The 2007 United States Air Force nuclear weapons incident occurred at Minot Air Force Base and Barksdale Air Force Base on 29–30 August 2007. Six AGM-129 ACM cruise missiles, each loaded with a W80-1 variable yield nuclear warhead, were mistakenly loaded on a United States Air Force (USAF) B-52H heavy bomber at Minot and transported to Barksdale. The nuclear warheads in the missiles were supposed to have been removed before taking the missiles from their storage bunker. The missiles with the nuclear warheads were not reported missing and remained mounted to the aircraft at both Minot and Barksdale for a period of 36 hours. During this period, the warheads were not protected by the various mandatory security precautions required for nuclear weapons.