idea

Cell phones are causing fires in fuel pumps. Refuelling fires are mostly triggered by static electricity igniting fuel vapors^[1]. Cars can build several thousands of volts of static electricity. A cell-phone battery is usually 6V and under.

references

[1]: Petroleum Equipment Institute is exhibiting result of investigations showing that sudden refueling fires are due to static electricity rather than cell phones. They even tried unsuccessfully to trigger fires using cell-phones.