The uranium that fed American weapons production came disproportionately out of New Mexico ground, and much of what the industry left behind is still here. This data brief assembles the published record of heavy metal and uranium contamination across the Southwest, from the mines and mills of the Grants belt and the Navajo Nation to the weapons laboratories, and ends with a research idea for reading the history of that contamination in museum collections. Values labeled published come from the agency documents and peer-reviewed studies in the references, including work from Jose Cerrato’s group at UNM. Anything marked computed or constructed is arithmetic or framing of mine, not a claim the sources make. Photographs are public-domain federal images.
Weapons demand built the industry (published)
The first atomic bomb was designed at Los Alamos and detonated at the Trinity Site in the Tularosa Basin on July 16, 1945. The uranium procurement program that followed turned northwestern New Mexico into the country’s dominant producer. The state yielded 348 million pounds of U3O8 between 1948 and 2002, 37.5% of all US production, and the Grants district out-produced every other district in the country from 1951 to 1980. The federal Atomic Energy Commission was the industry’s original customer, and commercial reactor fuel sustained it later. On the Navajo Nation, nearly 30 million tons of ore came out of the ground between 1944 and 1986 under leases with the tribe.
The mines never closed properly (published)
EPA counts 523 abandoned uranium mines on and near the Navajo Nation. Enforcement agreements now valued at over $1.7 billion fund assessment or cleanup at 230 of them, which leaves more than half without committed funds. Southeast of the Navajo Nation, at Laguna Pueblo, the Anaconda company leased 7,868 acres in 1953 and ran the Jackpile-Paguate mine for thirty years, moving about 400 million tons of rock to produce 25 million tons of ore from what was for much of its life one of the world’s largest open-pit uranium mines. Three Laguna villages with about 1,800 residents sit at its edge. Reclamation was declared complete in 1995, EPA later concluded it was not, and the site is now a Superfund site at the start of a cleanup expected to last decades.
Cerrato’s group at UNM has quantified what not complete means in the water. Along the Rio Paguate, which flows through the Jackpile site, mine waste sediments carry 320 to 9,200 mg/kg uranium, and surface water adjacent to the mine reaches 772 micrograms per liter, twenty-six times the EPA drinking water standard of 30. Concentrations peak during monsoon season, and an organic-rich wetland 4.5 km downstream accumulates the uranium the river carries.
The water carries it (published)
On July 16, 1979, the tailings dam at United Nuclear’s Church Rock mill breached and sent about 94 million gallons of acidic tailings solution and more than 1,100 tons of solid tailings down the Puerco River, roughly 46 curies of radioactivity that traveled about 80 miles into Arizona. It remains the largest single release of radioactive material into the US environment, and it happened four months after Three Mile Island with a small fraction of the attention. About 1,700 mostly Navajo residents lost their water supply. As of 2016 EPA still classified groundwater migration at the site as not under control.
The chronic exposure is quieter than the accident. Roughly 30% of Navajo Nation households lack access to a public water system and haul water from unregulated sources. In the largest compilation of those sources, 15.1% of 464 tested wells and springs exceeded the arsenic standard and 12.8% exceeded the uranium standard, with sources within 6.4 km of an abandoned mine more likely to exceed both.
The research campus legacy (published)
The weapons complex itself left plumes as well as fallout. At Los Alamos, cooling-tower water treated with potassium dichromate was flushed into Sandia Canyon from 1956 to 1972, and the hexavalent chromium now sits in the regional aquifer 900 to 1,000 feet down, in a plume about a mile long, half a mile wide, and 100 feet thick as defined by the 50 ppb state standard, roughly 500 feet from the boundary with the Pueblo de San Ildefonso. Downwind of Trinity, the Tularosa Basin communities waited eighty years for recognition. The Radiation Exposure Compensation Act, renewed and expanded in 2025, made New Mexico downwinders and post-1971 uranium miners eligible for federal compensation for the first time, with applications open through December 31, 2027.
Reading the record in bone (my own, framing constructed)
Nearly all of the numbers above come from samples collected after the fact, monitoring that began decades after the peak releases. That gap is the motivation for an early-stage NSF proposal concept I am developing with Jose Cerrato at UNM, to be run through the Center for Stable Isotopes. Museum collections hold fish collected from Four Corners rivers continuously through the production era, and bone archives the trace metals a fish took up from its water. Stable and radiogenic isotope measurements on dated museum specimens could reconstruct the temporal progression of uranium-mining contaminants through these watersheds. The concept is at the idea stage, and I am stating it here as such rather than as a result.
References and data
- US EPA. Abandoned uranium mines cleanup, Navajo Nation. Program page
- NM Bureau of Geology and Mineral Resources. Uranium resources in New Mexico. Production tables
- Blake J.M. et al., Cerrato J.M. (2017) Uranium mobility and accumulation along the Rio Paguate, Jackpile Mine in Laguna Pueblo, NM. Environ. Sci. Process. Impacts 19, 605–621. Article
- Hoover J., Gonzales M., Shuey C., Barney Y., Lewis J. (2017) Elevated arsenic and uranium concentrations in unregulated water sources on the Navajo Nation. Exposure and Health 9, 113–124. Article
- Church Rock uranium mill spill. Overview with primary citations, NM In Depth retrospective
- High Country News (2022) Forty years after its closure, the Jackpile Mine’s toxic legacy continues. Feature
- US DOE, Los Alamos hexavalent chromium plume fact sheet. PDF
- Source New Mexico (2026) on the 2025 RECA expansion. Brief