I was in for that one, and working Titan missile security in Arizona (best duty the USAF ever had BTW).
Little Rock Arkansas, 19 September 1980. The silo had an oxydizer (N2O4 - dinitrogen tetroxide) leak. Techs failled to install safety skirts under them while working on that, so when they dropped a wrench it bounced off the silo walls and missile until it ruptured a fuel (UDMH - unsymmetrical dimethylhydrazine) tank. Fuel and oxidyzer collected in opposite ends of the silo until they met and did their thing - ignited. Blew the 740 ton blast door off the top of the silo and the 4 ton warhead (the mighty 9 megaton yield Mark 6, equal to about 600 Hiroshima bombs) was found some distance away in a farmer's field. One dead and 21 injured.
IIRC, that was the biggest warhead we ever put on anything. Newer MIRV's (multiple [3 - 12] independently targeted reentry vehicles) are more accurate, so we use way smaller warheads now.
I've got some even better stories, but if I told 'em the MIB would come for me...