6EPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Superfund Publication:
9347.3-09FS
September 1990
A Guide to Delisting
of RCRA Wastes for
Superfund Remedial Responses
Office of Emergency and Remedial Response
Hazardous Site Control Division OS-220
Quick Reference Fact Sheet
On-site CERCLA remedial response actions must comply with the substantive requirements of the Resource Conservation
and Recovery Act (RCRA) when they are determined to be applicable or relevant and appropriate requirements (ARARs). RCRA
requirements are applicable far CERCLA responses involving the treatment, storage, or disposal of RCRA wastes (or when disposal
of the waste being addressed under CERCLA occurred after November 19, 1980). Delisting a RCRA waste (and thus removing
it from regulation under RCRA Subtitle C) is one option available to site managers for addressing wastes or treatment residuals
containing hazardous constituents in low concentrations (i.e., at or near health-based levels). This guide discusses the circumstances
under which deflating wastes may be appropriate and the procedures for delisting a RCRA hazardous waste as part of a
Superfund remedial response. (For additional information, please see Petitions to Delist Hazardous Wastes: A Guidance Manual
(Office of Solid Waste and Emergency Response, April 1985 EPA£30-SW-85-003).)
BACKGROUND
There are two types of RCRA waste that are subject to
RCRA Subtitle C hazardous waste requirements: listed and
characteristic. Listed wastes are regulated under Subtitle C
until they have been delisted, at which time they may be
disposed of in a Subtitle D facility. Delisting requires a
demonstration that a listed RCRA hazardous waste, or a
mixture containing listed hazardous wastes, no longer meets
any of the criteria under which the waste was listed and no
other factors are known that would make the waste
hazardous. Delisting applies only to listed wastes, mixtures
containing listed wastes, or residuals derived from treatment
of a listed waste. Characteristic hazardous wastes do not have
to be delisted in order to be eligible for management in a
Subtitle D facility, but may simply be rendered "non-
characteristic'' (i.e., treated to no longer exhibit any of the
characteristics outlined in 40 CFR Part 261, Subpart C), or
meet the Land Disposal Restriction (LDR) treatment
standards.
For on-site CERCLA remedial response actions, delisting
of RCRA wastes is accomplished by incorporating the
substantive requirements of 40 CFR 260.20 and .22 into the
remedial process. For off-site CERCLA response actions, the
administrative requirements of 40 CFR 260.20 and .22 must
also be met.
WHEN TO CONSIDER DELISTING
Site managers may want to consider delisting when
planning CERCLA response actions that will address
materials contaminated with RCRA listed waste in low
concentrations (including treatment residuals that, despite
treatment, remain listed wastes under the derived-from rule
[40 CFR 2613(c)(2)]). If site managers believe that these
materials pose no significant threat to ground water and that
management in a Subtitle D solid waste disposal facility (to
prevent direct contact) would be fully protective of human
health and the environment, delisting as a potential option
should be evaluated. Unless listed wastes can be delisted,
management of these materials must be in accordance with
Subtitle C (i.e., clean closure or landfill closure with an
impermeable cap, or a hybrid closure where RCRA closure
requirements are relevant and appropriate).
BASIS FOR DELISTING
Under RCRA, once sufficient data are collected on the
waste, and its potential fate and transport, models (see
Highlight 1) are run to evaluate the dilution and attenuation
of constituents at a hypothetical receptor well. The calculated
concentrations of constituents at the hypothetical receptor
well must at least meet the health-based levels used for
delisting decisions for the waste to be successfully delisted.
(Table 1, inserted in this fact sheet, contains the maximum
allowed concentrations (MACs) for specific constituents based
on the current health-based levels (10"* risk) developed by the
Office of Solid Waste for delisting decisions.)
During site characterization and the development of the
baseline risk assessment, if analyses indicate that minimal risks
are posed by identified RCRA listed wastes, (i.e., they are
already at or near delating levels) site managers should
consider management options involving the delisting of wastes.
Delisting evaluations should be made early in the RI/FS
process, thus allowing the requirements and disposal options
associated with delisting to be factored into the detailed
analysis of remedial alternatives. For delistings at CERCLA
sites, OERR recommends that site managers use the same
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Highlight 1 - MODELS USED BY TOE OFFICE OF SOLID WASTE TO JUSTIFY DELISTING PETITIONS
The recently promulgated toxicity characteristic leaching procedure (TCLF) is used to measure the leaching
potential of selected inorganic and organic constituents (55 FR 11798, March 29,1990). For some organics, the Organic
Leachate Model (OLM) (see 51 FR 41084-100, November 13,1986) may be used to estimate the leaching potential of
these constituents. The OLM is based on data from leaching tests performed on wastes with organics. Data generated
from the TCLP (and possibly the OLM) are used in the appropriate models to determine whether the waste will pose a
threat to human health and the environment.
'EPA uses an appropriate model, such as the VHS model, to estimate the ability of an aquifer to dilute the
leacbate toxicants and predict toxicant levels at a receptor well. (See 50 FR 48846, November 27,1985 for a complete
description of the VHS model.) The predicted levels of toxicants from the VHS model are then compared to health-
based levels used in delisting decision-making (e.g., MCLs, RfDs) for those compounds, in an effort to evaluate hazard
potential. •
analytical tests and models as the Office of Solid Waste to
analyze and predict the potential fate and transport of waste
constituents and to substantiate a delisting request.
In certain cases, pathways other than ground water may
present a greater concern, or site conditions are such that use
of other or additional models (e.g., air models, 51 FR 41084,
November 13, 1986) may be appropriate. Because the
delisting determination is waste-specific, site managers should
document why a particular model is being used.
If results from treatability studies conducted during an
RI/FS indicate that treatment will attain delisting levels, these
data may serve as the basis for approving a delisting
demonstration. When site-specific treatability study data are
not available, data from the application of technologies to
similar wastes may be used to assess the likely effectiveness of
the treatment processes and to demonstrate that a particular
waste would be rendered non-hazardous and justify a
delisting. If there are technically sound reasons to believe
that delisting levels can be attained, site managers still may
seek to delist the wastes, but should specify another option
for disposal of the material (i.e., Subtitle C disposal) if
delistable levels are not attained.
As outlined in the NCP (55 FR 8756, March 8, 1990),
only the substantive requirements of delisting must be met for
on-site CERCLA responses. The delisting may be granted
when the Regional Administrator signs the ROD. For off-site
actions, the Office of Solid Waste and Emergency Response
(Contact: Assistance Branch (OS-343) 382-4206) makes
delisting decisions. The formal RCRA administrative process
for delisting would not apply, however, to non-contiguous
CERCLA facilities meeting the criteria to be treated as one
site and to which the on-site permit exemption extends (see
NCP, 55 FR 8690-1, March 8, 1990).
DEMONSTRATING COMPLIANCE
Verification testing may be required following treatment
of the wastes to confirm that delisting levels are attained.
Verification testing may require: collection of samples
generated from treatment systems; analysis of samples for
total and TCLP leachate concentrations of inorganic and
organic constituents, and any other RCRA characteristics (as
appropriate)1; and analysis of any other information relevant
to the delisting that may not have been anticipated at the
time that the original decision document was signed. The
specific demonstrations required may vary based on process-
or waste-specific conditions at the site. [NOTE: An
appropriate testing frequency of treatment residuals will need
to be established during the design phase for a period long
enough to represent the variability of the delisted material.]
All data from verification testing must be collected using the
appropriate QA/QC procedures (such as those contained in
the site's Quality Assurance Project Plan (QAPP) prepared
during the RI/FS scoping or remedial design process).
Waste to be delisted must be managed as hazardous until
it has been analyzed in accordance with the sampling and
analysis requirements established at the time of delisting, and
it has been determined that delisting levels have been
attained. Therefore, temporary storage of waste residuals will
be necessary in some cases until sampling results are received.
RCRA storage requirements that are ARAR must be met
(or a waiver justified) during this period for remedial actions.
DOCUMENTING A WASTE DELISTING
Although compliance with the RCRA administrative
delisting requirements are not required as part of an on-site
CERCLA remedial response, compliance with the substantive
requirements of delisting must be documented in the
appropriate CERCLA documents. Since off-site CERCLA
responses must comply with both substantive and
administrative requirements, site managers must follow the
formal delisting petition process (40 CFR 260.20 and .22)
when hazardous wastes or waste residuals are to be delisted
for management off-site. This includes Office of Solid Waste
review, or State review for those States that have adopted the
delisting program at least equivalent to the Federal program,
publication of a proposed notice in the Federal Register, an
opportunity for public comment, and publication of the final
rule in the Federal Register. The Office of Solid Waste's goal
*Note that for any responses expected to take place prior to the
TCLP effective date, the EP Toxicity test may apply.
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Is to propose and finalize delistings within 24 months from the
time a complete petition is received.
RI/FS Report
The substantive requirements for delisting a RCRA
hazardous waste should be documented in the RI/FS Report.
In the Detailed Analysis of Alternatives chapter of the FS
Report, a general discussion of why delisting is warranted
should be included in the description of each alternative for
which a delisting is contemplated. Where the remedial
alternatives involving treatment are expected to result in a
residual that may be delisted, this discussion should also
specify the concentrations of each waste constituent expected
to remain after treatment. The specific information that
should be included in an RI/FS report for on-site and off-site
CERCIA remedial actions is presented in Highlight 2. (The
more specific and detailed information, such as relevant waste
analysis data from sampling, should be placed in an appendix
to the report.) Under the "Compliance with ARARs"
Criterion, as part of the Description of Alternatives section,
site managers should identify those wastes or waste residuals
to be delisted, and managed under Subtitle D instead of
Subtitle C.
Proposed Plan
The intent to delist wastes should be stated in the
Description of Alternatives section of the Proposed Plan.
Because the Proposed Plan solicits public comment on all of
the remedial alternatives, and not just the preferred option,
the intent to delist wastes on-site or to obtain a delisting
petition for off-site wastes should be identified for all
alternatives for which such an approach is planned. This
opportunity for public comment on the Proposed Plan fulfills
the requirements for public notice and comment on delisting
petitions required under 40 CFR 260.20(d). Highlight 3
provides sample language for the Proposed Plan.
Record of Decision
Sample language for the Description of Alternatives
section of the ROD is shown in Highlight 4. The
documentation provided in the ROD should be a brief
synopsis of the information in the FS report. In the
Description of Alternatives section, as part of the discussion
of major ARARs for each remedial alternative, site managers
should include a statement (as was done in the FS report)
that explains why delisting is justified. A statement should
Highlight 2 - DOCUMENTATION FOR RI/FS REPORT FOR DELISTING
(Detailed Analysis of Alternatives Chapter)
ON-SITE:
• Description of Remedial Alternatives
• Detailed Description of the Treatment Process being used to render the waste non-hazardous (e.g., operating parameters)
• Waste and Treatment Residual Characterization
- EPA Hazardous Waste Number(s)
- Complete Description of the Waste (e.g., matrix, percent solids, pH)
- Waste Management Information (e.g., current and proposed management, techniques, flow diagrams)
- Description of Constituents present (identification, concentrations)
• Relevant Sampling and Testing Information1 (e.g., TCLP test results)
• Data on Representative Samples for the Listed Constituents and a Discussion of Why the Waste is Non-Hazardous. Include
a statement that the samples are representative of constituent concentrations in the waste, and discuss modelling results.
• CERCLA on-site response actions need not meet administrative procedures of other environmental statutes. The RI/FS and
ROD process are substitutes for the administrative procedures in the delisting process. The substantive requirements remain
the same (55 FR 8756 -57, March 8,1990).
OFF-SITE (In addition to elements required for off-site petition):
For off-site delisting petitions, the documentation requirements listed for on-site actions should be extracted from the RI/FS
report and combined with the following information found below. The information should be incorporated with the on-site information
into a 40 CFR 260.20 petition and a copy of the petition should be referenced and attached to the RI/FS report.
- Petitioner's name and address
Identification of on-site contact person, if different from above
- Description and location of site
- Statement of the petitioner's interest in the proposed action
1 Appropriate sampling information may be contained in the Superfund Quality Assurance Project Plan (QAPP) and, therefore, not
specifically repeated in the RI/FS Report. Where appropriate, however, information on relevant sampling procedures should be
referenced in this section when discussing the basis for delisting.
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Highlight 3: SAMPLE LANGUAGE
FOR THE PROPOSED PLAN
Description of Alternatives section:
Under this alternative, the [waste/treatment
residuals] wUl be delisted (ie., shown to be non-
hazardous wastes) and thus will no longer be subject to
RCRA Subtitle C hazardous waste regulations. The
[wastes/treatment residuals J will be managed in
accordance with the RCRA Subtitle D (solid waste)
requirements (and/or state solid waste disposal
requirements).,^ , » ^ ,
*<•',. I 1-
Evaluation, of&tterriatives *!
With.ARARs";
under "Compliance
The [wastes/treatment residuals} will be
delisted in [Enter number] of [Enter total number of
alternatives]. The RCRA Subtitle D (solid waste)
closure requirements, rather than Subtitle C
requirements, will be ARARs for these [wastes/treatment
residuals].'
Community's Role in Selection Process:
The Proposed Plan seeks comment on the
delisting of the [waste/treatment residuals and models]
for each alternative for which delisting is proposed.
also be included explaining that the waste was delisted under
CERCLA, therefore RCRA's substantive requirements have
been met.
In the Statutory Determinations section, under the
"Compliance with ARARs" rinding, site managers should
indicate that the wastes will be delisted.
Unless treatability studies conducted in the RI/FS indicate
that a technology's performance is reasonably certain, the
ROD should address how to handle wastes that do not
achieve delistable levels. If waste residuals cannot be delisted,
a contingency plan will be implemented. Where the
contingency implemented differs significantly from that
Highlight* SAMPLE LANGUAGE
FOR THE RECORD OF DECISION
Description of Alternatives section:
Because existing and available data and the
results of modeling demonstrate that the [waste/treatment
residuals] win not be hazardous (ie., do not contain
hazardous constituents in levels that are hazardous and
do not exhibit a hazardous characteristic), they win be
delisted. Therefore, the RCRA Subtitle C requirements
are not ARARs. These {wastes/treatment residuals],
however, will be managed as solid wastes under RCRA
Subtitle D [and State of {name} solid waste disposal
requirements under {citation}]. This delisting is justified
on the basis of [results from treatability testing/other
basis]. This delisting satisfies the substantive
requirements of 40 CFR 260.20 and .22,
If testing of the waste during the remedial
action shows that the necessary levels are not being
attained for delisting these wastes, they will be managed
as Subtitle C hazardous wastes and the applicable or
relevant and appropriate requirements under Subtitle C
will be met.
discussed in the ROD, the ROD must be amended or an
Explanation of Significant Differences (BSD) issued (NCP
§300.435(c)(2)). Where, the contingency implemented does
not significantly differ from that discussed in the ROD, it may
be advisable to issue an BSD or fact sheet to inform the
public of these actions.
The Comparative Analysis section of the ROD should
discuss contingent remedies in a level of detail that is
adequate to explain the contingency (so that the public has an
ample opportunity to review the contingency). The Selected
Remedy section should establish the parameters of both the
selected and contingent remedies and provide the criteria by
which the contingency remedy would be implemented. The
Statutory Determinations section should demonstrate how
either remedy would fulfill CERCLA section 121
requirements.
NOTICE: The policies set out in this memorandum are intended solely as guidance. They are not intended, nor can they
be relied upon, to create any rights enforceable by any party in litigation with the United States. EPA officials may decide to
follow the guidance provided in this memorandum, or to act at variance with the guidance, based on an analysis of specific
site circumstances. The Agency also reserves the right to change this guidance any time without public notice.
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