Personnel from Sandia National Laboratories in New Mexico installed four permeable reactive barriers PRBs at the Durango, Colorado, Uranium Mill Tailings Radiation Control Act Title I site in October 1995. These PRBs are managed by LM. Foamed zero-valent (ZVI) iron bricks produced by Cercona of America, steel wool, and granular iron have been used as reactive media to remove ammonium, arsenic, cadmium, chromium, manganese, molybdenum, nitrate, radium-226, selenium, uranium, vanadium, and zinc contamination from leachate exiting the uranium mill tailings disposal cell. After passing through the ZVI, the leachate contaminant levels meet the regulatory standards. The performance of the PRBs is described in Performance of a Permeable Reactive Barrier Using Granular Zero-Valent Iron: FY 2004 Annual Report, Durango, Colorado, Disposal Site.