The Sunflower Army Ammunition Plant was originally known as the Sunflower Ordnance Works. Established in 1941 on 10,747 acres, it was the world's largest smokeless powder plant. Although owned by the U.S. government, the plant was operated by the Hercules Powder Company under a contract signed on May 11, 1942. Construction then began immediately and was followed by the first production of propellant 10 months later. During World War II, the Sunflower Ordnance Works produced more than 200 million pounds of propellants and employed as many as 12,067 people. Following the war, the plant was placed on partial standby. And in March 1947, the contract with Hercules Powder Company expired. When the plant was placed on complete standby in June 1948, the government took over maintenance and security. In 1951, the Sunflower Ordnance Works was brought out of standby due to the Korean War. Once again, on June 30, 1952, the operation of the plant was contracted out to Hercules. This time the plant produced more than 166 million pounds of propellants, with employment of up to 5,374. The plant then went into standby again in June 1960. The name of the plant was changed from the Sunflower Ordnance Works to Sunflower Army Ammunition Plant on August 1, 1963. Two years later, on August 20, 1965, the plant was reactivated to aid the Vietnam War by producing in excess of 145 million pounds of propellants before ceasing operations in June 1971. While operating during this time, the plant employed up to 4,065 people. In 1972, the plant was returned to standby status. A major facility modernization program was started in August 1967. The program included the construction, between 1975 and 1979, of a facility for the production of nitroguanidine. This facility was the first of its kind in North America and began production in 1984 and continued until 1992, when the plant was again placed on standby. Nitroguanidine is an essential component of triple-base gun propellant. In addition to being an oxidizer and energy carrier, it is loaded with hydrogen and this provides cooling in the gun tube which reduces the erosion rate of the tube metal so more rounds can be fired before refit. NQ was shipped out in fiberboard drums to another army facility where the triple-base is prepared, Alliant Techsystems won a contract on March 10, 1995 to market the use of the Sunflower Army Ammunition Plant facilities. Also in February 1995, the Environmental Protection Agency proposed that the site be placed on the National Priorities List, but it was never listed. Early in 1998, SFAAP was declared excess by the U.S. Army, and the General Services Administration began the process of selling the site. As of October 1, 2001, the Army changed to a maintenance contractor and reduced the number of buildings used to an office building, an environmental laboratory, the old guard headquarters as a records repository, and the guard shack at the main gate. The Sunflower Army Ammunition Plant rail system was operated under contract by Hercules, Inc. The system included 59 miles of track, with rails ranging in size from 85 to 100 pounds connecting with BNSF Railway, and the enginehouse was Building 501. Operations were conducted from Monday through Friday, 0800 to 1600 with a GE 80-ton locomotive numbered US Army 1662. Formerly assigned to Letterkenny Army Depot, PA, the locomotive went from Sunflower AAP to McAlester AAP, OK, where it was reported to being shipped to Senaca Army Depot, NY, in October 1999. When Seneca AD closed, the locomotive was sold to the Dominican Republic. All of the track at Sunflower AAP was pulled up following the plant's closure.
