Methyl bromide has been the default fumigant for timber and wood packaging material for decades. It kills insects, nematodes, fungi, and other organisms reliably across a wide range of conditions. It also depletes the ozone layer, which is why the Montreal Protocol has been systematically phasing it out since 2005. Quarantine and pre-shipment exemptions are narrowing, and timber exporters who haven’t started transitioning are running out of runway.

The core problem is straightforward: methyl bromide works exceptionally well, and finding replacements that match its broad-spectrum efficacy has proven difficult. But regulatory reality doesn’t wait for perfect substitutes.

Heat Treatment Under ISPM 15

Heat treatment is already the primary alternative for wood packaging material under ISPM 15. The standard requires heating wood to a core temperature of 56 degrees Celsius for at least 30 minutes, killing most regulated pests.

The advantages are significant. No chemical residues, no gas monitoring, and no occupational exposure risk. Kiln-dried timber that reaches the required temperature during normal processing already meets the standard without an additional treatment step.

The limitations are real too. Heat treatment demands significant energy input for large-dimension timber. Not all facilities have kilns large enough for commercial volumes. But capital costs are front-loaded while operating costs remain predictable, making it the most practical path for many export operations.

Sulfuryl Fluoride

Sulfuryl fluoride is the most established chemical alternative for timber treatment. It penetrates wood effectively, kills a broad range of insects including dry-wood termites and bark beetles, and doesn’t deplete ozone.

However, it’s a potent greenhouse gas with an atmospheric lifetime of roughly 36 years. Replacing one environmentally problematic fumigant with another raises questions about long-term viability. From a practical standpoint, exposure times are longer than methyl bromide, and it’s less effective against fungal pathogens and nematodes. Some importing countries don’t yet recognize it as an approved quarantine treatment, limiting its use in certain export corridors.

Phosphine

Phosphine fumigation has been used in grain storage for decades and is being evaluated for timber applications. It’s effective against many insect pests, relatively inexpensive, and doesn’t have ozone-depleting properties.

The drawbacks are substantial. Phosphine is acutely toxic to humans and requires careful handling. Treatment times stretch to several days. It doesn’t penetrate wood as quickly as methyl bromide, and efficacy drops significantly below about 15 degrees Celsius. For situations where longer treatment times are acceptable, particularly in warmer climates, it remains a viable option.

Ethanedinitrile (EDN)

EDN is among the most promising newer fumigants being developed specifically as a methyl bromide replacement. It penetrates wood effectively, works across the pest spectrum including fungi and nematodes, and breaks down into relatively benign compounds.

New Zealand has led EDN development, with commercial trials on export logs showing efficacy comparable to methyl bromide. Australia and several other countries are evaluating registration applications. The challenges are typical of new chemical registration: toxicological data requirements, equipment development, and worker safety protocols. EDN is supplied as a pressurized liquid and vaporized during application, meaning fumigation operators will need new equipment and training.

Non-Chemical Approaches

Controlled atmosphere treatments manipulate oxygen, carbon dioxide, and nitrogen levels to create conditions lethal to pests. The principle is sound, but scaling to commercial timber volumes is technically demanding. Treatment times of days to weeks make this impractical for time-sensitive shipments, though container-based nitrogen injection systems for in-transit treatment are being piloted.

Dielectric heating—using microwave or radio frequency energy to heat wood internally—achieves pest kill faster than conventional heat treatment by heating the interior directly. Commercial systems exist for small-dimension products like pallet components. Radio frequency heating penetrates deeper and shows promise for larger timber, with several research groups developing continuous-flow treatment systems.

Planning the Transition

Timber exporters should approach the methyl bromide transition strategically. Different alternatives suit different products, markets, and supply chain configurations. Heat treatment may be optimal for wood packaging while EDN or sulfuryl fluoride handles log fumigation. Multiple approaches may be needed across a diversified export program.

Market access is the critical variable. Not all alternatives are accepted everywhere, and a compliant treatment that isn’t recognized at the receiving port is worthless. Verifying that an alternative meets the phytosanitary requirements of each destination market is non-negotiable.

Building heat treatment capacity, securing permits for new fumigants, and training operators all take time. The methyl bromide era in timber treatment is ending. Exporters who start evaluating and implementing alternatives now will be better positioned than those who wait until forced to act.