RatherBeFlying: The Emergency Medical Aid text I worked through some decades ago advised immediately removing the gas cap from any damaged vehicle.
It's pressure that will lead to an explosion. These days you'd have to find and work the gas cap release by the driver's seat, then jam something in to keep the filler inlet open
Interesting that you said that. I would have guessed the opposite - that leaving the gas cap closed to prevent egress of fumes would be better, but I had an experience many years ago that probably supports your training:
Back in the 1970s (must have been 1979) during a gasoline shortage I passed a car at the side of the highway with a weird flickering light. I pulled over and realized it was flames inside the car. I ran back to try to give assistance, but by the time I tried to open the door the interior was fully engulfed and I couldn't tell whether there was someone in the front seat or not. This went from a small fire to flames shooting out of the windows in less than 60 seconds. Another guy ran up to lend assistance and we decided that if there was someone inside we were too late. He said: "maybe we should get away in case the car blows up". I said "that's just Hollywood, they don't really do that".
We started walking slowly away and that's when the car blew up
Gertrude the Wombat: Which indeed was the case - but nice of them not to bother to hang around outside and not to bother to tell the gathering crowd that there was nobody left inside the house who needed rescuing, eh?
So, funny you should mention that. After the car blew up we saw someone sitting on the nearby embankment, maybe 100 feet away from the fire. Turns out it was the driver. He just sat there while we were trying to rescue anyone inside! He said he was carrying extra gas cans in the back seat because of the shortage of gasoline, and then tossed a cigarette out the driver's window and that it blew back into the back seat and caused the fire. Not sure to this day whether I really believe him (maybe he torched the car for the insurance? dunno.). Still, nice of him to let us risk our lives trying to rescue him while he sat a safe distance away!!!