According to the New York State Department of Health, the available information on the health effects associated with PFOA and PFOS, like many chemicals, comes from studies of high-level exposure in animals or humans. Less is known about the chances of health effects occurring from lower levels of exposure, such as those that might occur in drinking water. As a result, finding lower levels of chemicals in drinking water prompts water suppliers and regulators to take precautions that include notifying consumers and steps to reduce exposure.
PFOA and PFOS have caused a wide range of health effects when studied in animals that were exposed to high levels. Additional studies of high-level exposures to PFOA and PFOS provide evidence that some of the health effects seen in animals may also occur in humans. The most consistent findings in animals were adverse effects on the liver and immune system and impaired fetal growth and development. The United States Environmental Protection Agency found that there is suggestive evidence that PFOA and PFOS cause cancer based on studies of animals exposed to high levels of these chemicals over their entire lifetimes.