About ozone-depleting substances

Some substances damage the Earth’s ozone layer and the international community is working towards phasing them out. Find out more about these substances and New Zealand’s role.

During the 1970s, scientists discovered that if certain chemicals are released into the atmosphere, they can damage and thin the Earth’s ozone layer. This layer in our atmosphere protects all life on Earth as it absorbs harmful type of ultra-violet light called UVB, which causes sunburn, skin cancer and cataracts. Many ozone-depleting substances are also potent greenhouse gases, and contribute to climate change.

As a result, every member country in the United Nations ratified the Montreal Protocol, an international agreement to phase out the substances responsible. This agreement was the first universally-ratified treaty in the history of the United Nations.

This combined international effort means the ozone layer is slowly recovering.

Ozone-depleting substances restricted under the Montreal Protocol

For a complete list of the names of individual ozone-depleting controlled substances and their chemical formulae, see schedule 1 of the Ozone Layer Protection Regulations 1996

Substance/group of substances	Other names (not exhaustive)	Uses
Chlorofluorocarbons, other fully halogenated chlorofluorocarbons	CFCs	Aerosol propellant, refrigeration and air-conditioning systems, in foams, in cleaning solvents and electrical components.
Halons	Bromotrifluoromethane, Halon 1301, bromochlorodifluoromethane, Halon 1211	Fire suppressants in fire extinguishers, specialist fire extinguishers, and propellants in pesticide sprays.
Carbon tetrachloride	Tetrachloromethane, carbon tet, Halon-104, Refrigerant-10	Aerosol propellant, refrigerant, dry-cleaning agent, degreasing agent, in fire extinguishers, as a pesticide and as a sheep medicine.
Methyl chloroform	1,1,1-TCA, methyl chloroform, chlorothene, Solvent-111, R-140a	Was widely-used as solvent and degreasing agent. Still used in industry and occasionally in domestic spot cleaners, glues and aerosol sprays.
Hydrobromofluorocarbons	HBFCs	Solvents, cleaning agents, fire suppressants, refrigerants.
Hydrochlorofluorocarbons	HCFCs	Replacement for CFCs after they were phased out as a refrigerant, used in production of insulating foams and as solvents.
Methyl bromide	Bromomethane, mono-bromomethane, and methyl fume	Natural and man-made sources. Fumigation of shipments during quarantine and before shipment. Was used to produce other chemicals for industrial production of pharmaceuticals, other pesticides, refrigerants, solvents and cleaning agents, fire extinguishing agents, and nut and seed oil extraction.
Bromochloromethane	Methylene bromochloride and Halon-1011, borothene, chloromethyl bromide, methyl chlorobromide, monochloromonobromomethane chlorobromomethane, fluorocarbon-1011)	Fire extinguishing fluid, explosion suppressant, solvent, and used in the production of some insecticides.

To read about the rules for hydrofluorocarbons (HFCs), which were developed to replace some of these ozone-depleting substances, see our web page:

Importing and exporting hydrofluorocarbon gases (HFCs)

Ozone-depletion potential

When these substances reach the upper atmosphere, they create chemical reactions which cause the ozone molecules in the atmosphere to break down. Different substances break down ozone more rapidly than others. This is measured by their ozone-depletion potential (ODP).

Graph showing the relative ozone-depletion potential of controlled gases

Graph showing the ozone-depletion potential (ODP, or potential damage that each substance could cause to the ozone layer), relative to the chlorofluorocarbon, CFC-11.

New Zealand’s role in phasing out ozone-depleting substances

The international community agreed (under the Vienna Convention, and the Montreal Protocol and subsequent amendments to this agreement) to a schedule for phasing out newly-manufactured quantities of ozone-depleting substances, and targets for reducing the net consumption of existing substances to zero.

In New Zealand, this is achieved (under the Ozone Layer Protection Regulations 1996) by:

prohibiting the import and manufacture of new substances (most of these substances are man-made) and those contained in manufactured products
restricting imports to recycled substances, in bulk, and
reducing the annual quantity over time of recycled substances that can be imported into the country.

Download the timeline showing the international agreements on ozone depleting substances (pdf 115KB)

New Zealand’s consumption of ozone-depleting substances

New Zealand has met international requirements for phasing out ozone-depleting substances. Phasing out these substances means that we ensure that any net imports of new bulk substances is matched by an export of an equivalent amount.

At the present, the vast majority of applications to import ozone-depleting gases into New Zealand include:

import exemptions granted for aircraft entering New Zealand with fire extinguishers containing halons. Aircraft must have these fire extinguishers under international aviation requirements
import permits for methyl bromide for quarantine or pre-shipment fumigation (QPS).

Applications to import other types of ozone-depleting substances are rare (1 to 2 per year in recent years).

These graphs show the reducing trends of consumption of ozone-depleting substances in New Zealand (net imports of new bulk imports minus exports). Note that the use of methyl bromide for quarantine or pre-shipment fumigation (QPS) is legitimate under international agreements.