I weld on a daily basis sometimes inside ss tankers and I can tell you from experience to protect yourself from any welding fumes most any in a confined area will cause health problems use a respirator if possible the local welding supply should sell them to fit under a helmet and you can use vineger (is that spelled right?) to clean off galvanizing in some instances (but the fumes are almost as bad ;P) but this depends on how heavy the galv. is and the method used to apply it