They were invented in the 1920s by Thomas Midgley, Jr.
CFCs are also known as Freon – its commercial name marketed by DuPont
Initially perceived as a cheap, safe chemical (low toxicity, low reactivity and
low flammability at the troposphere), CFCs were used as refrigerants,
propellants, solvents and blowing agents
However, it was later suggested by chemists Sherwood Rowland and Mario
Molina in 1974 that CFCs were lowering the concentration of ozone in the
stratosphere