One single scientist created
three inventions that accidentally caused the deaths
of millions of people, including himself. Not only that, they decreased the
average intelligence of people all around the world, increased crime rates, and caused two completely
separate environmental disasters that we are still dealing with today. Part of this video is
sponsored by Wren. More about them at the end of the show. In 1944, as a young chemist
who had just finished his Master's, Clair Patterson went
to work on the Manhattan Project, building the first
nuclear weapons. His job was to concentrate uranium-235,
the fissile fuel for bombs from the much more common
uranium-238. And this required huge machines, mass
spectrometers, which separated the two types of uranium by
their slight difference in mass. After the war, Patterson went
back to grad school to get his PhD, he picked a research
project that would take advantage of his experience
with mass spectrometers: measuring the age of the
Earth. Radioactive rocks are
effectively clocks. Uranium-238, for example, decays into
thorium and then protactinium, and then 12 More decays until
it ends up as lead-206, which is stable. The rate of this
decay is consistent and can be measured.
It takes four and a
half billion years for half of a sample of U-238. to decay
into lead-206 Patterson's PhD project was to determine the
age of the Earth by measuring the ratio of uranium to lead
in primordial rocks, but to calibrate his instrument, first
he used zircon crystals whose ages were known. Zircon is ideal for this purpose, because when it forms it
contains trace amounts of uranium but absolutely no
lead. So any lead that you later find inside a zircon,
you know must be the product of a uranium decay. Patterson was tasked with
measuring the lead content, and another student, George
Tilton, measured uranium Tilton 's uranium measurements
were fine. They matched predictions. But Patterson's
lead measurements were all over the place. And they were
many many times higher than they expected. We'd take George's uranium and my lead…
Not right Patterson! There was lead there that
didn't belong there. So where was all this extra
lead coming from? That mystery would take over the rest of
Clair Patterson's life and bring him to the literal ends
of the earth. In 1908, a woman was driving
across the Belle Isle bridge in Detroit. When her car
stalled. A passing motorist stopped to help. In those days
cars needed to be hand cranked to start. He knelt down and
turned the crank, and the engine roared to life. A
little too suddenly. The man couldn't get out of the way.
The crank handle hit him in the face and broke his jaw. He died as a result of his
injuries. His name was Byron Carter, and he was the founder
of his own car company. So he was well connected in the
Detroit Auto scene. He counted among his close friends, the
founder of Cadillac, Henry Leland. Leland was so
distraught over his friend's death that he resolved to
eliminate hand cranks from his vehicles.
Leland hired Charles
Kettering to create a self- starting car. And by 1911, he
had a working prototype. Hand cranking was difficult and
dangerous, and best left to men, but a car that started itself changed everything. The world's first crankless car was the Cadillac Model 30. It
was much more powerful than cars before it. It had a top
speed of 45 miles per hour and 40 horsepower, double the Ford
Model T. The Model 30 was a huge success for Cadillac,
doubling the company's annual sales, but it had a problem.
It was deafeningly loud. In internal combustion engines
a piston compresses the fuel-air mixture, which is then
ignited by a spark from the spark plug. The expanding hot
gases push the piston back down. The problem with the
Model 30 engine was it compressed the fuel-air
mixture more than previous models so much in fact, that
often the fuel would spontaneously combust before
the spark from the spark plug. So rather than orderly,
perfectly timed explosions, you'd get multiple haphazard
combustions leading to turbulent pressure waves
inside the cylinder. The resulting sound led the
problem To become known as engine
knocking. Knocking wasn't just hard on
the ears, it hurt the engine's performance, it reduced power
output and lowered fuel efficiency.
The vibrations
also damaged the piston and walls of the cylinder
shortening the life of the engine. The good news was that engine
knocking could be corrected by changing the fuel. Different
fuels can withstand different levels of compression before
detonating n-heptane for example, will spontaneously
combust under only a little compression. Iso-octane, on
the other hand can withstand a much higher compression ratio
before it auto ignites. So it's much less likely to cause
knocking. To quantify how much compression a fuel can
withstand scientists came up with the octane rating system,
they arbitrarily set iso-octane to have a rating of
100 and n-heptane a rating of zero. Now real fuels aren't
made up of only these two ingredients. They're a mix of
lots of different hydrocarbons. But the octane
rating tells you what mixture of octane and heptane gives
equivalent performance. For example, 98 octane fuel can
withstand the same compression as a mixture of 98% octane and
2% heptane. Now, I'm going to take a little bit of 98 octane
fuel and put it in this piston. And when I compress
it, nothing happens which is
exactly what you'd expect.
This fuel can withstand a lot
of compression. Diesel has an octane rating of 20. So it
acts like a mixture of 20% iso-octane and 80% n-heptane.
If I put a little bit of diesel in there, let's see
what happens with the same compression ratio. There you go. You get a little
explosion in there. That's because this is a low octane
fuel. I mean, that's what diesel is meant to do. You
compress it and it ignites. But you don't want this sort
of fuel in an engine with spark plugs. The reason fancy
cars demand high octane fuel is to prevent knocking in
their high-compression high-performance engines. Kettering wanted to find an
additive which would increase the octane rating of ordinary
fuel and eliminate knocking in high-compression engines. So
he hired a 27-year-old engineer Thomas Midgley Jr.
Midgley experimented with all sorts of compounds from melted
butter and camphor, to ethyl acetate and aluminum chloride.
He later wrote, most of them had no more effect than
spitting in the Great Lakes.
Ethanol was an interesting
exception, it did stop the knocking, but you needed a lot
of it about 10% of the fuel mixture for it to be
effective, that much ethanol would be expensive and hard to
turn a profit on. And Midgley was really after an additive
that was cheap, easy to produce and effective even at
low concentrations. So he kept trying. Then he hit on
tellurium. It worked wonderfully as an anti knock
agent, but it had a terrible smell. You couldn't get rid of
it by changing clothes or bathing.
His wife was so
offended by the stench that he had to sleep in the basement
for seven months, Midgley wrote, I don't think that
although this doubled the fuel economy, humanity would suffer
this smell. On December 3 1921, after five
years of working on the problem, Midgley found what he
thought was the perfect solution, tetraethyl lead.
That's a lead atom right there in the center. This additive
was exactly what he was looking for. It stopped the
knocking, it didn't smell. It was cheap to produce and
readily available. Best of all, you only needed one part
in 1000, for it to be effective. In a call to
Kettering, Midgley said, can you imagine how much money
we're going to make with this? We're going to make $200
million, maybe even more. That is over 3 billion in today's
dollars. Now for his discovery, the American
Chemical Society gave him the prestigious Nichols award, and
they asked him to do a series of public talks, but Midgley
declined. He and Kettering patented the process for
making Tetra ethyl led, and they called their new additive
Ethyl, perhaps so it might be confused with another common
additive ethyl alcohol they made no mention of lead.
Then
they teamed up with three of America's largest corporations
General Motors, DuPont and Standard Oil of New Jersey to
form the Ethyl Corporation. Their marketing was brilliant.
No man can look at the amazing record of accomplishment here
in this research division, without confidence that these
men are going ahead with an eye to the future, looking for
new facts and principles, which will make things better
and make life easier for all of us. at the 1923 Indianapolis 500,
the top three finishers all used Ethyl and the demand for
leaded gasoline took off. To keep up Ethyl Corporation had
to build a new chemical plant in New Jersey.
But the project
began terribly. Within two months of operating, dozens of
workers fell ill with lead poisoning. Five of them died. To address the public outcry,
Midgley held a press conference. And there he
poured Tetraethyl lead onto his hands, and he inhaled it
for a full minute. He claimed he could do this daily without
harm. But Midgley knew the dangers. The reason he had
turned down the public talks was because he spent much of
1923 in Florida, where he himself was recovering from
lead poisoning. He didn't go anywhere near his company's
product if he could help it. Lead is dangerous even in
small doses, it mimics calcium in our bodies, so there's no
efficient way to get rid of it. And like calcium lead can
be stored in bones for years, meaning it can continue to
poison the body long after the initial exposure. The organ
most sensitive to lead is the brain. Lead breaks down the
myelin sheath around axons and prevents the release of
neurotransmitters. That's why common symptoms of lead
poisoning are headaches, memory loss and tingling in
the hands and feet.
And children are particularly
susceptible, lead exposure can cause permanent learning
disorders and behavioral problems, and the dangers of
lead had been known for hundreds of years. Already in
1786, Benjamin Franklin remarked that lead had been
used for far too long considering its known
toxicity, "you will observe with concern how long a useful
truth may be known and exist before it is generally
received and practiced on". He would have been aghast to
learn that nearly 150 years later, scientists planned to add
lead to fuel. Doctors and public health officials from
MIT, Harvard, Yale, and the US health service, wrote to
Midgley and warned them against producing Tetraethyl
lead. They called lead a creeping and malicious poison
and a serious menace to public health.
Their concerns were
dismissed. This model shows how just the
right amount of fluid containing Tetraethyl lead and
dye is added to the gasoline. No one doubted that a lot of
lead was bad for you. But how much harm could a little lead
do? By the 1950s, millions of
motorists globally were burning lead in their cars and
releasing it into the air. Some of that lead ended up on
Clair Patterson's zircon on samples, preventing him from
determining their age. In 1952, he moved to Caltech,
where he built a new lab from scratch, suspicious of
environmental contamination, he tore the electrical cables
out of the walls to remove the lead solder. He cleaned the
floors and benches daily with ammonia and made sure that air
was always being blown out of the lab. To go inside, you had
to wear a plastic bunny suit. Patterson basically invented
the cleanroom. Inside that room, he turned his attention
to the oldest rocks in the solar system. meteorites. All
the original rocks on Earth had long since been destroyed
by tectonic activity. But meteorites come from asteroids
which formed around the same time as Earth.
They have just
been drifting through space until they entered the Earth's
atmosphere. So the best way to measure the age of the Earth
was to measure the age of meteorites. Patterson measured
five meteorites, each with three different radiometric
dating techniques, and he found they were all 4.55
billion years old. That number is within 0.15% of the
currently accepted value for the age of the earth. You
know, before Patterson's experiment, people thought the
earth was a billion years younger. So Patterson had done
it. He measured the age of the Earth, but he wasn't done
getting rid of lead contaminants. Public concern about lead
exposure had continued to grow. But President of
Standard Oil, Frank Howard pushed back saying, "We do not
feel justified in giving up what has come to the industry
like a gift from heaven, on the possibility that a hazard
may be involved in it." Scientists funded by the Ethyl
Corporation claimed that lead was a natural part of our
environment, and therefore not harmful to people.
But
Patterson wondered just how natural is the lead in our
environment, and he had just the skills to find out. He began by measuring lead in
the oceans. If it were natural, he expected the
concentration of lead to be the same regardless of depth.
But if lead pollution had increased recently, it would
be more concentrated near the surface. He took samples in
the Pacific and Atlantic Oceans down to a depth of four
kilometers.
And sure enough, lead concentrations were
nearly 10 times higher near the surface. Lead pollution
was clearly recent, but when exactly had it occurred? To find out Patterson had to
go to Greenland and Antarctica. Ice cores record
the level of lead in the air going back 1000s of years, the
levels of lead in the atmosphere have been elevated
for the last 4500 years. All of it is due to human activity
mainly smelting ores to make metal. You can see the rise
and fall of the Greek and Roman Empires. The dip caused
by the Black Death in the 1300s. And of course, the
spike in the 20th century due to industrialization and
Tetraethyl lead. So what did this do to people?
Well, Patterson looked at the lead levels in the teeth and
bones of recently deceased Americans. And for comparison,
he measured the lead in bones and teeth of Peruvian and
Egyptian mummies.
Since they lived over 1600 years ago,
they would have been exposed to much less lead in their
lifetimes. He expected to find modern Americans had about 100
times as much lead in their bones. But results showed it
was closer to a factor of 1,000. 20th century Americans
had 1000 times more lead in their bones than their
ancestors. Studies of baby teeth revealed that even Lead
exposure well below the level considered safe resulted in
delayed learning, decreased IQ and increased behavioral
problems. And there's a broad consensus on the part of
everybody except the lead industry and its spokesmen
that lead is extremely toxic at extremely low doses. A
follow up study showed that those with higher levels of
lead in their baby teeth were many times more likely to fail
out of high school. As a result of studies like these,
the CDC's guidelines for the acceptable level of lead in
children's blood dropped from 60 micrograms per deciliter
down to 3.5. And as far as we know, today, there is no safe
level of lead. Globally, lead is believed to be responsible
for nearly two thirds of all unexplained intellectual
disability.
According to a study published in 2022,
more than half of the current US population, that's 170
million people were exposed to high levels of lead in early
childhood. Those born between 1951 and 1980, are
disproportionately affected. The author's estimate that in
aggregate lead caused a loss of more than 800 million IQ
points. The world is less intelligent today because of
leaded gasoline. But there are even more troubling
correlations. The US saw a steady rise in crime from the
1970s to the 1990s, then it abruptly declined. This graph
looks eerily similar to a plot of preschool blood lead levels
just offset by 20 years. The obvious question is did kids
who were exposed to higher levels of lead grow up to
commit more crimes than they otherwise would have? You
might think this is just a spurious correlation.
But the
same pattern appears in many countries, including Britain,
Canada, and Australia. And we know there's a causal
connection between lead exposure and antisocial or
violent behavior. A study of 340 Teenagers found that those
who were arrested were four times as likely to have
elevated lead in their bones than similar demographic
controls who didn't have run ins with the law. Now, this
doesn't mean that lead is responsible for all of the
increase in crime, but it's very likely responsible for
some of it. Now, it's tough to estimate
the precise death toll of lead. One of its lesser known
effects is a hardening of the arteries, leading to increased
cardiovascular disease. A study from 2018 found lead was
likely responsible for 250,000 heart disease deaths per year
in the US, assuming a constant rate over the past century,
that amounts to 25 million deaths in the US alone.
Globally, the figure may approach 100 million. Most of
those deaths are due to Midgley's decision to put lead
in gasoline, as substance he knew firsthand was toxic, but
he did it anyway to maximize profits.
And the problem is
not over. Current estimates of deaths caused by lead range
from 500 to 900 thousand per year. The 2020 UNICEF report
warns that one in three children globally, that's over
800 million children have blood lead levels at or above
five micrograms per deciliter. A lot of this lead now comes
from batteries and industrial processes, but some is still
due to Midgley's invention. After Midgley's success with
Ethyl, he was put in charge of another engineering project.
GM wasn't just making cars but also household appliances and
fridges had a problem. The two most common gases used as
refrigerants were methyl formate and sulfur dioxide.
One is highly toxic, the other is flammable. Midgley was
tasked with creating a safer alternative and in 1928, he
developed a non toxic and non flammable refrigerant
dichlorodifluoromethane, GM called this new product Freon
and to demonstrate Freon's safety, during the unveiling
at the American Chemical Society, Midgley inhaled a
lung full of this gas and blew out a candle.
In the following
decades CFCs like Freon became very popular and were used as
solvents and aerosols. The problem is CFCs are light and
stable. When released into the atmosphere, they climb up into
the stratosphere where they can remain for 50 to 100
years. But if a CFC molecule is hit by an ultraviolet
photon of just the right energy, it breaks apart,
releasing a chlorine atom and this chlorine atom can then
react with ozone, breaking it apart into chlorine monoxide
and oxygen gas. The results was another environmental
disaster: the hole in the ozone layer. With less ozone
more UV light penetrates the atmosphere increasing the
rates of skin cancer and cataracts. Plus CFCs are
potent greenhouse gases per kilogram they produce 10,000
times more warming than CO2. The historian John McNeil
wrote that Midgley had more impact on the atmosphere than
any other single organism in Earth's history. An agreement
to phase out CFCs the Montreal Protocol went into effect in
1989. And the ozone layer is now showing signs of recovery,
although it will take many more decades to fully recover. In 1940, at the age of 51, Midgley contracted polio and
became physically disabled, so to help him get up, he devised
a mechanical bed controlled by a series of ropes and pulleys.
On November 2 1944, while using the contraption, he
became tangled in the ropes and died of strangulation.
Thanks to the work of Clair
Patterson, it became clear that the lead in our
environment is not natural. Burning lead and combustion
engines spread the toxic elements across the planet.
Into the air, oceans, the snow at the South Pole and even our
bones. Japan was the first to ban leaded fuel and cars in
1986. But other countries soon followed suit. Algeria was the
last to do so in 2021. The UN calculates that the
elimination of lead from gas saves over a million lives per
year, and $2.45 trillion dollars. But leaded gas is still used,
by the way in piston driven airplane engines. That's now
the largest source of lead emissions into the air in the
US. You will observe with concern how long a useful
truth may be known and exist before it is generally
received and practiced on. When I first learned about
Thomas Midgley and Clair Patterson, I was amazed by how
much harm or how much good a single person could do to the
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