Cell phones at gas pumps

I just saw a segment on the local news about a man who was burned by a flareup of the gasoline fumes while filling his tank (Here’s a link to the TV news webpage on the story: http://www.king5.com/business/NW_042502BUBcellphonefire.283ef13b.html ) The fire department said that the blaze was probably sparked by a static charge.

The news people said that the charge was probably applied to the man’s body when he sat in his car to get his cell phone. They mentioned that the plastic seats tend to cause this, and suggested touching the metal of the car to discharge yourself before pumping gas. But they said that’s the reason there are notices telling people not to use cell phones at the pumps.

I don’t get the connection. The way they described it, the same thing would have happened if he’d gotten in the car for a roadmap, a candy bar, or an inflatable sex doll. They didn’t tell me why the cell phone was particularly dangerous. [I’ve got a theory, but the news story didn’t really support it. This is one of the most irritating things about the newsbites you get nowadays. No detail.]

So, why are cell phones prohibited at gas pumps? And was the cell phone actually at fault in this Arizona case?

I think you should bear in mind that journalists don’t necessarily know anything about physics. I imagine they got confused between two different explanations as to the cause of the spark. I would guess that one guy told the journalist that the guy picked up static from the plastic seat from getting the phone, and another told him that mobile phones are forbidden in gas stations, and joined the two explanations together.
Presumably, static charge could have caused the spark but this has no direct connection with the phone. It is theoretically possible to get a spark from electronic equipment such as a mobile phone, but the argument is similar to that against mobile phone brain damage: the phone operates on a very small current and voltage, and is unlikely to cause sparks.
Read This article.

A thought I just had:
I would have thought that if gas companies thought there was a risk from explosion from mobile phones, the warnings would be larger, as they are for cigarettes, with a written warning that explosion may occur. As it is, signs tend to be just a crossed out picture of a phone. Perhaps this is done to stop people from hanging about too long by the pumps as this reduces the number of pumps available.