i would like to mention that zinc is not the only hazardous metal that smiths can encounter in their work. i have worked extensively with silicone bonze, and careless handling can result is very unpleasant flue-like symptoms. it seems that one can be exposed to bronze/copper through polishing (dust inhalation), forging (scale dust inhalation), tig welding (fumes), and even extensive handling of freshly forged metal with bare hands (the scale rubs of readily and is absorbed through the skin). i don't know what, if any, the long-term effects are. the symptoms usually subside in a day or two. i suspect all metalworkers would benefit from chelation therapy at some point in their career. and remember to daily thank your liver and kidneys for getting rid of all the bad stuff we absorb in our work.