Arsenic

Arsenic is a brittle, steel-grey metalloid either extracted from arsenic ores such as arsenopyrite, or recovered as a byproduct of copper, gold, and lead smelting, where it volatilises during roasting and is captured in flue dust. It is used in pesticides and herbicides, in wood preservatives (chromated copper arsenate), in certain glass formulations, and historically in lead-arsenic alloys for improved shot hardness. Arsenic is acutely toxic by all routes of exposure, and its production and use are subject to strict controls in most local jurisdictions.