Ozone depleting substances

Ozone depleting substances

Klaxon air horn F12 freon (image taken as part of the Ozone Protection and Synthetic Greenhouse Gas [OPSGG] program)

For key facts and information at a glance, please read our ozone depleting substances factsheet.

What are ozone depleting substances?

Ozone depleting substances are chemicals that destroy the earth’s protective ozone layer. They include:

  • chlorofluorocarbons (CFCs)
  • halon
  • carbon tetrachloride (CCl4)
  • methyl chloroform (CH3CCl3)
  • hydrobromofluorocarbons (HBFCs)
  • hydrochlorofluorocarbons (HCFCs)
  • methyl bromide (CH3Br)
  • bromochloromethane (CH2BrCl)

Production and import of these chemicals is controlled by the Montreal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol). There are other ozone depleting substances, but their ozone depleting effects are very small, so they are not controlled by the Montreal Protocol.

Did you know: One kilogram of halon 1211 can destroy 50 tonnes of ozone

What is ozone depleting potential?

Ozone depleting potential is a measure of how much damage a chemical can cause to the ozone layer compared with a similar mass of trichlorofluoromethane (CFC-11). CFC-11, with an ozone depleting potential of 1.0, is used as the base figure for measuring ozone depleting potential. The higher the number, the more damage a chemical can cause to the ozone layer. Bromotrifluoromethane (halon‑1301) has an ozone depleting potential of 10.0. Carbon dioxide (CO2), a naturally occurring greenhouse gas, has an ozone depleting potential of 0.

What did we use ozone depleting substances for?

The main uses of ozone depleting substances include:

  • CFCs and HCFCs in refrigerators and air conditioners,
  • HCFCs and halons in fire extinguishers,
  • CFCs and HCFCs in foam,
  • CFCs and HCFCs as aerosol propellants, and
  • methyl bromide for fumigation of soil, structures and goods to be imported or exported.

Progress in phasing out ozone depleting substances

Production of most ozone depleting substances has been phased out under the Montreal Protocol. In Australia and other developed countries the phase out of the most potent chemicals happened between 1991 and 1995. Australia's import of HCFCs, which have lower ozone depleting potential, dropped from 250 ODPt (ozone depleting potential tonnes) in 1996 to 2.5 ODPt in 2016.

The Ozone Protection and Synthetic Greenhouse Gas Management Act 1989 controls the manufacture, import export, use and disposal of ozone depleting substances in Australia. Bulk import into Australia of most of these substances (except HCFCs and methyl bromide) is banned.

This report provides an overview of Australia’s progress towards meeting its commitments under the Montreal Protocol and compares Australia’s production and import of key ozone depleting substances to other groups of countries.

Why do we still use some ozone depleting substances?

Some ozone depleting substances with a high ozone depleting potential are still used in quarantine and safety applications as no suitable alternative exists. Methyl bromide is extremely effective as a quarantine fumigant. The immediate fire suppression qualities of halon are needed in confined spaces such as on airplanes and in submarines. Research is continuing to find suitable replacements.

Alternatives to ozone depleting substances

USA SNAP (Significant New Alternatives Policy)

The USA EPA (Significant New Alternatives Policy) program provides information on alternatives to ozone depleting substances.

Further information