A bullshit urban legend that said using your phone while pumping gas would potentially start a fire because of radio waves or some such and spontaneously start fires. It even went so far that gas stations put signs up telling customers to not use their phones.

What really happened was people would start pumping gas with those pumps that had automatic shutoffs, then they’d go sit in the car while it filled the tank to use their phone. When the pump automatically clicked off they’d get up and pull the gas nozzle out. This action caused static buildup getting into/out of the car seat and it discharged grabbing the gas nozzle. Sometimes enough of a discharge to start a fire. Took them a while watching security videos to figure out the sequence of events.

So indirectly it was using a phone that caused the fires, but not the phone itself.