Thomas Midgley, Jr.

Born on May 18, 1889, in Beaver Falls, Pennsylvania, Thomas Midgley, Jr. was named after his father, Thomas, Sr., an English-born tinkerer who had spent his youth in Worcester, Massachusetts. The elder Midgley was employed at a steel-production plant. His mother, Hattie, was the daughter of James Ezekiel Emerson, an inventor who had made a small fortune in the California timber industry during the 1850s, before establishing the American Saw Company of Trenton, New Jersey. In 1896, the Midgley family moved to Columbus, Ohio, where Tom, Sr., found professional opportunities in the wheel-and-tire manufacturing sector.

Joined General Motors Family

Midgley graduated from Cornell University in 1911 with a mechanical engineering degree. He returned to Ohio and took a job with the National Cash Register Company (NCR) in Dayton as a draftsperson before embarking on a joint venture with his father, the Midgley Tire & Rubber Company, which failed in 1916. By then married and the father of two children, he called on one of the most promising professional contacts in his network, Charles F. Kettering, a brilliant electrical engineer who had made his name at NCR and had co-founded a research facility, the Dayton Engineering Laboratories Company, or Delco. Later a supplier/subsidiary of automotive giant General Motors (GM), Delco had developed the self-starting ignition for automobiles, thus eliminating the arduous hand-cranking required to fire up the engine. Kettering hired Midgley as an assistant at a second venture, Dayton Research Laboratories, which would also be folded into GM a few years later.

At the Dayton Research Lab Midgley worked on one of the most pressing problems for both the nascent aircraft industry—Kettering had a separate company in partnership with one of the pioneering Wright brothers—and automobile manufacturers like GM: finessing an ideal recipe for the petroleum-derived fuel products that fired internalcombustion engines and kept them running at optimum performance. One of the major challenges was “knocking,” the distinctive pinging sounds that came from inside the engine and signaled that the fuel was combining with air inside the chamber. Engine knocking also heralded the onset of sluggishness and reduced fuel efficiency.

Library of Congress, Prints & Photographs Division, Reproduction number LC-USE6-D-004065 (bw film neg.)

Library of Congress, Prints & Photographs Division, Reproduction number LC-USE6-D-004065 (bw film neg.)

Midgley began his study of this problem using a kerosene-powered Delco-Light engine, a unit designed to for use with farm equipment. One of his first breakthroughs was a quartz-operated needle as a method of measuring the internal temperature in the engine and its emission. This device and its small viewing window was later called the Midgley indicator and it helped him determine that thermodynamic pressure waves inside the engine actually produced engine knock. He began adding various compounds to gasoline to test their effectiveness, and the signature red of iodine yielded the first breakthrough in eliminating the problem. Iodine was one of the chemical elements only recently grouped in the lower-right corner of the periodic table. Midgley knew that iodine would not work as a long-term additive to petroleum-based fuel, and he began testing out combinations of other similar elements grouped near the same section of the updated table.

Poisoned by Lead

Lead seemed to be a workable additive, but it was also a metal and left behind deposits that clogged engine valves. Over time, Midgley perfected a gasoline-recipe solution that used tetraethyl lead, or TEL, a highly toxic compound first identified by a German chemist in the 1850s. TEL was oil-soluble and appeared to be an ideal fuel additive, eliminating engine knock and giving petroleum-based gasoline a higher octane rating and therefore increased efficiency. He demonstrated his findings to Kettering and GM executives in late 1921 and refined his research into the following year. In December of 1922, Midgley was awarded the William H. Nichols Medal from the American Chemical Society for his work.

Additive Proves to Be Potential Health Hazard

Midgley had already suffered lead-related health issues as a result of his laboratory work and spent several weeks recuperating in early 1923. His main lab assistant, Carroll Hochwalt, also became sick and diagnostic X-rays taken of Hochwalt showed actual lead lines, or deposits of the metal, in his bone marrow. When New York City newspapers started reporting on the growing health crisis for workers at the Deepwater, New Jersey, plant that made TEL, the problem reached national attention. A front-page New York Times story dated October 31, 1924, identified one man who “died in a straitjacket violently insane at Reconstruction Hospital …, the fifth victim of the deadly tetraethyl lead fumes generated in the Standard Oil plant.” After several more deaths and cases of lead fumes-induced psychosis were reported, officials in New Jersey and New York mobilized quickly to deem TEL a public health hazard.

Within GMCC, a corporate strategy developed to promote TEL as safe. Midgley invited reporters to his office at the Standard Oil building in New York City, where he poured TEL on his hands and claimed it was not toxic. He “was fond of this exhibition and would repeat it elsewhere, washing his hands thoroughly in the fluid and drying them on his handkerchief,” explained Kitman in the Nation, adding that Midgley also told reporters: “I'm not taking any chance whatever.” Kitman continued: “The New York World cited unbelievable dispatches from Detroit claiming that Midgley ‘frequently bathed' in TEL to prove its safety to skeptics within the industry.”

The Ethyl Corporation also cited evidence from a flawed study conducted at the company's behest by the U.S. Bureau of Mines, and it arranged for company physician to treat workers displaying early symptoms of leadinhalation poisoning, such as hallucinations of flying insects. Such symptoms were so rife that employees at the New Jersey Deepwater plant dubbed their workplace the House of Butterflies. The plant was ultimately closed, and TEL was banned for sale as a gasoline additive in New York and New Jersey. Federal legislation went into effect in 1973 that mandated a phase-out of leaded gasoline in the United States by 1986.

Shifts Focus to Coolants

Apart from his work involving leaded gasoline, Midgley continued to work at Kettering's Dayton Research Laboratories. In 1925 he began working on a new project, this time at the behest of GM's consumer-appliance unit Frigidaire. Refrigerators of the period were popular among consumers, and their ability to sustain low temperatures was achieved by a motor that pumped cooled air into the closed unit. Unfortunately, artificially produced coolants were highly unstable chemical vapors that occasionally caught fire. Again, Midgley conducted multiple laboratory experiments and in 1928 developed the world's first chlorofluorocarbon (CFC), a stable mix of chlorine, fluorine, and carbon that was marketed under the trade name Freon. Another subsidiary of GM, in conjunction with DuPont, held the patent and manufacturing rights for this gas, and Midgley was awarded the 1937 Perkin Medal for the Society of Chemical Industry for his achievement.

Midgley's promising career as an inventor-scientist was slowed by poliomyelitis, or polio, which he contracted in the late summer of 1940. A debilitating and potentially fatal infectious disease that did not yet have a preventative vaccine treatment, polio was a familiar diagnosis for thousands of Americans each year, with cases spiking in the summer months. Like U.S. President Franklin D. Roosevelt, Midgley made only a partial recovery and was hampered by mobility issues for the remainder of his life. Now in middle age, he required wheelchair and relied on technological advances to organize meetings and conferences of the National Inventors Council, which he founded shortly before the outbreak of World War II. TEL, Midgley's discovery, proved to be an enormous advantage for U.S. and British bomber aircraft during the war because the higheroctane fuel made capable longer-distance runs, increased in-air avoidance maneuverability, and supported heavier bomb payload.

Rigged Suicide Machine

Back in the late 1920s Midgley had acquired a 50-acre parcel of land in a scenic part metropolitan Columbus. The enormous estate he built there included an intercom system and a network of stone-cooled underground rooms. An inveterate tinkerer, he also perfected a bedside contraption with a leather harness into which he could maneuver his torso, and a linking system of ropes, pulleys, and counterweights allowed him to maneuver in and out of his wheelchair independent of help. His ingenuity also allowed him to choose the time and place of his death: on the morning of November 2, 1944, his wife discovered her 55-year-old, partially paralyzed husband asphyxiated by his own invention.


McGrayne, Sharon Bertsch, Prometheans in the Lab: Chemistry and the Making of the Modern World, McGraw-Hill, 2001, pp. 79–105.


Nation, March 20, 2000, p. 11.

New York Times, October 31, 1924, p. A1; April 22, 1935, p. 19.❑

(MLA 8th Edition)