Abstract: At a water treatment plant, the interior of a 10,000-gallon hydrostatic tank which measured 30.5 feet in length, and 6 feet 10 inches in diameter, had been sand blasted, and was in the process of being spray painted. The spray paint consisted of a flammable mixture of toxic paint and thinners such as methyl ethyl ketone. Employee #1 had spray painted the tank for a period of time, and then he took a break. Employee #1 was either near the entry or actually reentering the tank when an explosion inside the tank occurred, propelling him approximately 15 feet from a make-shift platform into an adjacent building wall. The exact source of ignition was not discovered, but Employee #1 may have had a lit cigarette.