Abstract: At approximately 1:00 p.m. on August 18, 1998, Employee #1 was performing hot work (i.e., welding) on the dump pipe of the tanker truck when residual flammable vapors in the piping ignited. The flame propagated up the pipe and into the tank truck causing an explosion and killed three people. Two were employees, Employee #1, and #2, and another individual, who was a visitor to the site. The tanker truck delivered a load of petroleum containing water the previous day. However, flammable hydrocarbon vapors still resided in the tank car prior to the hot work, which subsequently contributed to the accident.