Three Inventions and a Funeral
Today is Thomas Midgley Day — definitely not the Saviour of the Human Race
Today is Tom Midgley Day, celebrating the 133rd anniversary of the birth of Thomas Midgley Jnr, the American engineer and chemist, on 18th May 1889.
Who Tom Midgley you ask? He is the man who, despite always having the best intentions, unwittingly unleashed two major health hazards on an unsuspecting world. J. R. McNeill, the environmental historian, said that Midgley “had more impact on the atmosphere than any other single organism in Earth’s history,” while Bill Bryson has commented that Midgley possessed “an instinct for the regrettable that was almost uncanny.”
It all began in 1921, when he discovered that adding lead — technically tetraethyllead (or TEL) — to gasoline (or petrol) was a cheap way of preventing knocking in internal combustion engines. The substance was called Ethyl and all mention of lead in reports and advertising was avoided.
By 1924 at least 15 employees working at TEL processing plants in the US had died from lead poisoning and many others were reporting symptoms ranging from depression and hallucinations to insanity. Midgley himself suffered severe lead poisoning and had to take a long vacation in Florida, reporting it “necessary to drop all work and get a large supply of fresh air”.
However this did not stop him from participating in a press conference in October 1924 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 60 seconds, declaring that he could do this every day without succumbing to any problems. By April 1925 his ill health — caused by the lead poisoning — meant he had to leave his job as vice-president of the company making Ethyl.
Undaunted by his experiences with TEL, in the late 1920s Midgley, now working for the Frigidaire division of General Motors, began looking for a non-toxic, non-flammable alternative to these refrigerants used in air conditioning and refrigeration systems. At the time the industry employed compounds such as ammonia (NH3), chloromethane (CH3Cl), propane, and sulfur dioxide (SO2) as refrigerants, which although effective, were also toxic, flammable or explosive.
The Frigidaire team soon narrowed their focus to alkyl halides (the combination of carbon chains and halogens), which were known to be highly volatile (a requirement for a refrigerant) and also chemically inert. They eventually settled on the concept of 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 breakdown products.
The team eventually synthesized dichlorodifluoromethane, the first chlorofluorocarbon (CFC), which they named Freon. Freon and other CFCs soon replaced the other refrigerants, and later appeared in other applications, such as propellants in aerosol spray cans and asthma inhalers.
Having contributed lead pollution and ozone depletion to the atmosphere, in 1940 Midgley contracted polio and was left disabled. He therefore devised his third and final invention: a system of ropes and pulleys to help others lift him from his bed. Unfortunately, in early November 1944, he became entangled in his own contraption’s ropes and died of strangulation.
