Galvanized steel is also used in exhaust systems. The burner on my gas grill is galvanized.
From OSHA website:
Effects on Humans: Zinc oxide dust is primarily a nuisance dust, but exposures to high concentrations can result in respiratory system effects in humans. Volunteers inhaling 600 mg/m(3) zinc oxide dust for 10 minutes exhibited persistent rales, decreased vital capacity, coughing, upper respiratory tract irritation and substernal pain. Studies have reported that exposures to concentrations up to 430 mg/m(3) zinc oxide, resulted in chest pain [ACGIH 1991, p. 1755]. Inhalation of zinc oxide fume can result in metal fume fever. This in a self limiting condition characterized by flu-like symptoms which resolve within 24 to 48 hours [ACGIH 1991, p. 1755]. Repeated exposures to zinc oxide by skin contact have resulted in papular-pustular skin eruptions in the axilla, inner thigh, inner arm, scrotum and pubic areas [ACGIH 1991]. Epidemiologic studies of zinc refinery workers found no correlation between industrial zinc exposures and lung or other types of cancer [ACGIH 1991].