The site includes the disposal area, the abandoned Uranium Feed Materials Plant, various smaller properties, and the former limestone quarry located 4 miles from the plant. Primary contaminants of concern at the Chemical Plant and surrounding soil include uranium, thorium, radium, and their radioactive decay products. The quarry contains materials contaminated with TNT and DNT residues, as well as uranium, thorium, and radium residues and contaminated materials and equipment. The quarry is located from the St. Charles County well field, which is used as a drinking water source for approximately 70,000 people. Weldon Spring Former Army Ordnance Works site On July 14, 1989, the United States Environmental Protection Agency proposed adding the Weldon Spring Ordnance Works to the National Priorities List. The site was officially listed on February 21, 1990. Contaminated areas are spread throughout the site, with the greatest concentration in the Training Area. Areas of concern include seven unlined lagoons where TNT wastewater was stored, TNT production lines, two DNT production lines, drainage ditches below TNT production lines, and eight areas where explosive wastes were burned. The primary contaminants of concern at the site are TNT, DNT, and lead. These contaminants have been identified in soil at several areas on the site, and TNT was detected in 1987 in surface water downstream of the lagoons. Portions of the August A. Busch Memorial Conservation Area are within the Weldon Spring Former Army Ordnance Works site. See also List of Superfund sites in Missouri References United States Army arsenals Manufacturing plants in the United States Buildings and structures in St. Charles County, Missouri Nuclear weapons infrastructure of the United States Military Superfund sites Military installations in Missouri United States Army arsenals during World War II Superfund sites in Missouri