It is a myth that mobile phones are a potential source of ignition when around fuel bowsers or while refuelling.
There has not been one confirmed instance in the world where fuel vapors have been ignited due to the close proximity of a mobile phone.
The instances of vapor igniting at petrol stations especially and predominately in North America are due to weather conditions being conducive to static electricity discharge.
Rules regarding the use of mobile phones around petrol stations will soon be relaxed.