He held more than 100 patents, won the most prestigious awards in his field, and died convinced he was a savior of humanity. Decades later, historians began calling him the single most destructive organism in the history of the planet. This episode is a deep dive into Thomas Midgley Jr., the GM engineer whose two flagship inventions accidentally rewired the atmosphere.

We trace the two miracles. First, tetraethyl lead, the anti-knock agent that solved the engine knocking problem and ushered in the era of leaded gasoline, despite a string of suspicious deaths at the Standard Oil Bayway plant and his own bouts of lead poisoning that he kept treating as PR problems. Then, after he was quietly removed as vice president of GM Chemical, his even more consequential second act: chlorofluorocarbons, marketed as Freon, which solved the safety  ...