Weldon Spring became the country's largest explosives plant during World War II and later a uranium-processing facility for Cold War nuclear weapons, followed by long-term cleanup and stewardship efforts. In 1940, just before the United States entered World War II, the U.S. government acquired 17,000 acres in this area under a state of emergency, moved more than 500 people from Howell, Hamburg, and Toonerville, and dismantled those villages. The Army then built Weldon Spring Ordnance Works, which produced more than 710 million pounds of TNT and more than 31 million pounds of DNT for the war effort. During the Cold War, the Atomic Energy Commission created the Weldon Spring Uranium Feed Materials Plant, operated by Mallinckrodt Chemical Works of St. Louis, and from 1957 to 1966 the plant converted uranium ore concentrate, or yellowcake, into pure uranium metal for shipment to other nuclear weapons and fuel sites, while waste was stored in four basins and a nearby quarry. Beginning in 1986, the U.S. Department of Energy carried out a 16-year cleanup costing almost one billion dollars, encapsulating about 1.5 million cubic yards of radioactive and chemical waste in a 45-acre disposal cell, including waste from the basins and quarry, 6,130 steel drums, contaminated soils and materials, and debris from 44 removed buildings; the cell received its final load in July 2001. The site now includes a visitor center, hiking and bicycling trail, and prairie restoration area. Separately, the U.S. Department of Defense spent about 40 million dollars cleaning the former ordnance works by removing and incinerating over 50,000 cubic yards of contaminated soil and about 83,000 feet of wooden pipeline tainted with TNT, DNT, and lead, after which the area was returned to Army Reserve use as a training area. Long-term stewardship is intended to protect human health, public welfare, and the environment through monitoring, inspection, maintenance, and information sharing, while preserving knowledge of the disposal cell and its contents for future generations; the cell is designed to last a thousand years, withstand severe precipitation and earthquakes, and contain uranium waste with a half-life of 4.5 billion years.
