Proposed Rule2025-22553
No-Migration Variance From Land Disposal Restrictions for Clean Harbors Lone Mountain, Oklahoma
Primary source
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Published
December 11, 2025
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to grant, with conditions, no-migration variances for nine categories/ groups of wastes, containing up to a combined 100 temporary disposal units ("put piles") at any one time, from the Resource Conservation and Recovery Act (RCRA) Land Disposal Restrictions (LDR) standards at Clean Harbors' Lone Mountain (Clean Harbors) commercial treatment, storage and disposal facility (TSDF) in Waynoka, Oklahoma. These variances will allow Clean Harbors to temporarily store treated hazardous wastes that are awaiting LDR compliance verification in put piles within its Subtitle C (hazardous waste) landfill. The petitioner demonstrated, to a reasonable degree of certainty, that there will be no migration of hazardous constituents from the put piles for as long as the wastes remain hazardous. Additionally, once LDR compliance is verified, the put piles will be disposed within the onsite RCRA hazardous waste landfill area and will be subject to the conditions set out in the Compliance Monitoring Plan section of this document.
Full Text
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<title>Federal Register, Volume 90 Issue 236 (Thursday, December 11, 2025)</title>
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[Federal Register Volume 90, Number 236 (Thursday, December 11, 2025)]
[Proposed Rules]
[Pages 57436-57442]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-22553]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 248
[EPA-R06-RCRA-2025-3129; FRL-13097-01-R6]
No-Migration Variance From Land Disposal Restrictions for Clean
Harbors Lone Mountain, Oklahoma
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of proposal to grant.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
grant, with conditions, no-migration variances for nine categories/
groups of wastes, containing up to a combined 100 temporary disposal
units (``put piles'') at any one time, from the Resource Conservation
and Recovery Act (RCRA) Land Disposal Restrictions (LDR) standards at
Clean Harbors' Lone Mountain (Clean Harbors) commercial treatment,
storage and disposal facility (TSDF) in Waynoka, Oklahoma. These
variances will allow Clean Harbors to temporarily store treated
hazardous wastes that are awaiting LDR compliance verification in put
piles within its Subtitle C (hazardous waste) landfill. The petitioner
demonstrated, to a reasonable degree of certainty, that there will be
no migration of hazardous constituents from the put piles for as long
as the wastes remain hazardous. Additionally, once LDR compliance is
verified, the put piles will be disposed within the onsite RCRA
hazardous waste landfill area and will be subject to the conditions set
out in the Compliance Monitoring Plan section of this document.
DATES: Comments must be received on or before January 12, 2026.
ADDRESSES: You may send comments, identified by Docket ID No. EPA-R06-
RCRA-2025-3129, by any of the following methods:
<bullet> Federal eRulemaking Portal: <a href="https://www.regulations.gov">https://www.regulations.gov</a>
(our preferred method). Follow the online instructions for submitting
comments.
<bullet> Email: <a href="/cdn-cgi/l/email-protection#83cef6f0f7e2e5e2ade4ecefe2eec3e6f3e2ade4ecf5"><span class="__cf_email__" data-cfemail="de93abadaabfb8bff0b9b1b2bfb39ebbaebff0b9b1a8">[email protected]</span></a>. Include Docket ID No. EPA-
R06-RCRA-2025-3129 in the subject line of the message.
<bullet> Courier/Hand Delivery: Golam Mustafa, Land, Chemicals and
Redevelopment Division, EPA Region 6, 1201 Elm Street, Dallas, Texas
75270, Mail Code: R6LCR-RP, telephone number: (214) 665-6576. Courier
or hand deliveries are only accepted during the Regional Office's
normal hours of operation. The public is advised to call in advance to
verify the business hours. Special arrangements should be made of
deliveries of boxed information.
<bullet> Instructions: All submissions must include the Docket ID
No. EPA-R06-RCRA-2025-3129 for this proposed approval. Comments
received may be posted without change to <a href="https://www.regulations.gov">https://www.regulations.gov</a>,
including any personal information provided. For detailed instructions
on sending comments and additional information, see the ``Public
Participation'' heading of the SUPPLEMENTARY INFORMATION section of
this document.
FOR FURTHER INFORMATION CONTACT: Golam Mustafa, Land, Chemicals and
Redevelopment Division, EPA Region 6, 1201 Elm Street, Dallas, Texas
75270, Mail Code: R6LCR-RP, telephone number: (214) 665-6576; and
email: <a href="/cdn-cgi/l/email-protection#a8e5dddbdcc9cec986cfc7c4c9c5e8cdd8c986cfc7de"><span class="__cf_email__" data-cfemail="94d9e1e7e0f5f2f5baf3fbf8f5f9d4f1e4f5baf3fbe2">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
I. Public Participation
A. Docket
EPA has established a docket for this action under Docket ID No.
EPA-R06-RCRA-2025-3129. All documents in the docket are listed in the
<a href="https://www.regulations.gov">https://www.regulations.gov</a> index.
B. Written Comments
Submit your comments, identified by Docket ID No. EPA-R06-RCRA-
2025-3129, at <a href="https://www.regulations.gov">https://www.regulations.gov</a> (our preferred method), or
the other methods identified in the ADDRESSES section. Once submitted,
comments
[[Page 57437]]
cannot be edited or removed from the docket. EPA may publish any
comment received to its public docket. Do not submit electronically any
information you consider to be Confidential Business Information (CBI)
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). For additional submission methods, the full EPA public comment
policy, information about CBI or multimedia submissions, and general
guidance on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
C. Submitting CBI
Do not submit information that you consider to be CBI
electronically through <a href="https://www.regulations.gov">https://www.regulations.gov</a> or email. Send or
deliver information identified as CBI to only the following address:
RCRA Document Control Officer, La Gayla Johnson, Office of Regional
Counsel, EPA Region 6, 1201 Elm Street, Dallas, Texas 75270, Mail Code:
R06-ORC-DRCGLCB-FIAB; telephone number: (214) 665-7517; and email:
<a href="/cdn-cgi/l/email-protection#f8b29790968b9796d694999f99819499b89d8899d69f978e"><span class="__cf_email__" data-cfemail="074d686f69746869296b6660667e6b664762776629606871">[email protected]</span></a>.
Attn: Docket ID No. EPA-R06-RCRA-2025-3129.
Clearly mark the part or all of the information that you claim to
be CBI. For CBI information on a disk or CD-ROM that you mail to EPA,
mark the outside of the disk or CD-ROM as CBI and then identify
electronically within the disk or CD-ROM the specific information that
is claimed as CBI. In addition to one complete version of the comment
that includes information claimed as CBI, a copy of the comment that
does not contain the information claimed as CBI must be submitted for
inclusion in the public docket. If you submit a CD-ROM or disk that
does not contain CBI, mark the outside of the disk or CD-ROM to clearly
indicate that it does not contain CBI. Information marked as CBI will
not be disclosed except in accordance with procedures set forth in 40
Code of Federal Regulations (CFR) Part 2.
II. General Information
A. Does this document apply to me?
This action applies only to Clean Harbors' Lone Mountain facility
(Clean Harbors) located in Waynoka, Oklahoma.
B. What action is the Agency taking?
On November 29, 2023, Clean Harbors submitted a no-migration
variance (NMV) petition, in accordance with 40 CFR 268.6, seeking an
exemption from the Land Disposal Restrictions (LDR) prohibition on land
placement of hazardous waste that does not meet the prescribed LDR
standards of 40 CFR 268.40 for temporary piles of treated waste,
referred to as put piles, placed within the boundary of a RCRA-
permitted hazardous waste landfill. Because the petition demonstrated
to a reasonable degree of certainty that, for as long as the wastes
remain hazardous, there will be no migration of hazardous constituents
from the put piles, EPA proposes to grant, with conditions, Clean
Harbors' variance from the LDR prohibition for up to a combined 100 put
piles at any one time for the nine categories/groups of wastes
identified in the Waste Characterization section of this proposal. If
granted, the term of this NMV shall be no longer than the term of the
RCRA Subtitle C permit for the permitted landfill.
C. What is the Agency's authority for taking this action?
Sections 3004(d) through (g) of the Resource Conservation and
Recovery Act (RCRA), 42 U.S.C. 6294(d)-(g), prohibit the land disposal
of hazardous wastes unless such wastes meet the LDR treatment standards
(``treatment standards'') established by EPA (``Agency'').
However, RCRA 3004(d)(1),\1\ and its implementing regulations found
at 40 CFR 268.6, provide an option for land disposal of hazardous waste
that does not meet the applicable treatment standards where EPA has
approved an NMV petition. Specifically, 40 CFR 268.6(a) describes the
components that a demonstration of no migration must address; 268.6(b)
specifies certain criteria that must be satisfied for that
demonstration, and 268.6(c) describes the monitoring program that will
be used to verify that the conditions of the NMV are being met.
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\1\ RCRA 3004(d)(1)(c) states: ``. . . For the purposes of this
paragraph, a method of land disposal may not be determined to be
protective of human health and the environment for a hazardous waste
referred to in paragraph (2) . . . unless, upon application by an
interested person, it has been demonstrated to the Administrator, to
a reasonable degree of certainty, that there will be no migration of
hazardous constituents from the disposal unit or injection zone for
as long as the wastes remain hazardous.''
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III. Background
A. No-Migration Variances and Guidance
An NMV is a formal decision that can be rendered by the EPA in
response to a petition filed with the Agency to allow land disposal
within a particular disposal unit of specific prohibited waste when it
has been demonstrated, ``to a reasonable degree of certainty, that
there will be no migration of hazardous constituents from the disposal
unit . . . for as long as the wastes remain hazardous.'' \2\ It must be
demonstrated, to a reasonable degree of certainty, that hazardous
constituents will not exceed Agency-approved human health-based levels
(or environmentally protective levels, if they are appropriate) beyond
the boundary of the disposal unit.\3\ In most cases, the disposal unit
boundary is defined as the outermost limit of engineered components.\4\
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\2\ See 51 FR at 40578, November 7, 1986.
\3\ 57 FR 35941, August 11, 1992.
\4\ Id.
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Approval of an NMV petition is delegated to the EPA Regional
Administrator for the EPA Region in which the waste management unit is
located. States are not authorized to implement the NMV authority;
however, the EPA consulted with Oklahoma prior to proposing to grant
this NMV. The final decision will be published in the Federal Register.
If granted, the term of an NMV may be no longer than the term of the
existing RCRA Subtitle C permit for the landfill. Any petitions to
renew an NMV must undergo notice and comment procedures. An NMV that
has been issued can be revoked for cause, including any migration of
hazardous constituents.
The regulatory requirements for an NMV under the RCRA LDRs were
codified in 40 CFR 268.6 in 1986,\5\ and EPA issued guidance on these
requirements in 1992. The 1992 guidance is applicable to landfills,
surface impoundments, and waste piles. While the 1992 guidance
acknowledged temporary placement of waste under an approved NMV, it did
not address the issue of temporary placement of treated wastes in put
piles while awaiting LDR compliance verification (or retreatment)
within the boundary of a RCRA-permitted Subtitle C (hazardous waste)
landfill. After a put pile is confirmed to meet the LDR standards, it
is moved to the ``working face'' \6\ of the landfill for
[[Page 57438]]
final disposal; however, if there is an exceedance of an LDR standard,
the put pile is returned to the treatment process for further
treatment.
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\5\ 51 FR 40572, November 7, 1986.
\6\ The working face of a landfill is the area within a specific
cell where waste is currently being placed and compacted. It is the
designated section where waste is unloaded, and daily cover is
applied at the end of each working day.
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Hazardous waste in a put pile either must meet the LDR standards or
have an approved NMV. To provide guidance specific to this
circumstance, the EPA issued ``Information for Petitioners Seeking a
No-Migration Variance Under the RCRA Land Disposal Restrictions for
Temporary Placement of Treated Hazardous Waste Within a Permitted
Subtitle C Landfill'' (88 FR 10894, February 22, 2023). This
information (i.e., the ``2023 Guidance'') is posted online at <a href="https://rcrapublic.epa.gov/files/14952.pdf">https://rcrapublic.epa.gov/files/14952.pdf</a>.
The 2023 Guidance acknowledges the need for unique considerations
when a no migration demonstration for put piles occurs within a
Subtitle C landfill prior to permanent disposal in the landfill. ``EPA
expects that petitioners will be able to take advantage of existing
facility information (e.g., existing monitoring, inspections,
engineered barriers, waste analyses), where appropriate, as part of any
demonstration . . . For example, the use of temporary barriers, such as
plastic covers above and below the piles; visual monitoring, prompt
responses to possible releases, and good housekeeping practices that
ensure the treated waste remains in the pile during the temporary
storage period would be elements to consider. Attributes of the
permitted landfill cell (e.g., design, existing controls, monitoring)
in which the pile or piles are located should also be considered to the
extent that they support the demonstration criteria being applied to
the piles themselves.''
40 CFR 268.6(e) acknowledges the potential for post-approval
changes in conditions at the no migration unit(s) and/or the
environment around the no migration unit(s). For the purpose of these
put pile variances, all changes that significantly depart from the
conditions described in the variances and affect the potential for
migration of hazardous constituents from the put piles must be reported
to the Region 6 Administrator as follows:
1. If Clean Harbors plans to make changes to the unit(s)' design,
construction, or operation, such a change must be proposed, in writing,
and include a demonstration to the Region 6 Administrator at least 30
days prior to making the change. The Region 6 Administrator will
determine whether the proposed change invalidates the terms of the
approved variance and will determine the appropriate response. A
proposed change must first be approved by the Region 6 Administrator
before taking any action.
2. If Clean Harbors discovers a site condition in the petition that
does not occur as modeled or predicted, this change must be reported,
in writing, to the Region 6 Administrator within 10 days of discovery.
The Region 6 Administrator will determine whether the reported change
from the terms of the approved variance requires further action.
B. Clean Harbors' Petition for No Migration Variances
On November 29, 2023, Clean Harbors' Lone Mountain facility in
Waynoka, Oklahoma, submitted an NMV petition to the EPA seeking an
exemption from the LDR prohibition on placing hazardous waste on the
ground, if that waste does not meet the prescribed LDR standards of 40
CFR 268.40, by demonstrating that for as long as the waste remains
hazardous, there will be no migration of hazardous constituents from
the disposal units. Clean Harbors' no migration demonstration applies
to nine categories/groups of wastes stored in up to a combined 100 put
piles at any one time located within the facility's Subtitle C Landfill
cell, known as ``Cell 15.'' If Clean Harbors anticipates needing to
exceed 100 put piles at any one time, it must request approval from EPA
Region 6 prior to creating new put piles. Clean Harbors also requested
that this variance proactively apply to future put piles of identical
waste characteristics that would be staged in a future proposed and
permitted Subtitle C landfill cell, known as ``Cell 16.''
While this Notice of Proposal to Grant applies only to those put
piles placed within existing Landfill Cell 15, upon permit approval of
Cell 16, Clean Harbors may submit to the Agency, an addendum to this
petition to expand this NMV and all of its conditions and requirements,
for the put piles located within the new landfill cell if:
1. Clean Harbors is in compliance with the approved NMV,
2. The new landfill cell uses the same disposal unit engineered
controls (e.g., landfill cell interior berms for run-on and run-off
control) as approved in this variance,
3. The duration of temporary placement remains at six (6) months or
less and complies with the conditions established herein,
4. The waste categories remain the same, and
5. The monitoring program (e.g., groundwater monitoring) is
expanded to include the new landfill cell.
In response to EPA requests following the original November 2023
submission, Clean Harbors provided supplemental information for the
Agency's evaluation of Clean Harbors' no-migration demonstration. The
original petition and associated responses to Agency information
requests (together referred to as ``the petition'') can be found in the
docket (EPA-R06-RCRA-2025-3129).
Clean Harbors' petition includes the following components: (a)
facility description, (b) site characterization/unit description, (c)
identification and characterization of the affected wastes, (d)
disposal unit engineered controls, (e) duration of temporary staging,
(f) uncertainty analysis, (g) monitoring program, and (h) documented
compliance with other laws. These are discussed below.
IV. Basis for the EPA's Proposed Determination
A. Components of the Petition
1. Facility Description
Clean Harbors' Lone Mountain facility (EPA ID Number: OKD065438376)
is located 14 miles southeast of the town of Waynoka. The mean annual
precipitation in the region is approximately 28 inches and 11 inches
for rain and snow, respectively. The permitted facility, which covers
an area of approximately 560 acres, is expected to be in operation for
more than ten years from the date of this notice. A RCRA Part B Permit
(hazardous waste permit) was issued by the Oklahoma Department of
Environmental Quality (ODEQ). The currently approved RCRA permit was
signed on April 2, 2011, for a 10-year term, and then administratively
continued.
Clean Harbors' hazardous waste permit authorizes the facility to
manage liquid, solid, or semisolid hazardous waste and non-hazardous
industrial waste. The facility has 15 hazardous waste landfill cells.
Waste treatment services provided at the facility include
solidification, stabilization, and macro/microencapsulation of
hazardous waste. Solid, liquid, and sludge wastes are accepted in
containerized or bulk loads (e.g., roll-off containers); however, the
wastes that would be covered under this NMV are generally received as
bulk loads.
2. Site Characterization/Unit Description
All put piles are temporarily stored in Landfill Cell 15 until LDR
compliance has been confirmed. LDR-compliant
[[Page 57439]]
piles are then moved to the working face of Landfill Cell 15 after
verification of successful treatment. Put piles that fail to meet LDR
standards are retreated and subsequently returned as a put pile to
landfill Cell 15. This variance, if approved, will apply to put piles
of the nine waste categories/groups and not to Landfill Cell 15. As
stated in the 2023 guidance, where multiple piles contain the same or
similar wastes, the petition can address these units as a group where
such piles are effectively being managed as a single unit. As such, the
Agency proposes that this NMV apply to the put piles containing the
nine categories/groups described in the Waste Characterization section
below; however, each put pile within each category/group will be
assigned its own unit boundary.
Each put pile measuring approximately 35-cubic yards is placed on a
polyethylene barrier sheet (20-millimeter (mil) minimum thickness)
within landfill Cell 15. Because wastes are treated and presumed to
meet LDR standards prior to placement in Landfill Cell 15, and storage
in the petitioned units is temporary, the Agency herein proposes to
establish unit boundaries (i.e., points of compliance for no-migration
purposes) for each of the put piles to account for existing landfill
controls and appropriate deviations from the waste pile liner design
standards of 40 CFR 264.251.
The Agency proposes that each put pile boundary extend vertically
one inch below the 20-mil thick polyethylene liner and laterally one
foot short of the outermost surface edges of the 20-mil thick
polyethylene liner. Air dispersion compliance will be demonstrated at
the outer thickness of the Posi-Shell[supreg] liner, described in the
Covers section, below.
3. Waste Characterization
In accordance with 40 CFR 268.6(a)(1), Clean Harbors indicated that
the following nine categories/groups of hazardous wastes and their
underlying hazardous constituents (UHCs) found at 40 CFR 268.48 could
be temporarily placed in the put piles in Landfill Cell 15 after
treatment to meet LDR standards: (1) general metals (D001, D002, D004
through D011, K046, F006, F019, F039 and U051); (2) cyanide/sulfide
with metals (D001 through D011, F006 through F012, F019, K052 and
P106); (3) cyanide/sulfide (D001 through D011, F006 through F012, F019,
P106 and U135); (4) high-chromium wastes (D001 through D011, F006 and
F019); (5) high arsenic wastes (D004, D005, D006, D008, D009, D010,
P011 and P012); (6) oxidizers with metals (D001, D002, D003, D005,
D007, D008, D011 and K088); (7) acids with metals (D001, D002, D004
through D011, K061, K062, F006, U204 and U134); (8) bases with metals
(D002 through D011, D028, K061, F006 through F008, F019, F035, P106,
U144, U151, U188 and U210); and (9) waste certified by generators to
meet all or some LDR treatment standards (referenced as CBPR by Clean
Harbors; codes vary and include K052, F020 and U210).
Appropriate and adequate sampling and analysis of both incoming
hazardous wastes and treated hazardous wastes are essential to precise
waste characterization for accurate creation of treatment protocols or
``recipes,'' and ultimately, confirmation of treatment effectiveness/
LDR compliance. These are discussed in Clean Harbors' Waste Analysis
Plan (WAP), approved by ODEQ in February 2010, and included in the
docket for this notice and available, at the time of this notice, on
the ODEQ website at <a href="https://oklahoma.gov/deq/divisions/land-protection/waste-management/waste-management-facilities/clean-harbors-lone.html">https://oklahoma.gov/deq/divisions/land-protection/waste-management/waste-management-facilities/clean-harbors-lone.html</a>.
The following generalized summary of waste characterization (also
referred to as a fingerprint analysis), waste treatment, and
verification of effective treatment/LDR compliance is extracted from
the Clean Harbors' WAP for incoming bulk loads of hazardous waste.
Incoming bulk wastes undergo a fingerprint analysis that includes eight
basic screening procedures (physical appearance, pH, specific gravity,
reactive cyanides, reactive sulfides, water reactivity, ignitability,
and halogen organic compound content) to provide a general waste
characterization for appropriate treatment, storage, or disposal.
Additional analyses are performed, as appropriate, to ensure adequate
waste characterization. After characterization, bulk hazardous wastes
are treated in stabilization tanks to reduce the hazardousness of the
wastes, make them safter to dispose, and/or reduce the volume of the
wastes. Waste treatment processes include stabilization, blending, and
the LDR technology standards for chemical oxidation (CHOXD),
neutralization (NEUTR), chromium or chemical reduction (CHRED), and
deactivation (DEACT). If stabilization is performed, any combination of
the following reagents may be used to prevent leaching: cement kiln
dust, water, calcium polysulfide, lime, caustic, fly ash, portland
cement, clay, ferrous sulfate, sodium hypochlorite, oxidizer soak, and
acid.
Post-treatment, samples are collected directly from the
stabilization tank and a paint filter test is performed to ensure that
all free liquids have chemically reacted, and the mixture is suitable
for disposal in the landfill. Treated batches are subsequently sampled
and analyzed for LDR compliance pursuant to the WAP. The treated wastes
are then moved to a put pile within a temporary staging area in
Landfill Cell 15 while curing and awaiting LDR compliance confirmatory
sampling. Section 4.2.2 of the WAP defines how sampling of the waste
piles for LDR compliance must be performed.
4. Uncertainty Analysis
40 CFR 268.6(b)(5) requires the petitioner to include an analysis
to identify and quantify any aspects of the demonstration that
contribute significantly to uncertainty. The analysis must include an
evaluation of the consequences of predictable future events, including,
but not limited to, earthquakes, floods, severe storm events, droughts,
or other natural phenomena. The Agency accepts Clean Harbors'
uncertainty analysis as presented in the petition located in the
docket.
5. No-Migration Demonstration
The bases for EPA's proposed conclusion that Clean Harbors
demonstrated to a reasonable degree of certainty that no hazardous
constituents will migrate from the put piles for as long as the wastes
remain hazardous are discussed in this section. Although wastes are
treated with the intent of meeting the RCRA LDR standards prior to
being placed in put piles, the conditions established in this NMV are a
safeguard to ensure that if a put pile does not meet LDR standards and
must be retreated, hazardous constituents will not migrate beyond the
boundary of the put pile. This NMV is conditioned upon the temporary
nature of the put piles within Landfill Cell 15 and is intended for
situations where the put piles are used as part of an overall strategy
to confirm consistent and compliant treatment that meets the applicable
LDR treatment standards.
Where reasonable, the Agency took into consideration existing
landfill design and operating requirements (40 CFR 264.301) that
include run-on and run-off controls to prevent the migration of
hazardous constituents beyond the designated unit boundary. Additional
information including monitoring data and discussions regarding the
temporary nature of these put piles (i.e., duration of storage),
testing for verification of treatment effectiveness, retreatment
[[Page 57440]]
protocols and engineered controls, as referenced in this section, is
available in the petition or supplemental information in the RCRA
regulatory docket for this document.
i. Treatment Effectiveness
As required by 40 CFR 268.6(a)(2), Clean Harbors characterizes the
subject wastes, post-treatment, to determine if LDR standards were met.
Specifics on sampling protocols can be found in the WAP. Analytical
data were provided in non-sequential order in tables A-2 (inorganic
constituents) and A-3 (organic constituents) for January 2022 through
October 2023 for each category of hazardous waste identified in the
petition in the docket for today's notice. Analyses were performed for
compliance with the 40 CFR 268.48 Universal Treatment Standards (UTS)
for all UHCs, including antimony (Sb), arsenic (As), barium (Ba),
beryllium (Be), cadmium (Cd), chromium (Cr), lead (Pb), nickel (Ni),
selenium (Se), silver (Ag), thallium (Tl), vanadium (V), zinc (Zn),
mercury (Hg), sulfides (S), and cyanides (CN).
Clean Harbors provided analytical data indicating that
approximately 98-99% of all wastes treated met the LDR standards
following the first treatment procedure, without the need for
additional treatment. They reported that in 2022, of the 770 put piles
treated and analyzed, 762 met post-treatment LDR standards, resulting
in a net ``pass rate'' of 98.9%. In 2023, 519 put piles were treated
and analyzed and 509 met post-treatment LDR standards (98.1%).
The sampling methodology used by Clean Harbors to verify compliance
with LDR standards for the wastes post-treatment was deemed adequate by
ODEQ through the issuance of the existing RCRA Part B permit, including
the WAP. Clean Harbors' sampling strategy for confirmation of LDR
compliance is discussed in Appendix A of Clean Harbors' September 10,
2024, Response to Request for Additional Information included in the
docket. Clean Harbors reported in the petition that the current ``pass
rate'' for temporarily staged put piles exceeds 98%, demonstrating that
these put piles do not routinely receive treated wastes that do not
meet applicable LDR standards, thereby supporting the ``temporary''
nature of storage for each waste category. The Agency herein relies on
ODEQ's approval of the LDR confirmatory sampling methodology in the WAP
and Clean Harbors' presentation of historical analytical data to
conclude that Clean Harbors has provided sufficient waste
characterization information in its petition to support the conclusion
of treatment effectiveness.
ii. Duration of Temporary Storage
When the LDR standard for a put pile is confirmed to ``pass,'' it
is moved to the working face of Landfill Cell 15 for final disposal
generally within 45 days \7\ of initial placement of the put pile in
the temporary storage area. LDR verification sampling must conform to
the WAP, and a generalized procedure for this verification process is
discussed in Appendix A of Clean Harbors' September 10, 2024, Response
to Request for Additional Information included in the docket.
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\7\ May take up to 90 days in cases when specialized compliance
tests are required or laboratory backup delays LDR compliance
confirmation data.
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The end result of a multi-stage process for sampling and retreating
is that a few put piles may remain temporarily staged even after an LDR
``fail'' if the analytical data indicate additional curing time is
appropriate. Clean Harbors requested up to twelve (12) months duration
for temporary staging of a put pile to account for the retreatment and
curing process; however, in Clean Harbors' August 4, 2025 Response to
EPA's May 2025 Review Comments on the Response to Request for
Additional Information located in the docket, the state agreed that
exceedances of six (6) months of temporary staging have not occurred
and are unlikely and as such agreed that six (6) months are a
sufficient duration for temporary staging of put piles. The Agency
concludes that Clean Harbors has provided sufficient analytical data to
justify a six (6)-month duration for storage of a put pile from the
time the pile is first staged until final disposal in the working face
of the Landfill Cell 15. If an issue arises where greater than 180 days
temporary staging of a put pile is necessary, ODEQ may issue such an
extension, if warranted.
iii. Disposal Unit Engineered Controls
This section describes existing and proposed put pile liners, put
pile covers, and run-off/run-on controls. Man-made barriers or
engineered systems (e.g., liner systems) alone generally will not meet
the ``no migration'' standard. In the case of put piles, however, the
containment of hazardous waste within engineered barriers is considered
in making the ``no migration'' demonstration for waste awaiting the
results of verification sampling after treatment, provided that wastes
are to be removed after a reasonably short storage period that is
conservatively projected to be well before the failure of the
engineered barrier system.\8\ Because Clean Harbors' temporary storage
for each put pile must not exceed six (6) months, and the lifespan of
the engineered barriers described below extends into multiple decades
with appropriate operational controls to prevent rips or tears,
excluding the Posi-Shell[supreg] system, which has an observed lifespan
of up to 2 (two) years, the Agency concurs that Clean Harbors' use of
the barriers described below will prevent migration of hazardous
constituents via infiltration, lateral migration (e.g., erosion,
surface water interaction or movement of infiltration), and air
dispersion/particulate loss.
---------------------------------------------------------------------------
\8\ No Migration Variances to the Hazardous Waste Land Disposal
Prohibitions: A Guidance Manual for Petitioners, at 4, EPA Office of
Solid Waste, July 1992, EPA-530-R92-023.
---------------------------------------------------------------------------
The put piles will be encapsulated (liner below and Posi-
Shell[supreg] atop) by the unit-specific engineered barriers discussed
below to prevent migration of hazardous constituents beyond the put
pile boundary. These unit-specific barriers are distinct from the
existing landfill controls for Landfill Cell 15, such as run-on and
run-off controls, that were considered in the overall prevention of
migration of hazardous constituents.
Liners
A liner of at least 20-mil thickness polyethylene geomembrane must
be used as a barrier to vertical and lateral migration for the put
piles. The liner beneath the pile will provide a barrier for vertical
migration. The Agency agrees that a minimum of 20-mil thickness barrier
is sufficient for this temporary application that will last six (6)
months or less. Because the layout of the put piles is accommodated
within the standard width of a prefabricated geomembrane roll, the
liner must be one solid piece without the need for welding of seams.
The lack of seams lends to additional assurance that hazardous
constituents will not migrate through a broken seam. The Agency
concludes that a liner of at least 20-mil thickness, in conjunction
with the inspection program described in the Compliance Monitoring
Program section, is appropriate for use in this temporary disposal
scenario; however, there must always be at least 12 inches of the liner
visible on all sides of the put pile to prevent potential horizontal
migration of the waste from the edge of the liner.
Covers
Clean Harbors will use a Posi-Shell[supreg] cover to act as a rain
and wind barrier for put piles, to ensure no migration of
[[Page 57441]]
hazardous constituents from the put piles occurs via lateral migration
or air pathways. Posi-Shell[supreg] is a spray-applied mortar applied
as a coating to the surface of the put piles, with a minimum cover
thickness of \3/8\-inch. Because Posi-Shell[supreg] is a mortar, curing
is necessary to allow it to harden. Curing typically occurs within 12-
24 hours in dry weather, forming a relatively impermeable thin layer of
durable, hardened mortar. However, if moderate to heavy rainfall occurs
unexpectedly or is imminent, sustained freezing temperatures are
expected for more than one day, or the temperature falls below 30
[deg]F, the Posi-Shell[supreg] will not harden sufficiently. During
these times of inclement weather, Clean Harbors must temporarily cover
the put piles with polyethylene sheeting of at least 20-mil thickness,
anchored with sandbags around its edges, until the adverse weather
conditions abate, and the Posi-Shell[supreg] coating can be applied.
Within twenty-four (24) hours of weather conditions amenable to Posi-
Shell[supreg] application, Clean Harbors must apply the coating.
To ensure Posi-Shell[supreg] is appropriate for put pile covering,
the Agency reviewed several case studies provided by Clean Harbors
where Posi-Shell[supreg] was demonstrated to prevent erosion, air
dispersion, infiltration of rainwater, and overall migration of wastes.
Table 2 in the petition located in the docket summarizes these case
studies.
The Agency concludes that Posi-Shell[supreg], or a minimum 20-mil
polyethylene sheeting cover under the limited inclement weather
circumstances described above, will serve as an appropriate barrier to
protect the put pile from wind dispersion, erosion, and rainwater
infiltration.
Run-On/Run-Off Controls
Before placing the put piles in the temporary storage area of
Landfill Cell 15, Clean Harbors must grade the temporary storage area
where put piles will be located. The grading must be relatively flat
but with a slight positive grade to preclude ponding of water on the
polyethylene liners. Clean Harbors must construct and/or maintain a
diversion berm of sufficient height/width to direct run-on away from
the put pile upgradient of the staging area. As Landfill Cell 15 is
filled, if the waste grade changes adjacent to the put pile temporary
storage area, additional diversion berms must be added, if necessary to
divert stormwater run-on and run-off to isolate the staging area on the
working face of Landfill Cell 15. To control run-off, in addition to
the Posi-shell[supreg] coating, Clean Harbors will include, at a
minimum, ditches around the inside perimeter of Landfill Cell 15
embankments and will remove ponded stormwater that accumulates on top
of the put piles. In combination with General Surrounding Area
Engineered Controls described below, these controls must be constructed
and operated to contain at least the water volume of a 24-hour, 25-year
storm event or greater if required by the permit.
iv. General Surrounding Area Engineered Controls
All put piles are temporarily stored in a designated area of
Landfill Cell 15 until LDR compliance has been confirmed. The put piles
are then moved to the working face of Landfill Cell 15. Landfill Cell
15's existing liner system bolsters prevention of vertical or
horizontal migration of hazardous constituents. The liner system
consists of: (1) a bottom 60-mil textured high density polyethylene
(HDPE) liner atop a 3-foot-thick compacted clay layer with a hydraulic
conductivity of less than 1.7 x 10<SUP>-7</SUP> cm/sec; (2) a double-
sided geocomposite leak detection system drainage layer; (3) a top
composite liner consisting of geosynthetic clay between two 60-mil
textured HDPE liners; (4) a double-sided geocomposite leak collection
system; and (5) a 2-foot thick cover layer.
v. Groundwater Monitoring
Clean Harbors has a groundwater monitoring well network at the
facility that currently includes five (5) upgradient monitoring wells
and 39 downgradient monitoring wells. In particular, Landfill Cell 15
has five (5) downgradient monitoring wells in its proximity. The wells
are monitored semi-annually under the Groundwater Detection Monitoring
program as required by the facility's RCRA Part B permit for the
analytes set forth therein. The Groundwater Detection Monitoring
program is an attachment to the Part B permit and is located in the
docket. Clean Harbors Lone Mountain has two relevant RCRA permits--an
Operations Permit for current hazardous waste treatment and disposal
activities and a Post-Closure Permit for landfill cell(s) undergoing
closure. In the last 10-year monitoring period, no hazardous waste
constituents have been reported above their respective health-based
levels in groundwater wells that monitor the operating portions of the
landfill where the put piles will be staged. The Permit Renewal
Application is currently undergoing technical review and pending
completion of ongoing Class 3 Tier III Permit Modifications for
container management expansion and proposed Landfill Cell 16.
vi. Sufficient Information
40 CFR 268.6(a)(5) requires that sufficient information exists to
assure the Administrator that the owner/operator of an NMV unit will
comply with other applicable Federal, State, and local laws. Clean
Harbors is in compliance with their state-issued permits, and the
Agency concludes that sufficient assurances exist through the RCRA,
air, and water permits that govern Clean Harbors' treatment, storage,
and disposal operations.
vii. Compliance Monitoring Plan
40 CFR 268.6(a)(4) requires a petition to include a monitoring plan
to verify continued compliance with the conditions of the NMV. The
monitoring plan must be designed to detect migration ``at the earliest
practicable time.'' As stated in the 2023 Guidance, the plan must
include frequent visual monitoring and prompt responses to possible
releases, and generally good housekeeping practices that ensure the
treated waste remains in the pile during the temporary storage period.
The monitoring plan must also include a discussion of the sampling and
analysis of the treated waste that determines when the put pile will be
moved to the working face of the landfill for final disposal.
Clean Harbors must maintain at the facility a put pile monitoring
plan that includes, at a minimum, components 1-16 below, many of which
were included by Clean Harbors in the petition and the Agency adopts as
proposed.
Deficiencies identified during inspection must be remedied/repaired
to ensure no migration of hazardous constituents occurs. Deficiencies
may include but are not limited to cracking, breakdown, or insufficient
application of the Posi-Shell cover; gaps, tears, or holes in plastic
sheeting utilized for the management of the unit; presence of
stormwater run-on flow and/or ponded water; visibly exposed waste; and
poor overall pile condition. Deficiencies must be remedied within one
(1) week of discovery, and remedies must be recorded in the facility's
operating record.
Deficiencies described by this section must be remedied regardless
of whether Clean Harbors determines that a migration of hazardous
constituents has occurred or may have occurred if LDR compliance
verification of the waste in the unit is not yet available. If Clean
Harbors determines that there has been a migration of hazardous
constituents from any of the put piles or is unable
[[Page 57442]]
to remedy any deficiency within one (1) week of discovery, Clean
Harbors must immediately suspend receipt of waste at the affected put
pile and notify the Region 6 Administrator, in writing, within ten (10)
days of the determination that a release has occurred or that a
deficiency was unable to be remedied within one (1) week.
Monitoring Plan Conditions
1. Review and track LDR standard ``pass rates'' for put piles to
ensure that the put piles are only being ``temporarily stored,'' as
described in the February 2023 guidance. If the failure rate of the
initial verification test for treated put piles exceeds 5% in a
calendar month, Clean Harbors must conduct a root cause analysis and
adjust the treatment protocol for the affected category of waste.
2. Inspection of the temporary staging area for put piles must be
performed before installation of the 20-mil polyethylene liner. The
underlying area must be free of large, sharp, or rigid objects that may
damage the liner.
3. Observing that the liner is not displaced or damaged during
placement of the put piles on the liner to confirm the integrity of the
liner beneath a put pile. A damaged liner must be replaced with a new
liner.
4. Daily inspection of covered put piles to verify integrity of the
liner, cover, and overall pile condition. Inspectors must, at a
minimum, check for: (1) signs of stormwater run-on flow that has or is
migrating towards a put pile or other signs of the potential for put
pile erosion, undermining, or washout of the waste encapsulation
barriers; (2) damage from strong winds, heavy rain, or other extreme
weather events (e.g., in particular, causing holes, uplift, or other
breaches in the Posi-Shell[supreg] cover) within 24 hours of such an
event; (3) visible exposed waste; (4) releases of waste (washout/
undermining, displacement/movement of pile, such as shifting or
slumping, windblown waste particles, etc.); (5) other indications of
potential for migration or actual observed migration of hazardous
constituents from the pile (e.g., liquid seeps on the put pile slopes
or emanating from its base); and (6) cracks in the Posi-Shell[supreg].
5. Appropriate Posi-Shell[supreg] application. Adhering to
inclement weather application prohibitions as recommended by the
manufacturer. If a put pile is unable to be immediately covered with a
Posi-Shell[supreg] (e.g., due to moderate to heavy rainfall), the put
pile must be temporarily covered with polyethylene liner that is at
least 20-mil thick and anchored with sandbags around its edges until
the adverse weather conditions abate and the Posi-Shell[supreg] coating
can then be applied. Posi-Shell[supreg] should not be applied when
sustained freezing temperatures are expected for more than one day or
during temperatures below 30 [deg]F.
6. Verify that 100% coverage of Posi-Shell[supreg] is achieved over
the entire put pile (no bare or thin spots).
7. Confirm that the minimum \3/8\-in thickness of Posi-
Shell[supreg] is achieved.
8. Confirm that the Posi-Shell[supreg] cover is sufficiently set
(hardened) before a moderate to heavy rainfall event.
9. Promptly re-apply Posi-Shell[supreg] cover if any deficiencies
are identified during application, including but not limited to lack of
coverage, thickness, or hardening.
10. Check for loss of 100% coverage of Posi-Shell[supreg] or other
signs of cover degradation (imminent potential for loss of barrier
effectiveness or thickness).
Landfill Cell 15-Specific Remediation Requirements
11. Remove ponded water on the landfill surface that could affect
the put piles.
12. Modify, as needed, run-on controls to continue to divert
surface water around the put pile staging area.
13. Maintain or alter, as appropriate, landfill grading to prevent
put pile run-on.
14. Isolate the nine waste categories/groups of put piles from each
other to prevent potential commingling.
15. Maintain landfill equipment.
16. Submit a duplicate copy of the RCRA annual report required by
40 CFR 268.6(c)(3). This will include all LDR verification sampling,
resampling, and retreatment to EPA Region 6 at: Golam Mustafa, Land,
Chemicals and Redevelopment Division, EPA Region 6, 1201 Elm Street,
Dallas, Texas 75270, Mail Code: R6LCR-RP.
V. Conclusion
The Agency proposes that Clean Harbors has successfully
demonstrated, to a reasonable degree of certainty, that there will be
no migration of hazardous constituents beyond the unit boundary for
treated hazardous wastes temporarily stored in put piles within their
permitted Subtitle C hazardous waste Landfill Cell 15 while awaiting
LDR compliance verification.
Therefore, EPA proposes to grant, with the conditions stated
herein, no-migration variances for the nine categories/groups of wastes
designated herein, containing up to 100 put piles at any one time at
Clean Harbors' Lone Mountain facility.
Dated: December 2, 2025.
Walter Mason,
Regional Administrator, Region 6.
[FR Doc. 2025-22553 Filed 12-10-25; 8:45 am]
BILLING CODE 6560-50-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.