Navajo UMTRA entered into Cooperative Agreement with the U.S. Department of Energy (DOE) to assist/participate in the remedial actions activities of four Navajo UMTRA sites pursuant to the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). These sites are located in Tuba City, AZ; Monument Valley, AZ; Mexican Hat, UT; and Shiprock, NM.
Navajo UMTRA provides oversight, monitoring and review of the remedial action work at these sites. BY 1994, all surface remediation which included disposal of residual radioactive materials and debris has been completed pursuant to US EPA cleanup standards and regulations. By 1999, subsurface remediation work commenced by completing site characterization, developing remedial action plans with conceptual models and designs, and monitoring ground water remediation activities at three sites: Mexican Hat site requires no further active ground water remediation.