Six Things to Know About ‘Forever Chemicals’

Almost half the tap water in the United States contains PFAS, a class of chemicals linked to serious health problems. On Wednesday, the Environmental Protection Agency announced that, for the first time, municipal utilities will have to detect and remove PFAS from drinking water.

Here’s what you need to know.

What are PFAS?

In 1938 a young chemist working on refrigerants for Dupont accidentally discovered a new compound that was remarkably resistant to water and grease, a finding that would lead to the creation of the Teflon brand of nonstick cookware.

Today there are nearly 15,000 per- and polyfluoroalkyl substances, which collectively go by the acronym PFAS, according to a database maintained by the E.P.A.

The common link is that they have a special bond of carbon and fluoride atoms, making them incredibly strong and resistant to heat, water, oil and dirt. For that reason, PFAS is used for everyday items as varied as microwave popcorn bags, water-repellent clothing and stain-resistant carpets. PFAS are also in firefighting foam, cosmetics, shampoos, toys and even dental floss.

Where are PFAS?

Everywhere, including drinking water. The indestructible nature that makes PFAS useful in some products also makes them harmful. The chemicals are virtually indestructible and do not fully degrade, accumulating in the environment and the human body.

The chemicals are so ubiquitous that they can be found in the blood of almost every person in the country. One recent government study detected PFAS chemicals in nearly half of the nation’s tap water. A global study of more than 45,000 water samples around the world found that about 31 percent of tested groundwater samples that weren’t near any obvious source of contamination had PFAS levels considered harmful to human health.