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Methyl bromide

Methyl bromide kills all pests, from microbes to insects and weeds. It is also extremely toxic to humans. It is used mainly to fumigate soil (often for crops such as strawberries and tomatoes). It is also used to fumigate imported goods being held in quarantine, and some export products, such as logs and fruit.

It is a significant ozone depleting substance and its use is controlled under the Ozone Layer Protection Regulations. Importing of methyl bromide for non-quarantine and pre-shipment use is being phased out by 2005.

There are only two companies in New Zealand which import methyl bromide. Entitlement to import methyl bromide for general use was allocated to these two wholesalers on the basis of their market share in 1993. Import permits are issued annually and are subject to reductions as set out in the Ozone Layer Protection Amendment Regulations 1997.

Definition of quarantine and pre-shipment

The use of methyl bromide for quarantine and pre-shipment is governed by the following definitions:

“Quarantine applications”, with respect to methyl bromide, are treatments to prevent the introduction, establishment and/or spread of quarantine pests (including diseases), or to ensure their official control, where:

  1. Official control is that performed by, or authorised by, a national plant, animal or environmental protection or health authority.
  2. Quarantine pests are pests of potential importance to the areas endangered thereby and not yet present there, or present but not widely distributed and being officially controlled.

“Pre-shipment applications” means any treatments other than quarantine applications applied no less than 21 days prior to export to meet the official requirements of the importing country or existing official requirements of the exporting country, where official requirements are those which are performed, or authorised, by a national plant, animal, environmental, health or stored product authority.

In brief, treatments required by a Government agency as part of an official control programme are considered to be Quarantine or Pre-shipment (QPS). Methyl bromide used voluntarily for quality control reasons (for example, to eradicate cockroaches) is not QPS.

In applying these definitions, Parties to the Protocol have been asked to refrain from use of methyl bromide and to use non-ozone-depleting technologies wherever possible. Where methyl bromide is used, Parties are urged to minimise emissions and use of methyl bromide through containment and recovery and recycling methodologies to the extent possible.

Critical uses of methyl bromide

After the final phase-out of methyl bromide for uses other than QPS in 2005, Parties to the Montreal Protocol may continue to import methyl bromide for “critical uses”. This term is an equivalent idea to the existing “essential use exemptions” already allowed after phase-out for other substances such as CFCs (an example of such an “essential use” exemption are the CFCs used in asthma inhalers.)

Growth in the use of methyl bromide for quarantine and pre-shipment

The use of methyl bromide for quarantine and pre-shipment purposes has climbed steeply in many countries over recent years. This reflects an increase in international trade, and an increased awareness of the need for effective biosecurity measures. New Zealand is among the countries whose use of methyl bromide has risen (we are, for example, exporting more timber to countries which require fumigation at the port of export).

The increase in use has led to debate among Parties to the Montreal Protocol about ways the use of methyl bromide can be controlled. The expert advisors to the Parties to the Protocol, the Methyl Bromide Technical Options Committee, has been asked to look at alternatives. The Committee will report in 2003.

To view Montreal Protocol reports on methyl bromide visit the “Technology and Economic Assessment Panel” website reports page and scroll to the rows that have MBTOC in left hand column. See the annual TEAP reports for updates on methyl bromide issues.

Last updated: 14 April 2005