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In the United States, hazardous wastes are subject to regulations mandated by the Resource Conservation and Recovery Act (RCRA). Every month, we provide clear, in-depth guidance on a different aspect of the RCRA regulations. The information presented here is an excerpt from McCoy’s RCRA Unraveled, 2021 Edition.

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RCRA/CERCLA Remediation Interface

In general, RCRA applies to sites that are currently active; that is, a financially viable owner/operator exists, and the site is a hazardous waste generator, is operating under interim status, or has a RCRA permit. When cleanup of these active sites is required, the RCRA corrective action program is implemented if the site is operating under interim status or has a RCRA permit.

The Comprehensive Environmental Response, Compensation and Liability Act (CERCLA—which established the Superfund to help pay for cleanup) typically applies to sites that are not active RCRA sites. The sites may be abandoned (i.e., no owner/operator can be identified) or the owner/operator may be insolvent or unwilling to undertake cleanup actions. Although the Superfund provides funds for cleanup of sites where potentially responsible parties (PRPs) cannot be identified, EPA often seeks to recover funds from PRPs when they can be identified.

When inactive sites are to be cleaned up, activities are undertaken in accordance with CERCLA’s National Contingency Plan (NCP). The NCP is codified at 40 CFR Part 300 and must be complied with if Superfund monies are to be used or if cost recovery for cleanup activities is to be sought from PRPs.

How RCRA sites become subject to CERCLA

Under certain circumstances, sites may become subject to both RCRA and CERCLA cleanup authorities.

Imminent and substantial endangerment

In some cases, an imminent hazard may exist that requires a very prompt response. Both RCRA and CERCLA provide authority for such responses:

  • RCRA Section 7003(a) provides EPA with the authority to issue an administrative order (or file suit) where “any solid waste or hazardous waste may present an imminent and substantial endangerment to health or the environment.”
  • CERCLA Section 106(a) authorizes EPA to act where “there may be an imminent and substantial endangerment to the public health or welfare or the environment because of an actual or threatened release of a hazardous substance from a facility.”

The choice of whether to use RCRA or CERCLA authorities (or both) for immediate responses often depends on the fact that hazardous wastes are a subset of hazardous substances. CERCLA hazardous substances are identified at §302.4 and include many CWA and CAA compounds that are not RCRA hazardous wastes.

If a facility has a release of a hazardous substance, but not a hazardous waste, a response under CERCLA authority would be most appropriate. If a facility has a release of hazardous wastes, a response under RCRA authority would be most appropriate.

RCRA-permitted facilities

Under the NCP, a projected Hazard Ranking Score (HRS) was developed for most RCRA-permitted sites, and any that could potentially become National Priority List (NPL) sites requiring CERCLA cleanup were identified. Although cleanup at a RCRA-permitted site would normally be conducted under RCRA corrective action provisions, EPA has stated that owners/operators who subsequently declare bankruptcy or who are unwilling to undertake corrective action become subject to CERCLA cleanup authority if warranted by the site’s HRS score. [OSWER Directive 9932.1, available at by downloading the document numbered OSWERDIR99321] The policy of making owners/operators of RCRA-permitted facilities subject to CERCLA because they are unwilling or financially unable to undertake corrective action is discussed in the August 9, 1988 Federal Register. [53 FR 30002]

Some RCRA-permitted facilities are already listed on the NPL. EPA’s general policy is to delete RCRA sites that are on the NPL and defer their cleanup to the RCRA corrective action program. Criteria for deleting such RCRA sites from the NPL were issued on March 20, 1995 [60 FR 14641] and November 24, 1997. [62 FR 62523]

As noted in the previous paragraph, EPA’s general policy is for RCRA facilities subject to both CERCLA and RCRA to be cleaned up under RCRA. However, in some cases, it may be more appropriate for the federal CERCLA program or a state/tribal “Superfund-like” cleanup program to take the lead. In these situations, the facility RCRA permit should defer corrective action at the facility to CERCLA or a state/tribal cleanup program. For example, where program priorities differ and a cleanup under CERCLA has already been completed or is underway at a RCRA-permitted facility, corrective action conditions in the RCRA permit could state that the existence of a CERCLA action makes separate RCRA action unnecessary. In this case, there would be no need for the corrective action program to revisit the remedy at some later point in time. [RO 11959]

While deferral from RCRA to CERCLA or vice versa is typically the most efficient and desirable way to address overlapping cleanup requirements, full deferral may not be appropriate at all facilities, and coordination between programs will be required. RO 11959 provides guidance for coordination between programs in these cases. For example, CERCLA or RCRA decision documents should be written so cleanup responsibilities are divided and timing sequences are established.

Some of the most significant RCRA/CERCLA integration issues are associated with coordination of requirements for closure of RCRA-regulated units. Such units are surface impoundments, waste piles, land treatment units, or landfills that receive (or have received) hazardous waste after July 26, 1982. There are a couple of options for tackling this integration issue:

  1. Under a rule issued by EPA on October 22, 1998 [63 FR 56710], EPA or an authorized state can defer cleanup, ground water monitoring, and financial responsibility requirements for a closed or closing RCRA-permitted unit located among SWMUs until such time as those requirements are identified for the surrounding SWMUs during the corrective action process. This type of deferral would usually require modification of the facility’s closure plan for that unit. [63 FR 56724–5]
  2. A cleanup plan for a CERCLA operable unit that physically encompasses a RCRA-regulated unit could be structured to provide for concurrent compliance with CERCLA and the RCRA closure and post-closure requirements. In this example, the RCRA permit could be modified to cite the ongoing CERCLA cleanup and incorporate the CERCLA requirements by reference. [RO 11959]

Federal facilities

Federal facilities are subject to CERCLA due to language in the Superfund Amendments and Reauthorization Act of 1986 (SARA). Similarly, the Federal Facilities Compliance Act of 1992 specified that federal facilities are subject to RCRA. Hence these facilities become subject to whichever RCRA/CERCLA provisions the regulatory agencies decide provide the greatest cleanup authority.

Many federal facilities are very large, and there are often several federal, state, and local regulatory agencies and other interested parties involved in their cleanup. Most federal sites have compliance agreements with the pertinent regulatory agencies; the agreements identify when and where CERCLA and/or RCRA authorities will apply. For example, it is common for the CERCLA process to be used at large federal facilities for cleanup of operable units. Although these facilities typically have RCRA permits, the corrective action requirements for SWMUs and closure plans for RCRA-permitted units are addressed through the CERCLA process.

Numerous federal facilities are listed on the NPL, and EPA recognizes that CERCLA Section 120 imposes special requirements on federal facilities—these requirements must be accommodated in any RCRA/CERCLA coordination approach. One of the methods the agency has developed to implement this coordinated approach is identification of a single lead regulator to oversee the cleanup of federal facility sites on the NPL. This lead-regulator policy is contained in “Lead Regulator Policy for Cleanup Activities at Federal Facilities on the National Priorities List,” November 6, 1997, available at

How CERCLA sites become subject to RCRA

At a site being remediated under CERCLA authority, the cleanup provisions of the NCP require implementation of remedial actions when extensive cleanup activities, such as ground water remediation, are involved. Remedial actions involve a number of distinct steps. First, a remedial investigation (RI) is conducted to characterize the problem and determine the nature and extent of contamination. This is followed by a feasibility study (FS), which evaluates various methods to address site contamination. Formalized screening methods that consider the effectiveness, implementability, and cost of the various alternatives are applied to identify a limited number of options for detailed study.

Using criteria specified in §300.430(e)(9)(iii), the lead agency will identify the preferred remedial alternative for the site and seek public comment. When the decision is finalized, it is documented in the Record of Decision.

Finally, the remedial action undergoes detailed design, construction, and operation. For complex sites, the entire cleanup process may take a number of years, and in some cases decades, to complete.

ARARs drive the cleanup process

CERCLA Section 121 establishes cleanup standards for remedial actions. That statutory section requires involved parties to 1) evaluate standards, requirements, criteria, and limitations under state and federal environmental laws; and 2) ensure that the remedial action results in “a level or standard of control for such hazardous substance or pollutant or contaminant which at least attains such legally applicable or relevant and appropriate standard, requirement, criteria, or limitation.” [Emphasis added.] The CERCLA regulations at §300.400(g) note how lead agencies are to identify these applicable or relevant and appropriate requirements (ARARs). To determine if RCRA regulatory provisions apply during CERCLA cleanups, it is necessary to first see how EPA defines these terms:

Applicable requirements means those cleanup standards, standards of control, and other substantive requirements, criteria, or limitations promulgated under federal environmental or state environmental or facility siting laws that specifically address a hazardous substance, pollutant, contaminant, remedial action, location, or other circumstance found at a CERCLA site. Only those state standards that are identified by a state in a timely manner and that are more stringent than federal requirements may be applicable.” [§300.5] Applicable requirements are legally binding requirements that must either be met or waived.

Relevant and appropriate requirements means those cleanup standards, standards of control, and other substantive requirements, criteria, or limitations promulgated under federal environmental or state environmental or facility siting laws that, while not ‘applicable’ to a hazardous substance, pollutant, contaminant, remedial action, location, or other circumstance at a CERCLA site, address problems or situations sufficiently similar to those encountered at the CERCLA site that their use is well suited to the particular site. Only those state standards that are identified in a timely manner and are more stringent than federal requirements may be relevant and appropriate.” [§300.5] In other words, relevant requirements address a similar situation or problem; appropriate requirements are well suited to a particular site.

Evaluating whether a requirement is “applicable” is a legal and jurisdictional determination. The jurisdictional requirements for RCRA Subtitle C applicability are discussed in Section 2.3 of EPA/540/G-89/006 (available from In general, RCRA Subtitle C requirements for the treatment, storage, or disposal of hazardous waste will be applicable at a CERCLA site if a combination of the following conditions are met:

  • The waste exhibits a characteristic or is listed under RCRA; and
  • Either 1) the waste was treated, stored, or disposed after the effective date of the RCRA requirements under consideration; or 2) the activity at the CERCLA site constitutes treatment, storage, or disposal as defined by RCRA.

Under the second scenario, for example, if the lead agency determines that RCRA characteristic or listed hazardous waste is present at the site (even if the waste was disposed before the effective date of the requirement) and the proposed CERCLA action involves treatment, storage, or disposal as defined under RCRA, then RCRA requirements related to those actions would be applicable.

If a requirement is applicable, all substantive parts must be followed. An applicable requirement is one with which a private party would have to comply by law if the same action was being undertaken apart from CERCLA authority. All jurisdictional prerequisites of the requirement must be met in order for the requirement to be applicable.

A requirement that is “relevant and appropriate” may “miss” on one or more jurisdictional prerequisites for applicability but still make sense, given the circumstances of the site. The determination of relevant and appropriate relies on professional judgment, and is based on environmental and technical factors at the site. There is more flexibility in the relevance and appropriateness determination; a requirement may be “relevant” in that it covers situations similar to that at the site but may not be “appropriate” to apply for various reasons and, therefore, not be well suited to the site. In some situations, only portions of a requirement or regulation may be judged relevant and appropriate. [OSWER Directive 9234.2-01/FS-A, available at]

For example, if a hazardous substance at the site is identical to a RCRA listed hazardous waste, but its source is unknown, RCRA requirements will not be applicable but may be relevant and appropriate if the action taken is regulated by RCRA (e.g., storage). Significant guidance is available in EPA/540/G-89/006 for evaluating whether RCRA requirements are relevant and appropriate in such a scenario.

Once a requirement is deemed relevant and appropriate, it must be attained (or waived) during remedial actions that are carried out onsite. Relevant and appropriate requirements do not have to be met when wastes are sent offsite. If a requirement is not both relevant and appropriate, it is not an ARAR. [EPA/542/R-92/005, available from]

Three types of ARARs must be examined at a specific CERCLA site:

  1. Chemical-specific ARARs—These are usually health- or risk-based numerical values that establish the acceptable amount or concentration of a chemical that may be found in, or discharged to, the ambient environment. For example, the RCRA toxicity characteristic levels codified in §261.24 are a factor of 100 times either SDWA MCL standards or health-based data. Thus, the RCRA ARAR for lead is 0.05 mg/L, which assumes a ground water exposure scenario. Chemical-specific ARARs are given in Exhibit 1-1 of EPA/540/G-89/006.
  2. Location-specific ARARs—These are restrictions placed on the concentration of hazardous substances or the conduct of activities solely because they are in specific locations. Examples of special locations include floodplains, wetlands, historical places, and sensitive ecosystems or habitats. RCRA ARARs that involve location-specific standards are codified at §264.18: 1) new TSD facilities cannot be located within 200 feet of a fault that has had displacement in Holocene time; 2) facilities in 100-year floodplains must be designed to prevent washout in a 100-year flood; and 3) bulk liquid wastes cannot be placed in salt domes, salt beds, or underground mines or caves. Location-specific ARARs for other statutes are given in Exhibit 1-2 of EPA/540/G-89/006.
  3. Action-specific ARARs—These are usually technology- or activity-based requirements selected to accomplish a remedy. Action-specific requirements indicate how a selected alternative must be achieved. RCRA corrective action requirements are the most similar to cleanup activities typically taken at CERCLA sites. Examples of other RCRA requirements that are action-specific ARARs include: capping; closing land disposal units; container storage; constructing new land disposal units; dike and impoundment design, construction, and operation; ground water protection and monitoring; incineration; land treatment; placement of wastes in a land disposal unit (the land disposal restrictions); and tank storage. Action-specific ARARs are given in Exhibit 1-3 of EPA/540/G-89/006.

Detailed procedures that should be used to identify RCRA-based ARARs are given in EPA/540/G-89/006. The procedures must be determined on a site-specific basis, considering the specific chemicals at the site, special features of the site location, and the actions being considered as remedies.

Six statutory waivers from the requirement to attain ARARs are codified at §300.430(f)(l)(ii)(C) and are discussed in some detail in EPA/540/G-89/006.

Substantive vs. administrative requirements

In the definitions for applicable requirements and relevant and appropriate requirements given in the previous section, only “substantive,” as opposed to “administrative,” requirements qualify as ARARs. In EPA/540/G-89/006, EPA defined these two types of requirements as follows:

“Substantive requirements are those requirements that pertain directly to actions or conditions in the environment. Examples of substantive requirements include quantitative health- or risk-based restrictions upon exposure to types of hazardous substances (e.g., MCLs establishing drinking water standards for particular contaminants), technology-based requirements for actions taken upon hazardous substances (e.g., incinerator standards requiring particular destruction and removal efficiency), and restrictions upon activities in certain special locations (e.g., standards prohibiting certain types of facilities in floodplains).”

“Administrative requirements are those mechanisms that facilitate the implementation of the substantive requirements of a statute or regulation. Administrative requirements include the approval of, or consultation with administrative bodies, consultation, issuance of permits, documentation, reporting, recordkeeping, and enforcement. In general, administrative requirements prescribe methods and procedures by which substantive requirements are made effective for purposes of a particular environmental or public health program. For example, the requirement of the Fish and Wildlife Coordination Act to consult with the U.S. Fish and Wildlife Service, Department of the Interior, and the appropriate State agency before controlling or modifying any stream or other water body is administrative.”

Cleanup actions that take place “on-site” must meet the substantive but not the administrative requirements. (“On-site” is defined in §300.5 as “the areal extent of contamination and all suitable areas in very close proximity to the contamination necessary for implementation of the response action.”) Response actions carried out offsite are subject to all applicable provisions, including administrative requirements and any specified procedures for obtaining permits. [EPA/542/R-92/005]

Although administrative requirements are not ARARs at CERCLA sites, the CERCLA program has its own set of administrative procedures that assure proper implementation of cleanup activities.

Based on the above definitions, the following general principles may be used in determining potential RCRA ARARs [March 8, 1990; 55 FR 8756–7, EPA/540/G-89/006, EPA/542/R-92/005]:

  • Substantive requirements usually specify a concentration level or standard of control, and they could also provide performance criteria or location restrictions. For example, performance standards for incinerators and minimum technological requirements for double liners and leachate collection systems for landfills would be substantive requirements.
  • LDR treatment standards would be substantive requirements; detailed guidance on whether LDR standards are ARARs is found in OSWER Directives 9347.3-05FS and 9347.3-07FS, both available at
  • Monitoring requirements are considered substantive for ascertaining whether the levels and limitations set in the decision document have been attained.
  • RCRA permits are not required for CERCLA actions taken entirely onsite.
  • Administrative RCRA requirements, such as reporting and recordkeeping requirements, are not applicable or relevant and appropriate for onsite activities at CERCLA sites.
  • Consultations with administrative bodies are considered administrative requirements.

“To be considered” guidance

ARARs are legally binding laws and regulations. Other information that should be considered for CERCLA remedial actions consists of federal and state environmental and public health criteria, advisories, guidance, and proposed standards. These criteria and guidelines are called “to be considered” (TBC) materials and are meant to complement the use of ARARs—not to compete with or replace them. Because TBC guidelines are not ARARs, their identification and use are not mandatory. However, if no ARARs address a particular situation, TBC documents may be used as a basis for CERCLA actions. Exhibit 1-10 in EPA/540/G-89/006 identifies numerous TBC documents that should be considered, including the following types of RCRA documents:

  • EPA RCRA design guidelines,
  • Permitting guidance manuals,
  • Technical resource documents, and
  • Test methods for evaluating solid wastes, including SW–846.


Topic: Point of Generation for Remediation Wastes

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Considerable care has been exercised in preparing this document; however, McCoy and Associates, Inc. makes no representation, warranty, or guarantee in connection with the publication of this information. McCoy and Associates, Inc. expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal law or regulation with which this information may conflict. McCoy and Associates, Inc. does not undertake any duty to ensure the continued accuracy of this information.

This document addresses issues of a general nature related to the federal RCRA regulations. Persons evaluating specific circumstances dealing with the RCRA regulations should review state and local laws and regulations, which may be more stringent than federal requirements. In addition, the assistance of a qualified professional should be enlisted to address any site-specific circumstances.