PLEASE be extremely carefull to over-ventilate when working on galvanized material. I am a hobby blacksmith and know personally of 2 smiths who died
ugly deaths within 2-3 weeks of exposure to excess zinc fumes. Just long enough to write warnings to others before their family buried them! Sorry if I sound extreme but this is an isue close to me.
http://www.anvilfire.com/iForge/ Scroll down and go to "safety III"
metal fume fever