Fluorides are chemical compounds that contain fluorine, when treated with sulfuric acid, fluorides produce hydrogen fluoride. This is a chemical used in aluminum production. In addition, hydrogen fluoride is used to produce compounds known as chlorofluorocarbons, or CFCs. CFC compounds are widely used as refrigerants for air conditioners and refrigerators. They are also uses to make insulation foams for furniture and buildings. There is a downside, however, to producing CFCs. When released into the air, CFC molecules rise into the ozone layer of the earth is upper atmosphere. Ozone is a form of oxygen that protects life on earth from the sun is harmful ultraviolet rays. As CFCs travel higher in the atmosphere, the ultraviolet rays cause chlorine atoms then react with ozone to create ordinary oxygen. Thus, the overuse of products releasing CFCs may over time create holes in the earth is ozone layer.