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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
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