Jump to main content.

Naturally-Occurring Radiation: 

Laws and Regulations


EPA has used its authority under a number of existing environmental laws to regulate some sources of Technologically-Enhanced Naturally-Occurring Radioactive Materials (TENORM).

Most radionuclides are regulated under the authority of the Atomic Energy Act (AEA). However, the AEA does not cover TENORM unless it is specifically designated as source material, such as high grade uranium and thorium ore. Uranium and thorium mill tailings are also regulated under the AEA.

As early as the mid-1970's, EPA began conducting studies to assess the risk to human health and the environment from industrial releases of materials that are now categorized as TENORM. We consulted with nationally recognized scientific organizations as we designed and conducted studies and analyzed the results.:

EPA used the information gained in those studies, as well as information provided by national and international experts and radiation protection organizations, as the basis for developing TENORM regulations. While other laws may apply, the environmental laws discussed on this page are the bases for existing TENORM regulations.

On this page:

Clean Air Act (CAA)

EPA used the CAA to develop National Emission Standards for Hazardous Air Pollutants (NESHAPS) limit releases of TENORM to the air from both the phosphate industry and uranium mines.

Top of page

Phosphate and Fertilizer Industries

Elemental Phosphorous Facilities

Phosphate ore naturally contains radionuclides. During processing they are released from the ore and concentrated. To better understand releases of this type of TENORM from elemental phosphorous plants, EPA conducted extensive radiological surveys of airborne releases at three plants. The survey identified significant amounts of the radionuclides polonium-210 and lead-210, which become airborne when volatilized by the high temperatures in the process.

The survey also found significant amounts of radium in the slag. Because the radium was encapsulated in the slag, it emitted very little radon. However it did emit gamma rays at a level 15 times the background. Exposure to this level of radiation is hazardous.

EPA issued a NESHAP that regulates polonium-210 emissions from elemental phosphorus plants. A separate standard for lead-210 was unnecessary, because controls for polonium also control lead-210.The gamma radiation is regulated under other laws but is not classified as a "hazardous air pollutant" in the CAA.

Phosphogypsum Stacks

Phosphogypsum is a the primary byproduct of the wet-acid process for producing phosphoric acid from phosphate rock. It is largely calcium sulfate and has been given the name phosphogypsum. (Gypsum is the common trade name for calcium sulfate, a common building material.)

Phosphate rock naturally contains radium, uranium, thorium, polonium, and lead in concentrations that vary from place to place. To protect human and environmental health, the EPA required the placement of phosphogypsum wastes in isolated "stacks" or piles. There are about sixty-three phosphogypsum stacks in the United States, ranging in size from 2 to almost 300 hectares, and from 3 to about 60 meters high. After an extensive study, EPA found that the radon released from the stacks present low levels of risk to millions of people. Subsequently, a NESHAP standard was promulgated to regulate radon emissions from phosphogypsum stacks.

Top of page

Uranium Mines

Surface Uranium Mines

Until the early 1960s, uranium was commonly mined in open pit mines from ore deposits near the surface. During this process, the topsoil (overburden) is piled on land beside the pit and saved for reclamation. The large surface area created by the pit and overburden, both of which contain elevated levels of radium, allowed higher than normal radon emissions to be released into the atmosphere.

In 1988, EPA surveyed two active mines in Texas and Wyoming and 25 inactive mines in Arizona, New Mexico, Colorado, South Dakota, Texas, and Wyoming and determined health risk to be very low. Since these mines were already regulated by state and federal mine reclamation laws and there was no reason to believe that new mines would be constructed since the industry was depressed, EPA decided not to set a NESHAP regulating emissions from surface mines.;

Underground Uranium Mines

EPA conducted a site-by-site assessment of operating or operable underground uranium mines, and found that the risk to nearby individuals from exposure to the radon emissions from mine vents, in some cases, may be relatively high. The 1989 NESHAPS regulates radon emissions from underground uranium mines.

Top of page

Clean Water Act (CWA)

The Clean Water Act (CWA) provided EPA the authority to limit liquid discharges of TENORM into surface waters from mines or mills used for the production of uranium, radium, and vanadium. The Clean Water Act is implemented through the National Pollutant Discharge Elimination System. Specific NPDES regulations apply to Mines and Mills.

summary | full text Exit EPA Disclaimer

Top of page

National Pollutant Discharge Elimination System (NPDES)

The National Pollutant Discharge Elimination System (NPDES)requires all pollutant discharges to the waters of the United States to comply with certain pollutant discharge criteria. The CWA requires facilities that discharge wastewater to have a permit, which establishes pollution limits, and specifies monitoring and reporting requirements. EPA has the authority under the CWA (and other environmental laws) to regulate radioactive materials not specifically addressed under the Atomic Energy Act (e.g., TENORM).

Top of page

Mines and Mills

NPDES guidelines establish limits on the radionuclide content for active mine drainage and mill discharges. Mines and Mills that discharge must obtain a permit. They are also required to monitor twice each year for specific pollutants determined by the type of ore they mine or process. For example, iron mines must monitor for dissolved iron and uranium/radium/vanadium mines must measure dissolved radium.

Top of page

Safe Drinking Water Act (SDWA)

Under the authority of the Safe Drinking Water Act, EPA develops National Primary Drinking Water Regulations to control radiation, including TENORM, in community drinking water systems.

In recent years, the act has been amended to require actions to protect drinking water and its sources- rivers, lakes, reservoirs, springs, and ground water wells.

In December, 2000 after a review of its national primary drinking water regulations for radionuclides, EPA issued a revised rule. It retained the standards established in 1976 (effective in 1977) to maintain protection of the existing standards as required by the Safe Drinking Water Act. It also established a maximum contaminant level goal (MCLG) for ionizing radiation required by the Act, and established a 20 microprogram/liter standard for uranium.

summary | full text Exit EPA Disclaimer

Top of page


Recent studies have shown that water treatment systems may carry radionuclides from industrial facilities or from natural sources that become concentrated during the treatment process. Keeping this in perspective - there have been no identified cases in the U.S. in which radioactive materials in sewage systems have been a threat to the health and safety of workers or the public. Several federal agencies have developed a guidance document to assist sewage treatment facilities and its workers deal with radioactivity in sewage sludge and ash.

Top of page

Comprehensive Environmental Response, Compensation and Liability Act (CERCLA)

CERCLA, better known as Superfund, provides EPA the funds and the authority to clean up abandoned hazardous waste sites, which may be contaminated with TENORM. EPA has developed guidelines for cleaning up soils contaminated with TENORM radionuclides, including radium, uranium and thorium.

The National Contingency Plan (NCP), enacted in 1990, outlines the regulations applicable to CERCLA (40 CFR Part 300). CERCLA and the NCP require preliminary remediation (cleanup) goals at any site to be protective of human health and the environment. They must also take into account other federal or state environmental laws, information such as Department of Energy orders, and the level of cancer risk posed by the site.

CERCLA summary | full text Exit EPA Disclaimer

Top of page


Local Navigation

Radiation Home

Jump to main content.