Abstract: Employee #1, a shop foreman, and two coworkers were working in the production area of a small tool and manufacturing company. They were using compressed air to pressure test an aluminum dome assembly unit that was being manufactured for the Department of Defense. (The unit was approximately 20 in. in diameter; 7 in. high; and weighed approximately 10 lb.) It was secured to an aluminum base plate by 15 aluminum clips and 1-in.-long, 0.25-in. steel bolts, which were evenly spaced around the perimeter of the dome flange and inserted into threaded holes in the base plate. The base plate measured approximately 25 in. by 25 in. by 0.75 in. and weighed approximately 751 lb. The shop compressor supplied the compressed air. The line pressure was unknown; D.O.D. specifications required 75 psi. After introducing the compressed air into the unit, Employee #1 heard the hissing sound of escaping air. He leaned over the unit to run his hand around the outside perimeter and locate the air leak. At this point, 11 of the 15 clips holding the dome unit in place failed, and the dome unit exploded upward. The unit struck Employee #1 on the forehead and fractured his skull. He died several hours later in the hospital.