Canonsburg Mill

Location: The Canonsburg mill site is located in the Borough of Canonsburg, Washington County, Pennsylvania.

Background: From 1911 to 1922, the Standard Chemical Company operated a radium extraction plant on a 19-acre site in Canonsburg. Between 1930-1942, uranium and radium salts were extracted at the Canonsburg plant from residues and uranium ore. From 1942 to 1957, Vitro Manufacturing Company (later the Vitro Corporation of America) operated a mill at the site to recover uranium and rare metals from various ores and onsite residues, government-owned uranium ore, process concentrates, and scrap materials. The uranium concentrates produced by Vitro were sold to the U.S. Government. The waste products that accumulated at the site over its long history include residues generated by the incomplete extraction of radium, uranium, and other metals during processing of ore, byproduct chemical precipitates such as iron oxides and gypsum, process solutions, raw unprocessed ore materials, and uranium mill tailings. The total quantity of uranium/radium-bearing materials that were processed at the Canonsburg site during the periods of operation is not readily calculated based on the total radioactive waste volumes reported in the literature for the Canonsburg and Burrell sites. The uranium mill tailings were initially stored in uncovered piles, and the tailings material became dispersed by wind and water erosion. Some tailings material were also removed from the mill site for use as fill in local and regional construction projects. In 1956 and 1957, about 11,600 tons of mill tailings from the Canonsburg site were relocated to a railroad property near Blairsville in Burrell Township, Pennsylvania. After the Vitro uranium mill was closed down in 1957, the site was used until about 1966 as a storage facility under a contract issued by the Atomic Energy Commission. The land was purchased in 1967 by private interests and eventually became the Canon Industrial Park, a commercial park for light industrial use.