Chlorofluorocarbons were discovered around 1930 by Thomas Midgley. They are nontoxic, nonflammable chemicals containing carbon, chlorine, and fluorine. There are four basic uses for chlorofluorocarbons (CFCs); refrigerants, foam blowing agents, cleaning agents, and propellants. As refrigerants, CFCs are used in refrigerators, freezers, and in air conditioning units in homes and automobiles. CFCs as blowing agents are used in making both rigid foam, used in ice chests or fast food boxes, or as flexible foam, used in furniture cushions and foam pillows. Hundreds of products from computer chips to artificial hip joints are cleaned with chlorofluorocarbons. Another use for chlorofluorocarbons is in fire extinguishers and urethane shoe soles.
             In the 1920s there were a series of fatal accidents due to the very toxic methyl chloride. A search for a less toxic alternative began and CFCs were discovered. The first patent was issued for CFCs by Frigidaire and millions of new refrigerators were sold. Because CFCs had a record of nontoxicity, it not only became the preferred coolant but the only one allowed. It was an inexpensive solution to the desire for air conditioning in many cars, homes, and office buildings. In the 1950s and 1960s the annual sales of CFCs was about a billion dollars, producing more than one million metric tons.
             CFCs are safe to use in most applications and are inert in the lower atmosphere, but in the upper atmosphere or stratosphere they undergo significant reactions. In 1974 it was shown that CFCs could possibly be a major contributor of inorganic chlorine in the stratosphere due to their photolytic decomposition by UV radiation. Also, some of the released chlorine was actively destroying ozone in the stratosphere. Ozone absorbs ultraviolet radiation which can cause biological damage in plants and animals, and a loss of stratospheric ozone results in more UV radiation reaching the Earth&apos
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