Although the Air Force chose, based on the Bien Hoa and NKP tests, not to deploy the weapon to the two combat units in-theater, an inventory of the canisters was kept. By April 21, 1975, South Vietnam had largely been conquered by the People's Army of Vietnam (PAVN). Earlier in the month, a single CBU-55 had been flown to Bien Hoa. The senior US military officer in Vietnam, Major General Homer D. Smith, cleared the way for the Saigon government to use the weapon against the PAVN. An RVNAF C-130 transport plane circled Xuan Loc at , then dropped the bomb. The contents exploded in a fireball over a area. Experts estimated that 250 soldiers had been killed, primarily by the immediate depletion of oxygen rather than from burns. The CBU-55 was never used again in the war, and South Vietnam's government surrendered on April 30.