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I'm Latif Nasser. This is Radiolab. Today, a story about how we humans rearrange the elemental stuff all around us and how one man's pursuit of a basic truth about the Earth revealed in an extraterrestrial explosion, a 2000 year old Peruvian skeleton, even a strand of his lab assistant's hair changed the very air we breathe.

comes to us from reporter Avira Mitra. So I guess we'll start it. Okay. Good afternoon, Dr. Patterson. It's a pleasure to talk to you. With this guy, Claire Patterson. He goes by the name Pat. And I think we'd like to start this interview with you just telling us a little bit about your background. This is from an oral history from 1995. All right. Well, I was born in a small town in the middle of Iowa that was located in the midst of a

farmland, rolling prairie type farmland in Central Iowa. And this little town at that school, it was a small school, all the students knew each other for 12 years. So you were all in one school the whole time? One school the whole time, people would move in and out. It was sort of a tribal interaction.

And so Pat's tribe... We learned how to hunt. Did all the things you do growing up in the country. Learned how to swim and fish. And we saw crops being planted. We knew about farm animals. But he was... He was...

This is science journalist Lydia Denworth. He was in some ways a farm boy, but... I knew I was different than most people. He was the kind of kid who asked his mother all kinds of questions about the world, like... Why is a drop of water round? Things like that. He set up a chemistry lab in his basement when he was 12. Oh, wow. In high school, he, you know, was always like... Science teachers would say something about electricity being a fluid. Correcting his teachers. I had to explain to him about electrons and stuff.

He was just always, always fascinated by how the world worked. And he had the ability to see beyond what others saw. You know, he made leaps. So like, for example, this is a kid from a small town, goes to a small high school, small college, and graduates in his first job out of college. He's working on the atomic bomb for the Manhattan Project. Oh, wow.

Now, to back up a little bit, at the beginning of World War II, around 1940, there were these European scientists. Like Einstein and others. Who were immigrating to the U.S. and telling anyone who would listen the Germans were making a bomb.

An atomic bomb. And they were pushing the Americans to make sure that they didn't get behind the Germans. And so when Pat graduated, some of his professors pushed him... To join the army. And help the American effort to create a nuclear bomb. So Pat enlisted, got shipped down to Oak Ridge, Tennessee. With his wife, Lori. Lori Patterson, she was also a scientist. Brilliant chemist, in fact, and also worked on the Manhattan Project.

So anyway, Oak Ridge was one of those places that they made a city overnight. 75,000 people in the end were working and living there. And we had a little dog and we went back and forth on a bus to work every day. To these top secret state-of-the-art laboratories. Buried in the mountains. And I don't think he knew what he would be doing when he got there.

But he ends up dead smack in the middle of the whole thing. Like dead smack in the middle of the bomb? Yeah, his job at Oak Ridge was to make the actual stuff in the bomb that goes boom, which was uranium. And uranium is an interesting character, an element, really.

It's the heaviest element that occurs, naturally at least. So like, you know, every element is made up of three things, protons, neutrons, and electrons. Protons and neutrons are in the middle. They're kind of what define the element. So every element has a different amount of these things.

And uranium has the most of them. Like just to give you an example, hydrogen has a weight of one, helium four, carbon has like 12, but uranium's out here, it weighs 238. It's just huge. All right, so that makes it, and this is key,

unstable because the thing you need to do with a nuclear bomb is to break an atom apart. And uranium, like I think of uranium like a guy who's walking around with like a ton of grocery bags. You know, he's just holding way too many bags, you know, walking from the grocery store back to his car. And you know, this dude's just not going to be able to make it. Along the way,

he's going to drop a bag. And that's basically uranium. It's just too big. It's holding on to too many things. So now, if that's just a couple uranium atoms mixed in with other atoms here or there, it's no big deal. But if you can put a thousand uranium dudes in a parking lot overfilled with grocery bags...

And if you just like threw an apple at one of those guys or threw a grocery bag at one of those guys, right? That dude's going to drop the bag. And then that bag is going to fall and kind of tumble onto the guy next to him. He drops two bags. And then four dudes around him tumble and fall and just drop some more bags. It's going to set off a chain reaction, basically. And that's where ship gets nuclear.

So Pat's job at Oak Ridge was to use this newfangled machine called the mass spectrometer. And what that does, it isolates different elements in regular rocks. So he's finding uranium in granite rocks. He's pulverizing these rocks, isolating uranium, purifying uranium. And he basically just spent two years doing this.

And then, August 6, 1945. A short time ago, an American airplane dropped one bomb on Hiroshima and destroyed its usefulness to the enemy. The United States drops the U-bomb, the uranium bomb. With this bomb, we have now added a new and revolutionary increase in destruction.

When the bomb exploded, temperatures on the ground reached over 7,000 degrees Fahrenheit. Tens of thousands of people were killed instantly. And that's just from the energy of the explosion. But then what happens is something arguably more horrifying.

Because when a uranium bomb explodes, now there's all this uranium around just spewing out all these protons and neutrons. And even if you didn't get killed by the bomb, those protons and neutrons, they're going to go right into your body. "...hospitals filled with patients who had not seen sick before. At first they were quarantined, considered victims of a mysterious infectious disease."

And if there's enough of it around, it's literally going to tear your body apart from the inside. And that's exactly what happened in Hiroshima.

And then we dropped a second bomb on Nagasaki. During the war, developed these concepts... Pat said, you know, as this 22-year-old kid straight out of college, like, he never really fully understood the scope of what he was doing. And that these mentors of his...

And they conveyed to young people like me that this is the thing to do. This hideous crime we were committing was, it was a necessary thing. After Japan surrenders, you know, Pat and his wife were given these commemorative pins that said Manhattan Project, A-bomb.

And according to his wife, they just threw them in the trash. So what is that? Like, is that like, is that regret or anger or shame or like, yeah, what was- I think it was probably all of those things. I think he felt like this thing that had sort of inspired him and moved him and defined his life, which was basically just curiosity about the world, understanding things, had kind of been taken advantage of and sort of used to create this real horror that

And so he just wanted to get away from all of that. I think he just wants to get back to doing science that's free of all of that. True science. It's just for understanding for its own sake. Yes. But...

That's not quite how it worked out for him. So after the bomb project, Pat and his wife, Lori, moved back to Chicago. And he enrolls to get his chemistry PhD at the university there, the University of Chicago. Started taking courses. And one day this professor comes up to him. And he said, hey, Pat. Look, I'm trying to answer this question. How old is this rock that we're sitting on?

Like, how old is the Earth? We didn't know that? No. Nobody knew the age of the Earth. People had been trying to guess at this for a long time. It started with somebody adding up all the ages of everybody in the Bible. Which got us to about, like, 6,000 years old. It's not right. And then, you know, people start finding dinosaur fossils. And it's like, okay, well, I guess this has to be a little longer than that. But still, no one knew exactly how much longer. So, Pat's professor says to him,

This is perfect for you. It's pure chemistry. And you'll be famous because you measured the age of the Earth. And what did you say? I said, good, I will do that. And then his professor said to him, It's going to be duck soup, Patterson. It's going to be duck soup, which I guess is a way of saying it's easy. That's my favorite Marx Brothers movie. Duck soup? Yeah.

Anyway, okay, sorry, keep going. Okay, so Pat's got this job now, right? No making bombs. It's just this pure scientific question. But the crazy thing is, the key to answering this question is the same thing that caused all this horror in the atom bomb. Okay. So... Intrigued. So basically, uranium is sitting around in all these rocks on Earth, and it's

doing its thing, right? Over time, it slowly drops a proton or neutron here or there. And since it's just mixed up in other rocks, it's not a huge deal.

But while it's not really hurting anyone, it is doing something else. It's decaying. It's actually changing into a different atom, a different element. So over time, really, really slowly, as it spits out protons and neutrons, the uranium atom turns into like thorium, then turns into radon and turns into bismuth. Ultimately, it turns into lead. And lead is stable. So it's just going to be lead forever, as far as we know. Mm-hmm.

And the thing about this decay is that it happens at a very predictable rate. It's very, very slow, but scientists figured out that, like, say, if you start out with a rock that only had uranium when it was formed. Now, if you look at the rock and you see, I don't know, a gram of lead, you know how long it took to make that lead. You could tell how long that rock's been around. Got it. That basically means that you have a super accurate clock hidden inside uranium.

Every rock. Clock rocks. Clock rocks. Got it. But the problem with rocks on Earth, when you try to date them, there's not good dates. No, I'm just kidding. Like, think about rocks. People look at Giovanni. Yeah, yeah. Yeah, it's just awkward, you know. No, but the problem is that, you know, when you figure out the age of a rock, that's great, but it just tells you the age of that specific rock. It just tells you how old that particular rock is.

Like, that's all you really need. How do you know that's the oldest rock or there's another rock that's even older? Or this one actually was just made yesterday in a volcano. Like, who knows? Yeah, exactly. That's the problem. The Earth is just a chaotic place, you know? And so somehow you need to get your hands on a rock that you know for sure formed at the same time as the Earth. And how could you possibly do that? Well, what Pat had to do is go to the very center of an explosion that was about a thousand times bigger than...

then the bomb that was dropped on Hiroshima. Which happened thanks to nature, actually, not humans. Out in the middle of this desert in northern Arizona. It's like red rocks, flatlands, all you could see for miles. Alright, here's a... I actually went there, met up with this guy. Hello. You alright?

That's right. How's it going? Hey. Michael. Michael Schwab. He's the tour guide. So where do you want to do this? Do you want to go out to Picture Rock all the way out there and do this? Yeah, I think that would be cool. Maybe we could just like walk and you could teach me. Yeah, absolutely. Follow me. So yeah, he walks me on this path and we're walking and talking until we get to the edge of this ridgeline. Oh my God. And look down into this huge crater. Just imagine the biggest hole that you could ever possibly grasp.

And then just amplify that. It's... I don't know how to describe this because it really just looks like someone set off a bomb in the middle and it's just a perfect circle. Almost perfect circle, yeah. It's difficult to describe in words. And basically, it's this huge crater in the middle of the desert that's almost a mile in diameter.

And it is... If you put the Washington Monument down there at the bottom... Deep. We'd actually be eye level with it. No, you got to be kidding me. Most people when they come out here don't even know what to do with themselves. They just sit in awe of it. I actually went out, talked to some people who were out there. Big hole, right? It's kind of messing with my head a little bit. Scary. Fascinating. A lot of people can determine which way it got here, but I see it as the majesty of God's hand. It is kind of a miracle how this crater got here.

To explain, a couple years before Patterson was going to answer this age of the Earth question, astrophysicists had strong enough telescopes that they were able to look into the heavens and see how other solar systems had formed. And what they were seeing is that solar systems formed

at the same time. Forms at the same time as what? In other words, like with our solar system, you might think, oh, Jupiter formed first and then maybe Earth formed later. Right. But no, they all happen together. Got it. But one planet that should have become a planet for whatever reason didn't clump together right. And it formed the asteroid belt. And in that belt, there was this big rock about like 150 feet long.

Half the size of a football field. And for countless years, it was just hanging out, floating in space. So it's just vacuum sealed in space, not getting changed. And then one day, another rock very gently tapped it. And that set it very slightly off its course. And year after year after year, its orbit is now bringing it ever so closer and closer to the sun. Hmm.

And eventually, 50,000 years ago, Mike likes to imagine it was early summer. Yeah, I like to say July 4th this thing hit as the best fireworks show ever. ♪

So July 4th, 48,000 BC. Ice age. This whole desert was grassland. And people hadn't even crossed the Bering Strait to get over here yet. Right. So you had creatures like Manny the Melancholy Mammoth, Sid the Sloth. And that day, had they looked up, they would have seen this huge flaming rock. It would have looked like a great ball of...

Almost like the bit of the sun came down. Hurtling towards them very fast. About 26,000 miles per hour fast. And then next thing you knew... This flaming rock came falling out of the sky, slammed into the earth in a huge fiery explosion. It took just 10 seconds and Meteor Crater was formed. Now when this meteor struck, there was so much force that the meteor itself was just like disintegrated.

Most of it disintegrated. But... In here, we have a picture of the crater. Some of it survived the impact. But we also have, front and center, the largest fragmented meteorite we recovered from this site. Wow. And you are welcome to touch it as well. Whoa. Okay, yes. You are not lying. This is...

Alright, how big is this thing, like in terms of size? This thing is about three feet in length. So the first thing you actually notice is that it's not totally smooth. Looks like Swiss cheese. It looks like Swiss cheese. Kind of looks like almost like an arrowhead type of shape. Or as I'm looking at it now, it kind of looks like a lopsided dinosaur skull. Yeah, it does look like a dinosaur skull. But arguably my favorite thing is that people worry all the time like, oh, doesn't anybody try to steal this?

Right. Because I'm considering it. If you try to pick it up and somehow you bring it back to your car, you can have it. Because it weighs 1,406 pounds. This three-foot thing... Weighs just under a ton. You've got to be kidding me. Mm-mm. Do you mind if I try to lift it? Absolutely. All right, here, hold. Here, let's put this down here. Hold this and point it at me. All right. Okay, I have been doing squats and deadlifts, so...

Good luck. I just want to give you a heads up that I may be the one. Good luck. So I'm just going to put my arms around this thing. Okay. It's a very futile effort, folks. It's just not happening. Holy crap. I can't even budge it. No, you can't. But... Can we try together? No? All right, all right. Okay, so now how is this going to help Pat determine the age of the Earth? Well...

He knows that this rock formed at the same time as the Earth has been perfectly preserved in space and it sings. Yeah. It's metal. This is a solid piece of metal. Yep. 92% iron and 7% nickel. And then that last 1% is 80 other trace elements. Including lead.

Bada bing, bada boom, you just measure that thing with that thing, and then you got the age of the Earth. Kind of. I mean, like, look, these are tricky equations, tricky tools. It's not easy. So before you start measuring the meteorite, you want to just, he just kind of wants to go practice on regular rocks, like regular granite rocks. Just make sure that, you know, his technique is down. Got it. Because you have to measure it so precisely. It's got to be so accurate. You really don't want to be making mistakes. Yeah.

So Pat takes a piece of granite and the machine spits out these results that are totally confusing. Like his numbers are way off. There's way too much lead in the rock. Yeah, there was lead there that didn't belong there. Like this rock would have been formed a gabillion years ago. And he's just saying there's way too much lead, there's way too much lead. And he couldn't figure out why. Why?

But one day he's like, you know what, let me just run a blank sample. Something that chemists do when they want to just test their system is you just run it. Like instead of putting this piece of rock in here, let me just run a blank. And so when he did that...

He still got, like, a whole lot of lead. So he's like, okay, my blanks are not blanks. So he knew that it was coming from the laboratory. This is a contamination issue. Right. Where did it come from? Okay. You go back and you track it down. I say, well, it must be that. So first he started with the glass speakers he was using. The vials are the first thing you're going to look at. So he tests the vials. And he goes, shit.

These glass vials are made with lead. So let's get some new vials. Right. So gets new glass vials. Special order, never were made with lead. Runs the sample again.

It's still off. And so then he's like, you know what? In this sample where I put the granite, I also put some water in. And he realizes actually the water is coming from lead pipes. And so he's like, oh crap, that's the problem. So he has to triple distill the water, boil it off, make sure he catches it in a vial that has no lead in it to make sure that his water doesn't have any contamination from the pipes it came through. So he runs the sample and it's a little better, but there's still lead there.

So now he's like obsessed. And Patterson, he's working in this lab. And it was pretty grubby. He looks at the walls and he's like... There is peeling paint. So he tests the paint. It was in the paint. So they repaint the walls. But...

Still. It was way too much lead. Then he looks at his desk where the mass spectrometer is sitting on and he figures out every joint in the desk is soldered together with lead. Oh, man. So he needs a new desk, new chairs with no lead, and then he uses saran wrap to cover every desk and every chair and every object in the room. And still...

Too much lead. Wow. And so he thinks maybe there's some lead in the dust on the floor, so he starts mopping the floors. He gets the lead numbers to come down a little bit.

And then one day he notices a co-worker's lipstick is messing up his samples. So he tests the makeup and he's like, okay, there's lead in there too. You can't wear makeup in this lab. And he eventually, he starts to get the lead number lower and lower. But then one day he's working in a lab and a little piece of his hair falls onto the desk and the lead number shoot up. He said, you know, holy shit, your hair. It's on him.

Wow, he's the contamination himself. The lead from your hair will contaminate the whole damn laboratory just from your hair. And so he shaves his head. But then one day he decides, okay, well, I'm just going to test my skin. And he ends up seeing that there's a bunch of lead in his skin. Oh, no. It's everywhere. There was lead in absolutely everything.

And in the end, he made people, they had a little ante room and you had to, you literally had to strip down to your underwear and put on this Tyvek suit. Which gets washed in acid. And have little booties on and put plastic over their hair. He builds positive pressure air vents so the air is constantly blowing and pushing anything inside the lab outside the lab. So even if you walk in with a little microgram of lead, the air may push it out.

He basically invents what we now call a clean lab. But he ultimately gets his samples down, his blank samples down to 0.1 micrograms. So that's one-tenth of one-millionth

of a gram. And that took years. But is that still too much? No, that's fine. And so after this, he's finally actually ready to go to Canyon Diablo, get this meteorite, and actually measure the damn thing that he was trying to do from the beginning. And so he took these precious samples. He puts the sample into the mass spec. And it was late at night. He was there by himself. Just basically turns a crank and boom, pops out a number. Which was four and a half billion years.

And that's, is that, is that like way? That number is the age of the earth. Wow. It's just a number, but what it represents, it's this fundamental truth. And in this moment, he's the only human being who knows the truth. He now has this window to that moment, the formation of not just the earth, but the entire solar system. Sun, Venus,

The planets, the moons, the rings around Saturn, me, you, everything comes from that. I mean, it was so exciting for him. He thought he was having a heart attack. He went to visit his parents in Iowa the next day and he made them take him to the hospital. But he was fine. It was more like a lot of adrenaline coursing through him. He calms himself down and he's like, here I go. I got the number. He publishes it in a journal. And it's just...

Like, nobody cares. No one cared about... I mean, who cares? Even today, people don't care how old the Earth is. So it definitely didn't get into any textbooks. It wasn't in the press. Seven years of his life has gone by. So it wasn't ducks. It was... It was not ducks. What's hard soup to make? It was like foie gras or something. I don't know. Something. That's good because it's also duck-related, I feel like. Yeah, yeah. Okay. But...

I discovered in all this work, a story related to lead. Like, this process of figuring out the age of the earth sort of unveiled this truth about the world to him, which is that we're totally contaminated with lead. Right. I am contaminated. You are contaminated. Every living thing is just filled with lead. And now that he's seen that, he...

Like he can't turn away from that vision. Like I almost think of it like the matrix, you know, like when you go into the matrix and you see those little green numbers falling or whatever, and you just see the world for what it is, which is just like this, this thing that no one else is seeing, you can't look away. But what happens when no one believes what you're seeing? Back in a minute.

This is Bree calling from Austin, Texas. Radiolab is supported in part by the Alfred P. Sloan Foundation, enhancing public understanding of science and technology in the modern world. More information about Sloan at www.sloan.org. Science Reporting on Radiolab is supported in part by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science. Walmart has Straight Talk Wireless, so I can keep doing me. Like hitting up all my friends for a last-minute study sesh.

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I'm Maria Konnikova. And I'm Nate Silver. And our new podcast, Risky Business, is a show about making better decisions. We're both journalists who moonlight as poker players, and that's the lens we're going to use to approach this entire show. We're going to be discussing everything from high-stakes poker to personal questions. Like whether I should call a plumber or fix my shower myself. And of course, we'll be talking about the election, too. Listen to Risky Business wherever you get your podcasts.

Latif Radiolab, back with Avere, who started with a story about uranium, which has by now decayed into lead. Yeah, which I think is probably a boring topic. It's like talking about the Beatles, you know what I mean? It's just everyone kind of knows about the Beatles and lead. You know, you could talk to anybody. Everyone now knows, like, oh, lead is bad for you. You know, lead in paint chips, like, don't eat lead, like...

But, you know, back in the 50s, people really just didn't care about this. They didn't, they weren't thinking about lead. And science of the day said, sure, lead poisoning is a thing. If you work in a mine and you, you know,

don't wash your hands and then you eat a burger after touching lead, then sure, you'll get lead poisoning. We've known that for thousands of years, but it's not like we're working in the lead mine. But for our dude, Pat, he's like, no, no, no, come on. Like something is going on here.

And he's like the only one who sees it. The Matrix is everywhere. That we're living in a dream, like we're living in a lead mine. You have to see it for yourself. Okay.

So, Pat's finding all this lead in his lab. He's stripping down to his underwear, shaving his head, and he's telling people, and they're just like, dude, who cares? Like, it's just your lab. I definitely would have said that. I would have been like, okay, yeah, so it's like an experimental nuisance. Like, that, I get that. You've proved that. Right. But Patterson believes, no, this has to be bigger, which leads him to this question, which is, okay, there's a lot of lead in my lab, but...

Is there a lot of lead out in the world? So... Lydia Denworth again. He started by looking in the ocean. So first thing he does is he gets a boat. You weren't on the boat yourself. Yes, I was. Oh, you were on the boat. Okay, okay. And I got sicker than dogs. He has a big problem with seasickness, but he's just like, whatever. I hated it. He goes out, collects a bunch of water from the Pacific Ocean, takes the water back, analyzes it, and sure enough... Lead. Yeah.

There is a ton of lead in the ocean. So I said, okay. Proof. I published a paper. And did it make waves in science or the public? No. A lot of scientists were like...

They didn't care at all. If you say so, I don't really know. I also don't really care, you know? But he's more convinced than ever. I mean, he starts walking around campus wearing a gas mask. And a lot of people thought he was just plain crazy, right? Everyone's like, dude, like, lead is natural. It's probably always been there. This isn't some new crazy thing. But Pat just doesn't believe it. There's no way it's been like this forever.

And then one day he gets into a conversation with a friend who gives him this idea. That the place to look to understand the amount of lead in the air in the past is the permafrost of the snow in like Greenland or Antarctica. Because snow in the polar regions comes out of the air. And lead, if it was in the air. And lead's in the snowflakes. It would come down out of the air and settle into the snow. And it would never leave because...

that snow and ice didn't melt. And then the next year, there's another snowfall. It doesn't melt. Then a year after that, there's another snowfall that doesn't melt. Next year, you have another one. Next year, you have another one. And the snow starts to, like, layer on top of each other, almost like the rings of a tree. It just, it's just preserved. Because it's permafrost. It's permanent frost. It's like it's permanently there, right? Yeah. Permafrost.

So now it's 1964. He goes out to Greenland. And he took his 15-year-old son with him. I thought it was pretty cool. This is Pat's son. My name is the same as his, Claire Cameron Patterson III, actually. He goes by Cam. Always have. Basically, you know, they fly out to Greenland to this military base called Camp Century. When you arrive there in a helicopter, you don't see anything except antennas and a few trailers and oil barrels. And snow.

Snow that goes three miles deep. So Pat and Cam put on all this gear. Dressed up in plastic suits. Gloves. And went down into this tunnel. That went down into the ice. To go back in time. And they cut out like four by four chunks of ice from the wall. We had a melting trailer up on the surface. So they melt down this ice, ship it all the way back to the lab. And this is where Pat can really start to see the history of lead over time.

And what he finds is that starting in like 1700, there was basically no lead at all, like nothing. And then in like 1750, with the start of the Industrial Revolution, you see the lead levels start to go up and up and up and up until 1930. The lead levels skyrocket straight upward.

And Patterson's like, well, what the hell happened in 1930? Well, the thing that changed was leaded gasoline. Suddenly, there was leaded gasoline in the air.

So long story short, in 1921, car makers were trying to figure out how to get rid of something called engine knock. Engine knock. Knock. So like, which is the pinging and bucking that engines do and it slows down their efficiency. And so there were chemists trying all sorts of different things. And eventually they put a teaspoon of lead into some gasoline. And the engine knock stopped.

Immediately. Instantly gone. And people loved it. People wanted it. By 1960, 90% of cars were using leaded gasoline. And Pat's sort of looking at his results from this permafrost, and he's like, Holy smokes. This can't be good. Yeah. It's everywhere. It's everywhere.

And he wrote this paper that basically said that lead had contaminated everything in the earth and that it's coming from leaded gasoline. And this time when his paper goes out into the world,

No one cared. Nope. You know, he sounded like a crackpot. Cam says around this time at home, his dad would sort of lose it. Get all excited. These are chimpanzee idiots. Talk about the idiots that didn't understand anything. They're wrong, okay? And I knew that, okay? Now. Because there were a lot of people being like, okay, sure, there's more lead in the air, but that doesn't mean there's more lead in us.

Next, he basically gets a hold of 2,000-year-old ancient Peruvian skeletons and takes their teeth, grinds up their teeth, and measures the amount of lead in their teeth. Then he compares that

to his own children's primary teeth. - Oh, funny. It's like baby teeth, yeah. - They're baby teeth, yeah. And he actually finds his children's teeth have 3,000 times more lead than the Peruvians. - Oh, God. - And still, people don't care. - Whoa. - 'Cause they're like, "Okay, there's more of it in us. "Seems fine. "It's not making you sick." - And when they say making you sick,

They meant, you know, killing you, making you blind, making you have seizures, things like that, right? Putting you in a coma. I mean, you know, it's not uranium. You know what I mean? It's not like people's hair and skin is just falling off and they're just vomiting blood, you know? Right. It's more subtle than that. Maybe more subtle. That's the question, you know? Is this harmful? Right. And what is the harm? And what is the harm, right? Yeah, yeah, yeah.

But what I think is interesting is Pat doesn't try to answer that question. Huh. What was your motivation at this point? Were you thinking in an environmental sense? No, I was not. Science, science, science. I didn't care two hoots about verifying what the contamination was. I see. So you were not being driven by environmental concerns. I was not. To be clear, Pat was convinced that lead was harmful. He just didn't.

wasn't interested in doing the research that showed exactly how or to what extent or how to fix it. But I had friends and colleagues who were concerned about the environment. They were concerned about people being hurt by all this. And Patterson would share his data with them. They'd come to my laboratory. He would

show them his techniques and a lot of these people would go on to use this stuff to show just how harmful lead was. It was crucial in getting lead out of food cans solder, getting lead out of glazes and this sort of stuff. And while he knew that this was a good thing,

To him, it was like this slippery slope that led back into this messy world of human motivations, into policy and politics. And the thing is that Patterson was so difficult to work with that he...

He often didn't get invited to be on the national committees that were deciding things. And one of the few times he did, he shows up in D.C. and they're talking about what should we make recommendations to reduce the level of acceptable lead in the environment to? And he just says it should be zero.

That's the acceptable level. And so they do this without him. He refuses to sign the final report. And he writes at the bottom, Dr. Patterson does not wish to be associated with this report. He writes his own addendum. He just writes this line, the mining and smelting of lead within the human environment is actually a monumental crime committed by humanity against itself, period.

Regardless, the EPA did slowly start catching up to the science and banning lead from things. Actually now they're getting lead out of paint. But to Pat, that wasn't the purpose of science. Not like real science. For him, science was how it was when he was a kid, you know? Where science isn't about solving some problem. It's not how can I solve this challenge, but why is that?

Why is a drop of water spherical? And now that Pat had been able to prove what the natural level of lead should be, he was really just left with this simple question. Why? Why? I mean, what led us to poison the Earth's biosphere with lead? He started looking at ice cores that went all the way back to 800 BC, and what he found was this wasn't the first time that this had even happened. You know, like...

Greeks, Romans, every empire has poisoned themselves with lead. That proves for 2,000 years, we have been unable to understand the evil that we are doing to ourselves. And at this point, Patterson's question starts to shift.

It becomes just a question of why are we this way? How do we think? He actually starts writing a book, and it's...

of human consciousness all over the place. It's about within the brain, neural pathways, it's about abstract rationalization, thinking, problem solving, formulation of religious myths, human civilization, the nature of scientific thought. He worked on this idea for years and never really seemed to get anywhere. And it was tough on him.

Cam said over time he noticed his dad grew angrier, more jaded, and talked less, spent less time with his kids. And on December 5th, 1995, he has an asthma attack in his office and he dies. He was 73. Less than a month after his death, January 1st, 1996, EPA banned the greatest source of all lead on earth, the one that had driven Pat crazy, leaded gasoline.

And obviously, lead is still with us today. Like, that's very clear. But in the years since Patterson's death, the amount of lead on the average freeway has decreased by 97%. And the average lead in people's blood in America has decreased by 94%. And lead experts say that all of that resulted in a five-point increase in preschoolers' IQ.

And just as a side note, the age of the Earth still stands at 4.5 billion years old, which is exactly as Patterson had calculated 70 years ago. But what really struck me when reporting this story is how little recognition Claire Patterson got over the course of his life.

But eventually some of his students banded together to nominate him for the Tyler Prize, which is an environmental award. It's kind of a big deal. And he actually won the award eight months before his death. But by all accounts, including his own,

He took no pride in it. I'm sorry to say, I don't want to... I have zero pride in any award. I want to use the word pride. Can I use the word pleasure? Gratification? No, not gratification. Pleasure. We have to use pleasure. No, good heavens. Look, I'm stupid, all right? I'm not some brilliant person or whatever. I'm a little child.

I'm not smart. I mean, good scientists are like, they have the minds of children to see through all this facade of all this other stuff that they know is stupid nonsense. They don't know stuff. They just don't see it the way other people see it. Okay, so I'm not smart. So anyway, so it's only circumstantial. It's not, that's why I don't feel any honor. I'm not to be, it's not there, not qualified to be honored. I mean, I'm just simply, it's accidental.

Reporter Avir Mitra. This episode was produced over millions of years by Matt Kielty, along with Becca Bressler, Rachel Cusick, and Maria Paz Gutierrez. Special thanks to Cliff Davidson, Paul M. Sutter, Denton Ebel, and Sam Keen. I'm Latif Nasser. Thanks for listening.

Radio Lab was created by Jad Abumrad and is edited by Soren Wheeler. Lulu Miller and Latif Nasser are our co-hosts. Susie Lechtenberg is our executive producer and Dylan Keefe is our director of sound design.

Our staff includes Simon Adler, Jeremy Bloom, Becca Bressler, Rachel Cusick, W. Harry Fortuna, David Gable, Maria Paz Gutierrez, Sindhujana Sambandham, Matt Kilty, Annie McEwen, Alex Neeson, Sara Khary, Arianne Wack, Pat Walters, and Molly Webster. With help from Tanya Chawla, Shima Oliai, Sarah Sonbach, and Candice Wong.

Our fact checkers are Diane Kelly and Emily Krieger.