US nearly detonated atomic bomb over North Carolina in 1961

But most of the danger that human beings faced from nuclear weapons after the destruction of Hiroshima and Nagasaki had to do with inadvertence—with bombs dropped by mistake, bombers catching on fire or crashing, missiles exploding, and computers miscalculating and people jumping to the wrong conclusion. On most days, the probability of a nuclear explosion happening by accident was far greater than the probability that someone would deliberately start a war..........

A study run by Sandia National Laboratories, which oversees the production and security of American nuclear-weapons systems, discovered that between 1950 and 1968 at least twelve hundred nuclear weapons had been involved in “significant” accidents. Even bombs that worked didn’t work quite as planned. In Little Boy, the bomb dropped on Hiroshima on August 6, 1945, only 1.38 per cent of the nuclear core, just 0.7 grams of uranium, fissioned (although the bomb killed eighty thousand people). The bomb dropped on Nagasaki, three days later, was a mile off target (and killed forty thousand people). A test of the hydrogen bomb in the Bikini atoll, in 1954, produced a yield of fifteen megatons, three times as great as scientists had predicted, and spread lethal radioactive fallout over hundreds of square miles in the Pacific, some of it affecting American observers miles away from the blast site.

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