On this day in history, the U.S. the US Air Force narrowly averted detonating an atom bomb over North Carolina that would have been 250 times more powerful than the one that devastated Hiroshima. A B-52 Stratofortress plane carrying two Mark 39 hydrogen bombs broke up in mid-air, dropping its nuclear payload in the process. The captain ordered the crew to eject, which they did at 9,000 feet. Five men successfully ejected or bailed out of the aircraft and landed safely. Another ejected but did not survive the landing, and two died in the crash.
The hydrogen bomb that dropped from the plane had six safety mechanisms to prevent its accidental detonation, and five of the six failed. Only one low-voltage switch prevented the activation of the bomb, which carried a payload of 4 megatons – the equivalent of 4 million tons of TNT explosive. When the bomb hit the ground, a firing signal was sent to the nuclear core of the device, and it was only the failure of that final, highly vulnerable switch that averted calamity.
Had the bomb detonated, it would have pulverized a portion of North Carolina and, given strong northerly winds, could have blanketed East Coast cities (including New York, Baltimore, and Washington, DC) in lethal fallout.
This was just one of at least 700 “significant” accidents and incidents involving 1,250 nuclear weapons were recorded between 1950 and 1968 alone.
You can read about these and other near misses in Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of Safety by Eric Schlosser.