It was formerly believed that sparks from a cellphone might ignite gasoline vapor, however even a brief analysis of that theory reveals it to be nonsense.
There will be a different type of fire if your cellphone is sparking, and that fire doesn’t need to start when you’re holding it in your hand. Owing to the necessity for safety insurance, it is forbidden and there are signs up on the pumps barring cellphone use.
Similar signs warning against leaving automobiles alone while being pumped are there for the same reason. It’s true that you could make a phone call or leave the car and fetch a snack from the store, but if something goes wrong, you probably won’t notice it.
If the automatic cutoff fails and the pump continues to run after the tank is full, it’s a safety and financial risk that must be avoided.
When the TV show MythBusters investigated the problem of smartphones, it discovered that individuals leaning against the car and rubbing metal to build up static electricity is the danger, but from video footage, it tends to look like the phone is the culprit.