I used to work for a telephone company years ago. To make some extra money I had an occasional job helping a guy installing the batteries for the telephone switches. When the cells were assembled they were connected by led bridges welded with Hydrogen/Oxygen torch.
One time we were assembling two batteries at some plant and needed to move our stuff from one building to another. My boss and I carried the O2 bottle and local maintenance guys were carrying the H2 bottle. My boss told them to put the valve cover on it but it was ignored saying it is easier to carry without it on. While walking across a railroad track one of the guys tripped, they dropped the bottle and the valve hit the rail and broke off. The bottle flew into a maintenance building made round about a foot big hole in the brick wall then hit a work bench inside of the building and pushed it out on the other side making about garage door size hole there.
