Hydrogen dangerous?

So the other day someone was trying to tell me that hydrogen was an unsafe fuel. Basicly the argument came down to the fact that the hindenburg blew up, hence hydrogen is bad. So the other day while i was feeding my car, its evil food, i noticed this.
Warning label at gas station Warning on gas station Warning on gas station

What i wonder is why you have to turn your cell phone off…could your cell phone cause you to blow up while fueling? most likely its cause people on cell phones act like zombies. And you know how dangerous zombies are.