An ISPM 15 stamp is the IPPC mark that shows the wood in a pallet, crate or piece of dunnage was treated against pests by an approved method. Read it left to right: the wheat-ear symbol, the two-letter country code (US, BR, CN), a hyphen, the producer or treatment provider number, and the treatment code (HT, DH, MB or SF). The codes are the easy part. Shipments get held for what sits around them.
What the ISPM 15 stamp is
It is the mark set out in Annex 2 of ISPM 15, the International Standard for Phytosanitary Measures on wood packaging material in international trade. The standard is published by the IPPC (International Plant Protection Convention), part of the UN’s FAO.
The mark makes one claim: this packaging is made of debarked wood, treated by an approved method, by a producer registered with the national plant protection organization (NPPO) of the country. In the US that is USDA APHIS; in Brazil it is the Ministry of Agriculture (MAPA). It applies to solid wood packaging: pallets, crates, boxes, cable drums and dunnage (the loose wood used to brace cargo in a container).
Packaging made entirely of processed wood such as plywood, OSB or particleboard is outside the standard, and so is wood 6 mm thick or less. That is why an all-plywood pallet carries no mark and a pallet with solid wood blocks does.
How to read the IPPC mark, field by field
The mark has four required components, always in this order:
| Field | Example | What it means |
|---|---|---|
| Symbol | the wheat ear with the letters IPPC | the official IPPC symbol, always to the left of the codes |
| Country code | US | the ISO two-letter code of the country where the wood was treated |
| Producer code | 000 | a unique number the NPPO assigned to the packaging producer or treatment provider |
| Treatment code | HT | the approved treatment, using the Annex 1 abbreviation |
On the pallet it looks like this: symbol on the left, a vertical line, and on the right US-000 on one line and HT on the line below. The treatment code may also sit on the same line, separated by a hyphen (US-000-HT).
The producer code is the field that traces the pallet back. With it, the NPPO can identify the company that marked the packaging. Each country sets the number of digits and the order of letters and numbers, so a Brazilian code does not look like a US one.
What HT, DH, MB and SF mean on a pallet
These are the four treatments approved in Annex 1 of ISPM 15:
| Code | Treatment | Main requirement |
|---|---|---|
| HT | heat treatment | core of every piece at 56 °C for 30 continuous minutes |
| DH | dielectric heating (microwave or radio frequency) | 60 °C for 1 continuous minute through the whole piece, surface included; wood up to 20 cm in its smallest dimension |
| MB | methyl bromide fumigation | fumigant gas; the IPPC recommends reducing and replacing its use |
| SF | sulphuryl fluoride fumigation | fumigant gas added to the standard in the 2018 revision |
On export pallets from Brazil and most of the Americas, the code you will see is almost always HT. For fumigation (MB and SF), bark must come off before treatment because it reduces how well the gas works. For heat treatment, bark can be removed before or after.
What can appear outside the border: DB, KD and the agency logo
The Annex 2 rule is short: inside the border, only the four components. Anything else goes outside, next to the mark.
- DB (debarked). Found on older marks. The current standard requires debarked wood for every treatment, so DB is no longer a required component. The bark tolerance is small: pieces narrower than 3 cm, or wider pieces with no more than 50 cm² each.
- KD (kiln dried). It refers to moisture content, not pest treatment. In the US, ALSC rules allow KD next to HT when the lumber was dried to the limit set in the grading rules.
- Inspection agency logo or producer trademark. In the US, pallet marks carry the symbol of the accredited agency that audits the plant. The standard allows it, as long as it sits outside the border.
The standard also tells importing countries to accept packaging marked under earlier versions. An older pallet stamped DB is not a non-compliant pallet.
How to tell if an ISPM 15 stamp is non-compliant
Use this checklist when pallets arrive from a supplier or before you load a container. Every item comes from Annex 2 of ISPM 15:
- The IPPC symbol is there, to the left of the codes.
- There is a rectangular or square border and a vertical line between the symbol and the codes (small stencil gaps are allowed).
- The country code and the producer code are separated by a hyphen.
- The treatment code is one of four: HT, DH, MB or SF.
- Nothing other than the four components sits inside the border.
- It is legible without a magnifier and is not hand drawn.
- It is durable and does not transfer (ink that smears in the first rain does not count).
- It is not red or orange, colours reserved for dangerous goods labels.
- It is visible when the pallet is in use, preferably on two opposite sides.
- Every piece of dunnage carries a complete mark. A cut piece that lost part of the mark should not be used.
The last item is the one that slips through at the loading dock. Dunnage is often cut to length only when the cargo is braced, and the cut can land in the middle of the mark. The standard recommends marking dunnage at short intervals along its whole length, so every cut piece keeps a full mark.
What the 2026 US hyphen rule changes
Since January 1, 2026, APHIS and CBP have resumed enforcement of the hyphen between the country code and the producer code. From March to December 2025, enforcement was suspended for shipments missing only the hyphen; every other ISPM 15 requirement stayed in force throughout.
In practice, a pallet stamped “XX 000” instead of “XX-000” can be treated as non-compliant at a US port. If your pallet supplier still uses an old stamp, check it before the next shipment. Rules checked in November 2026.
Does lumber need an ISPM 15 stamp?
Not in the way a pallet does. ISPM 15 regulates wood packaging. Lumber traded as a commodity follows the phytosanitary requirements of the importing country, which may ask for a phytosanitary certificate, a treatment or an inspection. The international movement of wood as a commodity is covered by a different IPPC standard, ISPM 39.
For export pallet makers, what matters is the chain: lumber treated with a time and temperature record, and the mark applied to the finished pallet by a registered facility. In the US, ALSC rules require accredited pallet plants to use HT or KD-HT lumber. We explain the difference between drying (KD) and treating (HT) in kiln dried and heat treated lumber for pallets, and which grade each line can take in pine lumber grades explained.
How LG Madeiras does it
LG has run its own kilns since 2017, with drying controlled by the EcoPower MR500 system from Marrari, which records every cycle. In 2023 our kiln was audited and approved under the heat treatment program of Timber Products Inspection (TPI), an agency accredited by the American Lumber Standard Committee (ALSC). Our sawn pine leaves the kiln at 5% to 12% moisture content, and with FSC® certification (licence FSC-C215210) when the order is certified.
We supply pallet and packaging plants in Brazil and abroad, shipping in containers from the ports of Itajaí and Navegantes. See how we produce KD-HT sawn pine lumber.
Sources: ISPM 15, Regulation of wood packaging material in international trade (IPPC/FAO), Annexes 1 and 2, revision adopted in 2018; ISPM 39 (IPPC, 2017); APHIS stakeholder notice on the end of the hyphen enforcement suspension (December 2025); ALSC Wood Packaging Material Enforcement Regulations (November 2025). Information checked in November 2026.