A single untreated pallet under an otherwise perfect shipment can hold up an entire container at the port of entry. ISPM 15 is the reason why — and it is one of the most consistently misunderstood standards in international trade, precisely because it looks simple on the surface. This article sets out, in one place, when it applies, what is exempted, the debarking requirement, the approved treatments, the mark, and where national import controls diverge from the base standard.
- What ISPM 15 is, and why it exists
- Scope — what counts as wood packaging material
- What is exempted
- The debarking requirement
- Approved treatments — HT, DH, MB, SF
- The IPPC mark
- Import controls — where countries diverge from the base standard
- Validity, reuse, repair and remanufacture
- Common errors that cause rejections
- References
1. What ISPM 15 is, and why it exists
ISPM 15 is International Standard for Phytosanitary Measures No. 15, issued by the International Plant Protection Convention (IPPC) under the UN Food and Agriculture Organization. It targets one specific vector: raw wood used as packaging — crates, boxes, packing cases, dunnage, pallets, cable drums and spools/reels — which can carry pests posing a risk mainly to living trees, and can be present in almost any imported consignment, including ones that would never otherwise be subject to phytosanitary inspection.
The standard exists because it works. Two of the most cited introductions of forest pests into new ecosystems — the Asian long-horned beetle and the brown marmorated stink bug — travelled internationally in solid wood packaging, not in the cargo it was protecting. ISPM 15 is explicit that its measures are not intended to provide ongoing protection from re-infestation — it requires that the wood be treated and marked once, at the point of manufacture or treatment, and that mark is what NPPOs of importing countries are expected to accept as the basis for entry without a separate phytosanitary certificate for the wood packaging itself. The IPPC has over 180 contracting parties, each with its own National Plant Protection Organisation (NPPO) responsible for implementing the standard domestically.
2. Scope — what counts as wood packaging material
ISPM 15 applies to raw (unprocessed) softwood and hardwood used to support, protect or carry cargo, above 6 mm in thickness. The standard’s own list of covered material is:
- Crates, boxes and packing cases
- Dunnage — loose wood used for blocking, bracing and securing cargo inside a container or hold
- Pallets
- Cable drums and spools/reels
The standard is not a general cargo rule — it applies regardless of what the wood is packaging or supporting. A container of steel fittings with two untreated dunnage boards wedged against the door is just as non-compliant as a shipment of raw timber itself. One narrow exception: wood components permanently attached to freight vehicles and containers — such as a container’s own wooden floor — are exempted (see Section 3), precisely because they are part of the conveyance rather than packaging accompanying the cargo.
Stacked export pallets. Photo: Rivermann, via Wikimedia Commons, licensed under CC BY-SA 4.0.
3. What is exempted
Not every piece of wood in a shipment needs treatment and marking. The standard sets out specific, low-risk exemptions:
- Thin wood — 6 mm or less in thickness, regardless of species.
- Processed wood-based products — plywood, particle board, oriented strand board (OSB) and veneer manufactured using glue, heat, pressure, or a combination of these — because the manufacturing process itself is enough to eliminate pests.
- Wine and spirit barrels that have been heated during manufacture.
- Gift boxes for wine, cigars and similar commodities made from wood processed in a way that renders it pest-free.
- Sawdust, wood shavings and wood wool — too small to harbour wood-boring insects.
- Wood components permanently attached to freight vehicles and containers — for example, a container’s built-in wooden flooring, since it is part of the conveyance and not packaging accompanying the cargo.
4. The debarking requirement
Since the 2009 revision, ISPM 15 requires that wood packaging material be made from debarked wood, irrespective of which treatment is applied afterwards. Debarking is a mechanical process — teeth, knives or chains tearing bark from the harvested log — and it does not have to leave the wood completely bark-free. The standard allows:
- Any number of separate, clearly distinct patches of bark are permitted, provided each individual patch meets one of these two conditions:
- Each patch is less than 3 cm in width (regardless of length), or
- Each patch is wider than 3 cm, provided that patch’s own surface area does not exceed 50 cm²
In other words, a stringer with several small compliant patches of bark is not over-treated as non-compliant just because there is more than one patch — each patch is assessed against the size limits individually, not summed across the piece.
The sequencing matters and differs by treatment method. For methyl bromide and sulphuryl fluoride fumigation, debarking must be completed before treatment in both cases, because bark on the wood can affect treatment efficacy. For heat treatment (including dielectric heating), debarking may be carried out before or after — but where a dimension limit applies to the method (as it does for dielectric heating), any remaining bark must be included when that dimension is measured.
5. Approved treatments — HT, DH, MB, SF
As of the CPM-13 revision (April 2018), four treatment methods are recognised under ISPM 15 Annex 1, each with its own mark code:
| Code | Treatment | Core requirement | Notes |
|---|---|---|---|
| HT | Heat treatment (conventional) | Wood core reaches 56°C for a minimum of 30 continuous minutes throughout its profile | The most widely accepted method; no ozone-depletion or residue concerns |
| DH | Dielectric heating | Entire wood profile must reach 60°C, achieved within 30 minutes of the start of treatment, and held for at least 1 continuous minute | Faster than conventional HT; suited to smaller batches or individual pieces |
| MB | Methyl bromide fumigation | Minimum concentration-time (CT) product of 650 g·h/m³ over 24 hours at 21°C or above (final concentration ≥24 g/m³) — higher CT/final-concentration figures apply at lower temperatures (down to a floor of 10°C, below which MB may not be used at all). An illustrative dosage schedule achieving this is 48 g/m³ initial dose at ≥21°C. | Must not be used on wood exceeding 20 cm in cross-section at its smallest dimension; debarking required before treatment; minimum exposure time 24 hours; increasingly restricted or refused at destination on environmental grounds (see Section 7) |
| SF | Sulphuryl fluoride fumigation | Minimum CT of 1,400 g·h/m³ over 24 hours at 30°C or above (final concentration ≥41 g/m³), or 3,000 g·h/m³ over 48 hours at 20°C or above (final concentration ≥29 g/m³). Wood temperature must not fall below 20°C at any point during treatment, including at the core. | Added as an approved treatment by CPM-13 (2018); must not be used on wood exceeding 20 cm in cross-section, or with moisture content above 75% (dry basis); debarking required before treatment |
6. The IPPC mark
Once treated, wood packaging must carry the official mark before it can be used — no phytosanitary certificate is required for the wood packaging itself, because the mark serves as the compliance evidence. The mark must be permanently and legibly applied, typically on at least two opposite sides of the unit, and consists of:
- The IPPC logo (a stylised wheat/plant symbol), always positioned to the left, inside a rectangular border with a vertical divider line separating it from the rest of the mark.
- A two-letter ISO country code identifying where the treatment was carried out.
- A unique producer/treatment-provider registration number, assigned by the National Plant Protection Organisation (NPPO) of that country, so the wood can be traced back to the treating facility.
- The treatment code — HT, DH, MB or SF.
An optional “DUN” designation may be added for loose dunnage rather than constructed packaging units — it does not change the treatment requirement, only the intended use of that particular piece of wood. The older “DB” (debarked) designation is no longer used on new marks, though wood marked under an earlier version of the standard remains acceptable on import — countries are expected to accept marks consistent with prior editions of ISPM 15.
Two formatting rules are easy to miss and both are explicit in the standard:
- The mark must not be hand-drawn. It must be applied by branding, stamping or stencilling — a handwritten mark is non-compliant regardless of what information it contains.
- Red or orange should be avoided as mark colours, because those colours are reserved for dangerous goods labelling and could cause confusion on the cargo transport unit.
It’s also worth correcting a common assumption directly: a unit of wood packaging carrying more than one ISPM 15 mark — for instance, from a prior repair — is not, by itself, evidence of non-compliance. The standard explicitly notes that the presence of multiple marks on a single unit does not constitute non-compliance, though it can complicate tracing the origin of a pest if one is later found.
ISPM 15 mark (“wheat stamp”) branded onto a pallet block. Photo: Rivermann, via Wikimedia Commons, licensed under CC BY-SA 4.0.
7. Import controls — where countries diverge from the base standard
ISPM 15 is a harmonising standard, not a single global law — each country’s NPPO implements it through its own national regulation, and that is where the practical variation sits:
- European Union — methyl bromide fumigation has not been permitted for any use, including QPS, since 2010, on environmental and health grounds. Wood packaging already treated and marked with MB before that date remains legally usable, but new MB-marked packaging manufactured for EU-bound shipments will not be accepted. Heat treatment and sulfuryl fluoride are the practical options for the EU market.
- United States — while MB remains listed under the standard, heat treatment is the accepted method in practice; APHIS oversight runs through the American Lumber Standards Committee (ALSC), which certifies both conventional heat treatment and MB facilities, but importers should confirm current acceptance before relying on MB-marked material.
- Australia — accepts ISPM 15-compliant timber packaging under its Biosecurity Import Conditions (BICON) system, but layers additional seasonal measures on top of the base standard — for example, mandatory treatment windows tied to the Brown Marmorated Stink Bug (BMSB) risk season, independent of whether the wood already carries a valid ISPM 15 mark.
- India — has adopted ISPM 15 nationally, and separately regulates methyl bromide fumigation of imported timber and wood/bamboo products under the Plant Quarantine (Regulation of Import into India) Order, 2003, which specifies its own dosage schedule (48 g/m³ for 24 hours at 21°C or above, or an approved equivalent) for un-ISPM-marked timber entering the country — a distinct, India-specific requirement that sits alongside, not instead of, the ISPM 15 mark on packaging.
Wooden pallet with treatment tag ID. Photo: Alain Van den Hende, via Wikimedia Commons, licensed under CC BY 4.0.
8. Validity, reuse, repair and remanufacture — how long does a treatment last?
There is no expiry date on an ISPM 15 mark. A unit of wood packaging material that has been treated and marked in accordance with the standard, and that has not since been repaired, remanufactured or otherwise altered, does not require re-treatment or re-marking for the rest of its service life — it can be reused indefinitely on that original mark. Validity is tied to the condition of the unit, not to a calendar period.
That validity breaks down once the unit is physically altered, and the standard draws a hard line based on how much of it is replaced:
- Repaired (up to roughly one-third of components removed and replaced): only wood that is itself ISPM 15-treated, or made from an exempted processed-wood material, may be used for the repair, and each added treated component must carry its own individual mark. The NPPO of the country where the repair takes place may, at its discretion, instead require the old marks to be obliterated and the whole unit re-treated and re-marked — and must require this wherever there is doubt that every component was properly treated, or the origin of the unit or its parts can’t be established.
- Remanufactured (more than roughly one-third of components replaced): this is treated as a new unit, full stop. Any previous marks must be permanently obliterated (painted over or ground off), and the unit must be re-treated and freshly marked in accordance with the standard before it can move again — this is mandatory, not a matter of NPPO discretion.
If methyl bromide is used for a repair-driven or remanufacture-driven re-treatment, the same environmental caution that applies to first-time MB treatment applies again — NPPOs are expected to have regard to the IPPC’s 2008 recommendation on replacing or reducing methyl bromide use.
9. Common errors that cause rejections
References
- International Plant Protection Convention (IPPC). ISPM 15. Regulation of wood packaging material in international trade. Rome: FAO, 2017 (core standard adopted 2009, CPM-4). https://www.ippc.int/static/media/files/publication/en/2017/02/ISPM_15_ED_En_2017-02-10.pdf
- International Plant Protection Convention (IPPC). ISPM 15 — Annex 1 and Annex 2, as revised by the Thirteenth Session of the Commission on Phytosanitary Measures (CPM-13, April 2018). Rome: FAO, published 2019. https://www.ippc.int/static/media/files/publication/en/2019/02/ISPM_15_2018_En_WoodPackaging_Post-CPM13_Rev_Annex1and2_Fixed_2019-02-01.pdf
- International Plant Protection Convention (IPPC). Countries — List of Contracting Parties, with links to each country’s NPPO contact point and phytosanitary requirements. https://www.ippc.int/en/countries/all/list-countries/
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