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Mine Safety and Health Administration
MSHA's Occupational Illness and Injury Prevention Program
Health Topic

Your Health Comes First!


Arsenic [chemical symbol As; CAS 7440-38-2] is a metallic element that is insoluble in water, brittle, silver-gray in color and lacks odor. While arsenic occurs to a limited extent in nature as a metal, it is most often found in association with other metals, particularly copper, gold, silver, lead, and zinc. Common minerals containing arsenic include arsenopyrite, orpiment, realgar, enargite, and arsenolite. Another common source of arsenic exposure is from wood which has been pressure-treated with chromated copper arsenate.

Miners are most often exposed to arsenic contained as an impurity in the valued mineral or ore of interest. When the ore is smelted to obtain the desired metal, the arsenic is given off as a by-product. Generally the by-product is arsenic trioxide [chemical formula As4O6; CAS 1327-53-3], which is used industrially as a raw material to make different compounds including pesticides. Other names for arsenic trioxide include white arsenic and arsenious oxide. Moreover, miners cleaning dust collectors, flues, and furnaces must be made aware that flue dust contains a lot of arsenic. Arsenic emitted from the stacks at a smelter is partly responsible for the dead vegetation and moon-like landscape around a smelter.

Health Effects

Arsenic affects the skin, mucus membranes, and internal organs, and demonstrates short- and long-term adverse effects including cancer. Therefore, miners should be trained to avoid exposure to arsenic through skin contact, ingestion, and inhalation.

Skin and mucous membranes

Arsenic compounds are corrosive to the skin. Brief contact with arsenic has no effect; however, prolonged contact results in congestion due from excess blood; later pus-filled pimples develop. Moist mucous membranes are sensitive to the irritant action. The membrane lining the inner eyelids (conjunctiva), the moist and macerated areas of skin, the eyelids, the angles of the nose, ears, mouth, and the respiratory lining are also vulnerable to arsenic's irritant effects. Miners exposed to arsenic may develop holes in the tissue dividing the nose (septum).