Health effects of niobium Niobium and its compounds may be toxic (niobium dust causes eye and skin irritation) , but there are no reports of human being poisoned by it. Apart from measuring its concentration, no research on niobium in humans has been undertaken. Niobium, when inhaled, is retained mainly in the lungs, and secondarily in bones. It interferes with calcium as an activator of enzyme systems. In laboratory animals, inhalation of niobium nitride and/or pentoxide leads to scarring of the lungs at exposure levels of 40 mg/m3. It must be placed in a protective atmosphere when processed at even moderate temperatures because it tends to react with oxygen, carbon, the halogens, nitrogen, and sulfur. The metal is inert to acids, even to aqua regia at room temperatures, but is attacked by hot, concentrated acids, and expecially by alkalis and oxidizing agents. -- No research? I'll pass thanks!