Every pallet that can legally cross a border carries a stamp. If you ship export freight, that stamp is the difference between cargo that clears and cargo that gets refused, fumigated at your expense, or sent back. If you don’t ship export, the stamp still tells you what the wood has been through. Here’s how to read it.
The IPPC / ISPM-15 stamp
International shipments of wood packaging fall under ISPM-15, a standard from the International Plant Protection Convention (IPPC) designed to stop pests hitching a ride in raw lumber. A compliant pallet carries a stamp with four parts:
[IPPC wheat-ear logo] US - 000
HT
- The IPPC logo. A stylized wheat stalk inside a rectangle. If the logo is missing, the mark is not an ISPM-15 mark.
- Country code. Two letters, ISO format.
USfor the United States,CACanada,MXMexico,CNChina. - Producer or treatment provider number. Assigned by the national plant protection organization, in the U.S. through the American Lumber Standard Committee (ALSC) program. It identifies who treated the wood and can be traced.
- Treatment code. What was done to the wood. This is the part most people are asking about.
Treatment codes
| Code | Meaning | What it tells you |
|---|---|---|
| HT | Heat Treated | Wood core reached 56°C (132.8°F) for at least 30 minutes. Kills pests and larvae. No chemicals involved. The standard for export pallets today. |
| MB | Methyl Bromide | Fumigated with methyl bromide gas. Still accepted under ISPM-15 but phased out in many countries and banned for most uses in the U.S. and EU. Do not chip MB pallets for mulch or burn them. |
| DH | Dielectric Heating | Heated with microwave or radio frequency energy to the same 56°C target. Compliant, less common. |
| SF | Sulfuryl Fluoride | Fumigation alternative to MB, added to the standard in 2013. Rare on pallets. |
Only these codes are ISPM-15 treatments. If you’re shipping export, your pallet must show one of them alongside the IPPC logo.
Marks that are NOT ISPM-15 treatments
KD (Kiln Dried). The lumber was dried in a kiln to reduce moisture, typically to 19 percent or below. This controls warping and mold. It does not by itself make a pallet export-compliant, because kilns don’t necessarily hit 56°C at the core for the required time. You will often see KD-HT together, meaning both were done, and that pallet is compliant because of the HT half.
DB (Debarked). Bark was removed. ISPM-15 requires debarked wood, so DB often appears next to HT, but on its own it’s not a treatment.
Company logos, grade stamps, recycler marks. Plenty of pallets carry a manufacturer’s brand or a “Grade A” stencil. These are informational and mean nothing to customs.
“Are pallets pressure treated?”
Almost never. Pressure treating (forcing preservative chemicals into the wood, the green-tinted lumber used for decks) is not an ISPM-15 method and isn’t used on pallets because it’s expensive and unnecessary for a product meant to carry freight, not survive outdoors for 20 years. If you’re asking because you want to reuse pallet wood: an HT pallet is heat and nothing else. An MB pallet was fumigated and should not be used indoors, burned, or cut for projects. A pallet with no stamp has an unknown history.
What a valid stamp looks like in practice
- Logo, country code, provider number, and treatment code all present and legible
- Stamped on at least two opposite sides of the pallet
- Applied by a certified facility (in the U.S., one audited under the ALSC program)
A faded or partial stamp is a customs risk. Repaired pallets are a particular case: if a stringer or deck board was replaced, the replacement wood must also be treated and the pallet re-stamped by a certified facility, or the original mark should be obliterated. A recycled pallet with an old HT stamp and an untreated replacement board is technically non-compliant, and some ports check.
What this means if you export from DFW
- Ask your supplier specifically for ISPM-15 heat-treated, stamped pallets, not just “heat treated.”
- Check the stamp on the pallets when they arrive. Logo, country, number, HT.
- If pallets are repaired before reuse for export, confirm the repair shop is certified to re-stamp.
A supplier should be able to tell you, without hesitation, who applies the stamp and under what certification. If the answer is vague, the stamp may be too.
Frequently asked questions
Heat Treated. The wood core was held at 56°C for at least 30 minutes to kill pests, with no chemicals. HT is the standard treatment for ISPM-15 export pallets.
The pallet was treated to the ISPM-15 international standard for wood packaging. The stamp shows the IPPC logo, a country code, a certified producer number, and a treatment code such as HT or MB.
Not on its own. KD means kiln dried, which controls moisture but isn’t an ISPM-15 treatment. KD-HT together is compliant.
Yes. Heat treatment uses no chemicals. Pallets marked MB were fumigated and should not be burned or repurposed.
Need stamped export pallets in Dallas–Fort Worth?
A&A Pallets supplies ISPM-15 heat-treated, stamped pallets and skids in standard and custom sizes for exporters across DFW. Call (214) 398-3555.
Related services: Heat-Treated Pallets · Custom Pallets · Pallet Repair · All services
Photo: oaktree_brian_1976 via Wikimedia Commons, CC BY-SA 2.0 (source)
