Fireball !!!
Probably make the Ford Pinto look like a fire cracker.
That's been one of the more entertaining myth's of hydrogen powered vehicles, notwithstanding the fact that it simply isn't true.
BMW had 5 and 7 Series hydrogen powered vehicles back in the early 2000's (2001-2003) that drove from the east coast to the west coast on nothing but hydrogen fuel.
The cars performed flawlessly.
I managed to drive one of the 7 Series hydrogen powered vehicles when they were in Chicago at that time. I couldn't tell the difference driving the hydrogen powered 7-Series vs. the conventional gasoline powered 7-Series. Both were literally a dream to drive.
As an FYI, I'm not a "green power" nut and my interest in hydrogen powered vehicles back then, as it is today, is purely in the interest of the United States of America achieving energy independence so we stop sending hundreds of billions of dollars a year to turd-world islamic states that hate us and want to kill us.
I've also purposely not commented in this post about the cost effectiveness of hydrogen powered vehicles. All I will say on that topic is that like any other "new" technology, it's expensive as all hell when it's first created however commoditization, mass production and mass acceptance always drives the cost down to an affordable level.
Henry Ford knew that with the Model T and all the technology and work process innovations it drove.
Toyota has done testing of the hydrogen storage tanks. They were impenetrable to bullets - even armor piercing.
It's not much different than a vehicle with a propane or natural gas tank.
Hydrogen is more easily ignited than gasoline vapor. But, hydrogen rises quickly and disperses. As long as it isn't in an enclosed area, the danger is actually less.
This is an interesting set of pictures showing a hydrogen leak vs. a gasoline leak. The burning hydrogen vents straight up, but the gasoline pools and envelopes the entire car. However, as the article notes, that wasn't a crash test.
Hyundai and GM have performed crash tests:
Hyundai Tucson Hydrogen FCV Prototype FMVSS 301 NHTSA Rear Impact (30 Mph)
A Hydrogen Explosion Rattles Nerves, but Fuel-Cell Cars Have a Good Safety Record
In both cases, the hydrogen tanks in the vehicles did not rupture, or even leak. The "explosion" in the title refers to an accident at a refueling station, not a vehicle.
Toyota has also done crash testing of their Fuel Cell Hybrid Vehicle (FCHV):
http://www.toyotaaruba.com/readBlob.do?id=134
See the upper right of page 10.
I’m sure they were saying the same thing when the idea of carrying around 20 gallons of gasoline was introduced...