Perfluoroalkyl and polyfluoroalkyl chemicals, collectively known as PFAS, consist of more than 12,000 man-made chemical compounds that are used in a wide range of everyday products. These include take-out containers, drinking straws, outdoor clothing, medical devices, food packaging, cosmetics and most products advertised as being greaseproof, waterproof, flame retardant, or nonsticking. 

Despite being produced by manufacturers since the 1940s, PFAS are known to be damaging to the environment and to humans, leading to tighter government oversight regarding their use – especially in and around municipal water sources. 

Independent of this improved regulation, the chemicals can also often be at least partially avoided through conscientious consumer practices. 

What are 'forever' chemicals? 

PFAS are sometimes called "forever" chemicals because they have a carbon-fluorine bond – one of the strongest and most stable bonds in chemistry. "This bond means these chemicals don't degrade easily in the environment or in our bodies, which is why PFAS are known as 'forever' chemicals," explains Lauren Petrick, Ph.D., an environmental medicine and public health scientist at the Icahn School of Medicine at Mount Sinai.

And because these chemicals first started being used in industrial manufacturing more than eight decades ago, they've been able to make their way into many food and water sources, contaminating some animals that humans eat such as cattle grazing on PFAS-polluted grasses or fish swimming in PFAS-polluted water. 

"PFAS are now found in the air, water, and soil, so you can be exposed to the chemicals in many different ways," says Petrick.

More on this:What are PFAS? 'Forever chemicals' are common and dangerous.

Why are PFAS dangerous? 

This is concerning because high levels of PFAS are known to be toxic to humans, and the everlasting nature of these chemicals means they can build up in our systems over time, leading to potentially worrisome outcomes.

Some risk factors associated with PFAS exposure include "kidney cancer, high cholesterol, lower immune response to vaccination among children, and some pregnancy complications," says Scott Bartell, PhD, a professor of environmental and occupational health at the University of California, Irvine.

Investigation:Hundreds of drinking water systems exceed new PFAS standards. It could grow to thousands.

The Centers for Disease Control and Prevention notes that significant exposure to PFAS may also affect growth and development in some people and could negatively impact thyroid and liver function. 

DeLisa Fairweather, Ph,.D., vice chair of translational research for the department of cardiovascular medicine at Mayo Clinic and a former toxicologist in the department of environmental health sciences at Johns Hopkins University, also warns of increased risk of obesity related to PFAS exposure and potential complications associated with regulation and distribution of hormones throughout the body.  

How to avoid PFAS

Though most people would love to steer clear of any such issues, avoiding PFAS isn't easy as they are present in many everyday products, including many food and water sources. In fact, research shows that PFAS are present in as much as 45% of water supplies across the United States, meaning PFAS may be flowing into the homes of millions of Americans.

This is why the first step toward avoiding PFAS, Petrick advises, should be installing or using a water purification system that's capable of filtering out the toxic chemicals. 

It may also be wise to avoid beauty or cookware products that are advertised as being waterproof, greaseproof, or nonsticking if they aren't specifically labeled as PFAS-free. "To limit exposure, I suggest using metal or glass containers to carry and prepare water and food," advises Fairweather. She also recommends against drinking out of plastic straws, using takeaway food containers, "or purchasing carpet and soft furniture that has been treated to become waterproof or to retard fires."