Several human studies have investigated the relationship between exposure to chlorinated drinking water and cancer. These studies were not designed to assess whether chlorine itself causes cancer, but whether trihalomethanes or other organic compounds occurring in drinking water as a result of chlorination are associated with an increased risk of cancer. These studies show an association between bladder and rectal cancer and chlorination byproducts in drinking water. Another study evaluated the potential carcinogenicity of chlorinated drinking water in rats and mice and found no statistically significant increase in tumors that could be related to the chlorinated water. EPA has not classified chlorine for carcinogenicity.
Chlorine is a greenish-yellow gas that is slightly soluble in water.
It is also used to disinfect equipment and utensils in beverage and food processing plants, and as an intermediate in the manufacture of a number of organic products such as antifreeze, rubber, cleaning agents, and pharmaceuticals. U.S. Environmental Protection Agency. Drinking Water Criteria Document for Chlorine, Hypochlorous Acid and Hypochlorite Ion . U.S. Environmental Protection Agency. Environmental Criteria and Assessment Office, Office of Health and Environmental Assessment, Office of Research and Development, Cincinnati, OH. 1993.