When I was in High School we did a play that involved a smoking machine. We asked the science teacher for some chemicals that would make smoke. He must have mixed them wrong, because when we lit it(it was in a tin can on a piece of wood) it made A LOT of smoke- and got hot enough to melt the can, and burn a hole in the hardwood stage. The fire curtain came down, the school was evacuated, the fire dept came, and the teacher got into trouble.
That was in 1969, and the patch in the stage is still there.

On a more serious note, our condo complex used to collect money for a fireworks display every July 1. We would spend $500- $1000 on fireworks. It was my job to set them off. I lit a big cannon thing with the fuse on the side, and it appeared to go out, so I approached it, bent down to blow on the fuse, and it went off. I did not have hearing protection and have lost some hearing in my left ear because of this utter stupidity on my part.

Also a distant relative of mine when I was a kid blew his leg off building a bomb in his basement.