It isn't that bad. The Hindenburg doesn't give a good picture, the hydrogen was surrounded by a doped fabric with aluminium flakes in it. The military used the same aluminium powder-cellulose mix as a type of napalm, that's what you see burn, the hydrogen went whoosh straight up in the air away from the people. If you do set hydrogen on fire it goes off very quicky and at the same time floats away. You get flash burns which are bad, but in an open space it wouldn't set off other materials, particularly modern automotive ones. Petrol in a pool or worse still on your skin or clothing is just as nasty or maybe even worse. The mixture thing to get a rocket fuel type reaction is as hard as getting petrol to explode rather than just burn, you need to contain it and control it, a lot harder when it's trying to float off.
If you look at the hose they fill up with you'll see it's thick. I'm guessing there is an outer hose that uses vacuum to seal the connection and at the same time sucks up any that's there when the connection is ended. The basic technology is well tested with LPG. It's only the fact that health and safety people came about 10000 years after we discovered fire that lets us have petrol at all, it's really not such a great fuel we are just used to it. The fuel companies won't allow their stations to burn down, so if this is ever a practical fuel filling up won't be a big hassle.
The thing with Hydrogen to me is that it isn't a fuel in the sense of long term stored energy unless you can go to Jupiter and mine the stuff. If you are running an atomic power station to create a chemical energy storage (H2O plus electric makes H2, react the H2 in the fuel cell you get the electricity back plus water) you've got to dispose of the spare element (O2 plus who knows what else). The old idea of the oxygen being something you can just release isn't true as it would change the chemical balance in the air and cause a green house effect? Will they pump the waste into huge greenhouses and get plants to grow quickly and release clean air? Why not just store the electricity? Batteries are improving fast and fuel cells contain similar nasty heavy elements, so I wonder which will win.
Andy
