Forever Chemicals

The story starts in New Jersey, in 1938. A young DuPont chemist named Roy Plunkett was working on new refrigerant gases. One morning he opened the valve on a cylinder of one of them, and nothing came out. The cylinder should have been full, so he cut it open and found the inside coated with a strange, slippery white powder.

The gas molecules had linked up into long chains, creating a material unlike anything anyone had seen. Almost nothing stuck to it. Acids couldn’t eat it. Heat barely bothered it. During World War II it even sealed equipment in the Manhattan Project that handled some of the most corrosive chemicals ever made.

After the war, DuPont gave it a catchier name: Teflon. By the early 1960s it was coating frying pans in American kitchens, and it got so famous for being slippery that in 1983 a congresswoman called President Reagan “the Teflon president,” because no scandal ever seemed to stick to him.

Meanwhile in Minnesota, 3M was cooking up its own fluorine chemistry. In 1953, a few drops of an experimental compound splashed onto a lab assistant’s canvas sneaker and wouldn’t wash off. Chemist Patsy Sherman noticed that water and oil wouldn’t stick to that spot either. That accident became Scotchgard.

3M also sold DuPont a key ingredient for making Teflon: a chemical called PFOA, nicknamed C8 for its chain of eight carbon atoms. And in the 1960s, the U.S. Navy and 3M developed a firefighting foam that could smother fuel fires in seconds. It saved lives, and for decades it was sprayed in training drills at military bases and airports.

From there, the family exploded:

Together they’re called per- and polyfluoroalkyl substances. And they all share one secret weapon. Before we get to it, here’s the whole story at a glance: the miracle, the harm, and the rules, running side by side.

To see the secret weapon, zoom way, way in. This is PFOA. It’s built on a backbone of carbon atoms, and every one of those carbons is wrapped in fluorine.

Fluorine is the most electronegative element on the periodic table. Basically, it’s the greediest atom there is when it comes to electrons. When it bonds to carbon, it pulls their shared electrons in tight, forming the strongest single bond in organic chemistry.

And because the fluorine atoms are packed all the way around the chain, they form a kind of armor. Anything that might attack the carbon backbone just can’t get a grip. Bacteria that break down almost everything else can’t digest it. Sunlight barely touches it. Water, acids and heat? It shrugs them off.

That toughness is exactly what made PFAS so valuable. And it’s exactly what makes them a problem.

Superpower number two

That fluorine-coated tail doesn’t like water. But unlike most chemicals, it doesn’t like oil or grease either. So when you coat a surface with it, water beads up, oil beads up, and food slides right off.

Many PFAS also have a head that loves water. That makes them surfactants: molecules that crowd together at the surface of a liquid. In firefighting foam, they help spread a thin film across burning fuel, sealing it off from the air. That’s why the foam worked so well. And it’s how so much PFAS ended up soaking into the ground.

Why “forever”

Now put it all together: a molecule nature can’t break down, that dissolves in water, and that travels easily. Once PFAS get into the environment, they don’t go away. They just move: from soil into groundwater, from rivers to the ocean, and even up into the air and back down as rain.

Inside your body, many PFAS don’t settle into fat the way a lot of other pollutants do. They latch onto proteins in your blood and build up in organs like the liver and kidneys. Your kidneys even pull some of them back into your blood instead of flushing them out. For PFOS, one of the most common, it takes years for your body to get rid of just half of it.

So how did these chemicals get from factories into almost everyone’s blood? A lot of it came through water. Factories released PFAS into rivers and the air. Firefighting foam soaked into the ground at military bases and airports. Landfills full of PFAS-treated products leaked. And wastewater plants, which were never designed to remove them, passed them right through.

One town’s story

To see how this played out for one community, go to Parkersburg, West Virginia, on the Ohio River.

Not just Parkersburg

This was never just a Parkersburg problem. In 1997, a 3M scientist tested blood samples from blood banks around the country and found PFOS in every single one. When the CDC started measuring PFAS in its national health survey, it found them in the blood of nearly everyone it tested: adults and kids, all across the country.

We take them in from many directions: drinking water, food like fish, food packaging, household dust, and the products around us. Firefighters and factory workers can get much higher doses. PFAS can also pass from mother to baby, across the placenta and through breast milk. Even so, health experts still say the benefits of breastfeeding outweigh the risks.

But here’s some genuinely good news. After U.S. manufacturers phased out PFOS and PFOA, levels in Americans’ blood dropped dramatically.

So what do PFAS actually do to us? In 2022, the National Academies of Sciences, Engineering, and Medicine reviewed decades of research. They sorted the health effects by how strong the evidence is: four with sufficient evidence, and more with limited evidence.

In 2023, the World Health Organization’s cancer agency classified PFOA as carcinogenic to humans, its highest category. And the EPA concluded that PFOA and PFOS are likely carcinogens, setting the health goal for both at zero.

Now, exposure isn’t the same as getting sick. Risk depends on how much you’re exposed to, and for how long. Most people have low levels. But near contaminated sites, levels can be many times higher. That’s why the National Academies recommend that doctors offer PFAS blood testing to people who are likely to have high exposure.

For decades, there were no national limits on PFAS in drinking water, just non-binding health advisories. That changed in April 2024, when the EPA set the first enforceable national limits.

PFOA and PFOS were capped at four parts per trillion. Three more, PFHxS, PFNA and GenX, were limited to ten parts per trillion. And a fourth limit covered mixtures that can add up together.

Then the plan changed, and it’s still changing. The board below walks through each turn, and where things stand as of October 2026.

The mixture limit, by the numbers

The fourth limit is the least intuitive. It covers PFHxS, PFNA, GenX and a fourth chemical, PFBS. Each one’s level is divided by a health-based number, and the shares are added up into a hazard index. If the total tops 1, the water is over the limit, even if every chemical is under its own.

Utilities warn that cleanup is expensive, and those costs land on water bills. Health advocates warn that every delay means more years of exposure. Both concerns are real.

And many states aren’t waiting. Several have set their own drinking water limits. Minnesota now bans PFAS added on purpose to products like cookware, carpets, cosmetics and dental floss. And in Europe, new limits on PFAS in drinking water took effect in January 2026.

So, what can you do? Quite a lot, actually. Here are four steps. Tick them off as you go.

Here’s the strange twist in the PFAS story. The very thing that made these chemicals a miracle, their strength, is what makes them so hard to get rid of.

But the story isn’t over. Scientists are developing ways to destroy PFAS, using intense heat, electricity, and even chemistry that breaks some of them apart at temperatures not much hotter than boiling water.

Blood levels of the oldest PFAS are falling. And the more people know, the faster that progress can go. So check your water, choose your filter wisely, and share this with someone who drinks water. Which is, you know, everyone.