When Lawrence and Penny Higgins of Fairfield, Maine, first learned in 2020 that high levels of toxic chemicals called PFAS taint their home’s well water, they wondered how their health might suffer.

When Lawrence and Penny Higgins of Fairfield, Maine, first learned in 2020 that high levels of toxic chemicals called PFAS taint their home’s well water, they wondered how their health might suffer.

Scientists and regulators are divided over the threat posed by rising levels of a chemical called TFA.