Frequently Asked Querstions About Mixed Waste (Nuclear and Chemical, Together)

Frequently Asked Questions about Mixed Waste -

Radioactive and Chemical / Hazardous Waste

Mixed waste contains radioactive and hazardous waste. A dual regulatory framework exists for mixed waste, with the U.S. Environmental Protection Agency (EPA) or authorized states regulating the hazardous waste and the U.S. Nuclear Regulatory Commission (NRC).

1. What is mixed waste?

(Question and Answer: RCRA Hotline Report 2/97)

Mixed waste is waste that contains a hazardous waste component and a radioactive material component. A hazardous waste is either listed under 40 CFR Part 261, Subpart D, and/or exhibits a characteristic described in 40 CFR Part 261, Subpart C. Radioactive material must be classified as source, special nuclear, or byproduct material subject to the Atomic Energy Act of 1954 (AEA) (42 U.S.C. Section 201 et seq.).

2. How is mixed waste regulated?

(Question and Answer: RCRA Hotline Report 2/97)

Mixed waste is jointly regulated under both RCRA and the AEA. RCRA regulates the hazardous waste portion of the waste as any other hazardous waste, while the AEA regulates the RCRA-exempt radioactive portion (52 FR 15939; May 1, 1987).

3. Who regulates mixed waste?

(Question and Answer: RCRA Hotline Report 2/97)

Mixed waste is regulated by EPA, the Nuclear Regulatory Commission (NRC), and the Department of Energy (DOE). EPA regulates the hazardous waste portion, while the NRC or DOE regulate the radioactive portion. The NRC typically regulates mixed wastes from commercial and non-DOE federal facilities, while DOE regulates materials from DOE facilities.

4. Who generates mixed waste?

(Question and Answer: RCRA Hotline Report 2/97)

Mixed waste is typically generated by certain federal facilities, nuclear power plants, industrial sites, research laboratories, and medical institutions (Mixed Waste Incineration: (1) Background, EPA402-F-95-004).

5. What are some examples of low-level mixed waste?

(Question and Answer: Definition and Identification of Commercial Mixed Waste, October 4, 1989, National Profile on Commercially Generated Low-Level Radioactive Mixed Waste, December 1992.)

The National Profile on Commercially Generated Low-Level Mixed Waste, a joint survey conducted by DOE's Oak Ridge National Laboratory for EPA and NRC, identified several examples of mixed low-level waste among the 140,000 cu.ft generated in 1990. Among them are:

• Liquid scintillation cocktails. (100,000 cu. ft., 71% of total)
• Organic solvents, corrosive organics, and waste oils (25,200 cu.ft., 18 % of total)
• Toxic metals such as discarded lead shielding (4,200 cu. ft., or 3% of total)
• Other waste streams comprising one or more of the above (11,200 cu. ft., or 8% of total)

This survey indicates that potential commercial mixed low-level waste comprises a small percentage of all low-level waste.

6. Do the land disposal restrictions apply to mixed waste?

(Question and Answer: RCRA Hotline Report 2/97)

Mixed waste, regardless of its type of radioactive element, is hazardous waste and consequently subject to RCRA hazardous waste regulations, including the land disposal restrictions. Treatment standards for hazardous wastes are found in Section 268.40 of the RCRA regulations. In some cases special treatment standards are listed for mixed wastes, such as for radioactive lead solids (D008) and elemental mercury contaminated with radioactive materials (D009). When no special standards are listed, the normal treatment standards for the particular waste code apply (55 FR 22644; June 1, 1990).

7. How are any inconsistencies that may arise between RCRA and AEA regulation resolved?

(Question and Answer: RCRA Hotline Report 2/97)

Section 1006 of the RCRA statute provides that if application of both RCRA and AEA regulations creates a conflict, the AEA regulation would take precedence to the extent of the inconsistency between the regulations (OSWER Directive 9541.00-6; also 52 FR 15940; May 1, 1987).

8. Are my low-level radioactive wastes exempt from RCRA because they are source, special nuclear, or byproduct materials as defined by the AEA?

(Question and Answer: Definition and Identification of Commercial Mixed Waste, October 4, 1989)

Except for certain ores containing source material, which are defined as source material in 10 CFR 40.4(h), and uranium and thorium mill tailings or wastes, NRC and EPA consider that only the radionuclides themselves are exempt from RCRA. Section 1004(27) of RCRA excludes source, special nuclear, and byproduct material from the definition of "solid waste." Since "hazardous waste" is a subset of "solid waste", RCRA also excludes source, special nuclear, and byproduct materials from the definition of hazardous waste and, therefore, from regulation under EPA's RCRA Subtitle C program. Section 11 of the AEA as amended.

Source, special nuclear, and byproduct materials, however, may be mixed with other radioactive or non-radioactive materials that are not source, special nuclear, or byproduct materials. For example, tritium (H-3) may be contained in toluene, a nonhalogenated aromatic solvent. Consistent with the definition of byproduct material, the tritium may be considered a byproduct material, while the toluene that contains the tritium would not be byproduct material. Mixtures of toluene and tritium could satisfy the definition of mixed low-level waste because they contain listed hazardous waste (spent toluene) and tritium that may qualify as low-level waste if it has been produced by activities regulated by NRC under the AEA.

9. If I use chemicals in my process that are identified by EPA as hazardous constituents should I assume that my LLW is LLMW?

(Question and Answer: Definition and Identification of Commercial Mixed Waste, October 4, 1989)

No. Low-level radioactive waste that contains hazardous constituents may not necessarily be mixed low-level waste. As defined above, mixed low-level waste is low-level waste that contains a known hazardous waste (i.e., a listed hazardous waste) or that exhibits one or more of the hazardous characteristics because it contains non-AEA materials. For wastes that are not listed in Subpart D of 40 CFR Part 261, testing is not necessarily required to "determine" whether the low-level wastes exhibits any of the hazardous characteristics. A generator may be able to determine whether that low-level waste is mixed low-level waste based upon knowledge of the waste characteristics or the process that generates the low-level waste.

Furthermore, if the generator normally segregates low-level waste from hazardous and other types of wastes, there is no need to assume that hazardous wastes may have been inadvertently mixed with low-level waste or to inspect each container or receptacle to ensure that inadvertent mixing has not occurred. Although the generator is subject to RCRA inspections and must follow the manifest, pre-transport, and other requirements of 40 CFR 262, the generator is not required to demonstrate that every low-level waste container does not contain hazardous waste.

10. How can I obtain representative samples of heterogeneous trash included in LLW to perform hazardous characteristic tests?

(Question and Answer: Definition and Identification of Commercial Mixed Waste, October 4, 1989)

Before discussing the collection of representative samples of wastes, generators are reminded that they are not required to test low-level waste to determine if the waste contains hazardous wastes. Generators and handlers of mixed waste and hazardous waste can declare their wastes hazardous or nonhazardous based on knowledge of the process/production of the waste, in lieu of testing for a characteristic. Representative samples of waste should be collected for testing in accordance with EPA's regulations in 40 CFR 261.20(c), which state that waste samples collected using applicable methods specified in Appendix I of part 261 will be considered as representative samples for hazardous characteristics testing.

11. If a generator treats a prohibited characteristic mixed waste, i.e., a waste that is both hazardous and radioactive, and it is no longer hazardous, should the one-time notification and certification still be sent to the EPA Region or to the authorized state if the waste is being sent to an Atomic Energy Act (AEA) landfill?

(Question and Answer: RCRA Hotline Report 1/97)

The land disposal restrictions (LDR) in 40 CFR Part 268 require that hazardous waste prohibited from land disposal meet treatment standards before it is placed in a landfill. A prohibited characteristic waste that has been treated to meet LDR standards (and to eliminate the haracteristic) may exit Subtitle C hazardous waste regulation and be sent to a Subtitle D facility, provided the generator sends a one-time notification and certification to the EPA Region or authorized state (Section 268.9(d)).

The one-time notification and certification should still be sent to the EPA Region or authorized state. The one-time notification and certification verifies that the waste has been treated to meet all applicable LDR standards and indicates the site of ultimate disposal since the waste is no longer subject to Subtitle C regulation. RCRA Section 4004 specifically prohibits the open dumping of solid waste. If the AEA landfill meets the Subtitle D criteria under 40 CFR Parts 257 or 258, which distinguish between sanitary landfills and open dumps, then the decharacterized mixed waste may be sent to that facility.

12. How does EPA enforce the RCRA Section 3004(j) storage prohibition at non-DOE and commercial facilities currently storing mixed waste in violation of this provision?

(Question and Answer: RCRA Hotline Report 2/98)

RCRA Section 3004(j) prohibits the storage of any prohibited hazardous waste, including radioactive mixed waste, except for the purpose of accumulating quantities necessary to facilitate proper waste recovery, treatment, or disposal (Section 268.50). A "prohibited" hazardous waste is a waste ineligible for land disposal unless it meets the land disposal restrictions treatment standards found in Section 268.40 and is currently subject to those standards. EPA has concluded that when no viable treatment for the waste exists, storage of a waste pending development of such treatment technology does not constitute storage to accumulate sufficient quantities to facilitate proper treatment or disposal (61 FR 18588; April 26, 1996). While the Federal Facility Compliance Act of 1992 (FFCA) did exempt certain Department of Energy (DOE) facilities storing mixed waste from Section 3004(j), it did not exclude non-DOE and commercial facilities.

In response to the current lack of treatment and disposal capacity for mixed waste, EPA has established an enforcement policy for facilities storing mixed waste in violation of the RCRA Section 3004(j) storage prohibition (56 FR 42730; August 29, 1991). The policy states that commercial facilities storing mixed waste in violation of Section 3004(j) due to a lack of available treatment or disposal capacity are considered by EPA to be a reduced or low priority among potential civil enforcement actions as long as the waste is managed in an environmentally responsible manner. The enforcement policy applies only to those facilities generating small amounts of mixed waste. EPA believes a facility is managing its mixed waste in an environmentally responsible manner when it can demonstrate that it has: conducted an inventory of the facility's mixed waste storage areas to assess and assure compliance with all other applicable RCRA storage standards; identified and maintained records of all mixed wastes generated; developed and implemented, where feasible, a mixed waste minimization plan; and documented good faith efforts to find available treatment technologies and disposal capacity for its stored mixed waste. The enforcement policy does not apply to prohibited mixed wastes for which treatment technology or disposal capacity exists, or becomes available prior to April 1998.

EPA's primary enforcement concern is with violations of Section 3004(j) by generators who are storing mixed wastes for which treatment or disposal capacity is available, or who are not managing their waste in an environmentally responsible manner. It is important to note that the enforcement policy applies only to civil judicial and administrative enforcement, and does not extend to criminal violations of RCRA, for which the U.S. Attorney General has sole prosecutorial discretion.

The original enforcement policy was scheduled to terminate on December 31, 1993, with the provision that EPA may renew it beyond 1993 if necessary. Since that time, EPA has extended the enforcement policy twice. The first extension, in 1994, extended the policy for two years, until April 20, 1996 (59 FR 18813; April 20, 1994). This extension did not apply to executive branch federal facilities, as these facilities were still eligible for the FFCA's three-year delay of the waiver of sovereign immunity. The second extension came in 1996 and set the expiration date of April 20, 1998 (61 FR 18588; April 26, 1996). Since the FFCA three-year delay has expired, the enforcement policy now applies to executive branch federal facilities other than DOE and joint Navy/DOE Naval Nuclear Propulsion Program (NNPP) facilities.

13. Does the waiver of sovereign immunity mean that federal facilities are subject to all state regulations, including those that are broader in scope than the federal rules?

(Question and Answer: RCRA Hotline Report 7/98)

RCRA Section 271.1(i)(2) explains that state rules, which have a greater scope of coverage than the federal law (i.e., are broader in scope), are not part of the federally approved program. However, the Solid Waste Disposal Act (SWDA) and the Federal Facility Compliance Act (FFCA) waived all sovereign immunity for federal facilities, making them subject to all federal, state, interstate, and local requirements concerning the disposal and management of solid and hazardous waste.

RCRA Section 6001(a) waives sovereign immunity for federal facilities with respect to federal, state, and local solid and hazardous waste disposal and management requirements, including those solid and hazardous waste requirements that are more stringent or broader in scope than the federal RCRA provisions. The FFCA also amended Section 6001 to clarify that federal facilities are subject to civil and administrative penalties associated with these requirements. Therefore, federal facilities are subject to and must comply with federal, interstate, and local requirements regarding solid and hazardous waste disposal and management, including those that are broader in scope than the federal rules.

14. Are NORM wastes, which are also RCRA hazardous wastes, subject to regulation as a mixed waste?

(Question and Answer: RCRA Hotline Report 9/98)

Mixed wastes are wastes which contain a hazardous waste component, regulated under RCRA, and a radioactive waste component, regulated under the Atomic Energy Act (AEA) of 1954. Naturally occurring radioactive materials (NORM) are materials, usually from mineral extraction or processing activities, whose natural radioactivity has been technologically enhanced. NORM does not describe the natural radioactivity of rocks and soils or background radiation, but those materials whose naturally occurring radiation has been enhanced by some human process or activity.

NORM is a subset of naturally occurring or accelerator-produced radioactive materials (NARM). The definition of NARM includes both radioactive materials produced by an accelerator used in sub-atomic particle physics research, and NORM. Neither NORM nor NARM is regulated under the AEA. EPA believes that because NORM is not regulated under the AEA, a NORM waste that is also a RCRA hazardous waste does not meet the definition of a mixed waste (55 FR 22520, 22645; June 1, 1990.) Such a waste, therefore, would be regulated only as a hazardous waste under RCRA, and not a mixed waste under both RCRA and AEA.