Weldon Spring Ordnance Works Weldon Spring Ordnance Works ( WSOW ) was a U . S . Government - owned , contractor - operated ( GOCO ) facility in St . Charles County , Missouri , 55 km west of St . Louis . The site was originally operated by the Atlas Powder Company during World War II from 1941 to 1945 to produce explosive s . The Atomic Energy Commission acquired part of the property in 1955 , and Mallinckrodt , Inc . processed uranium ore from 1957 to 1966 under contract . The site has been divided into several parcels , and ownership has transferred over the years . Two portions of the original WSOW property are now Superfund sites that require substantial cleanup efforts . The environmental remediation of the WSOW site is currently designated as a major project of the Defense Environmental Restoration Program of the United States Department of Defense . Part of the original property is still used by the Army Reserve as the Weldon Spring Training Area . The site was purchased in 1941 , totaling of largely rural land . The towns of Hamburg , Howell , and Toonerville and around 700 citizens of the area were displaced beginning in 1940 and ending the following year . From 1941 to 1945 , the Atlas Powder Company manufactured trinitrotoluene ( TNT ) and dinitrotoluene ( DNT ) at the site . Four TNT and two DNT production lines were situated on what was to be the Chemical Plant . These operations resulted in nitroaromatic contamination of soil , sediments , and some off - site springs . After World War II , over were transferred to the State of Missouri , including the August A . Busch Memorial Conservation Area . Additional land was transferred to the University of Missouri , St . Charles County , and the Francis Howell School District . Much of the land that was transferred to the University of Missouri has become the Weldon Spring Conservation Area . Weldon Spring Chemical Plant . Following a considerable amount of environmental remediation of the facility by the U . S . Army and the Atlas Powder Company , of the former ordnance works were transferred to the United States Atomic Energy Commission ( AEC ) in 1955 for construction of the Weldon Spring Uranium Feed Materials Plant , now referred to as the Weldon Spring Chemical Plant . Mallinckrodt , Inc . operated the plant from 1957 to 1966 under a contract with the AEC . An additional were transferred to the AEC in 1964 . The plant converted processed uranium ore concentrates to uranium tetrafluoride , uranium trioxide , intermediate compounds , and uranium metal . A small amount of thorium was also processed . Wastes generated during these operations were stored in four raffinate pits located on the plant property . Uranium processing operations resulted in radiological contamination of the area . Uranium processing operations ceased in 1966 , and on December 31 , 1967 , the AEC returned the facility to the Army for use as a defoliant production plant . The defoliant project was canceled before any process equipment was installed , and the Army transferred of land encompassing the raffinate pits back to the AEC while retaining the Chemical Plant . The AEC , and subsequently the United States Department of Energy ( DOE ) , managed the site , including the Army - owned Chemical Plant , under caretaker status from 1968 through 1985 . In 1984 , the Army repaired several of the buildings at the Chemical Plant , decontaminated some of the floors , walls , and ceilings , and isolated some equipment . In 1985 , the Army transferred full custody of the Chemical Plant to the United States Department of Energy ( DOE ) , at which time the DOE designated control and decontamination of the Chemical Plant , raffinate pits , and Quarry as a major project . The DOE legacy management web site has additional documentation on the status of the site . Weldon Spring Quarry . The Weldon Spring Quarry was mined for limestone aggregate used in construction of the ordnance works . The Army also used the quarry for burning wastes from explosives manufacturing and disposal of TNT - contaminated rubble during operation of the ordnance works . These activities resulted in contamination of the soil and groundwater at the quarry . In 1958 , the Army transferred the Weldon Spring Quarry to the Atomic Energy Commission , who used it from 1959 to 1966 as a disposal area for uranium , thorium , and radium residues from the Chemical Plant ( both drummed and uncontained ) and for disposal of contaminated building rubble , process equipment , and soils from demolition of a uranium processing facility in St . Louis . Radiological contamination occurred in the same locations as the nitroaromatic contamination . Weldon Spring Training Area . By 1959 , with the majority of the site already transferred out of government hands , was redeveloped as for the U . S . Army Reserve as the Weldon Spring Training Area . Superfund sites . Weldon Spring Quarry / Plant / Pits ( USDOE / Army ) site . On October 15 , 1984 , the United States Environmental Protection Agency proposed listing the portions of the Weldon Spring area contaminated with radioactive waste on the National Priorities List . The site was finally listed on July 22 , 1987 . The Weldon Spring Quarry / Plant / Pits ( USDOE / Army ) site covers and is located between the Missouri and Mississippi Rivers . 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 .