A hundred years ago, cities and towns in America began adding chlorine to their population's drinking water as a disinfectant. Today, municipalities know that toxic chemicals are associated with chlorine and many of them have turned to alternatives. However, those substitutes now have recently come under fire with at least one expert saying that they also pose problems.

Chlorine reacts to certain organic matter contained in water, creating cancer-causing byproducts. Although the U.S. Environmental Protection Agency has said that risk from the byproducts is small, the agency pushed, with new rules, for communities to start relying on a related chemical called chloramine. But now the realization is that chloramine also has some bad byproducts called nitrosamines.

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