On 4 August 1953, the Department of the Army reduced OCS from eight to three programs: Infantry, Artillery, and Engineer, finally closing Engineer OCS in July 1954, leaving only the Infantry and Field Artillery schools open. With the onset of the Vietnam War, however, the OCS program was again expanded with officer candidates undergoing a grueling 23-week program of instruction with an extremely high attrition rate which was designed to prepare young officers to be platoon leaders in a demanding Vietnam jungle environment. In September 1965, Engineer OCS reopened at Fort Belvoir, Virginia, and before closing for good in 1971, over 10,000 Engineer Officers had been commissioned.