NTP taps disinfection by-products for study.

The use of chlorination to purify water supplies is considered one of the most important public health advances of the twentieth century. Following the 1908 introduction of widespread water chlorination, once-common diseases such as cholera, dysentery, and typhoid fever were practically eliminated. However, the chlorination cure-all proved to have a caveat: disinfection by-products (DBPs), which result from the reaction between the chlorine added during chlorination and organic material such as leaves and sediment in the source water. In the mid-1970s, certain DBPs were found to cause adverse health effects including cancer in laboratory animals.