6/1/05 HazMat call— Responded with bunker gear and SCBA for “pool chemicals that got wet and was giving off gas”. We dumped and diluted the solution resulting from a 6 gallon bucket of Chlorine granules being left open in the rain. After everything was washed down with 600 gallons of water the bucket was found to have a 2-3″ layer crystallized in the bottom. ‘Someone’ screwed the lid back on the wet bucket. When I noticed I objected that it could explode, and recommended we open the bucket and fill it with kitty litter to absorb the water and just sit the lid on the top without screwing it down. The Chief called a chemical hotline and asked if Chlorine would explode. They said no, it wouldn’t burn or explode. The Chief was going to leave the closed bucket with the property owner for disposal. My chemistry probably isn’t precise, but roughly, Chlorine mixed with water steals the hydrogen and makes HCl and leaves O2 as a fee gas. The reaction produces heat which expands the gas. The property owner approached me and said what I was saying made sense. He was going to follow my suggestions. I couldn’t just drive off and leave him or his kids to discover whether or not it was dangerous. I walked over to remove the lid myself. It exploded as soon as I touched it turning the plastic of the bucket into shrapnel. The worst injury was from a shard penetrating at the top of my lip and going through my cheekbone to puncture my right sinus. I was lucky that I’d taken my helmet off. It may have taken my head off.