Static electrical discharge is indeed a danger while refueling. If a person carries a static charge, a spark that is discharged anywhere near gasoline fumes can generate a fireball and/or explosion.
How can this be avoided? When you first grab the fuel nozzle, you are likely to discharge any static charge you are carrying. When fueling, make sure that the nozzle is inserted completely into the tank to minimize the possibility of fumes escaping. Do not re-enter your vehicle while fueling - this leads to friction, and can generate static charge.
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