PFAS have been making headlines again this month after the Environmental Protection Agency (EPA) announced newly established regulations limiting the amount of these toxic chemicals that can be used in or around municipal water sources. It's a move that environmental scientists have been seeking for decades, but is just one of many they say are still needed.

"The general public shouldn’t be responsible for removing their PFAS exposure as the chemicals were released into the environment by chemical companies in the first place," says Dr. Erin Haynes, a professor of preventive medicine and environmental health at the University of Kentucky College of Public Health. Instead, she says the burden to protect citizens from PFAS exposure rests on companies and on government oversight and regulation. 

What are PFAS? 

Perfluoroalkyl and polyfluoroalkyl chemicals, collectively known as PFAS, consist of more than 12,000 man-made chemical compounds that are "used in a broad array of consumer products," explains Susie Dai, PhD, an environmental scientist at Texas A&M University. 

Most commonly, PFAS are used in non-stick, greaseproof and waterproof coatings and surfaces, and are also used in flame retardants and to extend the life or usefulness of a variety of everyday items. 

Are PFAS the same as "forever" chemicals?

While different PFAS have different chemical structures, all PFAS have at least one common trait: the presence of carbon-fluorine bonds, which are among the strongest bonds in chemistry. 

This powerful bond is attractive to manufacturers because it extends the life and improves the functionality of many common products; but it's also a bad thing because it means that once these chemicals are created and released into the world, they don't break down easily in the environment or in our bodies - earning PFAS the nickname "forever chemicals."

Over time, this exposure can do harm to the planet and to people and animals. "Exposure to high levels of PFAS is associated with higher risk of cancer, impaired kidney and liver function, reproduction and embryonic development issues, and blunted responses to vaccines," says Dr. Kristin Scheible, a microbiologist and immunologist at the University of Rochester Medical Center. 

How are people exposed to PFAS?

While avoiding exposure is difficult since PFAS have been used in manufacturing for more than 80 years and have found their way into countless soil and water sources during that time, it's possible to at least limit some exposure by knowing which products and places PFAS are commonly found in. 

More:Prime energy, sports drinks contain PFAS and excessive caffeine, class action suits say

For instance, PFAS are commonly used in non-stick cookware, greaseproof food packaging, outdoor clothing, waterproof cosmetics, and stain-resistant carpets and furniture. While most such products don't advertise that they were made using PFAS, if a product says it's waterproof, stain proof, or non-sticking, and isn't advertised as being PFAS-free, "then it likely contains PFAS," says Scott Bartell, PhD, a professor of environmental and occupational health at the University of California, Irvine.

Beyond commercial product use, people are also exposed to PFAS by eating produce that has been grown in PFAS-contaminated soil or by eating animals that have fed on PFAS-contaminated grasses. More commonly, many people drink directly from PFAS-contaminated water sources as research shows that as much as 45% of tap water in America has become contaminated by at least one of these forever chemicals.

To help, Bartell recommends installing a water purification system for any tap water that enters the home so PFAS can be filtered out, "until the new EPA standards begin to take effect."