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09/04/2003
The Earth and Mr. Midgley
I’m reading the book “A Short History of Nearly Everything” by
Bill Bryson. Bryson says he didn’t know a quark from a quasar
and had a powerful urge to understand the wonders of science
and to write about them in a manner that is not too technical or
demanding. He has succeeded admirably in his objective and I
recommend the book highly. I was especially intrigued by his
interweaving of the lives and accomplishments of Thomas
Midgley, Jr. and Clair Cameron Patterson.
I suspect that you’ve never heard of either of these gentlemen,
born in Beaver Falls, Pennsylvania (Midgley, in 1889) and
Mitchellville, Iowa (Patterson, in 1922). Yet, these two small
town natives contributed mightily in both highly meritorious and
highly deleterious ways to our personal and global environments.
What follows was gleaned from Bryson’s book and from articles
by George Tilton, Mary Bellis, Carla Helfferich and John
Lienhard posted on the Web sites of the National Academies
Press, About.com, and the Universities of Alaska and Houston,
respectively.
Let’s start with Patterson, who worked on the separation of
uranium isotopes for the atom bomb while working at Oak Ridge
during World War II. (Remember, isotopes of an element have a
different numbers of neutrons in their nuclei, i.e., they have
different weights.) Uranium is unstable, decaying over time to
form lead as one of the products. If one has a rock and measures
the amounts of uranium and lead isotopes, and if one knows the
rates of decay (the half-lives), one can calculate the age of the
rock. After the war Patterson returned to the University of
Chicago to join in a collaborative effort to date ancient rocks and
meteorites.
Patterson’s part of the project was to concentrate on measuring
the lead isotopes. It had been suggested that if one could
measure the amounts of lead isotopes in certain meteorites, this
would give the composition of lead in the material present during
or just before the formation of earth itself. Patterson’s objective
was to measure the age of our planet Earth.
So, Clair Patterson started analyzing rocks from all over the
world. At the time, the earth’s age was thought to be about 3
billion years. Measuring small amounts of lead was not easy.
His task was complicated by beginning his work in a dusty lab in
one of the oldest buildings on the Chicago campus and it was not
easy to avoid contamination of his samples by lead in the
environment. He later moved to the California Institute of
Technology, where he built clean room facilities that set new
standards for avoiding contamination. In 1953, he analyzed the
so-called Canyon Diablo meteorite and came up with the age of
the earth as 4.5 billion years. Later data on other meteorites fine-
tuned the age to 4.55 billion years, the accepted figure today.
Patterson next set out to apply his expertise to study the
geological history of the earth. But first he wanted to establish
more precisely the relative amounts of each isotope of lead in
“modern” lead. He started off measuring these ratios in ocean
sediments and was disturbed by the results.
Now let’s step back in time and talk about Tom Midgley. After
getting his Ph.D. in engineering from Cornell, he joined Charles
Kettering’s lab in Dayton, Ohio in 1916. Kettering was later to
become a vice president of General Motors and was to describe
Midgley as his “greatest discovery”. Kettering had a kerosene
engine that he was selling to farmers to power home lighting
systems. (I can remember as a kid visiting my aunt and uncle’s
farm in Maryland in the 1930s and gathering in the evening by
the light of “coal oil” (kerosene) lamps.) However, the motor
knocked like crazy and Midgley was assigned to find something
to remedy the situation. Iodine helped, but wasn’t the answer.
Several years later, as a GM employee, Midgley found that the
compound tetraethyl lead stopped engine knock when added to
gasoline. The toxic properties of lead were well known and the
less frightening trade name of “Ethyl” was adopted. In 1923, the
Ethyl Gasoline Corporation was formed as a joint venture of
GM, Du Pont and Standard Oil to market the product, which was
a huge hit in the emerging automotive society. This was an era
when lead pipes were common. Bryson points out that the word
“plumbing” comes from the Latin word for lead, “plumbum”.
Lead solder, lead in toothpaste tubes, lead in paint – lead was
everywhere.
Back to the disturbed Patterson. Without going into details, his
studies on the oceans didn’t add up and he began to think that
there was a lot of lead in the environment coming from human
activities. He coauthored a 1963 paper showing that the amount
of lead in deep ocean water was 3 to 10 times less than the
amount of lead in surface water. By 1965, Patterson was in high
gear, warning of the health dangers of lead and challenging the
prevailing view that the amount of lead in the environment was
only a factor of two higher than in pre-lead days. He concluded
that the blood levels in some Americans were 100 times the
“natural” level. He began lobbying public figures like Governor
Pat Brown of California, Senator Edmund Muskie and drew the
support of Ralph Nader.
Patterson’s warnings drew responses from industrial toxicology
experts as being “rabble rousing” and without merit. He then
embarked on a journey to Greenland to dig up snow cores and
analyze them for lead. By 1970, he and his colleagues had
completed studies on cores from both Greenland and Antarctica
and the results were startling. The amounts of lead in the
Greenland cores laid down in pre-industrial times were over 100
times less than in the later cores. And most of the lead was
deposited over the past century. The Antarctic cores showed a
similar increase in lead but not nearly as much as in Greenland,
as would be expected with most of industrial activity and
vehicular traffic being in the Northern Hemisphere.
By 1973, the EPA started the phasing out of leaded gasoline.
Patterson turned his attention to lead in foods. His and his co-
workers’ data on lead in canned fish helped stop the practice of
sealing cans with lead solders. But let’s go back to 1930 and
Tom Midgley. GM had a Frigidaire division and the refrigerants
in those days were toxic compounds such as ammonia, methyl
chloride and sulfur dioxide. Kettering wanted a safer
regfrigerant and gave Midgley the job.
Midgley was good! In only three days he came up with Freon,
the first of the chlorofluorocarbon (CFC) refrigerants. Was it
safe and nonflammable? Midgley demonstrated this by inhaling
some of the stuff and exhaling it, snuffing out a candle! Like his
“ethyl”, the Freon was an immediate success and the world was
grateful, incorporating CFCs in air conditioners, freezers, coolers
and even as propellants in aerosol cans containing products from
deodorants to shaving cream. But you know the rest of the story.
Someone found a hole in the ozone layer over Antarctica and the
CFCs were the culprit.
Once again, there was a global threat occasioned by a Tom
Midgley invention. The CFCs were banned or drastically
curtailed in most countries and only recently are there finally
indications that the ozone layer is or will begin restoring itself in
the not too distant future.
Midgley never knew of the uproar his inventions would cause.
He contracted polio when he was 51 and, ever the inventor, came
up with a harness of some sort that he used to help to get himself
out of bed. On November 2, 1944 he got tangled up in the
contraption and strangled himself! Ironically, I found in
Lienhard’s article on the University of Houston’s Web site the
statement that the catalytic converters that were developed to
handle other pollutants in automotive emissions “strangled on
leaded gas, so we gave up lead.” Patterson’s fight to eliminate
lead apparently was helped by very practical considerations.
How to view Midgley’s inventions? On the plus side, the lead
additive helped to advance the continued development of the
internal combustion engine. On the minus side, who knows how
many illnesses or deaths were due to lead contamination from
auto emissions? Concerning the CFCs, undoubtedly lives were
saved when CFCs were substituted for the dangerous refrigerants
used previously. I have written of my own near-death experience
as a child when an ammonia plant blew up in our local ice cream
factory and killed two young girls. (If you missed that column, I
would have been in the factory at the time were it not for our
family’s decision that I should pick up Breyer’s ice cream that
day.) On the other hand, who knows what the consequences
have been from the depletion of ozone in our atmosphere? Life
is full of unanswered questions.
Allen F. Bortrum
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