Chromium metal occurs naturally and can be found in rocks, plants, soil and in volcanic dust and gases. The substance is also used in plated metal production and in wood preservation. Hexavalent chromium causes lung cancer, according to the Environmental Protection Agency (EPA). The EPA has set regulations for chromium exposure to protect the public's health. For drinking water, the limit is a maximum contaminant level of total chromium of 100 ﾵg/L (100 ppb) for public water systems. Air emissions are also monitored. Many workers are exposed to chromium metal through their job. The Occupational Safety and Health Administration has limited exposure during an 8-hour period to 5 micrograms. Chromium III is different from hexavalent chromium and has a different function. The element is needed in our bodies to metabolize sugars and fats. A deficiency of this element can cause health problems. Individuals who suffer from chromium deficiency may take chromium supplements.