Abstract: Employee #1 was hired to replace the pop off valves on tanks. Employee #2 gave Employee #1 a diagram showing where the holes were to be cut. Employee #1 was using a cutting torch while atop a fuel tank, which contained 224 gallons of #2 diesel fuel. As Employee #2, who was watching the operation, started to walk away, he heard the torch pop, followed by an explosion. A fire ensued. Employee #1 was killed instantly. Employee #2 was burned on 60 percent of his body. The cause of the accident: Employee #1 was using an open flame too close to flammable or combustible vapors. He was using a portable Trailblazer 44D diesel welder mounted to a trailer, attached to a pickup truck.