Qualla: Church Rock Uranium Mill Spill

Church Rock Uranium Mill Spill: Introduction

Wed, 28 Jan 2026 00:00:00 GMT

Photo credit Mark Purcell, EPA, USA, Public domain. Four months after Three Mile Island became a household name, a far larger release of radioactive material occurred in the remote desert of western New Mexico. Almost nobody heard about it. At 5:30 in the morning on July 16, 1979, a crack in the dam wall of United Nuclear Corporation's uranium mill tailings pond near Church Rock split wide open. Solid radioactive waste and acidic tailings solution poured into Pipeline Arroyo, a tributary of the Puerco River, and flowed downstream through Gallup, New Mexico and onward into Navajo County, Arizona. It was the largest release of radioactive material in United States history. The contaminated water backed up sewers, poisoned aquifers, and left stagnant, radioactive pools along the riverbanks where Navajo children had recently waded.

Image: Mark Purcell, EPA, USA | Public domain

Church Rock Uranium Mill Spill: A Dam Built to Fail

Wed, 28 Jan 2026 00:00:00 GMT

Photo credit Joseph D. Kane, John D. Nelson, Public domain. The United Nuclear Corporation mill operated from June 1977 to May 1982 on privately owned land northeast of Gallup, bordered on two sides by Navajo Nation Tribal Trust lands. The mill processed uranium ore into an acidic slurry of ground waste rock and fluid, pumped into holding...

Image: Joseph D. Kane, John D. Nelson | Public domain

Church Rock Uranium Mill Spill: Poison Flowing Downstream

Wed, 28 Jan 2026 00:00:00 GMT

Photo credit Joseph D. Kane, John D. Nelson, Public domain. The contaminated water traveled downstream through Gallup and reached as far as Navajo County, Arizona. As the highly acidic spill moved along the river, alkaline soils partially neutralized the acid, but yellow salt crystals containing metals and radionuclides precipitated onto ...

Image: Joseph D. Kane, John D. Nelson | Public domain

Church Rock Uranium Mill Spill: A Response That Never Came

Wed, 28 Jan 2026 00:00:00 GMT

Photo credit Joseph D. Kane and John D. Nelson, Public domain. The states of Arizona and New Mexico failed to immediately warn their residents. United Nuclear Corporation employees were dispatched to notify Navajo-speaking communities downstream, but not until days after the breach. The Navajo Nation asked New Mexico Governor Bruce King to r...

Image: Joseph D. Kane and John D. Nelson | Public domain

Church Rock Uranium Mill Spill: Studying Cattle, Ignoring People

Wed, 28 Jan 2026 00:00:00 GMT

Photo credit Joseph D. Kane, John D. Nelson, Public domain. The human cost received remarkably little attention. A few Navajo children were sent to Los Alamos to be checked for radiation exposure, but no long-term health monitoring was ever established. A local writer observed that the Indian Health Service spent more effort studying live...

Image: Joseph D. Kane, John D. Nelson | Public domain

Church Rock Uranium Mill Spill: The Longest Cleanup

Wed, 28 Jan 2026 00:00:00 GMT

Photo credit Joseph D. Kane, John D. Nelson, Public domain. Initial cleanup efforts were almost comically inadequate. United Nuclear sent small crews with shovels and drums, retrieving an estimated one percent of the solid waste spilled over three months. The Navajo Nation again appealed to the governor to declare the site a federal disas...

Image: Joseph D. Kane, John D. Nelson | Public domain