We install hazardous area equipment in highly volatile environments..mainly gas and dust,and as such, have to follow very expensive rules and regs.A cell phone is unlikely to cause ignition..unless the vapour mixture is perfect and the ignition source is at the correct temperature.The biggest issue at fuel stations is the static being created when petrol is entering the storage tanks...thats why you see earth bonding straps across the vent and vapour recovery pipes.The no phone rule was a kneejerk reaction created by misinformed insurance companies ....however rules is rules...so turn off.