The Rocky Mountain Arsenal (RMA) was built in 1942 to manufacture chemical weapons. A portion of the site was leased to private industry in 1946 for petroleum production and agricultural and industrial chemical manufacturing. When the American chemical weapons program was shut down after the Vietnam War, the RMA served as a site for dismantling and disposing of these weapons. The Shell Oil Company also used a portion of the site in the 1980s to produce pesticides. The RMA was closed in 1985, and in 1987 environmental testing revealed that the site was extremely polluted. The RMA was listed on the National Priorities List, a list of hazardous waste sites in the United States eligible for long-term remedial action (cleanup) financed under the federal Superfund program run by the Environmental Protection Agency.