The EPA has released drinking water health advisory levels for four per-and polyfluoroalkyl substances (“PFAS”), including revised target levels for PFOA and PFOS.  The updated advisory levels are based on new science that indicates that some negative health effects may occur with concentrations of PFOA or PFOS that are near zero.  Accordingly, the new advisory levels are set at 0.004 parts per trillion for PFOA and 002 parts per trillion for PFOS, which are several orders of magnitude lower than levels set by the Obama EPA.  While health advisory levels are not enforceable in their own right, many states use them as the basis for binding, drinking water standards, and the EPA uses them to set cleanup targets for PFAS contaminated sites.  The advisory levels will also be used to aid the EPA in its formal designation of PFOA and PFOS as “hazardous substances” under the Superfund Program.