Re: Hydrogen
My father ran a company that made lock washers. They would drop red-hot washers into an oil bath to heat treat them. Occasionally it would catch fire so they chopped a hole in the ceiling to let the flames escape and rigged CO2 lines around the bath that would discharge when a handle was pulled. They didn't even stop the production line.
All was fine until a CO-OP found a water extinguisher somewhere and then they really had a fire.