Forever chemicals, also known as per- and polyfluoroalkyl substances (PFAS), are a pervasive group of compounds that have been linked to a number of cancers and other illnesses. The toxic substances have become widespread in the air, soil and water via industrial discharge and are found in a number of common household items, from cookware to dental floss to stain-resistant furniture. And many of the products in which they have been detected including waterproof makeup, workout leggings and period products " are primarily marketed toward women. In May 2022, a team of researchers at the Massachusetts-based Silent Spring Institute published a study ... looking at the presence of PFAS in underwear and several other consumer items. Among those products was menstrual underwear. Research released in August ... also found indicators of PFAS in some period products, including wrappers for several pads and some tampons and outer layers of menstrual underwear. A 2021 study ... tested 231 makeup products and found that 63 percent of the foundations, 58 percent of the eye products, 55 percent of the lip products and 47 percent of the mascaras it looked at contained high levels of fluorine. The Environmental Working Group has identified 300 cosmetic products from 50 different popular brands that contain PFAS in its Skin Deep database. The advocacy organization found that 200 of these products contain PTFE, which is also used in Teflon pans.