Breathing radon can cause lung cancer. Drinking water containing radon presents a risk of developing cancer. Radon in air is more dangerous than radon in water. Inorganic Contaminants Antimony Asbestos Barium Beryllium Cadmium Chromium Copper Cyanide Mercury Nitrate Nitrite Selenium Thallium Technical fact sheets on Inorganic Contaminants Arsenic . Some people who drink water containing arsenic in excess of EPA's standard over many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting cancer.
Many communities add fluoride to their drinking water to promote dental health.
Each community makes its own decision about whether or not to add fluoride. This problem occurs only in developing teeth, before they erupt from the gums. Lead typically leaches into water from plumbing in older buildings. Lead pipes and plumbing fittings have been banned since August 1998. Children and pregnant women are most susceptible to lead health risks.