Abstract: Employee #1 and a coworker were pressure-testing the seals around the shaft on a large Solar Turbines, Inc., compressor, model C505. Employee #1 had installed 1-ton temporary cover plates over the inlet and outlet ports of the compressor, using only 7 bolts on each plate instead of the 20 bolts each had holes for, and threading the bolts only 1/2 in. to 1 in. instead of 4 in. When the pressure reached over 100 psi, one pressure plate blew off, flying about 50 ft. Employee #1 was decapitated. The coworker sustained multiple hand fractures, was partially deafened, and has vision problems. Employee #2, who was setting up another unit for testing about 15 ft away, suffered shoulder bruises and lacerations. The compressor was located just outside a garage-like test cell where Employee #2 worked.