PFAS is a class of chemicals that can linger almost permanently in air, water and soil. Research suggests they are associated with a variety of health issues, including cancer.

For the first time, the Environmental Protection Agency has established national limits for six types of per- and polyfluoroalkyl substances in drinking water.

The substances, known by the initialism PFAS, are nicknamed “forever chemicals” because they barely degrade and are nearly impossible to destroy, so they can linger permanently in air, water and soil.

As a class of chemicals, PFAS have been associated with a higher risk of certain cancers, heart disease, high cholesterol, thyroid disease, low birth weight and reproductive issues, including decreased fertility.

Most people in the U.S. have PFAS in their blood, according to the Department of Health and Human Services.