In 1929 in Chicago, people kept mysteriously dying inside their homes.

It took 15 deaths for the authorities to realize that these people were getting killed by... their fridges

because fridges back then were no longer just boxes of ice. Instead, they relied on a chemical looping through the back to stay cold.

And the best chemical for the job was methyl chloride, a toxic and virtually odorless gas.

So if it somehow leaked from the fridge, it could kill you without warning.

Other fridges used flammable gases instead, so a leak combined with a spark from the stove, and your house could suddenly go up in flames.

So one company tried to solve this problem, but in the process, they accidentally created a seemingly magical substance.

Soon, it made its way into a huge range of products, which were so popular they ended up in nearly every home in America.

But what people didn't know was that these products came at a price.

The chemicals used to make them were being released into the environment, slowly poisoning everyone on the planet, including me.

- You have high levels of a chemical you never heard of.

- It shocks me. Like, where could this have come from?

- Almost every living creature, from polar bears to birds to fish, massive worldwide contamination by completely manmade chemicals that are fingerprints back to just a couple of companies.

- This is a video about one of the biggest chemical coverups in history.

For legal reasons, I want to note that this investigation is based on publicly available documents, recordings, and third-party opinions.

All sources are linked in the description.

The story all began with an attempt to save lives.

In 1936, a chemical company called DuPont set out to find a safer alternative to the gases used in fridges, one that was neither toxic nor flammable.

Their lead scientist on the project was a 27-year-old chemist named Roy J. Plunkett.

He was experimenting with a gas called tetrafluoroethylene, or TFE.

It's a pair of double-bonded carbons, each bonded to two fluorine atoms.

One morning, as Plunkett was setting up a test, his assistant picked out a cylinder full of TFE and twisted the valve, but nothing came out.

Plunkett thought the gas must have leaked, but the cylinder still weighed about as much as a full one, so he grabbed a saw and cut the cylinder in half.

Inside, he was shocked to see it was full of a white, slippery powder.

So what happened to the gas?

Well, what the chemist reasoned was that under the high pressure of the cylinder, one of the double bonds between the carbons in TFE must have broken.

And now those two carbon atoms each had a bonding site free.

So one of them probably grabbed onto a carbon from a different TFE molecule, breaking its double bond.

And then that molecule did the same, and the process repeated again and again until all of the TFE was trapped in these long chains.

The gas had polymerized into polytetrafluoroethylene, forming this slippery powder.

Plunkett just wanted to get rid of it because it ruined his experiment.

But before throwing it out, he decided to do some tests on it.

So he tried pouring water on it, but the water just beaded off.

So he tried acid. Again, nothing happened.

Then he tried the strongest base he had, but that wouldn't melt it either.

Plunkett went through all of the solvents in the lab, but the powder remained intact.

It wouldn't melt, corrode, or react with anything.

It was seemingly indestructible.

The reason it was so indestructible was because of this bond, the carbon-fluorine bond.

See, out of all of the elements, fluorine is the greediest, the most electron-hungry atom.

Its outer shell is a single electron away from being complete, which would make it perfectly stable.

So fluorine really, really wants that electron.

And because it's so small compared to most other elements, the protons in its nucleus can get close to the electrons of other atoms.

And because of their positive charge, they pull on them really hard.

So near a carbon atom, fluorine grabs onto one of the carbon's electrons to complete its outer shell, and this keeps the two atoms bonded together.

But the fluorine isn't done there.

It keeps tugging on the carbon's electrons, pulling them closer to itself, which makes fluorine slightly negatively charged and the carbon slightly positive.

So now there's an electrostatic attraction that makes this bond even stronger.

Now, in reality, electrons behave more like fuzzy clouds than the orbiting points in this animation, but the principle still holds.

In terms of energy, this is actually the strongest single bond a carbon can form.

So if other atoms or molecules get close, they're essentially ignored.

And Plunkett's magic powder was completely covered in carbon-fluorine bonds, so it hardly reacted with anything.

Okay, so he is got this incredibly inert stuff.

Was he really trying to get rid of it?

- He actually didn't know what to do with it 'cause like what do you do with the material that doesn't, you know, react with anything?

But luckily his employer, DuPont, they were actually working with the US Army on the Manhattan Project.

So they were refining uranium and plutonium 'cause of course there's a World War II reference in a Veritasium video. You just have to have it.

- To get the fuel for nuclear bombs, enriched uranium, you first have to turn the uranium into a gas, uranium hexafluoride.

It was a nasty chemical that corroded everything.

So all the gaskets, seals, and miles of pipe in the plant at Oak Ridge had to constantly replaced, slowing down production.

- But then DuPont was like, "Listen, we have this seemingly indestructible chemical, right? It doesn't react with stuff it doesn't corrode, so maybe we can try and use it against uranium hexafluoride."

So they get a bunch of this powder, they cram it together under high pressure to create these cakes, essentially.

Now you had a solid of this material that you could machine into gaskets and cylinders that you could push into these pipes and put these tube linings into the pipe, and boom, it works like magic, like a charm.

The uranium hexafluoride was no match for this magic material.

- As Gordon Fee, the manager of the nuclear weapons plant, put it, "There was never a substitute considered, as far as I know."

The material worked so well that the army wanted to use it for everything.

The same gaskets and seals were installed into fuel tanks and airplane engines to protect them from oil and water.

And weapons manufacturing plants no longer had issues with the corrosive nitric acid needed to make explosives.

DuPont saw the potential too, so they trademarked the material in 1944.

- They didn't trademark it under the name polytetrafluoroethylene 'cause, admittedly, that name kind of sucks.

So they took T-E from tetra, F-L from fluoro, and then they had a bunch of these other miracle materials, rayon, nylon.

So they took O-N from the end of those, and boom, Teflon.

- Nice.

Okay, that's a good name.

Under the army's order, DuPont ramped up Teflon production at their test plant in Arlington, New Jersey, giving their whole supply to the government.

But DuPont struggled to produce enough Teflon to meet the military's demand.

As their Arlington scientists put it, the major advantages of polytetrafluoroethylene, solvent resistance and high thermal stability, offer obstacles from the standpoint of ease in fabrication.

- You could only really mold Teflon into solids, so gasket, seals, pipes, but you couldn't put it into water to make a spray because it doesn't dissolve in water.

They actually didn't know anything that dissolved Teflon, but there was an even bigger problem at that point.

- To polymerize TFE into Teflon, you can add a reactive atom or molecule that will hijack the first carbon double bond and start the reaction.

This is called the initiator.

And the bond formed between it and the first TFE molecule releases a small amount of energy.

Then a bit of energy is also released when the next TFE molecule joins the chain and the next and the next.

And if the process isn't controlled, the reaction gets very hot very quickly.

And if it gets above 200 degrees celsius, TFE rapidly decomposes into carbon and tetrafluoromethane, which releases even more energy all at once.

This caused a massive explosion at the Arlington plant in 1944, killing two workers.

You need a way to dissipate the heat, take the heat away from the reaction without it staying in there and, therefore, expanding and creating that force.

- Yeah, and one of the ways to do that was to have the reaction happening in water, because water can absorb a huge amount of energy before it ever heats up.

- But if you inject TFE into a water cylinder, the gas doesn't dissolve.

Even at high pressure, most of the TFE just stays on top.

So if you add an initiator, the polymerization is triggered in one place, and so it can still cause an explosion.

What you need is some way to disperse the TFE throughout the water first.

And to do that, DuPont needed help.

In 1951, they purchased a special acid from 3M, the company behind Scotch Tape.

This acid, called PFOA, looked almost exactly like Teflon.

It had a chain of eight carbon atoms covered in fluorines, but at the other end, there was a double-bonded oxygen and an OH group.

That's what makes it an acid.

And since there were eight carbons in the chain, DuPont also referred to the acid as C8.

The tail end of C8, like Teflon, was hydrophobic,

but the acid head group loved water, it was hydrophilic.

So when you add C8 into water, the molecules rearrange themselves so that the heads touch the water, but the Teflon-like tails don't.

They create little bubbles all throughout the water, which are virtually dry on the inside.

If you now inject TFE and stir the whole mixture up, well, the hydrophobic gas ends up in the middle of these C8 bubbles.

And those bubbles are dispersed everywhere evenly throughout the water.

You know what this reminds me of, is soap.

So it's the great combiner that allows, like, oil and water to mix.

- And now if you sprinkle in initiator molecules, the initiator molecules also go into these bubbles.

They start the polymerization reaction, so from TFE to Teflon.

But now since it's happening spread all throughout these bubbles, the heat is evenly dissipated throughout the water, and no one explodes.

- And since Teflon is now suspended in a solution, you can spray it onto surfaces like a coating.

This thing doesn't stick to anything.

How do you stick it to the gaskets?

You know, how do you actually use it?

- Yeah, yeah, yeah, that's a good question.

So the trick was actually the surface had to be really rough.

So what you do is you sandblast it to create grooves and imperfections at this, like, nanoscopic level.

Now if you spray the coating on, what happens is, if you heat it up, the water evaporates,

the C8, it also evaporates, but Teflon, instead of it evaporating, it just softens up.

So although there's no chemical interaction here, now it's mechanically stuck to the surface.

That's how they got it to stick.

With the war over, the army lifted the secrecy bans on the Teflon patents, and DuPont was allowed to sell it commercially.

And suddenly, people all over the world were coating everyday items in Teflon, trying to create a world-changing product.

One day in 1954, a French engineer, Marc Gregoire, tried putting Teflon on his fishing gear to prevent tangles.

- But then his wife saw him doing that, and her reaction was that, "This is absolute nonsense.

No one is ever gonna use this.

You should do something that someone's actually gonna use.

So how about you put it on a pan?

Make a pan non-stick."

- And once these pans hit the market, it was a cooking revolution.

- Teflon.

- Teflon.

- Teflon.

- And DuPont knew exactly how to market it.

- Even oatmeal won't stick to Teflon.

- Hey, neat.

Let me try.

- And it wasn't just non-stick pans.

Teflon, C8, and chemicals like it were used in everything.

- Slip-Away contains the magic of DuPont's Teflon.

Suddenly, we had Teflon stain-resistant carpets and stain protection sprays like 3M's Scotchgard.

Jackets lined with Teflon were waterproof and breathable.

- Gore-Tex is the brand name.

Teflon was so inert that medical implants made out of it wouldn't be rejected by the body.

It was used to coat the Statue of Liberty's steel framework to save it from corrosion.

And even bullets were coated with Teflon to minimize the damage they did coming out of the gun barrel.

The term Teflon was so ubiquitous that when the Italian mobster John Gotti was being prosecuted in the late 1980s, none of the charges against him would stick.

So he was dubbed Teflon Don.

By the late 1990s, the Teflon business generated roughly a billion dollars in yearly sales for DuPont.

- Teflon has a great future, and its uses will be many.

- The chemicals were everywhere, even where they shouldn't be.

- He suspected that something in this creek was poisoning his cows.

Earl was desperate.

So he hired a lawyer.

- He came to our offices armed with boxes of VHS videotapes.

We started watching these videotapes, and you know, there was a serious problem here.

The animals were wasting away, and they were skin and bones, and they had tumors and black teeth.

And you could see, on the videotape, white foam coming out of the pipe on this landfill next door with these animals standing in the white foam.

The hair on their hooves was being eaten off by whatever was in the water.

- It was a discharge pipe, and it had the marking of E.I. du Pont de Nemours and Company.

And the landfill that pipe was draining from belonged to DuPont's massive factory complex outside of Parkersburg, West Virginia, just six miles away.

That factory was Washington Works, the first commercial Teflon plant.

It provided jobs for almost 2,000 people in the town.

And DuPont's presence was felt everywhere.

- I have been a resident of Parkersburg for 48 years.

I do not work for the DuPont company, but I have seen how their people have done much for the cultural growth of this community.

- There are facilities for tennis, camping, swimming, softball, and more than 20 areas equipped for cookouts and family picnics.

DuPont took care of the community.

So when the town folk got word that Earl Tennant hired a lawyer to investigate, they shunned him and his family.

As his sister-in-law put it, we'd walk into a restaurant and everybody in the restaurant would get up and leave.

But Earl wasn't scared off, and neither was Rob.

- I thought this was gonna be pretty straightforward.

See, the US Environmental Protection Agency, the EPA, dictates exactly which chemicals are safe to be disposed of in a landfill and in what amounts.

- We would get those records and permits, and it would tell us which chemical was causing this problem.

But none of those records were really showing anything that was really causing a problem, you know, nothing that would explain that white foam.

Whatever was in Earl's water wasn't on the permits.

Now, already in the 1950s, people knew that Teflon, specifically PTFE, was pretty safe.

It's a long and extremely inert molecule.

So if you ingest it, your body just flushes it out.

However, if you heat Teflon to 350 degrees Celsius, it starts releasing fumes that make people sick.

This often happened to workers in Teflon plants.

Stray PTFE powder would fall onto their cigarettes as they were working, and then later they would accidentally smoke one of these cigarettes.

Luckily, the symptoms were mild: fatigue, tightness of chest, headaches, and they would usually pass within 48 hours.

It was called polymer fume fever.

And even though it rarely happens today, it's why you should never overheat your Teflon pan to these temperatures, especially if you have pet birds at home, because the fumes are much more toxic to them.

But Teflon couldn't have poisoned Earl's cows.

There were no fumes or high temperatures, so there must have been something else in the water.

Rob filed a legal request for all of the Washington Works operational records, and DuPont sent them over, more than 60,000 documents.

- A lot of folks would try to say, "Okay, you you want a lot of documents, we'll give you a of documents" and hope that there'd be no way somebody could actually wade through all of these files and all of these materials.

But I am the kind of person that I do dig in, and I do want to go through those documents, so I actually did read all of that.

And in those files, a certain chemical kept popping up everywhere, C8.

- I never saw the kinds of things I was seeing now in these documents from DuPont.

In 1961, the same year Teflon pans hit the US market, DuPont's in-house scientists tested C8 on rats.

Ingesting as little as 1.5 milligrams of C8 per kilogram of body weight caused the rat's livers to grow abnormally.

And a dose of 570 milligrams per kilogram was lethal.

For reference, sodium cyanide, one of the most dangerous poisons, is lethal to rats in doses of five to 15 milligrams per kilogram.

But even though C8 was less fatal, it was concerning for two other reasons.

First, like Teflon, its tail is made of carbon-fluorine bonds, which makes it incredibly stable.

So C8 wouldn't break down in the environment for decades.

And second, C8 looks like the fatty acids that humans and animals need for normal functioning, just with fluorines instead of hydrogens.

So the concern was that C8 could get into the bloodstream, hitch a ride on the proteins that transport fatty acids around, and get almost anywhere in the body.

And because of the carbon-fluorine bonds, humans and animals have no way to break down C8, so it could slowly build up, mimicking those fatty acids and potentially disrupting the systems they regulate, like the liver.

- Toxic, persistent, bioaccumulative.

So the concern was it's like a ticking time bomb. It's got more opportunity to cause harm.

As a safety measure, that same rat study suggested that all these materials should be handled with extreme care and that contact with skin should be strictly avoided.

In 1962, DuPont redid the study and confirmed that high doses of C8 kill rats through injury to the stomach, intestine, brain, lungs, and pancreas.

Then in 1965, they found those same toxic effects in dogs.

The evidence was mounting.

- They were even studying monkeys.

Some of the monkeys were dropping dead.

These chemicals were causing toxic effects in multiple organ systems in multiple species.

All these studies weren't being shared with the scientific community.

- And likely no one outside of DuPont would've noticed something was wrong if it was not for...

- Tooth decay, the most widespread of all diseases.

In the 1950s, tooth decay was a nationwide problem.

So the US started adding inorganic fluorides like sodium fluoride to the public water supply.

This helped fight cavities.

- 16 years after fluoridation, all children will have 65% less tooth decay.

In 1975, researchers wanted to know if that inorganic fluoride was getting into people's blood.

So they sampled blood from around the US, and the results were as expected.

More fluoride in the tap water meant more fluoride in the blood.

But they found another type of fluorine in the blood too, which was organic fluorine, carbon-fluorine bonds, and it didn't follow the same trend.

- Well, these researchers were wondering, where's this coming from?

Because this is not a naturally occurring substance.

And they did research, and they found that 3M was making these organic fluorides, things like PFOA.

All right, so they approached 3M in 1975, asking them, "Hey, we found this stuff in the general US population's blood.

You know, could it be yours?"

And 3M pled ignorance.

- But just three months later, 3M compared the spectrum of organic fluorine from the study to their own chemicals, and it was a match.

Their chemicals were getting into the blood of people all across the United States, but they didn't tell the researchers.

3M and DuPont were worried, so they checked their own workers' blood, and they found that they too were contaminated with C8 at levels 1,000 times higher than those in the study.

And when DuPont checked their medical records, many of these workers were showing signs of liver disease.

Meanwhile, DuPont was dumping almost 10 tons of C8 into the Ohio River each year, and they were piling up thousands more tons as C8 sludge that would leach from the landfill next to Earl's farm, all while showing commercials like these.

- And the water that eventually flows to the river is collected at five points and analyzed to make sure we don't pollute the Ohio.

- And by the early '80s, the first cancer study is done in rats, and it confirms PFOA causes, not just might be linked with, but causes testicular tumors, all right?

That sends alarm bells off within the company because the concern is, of course, we're putting this in the air, we're putting in the water.

It's in Teflon.

DuPont collected samples around Washington Works, and C8 wasn't just in the river, it was in the public water supply.

So in 1984, DuPont officials met to assess whether C8 should be swapped for a safer chemical.

But their conclusion was that currently none of the options developed are, from a fine powder business standpoint, economically attractive, so C8 stuck around, and DuPont just came up with a safe dose for drinking water.

- DuPont scientists are the first people on the planet to say what would be a safe level for humans.

They calculated something like 0.6 parts per billion, which they rounded up to one.

And the importance of that is, at that time, that was about the lowest level you could detect in water.

Essentially, if we can detect it, it's too high.

- So to put that into perspective, here is one 2,500-liter tank of water. It filled to the brim.

Now, imagine you take one drop of PFOA, 0.05 milliliters, and you place it not in one of these tanks or two or three, 20 of these tanks.

That's one part per billion, and that's the number DuPont thought would be unsafe for humans to drink.

- And after determining its own safety metric, DuPont tested the landfill wastewater leaching into Earl's creek.

It came back at 1,600 parts per billion.

- They didn't tell anybody.

So at that point, I thought I had figured out what had finally happened to the cows.

Rob compiled all the evidence into a 900-page letter and sent it to the EPA, the Department of Justice, and even the US Attorney General.

And just a few months later, DuPont settled with Earl Tennant and his family for an undisclosed sum, although they didn't admit to any wrongdoing.

- But this stuff wasn't just in the water the cows were drinking.

This was in the surrounding communities' public wells, right?

People around Mr. Tennant, the tens of thousands of people in that community had likely been drinking this for decades and didn't know.

So Rob sued DuPont again, now on behalf of the 70,000 people around Parkersburg who were unwittingly exposed to C8.

And it wasn't just Parkersburg or West Virginia.

In the year 2000, researchers analyzed blood samples from thousands of Americans all across the country, and 100% of those samples came back positive for C8 at an average of five parts per billion.

But if virtually everyone in the US is contaminated, how harmful could C8 really be?

This is exactly what Rob had to find out to have a fighting chance against DuPont.

So in 2005, he spearheaded a medical study of everyone around Washington Works.

- Scientists need to know if the chemical C8 causes any health problems.

By completing a health questionnaire and having your blood tested, you can help.

Analyzing the blood samples and medical records took seven long years, and many in Parkersburg passed away before a verdict was even reached, including Earl and his wife Sandra.

But finally, in 2013, an independent science panel had the results.

They confirmed a probable link between C8 and six human diseases, including thyroid disease, testicular cancer, and kidney cancer.

And these findings were based solely on the nearby community with an average C8 blood level of 28 parts per billion.

So for example, an American male has around a 1 in 43 chance of developing kidney cancer.

It's around 1 in 73 for females, but a person with more than 30 parts per billion of C8 in their blood serum might have about double the odds, so roughly 1 in 22 for males and 1 in 37 for females.

But the data in many of these studies only included survivors, not people who might have already died from C8 exposure.

So the verdict was that the findings must be interpreted with caution.

The true risk of C8 might be even higher.

Luckily, once these studies were published in 2013, DuPont was pressured by the regulators to phase out C8.

And by 2017, they had to pay out over $600 million to victims of C8 exposure, which is a pretty small price to pay for a company that made almost $80 billion in sales just that year.

And all throughout, DuPont denied any wrongdoing, but that wasn't the end of it for Parkersburg or anyone else

because DuPont separated its entire Teflon business into a spinoff company, Chemours, that agreed to use a different chemical.

So what was it?

- They simply took C8 and knocked two carbons off and started making C6.

- They called it GenX.

Because it was shorter and had an oxygen atom interrupting the carbon chain, it was expected to be more degradable.

So Chemours claimed a dose as high as 70 parts per billion of GenX in drinking water would still be safe.

- That chemical gets shipped to the same plant in West Virginia.

So now GenX goes into the air. GenX goes into the Ohio River. GenX is found in public water supplies.

So GenX is allowed to come out into the world, be used in Teflon.

Then the cancer study is done, which shows GenX causes the exact same three tumors in rats that PFOA did: liver, testicular, and pancreatic.

And the fact that its chain is shorter also makes GenX more mobile, so it could contaminate larger areas.

The truth is we just don't know enough about it, and that's exactly the problem.

- It took us decades to get to the point of finally addressing C8.

They simply tweak it a bit, change the chemical name.

All of the science and all of the concern, that's on C8.

This is C6 or C9 or C4.

You don't have enough evidence that these other ones are bad.

This is Whac-A-Mole.

We get to the point we're addressing one and the new one pops up and we're told we have to start over.

- And it isn't just C8 or GenX.

They belong to a family of over 14,000 different manmade chemicals, all covered in carbon-fluorine bonds.

And companies can make them however they want, C7s, C9s, branched, polymers, acids.

The generic term for all of these substances is PFAS, per- and polyfluoroalkyl substances, and like Teflon, they have almost magical qualities.

They repel liquids, so PFAS are used to make clothing waterproof.

They're also grease-resistant, so we coat things like fast food wrappers and microwave popcorn bags in PFAS to prevent stains.

Waterproof lipstick and mascara, hygiene products, and even contact lenses have PFAS in.

Even the screen you're watching this on, likely has a PFAS anti-smudge coating.

The trouble is that the same carbon-fluorine bonds that make PFAS so stable and useful in consumer products also make them incredibly persistent in the environment.

Which is why you might also know PFAS under a different name, forever chemicals.

They have been found everywhere from bustling cities to untouched areas of wilderness.

Every continent, including Antarctica, has PFAS all over it.

- Almost every living creature from polar bears to birds to fish, I mean, this stuff is being found everywhere.

So massive worldwide contamination, but by completely manmade chemicals that are fingerprints back to just a couple of companies.

Even though companies knew how dangerous these chemicals were 50 years ago, they decided not to inform the public and the regulators.

So we're only finding out about this global contamination now.

And whenever that happens, media coverage can be inconsistent, which is why I've partnered up with Ground News as the sponsor of this video.

Their platform reveals how stories like these are covered across the media landscape.

For example, a recent study suggested that 23 million Americans were exposed to forever chemicals through wastewater, but you probably haven't seen the story since fewer than 40 outlets even published it.

And take a look at how different some of these headlines are.

With Ground News, you can also see that government-funded sources had limited reporting of this story, and only 9% of the publications were right-leaning.

So Ground News flagged this as a potential blind spot.

It's highlighted on their blind-spot feed where you can see stories that are disproportionately covered by one side of the political spectrum.

The whole point of Veritasium is to make videos that get to the truth, whether that's explaining misconceptions or getting to the bottom of potentially dangerous chemicals.

Ground News helps us do that, and they can help you too.

So if you, like us, care about getting to the truth, go to ground.news/ve or scan this QR code.

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And now back to PFAS.

Okay, now I wanna find out how much of these chemicals is actually in my blood.

So I have a little test here.

I hate the idea of drawing my own blood.

Okay, that was pretty easy, actually.

I was really worried that there was not gonna be enough blood coming out.

But there was plenty.

So the question is, how much of these dangerous chemicals are in my blood?

- Has anyone ever come back with blood that has zero PFAS whatsoever?

- I've been doing blood testing on PFAS since 2007, and I've never seen a non-detect.

- No way.

- So I hear that 98% of the population has PFAS in their blood, but I'm looking for that 2% that doesn't because I've yet to see them.

- That's incredible, I mean very, very bad incredible, but wow.

But if everyone on Earth has trace amounts of these chemicals in their blood, how much harm could they really be doing?

- I wanna make a distinction because it turns out not all PFAS are equally dangerous.

You can kind of split them up into two groups.

First up, you have long, repeating chains of carbon-fluorine bonds that are tens or hundreds of thousands of atoms long, so stuff like Teflon.

These are so big and inert that even if you do ingest them, your body's just gonna flush them out.

They can't be absorbed into your bloodstream, so you're pretty safe.

They're called **氟聚合物**（Fluoropolymers: 由碳氟键组成的惰性大分子） because of the long repeating chains of carbon and fluorine bonds.

But the catch is to make these fluoropolymers, stuff like Teflon, you need to use processing aids, things like PFOA or GenX, and those are the nasty ones.

These molecules are 5 to 10 carbons long, which makes them small enough to actually enter the bloodstream.

They have functional groups at the ends that are usually acids.

The most common ones are **全氟烷基酸**（Perfluoroalkyl Acids: PFAS中的一类，具有酸性官能团，易在生物体内累积），这意味着它们可以与血液中的蛋白质结合，并被输送到身体的任何地方。

所以它们会随着时间缓慢积累和堆积。

现在，PFAS不仅仅只有两类，甚至对PFAS的定义也有不同，但我们所知的大部分都与这一组中的少数化学物质有关，即这些全氟烷基酸。

PFAS的健康风险与个人暴露水平

也许关于PFAS毒性最全面的文件是由美国国家科学院、工程院和医学院于2022年发布的。

它只研究了七种全氟烷基酸。

这些是PFOA的姐妹化学品。

其中一些，如全氟辛烷磺酸（PFOS: Perfluorooctane Sulfonic Acid）和全氟己烷磺酸（PFHxS: Perfluorohexane Sulfonic Acid），在因毒性问题被逐步淘汰之前，曾被大量用于生产防污和防水产品，如3M的思高洁。

报告推测，如果血液中这七种酸的总和低于十亿分之二，应该不会有任何伤害。

如果你的水平在十亿分之二到二十之间，则存在潜在的有害健康影响。

尽管PFAS导致伤害的确切机制尚未完全了解，但暴露最常与高胆固醇、对疫苗和感染的免疫系统反应下降、肾癌以及婴儿生长迟缓相关。

但PFAS也与数十种其他疾病有关，而超过十亿分之二十的风险更大。

那么，我在这张图表上处于什么位置呢？

• 好的，我这里有你的结果。

• 你不会在我看到我的结果之前告诉我你的结果吧？

• 不会。

• 好的。

• 你的PFOA呈阳性。

• 好的。

• 美国人的PFOA水平从2000年左右的十亿分之五下降到你现在的十亿分之1.46。

所以你对一个美国人来说非常平均。

• 太棒了。

好的。

• 好消息是，你和我都没有GenX，这很棒。

• 好的，我们走。

• 但真正的惊喜，我想是姐妹化学品PFOS，它的使用方式类似。

比如防污地毯、经过处理的衣物，你的结果是十亿分之8.93，而美国平均水平是十亿分之4.3。

• 是的。

• 这太疯狂了。

• 是的，这很疯狂，因为它在2002年就基本停产了。

• 这不是我预期的结果。

我老实说，我预期的是非常无聊的结果，比如，是的，你处于中等水平或略低。

• 然后对于PFHxS，基本上是PFOS，但有六个而不是八个碳原子，你的水平接近十亿分之七，但美国平均水平是十亿分之一。

你比95%的美国人都要高。

• 这让我震惊，因为我完全是带着预期自己大致处于平均水平的心情来参加这次会议的。

• 是的，对我来说，这很可怕。

你知道，你过着正常的生活，认为你照顾好了一切，然后你体内有你从未听说过的高浓度化学物质。

我血液中检测到的所有PFAS的总和是十亿分之17.92，是美国中位数的两倍多。

我略低于国家科学院建议对PFAS相关疾病进行额外筛查的水平。

我没想到我的水平会这么高。

我很想把这个水平降下来一点，到一个我觉得更符合普通人群的水平。

• 是的。

• 但，这些东西是从哪里来的呢？

我们接触“永远的化学品”主要有三种方式，你最常在媒体上听到的可能是含有PFAS的产品。

• 洗发水、牙线、油漆、清漆。

• 潜在危险的化学品。

• 危险化学品，有毒化学品。

• 人们正在扔掉他们的不粘锅。

我妻子一年多前扔掉了我们所有的不粘锅，从那以后，我们一直在使用不锈钢锅。

她非常擅长让它不粘。

我则不那么擅长。

但平底锅真的是问题所在吗？

锅具上的实际涂层是特氟龙，它再次只是碳氟键的长而惰性链。

所以即使你摄入它，它也不会与你的身体发生反应。

如果你家里有这样的锅，你可能不需要扔掉它。

大多数其他含有PFAS的产品也是如此。

防水衣物、防污家具和防汗表带都可能释放一定水平的PFAS，但通过皮肤直接接触的风险可能很低。

所以更大的问题是，这些产品中的PFAS如何轻易地进入环境。

许多制造这些产品的工厂在控制化学品方面没有良好的记录。

• 人们不明白，你看到的那些故事，例如在西弗吉尼亚州社区发生的事情，这与我们现在在澳大利亚、日本、意大利、德国、英国看到的是相同的化学物质和相同的事情。

我的意思是，很多人仍然没有意识到这些是相同的化学品。

我们接触的第二个主要来源是食物。

很多食物都用PFAS处理过的材料包装，比如外卖盒、微波爆米花袋和汉堡包装纸。

它在汉堡包装纸上。

量很小吗？

量小得可笑吗？

• 我们实际上在实验室里用通常含有PFAS的物品进行了测试。

比如微波爆米花、快餐包装纸、防水纸杯。

所以我这里有伦敦一户人家的自来水。

我们能烧点水吗？

因为你通常在这些产品热的时候与它们互动，然后看看是否有PFAS渗出，你可能会吃掉或喝掉它们。

• 这是公民科学，对吧？

所以，可能有一些误差，但通过一个可靠的对照组，然后用相同的自来水流向所有这些，我们至少可以得到一些东西，是的。

• 是的，即使我们什么也没得到，我们也会知道人们使用这些产品可能是安全的。

好的。

• 搅拌一下。

• 是的，让PFAS充分进入水中。

• 让汁液流动。

• 让PFAS的汁液流动。

• 嗯，它应该对人类食用是安全的。

• 是的。

• 这就是疯狂之处。

我们用热水，沸水，搅拌了大约30秒，然后我们测试了那水，看看是否有用于涂覆这些物品的PFAS会实际进入水中。

所以这是我得到的结果。

现在这些是万亿分之几的水平。

所以对于PFOA，好消息是。

除了微波爆米花，基本上没有在任何地方检测到。

我要说这些水平非常低，但别急，因为微波爆米花的情况更糟。

• 微波爆米花的问题在于，它在被你放入微波炉之前，已经在那里包裹着爆米花几个月甚至几年了。

这给了这些化学品足够的时间渗入油脂，然后它会遍布爆米花，你就会吃掉它。

这可以解释我们自己的一些结果。

在爆米花袋测试后，全氟戊酸（PFPeA: Perfluoropentanoic Acid，PFOA的一种短链变体）的水平回到了万亿分之10。

你可以在其他一些PFAS种类中看到类似的结果。

• 但微波爆米花对PFOS的含量实际上有所下降。

这可能是为什么？

我们实际上不知道。

• 我本来想说也许PFOS，就像，去了那个包装纸上找到了它的朋友，然后就呆在那里了。

• 是的，有可能。

我知道我们只做了一次测试。

没有重复测量，所以我们不能从中得出太多结论，但有一点值得一提的是，当你使用这些产品时，它们会渗入你的水和食物中。

• 研究也倾向于同意这一点。

2019年的一项研究发现，吃快餐和特别是微波爆米花会增加你的PFAS负荷，而吃家常饭则不会。

但即使是像在盘子里而不是在原始包装中重新加热食物这样简单的事情，也可以防止PFAS迁移到你的食物中。

现在，你可能会认为我们在伦敦自来水中检测到的这些万亿分之几的水平与你在人体血液中发现的十亿分之几的水平相比微不足道，但令人惊讶的是，你的血液中要有十亿分之二的PFOA，你不需要饮用含有十亿分之二PFOA的水。

因为PFAS会在你的身体中随着时间积累。

所以即使是含有低至万亿分之四PFOA的水，加上其他暴露，也足以维持你的血液水平如此之高。

这就是为什么，除了食物，水是你最大的暴露来源。

如果你住在PFAS工厂附近，当地水域通常受到严重污染，情况尤其如此。

但军事基地或机场附近地区也是如此。

你看，将PFOA或PFOS等化学品添加到水中会降低其表面张力，使水变得更滑，而且这些化学品也倾向于起泡。

所以它们是消防泡沫中的绝佳成分，它们传播更快，泡沫能极好地阻挡氧气。

由于军事基地和机场都经常使用这些泡沫进行消防演习，它们最终会渗入周围的土壤和地下水。

但这并没有止步于此。

• 目前，我们已经达到了PFAS的行星饱和水平，这意味着当你抬头看云并下雨时，雨水中含有至少四种PFAS物种的不安全水平。

事实证明，我们整个水循环都受到了PFAS的污染。

所以即使在青藏高原下雨，那雨水中也含有PFAS。

要查看你所在地区的水位，你可以使用这些显示美国、欧洲和澳大利亚PFAS污染的地图。

洛杉矶恩西诺（Encino）怎么样？

我在那里度过了过去10年中的7年。

• 克雷森塔谷（Crescenta Valley）。

• 那些都高。

• 是的。

• 圣克拉里塔（Santa Clarita），有一些。

PFHxS水平很高。

所以你可能从圣克拉里塔取水。

• 哇。

• 有一个计算器。

它可以给你一个你血液中血清的估计值。

我们现在可以尝试将它输入计算器，看看你是否能得到接近你实际水平的值，如果你愿意的话。

• 当然。

• PFHxS，所以成年人的典型值是十亿分之一，然后圣克拉里塔的水大约是万亿分之37。

• 如果你十年后看。

• 所以在暴露大约10年后，你的血液中将含有十亿分之6.85。

然后我可以告诉你，你的是6.84。

• 这就能解释一切了。

现在，我不能确定我的饮用水来自哪里，但如果我一直饮用受类似水平污染的水，那么这就能解释我的结果。

但如果你担心自己的水，你应该直接联系你的供应商以获取最相关的信息。

饮用水的监管如此松懈，令人担忧。

实际上，就在一年前的2024年4月，美国环保署才最终设定了饮用水中PFAS的法定限值。

PFOA的安全水平从杜邦公司最初的十亿分之一降至万亿分之四。

• 所以我们不再谈论20个水箱中的一滴PFOA，我们谈论的是5000个水箱中的一滴。

那是五个奥林匹克大小的游泳池。

如果里面甚至有一滴PFOA，环保署都会担心。

• 同样的万亿分之四限值也适用于姐妹化学品PFOS。

GenX的限值从科慕公司最初提出的万亿分之70,000降至仅10。

PFHxS也是如此。

作为参考，环保署对水中铅的限值是万亿分之10,000，对氰化物的限值是万亿分之200,000。

• 这清楚地表明了科学界有多么担忧。

应对PFAS：个人行动与未来展望

就在我们获得环保署的限值时，美国又迎来了一个新的政府，这可能会推翻一些PFAS禁令。

所以你不能总是依赖监管机构，你似乎也不能依赖制造这些物质的公司安全地处理它们。

那么你能做什么呢？

如果你的水受到污染，你可能需要考虑购买一个PFAS认证的过滤器。

反渗透（Reverse Osmosis: 一种水净化技术，通过半透膜去除水中的离子、分子和较大颗粒）、颗粒活性炭（Granulated Active Carbon: 一种用于吸附杂质的过滤介质）和离子交换过滤器（Ion Exchange Filters: 通过离子交换树脂去除水中特定离子的过滤器）都能够从饮用水中去除PFAS。

但过滤饮用水的责任不应该落到个人身上。

PFAS应该在源头，即制造过程中被捕获，在它们进入环境之前。

一些公司，如Puraffinity，正在开发定制过滤器来实现这一点。

• 所以看起来非常像实验室的实验室。

• 完全正确。

是的，是的。

那么你能给我讲讲这些管道的作用是什么，你这里有什么吗？

• 所以这些水代表了你发生过重大消防泡沫事故的地方。

所以你想过滤这些水，但基本上，概念是从顶部通过容器。

当它通过这种材料时，它基本上会粘附在水中的一些PFAS化学物质上，然后你进入处理的另一个部分和第三个部分。

• 对我来说，似乎如果PFAS如此生物累积，并且实际上持久稳定，它们不与任何东西反应。

那么你如何强制它们在这里面与物质反应呢？

• 基本上，利用这个长长的有机尾巴以及极性头部，所以你可以与极性头部进行一些静电相互作用，然后你可以与尾巴进行一些亲水和疏水相互作用。

通过结合这三种结合机制，你大大增加了结合PFAS的可能性，即使它仍然很困难。

• 好的，这里的水平已经下降了100%吗，还是你看到PFAS逐渐减少？

• 这是个很酷的问题。

• 好的。

• 所以一开始，经过这个之后，它下降了100%。

• 哦，那么问题解决了，还是？

• 问题暂时解决了。

• 好的。

好的。

• 我们现在看到的是，它将持续大约40,000个这种容器的体积。

所以一个10升的容器基本上可以为一户家庭提供一年的所有PFAS处理。

• 一年。

• 你希望这首先在工厂中实现，这样它就永远不会进入水中。

• 是的。

• 是的。

• 我们正在与含氟化学品制造商进行对话，他们确实在努力向前推进，而不是仅仅等待法规。

每个人接触PFAS的真实风险将有所不同。

这取决于几十个因素，比如你的水污染、你的生活方式、你吃什么。

但你到底应该担心多少呢？

比如说，如果我的水平是十亿分之17或18，这相当于每晚喝一杯啤酒，还是在没有防晒霜的情况下在澳大利亚阳光下暴晒？

• 所以我喜欢做的是创建这个风险等级。

在降低风险的等级方面，第一位是戒烟、锻炼、摄入健康的全食物饮食，并确保你获得七到九小时的睡眠。

然后是中等水平的干预，看你的初级保健医生，控制你的胆固醇水平。

然后在你较低的层次中，PFAS可能属于那个较低的层次。

预防PFAS暴露目前是我们唯一的选择，因为没有批准的医疗治疗方法。

然而，如果你比较不同性别之间的PFAS污染，男性的水平始终较高，至少在50岁左右更年期开始之前是这样。

这部分是因为月经、分娩和哺乳都是PFAS可以排出体外的方式。

PFAS可以通过胎盘进入胎儿，然后在怀孕期间，婴儿也可以通过母乳接触到。

• 孕妇应该极其小心。

你知道，幼儿非常容易受影响。

他们喝更多的水，他们正在成长，他们靠近经过处理的地毯等表面。

现在，并非每个人都必须因为PFAS而改变生活方式，但如果你属于高风险群体，因为怀孕，或者因为你生活或工作在PFAS污染区域，你可能需要考虑一下。

消防员的PFAS水平特别高，因为他们的装备和泡沫中都含有这些物质。

值得注意的是，2022年的一项研究发现，当消防员足够频繁地献血或献血浆时，他们可以在一年内将PFAS水平降低多达30%。

• 有点讽刺的是，我们的医疗系统又回到了放血疗法。

• 你怎么看待献血作为降低体内PFAS水平的方法？

• 我从未听说过这种策略。

这有点意思。

嗯，我当然建议人们更频繁地献血，不是因为PFAS暴露，而是因为我们急需血液。

重要的是要注意，尤其是在本届政府中，我们需要非常小心地将预算从研究机构转移，因为没有那些研究，我提供的指导将会有显著的缺陷。

我之所以能够谈论我们知道什么和不知道什么，都来自于那些研究。

所以如果我们削减这些主要机构的预算，让科学家们离开，我们只会得到越来越糟糕的信息。

我们距离适当的医疗治疗和更好的PFAS法规还有好几年，因为这极其棘手。

有些地方我们应该完全禁止PFAS，比如卫生用品、化妆品和食品包装，一些国家已经这样做了。

但我们也不能完全禁止PFAS，至少目前还不能，因为我们仍然依赖这些化学品来制造医疗植入物等。

目前，没有它们就不可能为我们的电子产品制造半导体。

• 疫苗生产的所有管道都是基于PFAS的。

它们也带我们进入太空，我们的宇航服。

但即使在这些小众应用中，我们也必须负责任地使用它。

• 人们正从许多不同的学科汇聚一堂，创造销毁机制，创造新型捕获材料，并创造新型替代品。

我对周围正在进行的所有伟大工作感到兴奋和鼓舞。

所以我认为如果人们想了解更多，我建议他们了解风险，但也了解正在开发的新技术，这些技术有望将我们引向正确的方向。

• 所以对我来说，你知道，我们能做的最重要的事情之一就是进行像我们现在这样的讨论。

如果故事和信息在那里，人们就可以做出明智的选择，决定是否继续购买含有这些材料的产品。

我们看到的是，消费者一旦意识到，就会说：“不，我们不想要这些化学品。”

公司正在自愿站出来，将这些化学品从产品中移除，因为消费者现在正在提出要求。

我们以前也遇到过含铅汽油、氟利昂和石棉的问题。

每一次，我们都进行了研究，并做出了正确的决定来逐步淘汰这些化学品。

对于PFAS，我们才刚刚开始了解这个问题。

但我希望我们能再次做出同样的决定。

如果你想更多地了解PFAS，我们已经将制作此视频所使用的所有来源附在描述中。

这实际上是我们有史以来最长的一集，如果没有我们的赞助商Ground News的帮助，我们不可能完成它。

所以如果你想更多地了解影响你和世界上其他人的问题，请访问ground.news/ve或使用此二维码。

我真的要感谢Ground News赞助此视频，也要感谢你的观看。