Once hailed as a genius, Thomas Midgley Jr is now seen as history’s most accidentally dangerous man, whose inventions – from leaded petrol to CFCs – killed millions
Thomas Midgley Jr was once renowned as a trailblazing innovator, one of America’s foremost minds. But now, almost a century after his grisly death, he is considered one of history’s worst inventors, “a one-man environmental disaster” and the human who has inadvertently killed more people in history than any other – including himself.
Midgley was born to invent. A native of Beaver Falls, Pennsylvania, a riverside town renowned for cutlery manufacturing, his father had been a pioneer in the automobile tire industry. Midgley’s maternal grandfather had been the inventor of the inserted tooth saw.
Growing up, he was a bookish and industrious boy. His friends remember him using chewed up tree bark from elm trees to lubricate his baseball bats and give his swings a curved trajectory, a technique later adopted by professional players.
He would also carry in his pocket a print copy of the periodic table wherever he went, his key to understanding the world around him at the most molecular level. In 1911, at the age of 22, he would graduate from Cornell University with a degree in mechanical engineering, the Ivy League alma mater of 64 Nobel Laureates and 63 medal-winning Olympians.
Historian Gerald Markowitz said of the period: “It was the dawn of the automobile era in the United States”. Competing companies were trying to edge one another out to build the most powerful automobile engines, and in 1916, Midgley entered the rat race on the side of General Motors, then under the aegis of another inventor, Ohio’s Charles Kettering.
The main problem faced by motor companies was “engine knocking”, tiny explosions caused in car engines by low quality gasoline. Under both pressure and guidance from Kettering, Midgley went through thousands of chemical substances, many extremely toxic, to find a way to stabilise gasoline. Eventually, he settled on tetraethyl lead, a lead derivative sold on the markets under the mononym Ethyl.
Lead, even in extremely low concentrations, is highly poisonous. It has been heavily linked to developmental and cognitive impairment, and large doses can induce symptoms such as anaemia, seizures, comas and death. According to the World Health Organisation, 1.5 million people were killed by lead exposure in 2021 alone.
When Ethyl first went on sale in 1921, the metal’s adverse effects were already well known. As early as the 2nd century BC, the Greek botanist Nicander had described the toxic symptoms of lead poisoning. Benjamin Franklin wrote of the dangers of lead in the 1780s. Household lead paint was banned in some countries from as early as 1897 thanks to pressure from campaigners, warning it was killing kids.
But General Motors and Midgley insisted that lead, when ejected from the exhaust pipe of a car, had no inherent dangers. Midgley was so confident of this fact that, in 1924, he poured Ethyl over his hands and inhaled it before a crowd of curious journalists. “I could do this every day,” Midgley proudly declared, “without getting any health problems whatsoever.”
By this point, serious red flags were already being raised about the invention, hence Midgley’s press conference theatrics. Engines were running smoother, but in October 1924 six General Motor employees had died and tens of others were hospitalised when lead exposure sent them into a mania at the workplace, first inducing a mindless fury then paralysing them on the ground in crazed laughter. Those who survived had to be wrestled into straightjackets.
Despite these known dangers, the automobile industry lobbied for leaded gasoline to remain on the markets, only phasing it out in 1996. By that point, millions of Americans had been exposed to irreversibly dangerous levels of lead in early childhood, with a 2022 study estimating that as much as half of America’s population could be suffering the adverse effects. In 2021, Algeria finally became the last country in the world to ban Midgley’s invention.
Yet somehow, this leaded gasoline wasn’t Midgley’s most dangerous invention. In the years after his leaded gasoline “success”, he synthesised Freon, a non-toxic and non-flammable compound that could be safely used for air conditioning and refrigeration systems, as well as household aerosols like hairspray. It was the first CFC, a compound that would soon be everywhere.
At the time, the invention was lauded: Midgley won awards and medals, including the prestigious Priestly Medal. In 1944, he was elected president and chairman of the American Chemical Society, the chemical engineering industry’s highest honour.
But four decades later, the Montreal Protocol was signed, an international treaty eliminating CFCs. It had been discovered that CFC emissions had poked a hole in the ozone layer above the Antarctic, allowing ultra-dangerous, cancer-causing ultraviolet radiation to pour through our atmosphere. If CFCs dangers hadn’t been discovered, the ozone puncture could have become so large that the consequences would be apocalypse, the complete destruction of all life on Earth.
Midgley didn’t live to see his own disgrace. After contracting polio in 1940, Midgley was left severely disabled and totally bed-bound. His solution was another invention: a system of ropes and pulleys that would lift him out of bed every morning.
But on the morning of November 2nd, 1944, he was found dead in his home, strangled by his own device. Although it initially seemed a tragic accident, coroners ruled his death suicide. Allegedly, he had killed himself in a rabid psychosis, a mental state induced by his own lifetime of exposure to highly-toxic lead.
