Attached is the picture of a BMW 318 TDS Gasoil Prepump. That prepump is literally inside the sealed fuel tank.
And it contains a small electrical motor, in which 12V of electricity is sent, mainly when the car is turned on.
How on Earth can that be without any risk of explosion? There can easily be sparks inside the motor! And if there were some air inside the fuel tank, it would explode ...
When I think we are told not to have a phone call when filling the gas tank ...