Centers for Disease Control and Prevention (CDC), the health effects of low PFAS levels in the environment are uncertain.However, the trouble with PFAS is that they are highly stable molecules and, therefore, don’t break down naturally, earning them the title “forever chemicals.” This means they steadily accumulate not only in the environment but possibly also in people’s bodies.The CDC note that animal studies suggest exposure to high levels of PFAS can affect growth and development, reproduction, thyroid function, immunity, and the liver.Around 97% of people in the United States have detectable levels of PFAS in their blood.Epidemiological studies link high serum levels of two particular PFAS — perfluorooctanoic acid (PFOA) and.