In a recent publication, researchers from Stockholm University and ETH Zürich published an article titled Outside the Safe Operating Space of a New Planetary Boundary for Per- and Polyfluoroalkyl Substances (PFAS). The article compares the most stringent international limits on PFAS with the levels of PFAS found in environmental media. For instance, the authors compared the levels of PFAS detected in rainfall in various regions of the world to the U.S. EPA drinking water advisory. Except for remote regions, i.e., Tibet and Antarctica, PFAS detected in rainfall around the world exceeded drinking water advisories. The authors remarked that “US EPA health advisories seem not to be practically reachable without investment of huge cleanup costs in drinking water treatment plants given that most drinking water sources on the planet will have PFAS levels above the advisory levels.” The authors note that they made “no attempt to determine which of the many guidelines . . . is based on the strongest empirical evidence on effects because such a judgment is outside of our expertise. The point that we want to make is that the most stringent risk-based health advisories are often well below environmental levels, and this should be of concern and a reason for taking stringent measures.”