Heat-treated pallets for loads leaving the country
A heat-treated pallet has had its wood core held at 56 degrees Celsius or higher for at least 30 minutes and carries the HT mark of the ISPM 15 stamp.
- Size
- 48x40, 48x48, Euro
- Build
- Stringer or block
- Grade
- Heat-treated, stamped
- Trades
- Export, medical, machinery
- Towns
- Grand Rapids to the lakeshore
What the HT mark means
ISPM 15 is the international standard for wood packaging that crosses borders. It regulates wood packaging material in international trade. Heat treatment is one of its approved treatments: the wood core must reach at least 56 degrees Celsius (133 degrees Fahrenheit) and hold it for a minimum of 30 minutes. The wood must also be debarked first; allowed bark is narrow, less than 3 cm wide, or if wider, under 50 square centimetres of surface.
The result is a stamp on the pallet. The HT stamp guide reads each part of it.
Which loads need it
| Where the load goes | Pallet needs | Check |
|---|---|---|
| Overseas | ISPM 15 stamp, usually HT | The receiving country's rules |
| Canada | US-origin wood packaging is currently exempt from CFIA policy D-98-08 | CFIA guidance |
| Within the US | No ISPM 15 stamp needed | Your customer's own packaging sheet |
The Canada row is worth reading closely. The Canadian Food Inspection Agency says wood packaging from the continental United States is exempt from policy D-98-08, pending a phased move to full ISPM 15 implementation. That is the position today; it is not a promise about next year. The Canada guide keeps the details and a review date.
Two cautions that save a load
Heat treatment does not make wood immune to mould. A heat-treated pallet loaded into a trailer while still hot is susceptible to it. If you ship in humid weather, ask for dry stock and see the moisture guide.
The stamp belongs to the producer that treated the wood, so ask for the stamp you need and check it on the pallet at the dock.
What to put in the request
- Destination country, because it decides what the stamp must say
- Pallet size: 48x40, 48x48 or the Euro 800 x 1200 mm are the usual export sizes
- New or used, and the grade if used
- Count and the shipping date, if it is fixed
- Whether the pallet must also be clean and dry for a food or medical load
A closer look at the stamp
A heat-treated pallet is marked with the IPPC symbol, a country code, a producer number and the code HT. The code DB shows the wood was debarked, which ISPM 15 requires before treatment. The other approved treatment, fumigation with methyl bromide, is marked MB. The HT stamp guide reads each part in turn.
Debarking and the bark rule
ISPM 15 lets a little bark stay on. Strips under 3 centimetres wide are allowed, and wider strips must cover under 50 square centimetres. A pallet with more bark than that does not meet the rule, however it was treated.
After treatment, keep it dry
Heat treatment leaves a dry pallet, but it does not make wood immune to mould. A treated pallet loaded into a trailer while still hot can sweat as it cools. Air movement of a few feet per second is enough to prevent it, so stack with gaps and let the stack cool before loading.
Who should buy treated stock
- Any plant shipping by sea or air to another country
- Exporters whose receiving customer asks for the mark even when the border does not
- Anyone unsure: confirm with the receiver, then buy once
Domestic loads do not need the stamp. For Canada, read shipping to Canada, and for sizes used abroad see the Euro pallet.
Cost and lead time
Heat treatment adds a step: the wood must go through a chamber and be held at temperature. That takes time and costs money, and a request with a short deadline should say so early. A treater has to be certified to apply the mark, which is why not every seller can supply it.
Used pallets and the stamp
A used pallet may still carry a mark from its first life. That mark is valid only if the pallet has not been repaired with untreated lumber. Exporters often avoid the problem by buying new, marked stock for each shipment. Where a used marked pallet is acceptable, ask the seller to confirm that nothing has been replaced.
Also check whether the receiving country accepts fumigated wood marked MB, or only heat-treated wood marked HT. Many shippers prefer HT.
When heat-treated is required and when it is not
Heat treatment is required for wood packaging that crosses many national borders, and some customers require it for domestic freight too. Check the receiver's rules before buying, since a pallet without the mark can be refused at a border or at a dock.
For purely domestic freight with no such rule, an untreated pallet may be enough and cost less. The mark is the proof, so look for it on each pallet, not on the invoice alone, and ask how any repairs were made.
Reading an invoice
A proper invoice names the material as heat-treated wood packaging and gives the producer, but the mark on the pallet is the proof. Keep both. If an auditor or a customer asks, the invoice shows what you bought and the mark shows what you received.
Mixed lots are a risk. A pallet repaired with untreated boards can lose its standing, so ask the seller how repairs are handled in the lot you are buying.
Why the treatment exists
The rule was written to stop wood-boring insects and plant disease travelling in packing timber between countries. The wood is held at a core temperature for a set time, which kills what lives inside. That is why a mark, rather than an appearance, is the evidence.
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Last reviewed 12 November 2026.