Abstract: Employee #1, a job foreman, obtained an agricultural-type propane torch to warm a concrete septic tank that had been recently constructed. The tank needed to be protected from freezing temperatures overnight because the inside was going to be tarred the next morning. The nonregulated hand-held type torch was not equipped with a pilot safety shut down and was connected to a 100 lb lpg tank. The tank had three manholes with lids and there was a 4 in. hole at each end. Employee #1 lit the torch and inserted it into one of the holes while the other hole was blocked off to keep in the heat. The torch went out overnight because no replacement oxygen could be obtained to support combustion. When Employee #1 returned in the morning, he saw that the torch was out and attempted to relight it. Meanwhile, Employees #2 and #4 smelled propane. Employee #2 went to warn Employee #1, but did not reach him before he reinserted the lit torch into the tank, causing an explosion. Employees #1 and #2 were blown approximately 55 ft. Employee #3 was blown approximately 75 ft and Employee #4 was blown into an adjacent service truck. Employee #1 was killed; Employees #2 and #3 were hospitalized. According to the employees, Employee #1 had a severe head cold and possibly could not smell the propane. Employee #2 had told Employee #1 the previous evening not to use the propane torch, but Employee #1 did not have approved space heaters to heat the tank.