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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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Mixed Waste Standards and the LDR Storage Prohibition

Mixed waste is defined as a mixture that contains both hazardous waste and radioactive materials (i.e., source, special nuclear, or by-product material) subject to the Atomic Energy Act (AEA). The hazardous waste components are subject to the same LDR treatment standards as any other hazardous waste. [§268.42(d)] The real problem with mixed wastes is that limited treatment and disposal capacity is available for dealing with these wastes.

Mixed wastes at DOE facilities

Because of a lack of treatment capacity, large quantities of mixed wastes are in long-term storage at Department of Energy (DOE) facilities awaiting the development of additional capacity. This extended storage of mixed wastes was made possible by the Federal Facilities Compliance Act (FFCA) of 1992 (Public Law 102-386). This law allowed DOE to continue storing mixed waste as long as 1) the waste is managed in accordance with other applicable requirements; and 2) an existing permit, agreement, or administrative/judicial order does not apply to the waste. DOE facilities were required to develop site treatment plans for treating mixed wastes so they can be disposed of in accordance with the LDR program. EPA subsequently approved these plans and, in essence, DOE facilities have sovereign immunity from violations of the LDR storage prohibition as long as they are in compliance with their plan. [RO 14416]

Waste treatment subcategories have been developed for seven types of mixed wastes:

  1. D002 and D004–D011 radioactive high-level wastes generated during the reprocessing of fuel rods,
  2. D006 radioactive cadmium-containing batteries,
  3. D008 radioactive lead solids,
  4. D009 elemental mercury contaminated with radioactive materials,
  5. D009 radioactive hydraulic oil contaminated with mercury,
  6. D009 radioactive mercury-containing batteries, and
  7. D011 radioactive silver-containing batteries.

All other radioactive mixed wastes are subject to the treatment standards that apply to the hazardous portion of the waste.

Mixed wastes at commercial sites

Mixed wastes generated at commercial sites (power plants, hospitals, laboratories, etc.) are also subject to the LDR program. However, the long-term storage allowed at DOE sites by the FFCA does not apply to these facilities. Instead, EPA issued a “Policy on Enforcement of RCRA Section 3004(j) Storage Prohibition at Facilities Generating Mixed Radioactive/Hazardous Wastes.” [August 29, 1991; 56 FR 42730] This policy, last extended to October 31, 2001 [November 6, 1998; 63 FR 59989], says enforcement of the storage provision for radioactive mixed wastes will be a low priority for commercial generators who produce <1,000 cubic feet per year of mixed waste provided the mixed waste is managed in an environmentally responsible manner.

Much of the pressure on commercial generators of mixed waste was relieved by a May 16, 2001 rule. [66 FR 27218] This rule allows NRC-licensed facilities to store mixed waste in tanks and containers in compliance with NRC license conditions. Wastes stored under these conditions are conditionally exempt from RCRA. When these wastes are ultimately disposed of, however, they must meet LDR treatment standards.

A drained lead-acid battery is radioactively contaminated. Would the battery be subject to the lead-acid battery treatment standard (lead recovery), or the radioactive lead solids treatment standard (macroencapsulation)?

According to EPA, “the appropriate treatment standard is macroencapsulation. This treatment standard applies not only to lead shielding, but to other elemental forms of lead. Thus, there is latitude in the treatment standard to permit its application to radioactive lead-acid batteries. We also believe that macroencapsulation is appropriate because it would require less worker handling than lead recovery, and we want to minimize worker exposure to radioactivity. Furthermore, lead recovery of these batteries would radioactively contaminate the entire mass of lead that was recovered, making it unusable.” [RO 14554]

Mercury-contaminated soils (>260 mg/kg mercury) are also contaminated with low-level radioactive material. The LDR treatment standard for this waste is RMERC (recovery of mercury); however, any mercury recovered from this waste will be unusable because it will be radioactive. Therefore, this recovered mercury will have to be disposed of and will fit into a different D009 subcategory—elemental mercury contaminated with radioactive materials. The treatment standard for this waste is amalgamation (AMLGM). Are any other options available to the generator of this waste?

Yes. The generator may submit an application to EPA for approval of an alternative treatment method as described in §268.42(b). In this specific case, the generator followed these procedures and was granted an alternative treatment standard of 0.2 mg/L TCLP for mercury. [RO 14270]

Submarine reactor compartments consist of radioactive components, surrounded by lead shielding, all of which is encased in a thick, sealed steel jacket. Do the compartments, as generated, meet the D008 radioactive lead solids treatment standard of macroencapsulation (MACRO), and is any testing for leachable lead required?

The definition of MACRO in §268.42 specifically allows for a “jacket of inert inorganic materials,” such as a steel jacket. Due to size and structure, the jacket does not meet the definition of a drum or container; therefore, it meets the standard of MACRO. Furthermore, this is a technology-based standard and does not require a TCLP analysis for lead. Such an analysis would require crushing or grinding of components of the reactor compartments, and could pose a high radiation exposure risk. Avoiding these risks was the whole purpose of establishing the MACRO standard. [RO 13393]

What is the treatment standard for D008 radioactive lead solids that happen to be tanks or containers?

Although the MACRO standard cannot be met by placing radioactive lead solids in a tank or container, if the solids are themselves tanks or containers, they may be treated with an application of surface coatings or jacketing to reduce exposure to leaching media. [RO 14091]

Plastic-coated, lead lined gloves will be disposed of as D008 radioactive lead solids. Do they comply with the MACRO standard as generated?

Yes. Provided none of the lead is exposed (i.e., the entire surface of the lead is coated) and the coating provides a substantial reduction in surface exposure to potential leaching media, the LDR standard is met at the point of generation. [RO 13437]

A commercial facility that generates mixed waste is relying on EPA’s low-enforcement-priority policy to continue storing the waste. If a legitimate recycling facility is now able to recycle the waste, can the commercial facility continue to store the mixed waste?

No. The enforcement policy does not extend to generators who do not avail themselves of legitimate recycling (or treatment) opportunities. [RO 14101, 14171]

The LDR storage prohibition

Because treating wastes to meet LDR standards can be relatively expensive, EPA was concerned that generators would be tempted to put their wastes into indefinite storage to avoid these costs. To forestall this activity, the agency promulgated a storage prohibition in §268.50. A generator may accumulate wastes onsite in tanks, containers, or containment buildings “solely for the purpose of the accumulation of such quantities of hazardous waste as necessary to facilitate proper recovery, treatment, or disposal.” [§268.50(a)(1)]

A similar storage prohibition applies to TSD facilities in §268.50(a)(2). A one-year time limit is imposed on such storage. (Such waste storage at TSD facilities is subject to permitting.) During this one-year storage period, the appropriate regulatory agency has the burden of proof to show that storage is not “necessary” as described above. After the one-year storage period expires, the burden of proof shifts to the TSD facility. Hence, storage of wastes subject to LDR standards for more than one year is allowed only for good cause.

The federal regulations do not specify how long wastes can remain in a satellite accumulation area (if the 55-gallon/1-quart/1-kilogram limits aren’t exceeded). Conceivably, wastes might accumulate for several years before the quantity limit is reached. A regulatory concern can arise under these circumstances because of the above-mentioned storage prohibition. When a hazardous waste is generated, it is subject to LDR, including §268.50, which states that if a waste is stored for more than one year, the burden of proof is on the owner/operator to show why this is necessary. In 1990 guidance, however, EPA clarified that the accumulation time for the LDR storage prohibition starts when the waste is moved to a central accumulation area (i.e., a 90/180/270-day or permitted area). Therefore, EPA’s perspective is that hazardous waste accumulation in satellite accumulation areas is not subject to the one-year storage prohibition. [OSWER Directive 9555.00-01]

The storage prohibition doesn’t apply to certain wastes:

  1. Wastes subject to a case-by-case extension, no-migration exemption, or national capacity variance [§268.50(d)];
  2. Wastes that meet LDR treatment standards [§268.50(e)]; and
  3. Remediation wastes stored in a staging pile [§268.50(g)].

If a facility is storing wastes subject to the LDR standards for more than one year, is it required to notify the regulatory agency of this storage?

For storage more than one year, the burden is on the facility owner or operator to demonstrate such storage time is necessary. The owner/operator does not have to notify the agency of storage in excess of one year. The burden of proof only applies in the event of an EPA inspection or for enforcement purposes. [RO 12845, 12851]

A characteristic hazardous waste has been treated to remove the characteristic and is being stored at a TSD facility. Even though the waste is no longer hazardous, UHCs have not been treated to meet treatment standards. Is the waste still subject to the LDR storage prohibition?

The waste remains subject to the storage prohibition even though it is no longer hazardous. Because the LDR treatment standards apply at the point of generation, the storage prohibition applies until the waste is treated to fully meet the standards. One year after the waste was originally generated, the facility storing the waste will have the burden of proving the waste is still being stored to facilitate proper recovery, treatment, or disposal. [RO 14048]

Lead-acid batteries to be recycled are stored on an earthen pad. Is this allowable under the LDR storage prohibition, or must the batteries meet treatment standards (lead recovery) before being placed on the pad?

Wastes may be stored in tanks, containers, or containment buildings without meeting treatment standards. The shell surrounding an intact lead-acid battery is considered to be a container. Therefore, as long as the batteries are being stored for the purpose of facilitating proper recovery, treatment, or disposal (as specified in §268.50), the storage is allowable. The batteries do not have to meet treatment standards before being stored. [RO 13339]

Mercury Export Ban Act

The Mercury Export Ban Act (MEBA or the Act, Public Law No. 110-414), which became law on October 14, 2008, is intended to reduce the availability of elemental mercury in domestic and international markets. With a few exceptions, the export of elemental mercury from the United States has been prohibited effective January 1, 2013. To avert unsafe accumulation of waste elemental mercury, the Act requires DOE to designate a facility to be used for long-term storage of waste elemental mercury generated in the United States. On December 6, 2019, a DOE Record of Decision designated a site near Andrews, Texas as the location of the repository. [84 FR 66890] However, on October 6, 2020, DOE withdrew that designation. [85 FR 63105] More information on DOE’s program for the long-term management and storage of elemental mercury can be found at

This ban can directly affect hazardous waste TSD facilities that manage waste elemental mercury. Here’s how.

The LDR treatment standard for the high-mercury subcategories of D009 and U151 is recovery of mercury via roasting or retorting. The concept when this treatment standard was set in the early 1990s was that the mercury would be recovered and reused rather than land disposed. However, domestic uses for mercury are declining. Therefore, since the effective date of the MEBA, elemental mercury recovered by mercury recovery facilities will likely have to be stored as hazardous waste. In general, storing hazardous waste for longer than one year is prohibited under the LDR storage prohibition in §268.50. However, under MEBA, the storage prohibition does not apply to elemental mercury being stored in the yet-to-be-designated DOE repository. The Act also allows elemental mercury to be stored for longer than one year at any RCRA-permitted TSD facility under the following conditions:

  1. DOE is unable to accept the mercury at its yet-to-be-designated repository for reasons beyond the control of the owner/operator of the TSD facility,
  2. The owner/operator of the TSD facility certifies in writing it will ship the mercury to DOE’s repository once it can accept the mercury, and
  3. The owner/operator of the TSD facility certifies it will not sell or otherwise place the mercury in commerce.

Mercury waste retort operations generate a surplus of unsaleable elemental mercury. This surplus mercury will be disposed of in DOE’s yet-to-be-designated long-term elemental mercury repository. What is the RCRA status of this elemental mercury?

The recovered elemental mercury is a listed hazardous waste, coded U151. [RO 14934]

A 2020 report, titled Inventory of Mercury Supply, Use, and Trade in the United States, is available at


Topic: Are Remediation Wastes Hazardous?

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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.