Heat-treated pallets have been heated until the wood core reaches at least 56 degrees Celsius for at least 30 minutes, then stamped under ISPM 15. Export loads need them because the international standard regulates wood packaging in trade.
ISPM 15 regulates wood packaging material in international trade. Heat treatment requires the wood core to reach at least 56 °C (133 °F) for a minimum of 30 minutes. The wood must also be debarked before treatment; allowed bark must be less than 3 centimetres wide, or if wider, under 50 square centimetres in area.
The mark is the evidence. Without it, a customs officer abroad has no way to know whether the wood was treated.
| Load | HT needed? | Notes |
|---|---|---|
| Domestic, within the US | No | Untreated Grade A or B is fine |
| Export to most countries | Yes | Wood packaging must carry the ISPM 15 mark |
| To Canada from the continental US | Exempt at present | Canada's CFIA exempts wood packaging from the continental US, pending a phased move to full ISPM 15 |
| Imported equipment going back out | Check the mark | A legible original stamp can be reused; a painted-over one cannot |
Check current rules at the destination before you ship. Requirements change by country and nothing here is legal advice. The exporting equipment guide covers the rules in more detail.
Heat treatment kills pests but does not make wood immune to mold. Pallets loaded into trailers while still hot are susceptible to mold, and wood stored above 20 percent moisture will support it. Ask that heat-treated stock be dry before it ships, and give it air: even a slight air velocity of a few feet per second can help prevent mold on stored pallets.
Say the size, the count and where the load is going.
Yes for most destinations. ISPM 15 requires the mark on wood packaging in international trade.
A repaired pallet may no longer qualify. Repairs can break the treatment, so re-treatment and re-marking are needed for export.
Sources, last reviewed 12 November 2026