Heat Treatment (HT): Chemical-Free Pest Control for Wood Pallets

Heat treatment (HT) is a chemical-free method of treating wood that kills insects, eggs and microorganisms by heating the timber to a core temperature of at least 56C for a minimum of 30 minutes. It meets the international ISPM 15 standard, lets wood packaging clear customs in more than 100 countries, and lowers moisture to make pallets more durable. Treated pallets carry the HT mark to confirm compliance.

What is heat treatment (HT)?

Heat treatment (HT) is a process that treats wood without any chemicals, killing insects, insect eggs and parasitic microorganisms that can live inside timber. Under the ISPM 15 standard (International Standards for Phytosanitary Measures No. 15), the wood is heated to a defined temperature and held there for a required time.

After treatment, the wood pallet is stamped with the HT certification mark to confirm the process fully complied with ISPM 15, protecting importing countries from the biosecurity risk of invasive organisms. For the full standard, see what the ISPM 15 standard is.

Why is heat treatment (HT) important?

Global biosecurity protection

Untreated wood is an ideal shelter for harmful insects and microorganisms. When pallets cross borders, they can carry invasive species into new countries and cause serious damage to native ecosystems, agriculture and forestry. HT eliminates these threats so a wood pallet never becomes a vector for pests and disease.

Compliance with the international ISPM 15 standard

ISPM 15 is a mandatory requirement for wood packaging material in international trade. IPPC member countries will reject non-compliant shipments or order them re-treated. Failure to comply can mean a shipment is held, destroyed, or hit with costly penalties and extra handling, disrupting the supply chain and damaging a company’s reputation.

Protecting cargo quality

Besides killing pests, the heat process reduces the moisture content of the wood. Lower moisture makes pallets more durable and less prone to mould and rot, giving better protection to goods carried on them, especially moisture-sensitive items such as food, pharmaceuticals and electronics.

No toxic chemicals

Unlike the older methyl bromide (MB) fumigation method, HT uses no toxic substances. The treated wood stays safe for people and the environment, in line with sustainability goals and increasingly strict environmental regulations worldwide.

How the heat treatment (HT) process works

A proper heat treatment process follows strict steps to ensure maximum effectiveness.

Benefits of heat-treated (HT) wood pallets

Using heat-treated wood pallets brings several practical benefits to a business:

• Safe for cargo and people: no toxic chemicals, keeping both products and workers safe.
• Smooth international trade: HT pallets are accepted in more than 100 countries and territories, so exports and imports run without interruption.
• Longer pallet life: drying reduces moisture and increases the hardness and load-bearing capacity of the wood, extending service life.
• Environmentally friendly: heat treatment is a sustainable method that does not pollute the environment.

For more on these and other compliance marks, see our wood pallet range.

Frequently asked questions about heat treatment (HT)

1. What temperature and time does HT require?

The wood core must reach a minimum of 56C (132.8F) and hold for at least 30 minutes continuously. Core sensors confirm the temperature, not just the surrounding air, so the whole thickness of the timber is treated.

2. How is HT different from methyl bromide (MB) fumigation?

HT uses only heat and no chemicals, leaving the wood safe for people and the environment. MB is a chemical fumigant that is being phased out in many countries for health and environmental reasons. Both can satisfy ISPM 15, but HT is the preferred, sustainable choice.

3. Does an HT pallet need an HT stamp?

Yes. A treated pallet must carry the HT certification mark, which includes the IPPC symbol, the country code, a registered supplier code and the HT treatment code. The stamp is how customs verifies compliance without re-testing the wood.

4. Which countries accept HT pallets?

HT pallets that comply with ISPM 15 are accepted in more than 100 countries and territories, including the United States, the EU, Japan, Australia and most major trading nations that are IPPC members.

5. Does heat treatment damage the wood or weaken the pallet?

No. Controlled drying to 56C reduces moisture, which actually increases hardness and load-bearing capacity and lowers the risk of mould and rot, extending the pallet’s service life rather than shortening it.

6. What happens if a shipment uses non-compliant wood packaging?

Member countries may reject the shipment, order re-treatment, hold or destroy the goods, and apply penalties and extra handling costs. This disrupts the supply chain and can harm the exporter’s reputation, so HT certification should be confirmed before shipping.

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