Most (all?) LPG tanks in vehicles have "pop" valves. In the case of a fire, when pressure builds enough, the valve releases some of the gas. Results in a nice blowtorch effect in whatever direction the valve is pointed 'til the pressure drops, then the valve shuts off, and the blowtorch is out. For a minute or three, depending on the heat involved, how full the tank is, etc. But a BLEVE in a vehicle tank is very rare...