I was talking to my girlfriend on the phone while filling up my gas the other night and she started yelling at me and hung up on me. I found out later that it is apparently very dangerious and it could start a fire/explosion. I seriously doubt that with the level of gas in the air that anything serious could happen doing this. They need to do a show on this. Fill a chamber with different levels of gasoline in the air, put a phone in it and keep calling it. What do you think?

This has been done. The conclusion was that the phone had nothing to do with the explosion. The problem was static generated by someone letting the hose go and wandering about, then coming back to a fume-laden area and discharging themselves, creating a spark at exactly the wrong place.
Over here, you have to have had to hold on to the filler hose while it is pumping - the lock was dispensed with years ago.
Its nothing to do with the phone - everything to do with the customer.

On the episode, it was clear that static electricity can cause the explosion. However when they did the episode with the celphone, they where only causing the phone to ring. The signal strength used ( and related power and energy) is different when the phone is ringing, when the phone is offhook and someone is talking, and when a phone is calling out. I wished they tried studying these conditions which carries the highest energy utlization and if it could cause a spark because the Myth says the person peeked near the nozzle while holding the phone on his ear. The celphone might just actually even be just an additional combination to the problem of getting in and out of the car because people tend to get back in the car to answer their phone and get back out to check the pump- human behavior. Do we know as well if celphone EM radiation increase the energy on a body thats already electrostatically charged?

The conclusion was that sparks generated could only happen if the filler, wandering about while the tank was being filled, generated static which then discharged on his return to the pump. The cellphone was totally irrellevant.
Immensely rare in the UK, as you generally cannot leave the pump unattended while filling.

regardless of whether you're talking on a phone r not, it reckless, irresponsible and just plain stupid to leave a petrol pump unnatended, a whole host of unpleasant things can occur whilst youre not looking.