Thomas Midgley Jr. His Inventions Poisoned the Whole Planet

A cheerful problem-solver

Thomas Midgley Jr. was born in Beaver Falls, Pennsylvania, in 1889. By all accounts he was a brilliant and cheerful engineer who loved a hard problem. In 1916 he joined the inventor Charles Kettering in Dayton, Ohio.

The knock

Car engines of the time had a serious problem: knocking, a violent rattle that wasted fuel and damaged engines. Midgley spent years testing compound after compound to add to petrol. In December 1921 he found one that worked: tetraethyl lead.

Engines ran smoothly and powerfully. There was just one problem: lead is a poison. The product was marketed as "Ethyl", without the word lead.

Looney gas

In 1923 and 1924 workers at the plants that made tetraethyl lead, in Dayton, at DuPont's works in Deepwater, New Jersey, and at Standard Oil's plant in Bayway, began to suffer hallucinations and violent fits. At least fifteen of them died. Newspapers called the stuff "looney gas".

Midgley responded with a press conference in October 1924. He poured tetraethyl lead over his hands and breathed its fumes for about a minute, and told reporters he could do so every day without harm. He did not mention that not long before, he himself had needed treatment for lead poisoning.

Leaded petrol went around the world. For decades, hundreds of millions of cars blew lead into the air.

Freon

Midgley then turned to refrigerators, which at the time used toxic or flammable gases that could leak and kill people. In 1928 his team created a new gas that seemed perfectly safe: a chlorofluorocarbon, sold as Freon. To show how harmless it was, he inhaled it at a demonstration and blew out a candle.

CFCs were soon everywhere: in refrigerators, air conditioners and spray cans. Midgley received the highest honours in American chemistry.

The ropes

In 1940, at 51, Midgley caught polio and was left with paralysed legs. True to form, he designed a system of ropes and pulleys to help himself out of bed. In November 1944 he was found entangled in those ropes and died, at 55. His death is often told as "killed by his own invention", but the official record and historians disagree on whether it was an accident or suicide.

What he never saw

Decades after his death, scientists found that people carried far more lead in their bodies than their ancestors had, with harm to children's health and development. And in the 1970s and 1980s scientists showed that CFCs were destroying the ozone layer, which protects life from ultraviolet radiation.

Country after country banned both. The 1987 Montreal Protocol phased out CFCs, and the last leaded petrol for cars was sold in 2021.

The historian J. R. McNeill wrote that Midgley "had more impact on the atmosphere than any other single organism in Earth's history". That is one historian's judgement, not a measurement, but it is hard to argue with. Midgley solved every problem in front of him. He never asked what would happen next.