Defining Hazardous Waste: Listed, Characteristic and Mixed Radiological Wastes
Click on a step in the hazardous waste identification process for more information.A solid waste is a hazardous waste if it is specifically listed as a known hazardous waste or meets the characteristics of a hazardous waste. Listed wastes are wastes from common manufacturing and industrial processes, specific industries and can be generated from discarded commercial products. Characteristic wastes are wastes that exhibit any one or more of the following characteristic properties: ignitability, corrosivity, reactivity or toxicity.
A waste that has a hazardous component and a radioactive component is called a mixed waste and is regulated under both the Resource Conservation and Recovery Act (RCRA) and the Atomic Energy Act.
On this page:
Listed Wastes
A waste is determined to be a hazardous waste if it is specifically listed on one of four lists (the F, K, P and U lists) found in title 40 of the Code of Federal Regulations (CFR) in section 261.
The F and K Lists
The F-list, found at 40 CFR section 261.31, identifies wastes from common manufacturing and industrial processes as hazardous. Because the processes generating these wastes can occur in different sectors of industry, the F list wastes are known as wastes from non-specific sources. They can be divided into seven groups depending on the type of manufacturing or industrial operation that creates them:
- Spent solvent wastes,
- Electroplating and other metal finishing wastes,
- Dioxin-bearing wastes,
- Chlorinated aliphatic hydrocarbons production,
- Wood preserving wastes,
- Petroleum refinery wastewater treatment sludges, and
- Multisource leachate.
The K-list identifies hazardous wastes from specific sectors of industry and manufacturing and are considered source-specific wastes. To qualify as a K-listed hazardous waste, a waste must fit into one of the 13 categories on the list and the waste must match one of the detailed K list waste descriptions in 40 CFR section 261.32. the 13 industries that generate K list wastes are:
- Wood preservation,
- Organic chemicals manufacturing,
- Pesticides manufacturing,
- Petroleum refining,
- Veterinary pharmaceuticals manufacturing,
- Inorganic pigment manufacturing,
- Inorganic chemicals manufacturing,
- Explosives manufacturing,
- Iron and steel production,
- Primary aluminum production,
- Secondary lead processing,
- Ink formulation, and
- Coking (processing of coal to produce coke).
Use the table below to search for and sort by hazardous wastes listed on the F and K lists:
*To indicate its reason for listing a waste, EPA assigns a hazard code to each waste listed on the F and K list. An explanation of each of the codes is below:
(T) - Toxic Waste
(H) - Acute Hazardous Waste
(I) - Ignitable Waste
(C) - Corrosive Waste
(R) - Reactive Waste
(E) - Toxicity Characteristic Waste
The first two hazard codes shown above apply to listed wastes whose constituents pose additional threat to human health and the environment. The last four hazard codes apply to wastes that have been listed because they typically exhibit one of the four regulatory characteristics of hazardous waste.
The P and U Lists
The P and U lists designate as hazardous waste pure and commercial grade formulations of certain unused chemicals that are being disposed. For a waste to be considered a P- or U-listed waste it must meeting the following three criteria:
- The waste must contain one of the chemicals listed on the P or U list;
- The chemical in the waste must be unused; and
- The chemical in the waste must be in the form of a commercial chemical product.
EPA defines a commercial chemical product for P and U list purposes as a chemical that is either 100 percent pure, technical (e.g., commercial) grade or the sole active ingredient in a chemical formulation.
The P-list identifies acute hazardous wastes from discarded commercial chemical products. The P-list can be found at 40 CFR section 261.33. The U-list identifies hazardous wastes from discarded commercial chemical products. The U-list wastes can be found at 40 CFR section 261.33.
Use the table below to search for and sort by hazardous wastes listed on the P and U lists:
**For the convenience of the regulated community, the primary hazardous properties of these materials have been indicated by the letters T (Toxicity), R (Reactivity), I (Ignitability) and C (Corrosivity). For wastes on the P list, absence of a letter indicates that the compound only is listed for acute toxicity. For wastes on the U list, absence of a letter indicates that the compound is only listed for toxicity.]
1CAS Number given for parent compound only.
Characteristic Wastes
A hazardous waste characteristic is a property which, when present in a waste, indicates that the waste poses a sufficient threat to merit regulation as hazardous. EPA established four hazardous waste characteristics: ignitability, corrosivity, reactivity and toxicity.
Ignitability
Wastes that are hazardous due to the ignitability characteristic include liquids with flash points below 60 °C, non-liquids that cause fire through specific conditions, ignitable compressed gases and oxidizers. EPA assigned D001 as the waste code for ignitable hazardous wastes.
Test methods for ignitability include the Pensky-Martens Closed-Cup Method for Determining Ignitability (SW-846 Test Method 1010A), the Setaflash Closed-Cup Method for Determining Ignitability (SW-846 Test Method 1020B) and the Ignitability of Solids (SW-846 Test Method 1030). To learn more about the ignitability characteristic see:
- 40 CFR section 261.21, and
- The Ignitability Characteristic Background Document
Corrosivity
Wastes that are hazardous due to the corrosivity characteristic include aqueous wastes with a pH of less than or equal to 2, a pH greater than or equal to 12.5 or based on the liquids ability to corrode steel. EPA assigned D002 as the waste code for i hazardous wastes.
The test method to determine corrosivity towards steel is Corrosivity Towards Steel (SW-846 Test Method 1110A). To learn more about the corrosivity characteristic see:
- The regulations at 40 CFR section 261.22, and
- The Corrosivity Characteristic Background Document.
Reactivity
Wastes that are hazardous due to the reactivity characteristic may be unstable under normal conditions, may react with water, may give off toxic gases and may be capable of detonation or explosion under normal conditions or when heated. EPA assigned D003 as the waste code for reactive hazardous wastes.
There are no test methods for reactivity. To learn more about this characteristic see:
- The regulations at 40 CFR section 261.23, and
- The Reactivity Characteristic Background Document.
Toxicity
Wastes that are hazardous due to the toxicity characteristic are harmful when ingested or absorbed. Toxic wastes present a concern as they may be able to leach from waste and pollute groundwater. The toxicity of a waste is determined by the Toxicity Characteristic Leaching Procedure (TCLP) (SW-846 Test Method 1311). EPA assigned wastes codes D004 through D043 that correspond to a contaminant and its associated TCLP concentration.
To learn more about the toxicity characteristic and regulatory levels for the TCLP test see 40 CFR section 261.24.
Mixed Radiological and Hazardous Waste
Mixed wastes are hazardous wastes which also contain radioactive material. Mixed waste is regulated under the RCRA and the Atomic Energy Act. The hazardous component of the mixed waste is regulated by EPA under RCRA. The radiological component of the mixed waste is regulated by the Department of Energy (DOE) or the Nuclear Regulatory Commission (NRC). The NRC typically regulates waste from commercial and non-DOE facilities while the DOE regulates waste from DOE facilities.
EPA’s Mixed Waste Rule provides increased flexibility to generators and facilities that manage low-level mixed waste (LLMW) and naturally occurring and/or accelerator-produced radioactive material (NARM) containing hazardous waste by exempting these wastes from RCRA storage and treatment requirements. The exemption is conditional upon the waste is generated under a single NRC license, of which the waste meets the specified conditions and that the waste is stored and treated in a tank or container.
More information about the EPA Mixed Waste Rule can be found in the following final rule, final rule fact sheet and proposed rules:
- Final Rule: Storage, Treatment, Transportation and Disposal of Mixed Waste
- Final Rule Fact Sheet
- Proposed Rule: Storage, Treatment, Transportation and Disposal of Mixed Waste
- Advanced Notice of Proposed Rulemaking: Approach to Reinventing Regulations on Storing Mixed Low-Level Radioactive Waste
- Proposed Collection; Comment Request, Treatment, Transportation and Disposal of Mixed Wastes
Additional supporting documents can be found on regulations.gov in the docket for this rule.
Additional Resources
- Final Report of the Study on Spent Solvents
- Study of Selected Petroleum Refining Residuals
- A glossary of terms can be found in Appendix C of the RCRA Orientation Manual.