Exposure usually arises through hot metalworking processes, such as smelting and casting of zinc alloys, welding of galvanized metals, brazing, or soldering. If the metal concerned is particularly high-risk, the residue from cold sanding processes may also cause fume fever, even if the dose is lower. It may also be caused by electroplated surfaces or metal-rich anti-corrosion paint, such as cadmium passivated steel or zinc chromate primer on aluminium aircraft parts. Exposure has also been reported in use of lead-free ammunition, by the harder steel core stripping metal from the jacket of the bullet and barrel of the rifle.