Forever chemicals are a class of chemicals collectively known as per- and polyfluorinated alkyl substances (PFAS), which were first introduced in the 1940s.
Their high thermal and chemical stability, coupled with their ability to repel grease and water, make these chemicals uniquely suited for a variety of engineering and commercial uses. As such, they can be found in many consumer products, such as makeup, fire extinguishers, fast food wrapping, textiles, stain repellents and electronics. The actual number of PFAS in circulation worldwide has yet to be defined – though according to some resources, this number is well over 4,700 chemicals.