PFAS

Based on Wikipedia: PFAS

In 2018, a Washington Post article coined a phrase that would stick: "forever chemicals." The name is grimly accurate. These synthetic compounds, once they enter your body or the environment, essentially never leave. They accumulate in your blood, lodge in your liver, seep into groundwater, fall in rain, and concentrate up the food chain until apex predators—including humans—carry concentrations thousands of times higher than the water around them.

The chemicals in question are called per- and polyfluoroalkyl substances, or PFAS for short. There are millions of them—quite literally. PubChem, the database of chemical compounds, lists seven million distinct PFAS chemicals. The United States Environmental Protection Agency's toxicity database counts nearly fifteen thousand. The exact number depends on how you define the category, which different organizations do differently, but the core feature is always the same: a chain of carbon atoms studded with fluorine.

That carbon-fluorine bond is the key to everything—both why these chemicals are so useful and why they're so dangerous.

The Perfect Chemical

The carbon-fluorine bond is one of the strongest in organic chemistry. It's remarkably stable, resistant to heat, impervious to water, and unfazed by oil or grease. This makes PFAS extraordinarily useful for creating surfaces that nothing can stick to.

The story begins in 1938 with the invention of Teflon—polytetrafluoroethylene, if you want the full name—which remains the most famous member of the PFAS family. A chemist at DuPont stumbled upon it accidentally while working with refrigerant gases. The slippery white powder that resulted would eventually coat billions of frying pans, giving home cooks the ability to flip eggs without butter and clean up with a quick wipe.

But Teflon was just the beginning.

Today, PFAS appear in an astonishing range of products. Waterproof fabric. Yoga pants. Carpets. Shampoo. Mobile phone screens. Wall paint. Furniture. Adhesives. Food packaging. Firefighting foam. Electrical wire insulation. Lipstick. Eyeliner. Mascara. Foundation. Concealer. Lip balm. Blush. Nail polish. Even feminine hygiene products.

The market for these chemicals reached an estimated twenty-eight billion dollars in 2023. Just twelve companies produce the majority of them, including household names like 3M, BASF, Bayer, and Honeywell. At roughly twenty dollars per kilogram, the industry generates about four billion dollars in annual profit—a comfortable sixteen percent margin.

For decades, PFAS seemed like a triumph of chemistry. Stain-resistant carpets that laughed off red wine spills. Raincoats that kept you bone-dry in downpours. Firefighting foam that smothered flames faster than anything else. The chemistry was so effective that manufacturers kept finding new applications.

There was just one problem.

The Forever Part

The same carbon-fluorine bond that makes PFAS so useful also makes them nearly indestructible. Most organic molecules eventually break down—bacteria consume them, sunlight degrades them, chemical reactions transform them into something else. But the carbon-fluorine bond resists all of this.

Some PFAS have half-lives of over eight years in the human body. That means if you absorb a certain amount today, half of it will still be circulating in your bloodstream nearly a decade from now. And you're absorbing more every day.

These chemicals don't just persist in individuals. They persist everywhere.

Scientists once assumed that PFAS would eventually accumulate in the oceans, where they'd be diluted to harmless concentrations over decades. A 2021 study from Stockholm University shattered that assumption. Researchers found that when waves hit coastlines, PFAS transfer from water to air, becoming airborne pollutants that eventually fall as rain. The cycle is essentially endless.

In 2022, researchers measuring perfluoroalkyl acids—a common subgroup of PFAS—in rainwater around the world made a disturbing discovery. Levels of at least four of these compounds exceeded the EPA's lifetime drinking water health advisories, as well as comparable European safety standards. The researchers concluded that "the planetary boundary for chemical pollution" had been exceeded. In other words, there's nowhere left on Earth where rain is truly clean.

A 2024 study of forty-five thousand groundwater samples worldwide found that thirty-one percent contained PFAS levels harmful to human health—and these samples came from areas with no obvious nearby source of contamination. The chemicals have been found in Antarctica. They've been found in the blood of polar bears and the tissue of Arctic seals. They're in the coffee you drink, the rice you eat, and the meat from animals raised on contaminated ground.

Climbing the Food Chain

When scientists study how pollutants move through ecosystems, they distinguish between two related concepts. Bioaccumulation describes how a chemical builds up within an individual organism over its lifetime. Biomagnification describes how concentrations increase as you move up the food chain—small fish absorb chemicals from the water, bigger fish eat many small fish and concentrate those chemicals further, and the predators at the top end up with the highest levels of all.

PFAS exhibit both phenomena dramatically.

The numbers are striking. In some studies, PFAS concentrations in fish and wildlife exceed five thousand times the levels found in the surrounding water. A study in France's Gironde estuary found trophic magnification factors—the measure of how much concentrations increase per level of the food chain—of six for one common PFAS compound and over three for another. Each step up the food chain multiplies the concentration.

A 2023 analysis of five hundred fish fillet samples collected across the United States found that freshwater fish universally contain high levels of harmful PFAS. A single serving of freshwater fish can significantly increase the PFAS concentration in your blood.

For populations that rely heavily on wild-caught fish and shellfish—including many Indigenous communities—the implications are severe. Some fisheries have been closed entirely. Others operate under strict catch limits. The contamination has disrupted food supplies and traditional ways of life.

There's even an unexpected vector: migratory birds. Species that spend winters in polluted southern waters carry PFAS north to the Arctic, where they become prey for local predators. As Rainer Lohmann, an oceanographer at the University of Rhode Island, noted, this creates devastating localized effects. Arctic predators already accumulate toxins in their bodies; the additional PFAS load from contaminated migratory birds enters their food chain directly.

What These Chemicals Do to Bodies

For years, PFAS were considered chemically inert—meaning they wouldn't react with biological systems. Early studies of industrial workers who handled these chemicals daily found elevated blood levels but reported no obvious health effects. The compounds just seemed to sit there, doing nothing.

That conclusion was wrong.

The most comprehensive health research came from a legal settlement. In the mid-2000s, communities in the Ohio River Valley sued DuPont over contamination from its Washington Works plant. As part of the settlement, three epidemiologists formed what became known as the C8 Science Panel—named after PFOA, which has eight carbon atoms—and spent nearly a decade studying the health of sixty-nine thousand people living near the plant.

What they found was alarming. The average PFOA concentration in local residents' blood was eighty-three nanograms per milliliter. The national average was four. These people had more than twenty times the typical exposure.

The panel established "probable links"—a legal and scientific term indicating strong evidence of causation—between elevated PFOA levels and six conditions: high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer, and pregnancy-induced hypertension including preeclampsia.

Subsequent research has expanded the list. PFAS exposure is now linked to decreased fertility, fetal and child developmental issues, obesity, decreased immunity and suboptimal antibody response, and various cancers. Some PFAS are classified as carcinogens. Others are endocrine disruptors—chemicals that interfere with hormone systems.

Pregnant women face particular risks. PFAS exposure is a risk factor for hypertensive disorders during pregnancy. The chemicals can transfer from mother to infant through breast milk. Even the personal care products pregnant women use—nail polish, fragrances, makeup, hair dye, hair spray—are associated with elevated PFAS levels, because so many of these products contain the compounds.

The severity of health effects varies with the length and level of exposure, as well as individual health status. But given that virtually everyone on Earth now carries some PFAS in their blood, the question isn't whether you're exposed—it's how much.

What the Companies Knew

Internal documents revealed through litigation tell a damning story. Studies have shown that companies knew about the health dangers of PFAS as early as the 1970s. DuPont and 3M were aware that these chemicals were, in their own words, "highly toxic when inhaled and moderately toxic when ingested."

They kept making them anyway.

They kept selling them anyway.

The lawsuits have been enormous. In 2023, 3M agreed to pay 10.3 billion dollars to settle claims over water contamination—the largest PFAS settlement to date. Other manufacturers have paid billions more. The litigation continues.

The True Cost

Industry profits from PFAS run about four billion dollars annually. The costs they've externalized onto society run considerably higher.

ChemSec, a Swedish nonprofit focused on toxic chemicals, estimates that the external costs of PFAS—including soil and water remediation, treatment of related diseases, and pollution monitoring—may reach 17.5 trillion dollars annually. That's not a typo. Trillion, with a T.

The Nordic Council of Ministers estimated that health costs alone in the European Economic Area run between fifty-two and eighty-four billion euros. In the United States, disease costs attributable to PFAS are estimated at six to sixty-two billion dollars—a wide range reflecting uncertainty about how many conditions are actually caused by these exposures.

In January 2025, estimates for cleaning up PFAS contamination in the United Kingdom and Europe came to 1.6 trillion pounds over twenty years—about eighty-four billion pounds annually. Just for cleanup. Just in Europe.

Compare that to the industry's four billion dollars in annual profit, and a clear picture emerges: the companies that made and sold these chemicals captured the gains while distributing the losses across society at large. Economists call this an externality. Regular people might call it something else.

Regulation and Resistance

International regulation of PFAS began in 2009 under the Stockholm Convention on Persistent Organic Pollutants, an international treaty designed to eliminate the worst chemical offenders. Some jurisdictions have gone further—the European Union and China are planning additional reductions and phase-outs.

But the major producers and users haven't all signed on. The United States, Israel, and Malaysia have not ratified the Stockholm Convention. The chemical industry has lobbied governments aggressively to reduce regulations.

This creates a patchwork world. In some countries, certain PFAS are banned or restricted. In others, they remain freely available. The chemicals themselves, of course, don't respect borders. They flow through groundwater, rise into clouds, and fall as rain wherever the weather takes them.

Some progress has come from market pressure rather than regulation. Several companies have announced plans to end production or use of PFAS, responding to consumer concerns and legal liability rather than legal requirements. But the transition is slow, and replacement chemicals—often shorter-chain PFAS variants—may pose their own risks.

The shorter-chain compounds were initially promoted as safer alternatives because they don't accumulate as readily in mammals. Recent research has tempered that optimism. While they may be less prone to bioaccumulation, they're still persistent, still potentially harmful, and still ending up everywhere.

The Chemistry Beneath

Understanding why PFAS behave as they do requires a bit of chemistry—nothing too complex, but the basics matter.

Fluorine is the most electronegative element on the periodic table. Electronegativity is a measure of how strongly an atom attracts electrons toward itself. When fluorine bonds with carbon, it grips those shared electrons tightly, creating an extremely stable molecular structure.

This stability is why nothing can break these bonds easily—not heat, not water, not oils, not the enzymes in your liver that normally metabolize foreign compounds. The biological machinery that evolved to break down organic molecules simply can't get a grip on the carbon-fluorine bond.

The same electronegativity that makes fluorine so grippy also makes PFAS molecules somewhat unusual in another way. Most organic compounds are either hydrophobic—repelling water—or lipophilic—attracted to fats and oils. PFAS are both hydrophobic and lipophobic. They repel water and they repel oil. This is why they're so useful for creating surfaces that nothing sticks to, but it's also why they behave strangely in biological systems.

Instead of dissolving in fats like most organic pollutants, PFAS tend to bind to proteins. They accumulate in the blood and liver rather than in fatty tissue. This makes them harder to excrete and easier to pass along—through breast milk, for instance, or from prey to predator.

The fluorinated surfaces of these molecules also experience reduced London dispersion forces—the weak attractions between all molecules that result from temporary fluctuations in their electron clouds. With fewer of these attractions, PFAS don't interact strongly with other substances. They slip through biological membranes, pass through soil, and move readily through water.

In short, the same properties that make PFAS so useful in products make them so dangerous in the environment. They're slippery in every sense.

The Ubiquitous Acid

Among all the PFAS compounds, one deserves special attention: trifluoroacetic acid, abbreviated TFA. It's the most common PFAS found in the environment.

TFA is everywhere. It's in aquatic ecosystems around the world, where it persists and accumulates to ever-increasing concentrations. Unlike some PFAS that were manufactured intentionally, TFA often appears as a breakdown product of other chemicals—including certain pesticides like fluazinam and flufenacet.

The ubiquity of TFA illustrates a broader challenge. Even if manufacturers stopped producing PFAS tomorrow, the chemicals already in the environment would persist for decades or centuries. And every day, more TFA enters the environment as other fluorinated compounds degrade.

The planetary contamination is, in a very real sense, irreversible on any human timescale.

What Happens Now

Cleaning up PFAS contamination is extraordinarily difficult and expensive. The same stability that makes these chemicals persistent makes them hard to destroy. Standard water treatment doesn't remove them. Standard soil remediation doesn't break them down. Specialized technologies exist—granular activated carbon filtration, ion exchange resins, high-temperature incineration—but they're costly and not always effective.

The 1.6 trillion pounds estimated for cleanup in Europe over twenty years isn't a ceiling—it's a current estimate that could grow as more contamination is discovered and as cleanup standards tighten.

Meanwhile, production continues. Sales continue. New PFAS enter the environment every day.

The story of PFAS is, in many ways, a parable about modern industrial chemistry. Remarkable compounds that made life easier and products better turned out to have costs that weren't apparent for decades—costs that accumulated invisibly in blood and groundwater and rain until they became impossible to ignore.

The chefs who switched away from Teflon pans, the consumers who started checking labels for PFAS-free products, the communities who sued over contaminated water—they're all responding to the same realization. Some conveniences come with hidden prices. Some chemicals, once released, never really go away.

Forever is a long time.