The document, obtained by the investigative journalist Eric Schlosser under the Freedom of Information Act, gives the first conclusive evidence that the US was narrowly spared a disaster of monumental proportions when two Mark 39 hydrogen bombs were accidentally dropped over Goldsboro, North Carolina on 23 January 1961. The bombs fell to earth after a B-52 bomber broke up in mid-air, and one of the devices behaved precisely as a nuclear weapon was designed to behave in warfare: its parachute opened, its trigger mechanisms engaged, and only one low-voltage switch prevented untold carnage.
Each bomb carried a payload of 4 megatons – the equivalent of 4 million tons of TNT explosive. Had the device detonated, lethal fallout could have been deposited over Washington, Baltimore, Philadelphia and as far north as New York city – putting millions of lives at risk.
"The US government has consistently tried to withhold information from the American people in order to prevent questions being asked about our nuclear weapons policy," he said. "We were told there was no possibility of these weapons accidentally detonating, yet here's one that very nearly did."