Is that really true? Liquid gasoline does evaporate pretty quickly, yet doesn't need special metal tanks. Isn't propane sold and kept in pressurized tanks?
As I understand it, gasoline tanks on cars are unlikely to explode unless they are nearly empty.
The petrol in the tank will boil quickly and blow the tank apart, especially if it's already a bit melty. You won't get enough pressure for a proper "BLEVE" because the leaky plastic bucket won't hold enough pressure to stop it beginning to boil, but it'll throw burning fuel all over.
An automotive LPG tank is a bit different to the kind of thing you'd run your barbecue off with a "multivalve" that's got a float to shut off the filling port when it's full and act as a level gauge (similar to a petrol tank) and a pipe to pick liquid up from the bottom. You get "four hole" tanks with a vapour tap that you can use a normal regulator in, which is handy for things like motorhomes - same tank runs the engine and the cooker :-)
They're only pressurised to about 8 bar, low enough that you can use plastic pipe to connect them to the vapouriser at the engine. It's kind of nylon tubing with braid over and a PVC outer jacket, and it handles liquid propane at tank pressure.
If there's an overpressure because it gets really hot (like, car is on fire hot) it'll burp out a bit of gas which will cause a puff of flame but you're talking about something like a deodorant can on a bonfire (and don't tell me you've never done that).
Quite honestly, I'm more wary around the 15 bar air suspension tank and lines. That's where pressurised gases start to get a bit spicy.
That ... still sounds more dangerous than liquid gasoline to me. Though I suppose if it were cheaper and as plentiful then the world would switch. Gasoline was after all a byproduct of kerosine processing.
You think something that goes "puff" and emits a wee puff of flame every so often is more dangerous than something that just sprays liquid dynamite all over the incident?
I know someone who took a drill to a small propane tank and ended up life flighted to the hospital. Perhaps the equivalent with a gas can would be worse? I just don't see it.
You cannot burst an automotive propane tank, no matter how you might try. You could probably drill a hole in it with a decent drill bit (it's thick steel) or cut it open with an angle grinder, or even gas axe your way in.
But, as I say, deliberate stupidity aside, it's not just going to burst on you.
It's just not dangerous, period. There are multiple countries where every single taxi in the country pre-EVs ran on LPG, and now most of them still do though some get replaced by EVs. Ask anyone from there if they've ever heard of them blowing up. You'll get nothing but a "huh, what are you talking about?".
As I understand it, gasoline tanks on cars are unlikely to explode unless they are nearly empty.