Answer:
Chlorine and fluoride (fluorine)
Explanation:
It sounds scary, but actually the amount of chlorine added to public tap water is not very harmful at all. They add this chemical to kill harmful pathogens and to make the water more purified. Some speculate that the chlorine can be absorbed by your skin while bathing and that the chlorine can cause kidney failure, but the amount that is added will have minute to almost no harmful effects.
We add fluoride to our water to yes, help with dental health especially in children. However, the U.S has had many issues over its history of having too much fluoride in the community water systems. By 2012, almost 70% of the U.S population was getting they water from (CWS) that had fluoride levels above the recommended levels.