Mike was a heavy smoker. If I had to guess, that would be the start of his health issues.
With the plastic, painting and lead work one has to assure himself of very adequate ventilation. I have a high volume exhaust fan i the ceiling of my work room and I leave the door cracked a hair for fresh take-up air while I am injecting or air brushing. Unless you're using a dremel or some other sanding apparatus on lead and creating very fine lead dust there's very little chance of inhaling any lead. I've been casting since I was 14 and am now 71 and am checked each year at my annual physical. Nothing lead related at all. There's a slight chance of lead absorption while handling lead but I've never worried about it, not have I worried about lead vapors since the lead pot does not get hot enough to create any lead vapors....lead would have to boil to create vapors and those temps are way out of a hot pot's league. The plastic injection and painting can be problematic if you're inside a closed area with little to no air exchange so you need to be careful of that. If you are "feeling different" while doing either it indicates you're not vented well enough. Many people wear respirators while doing these tasks, I just keep air moving away from me and do fine.
I make some custom balsa floats and have to sand the balsa to shape. The dust created while doing so has given me more breathing problems than any other of the tackle crafting I do. I mask up and do the sanding outside now so I can limit how much dust is in the air around me. And the shop stays cleaner. I'll even set a fan on the patio table while I am out there sanding if there is little breeze.
