8. A thermonuclear bomb was accidentally dropped by the U.S. Air Force on New Mexico
On May 22, 1957, a USAF B-36 aircraft was transporting a MK-17 thermonuclear bomb from Biggs Air Force Base, Texas, to Kirtland Air Force Base, New Mexico. At 11:50am, as the B-36 approached Kirtland AFB at an altitude of 1,700 feet, the weapon slipped from its secured moorings and destroyed the bomb bay doors. Despite being equipped with a parachute designed to slow its descent, the low altitude of the aircraft combined with a malfunctioned parachute failed to impede the bombs momentum. Furthermore the bomb had had its release-mechanism locking pin removed – as was standard procedure during take-off and landing to allow for quick jettisoning – and exploded on impact approximately 4.5 miles south of the Kirtland control tower and 0.3 miles west of Sandia Base.
Having been previously separated from the fissile core for transit per safety regulations, the resulting explosion was limited to only creating a crater 12 feet deep and 25 feet in diameter. Fragments and component debris was scattered as far away as one mile from the impact point, and radioactive contamination was detected at the crater lip amounting to 0.5 milliroentgen requiring a careful clean-up operation overseen by the Field Command Armed Forces Special Weapons Project.