Battery relocation- Does anyone know of an actual hydrogen sulfide explosion incident?

2 friends had a battery blow in their face. We were always charging these old *** batteries (we were kinda poor back then) I always hook the battery to the charger and then the charger to the wall now. first guy ran for a hose and got rinsed off, second guy was in his garage so he went for the sink. He gave me that new Edelbrock 600 with the driver side void of all shine due to the acid. scary stuff.