“Forever chemicals” is the common name for a group of manufactured compounds called PFAS, short for per- and polyfluoroalkyl substances. There are more than 12,000 individual PFAS compounds, and they earned the nickname because they resist virtually every form of natural breakdown: heat, sunlight, water, and microbial digestion. Once released into the environment, they persist for decades or longer, accumulating in soil, water, wildlife, and human blood.
Why PFAS Don’t Break Down
The defining feature of every PFAS molecule is a chain of carbon atoms bonded to fluorine atoms. The carbon-fluorine bond is one of the strongest chemical bonds known. When multiple fluorine atoms attach to the same carbon, each bond actually becomes stronger than it would be alone, making the molecule even more resistant to breaking apart. Biological enzymes, the tools that bacteria and other organisms use to dismantle organic molecules, simply aren’t equipped to crack these bonds efficiently.
This resilience is exactly what made PFAS attractive to manufacturers starting in the 1940s. The same chemistry that makes them indestructible in nature made them ideal for products that needed to repel water, grease, and heat. The problem is that “indestructible in nature” also means they never go away.
Where You Encounter PFAS
PFAS show up in a surprisingly wide range of everyday products. Their non-stick and grease-resistant properties made them standard ingredients in nonstick cookware coatings, fast-food wrappers, microwave popcorn bags, takeout containers, and pet food bags. They’re also found in stain-resistant fabrics, waterproof outdoor clothing, some cosmetics, and firefighting foams used at airports and military bases.
Of these sources, the U.S. Food and Drug Administration has identified grease-proof coatings on paper food packaging as the primary dietary exposure route. A voluntary industry phase-out of these particular coatings has been completed, but older products and environmental contamination remain. Drinking water is the other major route: PFAS from industrial discharge, landfills, and firefighting foam leach into groundwater and surface water supplies, sometimes at levels far above what regulators consider safe.
How PFAS Build Up in the Body
Unlike most environmental pollutants, PFAS don’t dissolve in fat. Instead, they bind to proteins in your blood, liver, kidneys, and brain tissue. This protein-binding behavior means they circulate in your bloodstream for years before your body can slowly eliminate them. In a study of 106 people who stopped drinking PFAS-contaminated water, the average time it took for blood levels to drop by half was 2.7 years for PFOA, 3.4 years for PFOS, and 5.3 years for PFHxS. That means even after you eliminate the source of exposure, it can take a decade or more for your levels to drop substantially.
If you want to know your own levels, PFAS blood testing is available through commercial clinical laboratories. Your doctor can order the test, and results reflect a combination of recent and past exposures given those long half-lives.
Health Risks Linked to PFAS
Research on PFAS health effects has focused heavily on PFOA and PFOS, the two most studied compounds. Exposure has been linked to kidney and testicular cancers, decreased fertility, hormone disruption, and liver disease. The immune system effects are particularly well documented: the strongest evidence shows that PFAS exposure reduces the body’s ability to produce antibodies after vaccination, especially in children receiving tetanus and diphtheria vaccines. More recently, one PFAS compound was associated with reduced antibody levels in pregnant women following SARS-CoV-2 infection.
These health effects have been observed at very low concentrations, which is part of what makes PFAS so concerning. The compounds don’t need to be present in large amounts to interfere with biological systems over time.
How PFAS Move Through the Food Chain
PFAS have been detected in environmental samples from every continent, including the Arctic and Antarctic. In wildlife, these chemicals biomagnify, meaning their concentration increases as you move up the food chain. The effect is most dramatic in food chains that include air-breathing animals like birds and marine mammals. In the Canadian Arctic, PFOS concentrations in beluga whales were roughly 25 times higher than in the cod they eat. Polar bears showed levels about 20 times higher than those in ringed seals.
For humans, this means that eating fish, shellfish, or game from contaminated areas can be a significant exposure route on top of drinking water and consumer products.
U.S. Drinking Water Limits
In April 2024, the EPA finalized the first legally enforceable limits for PFAS in drinking water. The maximum contaminant levels are strict, measured in parts per trillion:
- PFOA: 4.0 parts per trillion
- PFOS: 4.0 parts per trillion
- PFHxS: 10 parts per trillion
- PFNA: 10 parts per trillion
- HFPO-DA (GenX): 10 parts per trillion
For PFOA and PFOS, the EPA set the health-based goal at zero, acknowledging that no level of exposure is considered safe. The enforceable limit of 4 parts per trillion reflects the lowest level that water systems can reliably measure and treat. When two or more of the other regulated PFAS appear together, utilities must meet a combined hazard index that accounts for their additive effects.
Reducing Your Exposure at Home
Home water filtration is one of the most practical steps you can take. Not all filters perform equally, though. Testing by North Carolina State University found that reverse osmosis systems remove 94 to 99% of long-chain PFAS and 75 to 99% of short-chain PFAS. Activated carbon filters, including the kind built into refrigerators, are less effective: they removed 56 to 78% of long-chain PFAS but only 29 to 65% of the harder-to-capture short-chain varieties.
Beyond water, you can limit exposure by avoiding nonstick cookware with damaged coatings, choosing uncoated paper food containers when possible, and checking whether stain-resistant treatments on furniture or clothing contain PFAS. These steps won’t eliminate exposure entirely since PFAS are so widespread, but they reduce the ongoing daily dose your body has to process.
Regulatory Efforts to Phase Out PFAS
The European Union is pursuing what would be the world’s broadest restriction on PFAS. The European Chemicals Agency published an updated restriction proposal in August 2025 and is currently evaluating its scope and timeline. If adopted, the restriction would cover essentially all PFAS uses across consumer and industrial products, with limited exemptions for applications where no alternatives exist yet.
In the U.S., the approach has been more targeted. The new drinking water standards give public water systems until 2029 to comply, and the EPA continues to add individual PFAS compounds to its regulatory frameworks. Several U.S. states have moved faster than the federal government, banning PFAS in food packaging, cosmetics, and firefighting foam. The overall direction is clear: the era of unrestricted PFAS use is ending, but the chemicals already released into the environment will be with us for generations.