[en] 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. Throughout the operating period, mill tailings were used in the city of Monticello for construction purposes including fill for open lands; backfill around water, sewer, and electrical lines; sub-base for driveways, sidewalks, and concrete slabs; backfill against basement foundations; and as sand mix in concrete, plaster, and mortar. 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. Approximately 100,000 cubic yards (135,000 tons) of contaminated construction debris and wind blown deposited contamination is estimated to be within the Vicinity Properties. 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