In this article, Ed Calabrese argues that current U.S. PFAS regulations are based on the long-standing assumption that any exposure, no matter how small, carries some degree of risk. Citing three recent papers, he contends that many PFAS compounds instead exhibit hormesis—a biphasic dose-response in which very low exposures trigger adaptive biological responses while higher doses become harmful. If correct, he argues, current regulations targeting single-digit parts-per-trillion concentrations may substantially overestimate the health risks posed by these extremely low exposures.

Calabrese argues that the implications extend far beyond toxicology. He contends that spending hundreds of billions—or even trillions—of dollars to reduce PFAS concentrations from already low levels may provide little measurable public health benefit while imposing enormous economic costs on municipalities, manufacturers, and consumers. He calls for an independent scientific review of current PFAS regulations, greater use of cost-benefit analysis in environmental policy, and a shift away from the assumption that persistent chemicals are necessarily harmful at every detectable concentration.