Here's what I do: If I step into my shop to do anything other than drill, glue scales on, do some light filing or wet sand something I wear my respirator and usually turn on my dust collector, too. Although, my dust collector uses bags for woodworking, and I've seen more dust in the air after filing carbon fiber and G-10 than I would've if it hadn't been on, so I don't use it that much right now because I think the bags aren't fine enough to catch what I'm making. But, in any case, I pretty much wear a respirator all the time. Is it uncomfortable? A little. The main thing is it makes my neck sore after a while because it's a bit heavy. But, I see my chiropractor and I don't have to worry about killing myself with my hobby.
If you pay attention, you'll hear of an awful lot of knifemakers who have really bad health, quit working because of health reasons, etc. I'll bet if you could ask, most of them would say they regret not taking airborne particulates more seriously, but that's just a guess.
zinc makes you throw up and have stomach cramps after a couple hours past being exposed. i dot think there is any other side effects.
I wouldn't be too sure about that. What form is ziinc found in steel in? Metal fumes can cause "metal fume fever" and things like that. Zinc fumes typically don't, but depending on the form the metal is in (oxides, chlorides, etc) the effeccts can differ and have varying levels of toxicity.
The bottom line is, in my professional opinion, it's a lot better to err on the side of overprotection. Mike is right that a lot of the symptoms involved in these problems mimic other problems. "Gee, Doc, I got a cough, a fever, I'm feeling terrible..." "Her ya go, son. Take this antibiotic and you'll be all set. See you when I see you..." I used to have a patient who would turn yellow every now and then. His MD diagnosed him as having some sort of obscure genetic condition called Wilson's disease, but I think he sort of missed the part when the patient explained how he works on a clean-up crew in a food factory and sprays equipment down using super-heated chemicals that mist and fume, etc. I asked what kind of respirator he used and he had no idea what I was talking about. I asked about mouth, face and lung protection, skin protection, etc and he said "None." So, I think it was pretty likely the guy was overloading his liver with toxins, but what do I know?
So, anyway, don't expect your doctor to catch any of this because a lot of the signs and symptoms mimic less serious problems. Have a hair analysis done someday to check out if you're being exposed to high levels of heavy metals and you may be surprised (unless you're taking the proper precautions).
