ISPM-15 & Heat Treatment: What Every Exporter Must Know

Of all the ways an export shipment can go sideways, the pallet under it is the most avoidable. ISPM-15 is not obscure and it's not new, yet non-compliant wood packaging strands freight at borders every single day. If you ship anything internationally on wood, this is a rule you cannot delegate to luck.

What ISPM-15 actually is

ISPM-15 — International Standards for Phytosanitary Measures No. 15 — is a global standard developed under the International Plant Protection Convention. Its purpose is narrow and important: stop solid wood packaging material from ferrying invasive insects and fungi across borders. The infamous examples are the pine wood nematode and the Asian long-horned beetle, both of which have hitched rides in untreated pallets and done real ecological and economic damage.

The standard covers pallets, crates, dunnage, and other solid wood packaging. It does not cover processed materials like plywood or oriented strand board, which are manufactured with enough heat and adhesive to already be considered safe.

HT vs. MB: the two treatments

ISPM-15 recognizes two main treatment methods, and the difference matters for both safety and marketability.

• HT — Heat Treatment. The wood core is heated until it reaches a minimum of 56°C (about 133°F) for at least 30 continuous minutes. This kills pests without chemicals. HT is by far the dominant method and the one we use and recommend.
• MB — Methyl Bromide fumigation. A chemical fumigant that also kills pests but is an ozone-depleting substance, banned or restricted in many countries and phased out under the Montreal Protocol. Increasingly, destination countries reject MB-marked wood.

For practical purposes today, treat HT as the standard and MB as the option to avoid. Heat treatment is cleaner, more widely accepted, and doesn't leave a chemical question mark on your load.

Reading the stamp

The compliance mark is a small branded or stamped emblem on the pallet, and knowing how to read it saves you from trusting a seller's word.

1. 1The IPPC 'wheat' logo — a stylized ear of grain — confirms the mark is an ISPM-15 stamp, not a random brand.
2. 2A country code (for example US) identifies where treatment happened.
3. 3A unique facility number identifies the accredited treatment provider.
4. 4A treatment code — HT for heat treatment, MB for methyl bromide, DB for debarked.

If any of those elements is missing, faked, or the wood is visibly re-marked over an old stamp, treat the pallet as non-compliant. A grade label is not a treatment stamp — those are two different things, as we explain in how pallets are graded.

“Customs doesn't inspect your product first — they inspect the wood it's sitting on. Get the pallet wrong and they never reach the cargo.”

Why customs cares so much

From a border agency's view, a pallet is a potential vector for a biological invasion, and the cost of one bad beetle establishing itself can run into the billions in eradication and lost timber. That asymmetry is why enforcement is unforgiving: an inspector who waves through untreated wood risks a catastrophe, so the default answer to a missing stamp is 'no.' Depending on the country and the officer, non-compliant wood can be refused entry, treated on arrival at your cost, or destroyed outright — sometimes taking the shipment with it.

Sourcing compliant pallets

The good news: any grade of pallet can be heat-treated, so compliance doesn't force you into buying new. A sound reclaimed pallet, heat-treated and properly stamped, is fully export-legal. What matters is that the treatment is done by an accredited facility and the stamp is genuine. We supply HT-stamped reclaimed and remanufactured pallets built to ship abroad, and if you'd rather we spec an export truckload end to end, start here.

Common mistakes exporters make

• Assuming a clean, new-looking pallet is treated — cosmetics have nothing to do with compliance.
• Mixing one untreated pallet into an otherwise compliant load and getting the whole shipment held.
• Reusing an HT pallet after a repair with untreated lumber — a repair can void compliance unless done with treated wood and re-stamped.
• Accepting MB-marked wood for a country that rejects it.
• Confusing 'kiln dried' (KD) with heat treated — KD alone does not satisfy ISPM-15 unless it also meets the HT profile and is stamped.

Get these five right and you'll almost never see a phytosanitary hold. When in doubt, ask us to verify a stamp or spec a compliant load — it's a lot cheaper than a refused container.