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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, 2023 Edition.

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Are Remediation Wastes Hazardous?

Once remediation wastes are generated (i.e., they are solid wastes), a hazardous waste determination for those wastes must be made. Figure 1 is a logic diagram for determining the regulatory status of remediation wastes, and the evaluation steps in this figure are further discussed in the subsections that follow. Basically, this figure walks the reader through the four questions that must be evaluated when making a hazardous waste determination.

Figure 1 Table 1a Table 1b

If remediation waste is a solid waste, the second question to ask [from §262.11(b)] is whether the material is excluded or exempt from the RCRA regulations under §261.4. Few exclusions and exemptions exist for remediation waste. Probably the most useful remediation waste exclusion is for petroleum-contaminated media (soil or ground water) generated during cleanup of petroleum underground storage tanks. [§261.4(b)(10)]

If the remediation waste is not excluded, a determination of whether it meets a listing description or exhibits a characteristic will have to be made.

Are remediation wastes characteristic?

Characteristic determinations for remediation wastes are not particularly difficult. Knowledge can usually be used to determine remediation waste is not ignitable, corrosive, or reactive. An exception is for explosives-contaminated soil/sediment at a DOD facility; if the soil/sediment contains >10 percent explosives, it may propagate a detonation or explode when heated under confinement and so may carry the D003 code.

Here is what EPA has said regarding the use of knowledge to determine if remediation waste is characteristically toxic:

“EPA wants to make clear, however, that a decision that a waste is not characteristic in the absence of testing may not be arbitrary, but must be based on site-specific information and data collected on the constituents and their concentrations during investigations of the site. Based on site data, it will be very clear in some cases that a waste cannot be characteristic; for example, if a waste does not contain a constituent regulated as…toxic, a decision that the waste does not exhibit this characteristic can reliably be made without testing for…toxicity. EPA does not expect to undertake testing when it can otherwise be determined with reasonable certainty whether or not the waste will exhibit a characteristic.” [March 8, 1990; 55 FR 8762]

Based on this language, if the facility has documentation showing certain §261.24 constituents could not be present in a specific remediation waste, the TCLP must be performed only for the other toxicity constituents that cannot be eliminated through knowledge. [EPA/530/R-93/007, RO 11603, 14695] As an alternative to running the TCLP (which is quite expensive), some facilities may ask the lab to run totals analysis for those constituents. Based on the results, the TCLP may then be requested only for those constituents with the potential to exceed regulatory levels.

Are remediation wastes listed?

Hazardous waste listings are based on the source of, or the process that generated, the waste rather than the concentrations of hazardous constituents in the waste. Therefore, analytical testing alone, without information on a waste’s source, will not produce information conclusively indicating whether a given waste meets a listing description. [RO 13181]

In some situations, it is hard for facility owners/operators to determine the source of the waste or contamination, making it difficult to tell if a waste is listed. If the owner/operator has made a good-faith effort to find out if a waste is a listed waste but cannot make such a determination because documentation on the source or process is unavailable or inconclusive, EPA allows the owner/operator to assume the waste is not a listed hazardous waste. (See, for example, December 21, 1988; 53 FR 51444, March 8, 1990; 55 FR 8758, and April 29, 1996; 61 FR 18805.) Consequently, if the waste does not exhibit a characteristic, the RCRA hazardous waste regulations do not apply. This has been EPA’s long-standing policy, which was reaffirmed in RO 14291.

This policy also applies to contaminated soil. According to EPA, the mere presence of contaminants in soil does not automatically make the soil a hazardous waste. The origin of the contaminants must be known in order for the soil to require management as a listed hazardous waste via the contained-in policy. “If the exact origin of the [contaminants] is not known, the soils cannot be considered RCRA hazardous wastes unless they exhibit one or more of the characteristics of hazardous waste….” [RO 12171; see also RO 12392, 14291]

What constitutes a “good-faith effort” to determine the source of the contamination? “The agency believes that by using available site- and waste-specific information such as manifests, vouchers, bills of lading, sales and inventory records, storage records, sampling and analysis reports, accident reports, site investigation reports, spill reports, inspection reports and logs, and enforcement orders and permits, facility owner/operators would typically be able to make these determinations. However…if information is not available or inconclusive, facility owner/operators may generally assume that the material[s] contaminating the media were not hazardous wastes.” [April 29, 1996; 61 FR 18805]

Even though EPA’s guidance summarized above suggests not putting any listed waste codes on remediation waste unless the contaminant source is known, facility personnel need to be very careful about this. We know of enforcement actions where site personnel knew of solvent chemical contamination in soil and ground water but did not assign listed codes during remediation because they could not pinpoint the exact source of contamination (e.g., whether the contamination was caused from spent solvents, new solvents, or nonsolvent chemical use such as freeze protection). Federal enforcement personnel claimed that since certain F-listed solvents were known to have been used extensively at the site for cleaning and degreasing, site personnel should have known some or most of the contamination came from spent solvent usage, necessitating F-codes on remediation wastes. Thus, site environmental personnel should review listed waste determinations for remediation waste with site or corporate legal counsel.

Based on the concerns noted in the previous paragraph, listed codes are sometimes conservatively assigned even though the exact source of contamination is unknown. This consideration is built into the Figure 1 logic diagram for determining the regulatory status of remediation waste. Case Study 1 provides an example of assigning listed codes to remediation wastes contaminated with F-listed solvent chemicals.

Case Study 1

Soil contaminated with pesticides

Soil at industrial facilities undergoing cleanups is occasionally found to be contaminated with pesticides. Questions arise over whether the contaminated soil is a hazardous waste. EPA’s interpretation of this issue for the pesticide chlordane is as follows. According to §261.33(f), chlordane is a listed commercial chemical product that becomes hazardous waste U036 when it is discarded or intended to be discarded in its unused form. Therefore, if it is known unused chlordane was dumped or spilled on the ground, the contaminated soil would be U036 when excavated. However, EPA “did not intend to cover those cases when the chemical is released into the environment as a result of use…. In addition, §261.2(c)(1)(ii) specifically states that commercial chemical products listed in §261.33 are not solid wastes (and, thus, not hazardous wastes) if they are applied to the land and that is their ordinary manner of use.” Therefore, soil contaminated with chlordane as a result of normal application would only be regulated as hazardous waste (if it is excavated) if it exhibits one or more of the characteristics. Chlordane-contaminated soil could exhibit the toxicity characteristic as D020. [RO 11182, 12357, 14921]

This interpretation applies to the application of any product for its intended purpose, which incidentally contaminates soil or other environmental media. For example, it also applies to the practice of spraying buildings with pesticide to kill bugs. Any soil contaminated during this normal pesticide use would not be hazardous unless the soil exhibits a characteristic and is actively managed. A similar example is given in Case Study 2.

Case Study 2

Section 262.70 exempts farmers from the hazardous waste regulations if they dispose of waste pesticides on their own farms (and meet certain other conditions). However, if the soil where the waste pesticides were disposed of is later excavated for offsite disposal, the disposal of the contaminated soil is not covered under the §262.70 exemption. If the soil exhibits a characteristic at the point of generation (excavation), it is subject to the RCRA hazardous waste regulations, including compliance with LDR treatment standards before it is land disposed. [RO 14588]

Remediation wastes contaminated with ICR-only listed wastes

29 wastes were listed solely because they exhibit the characteristic of ignitability, corrosivity, and/or reactivity (i.e., ICR-only listed waste). Even though a facility may have documentation showing certain remediation wastes are contaminated with one or more ICR-only listed waste, the remediation wastes will not be hazardous if, at their POG, they do not exhibit any characteristics.

Evaluating investigation-derived wastes

Investigation-derived wastes (IDW) include drilling muds, cuttings, and purge water from test pit and well installation; purge water, soil, and other materials from collection of samples; residues (e.g., ash, spent carbon, well development purge water) from testing of treatment technologies and pump-and-treat systems; contaminated PPE; and solutions (aqueous or otherwise) used to decontaminate nondisposable protective clothing and equipment. [OSWER Directive 9345.3-03FS]

When determining if IDW exhibits a hazardous waste characteristic, remediation personnel “may rely on knowledge of the properties of the substances from, for example, the safety data sheets (SDSs) prepared by manufacturers, or on the results of tests described in §§261.21–261.24. EPA recommends using knowledge of the properties of materials instead of testing since most…wastes do not exhibit these RCRA characteristics.” [EPA/540/G-91/009, May 1991, available from]

When determining if IDW contains a listed hazardous waste, remediation personnel “should not assume that all IDW contaminated with…hazardous substances are RCRA hazardous wastes, in the absence of positive evidence (e.g., manifests, records, knowledge of generation processes) to support such an assumption…. The waste identification process requires access to manifests, storage records, records of waste sources and their prior use, and other information that is reasonably ascertainable during the [site inspection].” [Emphasis in original.] [EPA/540/G-91/009]

For example, the above-referenced EPA report notes that to determine if IDW contaminated with solvent chemicals is RCRA spent solvent F001–F005 waste, remediation personnel must know if:

  • The solvents were spent and could not be used without reclamation or cleaning;
  • The solvents were used exclusively for their solvent properties; and
  • The solvents were, before use, either 1) pure solvent chemicals listed in the F001–F005 listings, or 2) solvent mixtures and blends that contained a total of 10% or more (by volume) of the solvents listed in F001, F002, F004, and/or F005.

When remediation personnel do not have information on the use of the solvents and their properties before use, the IDW “cannot be classified as containing a listed spent solvent.” [EPA/540/G-91/009] This is CERCLA guidance and should be used with caution when managing IDW at sites not subject to CERCLA.


Topic: Mixed Waste Standards and the LDR Storage Prohibition

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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.