Advertisement
Grab your lab coat. Let's get started
Welcome!
Welcome!
Create an account below to get 6 C&EN articles per month, receive newsletters and more - all free.
It seems this is your first time logging in online. Please enter the following information to continue.
As an ACS member you automatically get access to this site. All we need is few more details to create your reading experience.
Not you? Sign in with a different account.
Not you? Sign in with a different account.
ERROR 1
ERROR 1
ERROR 2
ERROR 2
ERROR 2
ERROR 2
ERROR 2
Password and Confirm password must match.
If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)
ERROR 2
ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.
Persistent Pollutants
The serendipitous origins of ‘forever chemicals’
Hosts David and Gina explore three historical breakthroughs that led to the proliferation of PFAS—and could help us get rid of them
by David Anderson , Gina Vitale
April 8, 2025
Credit: C&EN Illustration; AP Photo; Shutterstock
C &EN’s latest podcast Inflection Point leans on our 100-year archive to trace headline topics in science today back to their disparate and surprising roots. In each episode, we explore three lesser-known moments in science history that ultimately led us to current-day breakthroughs. With help from expert C&EN reporters, this new show examines how discoveries from our past have shaped our present and will change our future.
In our second episode, hosts David Anderson and Gina Vitale travel back in time to relive three events that ultimately led to the proliferation of PFAS. They also bring in C&EN reporter Britt Erickson to analyze how these ‘forever chemicals’ could shape our future.
Subscribe to Inflection Point now on Apple Podcasts, Spotify, or wherever you get your podcasts.
The following is a transcript of episode 2 of Inflection Point. Interviews have been edited for length and clarity.
David Anderson:
In 1938, a lab accident created a strange new material that would go on to help us build the first atomic bomb. And in 1963, saltwater aquarium hobbyists perfected a new way to filter out organic waste from their fish tanks. Meanwhile, in 1969, in a basement, a frustrated young scientist stumbled upon something during a temper tantrum that would revolutionize the outdoor-apparel industry. Independent of each other, these breakthroughs weave their way through history—
Gina Vitale:
OK, OK, David. I remember this from the last episode. You're telling me that these three seemingly random events lead to something major in the world of chemistry.
David:
Not just major in the world of chemistry—major in the world, period. This affects every single person on Earth. I'm talking about PFAS [per- and polyfluoroalkyl substances].
Gina:
This is Inflection Point.
David:
Spanning a century of reporting from C&EN. This new podcast traces discoveries from our past—
Gina:
—to how they shape our present—
David:
—and will change our future.
Gina:
I'm Gina Vitale.
David:
And I'm David Anderson. OK Gina, like I was saying, in 1938—
Gina:
David, hold on a second. I think most people have probably heard of PFAS, but maybe not everybody knows what it is.
David:
Sure. I guess that's fair. PFAS. Where do I begin? You know what? How about this? You handle this? I of course know what, exactly what PFAS is.
Gina:
Sure you do.
David:
You take the reins on this one.
Gina:
Right, right, right, right. Sure. So PFAS stands for per -and polyfluoroalkyl substances. They are a class of man-made organic compounds, and the hallmark feature of these compounds is carbon fluorine bonds.
David:
Yeah, exactly. Just checking my notes, my mental notes here, and I'm not Googling at all, these—
Gina:
I heard you tapping a little, I don't—?
David:
No, I think that was probably the wind. Anyway, a lot of molecules have carbon-fluorine bonds. Are they all PFAS?
Gina:
No. And to be clear here, the definition of what exactly counts as PFAS is still kind of in flux. This is a relatively new field of study. But a common definition—in fact, one that's been adopted by at least 24 states—is, quote, “a class of fluorinated organic chemicals containing at least one fully fluorinated carbon atom.”
David:
Fully fluorinated, yeah, I definitely understand that. I hear ya. But for the sake of our audience, maybe they don't know what it means, right?
Gina:
Right, our audience, right. So a carbon atom can bond to four other things. You can think of it as having four open slots, depending on whether the carbon atom is hanging off the end of a carbon chain or in the middle of the chain connected to two other carbons. It has either three or two open slots to bond to other things. If all of its open slots are taken by fluorine atoms, then it's fully fluorinated. If only one or two of its spots are taken by fluorine atoms, but another spot is filled by, say, a hydrogen atom, then it's a partially fluorinated carbon.
David:
Got it, OK. So for something to be PFAS, it needs to have at least one carbon atom that is fully fluorinated.
Gina:
By a common definition, yes, and that may continue to evolve.
David:
Cool. All right, great. Let’s go back to 1938, you see, Gina, refrigerators kept killing people.
Gina:
David, sorry, maybe before we get into the first inflection point, we should remind people why they care about this random class of compounds.
David:
Fair enough, go for it.
Gina:
Well, as you mentioned before, PFAS have become pretty universal in our lives. That’s because they have a lot of really useful properties. They can be heat resistant, stain resistant, nonstick, and so they’ve been applied in all kinds of things: cooking, tools, firefighting, foams, textiles.
David:
The creation of the first atomic bomb, for instance.
Gina:
The atomic bomb?
David:
Yeah, Gina, come on. I’m surprised you don’t already know about this. We covered it here at C&EN.
Gina:
Wait, really, we covered it?
David:
Yeah, we reported about this just a scant 79 years ago.
Gina:
Oh, OK.
David:
And you know what, Gina, I’m not going to let you sidetrack me this time. We are doing our inflection point, and that is that. Let’s go back to 1946.
David:
I admit this is a little bit before our time, but C&EN was around and reported on a type of PFAS that was making its debut at the annual meeting of the American Chemical Society in Atlantic City. The chemical polytetrafluoroethylene—today better known as Teflon—it actually pops up in multiple articles in the very same issue. They talk about the many uses of this new material, and you can tell they’re really excited about everything that Teflon can accomplish. They say, So great is the chemical resistance of Teflon that even such reagents as aqua regia, chlorosulfonic acid, acetyl chloride, hot sulfuric acid, hot nitric acid, and boiling solutions of sodium hydroxide do not affect the polymer.
Gina:
That’s actually crazy about aqua regia. Aqua regia is so powerful. Those are really powerful solvents.
David:
Exactly. Like you said. Basically, this stuff is indestructible.
Gina:
That’s very cool and all. But you mentioned the meeting was held in 1946. I’m just checking my history notes here, and I think that that falls after when World War II ended. And at the beginning of the show, you mentioned 1938 for this inflection point. I’m having a little time confusion here.
David:
We will get to 1938. I think you might remember I mentioned that refrigerators were killing people.
Gina:
Oh, right. Yes.
David:
You see the ACS meeting took place right after the war. But before its debut at that meeting, Teflon was obviously used in the war. And in fact, they even mention it in the story. They say Teflon was, quote, manufactured for special military uses during the war.
Gina:
Oh, sorry, that’s it. I thought you were going to continue.
David:
OK, you’re right. I mean, but as far as the article goes, that’s it. I think around that time, maybe the US kind of wanted to keep their nuclear military secrets, you know—
Gina:
Keep it close to the vest.
David:
Close to the vest, yeah. But of course, now, in 2025 the secret is kind of out.
Gina:
So we’re going to teach our listeners how to make an A-bomb?
David:
Step one, you need to refine uranium.
Gina:
Let me get my notepad out here.
David:
I think there are probably a few more steps before that, but basically that’s when Teflon comes into the picture.
Gina:
So Teflon was created to help scientists refine uranium?
David:
Of course, it did certainly help them, but it wasn’t created intentionally for that reason. This is where 1938 comes in. This was the year that Teflon was made by accident while chemists were trying to make refrigerators less deadly. Imagine this: refrigerators were killing people, Gina. They were killing them.
Gina:
Refrigerators were deadly?
David:
They would kill you in a couple different ways. They would either blow up and kill you. They would leak toxic gas and kill you. In one incident, 15 people died when refrigerant gas leaked into an apartment in Chicago in 1929. The chemicals they used as refrigerants were super volatile, flammable, toxic, you name it.
Gina:
Jeez, all right.
David:
So scientists started experimenting, trying to find a safe way to cool refrigerators. They were researching fluorine when—
Gina:
Sorry, fluorine gas? That’s actually wild. Fluorine gas is very dangerous, can really irritate your eyes and your skin and can damage your lungs.
David:
You’re right. That doesn’t sound good, although it doesn’t sound that much worse than the other things they were using. But they weren’t using fluorine gas.
Gina:
OK, thank God.
David:
They were taking fluorine and bonding it with carbon. Like you said earlier, when those two elements are bonded, they turn really stable—freaky stable.
Gina:
That’s true.
David:
You could use it in a refrigerator without killing everybody. Frigidaire did it, and then other manufacturers tried to copy their work. Chemists at DuPont were working to do just that. When they made a mistake, they opened up their chamber that they used to make fluorine carbon gas, and it wasn’t a gas anymore. It was this weird, slippery powder, and that is what we now call Teflon.
Gina:
Interesting. So I guess they must have been pretty excited when they found out what Teflon could do.
David:
I don’t think so. They shelved it.
Gina:
They just shelved it?
David:
Yeah, either they didn’t know what they had or how to market it. It sat unused for years, until the US entered the war. They were refining uranium with a process called gaseous diffusion, which involves sending uranium hexafluoride through huge lengths of pipes. This gas, like seemingly everything else I’ve just mentioned, was deadly.
Gina:
Sure.
David:
It was corrosive. It would eat through pipes, gaskets, anything like you wouldn’t believe. So when Oak Ridge chemists found out about this super tough, indestructible compound that DuPont cooked up by accident, they lined their pipes with it. And it worked.
David:
So of course, this moment in time is very charged. All at the same time, we’re creating the world’s first weapon of mass destruction. And a compound so stable that it will linger in our environment for centuries.
Gina:
Wow, that’s dark. As dire as that sounds. It’s true. People often refer to PFAS as forever chemicals. For that very reason they linger forever. Those carbon fluorine bonds we talked about earlier are some of the strongest bonds in nature. It takes a whole lot to split them apart and break down the molecule. And by definition, PFAS are lousy with those bonds.
David:
Devil’s advocate here, just because it sticks around forever, I mean, why is that bad?
Gina:
Well, there is a lot of concern about PFAS. We’re still kind of teasing apart all the different effects that it may have. So far, it seems like exposure to PFAS may impact our health—for instance, possibly increasing the risk of some cancers or interfering with how well our immune system can fight infections.
David:
Jeez. OK, that stinks.
Gina:
Yeah. And again, scientists are still trying to tease out all these risks. Plus, there are thousands of compounds that can be classified as PFAS, and not all of them have the same health effects. But according to the Agency for Toxic Substances and Disease Registry, most people in the US have been exposed to PFAS. It’s even in their blood.
Advertisement
David:
That doesn’t sound good at all. So how is this happening?
Gina:
Well, there’s a lot of different ways. You could breathe it in the air, you could eat it in something like fish, or you could even drink it in water.
David:
Ah, indestructible chemicals in our water. That sounds pretty bad. Can’t these forever chemicals go linger forever somewhere else? Do they have to be in our water?
Gina:
Yeah, it’s a good question. And actually, for more on this, I talked to one of our reporters at C&EN who covers this kind of thing a lot.
Britt Erickson:
Hi, I’m Britt Erickson, a senior correspondent at Chemical & Engineering News. I work in the policy group, and I cover things like chemical regulation. That includes PFAS. PFAS are in everything and everywhere, and just about everything that we write about has something to do with PFAS.
Gina:
So we talked a little bit about ways to get PFAS out of drinking water, and one of those ways is called foam fractionation, or foam frac.
Britt:
It’s very simple. So you’re just putting air into the into a column of water, basically. So you have an elongated column. You have an air sparger. You turn on the air, bubbles start flowing and PFAS—
David:
Oh, no no no no no no. Stop the tape. Stop the tape. Stop the tape.
Gina:
What?
David:
She’s kind of walking all over my little historical anecdotes that I like to tell on the show.
Gina:
Wait, is this an inflection point? Is this aquarium filters?
David:
Yes, it is. Well done. Woo!
Gina:
Let’s go back to 1963.
David:
So we know that, like Britt was saying, that foam fractionation uses air bubbles to latch on to stuff like PFAS. The water is run through these bubbles, and the PFAS sticks to those bubbles and is carried up to the surface of the water, where it can be collected or skimmed off.
Gina:
Right, exactly.
David:
So before people started using it to remove PFAS, it was used to remove all sorts of stuff, and not always from municipal water supplies. In fact, in 1963 the aquatics company Tunze started selling the first commercial foam fractionator for use in saltwater aquariums. In addition to filtering out waste from creatures in the tank, the bubbles used in the filtering process also helped mix in fresh oxygen from the ambient air outside the tank. So you can imagine it’s a really efficient system that solves a lot of problems for aquariums, and now we’re seeing people start to use that same technology to capture PFAS from giant municipal systems. Obviously, these need to be scaled up tremendously for giant water treatment plants, but a lot of the technology is shared between those systems and your neighbor’s $10,000 aquarium.
Gina:
Wait a minute. So this is like the little thing in an aquarium, like where you have the little diver guy and there’s, like, bubbles going up?
David:
No, no. This is different. This is—this is, like, for the major players in the aquarium world. This is mostly for people who have these huge saltwater aquariums. Instead of the filter sitting inside the tank, it actually—as far as I can tell—usually sits outside of the tank. The water is pumped into the filter and then out of the filter back into the tank.
Gina:
Gotcha, this is not your orthodontist’s office bubble machine.
David:
Maybe if you have a really fancy orthodontist, I don’t know.
Gina:
That’s true.
Gina:
And now, to be fair, the foam crack is not a perfect system. Here’s Britt again.
Britt:
Problem is, like, a lot of these contaminated sources don’t have enough PFAS in them to bubble up enough. So they have to add another surfactant to actually make it foam to do what it needs to do. So it has to be, like, a really contaminated source to do it on its own, or they can add the surfactant. But you don’t want to be adding a surfactant to get rid of a surfactant. The other problem with foam frac is that it tends to get rid of the PFOS [perfluorooctanesulfonic acid] and PFOA [perfluorooctanoic acid]—the eight-carbon ones, the long ones that we really care about—but it’s not so great with the shorter ones. The shorter ones are less hydrophobic. They’ve got that shorter tail.
David:
OK, so it’s not a perfect system.
Gina:
Yeah, but there are other systems that are pretty good at getting PFAS out of drinking water, at least even something as simple as activated charcoal is pretty good at filtering it out. But Britt says one of the big issues actually comes after we’ve separated it out of the water: we don’t really know what to do with it.
Britt:
You’re basically taking it from a liquid state, putting it into a solid, and then throwing it into a landfill. So you’re not—you’re not really getting it out of the environment; you’re just moving it from one phase to another. And then it leaches out of the landfills into the landfill leachate, gets back into the environment and back into the water.
David:
Oh, boy. I could really use a silver lining right about now. Gina, tell me some good news.
Gina:
It’s not totally hopeless. And I promise I will tell you why—right after this short break.
[break]
David:
OK, Gina, now that we’re back. You promised some good news about PFAS?
Gina:
Right, good news. So it might cheer you up to know that some companies are actually working on destroying the PFAS altogether.
David:
I thought the deal with PFAS is that it’s forever. You can’t destroy it.
Gina:
It’s nearly indestructible. To break those carbon fluorine bonds, you need tons and tons of energy. That costs a lot of money. And the methods can be hard to scale up, but they do work. And if you want to know more about that, you should check out our recent C&EN Uncovered episode, also with Britt, about how to destroy PFAS.
David:
So I guess light at the end of the tunnel—it’s a little bit reassuring, right?
Gina:
Yeah and, hey, a lot of these companies are also trying to find alternatives to PFAS in their products.
David:
Totally. And one of those companies I’m sure you’ve heard of. You might even have some of their products in your closet right now. It’s our final inflection point, Gore-Tex, and it starts in 1969.
Gina:
Yes, finally an inflection point I can understand. Gore-Tex, the fabric, uses a type of PFAS in their materials, right?
David:
Yeah, but theirs is a stretched out form of it. It’s called expanded polytetrafluoroethylene, or ePTFE. And like seemingly every leap forward in the world of PFAS innovation, this creation was a total accident.
Gina:
So Gore-Tex was a fluke?
David:
It was a total fluke. A little backstory: W. L. Gore and Associates, the company that makes Gore-Tex, never set out to make clothing at all in the first place. The company was started by a man and his son, Wilbert and Robert Gore. Wilbert was a scientist and inventor who previously worked at DuPont, the company who stumbled upon PFAS in the first place. He started his own company out of his basement making insulation for computer wires out of a type of PFAS called polytetrafluoroethylene [PTFE].
Gina:
Wait, that sounds really familiar. Is that just the fancy chemical name for Teflon?
David:
The very same. So in 1969 his son was working in the basement stretching out these long rods of PTFE. When he says he got a little frustrated and impatient with the process, he grabbed one of the rods, and instead of, like, slowly tugging it to stretch out this long rod of PTFE by hand,he said, enough of this. He yanked on it. And instead of snapping in half like he might have expected, the stuff just, like, easily stretched to the width of his wingspan like a giant length of taffy. So by pulling on it, by tugging on it like that, he literally expanded the PTFE.
Gina:
So this was how they put the E at the beginning of ePTFE.
David:
And the thing was, it’s lighter and has a totally different structure than the original material. Now, at first, just like the invention of Teflon 30 years earlier, they weren’t exactly sure what to do with it. I mean, they did know that it was porous. So eventually they figured out all these tiny holes were actually small enough to block water droplets but still let water vapor pass through. And so they kind of realized, well, this stuff could be waterproof, but it could also breathe water vapor in theory at the same time. So the first applications for this stuff were things like medical devices, space exploration equipment, and industrial seals. It wasn’t until later that Gore-Tex, the fabric we know today, was born. The idea with that is that you can have a jacket that, just like a rubber raincoat, completely stops water from getting in. But unlike a rubber coat, it could actually let sweat out in certain conditions so you could remain dry.
Advertisement
That’s very encouraging, yes. However, we have to couch our excitement a little bit here, because there is a lot of skepticism about new PFAS alternatives.
Gina:
Plus, replacing PFAS doesn’t always work like we hope it will. For instance, the EPA [US Environmental Protection Agency] found several PFAS chemicals to be even more toxic than the one they were designed to replace. In fact, this kind of phenomenon—swapping one problem chemical for another chemical that ends up having some kind of unforeseen hazard—has become so common now that there’s even a term for it: regrettable substitutions.
David:
Incredible.
Gina:
It’s definitely going to be a long road to phasing out PFAS altogether. For certain applications like firefighting foams, it’s important that they work really well, and it’s difficult to find alternatives that perform as well as PFAS does.
David:
Oh, boy, bummer alert. Yeah, I need you to fire up the good news machine one more time. Give me just something to hope for.
Gina:
We’ve definitely made some strides.
Britt:
If you ask the FDA [US Food and Drug Administration], it doesn’t exist in food packaging anymore. So, you know, we had our pizza boxes lined with it, our fast-food wrappers. They found something to replace it with.
David:
OK, all right. So a little bit of good news. I feel like I’m getting whiplash here. Her hedging it with, quote, If you ask the FDA kind of makes me raise an eyebrow a little bit.
Gina:
Yeah, that’s fair. But they found alternatives for other things, too. There are plenty of ski waxes now that you use to make your ski slippery that don’t contain any PFAS. And you can even get dental floss that is made without PFAS.
David:
Oh, OK, thank God. Yeah, my dental floss—it has PFAS in it?
Gina:
Yeah, let’s not think about that one too hard.
David:
Jeez, well, it’s a good thing. I actually don’t floss kind of one step ahead of the curve.
Gina:
Ew, really? That’s gross.
David:
No, I’m just kidding. I do.
Gina:
Are you winking at me right now?
David:
No, that was doing something else.
David:
I will confess a little bit of a downer episode.
Gina:
Yeah, this is not, maybe, as hopeful as the green hydrogen episode.
David:
A little bit more of an ominous future than a green new renewable energy future.
Gina:
Sure, yeah.
David:
But I will say, next episode I think we’ve got some interesting stuff coming up.
Gina:
Phew. OK, let’s, uh, yeah. Do you have the inflection points? Let’s, let’s hear them.
David:
I’ve got them here. Next episode is complex, I won’t lie. And the inflection points are complex to match. We’ve got a thought experiment from Einstein’s pen pal, the production of liquid helium—and for that matter, solid helium, kind of a two for one. Plus, a secret that had been hidden in plain sight for centuries, that was only unlocked in the 1980’s by two scientists working on either side of the iron curtain.
Gina:
Oh boy. Well, I’m not sure what it is, but I have a feeling it’s going to be complicated.
Gina:
Inflection Point is a podcast project from Chemical & Engineering News.
David:
Chemical & Engineering News is the official news outlet of the American Chemical Society.
Gina:
Music by Kirk Onstad and Shutterstock.
David:
Written, produced, and hosted by Gina Vitale and David Anderson.
Gina:
Thanks for listening.
Chemical & Engineering News
ISSN 0009-2347
Copyright © 2025 American Chemical Society
You might also like...
The power is now in your (nitrile gloved) hands
Sign up for a free account to get more articles. Or choose the ACS option that’s right for you.
Already have an ACS ID? Log in
Join the conversation
Contact the reporter
Submit a Letter to the Editor for publication
Engage with us on X