Colorado uranium mill tailings sites

Cleanup of Colorado's former uranium mill sites was authorized by the Uranium Mill Tailings Remedial Action (UMTRA) program, and the Colorado Department of Public Health and Environment (CDPHE) says that cleanup has been completed. Its work now is mostly what it calls post-UMTRA issues: uranium mill tailings newly discovered by private citizens, utility companies or local governments.

In a Phase I ESA

ASTM E1527-21 does not name uranium mill tailings records among its standard record sources. They bear on one question: whether uranium mill tailings were used on the property as a building material.

• Tailings went into buildings. CDPHE says that before their hazards were recognized and regulated, uranium mill tailings were used as a building material in Mesa County, commonly in foundations, mortar, driveways, soil and other places on a property. Many properties were cleaned up in the 1970s, 1980s and 1990s, but CDPHE says tailings can still be found at numerous locations throughout the county.
• Nine communities. CDPHE lists Durango, Grand Junction, Fruita, Palisade, Gunnison, Maybell, Naturita, Rifle and Slick Rock as the western Colorado communities where tailings were cleaned up. It says 15 million cubic yards were removed to controlled disposal sites from the nine mill sites and approximately 5,000 other contaminated properties, and that final authorization for surface cleanup ended in 1998.
• A survey may be on file. CDPHE says gamma radiation surveys are the best way to locate tailings, that many properties in Mesa County were surveyed in the past and the results may be on file, and that a new survey can be requested if they are not.
• A building permit is the trigger. CDPHE says no action is required unless a property owner is applying for a building permit, though it recommends removal when possible. The cost of removal is the owner's, and tailings can be disposed of in Grand Junction free of charge. For a property slated for construction, ask for the survey before the permit stage.
• The online material is not the official answer. CDPHE's page carries a disclaimer: the materials on it are for convenience and information only, and are not to be relied on in place of an official mill tailings report or gamma radiation survey.

CDPHE says the disposal cells will continue to be monitored and maintained by the U.S. Department of Energy, whose Office of Legacy Management is responsible for long-term maintenance and records management. CDPHE also publishes a uranium mill tailings management plan, which it describes as guidance for managing tailings encountered during construction, and a separate plan for the Durango area.

Where to look a site up

CDPHE's Uranium mill tailings sites page links:

• a statewide interactive map of UMTRA sites;
• a data view it titles UMTRA Website Reports;
• a form to request a gamma radiation survey, a mill tailings report, or a gamma radiation re-survey. The link is marked "for realtors".

Getting the file

The request form on the Uranium mill tailings sites page is the route to an official mill tailings report or survey for one property. CDPHE's FAQ says its UMTRA Program staff are in Grand Junction. For other division records, requests go through the form on the records review page or to cdphe_cora_hmwmd@state.co.us.

Sources

Colorado Department of Public Health and Environment pages, read October 7, 2026, no modified date shown:

• Uranium mill tailings sites
• Uranium mill tailings background
• Uranium mill tailings FAQ
• Hazardous Materials and Waste Management Division records review