Thomas Midgley Jr. (1889–1944)
Thomas Midgley Jr. was an American mechanical and chemical engineer whose inventions profoundly influenced 20th-century industry and the global environment. He is best known for developing tetraethyllead (TEL) as an antiknock additive for gasoline and for co-developing chlorofluorocarbon (CFC) refrigerants, notably Freon-12. While these innovations initially addressed pressing technical problems—engine knocking and the safety of early refrigerants—they later proved to have severe public-health and environmental consequences.
Early Life and Education
Born on May 18, 1889, in Beaver Falls, Pennsylvania, and raised in Ohio, Midgley was the son of an inventor. He earned a degree in mechanical engineering from Cornell University in 1911.
Career and Major Innovations
In 1916 Midgley joined Charles F. Kettering’s research team at Dayton Engineering Laboratories Company (Delco), later associated with General Motors. Investigating engine knock, he identified tetraethyllead in 1921 as an effective antiknock compound, enabling higher-compression engines and improved performance. Commercialized in 1923 through the Ethyl Corporation, TEL’s use led to widespread lead emissions and documented cases of worker and community poisoning.
Turning to refrigeration in the late 1920s, Midgley and colleagues, including Albert Leon Henne, synthesized stable halogenated hydrocarbons. In 1928 they introduced dichlorodifluoromethane (CFC-12, marketed as Freon-12), a nonflammable, low-toxicity refrigerant and propellant that rapidly displaced more dangerous alternatives. Decades later, CFCs were found to deplete the stratospheric ozone layer, prompting international regulation and phase-outs.
Later Life and Death
Midgley experienced lead poisoning during his work with TEL and contracted poliomyelitis in 1940, which left him partially disabled. He devised a rope-and-pulley hoist to assist with mobility and died by accidental strangulation in Worthington, Ohio, on November 2, 1944.
Awards and Honors
- Perkin Medal (1937)
- Priestley Medal (1941)
- Willard Gibbs Award (1942)
Legacy
Midgley’s career illustrates the unintended consequences of technological solutions: innovations that solved immediate industrial challenges later produced profound harms. Leaded gasoline began to be phased out in the 1970s, and CFCs were curtailed globally under the Montreal Protocol. He remains a central, controversial figure in the history of industrial chemistry and environmental change.