What are PFASs, the toxic chemicals being found in drinking water?

More than 16 million Americans drink water contaminated with toxic chemicals that can be traced to military and industrial sites, according to new research from Harvard University.

The compounds in question are called poly- and perfluoroalkyl substances, or PFASs. They are typically used in fire retardants, oil and water repellents, furniture, waterproof clothes, take out containers and non-stick cookware. The study, published Tuesday in Environmental Science and Technology Letters, looked at more than 36,000 drinking water samples from 4,864 public water sources collected by the Environmental Protection Agency between 2013 and 2015. They found PFASs in water systems that serve more than 16 million people across 33 states, three American territories and the Salt River Pima-Maricopa Indian Community.