The Reason Why We Can't Use Cell Phones in Petrol Stations...

Even though Mythbusters busted this, the reasoning is that there is a minute chance that a spark from the cell phone (either static discharge or from the battery itself) could ignite any gas vapors around your vehicle. This is the same reason that a lot of gas/petrol stations also advice you not to keep entering / exiting your car while filling your tank (especially in cold weather when static buildup is the greatest) to prevent the chance of static discharge igniting any gas vapors.Also, and this is seldom said , it can cause you to become distracted while filling your tank and if the auto shut-off  feature is not working, could cause you to spill quite a bit gasoline on the ground prompting a HazMat spill cleanup and a greater risk of fire from the gasoline runoff.