My grandparents always talk about the Port Chicago explosion during WWII. It broke the front plate view window of their house in Concord about six miles away as the crow flies, even though the window was facing AWAY from the blast (at a bit of an angle, though). My great-uncle and -aunt lived in Port Chicago itself and had big pieces of metal debris all over their yard. Estimates are about 6800 TONS of explosives went off.

Some conspiracy types have postulated that one of the ships destroyed in the explosion was carrying what would have been the first nuke dropped on Japan. They cite the mushroom cloud as evidence. Clueless, eh?

Joe, at what range would a 350,000 pound explosion be considered to be "entertainingly close" I wonder?

"Entertainingly close" can be calculated from the data on this page: http://www.boomershoot.org/general/Effects.htm

Go to the "fatal injuries" section. Set P (probability of a fatal injury) to the risk you are willing to accept (0.01 for 1 chance out of a hundred) and then solve for "D", the distance in feet.