Yes, but notably you can design to reduce the risk of leaking hydrogen. If the areas around the tanks are designed to allow any leakage to vent before it reaches dangerous levels, you can reduce the risk. Yes hydrogen is flammable, so tanks of it are dangerous. Jet fuel is also quite flammable, and we’ve used that for a long time.

This is all in contrast to the design of the Hindenburg, which was specifically trying to hold onto a bunch of hydrogen in the flammable regime