I wish there was a way to know for sure if a drum is hazardous or not. I've noticed mine is surprisingly cool when smoking- you can touch it without getting burnt. I would think at those temperatures, very little more could leach out after a good healthy burn-out. Unfortunately, I don't know for sure. I have a friend who wants one, and I'd love to build him one, but short of coming up with another SS drum, or popping for a brand new one, I'd hate to poison him and his family!
I'm very intelligent, but I mask it by doing stupid stuff.