Leaded gasoline prevented engine ping, making driving safer and more pleasant. Correspondingly, it also caused an enormous amount of extremely toxic pollution.
Working for GM under the direct supervision of Charles Kettering at Dayton Research Laboratory, Midgley discovered the benefits of adding lead to gasoline. They named their innovation Tetraethyllead, avoiding any mention of lead, a known toxin.
Eventually, Tetraethyllead leaded gasoline became the standard, with tailpipes emitting poison throughout the world.
Eventually, the catalytic converter enabled lead-free gasoline. Virtually all countries banned Midgley’s leaded gasoline by the mid-1990s and early 2000s.
Speculation remains that the lead pollution had profound health and environmental impact. A substantive decline in violent crime is sometimes attributed to the banning of Midgley’s Tetraethyllead.
Midgley’s lead plant both killed many people and drove others insane.
Midgley also invented CFC’s putting him in the running for the most destructive scientist of all time, short-listed with the likes of Fritz Haber.
Eventually, Midgley died from a pully contraption he invented.