U.S. EPA Mixed Waste Team

Regulatory History of Mixed Waste


Resource, Conservation, and Recovery Act (RCRA) gives EPA the authority to regulate hazardous waste from "cradle-to-grave." However, RCRA specifically excludes source, special nuclear, or byproduct material as defined by the Atomic Energy Act of 1954 from the definition of solid waste. Hazardous waste is a subset of solid waste. Therefore source, special nuclear, and by-product materials are not considered hazardous under RCRA. In the event that AEA and RCRA are found to be inconsistent, AEA will take precedence.


NRC recognizes joint regulation for mixed waste in rulemaking to establish land disposal regulations for radioactive waste (10 CFR 61.56 (a)(8)) "Waste containing hazardous, biological, pathogenic, or infectious material must be treated to reduce to the maximum extent practicable the potential hazard from the non-radiological materials."


In LEAF vs. Hodell, the court mandated that RCRA applied to DOE's hazardous waste but was unclear with respect to source, special nuclear, and by-product material.

Hazardous Solid Waste Amendments to RCRA increase the stringency of hazardous waste requirements.


EPA publishes notice clarifying RCRA jurisdiction for mixed waste and indicates that States must include mixed waste in RCRA base authorization (July 3rd, 51 FR 24504). This action tied mixed waste to the HSWA Land Disposal Restrictions.

Land Disposal Restrictions for California-listed hazardous wastes were promulgated by EPA.


NRC & EPA publish draft joint guidance on the definition and identificatin of LLMW. (1/87; revised on 10/89)

NRC & EPA publish joint guidances on siting guidelines for disposal of LLMW and a conceptual design approach for a commercial LLMW disposal facility.

EPA promulgates LDR standards for solvents and dioxins.

DOE clarifies its position on the definition of by-product material (May 1, 1987: 52 FR 15937). This clarification applies only to 11(e)1 by-product material. According to this clarification, only the actual radionuclides, not the entire waste stream, are considered by-product material; and thus, RCRA has authority to regulate the hazardous portion of the waste stream.

DOE Order 5400.3, Hazardous and Radioactive Mixed Waste Programs, establishes policies guidelines and minimum requirements under which DOE facilities must manage their radioactive and mixed waste and contaminated facilities. Order 5400.3 excludes by-product material from the definition of mixed waste unless it is mixed with RCRA hazardous waste.


DOE Order 5820.2A, Management of Defense LLW, establishes policies for handling LLW. Under Order 5820.2A, Chapter IV, all DOE waste containing Naturally Occurring or Accelerator Produced Radioactive Materials (NARM) shall be managed as hazardous waste under the authority of RCRA.

EPA publishes a notice which clarifies requirements for facilities that treat, store, or dispose of radioactive mixed waste to obtain interim status pursuant to Subtitle C of RCRA. Additionally this notice addresses "notification" requirements for handlers of radioactive mixed waste. (September 23, 1988: 53 FR 37045)

EPA publishes hazardous waste injection restrictions that include restrictions for mixed waste (July 26, 1988 : 53 FR 28154). 40 CFR 148.16(d) reads "Effective August 8, 1990, mixed radioactive/hazardous waste in 40 CFR 268.10, 268.11, and 268.12, that are mixed radioactive and hazardous wastes, are prohibited from underground injection."


EPA promulgates the last third of the HSWA mandated requirements including alternative standards for four groups of mixed waste:

  • Vitrification of HLW from reprocessing spent nuclear fuel
  • Microencapsulation of lead solids
  • Amalgamation of elemental mercury
  • Incineration of mercury in hydraulic oils

A conditional 10 year no-migration variance for limited amount of untreated waste for the purposes of testing and experimentation was granted to the DOE WIPP facility (55 FR 47700, November 14, 1990).

Superfund's 1990 National Oil and Hazardous Substances Pollution Contingency Plan (NCP) addresses radioactive and mixed waste in the Hazard Ranking System (HRS) [December 14, 1990 : 55 FR 51583]. "In general, sites containing mixed radioactive and other substances involve more evaluation than sites containing only radionuclides," (40 CFR 300, Appendix A, 7.0).


EPA issued a policy of giving a reduced priority to civil enforcement of the RCRA storage prohibition. This was based upon a determination that there is inadequate treatment capacity available for these wastes. The waste covered under this variance must be stored in accordance with RCRA requirements until treatment or disposal capacity becomes available.

October 6, 1992, Congress establishes a definition of "mixed waste" in Federal Facilities Compliance Act (RCRA 1004 (41), 42 USC 6903 (41)). This act also clearly waives DOE and other Federal Facilities' immunity from EPA and State hazardous waste regulations and sanctions. DOE is also required to develop a Site Treatment Plan for each DOE facility to map out a compliance strategy with these regulations. The deadline for these plans was October 6th, 1995.

As detailed in 40CFR268.35(d) "Effective May 8, 1992, hazardous wastes listed in 40 CFR 268.10, 268.11, and 268.12 that are mixed radioactive/hazardous wastes, and soil or debris contaminated with hazardous wastes listed in 40 CFR 268.10, 268.11, and 268.12 that are mixed radioactive/hazardous wastes, are prohibited from land disposal."


In April EPA extended policy of giving a reduced priority to civil enforcement of the RCRA strorage prohibition for two years.

Subpart CC regulations for emission standards for tanks, surface impoundments, and containers are published in the Federal Register (December 6, 1994: 59 FR 62927). The requirements of this subpart do not apply to a waste management unit that is used solely for the management of radioative mixed waste in accordance with all applicable regulations under the authority of the Atomic Energy Act and the Nuclear Waste Policy Act.(40CFR264.1080(b)(6))


In August, EPA/NRC published "Draft Guidance on the Storage of LLMW." This guidance is designed to assist persons currently storing mixed waste to meet the regulatory requirements of both the AEA and RCRA. The guidance describes procedures that are generally acceptable to both NRC and EPA and resolves issues of concern which have been identified to the agencies by licensees and generators.

The proposed Hazardous Waste Identification Rule for process waste is published by the EPA on December 21. This proposal, yet to be finalized, sets an exit level below which a listed hazardous waste would no longer be considered hazardous. Under this proposal mixed wastes with listed hazardous constituents below the exit levels would only be considered radioactive wastes.


On January 22, NRC published in the Federal Register (61 FR 1608-1625) the "Draft Technical Position of Cesium-137 Contaminated Emission Control Dust and other Incident Related Materials" for a 60 day public comment period. The position provides the policy and technical bases for supporting a potential decision, by appropriate regulatory authorities and others, to dispose of a specifically defined mixed waste in hazardous waste disposal facilities not licensed under the Atomic Energy Act.

EPA announced in the April 26th edition of the Federal Register (61 FR 18588-18592) a limited extension of its "Policy on Enforcement of RCRA Section 3004(j) Storage Prohibition at Facilities Generating Mixed Radioactive/Hazardous Wastes" until April 20, 1998. The extension confirms that storage of mixed waste subject to LDRs is unlawful under the section 3004(j) storage prohibition even in the absence of treatment and disposal capacity. The policy states, however, that violators who 1) are faced with an impossibility of complying with the RCRA regulations and 2) are storing their wastes in an environmentally responsible manner will be a low enforcement priority for EPA.


The U.S. Nuclear Regulatory Commission (NRC) published, "Final Technical Position of Cesium-137 Contaminated Emission Control Dust and other Incident Related Materialsts." [March 19, 1997 : 62 FR 13176] The position provides the bases that, with the approval of appropriate regulatory authorities (e.g., State-permitting agencies) and others (e.g., disposal site operators), and with possible public input, could be used to allow disposal of stabilized waste at Subtitle C, RCRA-permitted, hazardous waste disposal facilities. The final position can be downloaded (624 kBytes, Adobe PDF).

EPA temporarily suspends the call-in and processing of RCRA Part B applications and the issuance of RCRA permits for facilities which have interim status for the on-site storage of commercial mixed wastes. This permit suspension only applies where the facility is not otherwise subject to RCRA permitting requirements. Moreover, OSW does not recommend any suspension for facilities where Regions or States find a particular environmental concern that merits the call-in or issuance of such a permit. This will eliminate a potentially needless expenditure of resources while EPA evaluates a possible exemption. The full text of the May 21, 1997 letter from EPA's Office of Solid Waste to EPA Regions and Authorized State RCRA programs with mixed waste authorization can be downloaded (8.8 kBytes, Adobe PDF). The April 7, 1997 letter to Douglas H. Green is also available (5.7 kBytes, Adobe PDF).

The Nuclear Regulatory Commission (NRC) and the Environmental Protection Agency (EPA) have jointly published final guidance on the testing requirements for mixed radioactive and hazardous waste (mixed waste) in the Federal Register on November 20, 1997 (62 FR 62079 - 62094). The full text of the EPA/NRC Mixed Waste Testing Guidance can be downloaded (285 kBytes, Adobe PDF).


EPA has extended its interim extension of its policy (61 FR 18588, April 26, 1996) on the civil enforcement of the storage prohibition in section 3004(j) of the Resource Conservation and Recovery Act (RCRA) at facilities that generate ‘‘mixed waste.’’ This action (effective April 21, 1998) extends the April 1996 policy until October 31, 1998. The policy affects only mixed wastes that are prohibited from land disposal under the RCRA land disposal restrictions and for which there are no available options for treatment or disposal. The full text of this extension (63 FR 17414, April 9, 1998) can be found at the following Federal Register notice [Adobe PDF, 12 kBytes].

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Last Updated: April 9, 1998.