Perfluorinated chemicals (PFCs) have been produced since the 1950s. They have many applications, including as protective coatings for fabrics, carpet and paper to repel water and oil. In the late 1990’s, the United States Environmental Protection Agency (U.S. EPA) received information indicating that perfluorooctane sulfonate (PFOS) was widespread in the blood of the general U.S. population and in the environment, and presented concerns for persistence, bioaccumulation and toxicity. Following discussions between U.S. EPA and 3M, the sole U.S. manufacturer of PFOS, the company terminated production of perfluoroalkyl sulfonate (PFAS), the class of chemicals to which PFOS belongs. Following the voluntary phase-out, the U.S. EPA issued regulations to restrict the reintroduction of perfluoroalkyl sulfonate into the U.S. market, with final rules to limit any future manufacture or importation of these chemicals published in 2002 and 2007. In the mean time, another perfluorinated chemical, perfluorooctanoic acid (PFOA) was also found to pose similar concerns.