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.

The Environmental Protection Agency will rescind and reconsider drinking water standards for four chemicals that have been linked to a range of illnesses.

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.