Have you ever heard the story about the inventor who created two things that should have been revolutionary, but instead became a global disaster? Thomas Midgley Jr. is the person.

So in 1924, Midgley poured leaded gasoline directly into his hand and inhaled it in public to prove it was safe. The idea was simple—tetraethyl lead could solve the engine knocking problem that was a major issue at the time. People were amazed, considered it a huge breakthrough. But it turned out to be extremely toxic. Millions of people worldwide were poisoned by lead, especially children whose development was severely affected.

Even crazier, after Midgley contracted polio and became paralyzed, he actually invented Freon—the CFC refrigerant considered super safe and non-flammable. This was also seen as revolutionary at the time. Freon immediately boomed in the cooling and air conditioning industry everywhere. But in the 1970s, scientists discovered that Freon and other CFCs severely damaged the ozone layer. As a result, harmful ultraviolet radiation started entering Earth in greater amounts.

Eventually, leaded gasoline was banned in the United States in 1996—though many other countries continued using it much longer. Then came the Montreal Protocol in 1987, which aimed for the global elimination of CFCs. Now the ozone layer is beginning to recover, but the damage already done still impacts millions of people and ecosystems around the world.

What’s most tragic? Midgley's life ended in a very strange way. In 1944, he got entangled and choked in a pulley system he himself designed to help him get out of bed. So this story serves as a strong reminder—innovation carries great responsibility, and unintended consequences can come from the things we think are safest.