I think I know where all the Cancer is coming from >Bromodichloromethane is part of a group called trihalomethanes (THMs).Dichloroacetic acid is part of another group called haloacetic acids (HAAs).Both form when disinfectants like chlorine react with natural organic matter (like plant material) in the water. This is a tradeoff of making water microbiologically safe.2. Are they dangerous?In high amounts over long periods, both THMs and HAAs have been linked to increased cancer risk and other health concerns.But in the U.S., levels are tightly regulated by the Environmental