The subject of whether or not to use galvanized steel is one that gets reviewed pretty regular here. Yes, zinc fumes are not healthy. But the risks are probably negligible in a UDS. Locate and read the thread " UDS and Galvanized" There you will find a PDF about zinc poisoning.
Dr. Mark (STL)
Ph.D. (honorary) Bovine $hitology
A thin line separates paranoia from an acute understanding of reality.