the alternative boundary or relevant point of 
compliance. During the public comment period of this rule, the Agency 
received a number of comments regarding the alternative boundary 
designation, which would allow groundwater monitoring wells to be 
placed at distances up to 150 meters from the waste management unit 
boundary.\33\ Several commenters argued that the 150-meter boundary was 
overly conservative and inflexible. Several commenters suggested other 
alternative boundary locations including: the property boundary and 
unlimited locations, based on the risks posed by the facility. These 
arguments were countered, however, by other commenters who expressed 
concern that the allowable distance was excessive, would simply allow 
dilution of contamination, and would delay detection of contamination.
---------------------------------------------------------------------------

    \33\ 56 FR 51068, October 9, 1991.
---------------------------------------------------------------------------

    In the final rule, the Agency ultimately disagreed with commenters 
who argued that the proposed approach was unnecessarily stringent. In 
developing the proposed rule, EPA considered setting the alternative 
boundary at the property boundary or not stipulating any limit. These 
options obviously would provide the greatest flexibility in addressing 
the practicable capability of owners and operators of MSWLFs. However, 
due to the size of some MSWLF facilities, EPA was concerned that large 
expanses of groundwater could be contaminated before detection. Thus, 
the Agency believed it was essential to set a maximum distance limit 
for the alternative boundary (referred to in the MSWLF rule as the 
``relevant point of compliance'') that would limit groundwater 
contamination yet still provide some flexibility to owners and 
operators of MSWLFs. The Agency also specified in the final rule that 
the alternative boundary (or the relevant point of compliance) must be 
located on property owned by the owner or operator to prevent 
contamination off site. The Agency believed this approach provided 
sufficient flexibility, while at the same time, limiting the area of 
contamination.
    The existing MSWLF regulations in part 258 also specify that, in 
determining the point of compliance, the Director of an approved state 
shall consider several factors, including: (1) The hydrogeologic 
characteristics of the facility and surrounding land; (2) The volume 
and physical and chemical characteristics of the leachate; (3) The 
quantity, quality, and direction, of flow of groundwater; (4) The 
proximity and withdrawal rate of the groundwater users; (5) The 
availability of alternative drinking water supplies; and (6) The 
existing quality of the groundwater, including other sources of 
contamination and their cumulative impacts on the groundwater, and 
whether the groundwater is currently used or reasonably expected to be 
used for drinking water. Under part 258, subpart E, multiunit 
monitoring systems must consist of a sufficient number of wells, 
installed at appropriate locations and depths, to yield groundwater 
samples from the uppermost aquifer that represent the quality of 
background groundwater and the quality of groundwater passing the 
relevant point of compliance. Section 258.51(a)(2) requires that the 
downgradient monitoring system be installed at the relevant point of 
compliance (not to exceed 150 meters from the unit on land owned by the 
owner or operator) designated by an approved State. In determining 
where to place monitoring wells in a multiunit facility in compliance 
with Sec.  258.51(a)(2), the approved State draws an imaginary line 
around all units at the facility. This line would constitute the 
relevant point of compliance for a multiunit system. Therefore, wells 
must be placed at this imaginary line. Of course, the approved State 
must first make the determination that it is appropriate and protective 
to use a multiunit monitoring system based on the factors described 
above.
    Therefore, considering the information above, the ability of EPA to 
allow for non-uniformity in attaining the RCRA protectiveness standard, 
and the new tools provided to EPA by the

[[Page 19001]]

WIIN Act, EPA is proposing to allow the permit authority to establish 
alternative points of compliance for groundwater monitoring and 
corrective action of no more than 150 meters from the waste boundary, 
provided certain criteria are met. This approach is also similar to 
current regulations governing other solid waste disposal 
facilities.\34\
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    \34\ Solid waste disposal facilities (40 CFR part 257, subpart 
A, Classification of Solid Waste Disposal Facilities and Practices), 
VSQGs (40 CFR part 257, subpart B, Disposal Standards for the 
Receipt of Very Small Quantity Generator Wastes at Non-Municipal 
Non-Hazardous Waste Disposal Units) and MSWLFs (40 CFR part 258, 
Criteria for Municipal Solid Waste Landfills).
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    In developing this proposal, EPA is contending with two main 
considerations: site-specific flexibility, which would be approved by 
the permit authority based on criteria, and the need for early 
detection. Therefore, establishing a maximum distance from the waste 
boundary is essential to avoid delaying detection. However, EPA is 
soliciting comments on what set distance (other than 150 meters) may be 
most appropriate for CCR units.
    Additionally, the Agency solicits comment on an alternative that 
would allow the permit authority to establish the alternative point of 
compliance for groundwater monitoring and corrective action no further 
from the CCR unit than the facility boundary (rather than the 150-meter 
limit). Specifically, EPA is seeking comments on how the facility-
boundary approach could be implemented. In the preamble to the 1979 
final rule establishing the Sec.  257.3-4 (Criteria for Classification 
of Solid Waste Disposal Facilities and Practices) regulations, EPA 
initially considered setting the point of compliance at the facility 
property boundary.\35\ However, concerns were raised about future 
property owners potentially using contaminated groundwater as a 
drinking source, the possibility of large expanses of groundwater 
contamination if the facility property was extensive, and the potential 
for owners purchasing additional property to delay corrective action.
---------------------------------------------------------------------------

    \35\ 44 FR 53445, September 13, 1979.
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    Therefore EPA, seeks comments on strategies to prevent potential 
widespread groundwater contamination and to ensure early detection and 
timely corrective action in cases where the alternative point of 
compliance is located further away from the waste boundary, 
specifically when the facility property is extensive or if units are 
sold off or parceled before contamination is detected. For example, 
some state programs also authorize a buffer zone or a ``zone of 
discharge,'' which allows the facility to defer remediation of 
groundwater contamination for some period of time, usually until the 
contaminant plume has migrated to the facility site boundary. Florida, 
Illinois, North Dakota, and Tennessee are among those states with such 
a regulatory provision.
    Further, EPA is soliciting comment on whether it would be 
beneficial to allow the permit authority to combine groundwater 
monitoring and corrective action systems for all types of CCR units 
into zones (i.e., the equivalent of ``area(s) of concern'' or `solid 
waste management area'') for the purpose of groundwater monitoring and 
corrective action. This flexibility would be especially relevant in 
situations where the CCR surface impoundment or CCR landfill is 
situated among CCRMU, a release has occurred, and both the regulated 
CCR unit and the CCRMU are likely contributors to the release (i.e., 
commingled releases). EPA specifically requests examples where the 
permit authority may prefer to combine CCRMU with other types of CCR 
units, such as CCR surface impoundments, CCR landfills, and legacy CCR 
surface impoundments, across the facility into a single groundwater 
monitoring and corrective action zone, essentially creating a facility-
wide groundwater monitoring network.
    Lastly, EPA solicits comments on whether lateral expansions, new, 
or replacement CCR units should be ineligible for an alternate point of 
compliance for groundwater monitoring and corrective action. The Agency 
believes that owners and operators of these CCR units should be able to 
account for the presence of structures or obstacles during the planning 
process and should be able to place monitoring wells at the closest 
practical distance from the relevant waste boundary. However, this may 
not be true for existing units that were constructed without 
considering the need for groundwater monitoring well installation. 
Therefore, the Agency is requesting comment on whether the flexibility 
to establish an alternative boundary should be limited to existing CCR 
units.
b. Groundwater Protection Standards for Corrective Action
    EPA is proposing two new provisions at Sec.  257.111. The first 
provision would allow the permit authority to establish alternative 
groundwater protection standards, based on specific criteria, for 
constituents for which a federal MCL has not been established under 
Sec. Sec.  141.62 and 141.66 as referenced at Sec.  257.95(h)(1). The 
second provision would require the permit authority to consider 
additional factors when establishing alternative groundwater protection 
standards, including the presence and concentrations of other 
contaminants in the groundwater.
    Under the existing regulations, if groundwater monitoring 
demonstrates an exceedance of the groundwater protection standards for 
constituents identified in appendix IV of part 257 above a 
statistically significant level, corrective action is required, as laid 
out in Sec. Sec.  257.96 through 257.98. These requirements apply 
throughout the active life and any post-closure care period of the CCR 
unit.
    As stated in the preamble to the 2010 CCR Proposed Rule, in EPA's 
view, the objectives of a groundwater monitoring and corrective action 
regime, along with the analytical techniques for evaluating groundwater 
quality, are similar regardless of the specific wastes in a disposal 
unit or whether the unit is a landfill or surface impoundment. 
Therefore, EPA largely modeled the 2010 proposed groundwater monitoring 
and corrective action requirements for CCR landfills and surface 
impoundments after those for MSWLFs in the 40 CFR part 258 
criteria.\36\ At the same time, however, EPA was mindful of the 
differences in the statutory authorities for establishing criteria for 
CCR landfills and surface impoundments versus MSWLFs and very small 
quantity generator (VSQG) facilities, and in particular, the 
possibility that a state may lack a permit program for CCR disposal 
units. Accordingly, EPA sought to tailor the CCR requirements to 
account for the self-implementing framework. EPA chose to include 
requirements for a certification by a qualified professional engineer 
or, in some cases, hydrologist, in lieu of the state approval 
mechanisms that are used in the 40 CFR part 258/257, subpart B 
criteria.
---------------------------------------------------------------------------

    \36\ 75 FR 35204, June 21, 2010.
---------------------------------------------------------------------------

    In the 2010 CCR Proposed Rule, EPA included a provision in Sec.  
257.95 allowing the owner or operator to establish an alternative 
groundwater protection standard for constituents for which federal MCLs 
have not been established under the Safe Drinking Water Act, provided 
that the alternative groundwater protection standard had been certified 
by a qualified professional engineer and the state had been notified 
that the alternative groundwater protection standard was placed in the 
operating record and on the owner's or operator's publicly accessible 
internet site. This provision had been adopted from the part 258

[[Page 19002]]

regulations. However, it was not finalized in the 2015 CCR Rule because 
the Agency determined that it was inappropriate for a self-implementing 
rule, as it was unlikely that a facility would have the scientific 
expertise necessary to conduct a risk assessment, and it was too 
susceptible to potential abuse.\37\ Additionally, numerous comments 
were received suggesting that only those constituents with federal MCLs 
be included in appendix IV because only federal MCLs would be 
enforceable under a self-implementing rule.
---------------------------------------------------------------------------

    \37\ 80 FR 21405, April 17, 2015.
---------------------------------------------------------------------------

    However, as discussed in Units III.A., III.D., and IV.B., now that 
EPA has the authority to issue permits, enforce the regulations, and 
review and approve state CCR permit programs, which can serve as 
oversight mechanisms to evaluate site-specific conditions. Furthermore, 
EPA maintains broad discretion to adopt performance-based criteria 
based on a record of protectiveness in various state instances under 
the interpretation of section 4004(a) as requiring a baseline standard 
of protection without mandating uniformity in the manner of attaining 
that baseline standard. Therefore, the Agency is proposing to adopt two 
provisions. These provisions would allow a permit authority (either the 
Participating State Director or EPA), to establish alternative 
groundwater protection standards, based on specific criteria, for 
constituents for which federal MCLs have not been established under the 
regulations referenced at Sec.  257.95(h)(1) (i.e., Sec. Sec.  141.62 
and 141.66) and to consider additional factors when establishing these 
standards. This proposal has one key change from the 2010 CCR Proposed 
Rule: the proposed language now allows the permit authority to make a 
determination on whether to allow alternative groundwater protection 
standards based on a set of criteria and factors, rather than relying 
solely on certification by a qualified professional certification. The 
alternative groundwater protection standards would have to be 
appropriate health-based levels that satisfy the following criteria:
     The level is derived in a manner consistent with Agency 
guidelines for assessing the health risks of environmental pollutants. 
For example, 51 FR 34006, Supplementary Guidance for Conducting Health 
Risk Assessment of Chemical Mixtures,\38\ which supplements 51 FR 
34014; the Guidelines for Developmental Toxicity Risk Assessment,\39\ 
which amends 51 FR 34028; and the Guidelines for Carcinogen Risk 
Assessment,\40\ which amends 51 FR 33992;
---------------------------------------------------------------------------

    \38\ USEPA, ``Supplementary Guidance for Conducting Health Risk 
Assessment of Chemical Mixtures'', EPA/630/R-00/002, August 2000.
    \39\ USEPA, ``Guidelines for Developmental Toxicity Risk 
Assessment'', EPA/600/FR-91/001, December 1991.
    \40\ USEPA, ``Guidelines for Carcinogen Risk Assessment'', EPA/
630/P-03/001F, March 2005.
---------------------------------------------------------------------------

     For carcinogens, the level represents a concentration 
associated with an excess lifetime cancer risk level (due to continuous 
lifetime exposure) within the 1 x 10-4 to 1 x 
10-6 range; and
     For systemic toxicants, the level represents a 
concentration to which the human population (including sensitive 
subgroups) could be exposed to on a daily basis that is likely to be 
without appreciable risk of deleterious effects during a lifetime. For 
purposes of this subpart, systemic toxicants include toxic chemicals 
that cause effects other than cancer or mutation.
    In establishing the alternative groundwater protection standards, 
the permit authority must consider the following:
     The presence and concentrations of other contaminants in 
the groundwater;
     Exposure threats to sensitive environmental receptors; and
     Other site-specific exposure or potential exposure to 
groundwater.
    EPA solicits comments on the criteria and factors that should be 
considered when establishing an alternative groundwater protection 
standard for constituents without established federal MCLs in the 
regulations referenced at Sec.  257.95(h)(1) (i.e., Sec. Sec.  141.62 
and 141.66). Additionally, EPA seeks input on any different approaches 
for determining these alternative groundwater protection standards and 
their merits. Specifically, EPA requests examples of state programs 
that utilize alternative groundwater protection standards and the 
methods, authority, and implementation of those programs.
2. Closure and Post-Closure Care Requirements
    EPA is proposing to codify permit flexibilities for units 
undergoing closure or post-closure care under a federal or 
participating-State CCR permit. These revisions would allow the 
Participating State Director or EPA, when serving as the permit 
authority, to assess an owner or operator's closure plan and approve a 
unit closure that deviates from the existing standards in Sec.  
257.102(c) and (d) when the permit authority determines that the 
planned closure will have no reasonable probability of adverse effects 
to human health and the environment during the active life of the CCR 
unit and the post-closure care period. Additionally, EPA is proposing 
to allow the permit authority to extend closure timeframes for CCR 
units where CCR is being extracted from the unit for beneficial use 
during closure. EPA is also soliciting comment on whether to adopt an 
outstanding proposal from 2018 that would allow a permit authority to 
establish an alternative post-closure care period under certain 
conditions. Lastly, EPA is proposing to allow a permit authority to 
permit the disruption of the cap during the post-closure care period, 
commonly referred to as ``unzipping'' the cap, to provide access for 
the extraction of CCR for beneficial use.
a. Closure Method
    In the 2015 CCR Rule, EPA finalized closure performance standards 
for two methods of closure, closure by removal of CCR from the unit and 
closure with CCR in place. Under Sec.  257.102(c), closure by removal 
is considered complete when CCR has been removed; any areas affected by 
the releases from the CCR unit have been removed or decontaminated; and 
groundwater monitoring concentrations of the constituents listed in 
appendix IV of part 257 do not exceed groundwater protection standards 
established pursuant to Sec.  257.95(h). The rule specifies that 
removal and decontamination activities include removing all CCR from 
the unit, CCR mixed with soils, and CCR included in berms, liners, or 
other unit structures, and removing or decontaminating all areas 
affected by releases from the CCR unit.
    For an owner or operator to close a CCR unit in place, the closure 
performance standards in Sec.  257.102(d) must be met. These closure 
performance standards require that the unit is closed in a manner that 
will: (1) Control, minimize, or eliminate, to the maximum extent 
feasible, post-closure infiltration of liquids into the waste and 
releases of CCR, leachate, or contaminated run-off to the ground or 
surface waters or to the atmosphere; (2) Preclude the probability of 
future impoundment of water, sediment, or slurry; (3) Include measures 
that provide for major slope stability to prevent the sloughing or 
movement of the final cover system during the closure and post-closure 
care period; and (4) Be completed in the shortest amount of time 
consistent with recognized and generally accepted good engineering 
practices. Additionally, Sec.  257.102(d)(2)(i) requires that free 
liquids must be eliminated by removing

[[Page 19003]]

liquid wastes or solidifying the remaining wastes and waste residues.
    Free liquids is currently defined as ``liquids that readily 
separate from the solid portion of a waste under ambient temperature 
and pressure.'' This definition has resulted in significant comments 
from regulated entities, stating the definition is overly stringent and 
unnecessarily complicated. Commenters pointed to other EPA programs, 
such as RCRA subtitle C, claiming that facilities may close their units 
in place, fully saturated, provided the units do not release free 
liquids.
    As discussed in Unit III.D. of this preamble, following publication 
of the Legacy Final Rule, EPA received many comments from members of 
industry on the risk assessment and risk associated with CCR units. 
Berkshire Hathaway (BH) notes that EPA's risk assessments ignore 
differences in regional and site-specific risk profiles. Instead of 
relying on a generic national-scale assessment, BH urged EPA to allow 
regulated facilities to submit individual risk assessments. USWAG 
stated in their comments on the Legacy Final Rule that ``the importance 
of risk assessment in the rule development process under RCRA cannot be 
overstated. A risk assessment, when properly done, identifies the 
specific risks potentially posed by a disposal practice and estimates 
the magnitude of those risks.'' In their January 2025 letter to EPA 
Administrator Lee Zeldin, USWAG states, ``the Rule could be vastly 
improved by moving away from one-size-fits-all self-implementing 
program to one that provides certainty through the issuance of permits 
and allows decisions to be made on risk and site-specific conditions.''
    As described later in this section and in Unit IV.A.2. of this 
preamble, members of industry have identified cases in which state 
regulators approved the closure of CCR units after an evaluation of 
risk determined there were no unacceptable risks or threats to 
downstream receptors. Therefore, EPA is proposing to allow the permit 
authority to approve closures that vary from the existing performance 
criteria in Sec.  257.102, based on site-specific considerations and 
criteria, to ensure facilities with complex challenges can close using 
tailored technical requirements that differ from the 2015 CCR Rule, 
while not posing a reasonable probability of adverse effects to human 
health and the environment. As stated in Unit III.D. of this preamble, 
the existing regulations were developed under a self-implementing 
framework with no oversight mechanisms to ensure site-specific 
modifications would be protective and technically appropriate. As a 
result, EPA did not include alternatives available in other programs 
under RCRA or CERCLA, which establish standards allowing a permit 
authority to tailor the baseline requirements for site-specific 
conditions. With the establishment of CCR permitting programs run by 
EPA or participating States, EPA is proposing to provide the 
opportunity for permit authorities to allow adjustments to the 
technical requirements of the 2015 CCR Rule that incorporate site-
specific factors. As discussed in Units III.D. and IV.B. of this 
preamble and described next regarding the use of conceptual site 
models, the ability for regulatory oversight through permit issuance 
and enforcement enables EPA to create another compliance pathway to 
meet the RCRA protectiveness standard utilizing adjusted requirements 
tailored to the site-specific risks presented by each CCR unit.
    Under the proposed flexibility to the closure standard, the permit 
authority may evaluate and approve a closure that differs from the 
requirements in Sec.  257.102(c) or (d), based on a determination that 
the alternative closure achieves the standard of no reasonable 
probability of adverse effects to human health and the environment. 
Under this alternative, the permit authority's approval must be based 
on a site-specific conceptual site model (CSM) and risk assessment of 
the facility area in which the CCR unit is located. This assessment 
must include the following: field collected measurements, aquifer 
characteristics, waste characteristics, climatic conditions, leachate 
characteristics, engineered controls, fate and transport predictions, 
exposure pathways, and downgradient receptors.
    CSMs are excellent tools to achieve, communicate, and maintain 
consensus between project partners. They are widely used throughout EPA 
programs such as Superfund, RCRA subtitle C, and subtitle D. A CSM is 
an iterative, `living representation' of a site that summarizes and 
helps all parties understand available information. A CSM uses a 
concise combination of written and graphical work products to portray 
both known and hypothesized site information. Using CSMs is considered 
a best management practice for technical effectiveness and resource 
efficiency. To properly quantify and understand potential risk from a 
CCR unit, site-specific criteria would be required to be included 
within the creation and evolution of a CSM.
    When working through the information to understand a unit, it is 
helpful to initially take a step back and look at the regional and 
locational geography and topography of an area to establish a 
foundation of understanding. However, EPA is proposing to require a CCR 
unit's CSM to have site-specific data to build off the initial 
foundation. Therefore, adequate characterization via field collected 
measurements must be utilized for the creation of a unit's CSM. Field 
measurements to understand the subsurface geology and stratigraphy are 
essential to understanding the subsurface forces at play within and 
below a CCR unit. Groundwater elevation, groundwater discharge and 
recharge, hydraulic conductivity, hydraulic gradient, effective 
porosity, and degree of saturation build the CSM to inform and define 
the aquifer(s). When looking at hydrogeology, it is imperative to not 
assume aquifer homogeneity. Many aquifers are heterogeneous and vary 
over lateral and vertical distance. Without a good understanding of the 
features such as degree of fracturing, secondary porosity, and 
geochemistry of the soils and bedrock, obtaining an accurate 
determination of fate and transport pathways to downgradient receptors 
is unlikely. Many times, these features and their characteristics are 
what provide the preferential pathways for the constituents listed in 
appendix III and IV of part 257. Innovative sampling or surveying may 
be useful for facilities with large CCR units or deep aquifers. 
Geophysical surveying can provide expenditure relief, but it is 
essential that the assumptions made during such surveys are 
corroborated with field hydrogeologic data.
    In building the CSM, after the foundation and understanding of the 
subsurface is established, the evaluation and inclusion of the 
emplaced, or disposed material would need to be evaluated to understand 
the potential impacts that material may have on the surrounding 
environment. It is known that CCR consists of multiple types of 
material of varying characteristics. As an example, fly ash tends to 
have a much smaller grain size than bottom ash. Lower permeability 
materials, such as fly ash, will likely hold onto liquid, because of 
this common property of fly ash, members of industry have mentioned 
that it is very difficult to entirely dewater units. For example, in 
their White Paper--Recommendations for Updating the Federal Coal 
Combustion (CCR) Regulations, CCIG mentions a member who is closing a 
large impoundment. While the member has been dewatering the unit to 
provide a stable subgrade for final closure

[[Page 19004]]

construction, the fine-grained CCR materials yield water very slowly, 
making it impossible to remove all liquid prior to placing the cover 
system within the closure timeframe allowed under the existing 
regulations. CCIG urged EPA to revise the performance standards to 
account for practical and risk considerations. EPA understands that for 
older facilities, it may be difficult to know exactly what was emplaced 
and when. This criteria of the waste emplaced and its characteristics, 
such as composition, solubility, density, the presence of immiscible 
constituents, Eh and pH, must be evaluated, when feasible, as it 
provides information on how the CCR will interact with the surrounding 
environment.
    After establishing an understanding of the regional area, site-
specific hydrogeology, and emplaced CCR, the owner or operators should 
incorporate into the CSM any additional engineered controls that are 
currently ongoing at the site as these controls impact the surrounding 
and subsurface forces at play. One of the most common engineered 
controls that we see at CCR units is the cap or cover of the unit. If 
CCR is left in place, a final cover must be installed within the 
appropriate timeframe. In accordance with the existing regulations, a 
description of the final cover and the procedures to be used to install 
the final cover must be provided in the unit's closure plan. The owner 
or operator must also ensure the design of the final cover system meets 
the performance standards specified in the regulation. The final cover 
system must be designed to have a permeability less than or equal to 
the permeability of any bottom liner system or the natural subsoils 
present, or a permeability no greater than 1 x 10-5 
centimeters per second (cm/sec), whichever is less.
    Since the promulgation of the 2015 CCR Final Rule EPA has received 
inquiries about the potential of alternative covers, specifically 
regarding engineered turf covers. EPA reviewed documentation on the 
components and performance of engineered turf as a final cover system 
and considers it to be sufficient if it meets the performance standards 
in the regulation. Engineered turf as a final cover consists of a 
three-component system: a structured geomembrane, engineered turf, and 
specified infill. The structured geomembrane layer acts as a barrier 
layer minimizing, or more ideally eliminating, infiltration while also 
providing a drainage layer to minimize hydraulic head on the liner. The 
engineered turf portion provides protection from UV degradation and 
soil erosion. The specified infill layer provides a protection layer, 
both covering and underlying the geotextile backing and geomembrane 
from UV degradation. It additionally provides protection from wind 
uplift and protects the turf from fire. Documentation on engineered 
turf provided to the Agency identified that under the Hydrologic 
Evaluation of Landfill Performance (HELP) model, engineered turf 
outperforms prescriptive subtitle D-required covers with geocomposite 
drainage by an order of magnitude. That being said, it is imperative 
for the owner or operator to demonstrate the final cover system, even 
if engineered turf, meets the required performance standards and the 
permit authority must concur with the findings.
    Additional engineered examples that should be evaluated and 
included in the CSM can range from pump-and-treat systems to barrier 
walls, and other remedial infrastructures. For example, if a unit is in 
corrective action and has an operating pump-and-treat system to capture 
the plume of an appendix IV constituent, the redirection or impact on 
the local groundwater may change previous understandings of 
preferential pathways or exposure pathways. It is important to 
understand the purpose and impact engineered control(s) have on a unit, 
and its intended lifespan and what were to happen if and when the 
engineered control(s) were to be removed. Contaminant fate and 
transport groundwater modeling is a common tool that can be utilized to 
understand an area, it's subsurface, and what influences and impacts an 
environment. For contaminant fate and transport or even a more 
simplistic groundwater flow model to be effective, it must have site-
specific information imbedded in the model.
    As a living representation, CSMs are not intended to be a one-and-
done administrative task, rather they are an opportunity to take what 
we know of a unit, expand our knowledge, and ground-truth the 
information we have. It is a best practice to update CSMs as new 
information is obtained that improves our understanding of a facility 
or a unit. If a unit is not properly characterized, the CSM will be 
limited, data gaps will likely cause challenges down the line that 
ultimately led to higher expenditure for closure or remediation.
    The second part of the assessment consists of a risk assessment. As 
mentioned above in this section and in Unit IV.A.2., members from 
industry have informed EPA that they have units previously closed in 
place, under state oversight, based on a determination of no 
unacceptable risk. As described in Unit III.D. of this proposal, the 
2014 and 2024 Risk Assessments are based on high-end exposure levels. 
Many in the regulated community have stated that the one-size-fits-all 
solution does not accurately relate to their facilities and units and 
that a site-specific risk assessment should be allowed to provide 
flexibility and address challenges faced in the closure process. This 
is especially expressed by those in the regulated community that have 
previously closed their CCR unit under state oversight that required a 
risk assessment and state concurrence with any conclusion of no 
unacceptable risk to human health and the environment.
    As noted in Unit IV.B. above, the majority of state and industry 
commenters on the proposal that resulted in the 2015 CCR rule preferred 
regulations that would allow site-specific approaches to establishing 
standards (See 80 FR 21331-21234). Commenters argued that the 
prescriptive one-size-fits-all approach was overly stringent and 
inflexible and had the potential to greatly disrupt implementation of a 
state's regulatory programs, which have been tailored to provide for 
site specific conditions and situations. As described in Unit III.D., 
EPA acknowledges that the CCR universe includes a variety of sites and 
site conditions and therefore, no single site can represent all 
regulated facilities. An example highlighting the uniqueness of sites 
and the need for site-specific approaches is Georgia Power's Grumman 
Road CCR Unit, located in Chatham County. This unit is owned and 
operated by Georgia Power and previously used for the disposal of CCR 
for Georgia Power's Plant Kraft. Additionally, all ongoing work on and 
related to this unit is overseen and regulated by the Georgia 
Environmental Protection Division (EPD). The unit being discussed here 
is separate to the unit previously discussed in Unit IV.A.2. of this 
preamble discussing the Kraft Legacy CCR unit closed under Georgia's 
Voluntary Remediation Program. The unit was retired in late 2015 and is 
regulated under the Federal Rule and Georgia's Solid Waste Management 
CCR Regulations 391-3-4.10.
    The Grumman Road CCR unit has a monitoring well system, with 
lateral well spacings ranging from approximately 230 feet to 414 feet, 
with an average lateral well spacing on the order of 324 feet. This 
well network has been established for both detection and assessment 
monitoring of appendix III and appendix IV constituents. This unit has 
undergone many iterations of its CSM, with each revision growing in 
specificity to understand the

[[Page 19005]]

interworking of not only the immediate subsurface of the unit, but also 
the surrounding environmental and anthropogenic factors impacting the 
unit. Over the years, Georgia Power has worked alongside Georgia EPD, a 
State with a partially approved CCR program, to further develop the 
unit's CSM. Additionally, via fieldwork, sampling and bench tests, 
Georgia Power has developed many iterations of Hydrogeological 
Assessment Reports under the oversight of the state.
    As mentioned earlier, a robust site-specific characterization is 
key in understanding any site including the surrounding environment in 
which it is located. The permit drawings of the Grumman Road CCR unit 
identify a small percentage of saturation for the southern portion of 
the unit, which is likely in contact with groundwater year-round. 
According to Georgia Power, another site-specific factor that 
influences decision making for this unit, are anthropogenic impacts 
from an adjacent landfill's release of leachate. Georgia Power states 
that the adjacent landfill's seep impacts the Grumman Road CCR Unit by 
changing the redox conditions of the aquifer, which is inducing 
mobilization of arsenic and molybdenum as dissolved constituents in 
groundwater. Such characterization details must be understood in order 
to evaluate releases from the CCR unit in the context of background and 
other factors. This does not change the fact that Grumman Road has an 
ongoing release and that it must be addressed via corrective action. In 
coordination with Georgia EPD, Georgia Power initiated an Assessment of 
Corrective Measures program for Grumman Road in December 2020.
    As part of the Assessment of Corrective Measures, Georgia Power 
conducted a Risk Evaluation, which can be found in appendix B of the 
Remedy Selection Report. The provided report relies on risk approaches 
outlined in Georgia's Voluntary Remediation Program with components of 
the Risk Assessment Guidance for Superfund (RAGS). The Risk Evaluation 
considered potential transport pathways, exposure pathways, and both 
current and future receptors. Georgia Power reviewed the concentrations 
and statistics for wells of the unit, individually. Additionally, 
Georgia Power conducted modeling to estimate the current areal extent 
of the plume. Georgia Power concluded in their risk evaluation that the 
SSL-related constituents arsenic and molybdenum are not expected to 
pose a risk to human health or the environment.
    It is understood that remedial investigations, feasibility studies, 
determinations of the most effective remedial technologies and 
implementation of those technologies take time. Additionally, there is 
the time for the remedial technology to influence, reduce, or eliminate 
source zones, which will in turn, impact whatever risk(s) may be 
present at a site. According to Georgia Power, the lack of immediate 
exposure allows for the comprehensive evaluation of remedial 
technologies and a deeper understanding of the geochemistry of the 
subsurface. This is detailed in Georgia Power's Assessment of 
Corrective Measures Report Appendix A, the Geochemical Site Model. 
While this site is still undergoing corrective action, it supports the 
use of regulatory flexibility based on site-specific information and 
risk evaluations. Aquifer geochemistry, anthropogenic impacts, and 
other site-specific conditions cannot be generically applied across all 
sites, which is why a robust CSM is critical for the purposes of 
decision-making. It is important to note that EPA recognizes that a 
remedy has not yet been selected and additional work is necessary in 
order to complete corrective action.
    In another example, the state of Tennessee and its Department of 
Environment and Conservation (TDEC) issue a Commissioner's Order to TVA 
at seven coal-fired power plant facilities. This Order required TVA to 
conduct environmental investigations and assessments for all CCR 
disposal areas. One of the required deliverables from the Order was a 
risk assessment, to be included in the Corrective Action/Risk 
Assessment (CARA) Plan. TVA submitted a CARA for the Allen Fossil Plant 
West Ash Disposal Area, which according to TVA, was found to be 
acceptable by TDEC. This can be found on both TDEC's website, TVA's 
public website, and within docket of this proposal. TVA presented their 
findings from their Draft CARA for the John Sevier Fossil Plant to 
identify current challenges with the Rule. The John Sevier Draft CARA 
contained a CSM of the site and a risk assessment that evaluated risk 
both for human health and ecological risks.
    Under this proposal, if Tennessee were to apply for CCR permit 
program, and if the program is ultimately approved, TDEC could approve 
TVA's proposed closure (i.e., authorize TVA to close with saturated CCR 
in place), if TDEC concluded, based on an evaluation of the CARA, that 
the proposed closure does not pose a reasonable probability of adverse 
effects to human health or the environment based on the criteria set 
forth in this proposed regulation. EPA expects the permit authority to 
ensure all current and future human and ecological receptors are 
considered within the risk assessment and CSM. This would require the 
owner or operator to evaluate all current and any future planned land 
use, identify receptors, and exposure routes. If corrective action is 
ongoing or an engineered control is onsite, the potential risk should 
be evaluated if or when the acting life of the engineered control or 
corrective action is ceased.
    Another example supporting this flexibility was provided by Vistra 
Corp. Vistra had a CCR unit that was taken out of service in 1996 and 
has been subject to groundwater sampling since that time. The utility 
closed the unit pursuant to state approval. Standing water was removed, 
and a final cover system was installed pursuant to the federal CCR Rule 
in 2020. The final cover consisted of a compacted soil barrier clay 
layer with a minimum of 24 inches of earthen material with a maximum 
permeability of 1 x 10-7 cm/s. According to Vistra, in 
limited areas, ash may be saturated with groundwater during higher 
flood events. While an exceedance of an appendix III constituent has 
been detected, the company states that the data demonstrates that 
simply dewatering and taking the unit offline resulted in significant 
decreasing trends of the appendix III constituent, with some wells now 
achieving compliance with the groundwater protection standard. Under 
this proposal, once the state's CCR permit program was approved, the 
state could approve the closure described above, if the state 
determined the closure posed no reasonable probability of adverse 
effects to health or the environment after conducting a review as 
discussed above.
    A final example of the need for this flexibility is the East Ash 
Basin at Duke Energy's Roxboro Steam Electric Plant in North Carolina. 
During and after the Legacy Rulemaking, Duke provided information to 
EPA on past, present, and future activities at their facilities 
conducted under the oversight of the NCDEQ and pursuant to the 2020 
Consent Order and under the oversight of North Carolina's CCR program. 
According to Duke Energy, there are two CCR surface impoundments at the 
Roxboro facility, the East Ash Basin and the West Ash Basin, and a CCR 
landfill, the Industrial Landfill. Neither of the impoundments receive 
CCR wastestreams anymore. The Industrial Landfill receives CCR from 
electrical production and for CCR consolidation from other CCR units at 
the facility. The

[[Page 19006]]

East Ash Basin was approximately 71 acres and contained approximately 
7.1 million tons of CCR. The Industrial Landfill was constructed 
partially atop and adjacent to the East Ash Basin and is approximately 
132 acres in size.
    Duke Energy submitted a closure plan to NDEQ by the December 31, 
2019 deadline set by the 2016 CAMA and in accordance with a 2019 
settlement agreement between Duke and NCDEQ. NCDEQ subsequently 
approved the closure plan which included excavating approximately 15.4 
million tons of CCR from surface impoundments at Roxboro. The closure 
plan also allowed the East Ash Basin to close with some saturated ash 
remaining in the unit underneath the overlying Industrial Landfill. 
According to Duke Energy, closure of the surface impoundments, under 
the oversight of NCDEQ, is ongoing at the facility with a completion 
deadline of December 2036, pursuant to the 2020 Consent Order. The 
primary activities are source removal and capping measures, with 
1,116,988 tons of ash and soil excavated from the East Ash Basin and 
4,153,402 tons from the West Ash Basin as of July 2025.
    Duke submitted the Roxboro East Ash Basin Corrective Action Plan 
(CAP) to NCDEQ in December 2019 in accordance with CAMA. NCDEQ 
conditionally approved the CAP in April 2021. A pilot testing phase 
began in November 2021, followed by the full-scale system start-up in 
January 2023. Under the 2020 Consent Order which applies to the Roxboro 
surface impoundments among other surface impoundments in the state, 
groundwater standards for constituents of interest must be met by 
December 31, 2029, at the geographic limitation, 500 feet downgradient 
of the waste boundary. Pursuant to the conditions of the 2020 Consent 
Order, groundwater modeling updates are required every three years, 
with the first update submitted to NCDEQ in September 2023. The CAP 
system includes a pump-and-treat-system consisting of 41 extraction 
wells, 3 node boxes, and 29,390 linear feet of piping and an engineered 
liner on top of the East Ash Basin was installed to control 
contamination coming from the unit. According to Duke, the system's 
average flow rate decreased from 108 gallons per minute (gpm) to 80 gpm 
due to bedrock dewatering. Extracted water is treated before discharge 
through a permitted NPDES outfall. Duke has stated that hydraulic 
gradient reversal is occurring at the facility and thus prevents 
constituents of interest migration toward surface water receptors, 
ensuring no unacceptable risks to human health or the environment. The 
utility has provided data that it claims demonstrates that groundwater 
quality around the East Ash Basin has improved significantly, with 62 
percent of all constituents of interest and 83 percent of primary 
constituents meeting compliance standards at or beyond the geographic 
limitation as of the fourth quarter of 2024. Duke contends that the 
high boron concentrations are attributed to non-ash basin sources, and 
trends show decreasing or stable levels for most constituents of 
interest.
    Duke points to the CAP data, the risk assessment required under 
CAMA, the oversight of NCDEQ and the permanent alternative water 
sources that have been provided to nearby residents as a precautionary 
measure, as evidence that the closure of the East Ash Basin is 
protective of human health and the environment and as an example of 
both the need for site-specific considerations, especially with regard 
to closure, and the sufficiency of state-led compliance activities.
    The NCDEQ-approved closure of the East Ash Basin would not meet the 
current federal CCR closure requirements; for example, the requirement 
to remove all free liquids prior to installing the final cover system. 
Under this proposal, the permit authority (either the state's CCR 
permit program once it was approved or the federal CCR permit program) 
could evaluate the NCDEQ closure and conclude the closure poses no 
reasonable probability of adverse effects to health or the environment 
and no further closure activities are required to comply with the 
federal CCR closure requirements.
    As described in Unit III.D. of this preamble, such a site-specific 
determination was not available under the 2015 CCR Rule as EPA lacked 
permitting and enforcement authority. Now with the new tools provided 
by the WIIN Act, and EPA's broad discretion to adopt performance-based 
criteria based on a record of protectiveness, enable EPA to adopt 
provisions that create another pathway for compliance with the federal 
CCR regulations. Specifically, this provision would allow EPA or a 
participating-state permit authority to establish alternative closure 
requirements through the permitting process based on site-specific 
information.
    Solicitation of comment. Although the current proposal applies 
exclusively to closure, many of the same issues were raised in the 
context of corrective action. EPA is therefore soliciting comment on 
whether to expand this provision to allow a permit authority to approve 
corrective action remedies that do not meet the requirements of Sec.  
257.97(b) based on the results of a site-specific risk assessment that 
meets the criteria discussed above. EPA is also soliciting comment on 
what, if any, change in burden the proposed provision or the expansion 
of the proposed provision to corrective action would have on state 
permitting authorities.
    EPA is also soliciting comment on a provision in 85 FR 12456, which 
was proposed on March 3, 2020. In this 2020 proposal, EPA proposed to 
allow the use of CCR during the closure of a unit subject to closure 
for cause if such placement is conducted under an approved closure 
plan. The 2020 proposed alternative would be implemented as an 
exemption to the waste placement prohibition. It is unclear if this 
2020 proposal should be finalized, as the new proposed permitting 
closure flexibility of closure would allow the permit authority to make 
site-specific determinations to allow for this utilization of CCR 
during closure. Therefore, EPA is soliciting comment on whether this 
provision should be finalized as proposed under the first option in the 
2020 proposed rule.
    Finally, EPA is soliciting comment on an alternative provision that 
would provide flexibility regarding the drainage and stabilization 
requirements for CCR units closing with waste in place at Sec.  
257.102(d)(2)(i). Under this alternative provision, owners or operators 
could close a unit with saturated CCR in place if a permit authority 
has determined that certain conditions were met. In order to obtain 
this flexibility, the permit authority must evaluate the closure plan 
and ensure the following: (1) To promote the workability and stability 
of the final cover for the CCR unit, standing liquid and sufficient 
subsurface liquid has been eliminated; (2) The hydraulic condition 
within the CCR unit will not adversely impact the stability of the 
final cover system or the ability for the remaining wastes to support 
the final cover system; (3) The hydraulic condition within the CCR unit 
will not adversely impact the ability to implement any corrective 
action(s) necessary to meet the requirements of Sec. Sec.  257.96-
257.98; and (4) The hydraulic condition within the CCR unit will not 
result in a reasonable probability of adverse effects to human health 
and ecological receptors as determined through a site-specific 
assessment that evaluates all potential exposure pathways. If the 
permit authority determines that all these conditions

[[Page 19007]]

have been met, the owner or operator can close with CCR in place in 
accordance with the provisions in Sec.  257.102(d) aside from the 
requirement at Sec.  257.102(d)(2)(i) (i.e., any liquids remaining in 
the CCR unit need not be removed).
b. Closure Timeframes for CCR Units Extracting CCR for Beneficial Use 
During Closure
    EPA is proposing to allow the permit authority to extend closure 
timeframes for CCR units where CCR is being extracted from the unit for 
beneficial use during closure. In the 2015 CCR Rule, EPA finalized 
closure timeframes that adopted the approach recommended by commenters 
of tiered timeframes based primarily on size of the surface 
impoundment, and the concept of a rebuttable presumption that the owner 
and operator of a CCR surface impoundment must complete closure of the 
CCR unit within five years of initiating closure activities. For CCR 
landfills, the owner or operator of the unit must normally complete 
closure within six months of initiating closure activities.
    When reviewing comments on the 2010 CCR Proposed Rule regarding the 
closure timeframes and potential extensions, many of the regulated 
community identified concerns regarding the challenges in estimating 
closure timeframes. As a response, with the provided record at that 
time, EPA established a tiered approach for closure timeframe 
extensions which could be applied under the self-implementing 
regulatory framework.
    The tiered approach adopted for the 2015 CCR Rule allows CCR 
surface impoundments additional time dependent on size of the unit, 
using surface area acreage of the CCR as the determining factor for 
defining the size of the unit. Smaller impoundments, defined as 40 
acres or less have the maximum extension time of two years. 
Impoundments larger than 40 acres are allowed a maximum of five two-
year extensions, with the requirement that the owner or operator must 
substantiate the factual circumstances demonstrating the need for each 
two-year extension. Closure extensions for CCR landfills do not vary 
dependent on size. Rather, all CCR landfills are allowed the maximum of 
two one-year extensions. Similarly to surface impoundment units, the 
owner or operator of the CCR landfill document the factual 
circumstances demonstrating the need for each one-year extension. The 
documentation must include the exact reason why additional time is 
needed. The regulation includes examples such as: complications 
stemming from climate and weather, time required to dewater a surface 
impoundment due to the volume of CCR or the CCR geotechnical 
characteristics, the geology and terrain surrounding the CCR, and the 
time required or delays caused by the need to obtain state permits or 
to comply with other state requirements.
    With the record provided, EPA determined in the 2015 CCR Final Rule 
that the initial timeframes would be sufficient to close most, if not 
all CCR units and therefore, the extensions would accommodate for any 
potential delays caused by weather or other instances designated as 
``force majeure.'' However, uncertainties within the provided record 
were identified and documented in the 2015 CCR Rule such as: the Agency 
mentioned it had no information on the geotechnical properties of the 
CCR that can affect the time needed to dewater a unit, the volumes of 
clays, soils, and other materials that would be needed for closure, and 
the information on the time to obtain state approvals. Further, EPA 
stated in the preamble that the level of uncertainty increases with 
impoundments larger than 40 acres. Some documentation in the record 
indicates that closure for units larger than 40 acres can be closed 
within the same timeframe but other case studies provided stated that 
closure was expected to take much longer than five years.
    The Legacy Final Rule revised the closure timeframes set forth in 
the 2015 CCR Rule for owners or operators of landfills that were 
identified as having CCR in contact with groundwater and therefore, 
needed additional time to dewater the unit. The amount of time 
extended, similarly to surface impoundments, was dependent on the 
acreage of the landfill. Therefore, a landfill in this situation less 
than 40 acres may receive a maximum extension of two years and those 
greater than 40 acres may receive a maximum extension of 10 years, in 
two-year increments. Similarly to the provisions in the 2015 CCR Rule, 
documentation of the need for this extra time must be documented.
    Commenters of the 2015 CCR Rule recommended another approach of 
allowing closure timeframes to be governed by an adequate state-
approved closure process. In the 2015 Final Rule, EPA identified that 
under a self-implementing program, the Agency cannot rely on the 
existence of the state permit authority to implement subtitle D 
requirements. With the enactment of the WIIN Act, EPA now has ``new 
tools'' to achieve its regulatory goals, namely the authority to issue 
permits, enforce the regulations, and approve state CCR permit 
programs; with the oversight mechanisms provided by the ``new tools'' a 
permit authority is able to implement the criteria to ensure an 
extended closure timeframe still meets the required standard of no 
reasonable probability of adverse effects on health or the environment.
    Since promulgation of the 2015 CCR Rule, states and members of the 
regulated community expressed concern or have provided EPA with 
information to demonstrate the infeasibility of the existing closure 
timeframes for CCR units who wish to excavate CCR for beneficial use 
during closure. For example, TVA stated that certain units could not 
complete extraction of CCR for beneficial use within the current 
closure deadlines. To support this claim, TVA pointed to larger volume 
units, units that start CCR extractions partway through the closure 
process, or units that have already completed closure.
    Further, PacifiCorp has expressed concern that the existing CCR 
regulations do not provide sufficient time for closure by removal. 
According to PacifiCorp, the extension process and the maximum 
timeframe may still be inadequate to maximize excavation and beneficial 
use opportunities. PacifiCorp requested that EPA consider not requiring 
multiple timeline extension demonstrations for closure that involve 
extraction of CCR for beneficial use, provided that the initial 
extension schedule is appropriately supported by extraction and 
beneficial use contracts. In their request, it was suggested that 
industry could provide regular updates in the form of annual progress 
reports. By having the flexibility, PacifiCorp maintained that it would 
ultimately enhance environmental protection through source removal.
    As another example, Talen Energy stated that there are challenges 
in finding a beneficial use provider capable of accepting millions of 
tons of CCR over many years. Further, the utility has claimed that 
removing, loading, and hauling of millions of tons of CCR from a single 
source and within the current timeframes is not always possible. 
According to Talen Energy, there are several conditions that pose 
challenges to meeting the existing deadlines when closing by removal 
with CCR extraction for beneficial use as a component, such as: lack of 
onsite space to build a new landfill, or available landfill capacity; 
local road impacts, due to the amount of trucks; bridge load 
restrictions; community opposition to increased truck traffic; demand 
for the end-product (e.g., cement) or raw

[[Page 19008]]

materials, which limits the rate of outgoing CCR; safety concerns with 
basin excavation and specialized CCR product handling; additional 
volumes of CCR identified during closure; and non-CCR material 
identification and disposal. Accordingly, the utility suggested that 
EPA allow for flexibility regarding the closure timeframes when 
extracting CCR for beneficial use from the closing CCR unit.
    Southern Company reached out to EPA to discuss their progress with 
projects involving the extraction of CCR for beneficial use. According 
to the company, all their extracted CCR is encapsulated in the form of 
either concrete block, as filler, or otherwise used in the cement or 
concrete manufacturing process. According to Southern Company, they 
have taken a market-driven approach to the extraction of CCR and strict 
adherence to the existing closure timeframe or certain closure 
activities could impact the ability of the CCR supply to continue to 
meet demand.
    In addition to industry, States have also requested flexibility. 
For example, Tennessee has requested that EPA consider adjusting 
timeframes for closure to allow for CCR extraction of beneficial use. 
Further, the Agency has received input from states requesting EPA allow 
flexibility with respect to determining timeframes.
    Recognizing these site-specific situations, and considering the new 
tools provided by the 2016 WIIN Act, EPA's ability to allow for non-
uniformity in achieving the RCRA protectiveness standard, and EPA's 
discretion to adopt performance-based criteria based on a record of 
protectiveness, EPA proposes to allow flexibility for permit 
authorities to authorize adequate time to complete extraction of CCR 
for beneficial use from CCR units undergoing closure. The proposed 
amendment would authorize a permit authority to review and approve 
closures that include as, a component of the overall closure method, 
extraction of CCR for beneficial use, only if the Director finds, based 
on specific criteria and a demonstration by the owner or operator, that 
there would be no reasonable probability of adverse effects on health 
or the environment.
    EPA is proposing to establish criteria for the closure flexibility 
assessment that will be conducted by the permit authority. Such an 
evaluation is unit-specific, so the permit application, which would 
include a detailed closure plan and any supporting documents such as 
detailed design drawings and schedules, must be adequate to support the 
evaluation. First, the permit authority must ensure measures for major 
slope stability are in place to prevent the sloughing or movement of 
the unit during the closure period. Second, the permit authority must 
determine the extraction of CCR and closure will be completed 
consistent with recognized and generally accepted good engineering 
practices. Third, the permit authority must consider whether all 
potential risks to human health and the environment during closure of 
the unit are adequately mitigated. Fourth, the permit authority must 
evaluate whether the facility is in substantial compliance with all 
other requirements of this subpart, including the requirement to 
conduct groundwater monitoring and any necessary corrective action. By 
ensuring that groundwater monitoring and corrective action activities 
continue throughout the extended closure timeframe, the permit 
authority will have the ability to require the facility to take action, 
if necessary, to ensure there will be no reasonable probability of 
adverse effects on health or the environment. Lastly, the owner or 
operator must proceed with closure activities of any portion of the CCR 
unit that is not related to the extraction of CCR for beneficial use 
within the existing timeframes in Sec.  257.102 to the extent possible. 
Under this approach, the permit authority could extend the closure 
timeframe for owners or operators of units during which extractions of 
CCR will occur during the closures. It is important to note that any 
extension of the final closure date will occur under conditions where 
the unit has groundwater monitoring in place and corrective action 
requirements will be triggered should a release be detected--these 
requirements can be relied upon by the permit authority in making its 
protectiveness determination.
    Solicitation of comment. The Agency is soliciting comment on 
whether to allow the permit authority to extend timeframes for all 
closures, regardless if the closure includes beneficial use activities. 
Additionally, the Agency requests comment if there should be a ``good 
cause'' condition, or whether there should be criteria to frame the 
discretion by the permit authority. Furthermore, EPA is requesting 
comment on specifying that the closure timeframe flexibility can also 
be applied to allow adequate time to complete extraction of CCR for 
critical mineral recovery activities. While the recovery of critical 
minerals from CCR is not a direct use of the CCR, it is a resource 
recovery activity (i.e., an activity supported by RCRA statutory 
provisions) that has the potential to play a crucial role in 
maintaining technological advancement, economic growth, and national 
security. Critical minerals are a group of elements and compounds that 
are essential in the production of modern technologies and industries. 
Examples of these minerals include lithium, cobalt, nickel, graphite, 
manganese, and rare earth elements such as neodymium, praseodymium, and 
dysprosium. Their unique properties, such as conductivity, magnetism, 
and strength, make them indispensable for various technological 
applications.
    The Department of Energy's National Laboratories have developed 
several technologies that focus on extracting critical minerals and 
rare earth elements from CCR. Each method has been tested at the lab 
scale and is ready for companies to further develop, refine, and scale 
into commercial systems.\41\ However, these technologies are still at 
an early stage in development, and there are several barriers to 
overcome before full-scale commercial critical mineral extraction 
activities are feasible. EPA requests comment on using closure and 
post-closure flexibilities as a way of encouraging the development of 
this industry, and requests information on any other regulatory 
barriers to developing environmentally protective processes for 
critical mineral extraction from CCR. Information on commercialization 
would be particularly helpful, including a projected timeline and the 
specific barriers yet to be addressed, such as environmental and 
economic factors. EPA also requests information on likely 
commercialization models with their logistics, such as planned location 
for recovery operations, (e.g., onsite at a utility or off-site at a 
regional center; types of activities necessary to prepare CCR for 
processing; expected amounts and management of CCR prior to critical 
minerals recovery; preferred technological processes to extract, purify 
and separate critical minerals; and residuals or wastes generated by 
the technologies, including the characteristics and the ultimate 
management of those wastes).
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    \41\ U.S. Department of Energy. A new chapter for coal: 
Commercialization opportunities at DOE labs. Retrieved November 12, 
2025, from https://www.energy.gov/technologycommercialization/articles/new-chapter-coal-commercialization-opportunities-doe-labs.
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c. Post-Closure Care Flexibility for Units Undergoing Extraction for 
Beneficial Reuse
    Following closure of a CCR unit, the owner or operator is required 
to conduct

[[Page 19009]]

post-closure care of any closed unit where CCR was left in place as 
part of closure. At a minimum, the owner or operator is required to 
comply with at least the following: (1) Maintain the integrity and 
effectiveness of any final cover system, including making repairs to 
the final cover as necessary to correct the effects of settlement, 
subsidence, erosion, or other events, and preventing run-on and run-off 
from eroding or otherwise damaging the final cover; (2) If the CCR unit 
is subject to the design criteria under Sec.  257.70, maintain the 
integrity and effectiveness of the leachate collection and removal 
system and operate the leachate collection and removal system in 
accordance with the requirements of Sec.  257.70; and (3) Maintain the 
groundwater monitoring system and monitoring the groundwater in 
accordance with the requirements of Sec. Sec.  257.90 through 257.98. 
See Sec.  257.104(b).
    Additionally, the existing CCR regulations identify the minimum 
information necessary to include in the post-closure care plan. This 
information includes: (1) A description of the monitoring and 
maintenance activities required by Sec.  257.104(b), and the frequency 
at which these activities would be performed; (2) The name, address, 
telephone number, and email address of the person or office to contact 
about the facility during the post-closure care period; and (3) A 
description of the planned uses of the property during the post-closure 
care period. The proposed rule further provided that the post-closure 
use of the property shall not disturb the integrity of the final cover, 
liner(s), or any other components of the containment system, or the 
function of the post-closure monitoring systems unless necessary to 
comply with the requirements of the rule. As written, the existing 
regulations at Sec.  257.104(d)(1)(iii) do allow for a disturbance if 
the owner or operator of the CCR unit can demonstrate that disturbance 
of the final cover, liner, or other component of the containment 
system, including any removal of CCR, would not increase the potential 
threat to human health or the environment. Such a demonstration is 
required to be certified by a qualified professional engineer or 
approved by the Participating State Director or EPA, where EPA is the 
permit authority. Additionally, a notification shall be provided to the 
State Director that the demonstration has been placed in the operating 
record and on the owners or operator's CCR website.
    Since promulgation of the 2015 CCR Rule, states and members of the 
regulated community expressed concern that the current regulations 
could be interpreted in such a way as to prevent extraction of CCR for 
beneficial use during the post-closure care period. Specifically, there 
is concern that the requirement to maintain a cap over the unit would 
prevent access to the material beneath the cap for beneficial use 
projects. Members of industry has asked for an allowance for disturbing 
the cap to provide such access, commonly referred to as ``unzipping''. 
The Agency maintains that under the existing rules, the owner or 
operator of the CCR unit has the ability to demonstrate that 
disturbance of the final cover, liner, or other component of the 
containment system, including any removal of CCR, would not increase 
the potential threat to human health or the environment. A qualified 
professional engineer is required to certify such a demonstration. See 
Sec.  257.104(d)(1)(iii). Nevertheless, to avoid any uncertainty EPA is 
proposing a new provision to explicitly allow a permit authority to 
have the flexibility to approve the extraction of CCR from a closed CCR 
unit during the post-closure care period under certain conditions. 
Under this approach, for extraction of CCR for beneficial use during 
the post-closure period, the permit authority may adjust the minimum 
criteria only if the authority finds, based on a demonstration by the 
owner or operator, that any extraction of CCR for beneficial use will 
not pose a reasonable probability of adverse effects to human health 
and the environment. In reaching this determination, the permit 
authority must conclude all of the following: the extraction of CCR 
will be completed consistent with recognized and generally accepted 
good engineering practices; potential risks to human health and the 
environment during post-closure are adequately mitigated; and the 
facility is in substantial compliance with all other requirements of 
this subpart, including the requirement to conduct post-closure care, 
groundwater monitoring and any necessary corrective action.
d. Modification of the Post-Closure Care Period
    The current regulations at Sec.  257.104(c)(1) state that the owner 
or operator of a closed CCR unit must conduct post-closure care for 30 
years unless at the end of the 30 years corrective action is on-going, 
or the CCR unit is operating under assessment monitoring, in which case 
the owner or operator must continue to conduct post-closure care until 
the unit has returned to detection monitoring.
    In 2018, following the enactment of the WIIN Act, EPA proposed to 
adopt a provision analogous to Sec.  258.61(b), that would allow the 
Director of a participating state to decrease the length of the post-
closure care period if the owner or operator demonstrates that the 
reduced period is sufficient to protect human health and the 
environment and this demonstration is approved by the Director. It also 
would allow the Director of the participating state to increase the 
length of the post closure period if the Director determines a 
lengthened period is necessary to protect human health and the 
environment. 83 FR 11584, 11603-604 (Hazardous and Solid Waste 
Management System: Disposal of Coal Combustion Residuals From Electric 
Utilities; Amendments to the National Minimum Criteria (Phase One)) 
EPA-HQ-OLEM-2017-0286; FRL-9973-31-OLEM).
    Due to competing priorities EPA did not finalize that proposal and 
it remains pending. EPA is now again soliciting comment on whether to 
adopt those proposals.

C. Beneficial Use

    EPA is proposing to revise the definition of beneficial use for CCR 
to recognize that the first three criteria in the beneficial use 
definition provide a sufficient framework for identifying when 
placement of CCR on the land, whether encapsulated or unencapsulated, 
roadway or non-roadway, constitutes a beneficial use rather than 
disposal under the RCRA statute. EPA is also proposing to remove the 
fourth criterion that currently requires that 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'' for unencapsulated non-roadway uses on the land 
above the threshold of 12,400 tons, finding that: (1) The 12,400 ton 
threshold is based on faulty information, (2) The demonstration 
requirement poses an unacceptable barrier to beneficial use, and (3) 
The fourth criterion is not needed to prevent disposal of 
unencapsulated CCR that would present a reasonable probability of 
adverse effects on health or the environment. This change in the 
Agency's position in regard to the regulation of unencapsulated non-

[[Page 19010]]

roadway CCR use is based on an analysis of past damage incidents and 
the most recent industry standards for CCR used as structural fill.
    EPA is also proposing new definitions of ``CCR storage pile'' and 
``temporary accumulation'' to establish a single set of requirements 
applicable to all temporary placement of unencapsulated CCR on the 
land, whether managed onsite or off-site, and whether destined for 
beneficial use or disposal. These new proposed definitions are similar 
to those proposed in 2019,\42\ with some adjustments to the previously 
proposed language to make the requirements clearer and less burdensome. 
EPA is also proposing to remove the definition of ``CCR pile'' found at 
Sec.  257.53 and instead address CCR accumulations that do not meet the 
definition of CCR storage pile directly in the definition of CCR 
landfill.
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    \42\ See 84 FR 40353, August 14, 2019.
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    In addition, recognizing the unique role CCR plays as an ingredient 
in cement manufacturing, EPA is proposing to add a provision at Sec.  
257.50(k) to exclude from the requirements of 40 CFR part 257 CCR at 
cement kilns that is destined for use as an ingredient in cement 
manufacturing. This proposed provision acknowledges the benefit CCR 
provides as an ingredient in cement manufacturing, and how this benefit 
incentivizes the management of CCR as a valuable commodity at the 
cement kiln and helps ensure it will be appropriately incorporated in 
an encapsulated beneficial use. EPA is also requesting comment on 
whether it would be helpful to include a regulatory clarification 
explaining that the current industry management practices for CCR fly 
ash that is used directly in concrete production as a substitute for 
Portland cement are not subject to the 40 CFR part 257 CCR 
requirements.
    Finally, EPA is proposing a new provision at Sec.  257.50(l) to 
exclude flue gas desulfurization (FGD) gypsum, when destined to be 
applied as an agricultural amendment at agronomically appropriate 
rates, and to exclude FGD gypsum destined for use as an ingredient in 
wallboard manufacturing.
    The proposed categorical exclusions for these three beneficial uses 
are based on the specific circumstances of these uses which incentivize 
the management of the CCR as a valuable commodity prior to beneficial 
use, and on EPA's proposed determination that these uses categorically 
meet the definition of beneficial use.
1. Definition of Beneficial Use
a. The First Three Beneficial Use Criteria Provide a Sufficient 
Framework for Beneficial Use Determinations
    EPA is proposing that the first three criteria of the beneficial 
use definition found at Sec.  257.53 provide a sufficient regulatory 
framework for identifying when any placement of CCR on the land, 
whether encapsulated or non-encapsulated, roadway or non-roadway, 
constitutes a beneficial use and not disposal under the RCRA statute.
    The first three beneficial use criteria currently apply to all CCR 
uses, whether encapsulated, unencapsulated, roadway, or non-roadway. 
When EPA proposed to revise the fourth beneficial use criterion in the 
2019 CCR proposal, the Agency noted in the proposal that the first 
three criteria still remain as finalized in the 2015 CCR rule. (84 FR 
40356)
    As noted in the 2015 CCR Rule, the first criterion, that CCR must 
provide a functional benefit, is designed to ensure that the material 
performs a genuine function in the product or use. In other words, the 
user must be able to demonstrate a legitimate reason for using CCR in 
the product other than the fact that it is an alternative to disposal 
of the material. For example, CCR provides a functional benefit when 
used as a replacement for cement in concrete because the CCR increases 
the durability of the concrete and is also more effective against 
degradation from salt water. 80 FR 21349.
    The second beneficial use criterion, which states that 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, is intended to demonstrate the use is truly 
``beneficial'' from an environmental perspective. 80 FR 21349. CCR can 
be substituted for many virgin materials that would otherwise have to 
be mined and processed for use. These virgin materials include 
limestone to make cement, and Portland cement to make concrete; mined 
gypsum to make wallboard, and aggregate, such as stone and gravel for 
uses in concrete and roadbed. It is beneficial to use secondary 
materials that would otherwise be disposed of, rather than to mine and 
process virgin materials, simultaneously reducing waste and 
environmental footprints. 80 FR 21329.
    The third criterion, that the use of 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, was intended to 
address both the legitimacy of the use and the potential environmental 
and human health consequences associated with the use of excess 
quantities of CCR, particularly unencapsulated CCR. 80 FR 21349-21350. 
The 2015 CCR final rule notes that this criterion can include a 
demonstration that relevant engineering specifications are met, such as 
the ASTM C 593 test for compaction, the ASTM D 560 freezing and thawing 
test, a seven-day compressive strength above 2760 kPa (400 psi), and 
ASTM Standard E2277-03,\43\ which provides standard guidance and a 
methodology for using CCR in a structural fill. 80 FR 21350.
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    \43\ The current version of the standard is ASTM Standard E2277-
14, titled ``Standard Guide for Design and Construction of Coal Ash 
Structural Fills,'' reapproved in 2019.
---------------------------------------------------------------------------

    Design standards are particularly important in the case of 
placement of large quantities of unencapsulated CCR in a single 
concentrated location, which the 2015 CCR Rule identified as the use 
most likely to resemble disposal, and that the current fourth criterion 
in the beneficial use definition was designed to address.\44\ ASTM 
Standard E2277, which outlines procedures for the design and 
construction of engineered structural fills using CCR, is particularly 
relevant for these cases. In defining beneficial use, the latest 
version of this standard states that one beneficial use defining factor 
is that CCR is used in a manner that protects human health and the 
environment, which directly speaks to the issue of disposal. The 
standard then goes on to discuss several environmental considerations; 
CCR engineering properties and behavior; CCR physical and engineering 
characteristics; design factors, such as site characterization and 
preparation, structural performance and compaction; and construction 
considerations, such as dust and erosion control and CCR placement.
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    \44\ 80 FR 21351.
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    All these provisions help ensure that unencapsulated CCR used as 
fill does not meet the statutory definition of disposal, i.e., the 
standards prevent the CCR and any constituent thereof from entering the 
environment or being emitted to the air or discharged into any waters, 
including groundwater. RCRA section 1004(3). The standard also guides 
users to determine all applicable local or state guidance, policies or 
regulations. Moreover, in addressing the need for chemical 
characterization, it guides users to recognize that states may require 
specific testing, such as to determine total composition or 
leachability of specific metals or other

[[Page 19011]]

elements in CCR. This standard, therefore, defines technical 
procedures, includes an environmental scope, and emphasizes users' 
responsibility to also ensure compliance with jurisdictional 
requirements. In this way, product design and engineering standards 
ensure that the use is beneficial and not disposal and play a role in 
reducing the potential for environmental and human health consequences 
in general. EPA is asking for comment on whether to incorporate the 
ASTM E2277 standard by reference in the regulations.
    Other types of non-roadway unencapsulated CCR uses include flowable 
fill; soil modification and stabilization; waste stabilization and 
solidification; aggregate; snow and ice control; and blasting grit. As 
noted in the 2015 CCR Rule, these additional unencapsulated uses, in 
contrast to structural fill, are not generally expected to be used in 
amounts requiring an environmental demonstration under the current 
fourth criterion in the beneficial use definition. Moreover, the use of 
CCR in these applications is generally not similar to the mounding that 
occurs in landfill situations, and several of these applications are 
structurally very different from landfills. 80 FR 21353. Like in the 
case of CCR structural fill, a number of standards are applicable to 
these uses.\45\ EPA requests comment on whether additional standards or 
guidance for applying the third criterion to these non-fill 
unencapsulated uses would be useful.
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    \45\ See Laboratory Testing and Other Relevant Standards and 
Guides for CCR Uses, available in the docket.
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b. Proposal To Eliminate the Fourth Beneficial Use Criterion
    The fourth criterion in the definition of beneficial use at Sec.  
257.53 was intended to specially address the question of whether the 
placement of unencapsulated CCR on the land in non-roadway applications 
is appropriately considered to be ``beneficial use'' or ``disposal'', 
even when the first three criteria are met, and if so, whether that 
``disposal'' warrants regulation. By focusing on non-roadway 
unencapsulated uses, the fourth criterion applies to uses that EPA 
identified in the 2015 CCR Rule as most likely to resemble disposal, 
i.e., the placement of large quantities of CCR in a single concentrated 
location. However, in preamble to the 2015 CCR Rule, EPA also agreed 
with commenters that, ``if constructed correctly, large scale fill 
operations can meet all of the criteria for a beneficial use.'' 80 FR 
21351.
    This criterion can be used to identify when those types of fill 
operations that most resemble disposal are genuine beneficial use by 
imposing a regulatory requirement that the CCR user conduct an 
environmental demonstration that the CCR use does not result in 
environmental releases that are (1) Higher than those from analogous 
products made without CCR, or (2) Pose risk to human health and the 
environment, when that use involves unencapsulated CCR non-roadway uses 
on the land over 12,400 tons. This demonstration requirement applies 
regardless of whether the CCR use involves a well-constructed fill 
operation, meeting all relevant product specifications, regulatory 
standards, or design standards, including the ASTM standard E2277 for 
structural fill.
    While EPA did not intend for the 12,400 ton threshold to be a 
bright line between beneficial use and disposal, based on comments from 
industry this appears to be how it has frequently operated.\46\ 
Complicating the situation is the fact that the 12,400 ton threshold 
was found to be based on data that were calculated with the wrong unit 
conversion factor (assuming the original data were reported in cubic 
feet rather than cubic yards). Much of the effort to ``fix'' the fourth 
criterion focused on identifying a more defensible basis for a 
threshold that would trigger an environmental demonstration, eventually 
resulting in the 2019 CCR proposal to set the threshold through 
location-based criteria. However, as discussed in Unit III.E. of this 
preamble, commenters raised substantive issues with this proposed 
approach, as well as with the alternative approaches that the Agency 
requested comment on. In addition, EPA's request for more information 
via the 2020 NODA did not indicate a clear path forward to establish an 
updated threshold.
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    \46\ For example, the cement industry has commented on the 
current beneficial use definition saying that ``[t]his narrowly 
tailored definition and the 12,400-ton threshold exemption from 
treatment as disposal were key elements of the rule for cement 
manufacturers, as it allowed plants to inventory minimum quantities 
of CCPs for use as raw materials in clinker manufacturing, cement, 
and blended cements.'' Comment submitted by the Portland Cement 
Association on the 2020 NODA, February 22, 2021. EPA-HQ-OLEM-2020-
0463-0035 (emphasis added).
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    After reviewing the comments on the 2019 CCR proposal and 2020 CCR 
NODA, EPA has reached the conclusion that the operational flaw in the 
fourth criterion is not the specific threshold that sets the conditions 
for requiring an environmental demonstration, but rather the 
environmental demonstration requirement itself. EPA finds that the 
environmental demonstration requirement in the fourth criterion, as 
currently written, poses an unacceptable barrier to beneficial use.
    EPA proposes to conclude, as several commenters on the 2019 CCR 
proposal and 2020 CCR NODA posited, that the first three criteria are 
sufficient in defining beneficial use and not disposal.\47\ In 
considering these comments, EPA has analyzed damage incidents involving 
use of unencapsulated CCR as structural fill, and has not found 
evidence that CCR use as structural fill that meets the first three 
beneficial use criteria presents a reasonable probability of adverse 
effects on health or the environment.\48\ Most of the incidents involve 
deposits of CCR in sand and gravel pits and quarries, which were 
explicitly defined as CCR landfills under the 2015 CCR rule, or sites 
that involve both CCR disposal and use as fill. The remaining seven 
cases do not clearly indicate compliance with the first three 
beneficial use criteria. When considering these incidents in the 
context of the past two decades of CCR beneficial use as engineered 
fill, involving millions of tons of CCR,\49\ as well as the most recent 
ASTM standards for CCR in structural fill discussed earlier, EPA finds 
that these criteria adequately address the conditions that constitute 
disposal, and therefore EPA is proposing to delete the fourth 
criterion.
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    \47\ See, e.g., comments from the Cross-Cutting Issues Group 
(CCIG) (EPA-HQ-OLEM-2018-0524-0165), National Mining Association 
(NMA) (EPA-HQ-OLEM-2018-0524-0161), American Coal Council (EPA-HQ-
OLEM-2020-0463-0029); Utility Solid Waste Activities Group (USWAG) 
(EPA-HQ-OLEM-2020-0463-0032) and EPA-HQ-OLEM-2018-0524-0064; 
Oglethorpe Power Corporation (EPA-HQ-OLEM-2018-0524-0176); Berkshire 
Hathaway Energy Co. (EPA-HQ-OLEM-2018-0524-0146), Aurora Energy, LLC 
(EPA-HQ-OLEM-2018-0524-0175): and American Coal Ash Association 
(ACAA) EPA-HQ-OLEM-2020-0463-0027.
    \48\ EPA 2025 Summary of Damage Incidents Associated with CCR 
Used as Structural Fill, available in the docket.
    \49\ Based on data reported annually by the American Coal Ash 
Association, over the past 24 years, the total amount of CCR that 
has been used as structural fill and embankments is more than 
85,000,000 tons (ACAA CCP Survey Results, 2000 to 2023).
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c. Applicability of the Revised Beneficial Use Definition
    EPA notes that the revised definition of beneficial use would not 
apply retroactively. The revised definition, when also considered in 
conjunction with EPA proposal to eliminate the definition of CCR pile 
(as discussed below), would apply to all future CCR beneficial use 
projects that occur after the effective date, whether conducted onsite 
at the generating utility or offsite.

[[Page 19012]]

This ensures consistency and clarity across all settings.
d. Interaction With State Beneficial Use Programs
i. Importance of the Role State Programs Play in Regulating Beneficial 
Use Under State Law
    States have historically implemented programs related to beneficial 
use of industrial, non-hazardous secondary materials under their state 
laws, and EPA has been recommending entities consult with state 
environmental agencies to ascertain that the state considers their 
proposed application a beneficial use. As discussed earlier, EPA 
excluded beneficial use of CCR from federal regulation under its May 
2000 regulatory determination, acknowledging that states bear the 
primary responsibility for CCR beneficial use programs under their 
existing state authorities. Surveys of state beneficial use programs 
conducted by the ASTSWMO have found that states use a variety of formal 
and informal decision-making processes or programs to make beneficial 
use determinations, and many state programs specifically address the 
use of CCR in such applications as cement manufacturing, concrete, 
construction projects, landfill cover, and structural 
fill.50 51 52 State decision-making authorities come from 
statutes, regulations, policy memoranda and guidelines, and some states 
also use agency discretion to review requests and decide whether uses 
are approvable. Different segments of states' environmental agencies 
can make these decisions, either alone, or in collaboration with other 
state agencies, such as health, agriculture or transportation. 
Decisions can come in the form of permits, written authorizations, 
beneficial use determinations, or other methods stipulated in the state 
regulations or statutes.
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    \50\ ASTSWMO (2007). 2006 Beneficial Use Survey Report. 
Association of State and Territorial Solid Waste Management 
Officials, November 2007.
    \51\ ASTSWMO (2012). Beneficial Use of Coal Combustion Residuals 
Survey Report. Association of State and Territorial Solid Waste 
Management Officials, September 2012.
    \52\ ASTSWMO (2021), Beneficial Use of Fill-Like Materials 
Survey Report, Association of State and Territorial Solid Waste 
Management Officials, February 2021.
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    The various approaches that states have adopted under state law to 
determine when a use of a material is beneficial or is disposal under 
state laws have allowed states to consider important regional issues 
and interests, and the specific geographic, geologic, hydrologic and 
climatic conditions at proposed sites. The importance of state 
flexibility in making these determinations is reflected in the official 
position of the ASTSWMO Board of Directors, which states ``ASTSWMO 
prefers beneficial use guidance to a regulatory approach. States need 
flexibility to implement procedures that work within their existing 
regulatory framework and for making site-specific technical decisions. 
ASTSWMO agrees that a proposed use of large quantities of CCR without a 
proven functional benefit should be thoroughly investigated, due to 
risks of environmental harm, and should not be necessarily viewed as a 
beneficial use. However, a ``one-size-fits-all'' regulatory approach is 
not practical or effective.'' \53\
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    \53\ ASTSWMO. (2023). 2023 ASTSWMO statement on coal combustion 
residuals program implementation. Retrieved from https://astswmo.org/2023-astswmo-statement-on-coal-combustion-residuals-program-implementation/.
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    As noted in the 2015 CCR Rule, under the current regulations, EPA 
expects potential non-roadway users of unencapsulated CCR below the 
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 With the proposed 
elimination of the 12,400-ton threshold, EPA would likewise expect all 
CCR users of unencapsulated CCR to continue to work with their state to 
ensure that the use is considered beneficial under the state 
requirements. EPA requests comment on whether the definition of 
beneficial use should include a requirement in the regulations to 
document state approval of the beneficial use under the state law.
ii. EPA Technical Assistance on Beneficial Use Determinations
    Over the years, EPA has issued a number of documents to provide 
states technical assistance on making beneficial use determinations, 
including the type of site-specific technical decisions that may apply 
to certain CCR beneficial uses, including a Beneficial Use Methodology, 
Beneficial Use Compendium, national-level beneficial use evaluations, 
updates to Industrial Waste Management Evaluation Model, and the 
development of Leaching Environmental Assessment Framework (LEAF) Test 
Method.\54\ EPA requests comment on whether and what sort of additional 
guidance documents would be helpful to states making CCR beneficial use 
decisions under their state authority.
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    \54\ These tools and other technical assistance documents that 
address barriers to the beneficial use of non-hazardous secondary 
materials, including CCR, which can be found at https://www.epa.gov/smm/sustainable-management-industrial-non-hazardous-secondary-materials#04 and on the Agency's CCR Reuse web page at https://www.epa.gov/coal-combustion-residuals/coal-combustion-residuals-reuse.
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2. Revisions Related to CCR Accumulations
a. Overview of Proposed Changes Related to CCR Accumulations
    EPA is proposing new definitions of ``CCR storage pile'' and 
``temporary accumulation'' to establish a single set of requirements 
applicable to all temporary placement of unencapsulated CCR on the 
land, whether managed onsite or off-site, and whether destined for 
beneficial use or disposal. Rather than characterizing such placements 
as either disposal or beneficial use, EPA considers that these 
activities are better characterized as ``storage,'' with criteria 
established pursuant to the authority in RCRA section 1008(a)(3) to 
control releases. These proposed standards are similar to the 
definitions that EPA proposed in the 2019 CCR rule, with some 
adjustments to make the requirements clearer and less burdensome.
    As discussed in the 2019 CCR proposal, under the current 
regulations, CCR piles are defined as any ``non-containerized 
accumulation of solid, non-flowing CCR that is placed on the land. CCR 
that is beneficially used off-site is not a CCR pile.'' See Sec.  
257.53. The first part of this definition mirrors the RCRA definition 
of disposal, which is defined in part as the ``placing of any solid 
waste or hazardous waste into or on any land or water so that such 
solid waste or hazardous waste or any constituent thereof may enter the 
environment or be emitted into the air or discharged into any waters, 
including ground waters.'' See 42 U.S.C. 6903(3). Thus, CCR piles are 
considered disposal units and therefore are currently included in the 
definition of CCR landfill. See Sec.  257.53.
    CCR accumulations that are containerized (i.e., that are subject to 
measures that the facility has taken to control releases), are not 
considered ``CCR piles'' under the current regulations, even if they 
otherwise meet the conventional description of a ``pile'' (i.e., an 
accumulation or mound of CCR). Examples of containerization measures 
include placement of CCR on an impervious base such as asphalt, 
concrete or geomembrane; leachate and run off collection; and walls or 
wind barriers.

[[Page 19013]]

    In addition, off-site non-containerized accumulations of CCR that 
meet the definition of beneficial use are also not considered ``CCR 
piles'', while onsite non-containerized accumulations of CCR (at an 
electric utility or independent power producer site) are CCR piles, 
even if they would otherwise meet the definition of beneficial use. See 
Sec.  257.53 (definition of CCR pile); 80 FR 21356 (April 17, 2015). 
This regulation of onsite CCR accumulations as CCR piles applies to all 
onsite non-containerized CCR accumulations, including CCR that has been 
used as structural fill onsite. As stated in the Legacy Final Rule, 
``under the existing regulations, the direct placement of CCR on the 
land on site of a utility, with nothing to control releases is, by 
definition, a CCR pile and therefore not beneficial use. The examples 
of historical [CCRMU] discussed in the proposal, structural fill and 
CCR placed below currently regulated CCR units onsite of a utility also 
clearly fit that definition.'' 89 FR 39050.
    Thus, in summary, under current regulations, the following CCR 
accumulations on the land are CCR piles and therefore regulated as CCR 
landfills: any non-containerized CCR accumulation onsite at an electric 
utility and any non-containerized CCR accumulation off-site that does 
not meet the definition of beneficial use.
    This regulatory approach has been the source of confusion, and 
stakeholders have also raised concerns over the inconsistency of this 
approach. In the 2019 CCR proposal, EPA proposed a definition of ``CCR 
storage pile'' in order to establish a single set of requirements 
applicable to all temporary placement of unencapsulated CCR on the 
land, whether managed onsite or off-site, and whether destined for 
beneficial use or disposal, to ensure that such accumulations are 
designed and managed to control releases of CCR to the environment. 
Rather than characterizing such activities as either disposal or 
beneficial use, EPA proposed that these activities are better 
characterized as ``storage,'' with criteria established pursuant to the 
authority in section 1008(a)(3) to control releases. In addition, as 
discussed earlier, EPA is proposing to apply the definition of 
``beneficial use'' equally to onsite and off-site beneficial uses.
    After considering the public comments on the 2019 CCR proposal, EPA 
is proposing several revisions to Sec.  257.53 and conforming changes 
in Sec.  257.2 to address the management of temporary CCR 
accumulations. Specifically, EPA is proposing to define a CCR storage 
pile as ``any temporary accumulation of solid, non-flowing CCR placed 
on the land that is designed and managed to control unpermitted 
releases of CCR to the environment.'' In addition, EPA is proposing to 
define ``temporary accumulation'' to mean ``an accumulation on the land 
that is neither permanent nor indefinite. To demonstrate that the 
accumulation on the land is temporary, the CCR must be removed from the 
pile at the site. The entity engaged in the activity may use ordinary 
business records to document that the CCR in the pile will be removed 
according to a specific timeline.''
    The requirement to control unpermitted releases in the definition 
of CCR storage pile is intended to be consistent with the definition of 
disposal in 42 U.S.C. 6903(3). As stated in that definition, disposal 
includes the ``placing of any solid waste or hazardous waste into or on 
any land or water so that such solid waste or hazardous waste or any 
constituent thereof may enter the environment or be emitted into the 
air or discharged into any waters, including groundwaters.'' When 
significant and persistent volumes of unencapsulated CCR are present, 
similarities exist in the potential risks posed to human health, 
groundwater resources, or the air between the placement of CCR in piles 
and placement in CCR landfills, if inappropriately managed. See 80 FR 
21356.
    Examples of measures that might be used to control releases from a 
CCR storage pile include: periodic wetting, application of surfactants, 
tarps or wind barriers to suppress dust; tarps or berms for preventing 
contact with precipitation and controlling run-on/runoff; and 
impervious storage pads, geomembrane liners or tarps for soil and 
groundwater protection. EPA is not proposing to impose a specific set 
of control measures, as the amount of CCR stored, the location of 
storage, and the prevailing weather conditions may affect which 
controls are appropriate. Therefore, EPA intends to provide the 
entities engaged in the activity with flexibility to determine the 
control measures most appropriate to meet the requirement to control 
releases at a given site. This flexibility also ensures that EPA's 
requirements do not contradict any state or local requirements for the 
use of prescribed controls.
    In addition, limiting the definition of CCR storage pile to 
temporary accumulations prevents the CCR being stored in lieu of 
disposal, and also effectively limits the amount of unencapsulated CCR 
that will be placed and persist in one location. Due to these factors, 
EPA considers that it is not necessary to impose on CCR storage piles 
the same set of technical requirements as for CCR landfills, and that 
meeting the requirement to control releases of CCR in the definition of 
a CCR storage pile, combined with meeting the definition of temporary 
accumulation, adequately addresses the conditions that would otherwise 
constitute disposal of CCR, either onsite or off-site.
    EPA is also proposing a conforming change to the definition of a 
CCR landfill to remove ``CCR pile'' from the list of units considered 
to be a landfill and instead include ``accumulations of CCR on the land 
that do not meet the definition of a CCR storage pile'' in the 
definition of CCR landfill. This proposed change would apply to the 
definition of CCR landfill in Sec. Sec.  257.2 and 257.53. In addition, 
EPA is proposing a technical correction to the definition of CCR 
landfill in Sec.  257.2 so that definition conforms to the definition 
of CCR landfill in Sec.  257.53, including changes related to the 
January 16, 2025 CCR direct final rule and companion proposed rule. See 
90 FR 4639.
b. Proposed Changes as Compared to the 2019 CCR Proposal and Requests 
for Comment
    While the changes proposed in this rule are similar to those 
proposed in the 2019 CCR rule, EPA has made some adjustments to make 
the requirements more clear and less burdensome. These adjustments 
include: (1) Removing the definition of ``CCR pile'' and the 
designation of ``CCR pile'' from the definition of landfill, (2) Not 
including designation of ``enclosed structure'' in the regulation of 
CCR, (3) Not listing the specific examples of control measures for CCR 
storage piles in the regulations, and (4) Clarifying in the definition 
of ``temporary accumulation'' that ordinary business records are 
sufficient for documenting that the CCR has been completely removed 
from the pile.
    EPA is proposing to remove the definition of ``CCR pile'' and the 
designation of ``CCR pile'' from the definition of landfill because of 
the possible confusion between ``CCR pile'' and ``CCR storage pile'', 
and the redundancy of the ``CCR pile'' definition with the proposed 
revision to the definition of CCR landfill, which proposes to add ``any 
accumulation of CCR on the land that does not meet the definition of a 
CCR storage pile''. This added language to the landfill definition 
covers any unit that would be considered a ``CCR pile'' under the 
current regulations, and therefore it is

[[Page 19014]]

no longer necessary to have a separate term for this type of 
accumulation.
    EPA is also making adjustments to the definitions of ``CCR storage 
pile'' and ``temporary accumulation'' that were originally proposed in 
2019 to increase the flexibility of these requirements and remove 
unnecessary burdens. The definition of CCR storage pile is proposed to 
require the unit is designed to control unpermitted releases of CCR in 
order to account for the fact that such units are often subject to 
permitting requirements that directly affect the management of CCR. In 
addition, EPA is proposing to not include the specific examples of 
controlling releases from CCR piles that were proposed to be included 
in the definition in 2019, namely periodic wetting, application of 
surfactants, tarps or wind barriers to suppress dust; tarps or berms 
for preventing contact with precipitation and controlling run-on/
runoff; and impervious storage pads or geomembrane liners for soil and 
groundwater protection. While all these practices remain valid examples 
of controlling unpermitted releases, including them in the regulatory 
language gave some commenters the false impression that EPA intended 
these specific controls were always required, when in some 
circumstances they may not be. As noted earlier, EPA intends to provide 
the entities engaged in the activity with flexibility to determine the 
control measures most appropriate to meet the requirement to control 
releases at a given site.
    Similarly, EPA is not proposing the definition of ``enclosed 
structure'' and its designation as a management unit that would not be 
a CCR storage pile because this definition caused some commenters to 
conclude that management in an enclosed structure would be a 
requirement of the rule. While enclosed structures would continue to be 
one method to ensure that unpermitted releases are controlled, such a 
structure is not required and including it in the regulation is 
unnecessary and potentially confusing.
    Finally, EPA is proposing to remove language from the 2019 CCR 
Proposal definition of ``temporary accumulation'' that stated the 
``entity engaged in the activity must have a record in place, such as a 
contract, purchase order, facility operation and maintenance, or 
fugitive dust control plan'' and instead has clarified that the entity 
``may use ordinary business records to demonstrate that the CCR in the 
pile will be removed according to a specific timeline.'' The specific 
types of business records would depend on the beneficial use and the 
pile location, but some examples may include sales and transportation 
contracts, invoices and sales receipts, inventory logs, or shipment 
records demonstrating that the CCR storage pile will be removed within 
a specific timeline.
    EPA requests comments on the adjustments to the 2019 CCR Proposal 
language, as well as on the option to keep the current structure of 
regulating non-containerized CCR piles that do not meet the definition 
of beneficial use as disposal units and simply removing the distinction 
between onsite and off-site piles.
    EPA is also requesting comment on the types of business records 
that would best demonstrate that a CCR storage pile is ``temporary'' 
and whether a pile custodian could demonstrate that the pile will be 
removed according to a specific timeline by issuing a certification. 
For example, in cases where pile custodians are not able to provide 
business records to demonstrate that piles are temporary due to 
existence of proprietary business information, a custodian's 
certification may be an appropriate alternative way to show that the 
CCR in the pile will be removed according to a specific timeline.
    EPA is also requesting comment on adding a provision within the 
proposed definition of a temporary accumulation to allow CCR to be 
removed from CCR storage piles on a rolling basis. This provision would 
expand the proposed definition to cover cases in which storage piles 
are supporting established, ongoing operations, and not just the piles 
for which removal of a final amount of CCR is expected within a 
specific timeframe. The purpose of the provision would be to enable 
facilities to continue their operation while also ensuring that the CCR 
is continuously getting beneficially used or transferred for disposal, 
in lieu of being stored indefinitely in lieu of disposal. The provision 
would be similar to how the speculative accumulation requirements that 
apply to hazardous secondary materials that are destined for recycling 
work. See Sec.  261.1(c)(8). Specifically, entities would demonstrate 
that their CCR is not being stored in lieu of disposal by removing at 
least 75% of the material from the storage pile each calendar year. The 
proximity of the pile to established, ongoing operation could help 
demonstrate that the provision is appropriate for the operation. In 
addition, EPA is requesting comment on whether to establish a provision 
that would authorize a one-time pile that would not be subject to 
speculative accumulation limits, provided that all CCR was removed 
within a specific time, e.g., 9 months. For example, such a provision 
could potentially apply to one-time, short-term piles primarily set up 
to meet construction demands where a timeframe of 9 months, which 
covers the entirety of the construction season, is sufficiently long 
for CCR to be removed.
3. Exclusions for Specific Beneficial Uses
a. Exclusion for CCR Used in Cement Manufacturing at Cement Kilns
    EPA is proposing to add a provision at Sec.  257.50(k) to exclude 
CCR at cement kilns that is destined for use as an ingredient in cement 
manufacturing from the requirements of 40 CFR part 257. This proposed 
categorical determination recognizes the benefit CCR provides as an 
ingredient in cement manufacturing, and how this benefit incentivizes 
its management as a valuable commodity at the cement kiln and helps 
ensure it will be appropriately incorporated in an encapsulated 
beneficial use. This proposed change would remove regulatory 
uncertainty for both the cement kilns and the regulatory authorities, 
simplify implementation, and reduce burden. EPA is also requesting 
comment on whether it would be helpful to include a regulatory 
clarification explaining that the current industry management practices 
for CCR fly ash that is used directly in concrete production as a 
substitute for Portland cement are not subject to the 40 CFR part 257 
CCR requirements.
    An encapsulated beneficial use is one that binds the CCR into a 
solid matrix that minimizes mobilization into the surrounding 
environment, such as the addition of CCR in cement manufacturing at 
cement kilns and incorporation in concrete. In general, encapsulated 
uses of CCR must comply with the first three criteria in the definition 
of beneficial use found at Sec.  257.53: (1) The CCR used 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, and (3) The use of 
CCR must meet relevant product specifications, regulatory standards, or 
design standards when available, and when such standards are not 
available, CCR are not used in excess quantities.
    EPA has determined that CCR used as an ingredient in cement 
manufacturing satisfies these three criteria. CCR used in cement 
manufacturing provides a functional benefit in that it increases the 
durability of concrete and is more effective in combating degradation 
from

[[Page 19015]]

salt water. CCR is also directly used as a substitute for virgin 
materials, such as silica, iron, clay, shale, and bauxite in kiln feed, 
gypsum in finished portland cement, and clinker in blended cement 
products, reducing the need for mining, processing, and transport of 
virgin materials and the further disturbance of the environment. 
Lastly, when CCR is used as a commercial product, the amount of CCR 
used is controlled by meeting careful product specifications.
    Several decades of record support that the current beneficial use 
of CCR as a replacement for industrial raw materials (e.g., Portland 
cement, virgin stone aggregate, lime, gypsum) provides substantial 
annual life cycle environmental benefits for these industrial 
applications. Cement is a critical ingredient in the production of 
concrete, and cement and concrete manufacturing has proven to be among 
the highest value encapsulated use of CCR, providing economic and 
environmental benefits. Cement kilns have shown to treat CCR as a high-
value feedstock, the same as other raw materials, as it is carefully 
inventoried and stored at onsite facilities as valuable commodities in 
accordance with the applicable standards, practices, and conditions in 
a manner analogous to natural raw materials or other industrial 
byproducts used as raw materials.\55\ In 2020, EPA estimated that the 
environmental and human benefit of using one ton of CCR in lieu of 
virgin materials in the production of portland cement is $69.90 
compared to using one ton of virgin fill materials at $2.28. This puts 
cement manufacturing among the highest value encapsulated uses of CCR, 
providing economic and environmental benefits far greater than those 
provided by other uses, and offering further economic incentive for it 
to be treated as a valuable commodity. Cement manufacturing also uses a 
tightly controlled and precise chemical combination in its complex 
systems process where extensive and carefully calibrated environmental 
controls are used. Cement kilns will require or conduct laboratory 
testing to ensure that supplied CCR meet the applicable specifications 
for use in cement or it is rejected.\56\ Cement kilns will also retain 
safety data sheets (SDSs) for CCR materials procured for use in the 
cement manufacturing process, including fly ash, bottom ash, and 
synthetic gypsum, to ensure the health and safety of its employees and 
visitors.\57\
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    \55\ EPA-HQ-OLEM-2020-0463, 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. PCA Response to EPA Request for 
Supplemental Documentation. February 2021.
    \56\ Id.
    \57\ Id.
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    In 2014, EPA evaluated the risks and benefits of using CCR in 
cement and concrete and based on the findings of the evaluation, 
concluded that environmental releases of constituents of potential 
concern during use by the consumer are comparable to or lower than 
those from analogous non-CCR products or are at or below relevant 
regulatory and health-based benchmarks for human and ecological 
receptors.\58\ Furthermore, the cement industry already complies with 
stringent air and water permitting requirements to control releases 
from CCR stored in piles at cement kilns before its use in cement 
manufacturing. Cement kilns must comply with dust suppression measures 
under their Title V Permits by which they are subject to visible 
emissions limits for all CCR storage piles and requirements to control 
and minimize fugitive dust. They also must comply with stormwater 
control requirements under National Pollutant Discharge Elimination 
System (NPDES) Permits to mitigate environmental impacts of CCR storage 
and all other material stored in piles.\59\ EPA requests comment on the 
exclusion of CCR beneficially used at cement kilns from regulation.
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    \58\ EPA 2014. Coal Combustion Residual Beneficial Use 
Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard. https://www.epa.gov/sites/default/files/2014-12/documents/ccr_bu_eval.pdf. 
February 2014.
    \59\ EPA-HQ-OLEM-2020-0463, 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. PCA Response to EPA Request for 
Supplemental Documentation. February 2021.
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Fly Ash Used in Concrete
    EPA is also requesting comment on whether it would be helpful to 
include a regulatory clarification explaining that CCR fly ash that is 
used directly in concrete production as a substitute for Portland 
cement is not subject to the CCR requirements of 40 CFR part 257.
    As a practical matter, it is EPA's understanding that the current 
handling of fly ash is already not subject to part 257 CCR requirements 
because fly ash that is substituting for Portland cement is not placed 
on the land before being incorporated into concrete. As explained in 
the 2019 CCR proposal, fly ash marketed for beneficial use in concrete 
production is consistent across the industry; fly ash is collected in a 
dry powder form, stored in silos, domes, or buildings and transferred 
pneumatically via truck or rail transportation in a self-contained 
system from start to end. The reason for the containment is that fly 
ash provides mechanical and chemical benefits when used in concrete, 
making it a valuable ingredient and fully warranting the protection of 
its properties through handling and storage. 84 FR 40363-44. In 
addition, the incorporation of fly ash in concrete is a well-
established beneficial use, and EPA has concluded that environmental 
releases of constituents of potential concern during use by the 
consumer are comparable to or lower than those from analogous non-CCR 
products or are at or below relevant regulatory and health-based 
benchmarks for human and ecological receptors.\60\ Thus, current 
practices for managing the fly ash for use in concrete production are 
already functionally not subject to part 257 CCR requirements and a 
categorical exclusion in the regulations is not strictly necessary.
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    \60\ EPA 2014. Coal Combustion Residual Beneficial Use 
Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard. https://www.epa.gov/sites/default/files/2014-12/documents/ccr_bu_eval.pdf.February 2014.
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    However, given that EPA is proposing categorical exclusions for 
other high-value beneficial uses, the Agency does not want to introduce 
any confusion regarding the regulatory status of CCR fly ash used in 
concrete production, and requests comment on whether a regulatory 
clarification to that effect would be helpful.
b. Exclusion for FGD Gypsum Beneficially Used in Agriculture
    EPA is also proposing to add a provision at Sec.  257.50(l) to 
exclude flue gas desulfurization (FGD) gypsum from the requirements of 
40 CFR part 257 when destined to be applied as an agricultural 
amendment at agronomically appropriate rates. FGD gypsum is a type of 
CCR generated from the pollution control technologies designed to 
reduce sulfur gas emissions from electric utilities and is the largest 
source of synthetic gypsum in the United States. As with the exclusion 
for CCR beneficially used in cement kilns, this proposed change would 
also remove regulatory uncertainty for both the agricultural industry 
and the regulatory authorities, simplify implementation, and reduce 
burden for beneficially used FGD gypsum applied as an agricultural 
amendment at agronomically appropriate rates.
    Under current regulations, FGD gypsum, when used for agricultural 
purposes, must comply with all four criteria in the beneficial use 
definition found at 40 CFR 257.53: (1) The CCR

[[Page 19016]]

used 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 CCR must meet relevant product specifications, regulatory 
standards, or design standards when available, and when such standards 
are not available, CCR are not used in excess quantities, and (4) For 
uses over 12,400 tons, must provide an environmental demonstration that 
environmental releases to groundwater, surface water, soil and air are 
comparable to or lower than those from analogous products made without 
FGD gypsum, or that environmental releases will be at or below relevant 
regulatory and health-based benchmarks for human and ecological 
receptors during use.\61\
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    \61\ While EPA is proposing to remove the fourth criterion from 
the definition of beneficial use, the Agency is including in this 
discussion a reference to the fourth criterion both because it 
reflects the current regulations and because the specific beneficial 
use evaluation that was performed for the use of FGD gypsum in 
agriculture is relevant to this specific proposed exemption.
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    For the first criterion, FGD gypsum acts in several beneficial ways 
in agricultural soil applications, such as nutrient amendments for 
calcium and sulfur deficiencies, soluble phosphorus and aluminum 
toxicity adverse effects reduction, the amelioration of sodic soils, 
and the supportive aggregation of clay soil, which improves water 
infiltration. The primary crops that benefit from the application of 
gypsum include peanuts, cotton, corn, wheat, and alfalfa.\62\ For the 
second criterion, FGD gypsum can substitute for mined gypsum, which is 
a mineral that occurs naturally in sedimentary rock formations, because 
both materials are composed primarily of calcium sulfate. EPA has 
previously concluded that many of the constituents in FGD gypsum are 
comparable to those in mined gypsum.\63\ For the third criterion, under 
U.S. Department of Agriculture (USDA) standards, amendment provider has 
the responsibility to provide chemical analysis documentation of the 
FGD gypsum which must include the calcium and sulfur content and 
content of heavy metals, and all other potential contaminants, and 
concentrations of potential contaminants cannot exceed maximum 
allowable concentrations.\64\ The USDA stipulates that annual 
application rates should not exceed 5 tons/acre for the purposes 
defined in the Amending Soil Properties with Gypsum Products (Ac.) 
(333) Conservation Practice Standard.\65\ Thus, when applied as an 
agricultural amendment at agronomically appropriate rates, FGD gypsum 
meets the first three beneficial use criteria.
---------------------------------------------------------------------------

    \62\ EPA-HQ-OLEM-2020-0463, 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. Agricultural Retailers 
Association Comment. October 2019.
    \63\ U.S. EPA, US Department of Agriculture, RTI International. 
Beneficial Use Evaluation: Flue Gas Desulfurization Gypsum as an 
Agricultural Amendment. March 2023.
    \64\ USDA. Conservation Practice Standard Amending Soil 
Properties with Gypsum Products. June 2015.
    \65\ Id.
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    In addition, in 2023 EPA conducted a beneficial use evaluation of 
FGD gypsum to demonstrate how an analytical framework can be used to 
evaluate the potential for adverse environmental impacts from a wide 
range of industrial materials and their proposed beneficial uses, 
specifically the use of FGD gypsum as an agricultural amendment.\66\ 
Based on the results of this study, EPA concluded that all potential 
risks resulting from soil treated with FGD gypsum are likely to fall 
below level of concern under actual use scenarios, and determined the 
beneficial use of FGD gypsum can provide meaningful benefits to 
agricultural fields while remaining protective of human health and the 
environment.\67\
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    \66\ U.S. EPA, US Department of Agriculture, RTI International. 
Beneficial Use Evaluation: Flue Gas Desulfurization Gypsum as an 
Agricultural Amendment. March 2023.
    \67\ Id. While the study identifies some limited potential for 
risk from release of selenium to surface water when FGD gypsum is 
applied across every available field at the highest rates and 
frequencies, even in this extreme and unlikely scenario, identified 
risks can be mitigated through minor limits on application 
practices.
---------------------------------------------------------------------------

    EPA's proposed exemption from the requirements of 40 CFR part 257 
also applies to the storage of FGD gypsum while waiting at agricultural 
retail facilities before being applied in agricultural fields. As 
discussed above, FGD gypsum is a valuable resource to farmers, and 
agricultural retailers have an incentive to manage it in a way that 
avoids unpermitted releases to the environment, ensuring that this 
resource will be used. FGD gypsum is stored at agricultural retail 
facilities typically for only a three- to four-month period during 
growing season in piles at around 10,000 tons.\68\ Generally, FGD 
gypsum comes via truck from power plants in April, May, and June of 
each year. Once FGD gypsum arrives, it is placed on a compressed dirt 
area. It is then compressed in stacks using a front-end loader. When 
runoff occurs, it is scooped back in and mixed with the existing 
material. A holding pond is used to capture gradually declining 
material. As needed, the pile is re-shaped and re-graded to maintain 
integrity. The pile is typically emptied by the end of June. Weight 
measures are used for inventory tracking, to accurately record how much 
FGD gypsum comes in and how much is sent out. The Agricultural 
Retailers Association (ARA) emphasizes the importance of controlling 
``shrinkage'' of the FGD gypsum to minimize loss and indicates that 
these management practices are generalizable and applied 
everywhere.\69\
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    \68\ USDA. Conservation Practice Standard Amending Soil 
Properties with Gypsum Products. June 2015.
    \69\ EPA meeting with Agricultural Retailers Association, held 
on May 27, 2020. EPA-HQ-OLEM-2020-0463-0003.
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    The proposed exemption recognizes that the FGD gypsum as an 
agricultural amendment at agronomically appropriate rates is a well-
established beneficial use practice that provides environmental 
benefits and raises minimal health or environmental concerns. This 
proposed exemption also incentivizes the continuation of management 
practices at agricultural retail facilities that prevent loss of the 
material and ensure it will in fact be incorporated as an agricultural 
amendment.
c. Exclusion for FGD Gypsum Beneficially Used in Wallboard
    In addition, EPA is proposing an exclusion in Sec.  257.50(l) for 
FGD gypsum that is destined for use as an ingredient in wallboard 
manufacturing. This proposed regulatory revision provides regulatory 
certainty by codifying EPA's current position on FGD gypsum managed as 
a valuable commodity and used in wallboard, as expressed in the 
preamble to the 2015 CCR rule and subsequent guidance.70 71 
Several circumstances factor into this proposal. Firstly, the use of 
FGD gypsum as replacement for mined gypsum in wallboard, is significant 
at around 75% of all FGD gypsum being beneficially used.\72\ FGD gypsum 
serves exactly the same function in wallboard as mined gypsum and meets 
all commercial specifications. Its use decreases the need to mine 
natural gypsum, conserving the natural resource and energy that would 
otherwise be needed to mine natural gypsum. Thus, the use of FGD gypsum 
in place of mined

[[Page 19017]]

gypsum can offer significant environmental benefits.
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    \70\ 80 FR 21348.
    \71\ https://www.epa.gov/coal-combustion-residuals/frequent-questions-about-beneficial-use-coal-combustion-residuals#t2q5.
    \72\ ACAA 2023 CCR Survey Results, https://acaa-usa.org/wp-content/uploads/2025/05/2023-Production-and-Use-Survey-Results-FINAL.pdf.
---------------------------------------------------------------------------

    Secondly, EPA evaluated this use in 2014, and, based on FGD gypsum 
wallboard that meets relevant physical and performance standards, 
conforms to standard design specifications, and incorporates FGD gypsum 
from pollution control devices used in the United States, concluded 
that FGD gypsum wallboard is an appropriate beneficial use.\73\
---------------------------------------------------------------------------

    \73\ U.S. Environmental Protection Agency. 2014 Coal combustion 
residual beneficial use evaluation: Fly ash concrete and FGD gypsum 
wallboard. https://www.epa.gov/coal-combustion-residuals/coal-combustion-residual-beneficial-use-evaluation-fly-ash-concrete-and.
---------------------------------------------------------------------------

    Finally, synthetic gypsum is a product of the FGD process at coal-
fired power plants. The utility designs and operates its air pollution 
control devices to produce an optimal product, including the oxidation 
of the FGD to produce synthetic gypsum. After its production, the 
utility treats FGD gypsum as a valuable input into a production 
process, protecting the inventory so the material can in fact be 
incorporated into wallboard. Moreover, wallboard plants are frequently 
sited in close proximity to power plants for access to raw material, 
with a considerable investment involved. Thus, the proposed 
codification recognizes that the FGD gypsum use as an ingredient in the 
manufacture of wallboard is a well-established and widely accepted 
practice that provides environmental benefits while raising minimal 
health or environmental concerns. The proposed codification 
incentivizes the continuation of management practices for FGD gypsum 
that prevent loss of the material and ensure it will in fact be 
incorporated into wallboard.

D. Federal CCR Permitting Rule-Reopening the Comment Period

    On February 20, 2020, EPA proposed a rule (85 FR 9940) entitled 
Hazardous and Solid Waste Management System: Disposal of Coal 
Combustion Residuals From Electric Utilities; Federal CCR Permit 
Program (Federal CCR permit program proposed rule), that would 
establish a Federal CCR permit program that will operate in Indian 
country and in nonparticipating States. The proposal describes how EPA 
will implement a Federal CCR permit program in accordance with the 
requirements of the WIIN Act, and includes the requirements and 
procedures EPA intends to use to issue Federal permits for disposal and 
associated solid waste management of CCR in 40 CFR part 257, subpart E. 
The public comment period for the proposed Federal CCR permit rule ran 
from February 20, 2020, through August 7, 2020.
    Given that it has been over five years since the proposal was 
published, EPA intends to reopen the comment period on the Federal CCR 
permit program proposed rule in a subsequent notice to provide the 
public with another 30 days to comment on the proposal. To effectuate 
this, EPA will publish a separate document in the Federal Register 
announcing that the comment period has been reopened and that comments 
need to be submitted to Docket ID No. EPA-HQ-OLEM-2019-0361.\74\
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    \74\ To submit comments on the proposed Federal CCR permit 
program rule, search Docket ID No. EPA-HQ-OLEM-2019-0361, online at 
https://www.regulations.gov.
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V. The Projected Economic Impact of This Action

A. Introduction

    EPA estimated the costs and benefits of this action in a Regulatory 
Impact Analysis (RIA), which is available in the docket for this 
action.

B. Affected Universe

    The universe of units and facilities affected by this action 
includes four categories. The first is comprised of CCR landfills and 
surface impoundments at facilities actively producing power and placing 
CCR into onsite units on or after October 19, 2015. These units were 
first regulated under the 2015 CCR Final Rule. The RIA identifies 783 
units at 303 facilities. The second category consists of CCR surface 
impoundments at facilities that stopped producing power and placing CCR 
into onsite unites on or before October 19, 2015. These units were 
first regulated under the 2024 Legacy Final Rule. The RIA identifies 97 
surface impoundments at 49 facilities. The third category consists of 
CCRMU at regulated facilities. These units were first regulated under 
the 2024 Legacy Final Rule. The RIA identifies 195 CCRMU at 104 
facilities. The fourth category consists of businesses who purchase and 
store CCR and other byproducts of coal combustion onsite as inputs for 
industrial purposes (i.e., for beneficial use). Beneficial use of CCR 
was first defined under the 2015 CCR Final Rule. The RIA identifies a 
range of 816 to 1,256 businesses that use CCR as an industrial input.
    Note that since many of the provisions of this action grant 
flexibilities to permitting authorities or apply based on site-specific 
characteristics or practices, the total number of CCR units and 
facilities affected by each provision my differ from the totals listed 
in this section. The RIA estimates and details the number of facilities 
and units affected by each provision in Chapter 2.

C. Baseline Costs

    The baseline costs of this rule consist of all costs associated 
with actives required to comply with the existing suite of CCR 
regulations. These regulations include the 2015 CCR Final Rule, the 
2020 Part A Final Rule, and the 2024 Legacy Final Rule. The RIA also 
includes cost savings attributable to the 2025 CCRMU Deadline Extension 
Proposed Rule in the baseline. The difference between these baseline 
compliance costs and compliance costs under the provisions of this 
action are estimated and presented as cost savings in the RIA and 
summarized in the following section.

D. Costs and Benefits of the Proposed Rule

    This proposed rule modifies the existing regulatory framework of 
the CCR program with four broad categories of changes that result in 
cost savings. The first set of changes broadens eligibility criteria 
for closure-by-removal certifications and deferrals for Legacy CCR SIs 
previously closed under state or federal oversight. The annualized cost 
savings associated with these changes are estimated to be approximately 
$9-$10 million per year when discounting at 3% and to be approximately 
$15-$17 million per year when discounting at 7%.
    The second set of changes rescinds all CCRMU provisions from the 
2024 Legacy Final Rule. The annualized cost savings associated with 
this change is estimated to be approximately $86-$100 million per year 
when discounting at 3% and approximately $117-$139 million per year 
when discounting at 7%.
    The third set of changes allows state-authorized and federal 
permitting authorities to make certain site-specific determinations 
regarding groundwater monitoring points of compliance, groundwater 
protection standards, closure performance standards, closure timelines, 
and post-closure requirements. The annualize cost savings associated 
with these changes is estimated to be approximately $74-$78 million per 
year when discounting at 3% and approximately $96-$101 million per year 
when discounting at 7%.
    The fourth set of changes amend the beneficial use regulations by 
removing demonstration requirements, changing definitions regarding 
accumulations of

[[Page 19018]]

CCR, and exempting certain uses from regulatory requirements. The 
annualized cost savings associated with these changes is estimated to 
be approximately $6 million per year when discounting at 3% and 
approximately $6 million per year when discounting at 7%.
    Overall, the proposed rule results in annualized cost savings of 
approximately $174 to $194 million per year when discounting at 3% and 
approximately $232 to $262 million per year when discounting at 7%.
    The proposed rule modifies the existing regulatory framework of the 
CCR program with two broad categories of changes that result in impacts 
to the baseline benefits. The first set of changes eliminates or delays 
closure and corrective action requirements for specific units that are 
subject to regulation in the baseline. Specifically, the provision 
rescinding all requirements for CCRMU eliminates the closure and 
corrective action requirements for those units, while the provision 
allowing a permit authority to extend closure timeframes for CCR units 
where CCR is being extracted from the unit for beneficial use during 
closure delays closure for a subset of CCR units. These changes result 
in negative or dis-benefits when compared to the baseline. EPA has 
quantified these dis-benefits for three categories of benefits. These 
three categories are the avoided risk of CCR release events, the 
avoided impairment of human health, and avoided ecological harms. The 
annualized dis-benefits attributable to these provisions are 
approximately $9 to $21 million per year when discounting at 3% and 
approximately $8 to $18 million per year when discounting at 7%.
    The second set of changes encourages the beneficial use of CCR by 
provide permitting flexibilities to encourage extraction of CCR during 
the closure of CCR units, and after closure of CCR units that close 
with waste in place. Extracted CCR can be beneficially used as an 
ingredient in, or substitute for, portland cement. CCR can also be 
beneficially used as a road base or construction fill, where it 
replaces virgin materials such as sand or gravel. The RIA estimates the 
positive annualized benefits associated with increased beneficial use 
of CCR at approximately $4 to $16 million per year when discounting at 
either 3% or 7%.
    Overall, the proposed rule will result in annualized changes in 
benefits of approximately:
     A $5 million decrease when discounting at 3%; and
     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%.

E. What analysis of children's health did we conduct?

    This action is subject to the EPA's Policy on Children's Health 
because the proposal has considerations for human health. However, EPA 
does not believe there are disproportionate risks to children because 
the populations living near CCR disposal facilities do not contain a 
disproportionate number of children relative to national averages. 
Please see the RIA (Section 5.1.2 Human Health Risk Assessment for 
Chronic Exposure Pathways) in the docket.

VI. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is a significant regulatory action as defined under 
section 3(f)(1) of Executive Order 12866. Accordingly, it was submitted 
to the Office of Management and Budget (OMB) for review. Any changes 
made in response to OMB recommendations have been documented in the 
docket. The EPA prepared an analysis of the potential costs and 
benefits associated with this action. This analysis, ``Regulatory 
Impact Analysis; Hazardous and Solid Waste Management System: Disposal 
of Coal Combustion Residuals from Electric Utilities; Legacy/CCRMU 
Amendments'' is available in the docket, and is briefly summarized in 
Unit V. of this proposed rule.

B. Executive Order 14192: Unleashing Prosperity Through Deregulation

    This action is expected to be an Executive Order 14192 deregulatory 
action. This proposed rule is expected to provide burden reduction by 
streamlining and reducing regulatory requirements for owners and 
operators of CCR surface impoundments and CCRMUs.

C. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the PRA. The Information Collection Request (ICR) documents 
that the EPA prepared have been assigned EPA ICR numbers 2609.04 (OMB 
control no. 2050-0223) and 2761.03 (OMB control no. 2050-0231). You can 
find a copy of the ICR in the docket for this rule, and it is briefly 
summarized here.
    ICR number 2609.04 is the base ICR for the CCR program and covers 
all information collection activities required for CCR disposal units 
regulated under the 2015 final rule. ICR number 2761.03 is a temporary 
ICR which EPA requested to cover the information collection activities 
required under the 2024 Legacy final rule. EPA requested this temporary 
ICR due to the concurrent timing of the Legacy rule's finalization and 
the renewal of the base ICR. EPA will submit a request to merge the 
Legacy rule ICR (2761.03) into the base ICR (2609.04) at a later date. 
The information collection requirements are not enforceable until OMB 
approves them.
ICR Number 2609.04
    For ICR 2609.04 (OMB control no. 2050-0223), the prior ICR 
supporting statement had included sections on information collection 
related to beneficial use, even though that ICR estimated zero users 
would demonstrate and keep records of beneficial use. Regardless, ICR 
2609.04 (OMB control no. 2050-0223) has been updated to remove the 
sections on beneficial use information collection which corresponds 
with the proposed requirements of this action.
    Respondents/affected entities: Electric utility facilities and 
independent power producers that fall under the NAICS code 221112 
(Fossil Fuel Electric Power Generation).
    Respondent's obligation to respond: Mandatory under RCRA Subtitle 
D, 40 CFR part 257.
    Estimated number of respondents: 300 coal-fired electric utility 
plants with 723 disposal units. There is no change in number of 
respondents resulting from the proposed rule.
    Frequency of response: Includes one-time, annual, and incidental/
recurring responses.
    Total estimated burden: 173,083 hours (per year). There is no 
change in number of hours from the proposed rule.
    Total estimated cost: $26,168,233 (per year), comprised of 
$10,656,807 in annual labor costs and $15,511,426 in annual operation & 
maintenance costs. There is no change in the annual costs

[[Page 19019]]

per year resulting from the proposed rule.
ICR Number 2761.03
    The changes made for ICR 2761.03 (OMB control no. 2050-0231) 
correspond with facilities no longer needing to complete the Facility 
Evaluation Report, required under 40 CFR 257.73(c) and (d).
    Respondents/affected entities: Electric utility facilities and 
independent power producers that fall under the NAICS code 221112 
(Fossil Fuel Electric Power Generation) and electric utilities and 
independent power producers that fall under the NAICS code 22111 
(Electric Power Generation) whose facilities formerly burned coal to 
produce electricity and disposed of CCR onsite in legacy surface 
impoundments, CCRMU, and CCRMU at other active facilities.
    Respondent's obligation to respond: Mandatory under RCRA Subtitle 
D, 40 CFR part 257.
    Estimated number of respondents: 2,044 coal-fired electric utility. 
This is a reduction from the 2,083 respondents estimated in ICR 2761.03 
based on a more recent accounting of the affected universe. There is no 
change in number of respondents resulting from the proposed rule.
    Frequency of response: Includes one-time, annual, and incidental/
recurring responses.
    Total estimated burden: 211,717 hours (per year). There is a 55,406 
reduction in hours resulting from the proposed rule.
    Total estimated cost: $29,401,324 (per year), comprised of 
$12,610,186 in annual labor costs and $16,791,138 in annual operation & 
maintenance costs. There is a $3,489,105 reduction in costs, including 
$3,136,867 in annual labor costs and $352,238 in annual operation & 
maintenance costs resulting from the proposed rule.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9. Submit your 
comments on the Agency's need for this information, the accuracy of the 
provided burden estimates, any suggested methods for minimizing 
respondent burden, EPA's plan to merge the Legacy rule ICR (2761.03) 
into the base ICR (2609.04), and other aspects of these collections to 
the EPA using the docket identified at the beginning of this rule. The 
EPA will respond to any ICR-related comments in the final rule. You may 
also send your ICR-related comments to OMB's Office of Information and 
Regulatory Affairs using the interface at https://www.reginfo.gov/public/do/PRAMain. Find this information collection by selecting 
``Currently under Review--Open for Public Comments'' or by using the 
search function. OMB must receive comments no later than May 13, 2026.

D. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. In 
making this determination, EPA concludes that the impact of concern for 
this rule is any significant adverse economic impact on small entities 
and that the agency is certifying that this rule will not have a 
significant adverse economic impact on a substantial number of small 
entities because the rule relieves regulatory burden on the small 
entities subject to the rule. This proposed rule is a deregulatory 
action and does not add any additional burden beyond the 2024 Legacy 
Final Rule, while relieving some burdens imposed by that rule, and 
potentially relieving some burdens imposed by the 2015 CCR Final Rule, 
leading to cost savings for small entities. Specific relief to small 
entities includes removal of CCRMU regulations, which affects up to 
seven small entities affected by the 2024 Legacy Final Rule. Other 
relief includes regulatory flexibilities that may apply to Legacy CCR 
surface impoundments, which may affect up to five small entities 
affected by the 2024 Legacy Final Rule, and regulatory flexibilities 
that may apply to units regulated under the 2015 CCR Final Rule. 
Additional information on the cost savings can be found in the 
Regulatory Impact Analysis, which is available in the docket, and is 
summarized in Unit V. of this proposed rule. We have therefore 
concluded that this action will relieve regulatory burden for all 
directly regulated small entities.

E. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. The action imposes no enforceable duty on any state, 
local or Tribal governments or the private sector. This action relieves 
regulatory burden.

F. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

G. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have Tribal implications as specified in 
Executive Order 13175. This action does not impose new requirements on 
Tribal governments. Thus, Executive Order 13175 does not apply to this 
action.

H. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    Executive Order 13045 directs federal agencies to include an 
evaluation of the health and safety effects of the planned regulation 
on children in federal health and safety standards and explain why the 
regulation is preferable to potentially effective and reasonably 
feasible alternatives. This action is not subject to Executive Order 
13045 because the EPA does not believe the environmental health risks 
or safety risks addressed by this action present a disproportionate 
risk to children. EPA does not believe there are disproportionate risks 
to children because the populations living near CCR disposal facilities 
do not contain a disproportionate number of children relative to 
national averages. However, EPA's Policy on Children's Health applies 
to this action. Information on how the Policy was applied is available 
under ``What Analysis of Children's Environmental Health Did We 
Conduct?'' in the Supplementary Information section of this preamble.

I. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution or use of energy. This is a deregulatory action.

J. National Technology Transfer and Advancement Act (NTTAA)

    This rulemaking does not involve technical standards.

List of Subjects in 40 CFR Part 257

    Environmental protection, Beneficial use, Coal combustion products, 
Coal combustion residuals, Coal combustion

[[Page 19020]]

waste, Disposal, Hazardous waste, Landfill, Surface impoundment.

Lee Zeldin,
Administrator.

    For the reasons set out in the preamble, EPA proposes to amend 40 
CFR part 257 as follows:

PART 257--CRITERIA FOR CLASSIFICATION OF SOLID WASTE DISPOSAL 
FACILITIES AND PRACTICES

0
1. The authority citation for part 257 continues to read as follows:

    Authority: 42 U.S.C. 6907(a)(3), 6912(a)(1), 6927, 6944, 6945(a) 
and (d); 33 U.S.C. 1345(d) and (e).

Subpart A--Classification of Solid Waste Disposal Facilities and 
Practices

0
2. Amend Sec.  257.2 by revising the definition ``CCR landfill'' to 
read as follows:


Sec.  257.2  Definitions.

* * * * *
    CCR landfill means an area of land or an excavation that contains 
CCR and which is not a surface impoundment, an underground injection 
well, a salt dome formation, a salt bed formation, an underground or 
surface coal mine, or a cave. For purposes of this subpart, a CCR 
landfill also includes sand and gravel pits and quarries that receive 
CCR, any practice that does not meet the definition of a beneficial use 
of CCR, and any accumulation of CCR on the land that does not meet the 
definition of a CCR storage pile.
* * * * *

Subpart D--Standards for the Disposal of Coal Combustion Residuals 
in Landfills and Surface Impoundments

0
3. Amend Sec.  257.50 by adding paragraphs (j), (k), and (l) to read as 
follows:


Sec.  257.50  Scope and purpose.

* * * * *
    (j) The requirements of this subpart do not apply to CCR dewatering 
structures as defined in Sec.  257.53.
    (k) This subpart does not apply to CCR at cement kilns before use 
as an ingredient in cement manufacturing.
    (l) This subpart does not apply to flue gas desulfurization gypsum 
that is:
    (1) Destined to be applied as an agricultural amendment at 
agronomically appropriate rates, or
    (2) Destined for use as an ingredient in wallboard manufacturing.
0
4. Amend Sec.  257.53 by:
0
a. Revising the definition ``Beneficial use of CCR'';
0
b. Adding in alphabetical order the definition ``CCR dewatering 
structure'';
0
c. Revising the definition ``CCR landfill or landfill'';
0
d. Removing the definition ``CCR pile or pile'';
0
e. Adding in alphabetical order the definition ``CCR storage pile'';
0
f. Revising the definition ``CCR surface impoundment or impoundment''; 
and
0
g. Adding in alphabetical order the definition ``Temporary 
accumulation''.
    The revisions and additions read as follows:


Sec.  257.53  Definitions.

* * * * *
    Beneficial use of CCR means the CCR meets all of the following 
conditions:
    (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; and
    (3) The use of the CCR must meet relevant product specifications, 
regulatory standards or design standards when available, and when such 
standards are not available, the CCR is not used in excess quantities.
* * * * *
    CCR dewatering structure means 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.
* * * * *
    CCR landfill or landfill means an area of land or an excavation 
that contains CCR and which is not a surface impoundment, an 
underground injection well, a salt dome formation, a salt bed 
formation, an underground or surface coal mine, or a cave. For purposes 
of this subpart, a CCR landfill also includes sand and gravel pits and 
quarries that receive CCR, any practice that does not meet the 
definition of a beneficial use of CCR, and any accumulation of CCR on 
the land that does not meet the definition of a CCR storage pile.
* * * * *
    CCR storage pile means any temporary accumulation of solid, non-
flowing CCR placed on the land that is designed and managed to control 
unpermitted releases of CCR to the environment.
* * * * *
    CCR surface impoundment or impoundment means a natural topographic 
depression, man-made excavation, or diked area, designed to hold an 
accumulation of CCR and liquids, and the unit treats, stores, or 
disposes of CCR. A unit meeting the definition of a CCR dewatering 
structure as defined in Sec.  257.53 is not a CCR surface impoundment.
* * * * *
    Temporary accumulation means an accumulation on the land that is 
neither permanent nor indefinite. To demonstrate that the accumulation 
on the land is temporary, the CCR must be removed from the pile at the 
site. The entity engaged in the activity may use ordinary business 
records to demonstrate that the CCR in the pile will be removed 
according to a specific timeline.
* * * * *
0
5. Amend Sec.  257.90 by revising paragraph (b)(2) to read as follows:


Sec.  257.90  Applicability.

* * * * *
    (b) * * *
    (2) New CCR landfills, new CCR surface impoundments, and all 
lateral expansions of CCR units. Prior to initial receipt of CCR by the 
CCR unit, the owner or operator must be in compliance with the 
groundwater monitoring requirements specified in paragraphs (b)(1)(i) 
and (ii) of this section. In addition, prior to initial receipt of CCR, 
the owner or operator of the CCR unit must collect and analyze eight 
independent samples from each well for the parameters listed in 
appendix III and IV to this part to determine background levels for all 
appendix III and IV constituents, and initiate the detection monitoring 
program in Sec.  257.94.
* * * * *
0
6. Amend Sec.  257.94 by revising paragraph (b) to read as follows:


Sec.  257.94  Detection monitoring program.

* * * * *
    (b) Except as provided in paragraph (d) of this section, the 
monitoring frequency for the constituents listed in appendix III to 
this part shall be at least semiannual during the active life of the 
CCR unit and the post-closure period. For existing CCR landfills and 
existing CCR surface impoundments, a minimum of eight independent 
samples from each background and downgradient well must be collected 
and analyzed for the constituents listed in appendix III and IV to this 
part no later than October 17, 2017. For new CCR landfills, new CCR 
surface

[[Page 19021]]

impoundments, and all lateral expansions of CCR units, a minimum of 
eight independent samples for each background well must be collected 
and analyzed for the constituents listed in appendices III and IV to 
this part by the deadline in Sec.  257.90(b)(2).
* * * * *
0
7. Amend Sec.  257.100 by:
0
a. Revising the introductory text of paragraph (g); and
0
b. Adding paragraph (g)(7).
    The revision and addition read as follows:


Sec.  257.100  Inactive CCR surface impoundments and Legacy CCR surface 
impoundments.

* * * * *
    (g) For owners and operators of legacy CCR surface impoundments 
that completed closure of the CCR unit by removal of waste prior to 
Friday, November 8, 2024, no later than Friday, November 8, 2024, 
complete a closure certification that contains the supporting 
information in paragraphs (g)(1) through (6) of this section or by 
[DATE SIX MONTHS AFTER DATE OF PUBLICATION OF THE FINAL RULE IN THE 
FEDERAL REGISTER] complete a closure certification that contains the 
information in paragraph (g)(7) of this section:
* * * * *
    (7) 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. Impacts to groundwater must have been 
considered prior to or as part of the closure. This enforceable 
requirement includes a State or Federal permit, an administrative 
order, or consent order under CERCLA or by an EPA-approved RCRA State 
program.
* * * * *
0
8. Amend Sec.  257.101 by revising paragraph (g) to read as follows:


Sec.  257.101  Closure or retrofit of CCR units.

* * * * *
    (g) Deferral of previous closures of legacy CCR surface 
impoundments. Deferral to permitting for closures conducted under 
substantially equivalent regulatory authority. Notwithstanding the 
provisions of paragraphs (e) and (f) of this section, the owner or 
operator of a legacy CCR surface impoundment need not demonstrate 
compliance with the performance standards in Sec.  257.102(c) or (d) 
provided they demonstrate that the closure of the CCR unit met the 
standards specified in paragraphs (g)(1) through (4) of this section.
    (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 issued on or after October 19, 2015. This 
enforceable requirement includes a State or Federal permit, an 
administrative order, or consent order under CERCLA or by an EPA-
approved RCRA State program.
    (2) The owner or operator of the CCR unit must document that it 
installed a groundwater monitoring system and performed groundwater 
monitoring.
    (3) The owner or operator must include the following statement, 
signed by the owner or operator or an authorized representative, in the 
applicability report for legacy CCR surface impoundments specified in 
Sec.  257.100(f)(1) along with all information required by paragraphs 
(g)(1) through (3) of the section:

    I certify under penalty of law that I have personally examined 
and am familiar with the information submitted in this demonstration 
and all attached documents, and that, based on my inquiry of those 
individuals immediately responsible for obtaining the information, I 
believe that the submitted information is true, accurate, and 
complete. I am aware that there are significant penalties for 
submitting false information, including the possibility of fine and 
imprisonment.

    (4) Closure equivalency determination at permitting. The owner or 
operator must submit the following documentation to the permit 
authority.
    (i) A permit application that contains sufficient information, 
including data on contaminant levels in groundwater, to demonstrate 
that the applicable Sec.  257.102 or Sec.  257.112 standards have been 
met.
    (ii) The permit authority will review the information to determine 
whether the ``equivalency'' of the closure has been successfully 
demonstrated. If the permit authority determines that the closure has 
met the relevant part 257 closure standard, the permit authority will 
issue a permit to require compliance with applicable post-closure 
requirements. If EPA or a Participating State Director determines that 
the closure does not meet the relevant part 257 standard 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 closed unit to achieve compliance with Sec.  257.102 or Sec.  
257.112.
* * * * *
0
9. Add an undesignated center heading and Sec.  257.110 to read as 
follows:

Flexibilities for Owners or Operators of CCR Units Operating Under CCR 
Permits


Sec.  257.110  Groundwater monitoring under a CCR permit authority.

    (a) Applicability. The Participating State Director or EPA, where 
EPA is the permit authority, may elect to establish alternative points 
of compliance, pursuant to this section, for CCR units complying with 
the groundwater monitoring requirements in Sec.  257.91 under a CCR 
permit, in lieu of those in Sec. Sec.  257.91(a)(2), (c)(2), and (d)(1) 
and 257.94(e).
    (1) The owner or operator of a CCR unit must comply with all 
requirements in Sec.  257.91, except as provided for in paragraphs (b) 
through (e) of this section.
    (2) For purposes of this section, point of compliance means the 
vertical surface located hydraulically downgradient of the CCR unit at 
which the owner or operator of the CCR unit must monitor the uppermost 
aquifer [to comply with the detection monitoring program and assessment 
monitoring program in Sec. Sec.  257.94 and 257.95 or Sec.  257.111. 
The vertical surface extends down into the uppermost aquifer.
    (b) Establishing alternative points of compliance. Notwithstanding 
the requirement to monitor the waste boundary in Sec.  257.91(a)(2), 
(c)(2), and (d)(1), the permit authority, may establish an alternative 
point of compliance to be used in lieu of the waste boundary of the CCR 
unit in accordance with the requirements of this paragraph (b).
    (1) The alternative point of compliance must be no more than 150 
meters from the waste boundary and located at the facility.
    (2) The permit authority, may only establish an alternative point 
of compliance if the Participating State Director or EPA determines, 
based on a demonstration by the owner or operator, that the point of 
compliance, together with the location characteristics, will:
    (i) Not materially delay detection of any statistically significant 
amounts of any of the constituents listed in appendices III and IV to 
this part from that CCR unit; and
    (ii) Will minimize the migration of any of those constituents from 
that CCR unit to the uppermost aquifer during the active life of the 
CCR unit and the post-closure care period.
    (3) In determining the alternative point of compliance, the permit 
authority, must analyze and consider the following factors:

[[Page 19022]]

    (i) Compliance with the location restrictions specified in 
Sec. Sec.  257.61 through 257.64;
    (ii) Compliance with the corrective action procedures specified in 
Sec. Sec.  257.96 through 257.98;
    (iii) The hydrogeological characteristics of the facility and 
surrounding land, including any natural attenuation and dilution 
characteristics of the aquifer;
    (iv) The quantity, quality, and direction of flow of groundwater 
underlying the facility;
    (v) The proximity and withdrawal rates of groundwater users;
    (vi) The availability of alternative drinking water supplies;
    (vii) The existing quality of the groundwater, including other 
sources of contamination and their cumulative impacts on the 
groundwater;
    (viii) The volume and physical and chemical characteristics of the 
leachate; and
    (ix) Public health, safety, and welfare effects.
    (c) Performance standard. When establishing the alternative point 
of compliance under paragraph (b) of this section, the permit 
authority, must ensure the groundwater monitoring system accurately 
represents the quality of groundwater passing the CCR unit. The 
downgradient monitoring system must be installed at the point of 
compliance specified by paragraph (b), that ensures detection of 
groundwater contamination in the uppermost aquifer. All potential 
contaminant pathways must be monitored.
    (d) Multiunit groundwater monitoring systems. Notwithstanding the 
provisions at Sec.  257.91(d)(1), the permit authority, may establish 
alternative points of compliance pursuant to paragraph (b) of this 
section for multiunit groundwater monitoring systems. The multiunit 
groundwater monitoring system must be equally as capable of detecting 
monitored constituents from the CCR unit as the individual groundwater 
monitoring system established in accordance with this subpart based on 
the following factors:
    (1) Number, spacing and orientation of each CCR unit;
    (2) Hydrogeologic setting;
    (3) Site history; and
    (4) Engineering design of the CCR unit.
    (e) Detection and assessment monitoring programs. When the permit 
authority, has established an alternative point of compliance in lieu 
of the waste boundary, the owner or operator of the CCR unit(s) must 
comply with the detection monitoring program and assessment monitoring 
program requirements in Sec. Sec.  257.94 through 257.95 but must 
substitute the established alternative point of compliance for all 
requirements associated with the monitoring wells at the waste 
boundary.
    (f) Recordkeeping, notification, and internet requirements. The 
owner or operator must comply with the applicable recordkeeping 
requirements specified in Sec.  257.105(h), notification requirements 
specified in Sec.  257.106(h), and internet requirements specified in 
Sec.  257.107(h).
0
10. Add Sec.  257.111 to read as follows:


Sec.  257.111  Alternative groundwater protection standards for 
corrective action under a CCR permit authority.

    (a) Applicability. In lieu of the groundwater protection standards 
in Sec.  257.95(h)(2), the Participating State Director or EPA, where 
EPA is the permit authority, may elect to establish alternative 
groundwater protections standards as provided in this section.
    (b) Alternative groundwater protection standards. Notwithstanding 
the groundwater protection standards in Sec.  257.95(h)(2), for 
constituents for which an MCL has not been established under the 
regulations referenced in Sec.  257.95(h)(1), the permit authority, may 
establish alternative groundwater protection standards. These 
groundwater protection standards shall be appropriate health-based 
levels that satisfy the following criteria:
    (1) The level is derived in a manner consistent with Agency 
guidelines for assessing the health risks of environmental pollutants, 
such as the Guidelines for Mutagenicity Risk Assessment, Supplementary 
Guidance for Conducting Health Risk Assessment of Chemical Mixtures; 
the Guidelines for Developmental Toxicity Risk Assessment; and the 
Guidelines for Carcinogen Risk Assessment;
    (2) For carcinogens, the level represents a concentration 
associated with an excess lifetime cancer risk level, due to continuous 
lifetime exposure, within the 1 x 10-4 to 1 x 
10-6 range; and
    (3) For systemic toxicants, the level represents a concentration to 
which the human population, including sensitive subgroups, could be 
exposed to on a daily basis that is likely to be without appreciable 
risk of deleterious effects during a lifetime. For purposes of this 
subpart, systemic toxicants include toxic chemicals that cause effects 
other than cancer or mutation.
    (c) Permit authority considerations. In establishing groundwater 
protection standards under paragraph (b) of this section, the 
Participating State Director or EPA, where EPA is the permit authority, 
must consider the following:
    (1) The presence and concentrations of other contaminants in the 
groundwater;
    (2) Exposure threats to sensitive environmental receptors; and
    (3) Other site-specific exposure or potential exposure to 
groundwater.
    (d) Groundwater monitoring and corrective action annual report. The 
owner or operator must indicate the use of alternative groundwater 
protection standards in the annual groundwater monitoring report 
required at Sec.  257.90(e) and include the specific groundwater 
protection standard for each constituent.
    (e) Recordkeeping, notification, and internet requirements. The 
owner or operator must comply with the applicable recordkeeping 
requirements specified in Sec.  257.105(h), notification requirements 
specified in Sec.  257.106(h), and internet requirements specified in 
Sec.  257. 107(h).
0
11. Add Sec.  257.112 to read as follows:


Sec.  257.112  Closure method under a CCR permit authority.

    (a) Applicability. The Participating State Director or EPA, where 
EPA is the permit authority, may elect to use the following closure 
criteria when approving CCR unit closure plans in lieu of those in 
Sec.  257.102(c) and (d).
    (b) Closure method. Notwithstanding Sec.  257.102(c) and (d), the 
permit authority, may permit the closure of a unit under alternative 
performance standards provided the permit authority assesses the 
closure and concludes that closure in accordance with the alternative 
performance standards will result in no reasonable probability of 
adverse effects to human health and the environment during the active 
life of the CCR unit and the post-closure care period. This assessment 
must be based upon all of the following criteria:
    (1) A site-specific conceptual site model and risk assessment of 
the location in which the CCR unit is located. This assessment must 
include field collected measurements, sampling, and analysis of 
physical, chemical, and biological processes affecting contaminant fate 
and transport, including a minimum, the information necessary to 
evaluate or interpret the effects of the following properties or 
processes on contaminant fate and transport:
    (i) Aquifer characteristics, including hydraulic conductivity, 
hydraulic gradient, effective porosity, aquifer thickness, degree of 
saturation, stratigraphy, degree of fracturing and secondary porosity 
of soils and bedrock, aquifer heterogeneity, groundwater

[[Page 19023]]

discharge, and groundwater recharge areas;
    (ii) Waste characteristics, including quantity, type and origin;
    (iii) Climatic conditions, including annual precipitation, leachate 
generation estimates and effects on leachate quality;
    (iv) Leachate characteristics, including leachate composition, 
solubility, density, the presence of immiscible constituents, Eh and 
pH; and
    (v) Engineered controls, including but not limited to liners, cover 
systems, and aquifer controls (e.g., lowering the water table). These 
must be evaluated under design and failure conditions to estimate their 
long-term residual performance.
    (2) Contaminant fate and transport predictions that maximize the 
contaminant migration and consider impacts on human health and the 
environment.
    (3) The identification, proximity, and potential current and future 
pathways of exposure to nearby human and ecological receptors. The 
assessment must consider current and future land use when evaluating 
the potential exposure pathways. If complete pathways are identified, 
the assessment must include a plan to mitigate potential exposure.
    (c) Recordkeeping, notification, and internet requirements. The 
owner or operator must comply with the applicable recordkeeping 
requirements specified in Sec.  257.105(i), notification requirements 
specified in Sec.  257.106(i), and internet requirements specified in 
Sec.  257.107(i).
0
12. Add Sec.  257.113 to read as follows:


Sec.  257.113  Closure completion timeframes under a CCR permit 
authority.

    (a) Applicability. The Participating State Director or EPA, where 
EPA is the permit authority, may establish the closure completion 
timeframes for CCR units in lieu of those in Sec.  257.102(f)(1) and 
(2).
    (b) Extraction of CCR during closure. Notwithstanding Sec.  
257.102(f)(1) and (2), for closure with extraction of CCR for 
beneficial use as a component of the overall closure method, the permit 
authority, may extend the timeframe for completing closure of a CCR 
unit specified in Sec.  257.102(f) only if the permit authority finds, 
based on a demonstration by the owner or operator, that the extended 
timeframe will pose no reasonable probability of adverse effects on 
health or the environment. The assessment must be based upon all of the 
following criteria:
    (1) Measures for major slope stability are in place to prevent the 
sloughing or movement of the unit during the closure period;
    (2) The extraction of CCR and closure must be completed consistent 
with recognized and generally accepted good engineering practices;
    (3) Potential risks to human health and the environment during 
closure of the unit are adequately mitigated; and
    (4) The facility is in substantial compliance with all other 
requirements of this subpart, including the requirements to conduct 
groundwater monitoring and any necessary corrective action.
    (c) Closure plan. The owner or operator must submit an updated 
closure plan pursuant to Sec.  257.102(b)(3).
    (d) Ongoing closure. The owner or operator must proceed with 
closure activities of any portion of the CCR unit that is not related 
to the extraction of CCR for beneficial use to the extent possible 
within the specified timeframes of Sec.  257.102.
    (e) Recordkeeping, notification, and internet requirements. The 
owner or operator must comply with the applicable recordkeeping 
requirements specified in Sec.  257.105(i), notification requirements 
specified in Sec.  257.106(i), and internet requirements specified in 
Sec.  257.107(i).
0
13. Add Sec.  257.114 to read as follows:


Sec.  257.114  Post-closure care under a CCR permit authority.

    (a) Applicability. The Participating State Director or EPA, where 
EPA is the permit authority, may allow for extraction of CCR from a 
closed CCR unit during the post-closure care period in accordance with 
this section.
    (b) Extraction of CCR during post-closure care. The permit 
authority may allow the owner or operator of a closed CCR unit to 
extract CCR for beneficial use during the post-closure care period only 
if the permit authority finds, based on a demonstration by the owner or 
operator, that any extraction of CCR for beneficial use will not pose a 
reasonable probability of adverse effects to human health and the 
environment. The assessment must be based upon all of the following 
criteria:
    (1) The extraction of CCR for beneficial use must be completed 
consistent with recognized and generally accepted good engineering 
practices;
    (2) Potential risks to human health and the environment during 
post-closure are adequately mitigated; and
    (3) The facility is in substantial compliance with all other 
requirements of this subpart, including the requirements to conduct 
post-closure care, groundwater monitoring, and any necessary corrective 
action.
    (c) Recordkeeping, notification, and internet requirements. The 
owner or operator must comply with the applicable recordkeeping 
requirements specified in Sec.  257.105(i), notification requirements 
specified in Sec.  257.106(i), and internet requirements specified in 
Sec.  257.107(i).

[FR Doc. 2026-07061 Filed 4-10-26; 8:45 am]
BILLING CODE 6560-50-P