Fatality during hydrotest due to non removal of air

 Employee #1, a millwright, was standing near a 100 ft long by 5 ft diameter vacuum fat-splitter vessel that was undergoing a hydrostatic test. He was by the M-1 flange joint when the gasket experienced a catastrophic failure. Employee #1 was struck in the face by air and water released at the maximum allowable working pressure of 1,275 psig. He was killed.

Source:OSHA.gov