1994 Saturn SL2: Case Study Fuels and Ignition

Underside shows reduction in wheel base to rear. Fuel tank at arrow is in crush zone forward of rear axle.

Fuels: All impact damage was to the rear of the vehicle. Only gasoline and brake fluid were in the crush zone, and there was no indication that brake fluid was in the region of burn damage. The Taurus came to rest remote from the Saturn and was not involved in fire. Consequently, gasoline from the Saturn gas tank was the only possible liquid fuel source. The rapid rate of fire initiation and propagation was consistent with a fire fed by liquid fuel. Also, during the inspection almost three months after the incident, gasoline leaked from the tank to the ground when the vehicle was rolled onto the passenger side. The leak could have been from a dislodged sending unit, breached fuel lines, filler, or tank. No leaks were observable in situ and the tank could not be removed for further inspection.

Undercarriage of Saturn; rear is down in photograph. Arrow pointing from bottom to top identifies the plastic fuel tank and associated shielding. Arrows from top to bottom point to underbody scrapes.

Ignition: No definitive source of ignition was identified. A witness observed sparks under the vehicle during or immediately after impact. The road was dark with no artificial lighting that would have obscured the visibility of sparks. By the witness description, the volume of sparks was most likely to have been produced mechanically. Several undercarriage surfaces, including the exhaust pipe, showed evidence of scraping against the pavement. There may also have been mechanical sparks from metal-to-metal contact between vehicles and from crushing metal surfaces within the Saturn. Electrical sparks and exposed hot filaments were present from energized lights on both vehicles.

View looking down behind driver’s seat (frame of seat in foreground), through torn sheet metal. Dark, burn damaged region of plastic fuel tank visible through tear.