In a car crash, there are frequently showers of sparks from metal bits grinding against pavement. I'd like to see that test performed with an ignition source near the tank.
Here's a video from 2003 where BMW stuck a hydrogen tank and a gasoline tank in a fire and compared the results [1]. Not exactly what you were asking for - but demonstrates hydrogen being released at high pressure and ignited.
The caption from BMW is:
> Fire behaviour test, comparing a petrol tank and a tank filled with liquefied hydrogen. The heat from outside causes a rise of pressure inside the hydrogen tank. The hydrogen gasifies and emerges through a safety valve into the air, where it burns off. From the fuel tank liquid petrol emerges and causes a surface fire. Statements by Dr. Joachim Wolf, Linde AG "What that means for the car manufacturer – or for cars in general – when we transfer this hypothetical situation into reality: an accident happens, petrol runs out, and a car drives into the flames. It’s not very nice when a car is on fire and people have to be rescued. That’s the case with petrol. With hydrogen, if the fuel escapes then it disperses upwards. That probably offers much better options for rescuing people who may be trapped in the vehicles.""Hydrogen is no more dangerous than petrol: I think this test shows that. We see a clear blue flame that doesn’t produce as much heat as burning petrol. Hydrogen is not more dangerous, but it’s also no less dangerous than petrol. It simply poses different potential hazards."
I more or less agree with the statement that Hydrogen is not necessarily any more dangerous than the cars we are already driving around, but poses a different a different set of potential hazards. That being said - I don't think I would like to be an early adopter of hydrogen cars.
