When water flows out of the faucet and into a glass, it usually appears clean and healthful. A report released Wednesday, though, found hundreds of harmful contaminants across the American water supply that can cause cancer, developmental issues in children, problems in pregnancy and other serious health conditions.

“There are chemicals that have been linked to cancer, for example, that are found above health-based limits, or health guidelines, in the water of more than 250 million Americans,” said Nneka Leiba, director of Healthy Living Science at the Environmental Working Group, or EWG, an independent nonprofit organization that released a detailed account of the contaminants.

EWG, in conjunction with outside scientists, assessed health-based guidelines for hundreds of chemicals found in our water across the country and compared them to the legal limits. The law often permits utilities to allow these dangerous chemicals to pollute our waters.

In Illinois, EWG tracked contaminants across the state’s water supply, finding a total 0f 94 contaminants statewide. The following 10 contaminants have been detected above health limits:

  • Arsenic which is linked to cancer
  • Chromium (hexavalent) which is linked to cancer, liver damage and productive system damages
  • Total trihalomethanes (TTHMs) which are linked to bladder cancer, skin cancer and fetal development issues
  • Bromodichloromethane which is linked to cancer, harm to child and fetuses, as well as reproductive difficulties
  • Dibromochloromethane which is linked to cancer and harm to fetuses
  • Chloroform which is linked to cancer and fetal development issues
  • Dichloroacetic acid which is linked to cancer, as well as reproductive difficulties
  • Trichloroacetic acid which is linked to cancer and potential problems during pregnancy
  • Radium-228 which is linked to cancer
  • Radium-226 which is linked to cancer

These seven contaminants were detected above legal guidelines in Illinois:

  • Nitrate and nitrite which is linked to cancer and fetal development issues
  • Total trihalomethanes (TTHMs) which is linked to cancer and fetal development issues
  • Arsenic which is linked to cancer
  • Nitrate which increases cancer risk and can oxygen deprivation in infants
  • Radium, combined (-226 & -228), which are linked to cancer
  • Haloacetic acids (HAA5), which are linked to cancer and harm to fetal growth and development
  • Barium, which is linked to harm to the kidneys, heart and blood vessels, as well as high blood pressure

“There are more than 250 contaminants across our nation’s drinking water,” said Leiba. “About 160 of those are unregulated. And that’s a big concern because if a chemical is unregulated, that means it can be present in our water at any level — and be legal.” Most of the water in the United States comes from local utilities that measure contaminants in their water supply, but this data can be difficult to obtain.