Abstract: At approximately 10:30 a.m. on November 4, 1997, Employee #1, age 2, was working alone in a 6 ft by 6 ft 2 in. wide by 33 ft 10 in. long trench to pressurize a new 12 in. natural gas pipeline with compressed air. The pipeline, capped with a metal end piece and a dresser #38 coupling, was being pressurized to prevent moisture and debris from entering the new pipe. The dresser #38 coupling, used to splice together two sections of natural gas pipeline, normally operated between 15 and 25 psi, with a maximum tested capacity of 60 psi. Employee #1 had introduced at least the test capacity into the pipe line and had intended to continue until 90 psi was reached. At some point between 60 and 90 psi, the coupling gave way, releasing a 600 lb blast of compressed air into the trench. Employee #1 received the full force of the blast, was pushed back 9 ft into the north trench wall, and then thrown forward between two boards on the east trench wall. He sustained head injuries, intense compression and hemorrhaging of major internal organs, with severe stippling and penetration of various body parts by debris from the trench. Employee #1 was transported by Med-A-Vac to the Washington Hospital Center Shock/Trauma unit, where he was pronounced dead on arrival.