EPA Advisers Debate How Much of a Common PFAS Is Hazardous

A PFAS commonly ingested by people and found in drinking water sources can harm more parts of the human body than the EPA’s preliminary analysis shows, a scientific advisory panel said Friday.

The scientists’ opinions varied, however, on the importance the Environmental Protection Agency should place on certain human studies that found the chemical weakened children’s immune response to tetanus and diphtheria vaccines. The agency used those studies to estimate a dose of the chemical, perfluorohexanesulfonic cid (PFHxS), that if exceeded and ingested daily for a lifetime could be harmful.

The agency’s and state regulatory offices combine the dose ...