Internal studies and other documents show that 3M knew by the 1970s that PFOA and PFOS were toxic and accumulating in people's blood.
News that the Environmental Protection Agency pressured the federal Agency for Toxic Substances and Disease Registry to suppress a study showing PFAS chemicals to be even more dangerous than previously thought drew outrage this spring. The EPA pressure delayed the study’s publication for several months, and a similar dynamic seems to have been in play this July in Michigan, where Robert Delaney, a state scientist who tried to raise alarms about the chemicals six years ago, was largely ignored. Delaney, who delivered a report to his superiors about high levels of the chemicals in fish and the dangers they presented to people, has been heralded as prophetic. And both delays are being lamented as missed opportunities for getting critical information to the public.