Since 1950, says Zaria Gorvett on BBC Future, the American military has recorded at least 32 so-called “broken arrow” accidents – where nuclear weapons were “dropped or jettisoned” by mistake, usually in plane crashes. Thankfully, the bombs are fitted with safety features to prevent an inadvertent thermonuclear explosion. But there have been some close calls. When a B-52 bomber broke up over North Carolina in 1961, dropping two nukes, three of the four safeguards on one of the devices failed. Catastrophe was averted, the Secretary of Defence later wrote, by “literally the failure of two wires to cross”.
Incredibly, three American nuclear missiles “have gone missing altogether”. One was attached to a jet that fell off the side of an aircraft carrier into the Philippine Sea. Another was dropped somewhere off the coast of Georgia after a mid-air collision. The third was lost in Greenland after a cabin fire forced the crew to eject, “leaving the plane to crash with its nuclear payload on board”.
Other countries have lost nukes too, of course. When a Soviet nuclear-armed submarine sank in the Pacific Ocean in 1968, the US found out and mounted a “secret attempt” to retrieve it. The CIA got the aviation billionaire Howard Hughes to pretend to develop an interest in deep sea mining. His firm constructed a purpose-built ship – the Hughes Glomar Explorer – with a “giant claw” to grab the sub from the sea floor and bring it to the surface. Alas, the vessel broke up during the recovery operation, and the nukes fell back to the bottom of the ocean. That’s the official story, at least.