Midgley was tasked with finding a safe and non-toxic refrigerant to replace hazardous substances like ammonia, methyl chloride, and sulfur dioxide, which were commonly used in refrigerators at the time.

Midgley and his team successfully synthesized dichlorodifluoromethane (CFC-12), the first Freon refrigerant. It was marketed as a safe, stable, and non-flammable alternative to existing refrigerants.

Freon refrigerants quickly gained popularity and were widely adopted in refrigerators, air conditioners, and other cooling applications. Production and use of CFCs expanded rapidly worldwide.

It was later discovered that CFCs contribute to ozone depletion in the Earth's atmosphere, leading to the Montreal Protocol in 1987, which phased out the production and use of CFCs. This highlighted the long-term environmental consequences of Midgley's invention.