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Thomas Midgley, Jr.

Thomas Midgley, Jr.
Born18 May 1889
Beaver Falls, Pennsylvania, USA
Died2 November 1944
Residence USA
Nationality American
Fieldmechanical engineer / chemist
Alma materCornell University
Known forLeaded petrol and CFCs
Notable prizesNichols Medal (1922)
Perkins Medal (1937)
Priestley Medal (1941)
William Gibbs Medal (1942)

Thomas Midgley, Jr. (May 18, 1889 – November 2, 1944), was an American mechanical engineer turned chemist. He developed both the tetra-ethyl lead (TEL) additive to gasoline and chlorofluorocarbons (CFCs), and held over a hundred patents. While lauded at the time for his discoveries, today his legacy is seen as far more mixed considering the serious negative environmental impacts of these innovations. One historian remarked that Midgley "had more impact on the atmosphere than any other single organism in Earth history." [1]


Early life

Midgley was born in Beaver Falls, Pennsylvania, to a father who was also an inventor. He grew up in Columbus, Ohio, and graduated from Cornell University in 1911 with a degree in mechanical engineering.[2]

Discovery of Ethyl

While working for Dayton Research Laboratories (a subsidiary of General Motors) in December of 1921, Midgley discovered that the addition of tetra-ethyl lead (TEL) to gasoline prevented internal combustion engines from "knocking". The company dubbed the substance "Ethyl", avoiding all mention of lead in reports and advertising. Oil companies and auto makers, especially GM which owned the patent, strenuously promoted leaded fuel as an alternative to ethanol or ethanol-blended fuels, on which they could make very little profit.[3]

In December 1922, the American Chemical Society awarded Midgley the William H. Nichols Medal, the first of several major awards he won during his career.[2]

The subsequent addition of lead to gasoline eventually resulted in the release of huge amounts of lead into the atmosphere, causing health problems around the world. Midgley himself had to take a prolonged vacation to cure himself of lead poisoning. "After about a year's work in organic lead," he wrote in January 1923, "I find that my lungs have been affected and that it is necessary to drop all work and get a large supply of fresh air." He repaired to Miami.[4]

In April 1923, GM created the General Motors Chemical Company to supervise the production of TEL by the DuPont company, and placed Charles Kettering as president and Midgley as vice president. However, after two deaths and several cases of lead poisoning at the TEL prototype plant in Dayton, Ohio, the staff at Dayton was said in 1924 to be "depressed to the point of considering giving up the whole tetraethyl lead program."[4] Over the course of the next year, eight more people would die at DuPont's Deepwater, New Jersey plant.[4]

Dissatisfied with the speed of DuPont's production using their "bromide process", GM and Standard Oil created the Ethyl Gasoline Corporation in 1924, and built a new TEL plant using a more dangerous high-temperature "ethyl chloride process" at the Bayway Refinery in New Jersey.[4] Within the first two months of its operation, the Bayway plant was plagued by more cases of lead poisoning, hallucinations, insanity, and then five deaths in quick succession. On October 30, Midgley participated in a press conference to demonstrate the "safety" of contact with the substance. In this demonstration, he poured tetra-ethyl lead over his hands, then placed a bottle of the chemical under his nose and breathed it in for sixty seconds, declaring that he could do this every day without succumbing to any problems whatsoever.[3][5] However, the plant was decisively shut down by the State of New Jersey a few days later, and Standard was forbidden to manufacture TEL there again without state permission.

Midgley was relieved of his position as vice president of GMCC in April of 1925, reportedly due to his inexperience in organizational matters, but he remained an employee of GM.[3]

Discovery of Freon

In 1930, General Motors charged Midgley with developing a non-toxic and safe refrigerant for household appliances. He discovered dichlorodifluoromethane, a chlorinated fluorocarbon (CFC) which he dubbed Freon. CFCs replaced the various toxic or explosive substances previously used as the working fluid in heat pumps and refrigerators. CFCs were also used as propellants in aerosol spray cans, metered dose inhalers (asthma inhalers), and more. He was awarded the Perkins Medal in 1937 for this work.

In 1941, the American Chemical Society gave Midgley its highest award, the Priestley Medal, and followed up with the William Gibbs Medal in 1942. He also held two honorary degrees, and was elected to the National Academy of Sciences. In 1944, he was president and chairman of the American Chemical Society.[2]


In 1940, he contracted polio at the age of 51, which left him severely disabled. This led him to devise an elaborate system of strings and pulleys to lift him from bed. This system was the eventual cause of his death when he was accidentally entangled in the ropes of this device and died of suffocation at the age of 55.[6] [7]Midgley died before the effect of CFCs upon the ozone layer became widely known.

Standards to phase out leaded gasoline were first implemented in the United States in 1973, and in 1996, the Clean Air Act banned the sale of leaded fuel for use in on-road vehicles. However, usage will remain legal in the U.S. for aircraft, racing cars, farm equipment, and marine engines until 2008. Leaded gasoline is still common in South America, Africa, and some parts of Asia and the Middle East.

The Montreal Protocol forbade major countries to produce CFCs, and their production is set to cease on the rest of the planet by 2010. Health services and pharmacological companies have been replacing inhalers which use CFCs with devices that do not. Unfortunately, CFC-based heat-pumps are significantly more efficient than any of their environmentally safe alternatives, such as those which use alkanes and haloalkanes (also known as hydrofluorocarbons or HFCs). This provides great incentive for those who refuse to believe the environmental danger of CFCs to resist the banning of the substances. It has also been suggested that there is a serious loophole in the current ban in production, in that affected countries can still import and use CFCs manufactured in other countries outside the legislation.


  1. ^ McNeill, J.R. Something New Under the Sun: An Environmental History of the Twentieth-Century World (2001) New York: Norton, xxvi, 421 pp. (as reviewed in the Journal of Political Ecology)
  2. ^ a b c Inventors Hall of Fame Profile: Thomas Midgely
  3. ^ a b c "The Secret History of Lead" The Nation, March 20, 2000
  4. ^ a b c d Kovarik, Bill. "Charles F. Kettering and the 1921 Discovery of Tetraethyl Lead In the Context of Technological Alternatives", presented to the Society of Automotive Engineers Fuels & Lubricants Conference, Baltimore, Maryland., 1994; revised in 1999.
  5. ^ Markowitz, Gerald and Rosner, David. Deceit and Denial: The Deadly Politics of Industrial Pollution. Berkeley, California: University of California Press, 2002
  6. ^ Bryson, Bill. A Short History of Nearly Everything. (2003) Broadway Books, USA. ISBN 0-385-66004-9
  7. ^ Staff of Damn Interesting. The Ethyl-Poisoned Earth. Retrieved on 2007-12-08.

NAME Midgley, Thomas, Jr.
SHORT DESCRIPTION American chemist
DATE OF BIRTH 18 May 1889
PLACE OF BIRTH Beaver Falls, Pennsylvania, USA
DATE OF DEATH 2 November 1944
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Thomas_Midgley,_Jr.". A list of authors is available in Wikipedia.
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