My understanding, in regards to hydrogen, is that if the tank gets piereced, it will escape from the tank too quickly to have much of a reaction. It’s a gas, so it will assume the size of the container. If the container is the whole planet, it will spread itself out in an instant.
I think exploding tanks are not really an issue with hydrogen, at least from what I’ve been able to find out.
Hydrogen is a small molecule. It is all about leaks. The problems that postponed the recent Orion launch were all about hydrogen leaks. Believe if you will that NASA is fully incompetent while start-up automaker is not.