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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, 2019 Edition.

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

Introduction to Listed Wastes

Generators of a solid waste determine if it exhibits a characteristic primarily by testing or otherwise evaluating the properties of the waste. Conversely, generators determine if they have listed wastes principally based on knowledge of the source of the waste. A listed waste is hazardous not because of the concentration of any contained constituents, but because it meets a listing description on one of the four lists of hazardous wastes in the regulations. The primary criterion for applying a listed code to a waste is that you know the source of the waste (i.e., the process that generated the waste).

Appendix VII of Part 261 identifies the hazardous constituents typically contained within each listed waste that EPA was worried about when it listed the waste (i.e., these constituents form the basis for the listing). However, if a solid waste meets a listing description, it is that listed hazardous waste—regardless of its actual composition and constituent concentrations—even if the manufacturing and/or treatment processes do not use any of the constituents for which the waste was listed (unless the generator gets a delisting petition approved). [September 25, 2015; 80 FR 57939, RO 13586, 14103, 14482, 14691, 14699]

EPA has recently started to take a new approach with regard to listed wastes: conditional listings. Under this approach, a waste is not listed on the condition that it will be managed in a particular manner that EPA considers to be protective of the environment. For example, K174 wastewater treatment sludges are not listed hazardous wastes if they are managed in Subtitle C landfills or nonhazardous waste landfills permitted by the state or federal government, and provided the sludges are not placed on the land prior to final disposal.

This article contains a brief description of the four lists of hazardous wastes and where they can be found in the regulations.

Four lists of hazardous wastes

The F-wastes are found in §261.31—Hazardous wastes from nonspecific sources. Twenty-eight F-wastes are currently identified having waste codes ranging from F001 through F039 (obviously, some gaps exist in the numbering system). The concept behind this set of listed wastes is that they are manufacturing process wastes produced by a wide variety of industrial operations; that is, they are process wastes generated from nonspecific sources. The 28 different wastes can be grouped as follows:

  • F001–F005—These are the spent solvent listed wastes; they are generated if a facility uses one of the solvents in the F001–F005 waste listings.
  • F006–F019—Specific wastes from electroplating or heat treating operations carry these listed codes. EPA is primarily worried about their heavy metal and cyanide content.
  • F020–F023 and F026–F028—These wastes all contain dioxins or dioxin precursors. Although EPA considers them to be acutely hazardous, hardly anyone manages significant quantities of these wastes.
  • F024 and F025—Process wastes from the production of chlorinated aliphatic hydrocarbons by free-radical catalyzed processes are assigned these listed waste codes. Here’s where EPA’s system of assigning F-codes to wastes from nonspecific sources starts to break down; these wastes are not generated outside of the organic chemical industry.
  • F032, F034, and F035—These three wastes are all associated with the wood preserving industry. Here again, these three wastes don’t seem to belong on the F-list because they are only generated by one industry.
  • F037 and F038—Primary and secondary sludges produced primarily in wastewater treatment systems at petroleum refineries are F037 or F038. These waste codes were developed to capture wastes not otherwise covered by the K048–K052 listings.
  • F039—This waste code is for multisource leachate produced at facilities (typically landfills) conducting land disposal of more than one type of listed hazardous waste.

Manufacturing process wastes from specific industries/sources make up the K-list in §261.32. This list is subdivided into groups of wastes generated from several specific industrial categories: inorganic pigments, organic chemicals, pesticides, etc. In order to use the K-list, a generator first determines if his/her operations fit within any of the industrial categories (e.g., wood preservation or inorganic pigment manufacturing). Once the industrial category is identified, the generator checks to see if his/her wastes meet any of the K-waste listing descriptions in that category. The generator should not be concerned about the K-wastes associated with the other industrial categories. For example, if a generator is in the petroleum refining industry, the nine K-wastes included under that industrial category may be applicable; the K-wastes in all the other industry categories will not be applicable. Obviously, if a facility fits into several industrial categories (e.g., it is a petroleum refinery and an organic chemical manufacturing facility), the K-wastes in each industrial category could be applicable.

The listing descriptions associated with the K-wastes are generally very specific and clear. When questions are put to EPA as to the applicability of a particular K-waste code, the agency notes in general that “[o]ur interpretations on the applicability of RCRA [K-] codes are based on the consideration of 1) the descriptive regulatory language, 2) the regulatory intent of the original listing, and 3) facts specific to the waste stream at issue.” [RO 13679]

When people aren’t sure if a particular K-waste listing applies to their waste, we usually suggest that they obtain and read EPA’s listing background document prepared for every F- and K-waste. These documents are quite specific about the particular waste streams the agency wanted to capture via the listings. Listing background documents can be obtained from by entering RCRA-2004-0016 for F-listed wastes or RCRA-2004-0017 for K-listed wastes in the search field. Alternatively, you may request this information by emailing or phoning the EPA Docket Center at (202) 566-0270.

The last two lists of hazardous wastes, the P- and U-lists, are both found in §261.33. These two lists identify unused commercial chemical products that, when discarded, pose a threat to human health or the environment, usually due to their toxicity.

EPA has developed an excellent guidance document for listed hazardous wastes: Hazardous Waste Listings—A User-Friendly Reference Document, September 2012, available at The document contains hyperlinks, so its usefulness is maximized when viewed on a device that is online. It includes hyperlinks to Federal Register notices, letters and memoranda issued by EPA, and other relevant documents that provide clarification of the hazardous waste listings.

ICR-only listed wastes

There are 29 listed wastes that were listed solely because they exhibit the characteristic of ignitability, corrosivity, and/or reactivity (what we call ICR-only listed wastes—see Table 1). At the federal level, these 29 F-, K-, P-, and U-wastes are not hazardous if, at the point of generation, they do not exhibit any characteristics. [§261.3(g)(1), May 16, 2001; 66 FR 27266, RO 14638, 14654] EPA clarified this requirement as follows: “if a listed hazardous waste is listed solely because it exhibits the characteristics of ignitability, corrosivity, and/or reactivity, and the waste does not exhibit the characteristic for which it was listed, then it is not a hazardous waste....” [December 2, 2008; 73 FR 73524; see also EPA/530/F-11/003] Because this rule, issued in May 2001, is less stringent than the pre-existing regulations, states were not required to adopt it. To see if your state has adopted this rule, download this document: Authorization Status of all RCRA/HSWA Rules, at, and scroll down to page 282.

Table 1

A generator in a state that has adopted the May 2001 ICR-only listed waste rule manages spent acetone solvent that does not exhibit a characteristic as nonhazardous waste. What happens if the generator ships the waste to a TSD facility located in a state that has not adopted the rule?

While traveling through any state that has not adopted the May 2001 rule, the spent acetone solvent meets the F003 listing description and must be managed as hazardous waste. Thus, a hazardous waste transporter and manifest must be used, and all other Part 263 requirements must be met. At the TSD facility, the waste must be managed as any other F003 hazardous waste. [RO 14716]

State-listed wastes

Because the RCRA statute allows states to have broader, more-stringent regulations than the federal program, some states regulate what we call “state-listed wastes.” These are wastes that are not included on any of EPA’s F-, K-, P-, or U-lists, but they are considered listed hazardous wastes within that state’s boundary. For example, some states have added PCBs as listed waste, and there would be a special code for this state-listed waste. A couple of states have listed waste codes for chemical warfare agents that are being destroyed at facilities within these states.


Topic: Solvent-Contaminated Rags/Wipes

©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.