Previous Corner.


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, 2019 Edition.

Learn more >   Buy >   Compliance Corner >

©2019 McCoy and Associates, Inc. All rights reserved.

Corrective Action

The corrective action program is an important part of RCRA, but the federal regulations contain few specific corrective action requirements. Prior to enactment of the Hazardous and Solid Waste Amendments of 1984 (HSWA), EPA established a program (in Part 264, Subpart F) for monitoring and remediating releases to ground water from permitted hazardous waste surface impoundments, waste piles, land treatment units, and landfills. These regulations were codified in 1982 and are not the subject of this article.

In 1985, EPA added §264.101 to Subpart F. This section basically reiterates the language in RCRA Section 3004(u); that is, it requires corrective action for releases from solid waste management units (SWMUs) at facilities seeking a RCRA permit. This article summarizes the origins of the corrective action program and discusses how we got to where we are today. It also defines the primary terms (e.g., solid waste management unit) and triggers that determine the scope and applicability of this program. A future article will review the steps required to implement a full corrective action at a TSD facility and discuss strategies EPA uses to measure corrective action progress and completion, both at an individual facility and nationwide.

Regulatory Background

In 1987, EPA amended §264.101 to implement RCRA Section 3004(v); that is, the regs were revised to indicate that a facility owner/operator must implement corrective action beyond its facility boundary, where necessary, unless it cannot get permission from the neighboring property owner. At the same time, EPA amended the Part B permit application requirements, adding a provision that requires permit applicants to submit information on the SWMUs at their facility. [§270.14(d)]

EPA proposed a major rule on July 27, 1990 [55 FR 30798] that would have codified detailed procedures and technical requirements (in a new Part 264, Subpart S) for implementing corrective action under Section 3004(u). The 1990 proposal was very controversial, however, and most of it was never finalized. Even so, soon after it was published, EPA and states authorized to administer the corrective action program began using the proposed rule and associated preamble as the primary guidance for the corrective action program. One part of the 1990 Part 264, Subpart S proposal was finalized in 1993; it deals with corrective action management units (CAMUs) and will be discussed in a future Compliance Corner.

On May 1, 1996 [61 FR 19432], EPA published an advance notice of proposed rulemaking (ANPRM) outlining its strategy for codifying corrective action regulations. The ANPRM summarized the agency’s experience with corrective action up to that point, identified several problems with the way the program was being implemented, and requested comment on a number of issues. EPA now considers the 1996 ANPRM the primary guidance for implementing corrective action. [RO 14021]

The agency announced its decision to withdraw most provisions of the 1990 Subpart S proposal on October 7, 1999. [64 FR 54604] The regulations in Subpart S that had already been finalized (i.e., the CAMU regulations) were not withdrawn. At the same time, the agency indicated that it has no plans to issue additional corrective action regulations. As a result, the statutory corrective action requirements of Section 3004(u) continue to be implemented based on policy documents and guidance, such guidance primarily being the 1990 Subpart S proposal and the 1996 ANPRM. These two documents are the basis for much of this article. We turn now to EPA’s definitions of the terms Congress used in RCRA Section 3004(u), as enacted by HSWA.

Solid waste management units

Facilities subject to corrective action are required to investigate and possibly clean up releases of hazardous wastes or constituents from “solid waste management units.” According to EPA, a SWMU is “any discernible unit at which solid wastes have been placed at any time, irrespective of whether the unit was intended for the management of solid or hazardous waste. Such units include any area at a facility at which solid wastes have been routinely and systematically released.” [55 FR 30808]

A discernable unit in this context includes all of the types of units typically used for waste management, such as landfills, surface impoundments, land treatment units, waste piles, tanks, sumps, container storage areas, incinerators, and injection wells. Note that wastewater treatment units and waste recycling units are generally exempt from the hazardous waste management requirements of RCRA but are considered SWMUs subject to corrective action. [55 FR 30808] Industrial sewers that collect wastes from manufacturing processes are SWMUs, as are open ditches that convey wastewater.

Old, inactive waste disposal areas, such as old disposal trenches, pits, and open burn areas, would qualify as SWMUs, regardless of when the disposal occurred. Maintenance areas have also been identified as SWMUs at permitted facilities. Additional units/areas that have been identified as SWMUs are listed in Table 1.

Table 1

Should a scrap metal storage area be considered a SWMU?

Even though scrap metal destined for recycling is not regulated as a hazardous waste under RCRA, it is considered a solid waste [see Table 1 in §261.2(c)]. Therefore, a scrap metal storage area could be a SWMU. [RO 12415]

If a storm water retention pond contains sediments that fail the TCLP, would it be considered a SWMU?

The term “SWMU” includes any unit at a facility from which hazardous constituents might migrate, irrespective of whether the unit was intended for the management of solid or hazardous waste. Therefore, storm water retention ponds containing sediments that fail the TCLP would generally be considered SWMUs. [RO 14253]

Military firing ranges and impact areas are often hazardous due to the presence of unexploded ordnance. Are these areas solid waste management units?

No. These areas should not be considered SWMUs. Unexploded ordnance and fragments of exploded ordnance fired during target practice are not discarded materials—they are materials being used for their intended purpose. Hence, these materials are not solid wastes. [55 FR 30809]

Routine and systematic releases

The definition of SWMU includes “any area at a facility at which solid wastes have been routinely and systematically released.” One example of such a SWMU would be a “kickback drippage” area at a wood preserving facility, where pressure-treated wood is stored in a manner that allows preservative fluids to routinely and systematically drip on the soil. Another example might be an area at a facility where rail cars are loaded and unloaded. If a hose used to load/unload the cars was disconnected and dropped on the ground repeatedly, releasing a small amount of material that, over time, resulted in contaminated soil, this area would be considered a SWMU. Still another example would be an outdoor area at a facility used for solvent washing of large parts. If the solvents were allowed to continually drain on the soil, that area could be considered a SWMU.

At one point in time, EPA issued guidance indicating that routine, systematic, and deliberate releases are subject to corrective action. The agency later decided that areas which have become contaminated by routine and systematic releases of hazardous wastes or constituents are SWMUs. “It is not necessary to establish that such releases were deliberate in nature.” [RO 12969]

The “routine and systematic” language is important to remember during the SWMU identification process. Facilities have been able to use this language to their advantage in removing potential SWMUs from the state’s preliminary list.

Are one-time spills or leakage from product storage or production processes subject to corrective action?

“A one-time spill of hazardous wastes (such as from a vehicle traveling across the facility) would not be considered a solid waste management unit. If the spill were not cleaned up, however, such a spill would be illegal disposal, and therefore subject to enforcement action under Section 3008(a) or Section 7003 of RCRA. Similarly, leakage from a chemical product storage tank would generally not constitute a solid waste management unit; such ‘passive’ leakage would not constitute a routine and systematic release since it is not the result of a systematic human activity. Likewise, releases from production processes, and contamination resulting from such releases, will generally not be considered solid waste management units, unless [EPA or the state] finds that the releases have been routine and systematic in nature. (Such releases could, however, be addressed as illegal disposal….)” [55 FR 30809]

Manufacturing and product storage areas

The last question and answer raises another question: “Can manufacturing process units or product storage tanks be considered SWMUs subject to corrective action?” EPA has given conflicting answers to this question.

In a 1988 guidance document, the agency indicated product or process units would not be SWMUs. But, areas contaminated by routine and systematic discharges from product or process units would be SWMUs. [RO 13125] In 1991, EPA again held the position that a product tank would not be considered a SWMU because it was used exclusively to store product. However, the agency did not render a definitive opinion as to whether the area surrounding and underneath the leaking tank should be considered a SWMU, choosing to rely instead on other authorities [i.e., the “omnibus” provisions in §270.32(b)(2)] to address the releases at the site. [RO 13441]

In 1998, EPA took a more aggressive posture as to whether manufacturing process units could be considered solid waste management units. The agency noted in RO 14309 that manufacturing process units often hold materials that can be classified as solid wastes and potentially hazardous wastes (e.g., precipitated residues). Even though these materials are exempt from hazardous waste regulation under §261.4(c), they are still considered solid wastes, thereby rendering the manufacturing process units as solid waste management units. However, EPA may exercise differing statutory authority to require cleanup at the facility.

We have two things to say about this issue: 1) It would be helpful if EPA issued additional guidance to clarify whether the 1998 interpretation reflects the agency’s current stance on manufacturing process units as SWMUs; and 2) such manufacturing units are potentially subject to the corrective action program as SWMUs, but only RCRA-permitted and interim status facilities are subject to corrective action.

EPA discourages arguing about “SWMUs”

The definition of “SWMU” is often a point of disagreement when corrective action permits or orders are issued. Facility owners/operators often argue that the RCRA corrective action program should be focused on waste management units and that nonwaste management related releases (e.g., spills of raw materials or products) should be addressed by other cleanup programs. On the other hand, EPA believes that corrective action can be used to address all unacceptable risks to human health or the environment at RCRA-permitted facilities. Citing their authority to require cleanup of non-SWMU related releases under other statutory authorities, EPA asserted that “extended debate or litigation over a particular SWMU designation will in many cases be unproductive for all parties and, as a general principle, EPA discourages debate on these issues….” [May 1, 1996; 61 FR 19443]

Areas of concern

When EPA or a state issues a corrective action permit or order, they sometimes require facilities to investigate releases in an “area of concern.” This term has no specific definition; it is basically a catch-all term used to require facilities to investigate potential releases, regardless of whether they are associated with a specific SWMU. For example, when an overseeing agency believes one-time spills of hazardous wastes or constituents have not been adequately cleaned up, these releases are often addressed as areas of concern. Depending on the extent of contamination associated with such releases, the area may subsequently be designated a SWMU.

Hazardous waste and constituents

Under the corrective action program, RCRA Section 3004(u) requires facilities to be concerned with releases of “hazardous waste or constituents” from SWMUs. The hazardous constituents do not necessarily have to be derived from hazardous waste; they may be derived from nonhazardous wastes. In 1990 [55 FR 30874], EPA proposed the following definitions for these terms:

Hazardous constituent means any constituent identified in Appendix VIII of 40 CFR Part 261, or any constituent identified in Appendix IX of 40 CFR Part 264.”

Hazardous waste means a solid waste, or combination of solid wastes, which because of its quantity, concentration, or physical, chemical, or infectious characteristics may cause, or significantly contribute to, an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness; or pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, or disposed of, or otherwise managed. The term hazardous waste includes hazardous constituent as defined above.”

A few notes on these definitions are in order.

  1. The proposed definitions were never finalized but are the only guidance for these terms available.
  2. The definition of “hazardous constituent” given above references Appendix VIII of Part 261 and Appendix IX of Part 264. Appendix IX is basically a subset of Appendix VIII; that is, it consists of those Appendix VIII constituents for which it is feasible to analyze in ground water samples. However, Appendix IX also includes constituents not found in Appendix VIII that are commonly addressed at Superfund ground water cleanups.
  3. The definition of “hazardous waste” given above is the same as the statutory definition found in Section 1004(5) of the RCRA statute but is broader than the regulatory definition in §261.3.

Finally, EPA indicated that investigation of releases from SWMUs should focus on the hazardous wastes and constituents likely to have been released at a particular site, based on the available information. “Only where very little is known of waste characteristics, and where there is a potential for a wide spectrum of wastes to have been released, would the owner/operator be required to perform extensive or routine analysis for a broader spectrum of wastes.” [55 FR 30809–10]


A “release,” as included in RCRA Section 3004(u), is any “spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the…air, surface water, ground water, and soils….” [July 15, 1985; 50 FR 28713] This is essentially the same as the CERCLA definition of release. EPA also considers abandoned or discarded containers that have hazardous waste or constituents inside a “release.” [55 FR 30808] In some situations, EPA will impose RCRA corrective action requirements on releases that were permitted under some other environmental program, such as the Clean Water Act.


For purposes of Section 3004(u) corrective action, a “facility” is all contiguous property under the control of the owner or operator seeking a RCRA permit. [§260.10] Two parcels of land under common ownership but separated by a road or public highway are considered to be contiguous and constitute a single facility. The term “contiguous property” is also significant when applied to a facility that is owned by one entity and operated by another. In 1990, EPA gave the following example: If a 100-acre parcel of land is owned by a company that leases five acres of it to another company, and the second company stores hazardous waste on the five leased acres, the facility for purposes of corrective action would be the entire 100-acre parcel. [55 FR 30808] In 1996, the agency reconsidered this approach, noting that there are differing views regarding the policy merits of the foregoing interpretation and inviting further public comment. [61 FR 19442]

Another situation in which the definition of “facility” is important is when two adjacent properties are owned by subsidiaries of the same corporate parent. For example, in some parts of the country it is common for a petroleum refinery and a chemical plant to be co-located (i.e., they share a common boundary), as shown in Figure 1. The refinery is owned by XYZ Refining Company, and the chemical plant is owned by XYZ Chemical Company. The chemical plant is seeking a RCRA permit for a hazardous waste management unit. Ordinarily, these would be considered two separate facilities; for example, they have two separate EPA ID numbers. However, because both companies are subsidiaries of the same parent, XYZ Corporation, then, even though only the chemical plant is seeking a RCRA permit, both properties constitute one facility for purposes of corrective action. [55 FR 30808]

Figure 1

Another common scenario involves two geographically separated parcels of land owned by the same person. If the properties are connected by ditches, bridges, sewer systems, or other links under the control of the facility owner/operator, they can be considered a single facility. In one case, evaporation ponds three miles from a refinery were considered part of the facility, because they were linked to the refinery by a drainage ditch controlled (although not owned) by the refinery owner. [61 FR 19442]


Topic: CAMUs, Temporary Units, and Staging Piles

©2019 McCoy and Associates, Inc. All rights reserved.

McCoy and Associates has provided in-depth information to assist environmental professionals with complex compliance issues since 1982. Our seminars and publications are widely trusted by environmental professionals for their consistent quality, clarity, and comprehensiveness.



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.