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{{Short description|American chemist and engineer (1889–1944)}}
{{Use mdy dates|date=May 2025}}
{{Infobox scientist
| name = Thomas Midgley Jr.
| image = Portrait of Thomas Midgley Jr..jpg
| caption = Midgley {{circa|1930s–1940s}}
| birth_date = {{birth date|1889|05|18|mf=y}}
| birth_place = [[Beaver Falls, Pennsylvania]], U.S.
| death_date = {{death date and age|1944|11|02|1889|05|18|mf=y}}
| death_place = [[Worthington, Ohio]], U.S.
| spouse = {{marriage|Carrie Reynolds|1911}}
| field = {{hlist|[[Mechanical engineering]]|[[chemical engineering]]}}
| alma_mater = [[Cornell University]]
| known_for = {{hlist|[[Leaded gasoline]]|[[Chlorofluorocarbon|CFCs]]}}
| prizes = {{unbulleted list |[[William H. Nichols Medal]] (1922)|[[Edward Longstreth Medal|Longstreth Medal]] (1925)<ref>{{cite web |url=http://www.fi.edu/winners/show_results.faw?gs=&ln=&fn=&keyword=&subject=&award=LONG+&sy=1924&ey=1926&name=Submit |title=Franklin Laureate Database – Edward Longstreth Medal 1925 Laureates |publisher=[[Franklin Institute]] |access-date=November 18, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20131015080435/http://www.fi.edu/winners/show_results.faw?gs=&ln=&fn=&keyword=&subject=&award=LONG%2B&sy=1924&ey=1926&name=Submit |archive-date=October 15, 2013 }}</ref>|[[Perkin Medal]] (1937)|[[Priestley Medal]] (1941)|[[Willard Gibbs Award]] (1942)}}
}}

'''Thomas Midgley Jr.''' (May 18, 1889&nbsp;– November 2, 1944) was an American [[Mechanical engineering|mechanical]] and [[chemical engineer]]. He played a major role in developing [[Tetraethyllead|leaded gasoline]] (tetraethyl lead) and some of the first [[chlorofluorocarbon]]s (CFCs), better known in the United States by the brand name [[Freon]]; both products were later banned from common use due to their harmful impact on human health and the [[Human impact on the environment|environment]]. He was granted more than 100 [[patent|patents]] over the course of his career.<ref name="Fame"/>

Midgley contracted [[polio]] in 1940 and was left disabled; in 1944, he was found strangled to death by a device he devised to allow him to get out of bed unassisted. It is often reported that he had been accidentally [[List of inventors killed by their own invention|killed by his own invention]], but his death was declared by the coroner to be a [[suicide]].

While the harmful effects of CFCs were not appreciated until decades after Midgley's death, tetraethyl lead was known to be acutely toxic by those involved in the development of leaded gasoline. This included Midgley, who publicly insisted that there was nonetheless no health hazard posed by the use of leaded gasoline in internal combustion engines.<ref name="Secret" />

== Early life ==
Thomas Midgley Jr. was born in [[Beaver Falls, Pennsylvania|Beaver Falls]],  [[Pennsylvania]] on May 18, 1889, the son of Hattie Louise (née Emerson) (1865 – 1950) and Thomas Midgley Sr. (1840 – 1934). His family had a history of inventing; his father was an inventor in the field of [[car|automobile]] [[tire|tires]] while his maternal grandfather, James Emerson, invented the inserted tooth [[saw]]. He grew up in [[Columbus, Ohio|Columbus]],  [[Ohio]] and graduated from [[Cornell University]] in 1911 with a degree in mechanical engineering.<ref name="Fame">{{cite web |work=invent.org |publisher=[[National Inventors Hall of Fame]] |title=Thomas Midgley, Jr. |date=May 17, 2023 |url=https://www.invent.org/inductees/thomas-midgley-jr}}</ref><ref name=NAS_bio>{{cite journal | url = http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/midgley-thomas.pdf| publisher= National Academy of Sciences| journal = Biographical Memoirs | volume = 24 | pages = 359–380 | last = Kettering | first = Charles F. |author-link=Charles F. Kettering | title = Thomas Midgley Jr. 1889–1944 }}</ref>

Early on, Midgley had a penchant for finding useful applications for known substances. In [[High school in the United States|high school]], he used the chewed bark of [[slippery elm]] trees to give [[Baseball (ball)|baseballs]] a more curved trajectory, a practice professional players would later pick up. Later in life, he was known to always carry a copy of the [[periodic table]], his main tool in the search for the substance that would mark his breakthrough invention.<ref name="CNN Prisco">{{cite web |last1=Prisco |first1=Jacopo |title=Once celebrated, an inventor's breakthroughs are now viewed as disasters — and the world is still recovering |url=https://www.cnn.com/2024/05/24/world/thomas-midgley-jr-leaded-gas-freon-scn/index.html |website=cnn.com |date=May 24, 2024 |publisher=Cable News Network |access-date=May 27, 2024}}</ref>

==Career==
=== Leaded gasoline ===
[[File:EthylCorporationSign.jpg|thumb|right|Sign on an antique gasoline pump advertising the [[Tetraethyllead|TEL]] anti-knock compound Ethyl, a [[gasoline additive]]]]

In 1916, Midgley began working at [[General Motors]]. In December 1921, while working under the direction of [[Charles F. Kettering|Charles Kettering]] at [[Delco Electronics|Dayton Research Laboratories]], a subsidiary of General Motors, he discovered (after discarding [[tellurium]] due to the difficult-to-eradicate smell) that the addition of [[tetraethyllead]] (TEL) to gasoline prevented [[Engine knocking|knocking]] in [[internal combustion engine]]s.<ref>Loeb, A.P., "Birth of the Kettering Doctrine: Fordism, Sloanism and Tetraethyl Lead," ''Business and Economic History'', Vol. 24, No. 2, Fall 1995.</ref> The company named the substance "Ethyl", avoiding all mention of lead in reports and advertising. [[Petroleum industry|Oil companies]] and [[Automotive industry|automobile manufacturers]] (especially General Motors, which owned the patent jointly filed by Kettering and Midgley) promoted the TEL additive as an inexpensive alternative superior to [[ethanol]] or [[Ethanol fuel|ethanol-blended fuels]], on which they could make very little profit.<ref name="Jacobson">{{cite book |last1=Jacobson |first1=Mark Z. |title=Atmospheric pollution : history, science, and regulation |date=2002 |publisher=Cambridge University Press |isbn=0521010446 |pages=75–80 |url=https://books.google.com/books?id=bveEPjMxP3cC&pg=PA76}}</ref><ref name="disaster">{{cite journal |last1=Kovarik |first1=William |title=Ethyl-leaded gasoline: How a classic occupational disease became an international public health disaster |journal=International Journal of Occupational and Environmental Health |date=2005 |volume=11 |issue=4 |pages=384–397 |url=https://pdfs.semanticscholar.org/5ef4/a42a4a5940ef6adf04aa1912147097aa3363.pdf |archive-url=https://web.archive.org/web/20180617165801/https://pdfs.semanticscholar.org/5ef4/a42a4a5940ef6adf04aa1912147097aa3363.pdf |url-status=dead |archive-date=June 17, 2018 |access-date=October 7, 2018 |doi=10.1179/oeh.2005.11.4.384|pmid=16350473 |s2cid=44633845 }}</ref><ref name="Secret">{{citation |last=Kitman |first=Jamie Lincoln |date=March 2, 2000 |url=http://www.thenation.com/article/archive/secret-history-lead |title=The Secret History of Lead |website=The Nation |issn=0027-8378 |access-date=October 19, 2024}}</ref> In December 1922, the [[American Chemical Society]] awarded Midgley the 1923 [[William H. Nichols Medal|Nichols Medal]] for the "Use of Anti-Knock Compounds in Motor Fuels".<ref name="Nichols">[http://newyorkacs.org/nicholsmedalists.html Nichols Medalists]</ref> This was the first of several major awards he earned during his career.<ref name="Fame" />

In 1923, Midgley took a long vacation in [[Miami]] to cure himself of [[lead poisoning]]. He said, "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."<ref name=Kovarik>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.</ref> That year, General Motors created the General Motors Chemical Company (GMCC) to supervise the production of TEL by the [[DuPont]] company. Kettering was elected as president with 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".<ref name="disaster"/> Over the course of the next year, eight more people died at DuPont's plant in [[Deepwater, New Jersey|Deepwater]], [[New Jersey]].<ref name=Kovarik/> In 1924, dissatisfied with the speed of DuPont's TEL production using the "[[bromide]] process", General Motors and the Standard Oil Company of New Jersey (now known as [[ExxonMobil]]) created the [[Ethyl Corporation|Ethyl Gasoline Corporation]] to produce and market TEL. Ethyl Corporation built a new [[chemical plant]] using a high-temperature [[Chloroethane|ethyl chloride]] process at the [[Bayway Refinery]] in New Jersey.<ref name=Kovarik/> However, within the first two months of its operation, the new plant was plagued by more cases of lead poisoning, [[hallucination]]s, [[insanity]], and five deaths.<ref name=Secret/>

The risks associated with [[Lead_poisoning#History|exposure to lead]] have been known at least since the [[2nd century BC|2nd century&nbsp;BC]],<ref name=Dap2014>{{cite journal | vauthors = Dapul H, Laraque D | title = Lead poisoning in children | journal = Advances in Pediatrics | volume = 61 | issue = 1 | pages = 313–33 | date = August 2014 | pmid = 25037135 | doi = 10.1016/j.yapd.2014.04.004 }}</ref> while efforts to limit lead's use date back to at least the 16th century.<ref name=Need2004>{{cite journal | vauthors = Needleman H | title = Lead poisoning | journal = Annual Review of Medicine | volume = 55 | pages = 209–22 | year = 2004 | pmid = 14746518 | doi = 10.1146/annurev.med.55.091902.103653 }}</ref><ref name=Dap2014/><ref name="NeedlemanDentineLead">{{cite journal |last1=Needleman |first1=Herbert L. |last2=Gunnoe |first2=Charles |last3=Leviton |first3=Alan |last4=Reed |first4=Robert |last5=Peresie |first5=Henry |last6=Maher |first6=Cornelius |last7=Barrett |first7=Peter |title=Deficits in Psychologic and Classroom Performance of Children with Elevated Dentine Lead Levels |journal=New England Journal of Medicine |date=March 29, 1979 |volume=300 |issue=13 |pages=689–695 |doi=10.1056/NEJM197903293001301 |pmid=763299 |access-date=November 17, 2020|url=https://www.nejm.org/doi/full/10.1056/NEJM197903293001301|url-access=subscription }}</ref> Midgley experienced lead poisoning himself, and was warned about the risk of lead poisoning from TEL as early as 1922.<ref>{{cite journal |last1=Seyferth |first1=Dietmar |title=The Rise and Fall of Tetraethyllead. 2. |journal=Organometallics |date=December 1, 2003 |volume=22 |issue=25 |pages=5154–5178 |doi=10.1021/om030621b |doi-access=free}} and {{erratum|doi=10.1021/om0343925|doi-access=free|checked=yes}}</ref> Midgley well knew the hazards of lead.  He investigated whether the risks, both in production and use, could be managed. Testing on the exhaust was completed, which he used to support the idea that 1 part tetraethyl lead per 1300 of gasoline could safely be used.<ref>{{cite journal | last1=Midgley | first1=Thomas | title= Tetraethyl Lead Poison Hazards | journal= Industrial and Engineering Chemistry | date= August 1, 1925 | volume= 17 | issue=8 |pages = 827–828 | doi=10.1021/ie50188a020 |quote="After mixing tetraethyl lead with gasoline, no great precaution need be exercised, the ratio being 1 part tetraethyl lead to 1300 of gasoline. From this point on no health hazards actually exist unless the gasoline is used very abnormally for purposes for which it was not intended."}}</ref>  After the initial worker exposures, controls were developed to allow the process to operate safely. Leaded gasoline use grew exponentially. The cumulative chronic impacts of environmental lead were grossly underestimated.

On October 30, 1924, Midgley participated in a [[news conference|press conference]] to demonstrate the apparent safety of TEL, in which he poured TEL over his hands, placed a bottle of the chemical under his nose, and inhaled its [[vapor]] for sixty seconds, declaring that he could do this every day without succumbing to any problems.<ref name=Secret/><ref name=Deceit>Markowitz, Gerald and Rosner, David. ''Deceit and Denial: The Deadly Politics of Industrial Pollution''. Berkeley, California: University of California Press, 2002</ref><ref>{{Cite web |last=Prisco |first=Jacopo |date=May 24, 2024 |title=Once celebrated, an inventor's breakthroughs are now viewed as disasters — and the world is still recovering |url=https://www.cnn.com/2024/05/24/world/thomas-midgley-jr-leaded-gas-freon-scn/index.html |access-date=May 26, 2024 |website=CNN |language=en}}</ref> However, the state of New Jersey ordered the Bayway plant to be closed a few days later, and Jersey Standard was forbidden to manufacture TEL again without state permission. Production was restarted in 1926 after intervention by the federal government. High-octane fuel, enabled by lead, was important to the military. Midgley later took a leave of absence from work after being diagnosed with lead poisoning.<ref>[https://www.pbs.org/wgbh/americanexperience/films/poisoners/player/ The Poisoner's Handbook] {{Webarchive|url=https://web.archive.org/web/20161227032106/http://www.pbs.org/wgbh/americanexperience/films/poisoners/player/ |date=December 27, 2016 }} ''[[American Experience]]'' at 51:48 January 2014</ref>  He was relieved of his position as vice president of GMCC in April 1925, reportedly due to his inexperience in organizational matters, but he remained an employee of General Motors.<ref name=Secret/>

===Freon ===
In the late 1920s, [[air conditioning]] and [[refrigeration]] systems employed compounds such as [[ammonia]] (NH<sub>3</sub>), [[chloromethane]] (CH<sub>3</sub>Cl), [[propane]], [[methyl formate]] (HCO<sub>2</sub>CH<sub>3</sub>), and [[sulfur dioxide]] (SO<sub>2</sub>) as [[refrigerant]]s. Though effective, these were [[Toxicity|toxic]], [[Flammability|flammable]], or [[Explosive material|explosive]]. The [[Frigidaire]] division of General Motors, at that time a leading manufacturer of such systems, sought a non-toxic, non-flammable alternative to these refrigerants.<ref name=Sneader2005>{{cite book |title=Drug discovery: a history |chapter=Chapter 8: Systematic medicine |pages=74–87 |last=Sneader |first=Walter |publisher=John Wiley and Sons |location=Chichester, England |year=2005 |isbn=978-0-471-89980-8 |url=https://books.google.com/books?id=mYQxRY9umjcC&q=Drug+Discovery+history |access-date=September 13, 2010}}</ref>

Midgley, working with [[Albert Leon Henne]], soon narrowed his focus to alkyl halides (the combination of carbon chains and [[halogen]]s), which were known to be highly [[Volatility (chemistry)|volatile]] (a requirement for a refrigerant) and also [[chemically inert]]. They eventually settled on the concept of [[halogenation|incorporating fluorine]] into a [[hydrocarbon]]. They rejected the assumption that such compounds would be toxic, believing that the stability of the [[carbon–fluorine bond]] would be sufficient to prevent the release of [[hydrogen fluoride]] or other potential [[Chemical decomposition|breakdown products]].<ref name=Sneader2005/> The team eventually synthesized [[dichlorodifluoromethane]],<ref>{{cite journal | doi = 10.1021/ie50245a031| title = Organic Fluorides as Refrigerants1| journal = Industrial & Engineering Chemistry| volume = 22| issue = 5| pages = 542| year = 1930| last1 = Midgley| first1 = Thomas| last2 = Henne| first2 = Albert L.}}</ref> the first [[chlorofluorocarbon]] (CFC), which they named "[[Freon]]".<ref name=Sneader2005/><ref>{{cite journal | doi = 10.1021/ie50270a008| title = Freon, a Refrigerant| journal = Industrial & Engineering Chemistry| volume = 24| issue = 6| pages = 620–623| year = 1932| last1 = Thompson| first1 = R. J.}}</ref>  This compound is more commonly referred to today as "Freon 12", or "[[Dichlorodifluoromethane|R12]]".<ref>{{cite journal | doi = 10.1021/ed039p361| title = Freon: Thomas Midgley and Albert L. Henne| journal = Journal of Chemical Education| volume = 39| issue = 7| pages = 361| year = 1962| last1 = Garrett| first1 = Alfred B.| bibcode = 1962JChEd..39..361G}}</ref>

Freon and other CFCs soon largely replaced other refrigerants, but also had other applications. A notable example was their use as a propellant in [[aerosol]] products and [[asthma]] inhalers.<ref>{{cite journal |journal=[[Air & Waste Management Association|Journal of the Air & Waste Management Association]] |title=Stratospheric ozone, global warming, and the principle of unintended consequences—An ongoing science and policy success story |last1=Andersen |first1=Stephen O. |author1-link=Stephen O. Andersen |last2=Halberstadt |first2=Marcel L. |last3=Borgford-Parnell |first3=Nathan |year=2013 |volume=63 |issue=6 |pages=607–647 |doi=10.1080/10962247.2013.791349 |pmid=23858990 |bibcode=2013JAWMA..63..607A |doi-access=free |via=[[Taylor & Francis]] Online |quote=CFCs and HCFCs rapidly replaced other refrigerants in all but applications where companies accepted the increased risk of flammable and toxic refrigerant releases or in applications where the existing technologies were more energy efficient.}}</ref> The [[Society of Chemical Industry]] awarded Midgley the [[Perkin Medal]] in 1937 for this work.<ref>{{cite journal |journal=Refrigerating Engineering |date=January 1937 |volume=33 |issue=1 |title=Will Award Perkin Medal Jan. 8 to Thomas Midgley, Jr. |page=54 |url=https://books.google.com/books?id=WpQpAQAAMAAJ&pg=PA54 |via=[[Google Books]]}}</ref> In 1941, the [[American Chemical Society]] gave Midgley its highest award, the [[Priestley Medal]].<ref name=Priestley>[https://web.archive.org/web/20160304121719/https://pubs.acs.org/cen/acsnews/86/8614acsnews3.html The Priestley Medalists, 1923-2008] – [[American Chemical Society]]</ref> This was followed by the [[Willard Gibbs Award]] in 1942. He also held two [[honorary degree]]s and was elected to the [[United States National Academy of Sciences]]. In 1944, he was elected president and chairman of the American Chemical Society.<ref name=Fame/>

== Death ==
In 1940, at the age of 51, Midgley contracted polio and was left severely disabled. He devised an elaborate system of ropes and pulleys to lift himself out of bed. On November 2, 1944, at the age of 55, he was found dead at his home in [[Worthington, Ohio]]. He had been [[List of inventors killed by their own invention|killed by his own device]] after he became entangled in it and died of strangulation.<ref name="Bryson">{{cite book | author-last= Bryson | author-first= Bill| author-link= Bill Bryson| title= A Short History of Nearly Everything |publisher= [[Transworld Publishers]] |date=2004| orig-year=First published 2003 | isbn=0-552-99704-8| edition= Black Swan paperback| page= 196 | title-link= A Short History of Nearly Everything}}</ref><ref name=Bellows2007>{{cite news |url=http://www.damninteresting.com/?p=932 |title=The Ethyl-Poisoned Earth |last=Bellows |first=Alan |date=December 8, 2007}}</ref><ref name=Milestones>[https://web.archive.org/web/20081214232532/http://www.time.com/time/magazine/article/0,9171,801605,00.html Milestones, Nov. 13, 1944] ''[[Time (magazine)|Time]]'', November 13, 1944.</ref><ref name="giunta">{{cite journal |last1=Giunta |first1=Carmen |title=Thomas Midgley, Jr., and The Invention of Chlorofluorocarbon Refrigerants: It Ain't Necessarily So |journal=[[Bulletin for the History of Chemistry]] |date=2006 |volume=31 |issue=2 |pages=66–74 |doi=10.70359/bhc2006v031p066 |url=http://acshist.scs.illinois.edu/bulletin_open_access/v31-2/v31-2%20p66-74.pdf |archive-url=https://web.archive.org/web/20190413043223/http://acshist.scs.illinois.edu/bulletin_open_access/v31-2/v31-2%20p66-74.pdf |archive-date=April 13, 2019 |url-status=live |access-date=January 28, 2023}}</ref> His death was ruled a suicide by the coroner.<ref>{{cite news |url=https://www.newspapers.com/article/the-dayton-herald-obituary-for-thomas-m/148129966/ |author=<!--Staff writer(s); no by-line.--> |title=Midgley's Death Termed Suicide |newspaper=Dayton Herald (Ohio) |page=28 |date=November 10, 1944 |access-date=May 26, 2024 }}</ref>
He left behind a widow, Carrie M. Reynolds from [[Delaware, Ohio]], whom he had married on August 3, 1911.<ref name="NAS_bio" /> 

== Legacy ==
Midgley's legacy is tied in with the [[Environmental degradation|negative environmental impact]] of [[Tetraethyllead|leaded gasoline]] and [[freon]].<ref name=Knight-2014>{{cite news |url=https://www.bbc.co.uk/news/magazine-29568505 |title=The fatal attraction of lead |author=Laurence Knight |date=October 12, 2014 |work=BBC News |access-date=August 23, 2016}}</ref> [[Environmental history|Environmental historian]] [[J. R. McNeill]] opined that Midgley "had more adverse impact on the atmosphere than any other single organism in Earth's history",<ref name=McNeill>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 by [[Michael Bess]] in the {{cite web |url=http://dizzy.library.arizona.edu/ej/jpe/volume_9/1101bess.html |title=''Journal of Political Ecology'' |access-date=October 10, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20040328013401/http://dizzy.library.arizona.edu/ej/jpe/volume_9/1101bess.html |archive-date=March 28, 2004 }})</ref> and [[Bill Bryson]] remarked that Midgley possessed "an instinct for the regrettable that was almost uncanny".<ref name="Bryson pg 195">{{cite book | author-last= Bryson | author-first= Bill| author-link= Bill Bryson| title= A Short History of Nearly Everything |publisher= [[Transworld Publishers]] |date=2004| orig-year=First published 2003 | isbn=0-552-99704-8| edition= Black Swan paperback | page=195 | title-link= A Short History of Nearly Everything}}</ref> [[Fred Pearce]], writing for ''[[New Scientist]]'', described Midgley as a "one-man environmental disaster".<ref name="Pearce">{{cite journal |last1=Pearce |first1=Fred |author1-link=Fred Pearce |date=June 7, 2017 |title=Inventor hero was a one-man environmental disaster |url=https://www.newscientist.com/article/mg23431290-800-inventor-hero-was-a-oneman-environmental-disaster |journal=New Scientist |doi=10.1016/S0262-4079(17)31121-1 |access-date=April 25, 2022|url-access=subscription }}</ref>

Use of leaded gasoline, which he invented, released large quantities of lead into the [[Atmosphere of Earth|atmosphere]] all over the world.<ref name=Knight-2014/> High [[Lead poisoning#Epidemiology|atmospheric lead]] levels have been linked with serious long-term health problems from childhood, including neurological impairment,<ref name=CABS>{{cite web |publisher=Agency for Toxic Substances and Disease Registry/Division of Toxicology and Environmental Medicine |year=2006 |title=ToxFAQs: CABS/Chemical Agent Briefing Sheet: Lead |url=http://www.atsdr.cdc.gov/cabs/lead/lead_cabs.pdf |archive-url=https://web.archive.org/web/20091009071912/http://www.atsdr.cdc.gov/cabs/lead/lead_cabs.pdf |archive-date=October 9, 2009 |url-status=dead }}</ref><ref name=Golub>{{cite book |isbn=978-0-415-70040-5 |chapter-url=https://books.google.com/books?id=Qt8LEB7_HyQC&pg=PA153 |page=153 |chapter=Summary |editor=Golub, Mari S. |year=2005 |publisher=Taylor and Francis |location=Boca Raton, Florida |title=Metals, fertility, and reproductive toxicity}}</ref><ref name=Hu>{{cite journal |last=Hu |first=Howard |title=Knowledge of diagnosis and reproductive history among survivors of childhood plumbism |journal=[[American Journal of Public Health]] |year=1991 |volume=81 |issue=8 |pages=1070–1072 |pmid=1854006 |doi=10.2105/AJPH.81.8.1070 |pmc=1405695}}</ref> and with [[Lead–crime hypothesis|increased levels of violence and criminality]] in America<ref>{{cite journal |last1=Mielke |first1=Howard W. |last2=Zahran |first2=Sammy |date=August 2012 |title=The urban rise and fall of air lead (Pb) and the latent surge and retreat of societal violence |url=https://www.sciencedirect.com/science/article/pii/S0160412012000566 |journal=Environment International |volume=43 |pages=48–55 |doi=10.1016/j.envint.2012.03.005 |pmid=22484219 |bibcode=2012EnInt..43...48M |access-date=April 22, 2022 |url-access=subscription }}</ref><ref name=NYT1>{{cite news |newspaper=[[The New York Times]] |date=February 7, 1996 |title=Aggressiveness and delinquency in boys is linked to lead in bones |url=https://www.nytimes.com/1996/02/07/us/aggressiveness-and-delinquency-in-boys-is-linked-to-lead-in-bones.html |archive-url=https://web.archive.org/web/20101125171319/https://www.nytimes.com/1996/02/07/us/aggressiveness-and-delinquency-in-boys-is-linked-to-lead-in-bones.html |archive-date=November 25, 2010 |url-access=limited |access-date=March 22, 2023 |last=Brody |first=Jane E. |author-link=Jane Brody}}{{cbignore}}</ref><ref name=NYT2>{{cite news |newspaper=[[The New York Times]] |date=October 21, 2007 |title=Clean Air Act: Criminal Element |last=Hoffman |first=Jascha |url=https://www.nytimes.com/2007/10/21/magazine/21wwln-idealab-t.html |archive-url=https://web.archive.org/web/20120919132926/http://www.nytimes.com:80/2007/10/21/magazine/21wwln-idealab-t.html?pagewanted=all |archive-date=September 19, 2012 |url-access=subscription}}{{cbignore}}</ref><ref name=MJ>{{cite magazine |magazine=[[Mother Jones (magazine)|Mother Jones]] |date=February 2013 |title=Lead: America's Real Criminal Element |last=Drum |first=Kevin |author-link=Kevin Drum |url=https://www.motherjones.com/environment/2013/01/lead-crime-link-gasoline}}</ref> and around the world.<ref>{{cite journal |last1=Nevin |first1=Rick |author1-link=Rick Nevin |date=July 2007 |title=Understanding international crime trends: The legacy of preschool lead exposure |url=https://www.sciencedirect.com/science/article/pii/S0013935107000503 |journal=Environmental Research |volume=104 |issue=3 |pages=315–336 |doi=10.1016/j.envres.2007.02.008 |pmid=17451672 |bibcode=2007ER....104..315N |access-date=April 22, 2022 |url-access=subscription }}</ref><ref>{{cite journal |last1=Taylor |first1=Mark Patrick |last2=Forbes |first2=Miriam K. |last3=Opeskin |first3=Brian |last4=Parr |first4=Nick |last5=Lanphear |first5=Bruce P. |date=February 16, 2016 |title=The relationship between atmospheric lead emissions and aggressive crime: an ecological study |journal=Environmental Health |volume=15 |issue=1 |page=23 |doi=10.1186/s12940-016-0122-3 |pmid=26884052 |pmc=4756504 |doi-access=free |bibcode=2016EnvHe..15...23T }}</ref> ''[[Time (magazine)|Time]]'' magazine included both leaded gasoline and CFCs on its list of "The 50 Worst Inventions".<ref>{{cite magazine|last1=Gentilviso|first1=Chris|title=The 50 Worst Inventions: Leaded Gasoline|url=https://content.time.com/time/specials/packages/article/0,28804,1991915_1991909_1991817,00.html|access-date=February 1, 2018|magazine=Time|date=May 27, 2010}}</ref>

Midgley died three decades before the [[Ozone depletion|ozone-depleting]] and [[greenhouse gas]] effects of [[Ozone depletion#CFCs and related compounds in the atmosphere|CFCs in the atmosphere]] became widely known.<ref name=Knight-2015>{{cite news |url=https://www.bbc.co.uk/news/magazine-33021668 |title=How 1970s deodorant is still doing harm |author=Laurence Knight |date=June 6, 2015 |work=BBC News |access-date=August 23, 2016}}</ref> In 1987, the [[Montreal Protocol]] phased out the use of [[chlorofluorocarbon|CFCs]] like Freon.<ref>[https://www.bbc.co.uk/news/science-environment-37665529 Climate change: 'Monumental' deal to cut HFCs, fastest growing greenhouse gases]</ref>

The harm of leaded gasoline and chlorofluorocarbons have been framed as lessons in known unknowns and [[unknown unknowns]], respectively. When leaded gasoline was invented it was known that lead had harmful effects on human health in large quantities, and that leaded gasoline caused emissions of trace amounts of lead to the atmosphere, but it was not known whether those trace amounts had adverse effects. The existence of the ozone layer, however, and the potential for chlorofluorocarbons to harm it, was not known at the time.<ref>{{Cite news |last=Johnson |first=Steven |date=March 15, 2023 |title=The Brilliant Inventor Who Made Two of History's Biggest Mistakes |url=https://www.nytimes.com/2023/03/15/magazine/cfcs-inventor.html |access-date=January 21, 2024 |work=The New York Times |language=en-US |issn=0362-4331|archive-url=https://web.archive.org/web/20240718071439/https://www.nytimes.com/2023/03/15/magazine/cfcs-inventor.html|archive-date=July 18, 2024}}</ref>

In 2022, Derek Muller, through his YouTube channel Veritasium, released a video titled ''"[https://www.youtube.com/watch?v=IV3dnLzthDA The Man Who Accidentally Killed the Most People in History]''<ref>{{Cite AV media |url=https://www.youtube.com/watch?v=IV3dnLzthDA |title=The Man Who Accidentally Killed The Most People In History |date=2022-04-22 |last=Veritasium |access-date=2025-11-06 |via=YouTube}}</ref>''"'', which had garnered over 40 million views by 2025.

In 2024, it was announced that screenwriter [[Terence Winter]] was co-writing a feature film about Midgley entitled ''Midge''.<ref name="IMDb">{{cite web |title=Midge |url=https://www.imdb.com/title/tt31322301/reference/ |website=IMDb.com |publisher=IMDb.com, Inc. |access-date=May 27, 2024}}</ref><ref>{{cite web |last1=Grobar |first1=Matt |title=Terence Winter Teaming With Vincent Piazza, Appian Way & Phiphen To Develop Tragicomedy 'Midge' On Toxic Chemical Inventor Thomas Midgley, Jr. |url=https://deadline.com/2024/02/terence-winter-appian-way-developing-midge-1235826752/ |website=Deadline |date=February 15, 2024}}</ref>

==References==
{{reflist}}

==Further reading==
* {{cite web |title=Cautionary Tales{{ndash}}The inventor who almost ended the world |date=November 11, 2022 |author=Tim Harford |format=Podcast |url=https://timharford.com/2022/11/cautionary-tales-the-inventor-who-almost-ended-the-world/}}
* [https://web.archive.org/web/20230315182035/https://www.nytimes.com/2023/03/15/magazine/cfcs-inventor.html?campaign_id=61&emc=edit_ts_20230315&instance_id=87762&nl=the-great-read&regi_id=58413496&segment_id=127851&te=1&user_id=80cf60cec3adc1d45fcb7c0a94e1fe11 The Brilliant Inventor Who Made Two of History’s Biggest Mistakes]. Stephen Johnson, [[New York Times Magazine]],  March 15, 2023.
* Midgley{{ndash}}Man of Marvels, [https://chroniclingamerica.loc.gov/lccn/sn88063294/1945-03-25/ed-1/seq-72/  (page 1 of 2)],  [https://chroniclingamerica.loc.gov/lccn/sn88063294/1945-03-25/ed-1/seq-73/ (page 2 of 2)]. [[Charles F. Kettering]], [[The American Weekly]], [[Hearst Corporation]], March 25, 1945.

==External links==
* {{cite journal |pmid=17833986 |last=Midgley |first=T. |year=1942 |title=A Critical Examination of Some Concepts in Rubber Chemistry |volume=96 |issue=2485 |pages=143–6 |doi=10.1126/science.96.2485.143 |journal=[[Science (journal)|Science]]|bibcode=1942Sci....96..143M }}
* {{webarchive |url=https://web.archive.org/web/20121015120545/http://books.nap.edu/html/biomems/tmidgley.pdf |archive-url=https://web.archive.org/web/20081030183309/http://books.nap.edu/html/biomems/tmidgley.pdf |archive-date=October 30, 2008 |url-status=live |date=October 15, 2012 |title=Biographical Memoir by Charles F. Kettering }}
* {{cite journal|url = http://www.scs.illinois.edu/~mainzv/HIST/bulletin_open_access/v31-2/v31-2%20p66-74.pdf|first = Carmen J.|last = Giunta|title = Thomas Midgley Jr. and the Invention of Chlorofluorocarbon Refrigerants|journal = [[Bulletin for the History of Chemistry]]|volume = 31|issue = 2|year = 2006|pages = 66–74| doi=10.70359/bhc2006v031p066 |access-date = June 12, 2012|archive-date = April 23, 2016|archive-url = https://web.archive.org/web/20160423012402/http://www.scs.illinois.edu/~mainzv/HIST/bulletin_open_access/v31-2/v31-2%20p66-74.pdf|url-status = dead}}
* [https://www.youtube.com/watch?v=IV3dnLzthDA The Man Who Accidentally Killed The Most People In History] (video by YouTube producer [[Derek Muller]] on Thomas Midgley Jr., April 2022)

{{Presidents of the American Chemical Society}}
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{{DEFAULTSORT:Midgley, Thomas Jr.}}
[[Category:1889 births]]
[[Category:1944 deaths]]
[[Category:20th-century American chemists]]
[[Category:20th-century American engineers]]
[[Category:20th-century American inventors]]
[[Category:Accidental deaths in Ohio]]
[[Category:Air pollution]]
[[Category:Cornell University College of Engineering alumni]]
[[Category:Deaths by strangulation in the United States]]
[[Category:Environmental controversies]]
[[Category:Human impact on the environment]]
[[Category:Inventors killed by their own invention]]
[[Category:Lead poisoning incidents]]
[[Category:Mass poisoning]]
[[Category:Members of the United States National Academy of Sciences]]
[[Category:Ozone depletion]]
[[Category:People from Beaver Falls, Pennsylvania]]
[[Category:Polio survivors]]