PFOA and PFOS have been found in the drinking water of 200 million Americans, including 6 out of 10 Illinoisans.

The administration said it wants to rescind and reconsider whether limits are needed for four PFAS that chemical companies are still producing and using in the U.S. — despite known health risks.

Some environmental groups argue that the EPA can’t legally weaken the regulations. The Safe Water Drinking Act gives the EPA authority to limit water contaminants, and it includes a provision meant to prevent new rules from being looser than previous ones.