Because chromium occurs in ores, environmental levels are increased by mining, smelting, and industrial uses, Chromium is used in making stainless steel, various alloys, and pigments. The levels of this metal are generally very low in air, water, and food, and the major source of human exposure is occupational Chromium occurs in a number of oxidation states from crt to cr 6 oms are of biologic significance. Althou but only the trivalent (C an the trivalent compound is the most common form found in nature, the hexavlent form is of greater industrial importance In addition, hexavalent chromium, which is not water soluble, is more readily absorbed across cell membranes than is trivalent chromium. In vivo, the hexava is reduced to the trivalent form, which can complex with intracellular macromolecules, resulting in toxicity. Chromium is a known human carcinogen and induces lung cancers among exposed arcinogenicity in the lung is believed to be workers The mechanism of chromium (Cr reduction to C and generation of reactive intermediates, leading to bronchogenic carcinoma