The Monticello Vicinity Properties site, also known as the Monticello Radiation Contaminated Properties, is a federally-owned abandoned vanadium and uranium mill area in the city of Monticello, San Juan County, Utah. Milling of vanadium and uranium occurred from 1944 to 1960. Currently, the site consists of a dismantled vanadium and uranium mill, and stabilized mill tailings piles. The Monticello Radiation Contaminated Properties were accepted into the Department of Energy's Surplus Facilities Management Program in 1980 for remedial action. The Vicinity Properties were formally included on the NPL in 1986 and, therefore, must comply with requirements of CERCLA. In October 1989 the Millsite itself was also listed on the NPL. DOE established an official list of Vicinity Properties designated for remedial action based on radiological surveys conducted from 1971 to 1984. As of March 1989, 91 properties had been identified to be included in the Monticello Vicinity Properties. Of these 91 properties, 53 remedial actions have been completed and 12 additional properties are slated for remedial action in 1989. The primary contaminants of concern in construction material and debris are thorium-230, radium-226, and radon-222 contained in the vanadium and uranium mill tailings.