For an explosion you need a well mixed oxygen + hydrogen atmosphere, which is nearly impossible to create in a blimp. Even the old Hindenburg did not explode, but rather its highly flammable nitro-cellulose skin burned and most of the Hydrogen likely escaped without ever catching fire.
I assume the explodey problem is why they didn’t use hydrogen but yeah if the risk is low enough that could be a good choice.
For an explosion you need a well mixed oxygen + hydrogen atmosphere, which is nearly impossible to create in a blimp. Even the old Hindenburg did not explode, but rather its highly flammable nitro-cellulose skin burned and most of the Hydrogen likely escaped without ever catching fire.