Welding Near Car Gas Tank. Our method was to drain the tank of fuel then refill with water to just below the crack then fill the void left above with nitrogen leave a trickle flow of nitrogen on throughout the welding. You can use a heat shield if youd like just for an extra measure of safety.
We often set our Ranger 8s on fire because we weld overhead and the sparks come down and hit the gas tank on the unit. Get a welding blanket and cover that tank. Full tanks dont explode but a hole can feed a fire for a long time.
A contract welder was killed while welding on a catwalk located over a 9300-gallon waste oil storage tank at the Philip Services Corporation PSC.
As other people have said its the fumes that are flammable. Make sure you drain the tank and flush with water to get all the gas fumes out. Check for leaks around sending unit and or hoses make sure you are not welding close to the vent of the tank and maybe have a fan blowing air over and around the tank just as a precaution to carry away stray gas fumes as well as a piece of sheet metal keeping sparks from falling on the tank and as flip said tank should be full of gas but after all of this it might be easier to pull the tank please. You can use a heat shield if youd like just for an extra measure of safety.