Site Plain EPA Superfund sites near you, in plain language

EPA Superfund site

LUKACHUKAI MOUNTAINS MINING DISTRICT

Human exposure is NOT currently under control

  • AZ
  • EPA ID NNN000920223
  • EPA exposure status as of October 11, 2026
No published boundary EPA has not published a boundary for this site, so Site Plain cannot calculate how far an address is from it, and it does not appear in address lookup results. EPA's site profile shows where it is: View EPA site profile

Data limitations: Proximity to a Superfund site boundary does not mean your property is contaminated. EPA site boundaries show the area designated for cleanup, not the full extent of contamination. Groundwater plumes can extend beyond site boundaries. This tool shows publicly available EPA federal data. It is not affiliated with or endorsed by EPA, and is not a substitute for a professional environmental assessment.

About this site's exposure pathways

As of October 2025, the Lukachukai Mountains Mining District site is considered “Current Human Exposure Not Under Control” (HENC). The site consists of 88 mine claims within the LMMD site that are not included in settlements or enforcement agreements. The mines and waste piles include direct exposure and potential migration to air, surface water, and groundwater of uranium, vanadium, radium-226, and other metals. Initial remedial investigation and removal site evaluation sampling results indicate ongoing direct exposure pathways and evidence of migration to surface water bodies downstream of the mines. These exposure and migration pathways are considered unacceptable based on EPA risk-based criteria because risk assessments typically require cleanup to background levels for radium-226 for sheep camp, and easy and difficult access open space exposure scenarios.
Currently, the site is undergoing a remedial investigation which will be finalized in spring or summer 2029. Some mines are undergoing non-time critical removal actions to address ongoing exposures and releases. If you are impacted by risks inherent at this site, you may reduce your exposure by avoiding the mine areas or limiting your time spent on or near the mines. EPA, in cooperation with Navajo Nation EPA, anticipates that human exposure will be under control by summer 2040 because the remedial investigation, proposed plan, and record of decision must first be completed.
In addition, EPA is currently working to limit access the mines and post warning signs surrounding the mines to help prevent inadvertent exposure.

Was this information helpful?