An image showing CFC molecules. C is carbon, Cl is chlorine and F is fluorine.

NASA projection of stratospheric ozone, in Dobson units, if chlorofluorocarbons had not been banned.

A chlorofluorocarbon (CFC) is a gas used for various purposes including solvents, refrigerants, and aerosol sprays. They are organic chemicals and contain carbon, hydrogen, chlorine, and fluorine. They were much used in the middle of the 20th century, replacing chemicals that were toxic or flammable or had other problems.