CFCs

• Chlorofluorocarbons, also known as CFCs, are widely held to be the primary cause of ozone layer depletion. A CFC is an organic compound containing carbon, chlorine and fluorine. It is produced as an volatile derivative of methane and ethane. The discovery of CFCs as being the main cause of ozone depletion was made by Drs. Mario "MJ" Molina and F. Sherwood Rowland in 1974. Their discovery wasn't accepted, however, until the first hole in the ozone layer was discovered in 1985 over Antarctica.
  
  

HCFCs

• Hydrochlorofluorocarbon, otherwise known as HCFCs, are a class of chemicals developed to use in place of CFCs. Because HCFCs contain chlorine, they deplete the stratospheric section of the ozone. However, they do so to a lesser extent than more-harmful CFCs. According to the U.S. Environmental Protection Agency, HCFCs with a higher level of ozone depletion are being phased out, with less-damaging HCFCs set to slowly replace them.
  
  

Methyl Bromide

• Methyl bromide is another chemical that affects the ozone layer and increases depletion. Methyl bromide is an colorless, odorless gas that is used as a soil fumigant and structural fumigant meant to control pests across a wide range of agricultural sectors. Because methyl bromide depletes the stratospheric ozone layer, the amount produced and imported in the United States was reduced incrementally. It was eventually phased out in 2005, pursuant to the Montreal Protocol on Substances that Deplete the Ozone Layer (Protocol) and the Clean Air Act (CAA).
  
  

Halons

• Halons are another pollutant that negatively impacts the Earth's ozone layer. A halon is a compound that consists of bromine, fluorine and carbon. They are used in both in built-in fire extinguisher systems and in hand-held fire extinguishers. Bromine is the primary ingredient of halons that cause ozone depletion. Because of the compound's affect on ozone depletion, the United States stopped producing halons in 1993.