ChromiumChromium is a metal found in natural deposits as minerals containing other elements. Chromium is a hard, steel-grey, very brittle metal. It is classified as a heavy metal. After being refined from the mineral chromite, its compounds are used in leather tanning and in the production of chromic acid, pigments, and corrosion-resistant chrome products. The major use of chromium is in metal alloys such as magnetic tapes, paint pigments, cement, paper and stainless steel. It is also used as an ingredient in drilling mud, used to drill oil wells. Humans need a certain amount of trivalent chromium to maintain good health. Although, in other forms, chromium can be toxic to humans. Workers in plants manufacturing chromium products are at increased risk of lung and nose cancer. In 1974, Congess passed the Safe Drinking Water Act. This law required the EPA to determine safe levels of chemicals in drinking water that could cause health problems. These levels are called Maximum Contamination Level Objectives or MCLs...