Is having the radio on when filling up a disaster waiting to happen?

Dear Car Talk

Dear Car Talk | Jan 01, 2007

Dear Tom and Ray:

Am I right, or does my husband know what he's talking about? When my husband fills up his car with gas, he always turns the car off and removes the key from the ignition, which turns the radio off -- even if I'm busy listening to "Car Talk" on NPR! It drives me crazy, but he insists that having current passing through the vehicle is a disaster waiting to happen while filling up the gas tank. I'm sure he's being a little -- well, maybe a lot -- too cautious, because I often hear radios playing in other people's cars while they're filling up, yet I have NEVER seen a car blow up from an electric short during that process. Please tell him that I can safely listen to the radio while he's filling up! -- Cathy

RAY: He probably just doesn't want you listening to us, Cathy. And can you blame him?

TOM: There are several reasons why gas stations tell you to turn off your ignition while refueling. No. 1 is that if you accidentally leave your car in drive, or if it slips out of park or your dog knocks it out of park, the car could run somebody over. Or, worse, bash into the station's new Mountain Dew machine.

RAY: Reason No. 2 is that they want to lessen the chances that you'll drive off without removing the nozzle, yanking their hose out of its socket.

TOM: No. 3 is that they don't want anybody to be tempted to hop in your running car and steal it. It happens.

RAY: Reason No. 4 is that, with modern cars, running the engine with the gas cap off will turn on the "check engine" light.

TOM: And reason No. 5 is that there are various sources of ignition in a running automobile. Aside from the ignition system itself, there are relays, fan motors and other electrical devices that could, theoretically, provide a spark if a bunch of fuel were spilled and gasoline vapor enveloped the car.

RAY: In reality, most gas stations now have vapor-recovery systems, so vapors would only come from a fuel spill. It would have to be a pretty sizable spill to create enough vapor to cause a problem. So the exploding-car scenario is pretty unlikely. After all, how many knucklehead gas-station attendants have you seen pumping gas with a Tipparillo dangling from their lips, with a 3-inch-long, glowing ash hanging off the end of it?

TOM: And the odds get even slimmer of having any kind of problem if the engine is off and the key is only in the accessory position -- where it would be if you were listening to the radio. In fact, I can't really imagine a scenario in which you could ignite anything that way.

RAY: So tell your husband he can rest easy, Cathy. There's no problem with you listening to the radio while he refuels, as long as the key is in the accessory position. And if you want to turn the tables on him, tell him a greater spark danger comes from the static electricity he's building up because he's still wearing those sky-blue polyester leisure suits.

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