While working for General Motors in 1921, Tomas Midgley Jr (then 32) discovered that adding tetra-ethyl lead to gasoline would stop “engine knock”, and leaded gasoline was born. On February 1, 1923, Dupont, Standard Oil and GM started selling tetra-ethyl lead (TEL) through a Corporation called the Ethyl Gasoline Corporation. It still exists today under the name “Ethyl Corporation“.
Of course lead is highly toxic and working with it is very dangerous. Ethyl Gasoline Corporation employees suffered a rash of deaths and dementia which the company, and Midgley himself (in spite of having a lead poisoning incident of his own), tried their darnedest to cover up. Thanks to the atmospheric lead produced by burning Midgley’s leaded gasoline, you and I have 625 times more lead in our blood than people before 1923.
In 1930 Midgley then turned is unique talents to finding a safer gas that could be used in cooling systems such as refrigerators. What he came up with was Chlorofluorocarbons (CFCs) which were promptly added to everything from hairspray to air conditioners. We now know that a single kilogram of CFC’s can destroy 70,000 kilograms of ozone.
In 1940 Tomas Midgley was stricken with polio and, bedridden, invented a system of ropes and pulleys to help him move around. In a karmic twist Midgley became entangled in the ropes and was found strangled to death in 1944, long before he could learn that his second invention was doing to the world what his third invention did to him.
 Bryson, Bill. A Short History of Nearly Everything. (2003) Broadway Books, USA. ISBN 0385660049