By Britt E. Erickson | C&EN | July 22, 2025 Read the full article by Britt E. Erickson (C&EN) "A dairy farm in Arundel, Maine, triggered an alarm in 2016 when high levels of perfluorooctanesulfonic acid (PFOS) were detected on the property in a monitoring well for a public drinking-water system. The chemical hasn’t been produced in the US since 2002 but is one of many per- and polyfluoroalkyl substances (PFAS), often called forever chemicals, that persist in the environment.