Wow! That's scary stuff Muddy. Many years ago and I'm talking roughly 60 years ago (I was 8-10 years old), we had a neighbor who was jumping his wife's car off with a pair of jumper cables. I don't know if he reversed the poles or if the battery had just built up a lot of gas and a spark ignited it, but it blew up in his face. I honestly don't remember what happened to him but I do remember it also got into his eyes. TBH, I remember it happening, but nothing after that. Weird.