There was a story going around in the late 70's at a Vulcan servicing unit, of a tradesman sat in a Vulcan fuel tank, reading a book by torchlight.
Apparently the X ray guys turned up & did their business, oblivious of the tradesman in said tank. The story went that the X ray guys were horrified when looking at the plates, to see the ghostly outline of a skeleton sat in the tank.
I somehow doubt the veracity of the story, but it was popular at the time.