An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Radiation Protection

Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings (40 CFR Part 192)

On this page:

Rule Summary

This regulation sets standards for the protection of public health, safety and the environment from radiological and non-radiological hazards associated with uranium and thorium ore processing, and disposal of associated wastes. The cross-media standards apply to pollution emissions and site restoration. EPA issued the standards in response to the statutory requirements of the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA).

The U.S. Nuclear Regulatory Commission (NRC) and their Agreement States use these standards in their oversight of uranium and thorium facility operations and in issuing licenses for source materialHelpsource materialUranium, thorium or any combination of them. Includes ores that contain, by weight, one-twentieth of 1 percent (0.05 percent), or more, of uranium, thorium, or any combination of them.. The U.S. Department of Energy (DOE) uses the standards in their management of closed uranium mills and in the cleanup of contaminated soil and buildings.

Uranium extraction facilities are those which produce 11(e)(2) byproduct material Help11(e)(2) byproduct material A legal definition from the Atomic Energy Act. The tailings or wastes produced by the extraction or concentration of uranium or thorium from any ore processed primarily for its source material determined by the U.S. Nuclear Regulatory Commission, including mills, in-situ recoveryHelpin-situ recoveryA process to recover uranium in which fluids are injected into ground water to mobilize the uranium in underground deposits. Extraction wells then collect the groundwater, which is processed at the surface to recover the uranium. (ISR) facilities and heap leach facilities. Conventional underground or surface (open pit) mines and their associated wastes are not included.

Rule History

Memorandum of Understanding with the Nuclear Regulatory Commission (NRC)

In 2020, the EPA and the Nuclear Regulatory Commission (NRC) signed a Memorandum of Understanding (MOU) for coordination and cooperation in the regulation of the in-situ recovery (ISR) process of uranium extraction. The MOU provides the EPA and the NRC with a framework for implementing their individual statutory responsibilities with respect to the regulation of ISR activities.

Proposed Revisions in 2015 and 2017

The standards were originally issued in 1983 and have been amended several times. The rule was last amended in 1995.

In January 2015, EPA proposed an amendment to the rule that would have regulated byproduct materials produced by ISR activities with a primary focus on groundwater protection and restoration. The proposed rule would have set post-restoration groundwater standards and would have added monitoring requirements for ISR facilities. After reviewing public comments on the proposal and new information, the Agency decided not to finalize the 2015 proposed rule. In January 2017, EPA issued another proposed rule with groundwater standards and monitoring requirements for ISR facilities.

In October 2018, EPA withdrew the January 2017 proposed rule because of issues raised in the public comment period and because the once anticipated influx of new ISR license applications is not likely to materialize.

View Proposed Rulemaking and Background Documents for the 2015 and 2017 Proposals.

EPA Science Advisory Board Review, 2012

In 2012, the EPA Science Advisory Board (SAB) reviewed a draft report on post-closure monitoring of uranium at in-situ recovery (ISR) sites. The SAB advised expanding this draft report into a Background Information Document for the development of standards for in-situ recovery facilities.

View information related to the Science Advisory Board Advisory topic, "Uranium In-Situ Leach Recovery - Post-closure Stability Monitoring."

Background and Supporting Documents for the 1995 Rule