nickel

Topical exposure to metals that contain nickel frequently causes contact dermatitis. Metallic nickel is widely used in industry in steels and alloys, batteries, fuel cells, electroplating, and ceramics. Nickel is also recycled from scrap metal and is emitted from waste incinerators, power plants, and cigarette smoke. The major route of occupational exposure is by inhalation.

Particulate nickel compounds are carcinogenic; they enter target cells after phagocytosis, with release of nickel ions intracellularly. Nickel appears to damage heterochromatin selectively and can inactivate tumor-suppressor genes by hypermethylation.47