What Are PFAS 'Forever Chemicals' and Why They Matter
PFAS are a class of over 10,000 man-made chemicals that resist breakdown in the body and environment, linked to cancer, hormone disruption, and — according to new research — weakened bones in developing children.
The Chemical Bond That Won't Break
Somewhere in your bloodstream right now, there is almost certainly a trace of a chemical that was never supposed to be there. Per- and polyfluoroalkyl substances — known as PFAS, and nicknamed forever chemicals — are a family of more than 10,000 synthetic compounds that share one defining trait: an extraordinarily strong bond between carbon and fluorine atoms. That bond, among the most stable in all of chemistry, is precisely what makes these substances so useful — and so dangerous.
Because the carbon-fluorine bond resists heat, water, and most forms of chemical attack, PFAS do not break down in the natural environment. They accumulate in soil, leach into groundwater, travel up the food chain, and lodge in human tissue for years. Once in the body, they are only very slowly excreted. The result is a slow, invisible buildup that scientists call bioaccumulation.
Where PFAS Come From
PFAS were first synthesized in the 1940s and became commercially widespread by the 1950s. Their oil- and water-repelling properties made them ideal for a vast range of applications. They coat non-stick cookware, waterproof outdoor gear, stain-resistant carpets and upholstery, grease-proof food packaging (think microwave popcorn bags and fast-food wrappers), and the aqueous film-forming foam (AFFF) used to fight fuel fires at airports and military bases.
That last use is particularly significant. Decades of AFFF use at military installations and civilian airports has left heavy PFAS contamination in soil and groundwater at thousands of sites across the United States and Europe. A landmark US Geological Survey study found that at least 45% of the nation's tap water contains one or more types of PFAS, with contamination concentrated near urban areas, military sites, and industrial zones. Roughly 176 million Americans live in communities where drinking water has tested positive for these compounds.
How PFAS Affect the Body
Once ingested or inhaled, PFAS are absorbed into the bloodstream and tend to accumulate in the liver, kidneys, and blood serum. Their chemical stability means the body has no efficient way to neutralize or excrete them — some have half-lives in human tissue measured in years.
Research from the National Institute of Environmental Health Sciences and others has associated PFAS exposure with a growing list of health concerns:
- Cancer — kidney and testicular cancers are among the most consistently linked
- Endocrine disruption — PFAS can mimic or interfere with hormones, affecting thyroid function and metabolism
- Immune suppression — reduced vaccine response in children has been documented in multiple studies
- Liver and kidney disease — elevated liver enzymes and reduced kidney function are common findings
- Reproductive harm — including reduced fertility and complications during pregnancy
A Growing Threat to Children's Bones
Emerging research is adding skeletal development to the list of concerns. A study published in the Journal of the Endocrine Society followed 218 children from birth through age 12, measuring PFAS levels in blood at multiple points and assessing bone density at adolescence. The finding was striking: children with higher blood concentrations of perfluorooctanoic acid (PFOA) showed measurably lower forearm bone density — a difference associated with 10–30% higher odds of forearm fracture in childhood.
Lead researcher Dr. Jessie P. Buckley of the UNC Gillings School of Global Public Health noted that adolescence is a critical window for bone formation, and that PFAS exposure between ages 8 and 12 appeared to do more damage than earlier exposure — with girls showing stronger effects than boys. Since up to 90% of peak bone mass is established before age 18, any disruption during this window can raise the risk of osteoporosis decades later.
Regulation and What You Can Do
In 2024, the US Environmental Protection Agency established the first federal limits on several PFAS in drinking water, setting maximum levels for PFOA and PFOS at 4 parts per trillion — near the detection threshold. The European Union has moved toward a broad restriction on all non-essential uses of PFAS. Critics argue that regulation lags far behind the science, and that cleanup of contaminated sites will take decades.
Individuals can reduce exposure by filtering tap water with a certified reverse-osmosis or activated-carbon system, avoiding non-stick cookware with degraded coatings, and choosing food packaging labeled PFAS-free. Reducing consumption of fish caught near known contaminated sites also helps, as PFAS concentrate significantly in fatty fish tissue.
Why 'Forever' Matters
The defining challenge with PFAS is that their persistence means past exposure is never fully past. Chemicals released into the environment fifty years ago are still circulating in the bodies of people who were not yet born when they were manufactured. Cleaning up contaminated aquifers may take generations. This long shadow is why scientists and regulators increasingly treat PFAS not as a conventional pollutant to be managed, but as a systemic failure of chemical safety that demands sweeping reform — in manufacturing, in regulation, and in how society decides which chemicals are safe to release into the world in the first place.
