Per- and polyfluoroalkyl substances (PFAS) are a class of man-made chemical compounds and a current, emerging concern to environmental health. PFAS substances have unique characteristics-resistance to heat, water, oil and stains-that make them useful in a variety of industrial applications and popular in consumer goods. Many PFAS are stable and long-lasting in the environment, acquiring the name "forever chemicals." Industrial use of some of these compounds has been halted; however, many derivatives are still in commerce and more are under development. PFAS are now found in many compartments of the environment.