“Workers suffered bouts of violent paranoia and were hauled away in straitjackets” Corbis via Getty Images

BY THE time of his death in 1944, Thomas Midgley Jr was regarded as one of the great inventors of the 20th century. From cars to kitchens, his creations ran the gamut. He had turned Henry Ford’s “bangers” into speedy, must-have Cadillacs with a magic ingredient added to petrol, and for an encore found a chemical that made killer refrigerators and aircon units safe for millions of homes.

On the face of it, an enviable legacy – except that the products of Midgley’s genius were fatally flawed. His lead-based petrol additive damaged the developing brains of millions of children globally; and Freon, the first CFC, almost destroyed Earth’s ozone layer. Midgley is now seen as the world’s worst inventor.

Born in 1889, Midgley’s first claimed invention – made in high school – was a method for curving the flight of baseballs, by rubbing them with the chewed bark of the slippery elm. It was widely used thereafter by baseball pitchers. Later, after a stint working for his father’s tyre development company, Midgley came under the wing of Charles Kettering, the inventor of the electric starter motor for cars. In 1916, Kettering set 27-year-old Midgley to work on a solution to the problem of car engine “knock”.

Caused by the badly timed ignition of fuel, knock was noisy, jolting and effectively prevented the use of more efficient higher-octane fuel. It probably led to early automobiles being dubbed “old bangers”. Midgley came up with no fewer than 143 fuel additives to deal with knock. The initial front runner …