Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) found large quantities of previously undetectable compounds from the family of chemicals known as PFAS in six watersheds on Cape Cod using a new method to quantify and identify PFAS compounds. Exposures to some PFAS, widely used for their ability to repel heat, water, and oil, are linked to a range of health risks including cancer, immune suppression, diabetes, and low infant birth weight.