These guys are friends of mine. They're very much into blowing things up, this one just kind of backfired. I feel bad that they are in the hospital and about what awaits them upon their return. One of the said that if this had happened in the middle of nowhere, they would have just patched themselves up and gone on with their lives.
I don't negate the fact this this is an 11 on the 1-10 stupid scale. However, they are just kids. I hope they learn from this.

It was an OBA canister, they happen to be on the last boat in the Navy to have them. Though, she's being fitted for SCBAs currently.