The chloroflurocarbons (CFCs) are a family of organic carbons containing carbon, hydrogen and either chlorine or fluorine, or both. CFCs have a number of commercial applications such as refrigerators, cleaning fluids, propellants etc. Scientists have found that CFCs in the stratosphere decompose by sunlight. One product of decomposition, atomic chlorine reacts with ozone (O3) to form oxygen. This reaction poses a threat to the ozone layer.