Methyl bromide fumigation is an alternative ISPM-15 treatment, increasingly restricted due to environmental impact.
Detailed Definition
Methyl bromide (MB) is a fumigant gas approved under ISPM 15 as a treatment for wood packaging, marked with the code MB. ISPM 15 sets a minimum concentration-time product over an exposure of at least 24 hours, with required values that depend on wood temperature, so treaters must follow the schedule in the standard's annex rather than a single dose. Methyl bromide depletes the ozone layer and is controlled under the Montreal Protocol; most uses were phased out, but quarantine and pre-shipment uses such as ISPM 15 were exempted. In the US, heat treatment is the more common choice.
How MB treatment works and how it is marked
Wood packaging is placed under a gas-tight tarp or in a chamber, the gas is introduced, and concentrations are measured during the exposure to show that the required concentration-time product was reached. The wood must be debarked and be above the minimum temperature in the standard. After treatment the load is aerated before handling. Compliant packaging carries the IPPC mark with the country code, producer or treatment provider number, and the code MB.
Why it is being phased down
The IPPC has encouraged countries to reduce or replace MB use where alternatives exist, and some countries restrict or do not permit MB treatment within their borders. Heat treatment (HT) and dielectric heating (DH) avoid the ozone and worker exposure concerns. Methyl bromide is also highly toxic to people, so fumigation must be done by licensed applicators following the product label and local pesticide rules.
What exporters should check
- Whether the importing country accepts MB-marked packaging or prefers HT.
- That the mark is legible and on at least two opposite sides.
- That any repaired pallet with new wood has been re-treated and re-marked as required.
Authoritative Sources
- US Environmental Protection Agency (EPA): the federal agency that implements the US phaseout of ozone-depleting substances such as methyl bromide; this page describes its non-hazardous materials management hierarchy.
- International Plant Protection Convention (IPPC): the international plant health treaty, with a secretariat hosted by FAO, whose Commission on Phytosanitary Measures adopts ISPM 15.
- FAO ISPM-15 Standard (ISPM-15): the international phytosanitary standard for wood packaging used in international trade, published by the FAO.
Related Glossary Terms
Frequently Asked Questions
Are methyl bromide treated pallets still accepted for export?
MB remains a treatment listed in ISPM 15, and MB-marked wood packaging is generally recognized by countries that follow the standard. However, some countries restrict methyl bromide use or encourage alternatives, and requirements can change. Because heat treatment is widely available in the US and avoids these questions, most exporters choose HT-marked pallets. Check the importing country's current rules if you receive or plan to use MB-treated packaging.
Is methyl bromide fumigation the same as heat treatment?
No. Heat treatment kills pests by holding the wood core at 56 C for at least 30 continuous minutes, and it is marked HT. Methyl bromide fumigation uses a toxic gas held at a required concentration for at least 24 hours, and it is marked MB. Both are approved ISPM 15 treatments, but MB has ozone and safety concerns, and neither treatment prevents the wood from being reinfested or growing mold later.