Fowler Associates Labs

Static May be to Blame

Every year gas stations experience fires and explosions, some of which are due to static discharges.  We reported one such incident last year.   Aerosmith Car Explodes.  The latest report of an explosion was very close to the offices of the ESD Journal.  We took the opportunity to do a little investigation.

The following is an account of the accident. Please submit any comments you may have.  This situation is very serious and happens more than we would like to admit.  Reportedly it happens many hundreds of times per year.  The contractor who was installing the new pumps for the station below had personally seen 3 such incidents in the past 20 years.  All pumps are required to have electrical connection between the nozzle and ground.  This allows the car to be discharged before the gas in started.  Is this sufficient? What can we do to help reduce the number of car/gas/station explosions?  

Anderson,  SC Friday April 9, 1999

Two brothers pulled into the Texaco station on I-85 in Anderson county, South Carolina about 9:15 p.m.on April 8,1999 to get some gas (and some cigarettes) .  

The driver got out of the car and began to pump the gas into his Chevrolet Cavalier. He was joined by his brother who stood near the car while the gas was being pumped.  Their car was nearly empty when they stopped at the station.  After pumping about five (5) gallons of gas they were startled by a flame beginning in the car tank fill tube area.

 Flames erupted very quickly engulfing the gas nozzle and the hand of the man who was pumping the gas.  He immediately dropped the nozzle which continued to discharge gas onto the asphalt.  This gas quickly began to feed the flames which had spread to the pump body and up into the canopy of the station.  The man who had been the passenger of the car rushed over to the driver's door, opened it, jumped in and tried to start it only to find the driver - who was busy trying to extinguish the flames in the car gas tank fill area - had the keys.  

He threw the manual drive car into neutral and with the assistance of the driver pushed the car  away from the pumps and to safety. The station manager had heard the noises of the commotion and hit the emergency shut off switch which immediately stopped the flow of gasoline from the nozzle. The two brothers put out the flames in the pump area with fire extinguishers.

Both men received minor burns but required no medical treatment. The Cavalier will need a new tail light and paint job but thankfully this story does not have a tragic ending.  Everyone did a very good job containing the explosive situation.  

This station was undergoing renovations of its pumps.  All the old pumps were being changed out for the type with credit card  entry at the pump.  This pump had been installed  just ten (10) days before the accident.

The accident is under investigation by the arson squad of the Anderson Sheriff's Department and the insurance company. Many unanswered questions remain.  Was one or both of the men smoking?  They say not.  There was no evidence of smoking found at the scene.  However,  they were coming to the station for gas and cigarettes.  Did static cause the accident?  When the nozzle was placed into the fill tube of the car's gas tank, would not the static charge on the car have been grounded?   What would cause the flames to initiate after 5 gallons had been pumped?  A quick check of the pump by this reporter showed the nozzle to be electrically connected to the pump frame and most probably to ground as it was installed.  Could a person who had just slid across a car seat, go to an area where gas is being pumped  and discharge to the car or nozzle area and have this charge travel to ground through the nozzle thereby igniting the gas fumes which are being expelled by the tank being filled? Or was there an electrical arc in the car or pump?

Give us your comments.  They may help stop these accidents from happening in the future.