- Waste from abandoned uranium mines will be relocated.
- New repository will sit one mile from the Little Colorado River.
- Cleanup design expected to begin in 2026.
Tuesday, September 30, 2025 — The U.S. Environmental Protection Agency (EPA) announced on September 25, 2025, that it has approved a removal action to safeguard the Little Colorado River in northern Arizona from uranium contamination. The project involves relocating waste from two abandoned uranium mines and part of a third into a newly constructed on-site repository. The repository will be located about one mile from the river, reducing the risk of contaminants entering the watershed.
The Section 9 Lease Mine Site, which sits in Coconino County near the Navajo Nation and the Cameron Mining District, has long posed a threat due to abandoned mining waste left near the river. EPA officials coordinated with the Arizona Department of Environmental Quality (ADEQ) and consulted with local stakeholders to determine the best way to protect the river and its surrounding lands.
Voices from the Cleanup Effort.
“September 25’s announcement marks major progress on the cleanup of abandoned uranium mines in the region,” said Mike Montgomery, EPA Pacific Southwest Region Superfund Division Director
. He added that moving the waste away from the river will reduce uranium contamination risks for Navajo communities and the broader watershed.
Arizona Department of Environmental Quality Director Karen Peters also expressed support, stating that she looked forward to continued collaboration with the EPA in protecting Arizona residents.
Cleanup Timeline and Restoration Plans.
The removal design process is expected to start in 2026. Once underway, the EPA will relocate the uranium waste into the secure repository, ensuring protection of both human health and the environment from radiation linked to past mining. Following removal, the mine sites will be restored to more natural conditions, helping preserve critical habitats and cultural resources along the river.
In addition to addressing the immediate problem, EPA officials noted that the new repository could also serve as a regional site for waste from other abandoned uranium mines in the Cameron Mining District. This could streamline future cleanup efforts and reduce costs.
Information about the EPA’s efforts in cleaning up abandoned uranium mines on the Navajo Nation is published on the EPA’s website.
Image via the EPA.
FAQ
What are PFAS or “forever chemicals”?
PFAS are a separate category of pollutants often in the news, but in this case, the EPA announcement dealt with uranium contamination. Uranium mine waste releases radioactive particles, while PFAS are industrial compounds known for persisting in the environment.
Why is uranium waste a concern near rivers?
Abandoned uranium mines can release radioactive material into soil and waterways. If left in place, contaminants may spread into rivers and groundwater, threatening ecosystems and human health.
Where is the Section 9 Lease Mine Site located?
It is in Coconino County, Arizona, near the Little Colorado River and close to the Navajo Nation in the Cameron Mining District.
When will cleanup begin?
The removal design process is expected to start in 2026. Actual relocation of the waste will follow, depending on design and construction progress.
Will the new repository store waste from other mines?
Yes, the EPA indicated the repository may also be used for waste from other abandoned uranium mines in the region, helping streamline cleanup across the district.
