PFAS are a group of thousands of synthetic chemicals built around one of the strongest bonds in chemistry: the carbon-fluorine bond. That bond makes them extraordinarily resistant to heat, water, grease, and natural breakdown, which is why they earned the nickname “forever chemicals.” They’ve been manufactured since the 1940s and are now found in everything from nonstick pans to drinking water, and in the blood of nearly every person tested in the United States.
Why PFAS Don’t Break Down
The defining feature of PFAS is a chain of carbon atoms surrounded by fluorine atoms. The carbon-fluorine bond is one of the strongest chemical bonds known, and when multiple fluorine atoms cluster together on a molecule, they shield each other from the enzymes and microbes that normally decompose organic chemicals in soil and water. This isn’t just about raw bond strength. Billions of years of evolution have produced bacteria capable of breaking incredibly tough molecules, but very few natural organisms have ever encountered fluorinated carbon chains, so almost none have developed the tools to take them apart.
The practical result: once PFAS enter the environment, they persist for years to decades. They cycle through soil, groundwater, rivers, and oceans without meaningfully degrading. They accumulate in fish, wildlife, and human tissue. The same durability that makes them useful in products makes them nearly impossible to get rid of.
Where PFAS Show Up in Daily Life
PFAS chemicals are used in a surprisingly wide range of consumer products. The common thread is that they repel water, oil, or stains. You’ll find them in:
- Nonstick cookware, where they create the slippery coating on pans
- Stain-resistant carpets and rugs
- Water-repellent clothing, especially outdoor jackets and gear
- Food packaging, including grease-resistant wrappers and containers
- Personal care products like shampoo and cosmetics
- Cleaning products
- Ski and boat waxes and other products designed to reduce friction
One major historical source is firefighting foam, known as AFFF, which was used to extinguish large fuel fires at airports, military bases, and refineries. These foams have been a primary driver of groundwater contamination near the sites where they were used. Even some older home fire extinguishers labeled for flammable-liquid fires contained PFAS-based foam.
How You’re Exposed
Food is the dominant exposure route for most people. PFAS migrate into food from packaging, accumulate in seafood, and enter crops through contaminated water or soil. In a study of Norwegian women, food accounted for the majority of total PFAS intake, though indoor dust and air contributed up to roughly 50% in some cases.
Drinking water is the other major pathway. Near contaminated sites like military bases or industrial facilities, water can account for up to 75% of a person’s total PFAS exposure. Contamination has been detected in public water systems across the country, which prompted the EPA to set its first enforceable drinking water limits in 2024: a maximum of 4.0 parts per trillion each for PFOA and PFOS, the two most studied PFAS compounds. To put that in perspective, one part per trillion is roughly equivalent to a single drop in 20 Olympic swimming pools.
Health Effects Linked to PFAS
National health surveys show that PFAS are detectable in the blood of the vast majority of Americans. Data from 2017 to 2020 found that people at the 95th percentile of exposure had blood concentrations of about 3.6 nanograms per milliliter for PFOA and 14.8 nanograms per milliliter for PFOS. Those numbers have actually declined since the early 2000s as manufacturers phased out some older PFAS compounds, but exposure remains widespread because newer replacement chemicals are still in production.
Epidemiological evidence links PFAS exposure to several health concerns. The associations with the strongest support include increased cholesterol levels, changes in liver enzyme levels, reduced antibody response to certain vaccines (particularly in children receiving routine immunizations like diphtheria and tetanus), pregnancy complications including preeclampsia and high blood pressure, and small decreases in infant birth weight. PFOA specifically has been associated with kidney and testicular cancer.
The immune effects are worth understanding in practical terms. The U.S. National Academies of Sciences, Engineering and Medicine concluded in 2022 that the evidence is likely sufficient to say PFAS exposure reduces how well your body responds to vaccines. The clearest data comes from studies of children, where higher PFAS levels in blood corresponded to lower antibody production after standard childhood vaccinations. Results in adults have been less consistent and may depend on the specific vaccine studied.
Reducing PFAS in Your Water
If your drinking water contains PFAS, home filtration can help. EPA researchers tested commercially available systems and found that both reverse osmosis (RO) and granular activated carbon (GAC) filters reduced PFAS to below detectable levels under the right conditions. Some RO systems brought levels below 3 parts per trillion. Even under less ideal conditions, RO membranes removed more than 75% of individual PFAS compounds.
The catch is maintenance. RO systems require regular membrane and filter replacements to stay effective, and performance drops during intermittent use. Activated carbon filters also work well but need large quantities of carbon and sufficient contact time, especially for whole-house systems. A simple under-sink RO unit is generally the most practical option for filtering drinking and cooking water at home. Standard pitcher filters that use only basic carbon may reduce some PFAS but are less reliable for the full range of compounds.
What’s Replacing PFAS in Products
Manufacturers are gradually moving away from PFAS in food packaging and consumer goods, driven by regulation and consumer demand. The most promising replacements are bio-based materials: plant-derived waxes from sources like carnauba and candelilla that naturally repel water, modified cellulose fibers engineered to resist grease, and protein-based coatings. Plant waxes work by forming a crystalline barrier on the surface of paper or cardboard that blocks moisture and even slows the passage of oxygen.
Recycled paper treated with these bio-based coatings is increasingly common in food packaging. Unlike PFAS, these plant-derived materials break down through normal microbial and enzymatic processes in the environment. The transition is still underway, and not all “PFAS-free” labels guarantee a product uses safe alternatives, but the shift away from fluorinated coatings in food contact materials is accelerating across the industry.