Are FCVs safe? What if they catch fire?

Hydrogen doesn't smell. Adding an odorant to a gas would be a simple thing, but from what I know, the fuel cell needs pure hydrogen. So an odorant might be possible without harming the stack.

As stated, it's an air fuel mixture in an enclosed space that is the real danger. Shooting a grill lpg tank won't cause a firely explosion without an external flame to ignite the escaping gas.

The tanks are made mostly from carbon fiber. Which is a decent insulator, and should contain pressures in excess of the tank's rating as a safety factor. I can't answer for exactly how long, but there should be a decent period of time before the contained hydrogen heats up to the point of rupturing the tank. The safety valve will go first; maybe some other fitting will fail in a fire also. In which case, the escaping hydrogen will ignite and feed the flames before an explosive, contained mixture can form. Eventually, the pressure of escaping hydrogen will get low enough that the flames can get inside the tank. Then there might be an explosion, but a much smaller one.

Another thing to keep in mind is that the largest amount of hydrogen on any of these FCVs is 5kg; which has about as much chemical energy as 5 gallons of gasoline. Catastrophic failure of a 10k psi tank will cause damage, but will do so even if the contained gas was nitrogen.

 

I think that FCVs are about as safe as gasoline vehicles as a whole, although I've made the joke myself about needing a parachute instead of a seat belt if you drive one.
FCV's have bigger problems than being associated with das Hindenberg.
It's a solution desperately in search of a problem to solve.

Big Phone has some FCVs in their fleet, and if I've taken some of the on-line training, although they haven't put me into one of those vehicles.
They're not very popular.
If I want an expensive, range limited vehicle that takes a while to fuel and is suffering from a recent spate of vehicle fires due to developmental problems, then I'll take a BEV!
At least you have places to plug them in everywhere in the US.

 

FCVs will probably bomb either way.

 

Note also that lpg is heavier than air, so bulk gas will pool in low places.

H2 is the lightest gas there is, so bulk gas very quickly rises. In most human developement, that will lead it to dissipate, not pool. Enclosed places, such as the buildings housing the Fukushima Dai-ichi nuclear plants, are where it becomes a hazard.

 

Hydrogen is lighter and will dissipate quicker, but it also has a wide range of air to gas ratios in which it is explosive and an even wider range at which it is flammable. Then it requires less energy to ignite.

Flammability limit - Wikipedia, the free encyclopedia