Abstract: At approximately 2:39 p.m. on September 25, 2002, Employee #1, a welder in a radiator repair shop, was working on a hairline crack in a used 29.25-inch diameter by 55-inch long, aluminum diesel fuel tank that had been built in 1990 for Freightliner. He was using a Miller Dialarc HF electric welder, Model Number RFG-27A, Serial Number JE758946, which had been purchased by the employer approximately one year earlier. As Employee #1 applied heat to the 150-gallon fuel tank, it exploded. He sustained burns over 70 percent of his body and was killed. At the time of the accident, three coworkers were in an adjacent room performing other radiator repair activities, but none of them were injured. The fuel tank had been brought into the shop for repair by a friend of Employee #1. There was no work order and the tank had not been cleaned or purged. Although the employer did not normally repair fuel tanks, it was noted that used fuel tanks had been successfully repaired in the past.