Perfluorooctane sulfonate (PFOS)
Old formulations of Scotchgard
This miracle product was developed in the early 1950s, when a 3M scientist spilled some synthetic latex onto her white tennis shoes and found that it prevented further staining. PFOS became the darling of the upholstery and carpet industries for decades. Fabrics and carpets were impregnated with it at the plant, and clean-freak homeowners could buy the stuff in spray-on form in a can. In 2000, however, 3M announced it would phase out PFOS production because tests showed the chemical had a strong tendency to accumulate in human tissue and could pose a health risk. Health activists suspect that PFOS causes cancer and liver damage, and increases the risk of high cholesterol, thyroid-related health problems, and the likelihood of attention deficit hyperactivity disorder (ADHD) in children, though the Centers for Disease Control has not yet found a link to these issues. Nevertheless, the company has since brought a non-PFOS version of its product back on the market, one with a chemical half-life of weeks instead of years.