Per- and polyfluoroalkyl substances (known as PFAS) are long-lasting compounds that are showing up in soil, ground water, drinking water sources, even rainfall, and have been linked to cancer, liver damage, thyroid disease, and other ailments. By some estimates, this toxic family of chemicals can be found in the blood of nearly every person on the planet. Correspondent Lee Cowan looks at how the chemicals got here, and talks with families, farmers, and health advocates fighting for clean, safe water. Air Date: Aug 21, 2022