ST. LOUIS - Two recent flash fires at service station pumps inspired Missouri officials to warn that people can't be too careful when grabbing a fuel nozzle.
In each case, the suspected mix was static electricity and gasoline fumes rising from the vehicle's fuel tank intake. As the theory goes, motorists generated a charge at their fingertips by the mundane act of getting off their car seats.
"You can create a lot of friction doing that," said Ron Hooker, of the Missouri Department of Agriculture.
If blaming one's posterior is cause for humor, the fires weren't so funny.
In Macon, Mo., a minivan burned up at a gas station on Nov. 17. Five children inside the van escaped safely.
The Macon Fire Department said the fire probably began when the motorist touched the nozzle at the end of fueling, making a static spark that ignited fumes. She was wearing a wool sweater and told firefighters she had been bothered by static all day.
In Hannibal, Mo., a pickup was damaged Dec. 26 in a similar fire. The motorist dropped the flaming nozzle onto the ground, spreading the flames.
"The guy went to grab the nozzle, and the next thing he knew there was fire everywhere," said Hannibal Assistant Fire Chief David Hymers. "He had been sitting in his truck because of the cold. The spark could have come from him sliding across his seat."
Hymers said the pump had a faulty ground wire, which is designed to absorb static. A Macon spokesman said he did not know whether the ground wire there was working.
Hooker, of the Agriculture Department division that regulates fuel pumps, said the state investigated 14 fires caused by static last year. No one was killed, but one man suffered burns to his arm, Hooker said.
Steve Wadley, one of Hooker's inspectors, said most of the pumps involved had good ground wires. "We wish we knew why this happened," he said.
Ron Leone, director of the Missouri Petroleum Marketers and Convenience Store Association, said government safety standards for fuel pumps require grounding systems. Leone called pump-nozzle fires "exceptionally rare things."
"But strange things do happen, and we encourage everyone to take the proper precautions," Leone said. "Our members comply with all the standards, but no system is absolutely perfect."
In each of the 14 fires, the motorist set the nozzle and got back into the vehicle during fueling. Presumably, the motorist released static while reaching for the nozzle, sparking vapors.
Hooker said the all of the fires occurred on days of low humidity, with temperatures in the 30s or colder.
Dale Bechtold, a meteorologist with the National Weather Service, said static electricity builds up quickly inside a vehicle when the heater is running because the humidity is greatly reduced. The ordinary friction of coats and sweaters makes things worse, he said.
Gas pump safety suggestions:
- After getting out of a car at a service station, close the door and touch another part of the vehicle's metal body to discharge any static electricity.
- Once you begin refueling, don't get back into the vehicle. Staying outside avoids the risk of recharging with static.
- Before returning the nozzle to the pump, touch your vehicle again.
- If a static-spark fire occurs, leave the nozzle in the fuel intake and get away. The attendant can shut off the pump from inside the station.