Hugh Pickens writes "A BBC investigation has found that in 1968 the US abandoned a nuclear weapon beneath the ice in northern Greenland after a nuclear-armed B52 crashed on the ice a few miles from Thule Air Base. The Stratofortress disintegrated on impact with the sea ice and parts of it began to melt through to the fjord below. The high explosives surrounding the four nuclear weapons on board detonated without setting off the nuclear devices, which had not been armed by the crew. The Pentagon maintained that all four weapons had been 'destroyed' and while technically true, investigators piecing together fragments from the crash could only account for three of the weapons. Investigators found that 'something melted through ice such as burning primary or secondary.' A subsequent search by a US submarine was beset by technical problems and, as winter encroached and the ice began to freeze over, the search was abandoned. 'There was disappointment in what you might call a failure to return all of the components,' said a former nuclear weapons designer at the Los Alamos nuclear laboratory. 'It would be very difficult for anyone else to recover classified pieces if we couldn't find them.'"