Abstract: Employees #1 and #2 were conducting a safety inspection of an acetylene generator. Employee #3 was standing outside the generator room about 5 ft away observing Employees #1 and #2. The acetylene generator was drained and flushed with water. Employee #1 then removed the inspection plate and used a hose to wash the generator's inside walls. While he was hosing the walls, he instructed Employee #2 to open the valves on top of the generator. As Employee #2 was opening the valves, an explosion occurred within the generator room, killing Employee #1 and burning Employees #2 and #3. Apparently, acetylene fumes within the room ignited.