I 1921 udviklede [[Thomas Midgley Jr.]], der var ansat ingeniør hos GM, [[tetraetylbly]] (blyholdig benzin) som et middel mod motorbanken. GM fik [[patent]] på opfindelsen,<ref>{{cite web |title=Thomas Midgley, Jr. {{!}} American chemical engineer |url= https://www.britannica.com/biography/Thomas-Midgley-Jr |access-date=13. maj 2023 |website=britannica.com |language=en}}</ref> der muliggjorde udvikling af kraftigere og mere effektive motorer. GM's ledelse var bekendt med de helbredsrisici, som tetraetylbly påfører miljøet og mennesker.<ref name="Kitman">{{cite magazine |last=Kitman |first=Jamie |url= http://www.thenation.com/article/secret-history-lead?page=full | title=The Secret History of Lead | archive-url=https://web.archive.org/web/20140510105351/http://www.thenation.com/article/secret-history-lead?page=full |archive-date=10. maj 2014 |magazine=The Nation | date=2. marts 2000}}</ref><ref>{{cite magazine |last=Eschner |first=Kat |title=Leaded Gas Was a Known Poison the Day It Was Invented |url= https://www.smithsonianmag.com/smart-news/leaded-gas-poison-invented-180961368/ |magazine=Smithsonian | date= 9. december 2016}}</ref>
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