It is hard to call per- and polyfluoroalkyl substances (PFAS) a category of "emerging" contaminants given the amount of attention PFAS is receiving these days, but the regulation of PFAS throughout the country is certainly still developing. Pennsylvania is the latest jurisdiction to propose drinking water standards for PFAS, and its proposed maximum contaminant levels (MCLs) are examined below.

What Are PFAS?

PFAS are a class of synthetic chemicals that have been used since the 1940s to make products that are resistant to water, heat and oil. These products include cookware, carpets, clothing, fabrics for furniture, paper packaging for food, and other materials that are resistant to water, grease, or stains. They are also used in firefighting foams and in a number of industrial processes.