Gasoline is hard to oxidize fast enough, but hydrogen is not.
The LFL/UFL (Lower/Upper flammability limit percentage - the min/max amount of fuel vs air you can have and still burn) for gasoline is 1.4/7.6 - that's a pretty narrow range. But hydrogen is 4/75, so hydrogen will burn in virtually any circumstance.
Hydrogen is, however, lighter than air, so it tends to escape upward before, or while, burning, which limits damage tremendously (except in a tunnel).
The LFL/UFL (Lower/Upper flammability limit percentage - the min/max amount of fuel vs air you can have and still burn) for gasoline is 1.4/7.6 - that's a pretty narrow range. But hydrogen is 4/75, so hydrogen will burn in virtually any circumstance.
Hydrogen is, however, lighter than air, so it tends to escape upward before, or while, burning, which limits damage tremendously (except in a tunnel).