were given to the newly formed Atomic Energy Commission. More than were sold or transferred between 1955 and 1975, although the area on which the Niagara Falls Storage Site is located remained in the possession of the U.S. government. Buildings and operations Building 401 Beginning in 1943, Building 401 was used as the powerhouse for the production of TNT, though operations lasted less than a year. Building 401 was renovated, and from 1953–59 and 1965–71, it was used as a Boron-10 isotope separation plant. The interior of Building 401 was gutted in 1971, and its hardware and instrumentation were disposed of. Building 401 was demolished in 2010. Concrete silo A concrete silo was erected within the east boundary of the LOOW, immediately next to Porter Center Road, which was publicly accessible. A fence with signs warning of "radioactive material" ran next to the road. In 1952, drums containing of highly-radioactive K-65 residues were loaded into the silo. The concrete silo was dismantled sometime after 1979. Interim waste containment structure Construction of the interim waste containment structure was completed in 1991, and is located entirely within the Niagara Falls Storage Site. The mound is used for the storage of radioactive waste and residues, and the grass-covered "interim cap" is designed to retard both rainwater infiltration and radon emission. All of the contaminated and radioactive materials stored at the former LOOW site—including thorium, uranium, and the world's largest concentration of radium-226—were placed into the structure. Rochester Burial Site In 1951, laboratory waste and animals that had been injected with plutonium during experiments at the University of Rochester were shipped to the LOOW site for burial. US Army operations The United States Army was given an parcel of land from the original LOOW property, located on the northeast boundary. Beginning in 1957 it housed 36 Nike surface-to-air missiles intended to protect the nearby Niagara Hydroelectric Power Project. The property is currently licensed to the New York Army National Guard, and is used as a weekend training site. US Air Force operations A parcel of land from the original LOOW property was given to the United States Air Force, on which they located an experimental rocket fuel plant called the Youngstown Test Annex Site. Private waste treatment facilities Hooker Chemical Company purchased a large portion of the original LOOW property from a private landowner in 1975 to use as a dump site. Waste Management,