The Man Who Accidentally Killed The Most People In History

Aug 10, 2023

The Man Who Accidentally Killed The Most People In History

One scientist caused two environmental disasters and the deaths of millions. A part of this video is sponsored by Wren. Offset your carbon footprint on Wren: https://www.wren.co/start/veritasium. For the first 100 people who sign up, I will personally pay for the first month of your subscription!

Massive thanks to Prof. Francois Tissot for suggesting we make a video on the topic of isotope geochemistry. Huge thanks to Prof. Bruce Lanphear for consulting with us on lead and cardiovascular diseases. Thanks to the Caltech Archives for the audio of Patterson’s interview. Thanks to Vincent Mai for lending us your Snatoms kit. Thanks to Rayner Moss for the help with the fire-piston.

Patterson’s 1995 interview audio courtesy of the Archives, California Institute of Technology.

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Other great resources you should check out:
Bill Bryson has a chapter in his fantastic “A Short History of Nearly Everything”
Radiolab have a wonderful podcast: https://www.wnycstudios.org/podcasts/…
Cosmos: A Spacetime Odyssey has a wonderful episode – S1E7 which does a great job of telling the story of Clair Patterson
A fantastic Mental floss article – https://www.mentalfloss.com/article/9…

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References:

Much of the lead-crime hypothesis data is from Rick Nevin’s work – https://ricknevin.com/

WHO factsheet on lead poisoning – https://www.who.int/news-room/fact-sh…

WHO press release about the end of leaded gasoline https://news.un.org/en/story/2021/08/…

UNICEF report – https://ve42.co/UNICEF

Needleman, H. (2004). Lead poisoning. Annu. Rev. Med., 55, 209-222. https://ve42.co/Needleman1

Needleman, H. L. (1991). Human lead exposure. CRC Press. https://ve42.co/Needleman2

Needleman, H. L. et al. (1979). Deficits in psychologic and classroom performance of children with elevated dentine lead levels. New England journal of medicine, 300(13), 689-695. – https://ve42.co/Needleman3

Needleman, H. L. et al. (1996). Bone lead levels and delinquent behavior. Jama, 275(5), 363-369. https://ve42.co/Needleman4

Kovarik, W. J. (1993). The ethyl controversy: the news media and the public health debate over leaded gasoline, 1924-1926 https://ve42.co/Kovarik2

Edelmann, F. T. (2016). The life and legacy of Thomas Midgley Jr. In Papers and Proceedings of the Royal Society of Tasmania https://ve42.co/Edelmann

More, A. F. et al. (2017). Next‐generation ice core technology reveals true minimum natural levels of lead (Pb) in the atmosphere: Insights from the Black Death. GeoHealth, 1(4), 211-219. https://ve42.co/More1

McFarland, M. J., et al. (2022). PNAS 119(11), e2118631119. https://ve42.co/McFarland

Kovarik, W. (2005). Ethyl-leaded gasoline. International Journal of Occupational and Environmental Health, 11(4), 384-397. https://ve42.co/Kovarik3

Nevin, R. (2007). Understanding international crime trends: the legacy of preschool lead exposure. Environmental research, 104(3), 315-336. – https://ve42.co/Nevin2007

Ericson, J. E., et al. (1979). Skeletal concentrations of lead in ancient Peruvians. New England Journal of Medicine, 300(17), 946-951. – https://ve42.co/Ericson1

Patterson, Claire. The Isotopic Composition of Trace Quantities of Lead and Calcium https://ve42.co/Patterson1

Boutron, C. F., \u0026 Patterson, C. C. (1986). Lead concentration changes in Antarctic ice during the Wisconsin/Holocene transition. Nature, 323(6085), 222-225. – https://ve42.co/Boulton1

Patterson, C. (1956). Age of meteorites and the earth. Geochimica et Cosmochimica Acta, 10(4), 230-237. – https://ve42.co/Patterson2

Lanphear, B. P. et al (2018). Low-level lead exposure and mortality in US adults: a population-based cohort study. The Lancet Public Health, 3(4), e177-e184. – https://ve42.co/Lanphear1

Schaule, B. K., \u0026 Patterson, C. C. (1981). Lead concentrations in the northeast Pacific: evidence for global anthropogenic perturbations. Earth and Planetary Science Letters, 54(1), 97-116. – https://ve42.co/Schaule1

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Special thanks to Patreon supporters: Inconcision, Kelly Snook, TTST, Ross McCawley, Balkrishna Heroor, Chris LaClair, Avi Yashchin, John H. Austin, Jr., OnlineBookClub.org, Dmitry Kuzmichev, Matthew Gonzalez, Eric Sexton, john kiehl, Anton Ragin, Diffbot, Micah Mangione, MJP, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Clayton Greenwell, Michael Krugman, Cy ‘kkm’ K’Nelson, Sam Lutfi, Ron Neal

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Written by Derek Muller, Petr Lebedev, Chris Stewart, and Katie Barnshaw
Edited by Trenton Oliver
Filmed by Petr Lebedev
Animation by Fabio Albertelli, Jakub Misiek, Ivy Tello, Mike Radjabov, and Caleb Worcester
SFX by Shaun Clifford
Additional video/photos supplied by Getty Images
Music from Epidemic Sound
Produced by Derek Muller, Petr Lebedev, and Emily Zhang

Content

0.16 -> One single scientist created three inventions

3.44 -> that accidentally caused the deaths of millions of people,

7.84 -> including himself.

10 -> Not only that, they decreased the average intelligence of people

13.76 -> all around the world,

15.04 -> increased crime rates,

16.48 -> and caused two completely separate environmental disasters

20.08 -> that we are still dealing with today.

24.08 -> Part of this video is sponsored by Wren.

26.24 -> More about them at the end of the show.

30.4 -> In 1944, as a young chemist who had just finished his

33.76 -> Master's, Clair Patterson went to work on the Manhattan Project,

38.08 -> building the first nuclear weapons.

40.96 -> His job was to concentrate uranium-235, the fissile fuel for bombs

46.56 -> from the much more common uranium-238.

49.52 -> And this required huge machines, mass spectrometers, which separated

55.04 -> the two types of uranium by their slight difference in mass.

64.56 -> After the war, Patterson went back to grad school to get his

67.76 -> PhD, he picked a research project that would take

71.04 -> advantage of his experience with mass spectrometers:

74.48 -> measuring the age of the Earth.

78.4 -> Radioactive rocks are effectively clocks.

81.92 -> Uranium-238, for example, decays into thorium and then protactinium,

86.88 -> and then 12 More decays until it ends up as lead-206, which is stable.

92.08 -> The rate of this decay is consistent and can be

95.12 -> measured. It takes four and a half billion years for half of

99.28 -> a sample of U-238. to decay into lead-206

103.84 -> Patterson's PhD project was to determine the age of the Earth by measuring

108.32 -> the ratio of uranium to lead in primordial rocks,

112.56 -> but to calibrate his instrument, first he used zircon crystals whose

116.88 -> ages were known.

118.64 -> Zircon is ideal for this purpose,

120.8 -> because when it forms it contains trace amounts of

123.84 -> uranium but absolutely no lead.

126.88 -> So any lead that you later find inside a zircon, you know must be the product

131.76 -> of a uranium decay.

134 -> Patterson was tasked with measuring the lead content,

137.04 -> and another student, George Tilton, measured uranium

141.28 -> Tilton 's uranium measurements were fine. They matched predictions.

145.52 -> But Patterson's lead measurements were all

147.92 -> over the place. And they were many many times higher than

150.96 -> they expected.

152 -> We'd take George's uranium and my lead...

154.8 -> Not right Patterson!

157.2 -> There was lead there that didn't belong there.

160.48 -> So where was all this extra lead coming from?

163.92 -> That mystery would take over the rest of Clair Patterson's life

168.48 -> and bring him to the literal ends of the earth.

174.4 -> In 1908, a woman was driving across the Belle Isle bridge

178.24 -> in Detroit. When her car stalled.

181.12 -> A passing motorist stopped to help.

183.36 -> In those days cars needed to be hand cranked to start.

187.28 -> He knelt down and turned the crank,

190.08 -> and the engine roared to life. A little too suddenly.

194.08 -> The man couldn't get out of the way. The crank handle hit him in

197.52 -> the face and broke his jaw.

200.48 -> He died as a result of his injuries.

203.36 -> His name was Byron Carter, and he was the founder of his own car company.

208.32 -> So he was well connected in the Detroit Auto scene.

211.28 -> He counted among his close friends, the founder of Cadillac, Henry Leland.

216 -> Leland was so distraught over his friend's

218.48 -> death that he resolved to eliminate hand cranks from his vehicles.

224 -> Leland hired Charles Kettering to create a self-

226.827 -> starting car. And by 1911, he had a working prototype.

231.76 -> Hand cranking was difficult and dangerous, and best left to men,

237.2 -> but a car that started itself

240.24 -> changed everything.

242.4 -> The world's first crankless car

244.08 -> was the Cadillac Model 30. It was much more powerful than

247.2 -> cars before it. It had a top speed of 45 miles per hour and

251.2 -> 40 horsepower, double the Ford Model T. The Model 30 was a

255.76 -> huge success for Cadillac, doubling the company's annual

259.2 -> sales, but it had a problem. It was deafeningly loud.

265.36 -> In internal combustion engines a piston compresses the fuel-air mixture,

269.68 -> which is then ignited by a spark from the spark plug.

272.8 -> The expanding hot gases push the piston back down.

276.64 -> The problem with the Model 30 engine was it

279.12 -> compressed the fuel-air mixture more than previous

282.08 -> models so much in fact, that often the fuel would

285.12 -> spontaneously combust before the spark from the spark plug.

288.96 -> So rather than orderly, perfectly timed explosions,

291.84 -> you'd get multiple haphazard combustions leading to

295.28 -> turbulent pressure waves inside the cylinder. The

298.16 -> resulting sound led the problem

299.92 -> To become known as engine knocking.

303.52 -> Knocking wasn't just hard on the ears, it hurt the engine's

306.8 -> performance, it reduced power output and lowered fuel

310 -> efficiency. The vibrations also damaged the piston and

313.52 -> walls of the cylinder shortening the life of the

315.92 -> engine.

317.44 -> The good news was that engine knocking could be corrected by

320.64 -> changing the fuel. Different fuels can withstand different

324.56 -> levels of compression before detonating n-heptane for

328.32 -> example, will spontaneously combust under only a little

331.68 -> compression. Iso-octane, on the other hand can withstand a

335.28 -> much higher compression ratio before it auto ignites. So

339.52 -> it's much less likely to cause knocking. To quantify how much

343.28 -> compression a fuel can withstand scientists came up

345.84 -> with the octane rating system, they arbitrarily set

349.12 -> iso-octane to have a rating of 100 and n-heptane a rating of

353.04 -> zero. Now real fuels aren't made up of only these two

356.24 -> ingredients. They're a mix of lots of different

358.48 -> hydrocarbons. But the octane rating tells you what mixture

361.76 -> of octane and heptane gives equivalent performance. For

365.36 -> example, 98 octane fuel can withstand the same compression

368.96 -> as a mixture of 98% octane and 2% heptane. Now, I'm going to

373.36 -> take a little bit of 98 octane fuel and put it in this

377.92 -> piston. And when I compress it,

382.56 -> nothing happens which is exactly what you'd expect.

385.68 -> This fuel can withstand a lot of compression. Diesel has an

389.28 -> octane rating of 20. So it acts like a mixture of 20%

392.4 -> iso-octane and 80% n-heptane. If I put a little bit of

395.92 -> diesel in there, let's see what happens with the same

399.12 -> compression ratio.

406.56 -> There you go. You get a little explosion in there. That's

409.44 -> because this is a low octane fuel. I mean, that's what

411.84 -> diesel is meant to do. You compress it and it ignites.

414.64 -> But you don't want this sort of fuel in an engine with

418 -> spark plugs. The reason fancy cars demand high octane fuel

422.24 -> is to prevent knocking in their high-compression

424.72 -> high-performance engines.

428 -> Kettering wanted to find an additive which would increase

430.64 -> the octane rating of ordinary fuel and eliminate knocking in

434.08 -> high-compression engines. So he hired a 27-year-old

437.52 -> engineer Thomas Midgley Jr. Midgley experimented with all

441.84 -> sorts of compounds from melted butter and camphor, to ethyl

446.16 -> acetate and aluminum chloride. He later wrote, most of them

449.76 -> had no more effect than spitting in the Great Lakes.

453.68 -> Ethanol was an interesting exception, it did stop the

456.8 -> knocking, but you needed a lot of it about 10% of the fuel

460.48 -> mixture for it to be effective, that much ethanol

463.2 -> would be expensive and hard to turn a profit on. And Midgley

467.04 -> was really after an additive that was cheap, easy to

469.6 -> produce and effective even at low concentrations. So he kept

473.76 -> trying. Then he hit on tellurium. It worked

478.08 -> wonderfully as an anti knock agent, but it had a terrible

481.84 -> smell. You couldn't get rid of it by changing clothes or

485.6 -> bathing. His wife was so offended by the stench that he

489.44 -> had to sleep in the basement for seven months, Midgley

493.12 -> wrote, I don't think that although this doubled the fuel

496.16 -> economy, humanity would suffer this smell.

501.44 -> On December 3 1921, after five years of working on the

505.44 -> problem, Midgley found what he thought was the perfect

508.64 -> solution, tetraethyl lead. That's a lead atom right there

512.8 -> in the center. This additive was exactly what he was

516.24 -> looking for. It stopped the knocking, it didn't smell. It

520.16 -> was cheap to produce and readily available. Best of

523.04 -> all, you only needed one part in 1000, for it to be

526.72 -> effective. In a call to Kettering, Midgley said, can

530.24 -> you imagine how much money we're going to make with this?

533.04 -> We're going to make $200 million, maybe even more. That

537.2 -> is over 3 billion in today's dollars. Now for his

541.76 -> discovery, the American Chemical Society gave him the

544.48 -> prestigious Nichols award, and they asked him to do a series

548.16 -> of public talks, but Midgley declined. He and Kettering

552.48 -> patented the process for making Tetra ethyl led, and

555.52 -> they called their new additive Ethyl, perhaps so it might be

559.12 -> confused with another common additive ethyl alcohol they

562.72 -> made no mention of lead. Then they teamed up with three of

567.28 -> America's largest corporations General Motors, DuPont and

570.56 -> Standard Oil of New Jersey to form the Ethyl Corporation.

575.84 -> Their marketing was brilliant. No man can look at the amazing

579.92 -> record of accomplishment here in this research division,

582.48 -> without confidence that these men are going ahead with an

585.52 -> eye to the future, looking for new facts and principles,

588.8 -> which will make things better and make life easier for all of us.

603.6 -> at the 1923 Indianapolis 500, the top three finishers all

608.4 -> used Ethyl and the demand for leaded gasoline took off. To

613.52 -> keep up Ethyl Corporation had to build a new chemical plant

616.56 -> in New Jersey. But the project began terribly. Within two

620.4 -> months of operating, dozens of workers fell ill with lead

623.92 -> poisoning. Five of them died.

627.36 -> To address the public outcry, Midgley held a press

630.64 -> conference. And there he poured Tetraethyl lead onto

634.56 -> his hands, and he inhaled it for a full minute. He claimed

639.04 -> he could do this daily without harm. But Midgley knew the

643.28 -> dangers. The reason he had turned down the public talks

646.88 -> was because he spent much of 1923 in Florida, where he

651.2 -> himself was recovering from lead poisoning. He didn't go

655.28 -> anywhere near his company's product if he could help it.

660.16 -> Lead is dangerous even in small doses, it mimics calcium

664.64 -> in our bodies, so there's no efficient way to get rid of

667.2 -> it. And like calcium lead can be stored in bones for years,

671.68 -> meaning it can continue to poison the body long after the

674.48 -> initial exposure. The organ most sensitive to lead is the

678.32 -> brain. Lead breaks down the myelin sheath around axons and

682.24 -> prevents the release of neurotransmitters. That's why

685.04 -> common symptoms of lead poisoning are headaches,

687.84 -> memory loss and tingling in the hands and feet. And

691.36 -> children are particularly susceptible, lead exposure can

694.72 -> cause permanent learning disorders and behavioral

697.2 -> problems, and the dangers of lead had been known for

700.32 -> hundreds of years. Already in 1786, Benjamin Franklin

704.56 -> remarked that lead had been used for far too long

707.76 -> considering its known toxicity, "you will observe

711.12 -> with concern how long a useful truth may be known and exist

714.72 -> before it is generally received and practiced on". He

718.24 -> would have been aghast to learn that nearly 150 years

721.2 -> later, scientists planned to add lead to fuel. Doctors and

725.92 -> public health officials from MIT, Harvard, Yale, and the US

729.36 -> health service, wrote to Midgley and warned them

731.76 -> against producing Tetraethyl lead. They called lead a

734.72 -> creeping and malicious poison and a serious menace to public

738.24 -> health. Their concerns were dismissed.

743.68 -> This model shows how just the right amount of fluid

746.48 -> containing Tetraethyl lead and dye is added to the gasoline.

751.2 -> No one doubted that a lot of lead was bad for you. But how

754.72 -> much harm could a little lead do?

758.96 -> By the 1950s, millions of motorists globally were

762.4 -> burning lead in their cars and releasing it into the air.

766.4 -> Some of that lead ended up on Clair Patterson's zircon on

769.88 -> samples, preventing him from determining their age. In

773.84 -> 1952, he moved to Caltech, where he built a new lab from

777.84 -> scratch, suspicious of environmental contamination,

780.96 -> he tore the electrical cables out of the walls to remove the

784.08 -> lead solder. He cleaned the floors and benches daily with

787.68 -> ammonia and made sure that air was always being blown out of

790.96 -> the lab. To go inside, you had to wear a plastic bunny suit.

795.52 -> Patterson basically invented the cleanroom. Inside that

799.68 -> room, he turned his attention to the oldest rocks in the

803.12 -> solar system. meteorites. All the original rocks on Earth

807.52 -> had long since been destroyed by tectonic activity. But

811.12 -> meteorites come from asteroids which formed around the same

814.88 -> time as Earth. They have just been drifting through space

819.28 -> until they entered the Earth's atmosphere. So the best way to

822.88 -> measure the age of the Earth was to measure the age of

826.24 -> meteorites. Patterson measured five meteorites, each with

830.72 -> three different radiometric dating techniques, and he

833.84 -> found they were all 4.55 billion years old. That number

839.68 -> is within 0.15% of the currently accepted value for

844.24 -> the age of the earth. You know, before Patterson's

847.52 -> experiment, people thought the earth was a billion years

850.56 -> younger. So Patterson had done it. He measured the age of the

854.64 -> Earth, but he wasn't done getting rid of lead contaminants.

860.08 -> Public concern about lead exposure had continued to

862.88 -> grow. But President of Standard Oil, Frank Howard

865.84 -> pushed back saying, "We do not feel justified in giving up

869.2 -> what has come to the industry like a gift from heaven, on

872.48 -> the possibility that a hazard may be involved in it."

876.88 -> Scientists funded by the Ethyl Corporation claimed that lead

880.56 -> was a natural part of our environment, and therefore not

883.92 -> harmful to people. But Patterson wondered just how

887.44 -> natural is the lead in our environment, and he had just

891.68 -> the skills to find out.

897.84 -> He began by measuring lead in the oceans. If it were

900.96 -> natural, he expected the concentration of lead to be

903.44 -> the same regardless of depth. But if lead pollution had

907.12 -> increased recently, it would be more concentrated near the

909.92 -> surface. He took samples in the Pacific and Atlantic

913.28 -> Oceans down to a depth of four kilometers. And sure enough,

917.12 -> lead concentrations were nearly 10 times higher near

920.4 -> the surface. Lead pollution was clearly recent, but when

924.96 -> exactly had it occurred?

928.4 -> To find out Patterson had to go to Greenland and

931.28 -> Antarctica. Ice cores record the level of lead in the air

934.96 -> going back 1000s of years, the levels of lead in the

939.2 -> atmosphere have been elevated for the last 4500 years. All

943.36 -> of it is due to human activity mainly smelting ores to make

947.44 -> metal. You can see the rise and fall of the Greek and

950.8 -> Roman Empires. The dip caused by the Black Death in the

954.4 -> 1300s. And of course, the spike in the 20th century due

958.32 -> to industrialization and Tetraethyl lead.

962.96 -> So what did this do to people? Well, Patterson looked at the

966.72 -> lead levels in the teeth and bones of recently deceased

969.68 -> Americans. And for comparison, he measured the lead in bones

973.12 -> and teeth of Peruvian and Egyptian mummies. Since they

976.56 -> lived over 1600 years ago, they would have been exposed

979.84 -> to much less lead in their lifetimes. He expected to find

983.92 -> modern Americans had about 100 times as much lead in their

986.96 -> bones. But results showed it was closer to a factor of

990.4 -> 1,000. 20th century Americans had 1000 times more lead in

995.76 -> their bones than their ancestors. Studies of baby

999.68 -> teeth revealed that even Lead exposure well below the level

1002.96 -> considered safe resulted in delayed learning, decreased IQ

1007.36 -> and increased behavioral problems. And there's a broad

1011.68 -> consensus on the part of everybody except the lead

1014.24 -> industry and its spokesmen that lead is extremely toxic

1016.96 -> at extremely low doses. A follow up study showed that

1020.4 -> those with higher levels of lead in their baby teeth were

1023.2 -> many times more likely to fail out of high school. As a

1027.2 -> result of studies like these, the CDC's guidelines for the

1030.64 -> acceptable level of lead in children's blood dropped from

1033.84 -> 60 micrograms per deciliter down to 3.5. And as far as we

1039.2 -> know, today, there is no safe level of lead. Globally, lead

1044 -> is believed to be responsible for nearly two thirds of all

1047.36 -> unexplained intellectual disability. According to a

1050.8 -> study published in 2022, more than half of the current

1054.56 -> US population, that's 170 million people were exposed to

1059.04 -> high levels of lead in early childhood. Those born between

1062.32 -> 1951 and 1980, are disproportionately affected.

1066.48 -> The author's estimate that in aggregate lead caused a loss

1069.92 -> of more than 800 million IQ points. The world is less

1074.72 -> intelligent today because of leaded gasoline. But there are

1079.28 -> even more troubling correlations. The US saw a

1083.2 -> steady rise in crime from the 1970s to the 1990s, then it

1089.04 -> abruptly declined. This graph looks eerily similar to a plot

1093.76 -> of preschool blood lead levels just offset by 20 years. The

1098.96 -> obvious question is did kids who were exposed to higher

1102.16 -> levels of lead grow up to commit more crimes than they

1105.2 -> otherwise would have? You might think this is just a

1108.24 -> spurious correlation. But the same pattern appears in many

1111.04 -> countries, including Britain, Canada, and Australia. And we

1114.72 -> know there's a causal connection between lead

1116.8 -> exposure and antisocial or violent behavior. A study of

1120.64 -> 340 Teenagers found that those who were arrested were four

1124.4 -> times as likely to have elevated lead in their bones

1126.96 -> than similar demographic controls who didn't have run

1129.72 -> ins with the law. Now, this doesn't mean that lead is

1132.4 -> responsible for all of the increase in crime, but it's

1135.28 -> very likely responsible for some of it.

1139.12 -> Now, it's tough to estimate the precise death toll of

1142.4 -> lead. One of its lesser known effects is a hardening of the

1145.68 -> arteries, leading to increased cardiovascular disease. A

1150.08 -> study from 2018 found lead was likely responsible for 250,000

1155.44 -> heart disease deaths per year in the US, assuming a constant

1159.76 -> rate over the past century, that amounts to 25 million

1163.36 -> deaths in the US alone. Globally, the figure may

1167.36 -> approach 100 million. Most of those deaths are due to

1170.96 -> Midgley's decision to put lead in gasoline, as substance he

1174.96 -> knew firsthand was toxic, but he did it anyway to maximize

1178.88 -> profits. And the problem is not over. Current estimates of

1183.12 -> deaths caused by lead range from 500 to 900 thousand per

1187.68 -> year. The 2020 UNICEF report warns that one in three

1191.36 -> children globally, that's over 800 million children have

1195.68 -> blood lead levels at or above five micrograms per deciliter.

1200.32 -> A lot of this lead now comes from batteries and industrial

1203.6 -> processes, but some is still due to Midgley's invention.

1211.2 -> After Midgley's success with Ethyl, he was put in charge of

1214.08 -> another engineering project. GM wasn't just making cars but

1217.92 -> also household appliances and fridges had a problem. The two

1222.16 -> most common gases used as refrigerants were methyl

1224.96 -> formate and sulfur dioxide. One is highly toxic, the other

1229.28 -> is flammable. Midgley was tasked with creating a safer

1233.28 -> alternative and in 1928, he developed a non toxic and non

1237 -> flammable refrigerant dichlorodifluoromethane, GM

1241.76 -> called this new product Freon and to demonstrate Freon's

1245.12 -> safety, during the unveiling at the American Chemical

1247.68 -> Society, Midgley inhaled a lung full of this gas and blew

1251.92 -> out a candle. In the following decades CFCs like Freon became

1257.04 -> very popular and were used as solvents and aerosols. The

1261.36 -> problem is CFCs are light and stable. When released into the

1265.92 -> atmosphere, they climb up into the stratosphere where they

1269.84 -> can remain for 50 to 100 years. But if a CFC molecule

1274.32 -> is hit by an ultraviolet photon of just the right

1276.72 -> energy, it breaks apart, releasing a chlorine atom and

1280.96 -> this chlorine atom can then react with ozone, breaking it

1284.64 -> apart into chlorine monoxide and oxygen gas. The results

1289.28 -> was another environmental disaster: the hole in the

1292.08 -> ozone layer. With less ozone more UV light penetrates the

1295.76 -> atmosphere increasing the rates of skin cancer and

1298.4 -> cataracts. Plus CFCs are potent greenhouse gases per

1303.04 -> kilogram they produce 10,000 times more warming than CO2.

1307.44 -> The historian John McNeil wrote that Midgley had more

1310.48 -> impact on the atmosphere than any other single organism in

1314.08 -> Earth's history. An agreement to phase out CFCs the Montreal

1318.08 -> Protocol went into effect in 1989. And the ozone layer is

1322.24 -> now showing signs of recovery, although it will take many

1325.04 -> more decades to fully recover.

1328.08 -> In 1940, at the age of 51,

1330.48 -> Midgley contracted polio and became physically disabled, so

1334.16 -> to help him get up, he devised a mechanical bed controlled by

1337.36 -> a series of ropes and pulleys. On November 2 1944, while

1342 -> using the contraption, he became tangled in the ropes

1345.52 -> and died of strangulation.

1350 -> Thanks to the work of Clair Patterson, it became clear

1352.96 -> that the lead in our environment is not natural.

1356.16 -> Burning lead and combustion engines spread the toxic

1359.04 -> elements across the planet. Into the air, oceans, the snow

1363.52 -> at the South Pole and even our bones. Japan was the first to

1368.32 -> ban leaded fuel and cars in 1986. But other countries soon

1372.24 -> followed suit. Algeria was the last to do so in 2021. The UN

1378.48 -> calculates that the elimination of lead from gas

1381.04 -> saves over a million lives per year, and $2.45 trillion

1386.24 -> dollars.

1388.64 -> But leaded gas is still used, by the way in piston driven

1392.88 -> airplane engines. That's now the largest source of lead

1395.84 -> emissions into the air in the US.

1398.96 -> You will observe with concern how long a useful truth may be known and exist

1403.68 -> before it is generally received and practiced on.

1415.92 -> When I first learned about Thomas Midgley and Clair

1418.56 -> Patterson, I was amazed by how much harm or how much good a

1422.48 -> single person could do to the environment. Which brings me

1425.28 -> to the sponsor of this video Wren, an organization that's

1428.32 -> taking action on climate change. I think it's important

1431.28 -> that we tackle the climate crisis both by lobbying for

1434 -> systemic change. And by making more environmentally friendly

1437.28 -> choices ourselves. On Wren's website, you can calculate how

1440.64 -> much carbon you emit and which activities have the greatest

1443.76 -> impact. And if you like you can offset your emissions

1446.96 -> through a monthly subscription. The funds raised

1449.68 -> go to support a variety of projects that reduce

1452 -> greenhouse gases in the atmosphere. One project I

1454.96 -> particularly like involves collecting up flammable dead

1457.92 -> wood from California forests. This helps prevent wildfires.

1462.16 -> Plus the collected wood is converted into biochar, a

1465.52 -> material that locks up the carbon inside for 1000s of

1469.04 -> years. Once you sign up to offset your carbon footprint,

1472.08 -> you'll receive monthly updates from the projects you support.

1475.36 -> It's completely transparent with photos and details of

1478.64 -> every tree planted every acre reforested every tonne of

1482.4 -> carbon offset, and for the first 100 People who sign up

1485.36 -> using the link in the description. I will personally

1488.24 -> pay for the first month of your subscription. So I want

1491.28 -> to thank Wren for supporting Veritasium and I want to

1494.24 -> thank you for watching.

Source: https://www.youtube.com/watch?v=IV3dnLzthDA