As border controls tighten and environmental controls increase in supply chains, one area of compliance continues to pose problems for experienced exporters: wood packaging.
While commercial documentation often receives the most attention during shipment preparation, the physical packaging itself – pallets, crates and dunnage – is often the trigger for border inspection stops. If solid wood packaging is not ISPM 15 compliant, it is not just a compliance query. This can lead to delays, rework and avoidable operational costs that no amount of correct paperwork can resolve.
Pallet2Ship, a UK-based pallet shipping platform that has worked with thousands of exporters since 2009, says the problem is rarely that companies don’t know the rules exist. It happens that the practical benefits are missed in everyday warehouse operations.
“In daily operations, solid wood packaging is one of the most common inspection triggers,” says a Pallet2Ship spokesperson. “Compliance occurs at the point where your packaging decisions, carrier handover, and border clearance all come together. If any of these three points fail, your shipment may be sitting in depot while markings are checked or packaging is reworked.”
The biosecurity risks of wooden packaging
ISPM 15 (International Standard for Phytosanitary Measures No. 15), developed under the International Plant Protection Convention, exists for one simple reason: to prevent the cross-border spread of invasive pests in untreated wood.
All solid wood packaging used in international trade with a thickness of more than 6mm must be heat treated or treated with an approved alternative method and must bear an official IPPC mark identifying the treatment provider, country code and treatment type.
On paper it’s simple. In practice, mistakes happen at the margins – and that happens often.
The Treatment Switch: From Methyl Bromide to Heat
One of the biggest changes in recent years has been the move away from methyl bromide fumigation.
MB was widely used for decades but is now severely restricted worldwide due to its impact on the environment. The industry has shifted to cleaner and more sustainable treatment methods:
Heat treatment (HT) – Wood is heated to a core temperature of 56°C for at least 30 minutes. This is now the standard method and accounts for the vast majority of compliant pallets in circulation.
Dielectric heating (DH) – microwave or radiofrequency treatment, less common but recognized within authorized systems.
Sulfuryl Fluoride (SF) – A fumigation alternative used in certain regulated contexts, primarily for quarantine or pre-shipment situations.
For most exporters, heat treated pallets stamped “HT” on the IPPC mark are the practical standard. It is reliable, widely accepted and avoids much of the environmental impact associated with older fumigation methods.
Post-Brexit confusion: what actually applies where
This is where many British exporters still stumble.
ISPM 15 applies to solid wood packaging shipped between the UK and the European Union. This also applies to deliveries from Great Britain to Northern Ireland as Northern Ireland follows European Union phytosanitary regulations under the Windsor Framework.
The requirement does not apply to shipments from Northern Ireland to Great Britain and wooden packaging transported from Northern Ireland to the European Union is treated as intra-European Union trade, so ISPM 15 is not required on this route.
Many exporters assume that ISPM 15 is not applicable because some movements feel “domestic” in practice. This assumption is incorrect and can cause problems at consolidation centers or during carrier inspections.
Another mistake is to assume that compliance is optional, as some road freight shipments to the European Union appear to proceed without inspection. While the intensity of enforcement varies – depending on route, carrier, type of goods and checkpoint – the underlying requirement does not change.
Enforcement is stricter for higher-risk destinations such as Australia, New Zealand and the United States. Violations on these lanes more often result in delays, rework and, in some cases, rejection or destruction of packaging.
Common operational failure points
Pallet2Ship’s detailed compliance guide identifies these as the four key failure points that exporters should control:
The 6MM misunderstanding
ISPM 15 applies to solid wood components with a thickness of more than 6 mm. Thinner wood is generally exempt – but standard pallets, boxes and wooden struts are almost always well above this limit. The exception applies to thin support boards or battens, not to pallets themselves.
The repair trap
A pallet can start life completely compliant, stamped and treated correctly. Then someone in the camp repairs a broken board with a piece of untreated wood. The original stamp is still present, but the palette is now non-compliant. Ad hoc repairs involving unknown wood immediately void compliance.
Visibility of the stamp
IPPC markings must be visible on at least two opposite sides of the pallet. Wrapping the pallet tightly and covering the stamps with stretch wrap or placing shipping labels over them will prevent an inspector from verifying compliance. If they can’t see it, they often assume it’s missing.
Last minute stowage
Everything is properly packed on a compliant pallet. Then, at the last moment, someone adds a scrap of wood to prevent anything from shifting during transport. This piece of wood is now part of the packaging, and if it is not ISPM 15 compliant, the entire shipment can be flagged.
Most of these problems are not intentional. This happens because decisions are made quickly in the warehouse, often by people focused on delivering the shipment rather than reviewing compliance details.
Exceptions and alternatives
There are alternatives for companies that want to reduce the overall compliance burden associated with wood.
Processed wood products such as plywood, OSB, MDF and particle board are generally exempt from ISPM 15 because the high heat processes associated with their production destroy pests. Pressed wood or wood fiber pallets fall into the same category of processed wood and are also outside the scope of ISPM 15.
Plastic and metal pallets also do not fall within the scope of the standard because they are not made of raw solid wood.
For some trade routes, switching to these materials can simplify border control compliance while meeting viability and sustainability requirements.
The trade-off is usually cost. Processed wood and plastic pallets are typically more expensive upfront than standard heat-treated wood pallets. Therefore, the decision depends on the shipment volume, the destination risk and whether the costs of possible delays outweigh the costs of changing materials.
A practical ISPM 15 compliance framework for exporters
Pallet2Ship has published a detailed ISPM 15 pallet compliance guide that breaks down the controls exporters should build into daily operations. The ten-point checklist covers everything from supplier verification to photo evidence before shipping.
The core advice is simple:
- Separate export pallets from domestic pallets in the warehouse. Don’t let them mix.
- Check the stamps before packing. Make sure the IPPC mark is legible on two facing sides and contains a valid country code, facility code and treatment code, usually HT.
- Check all wood additives. Any dunnage, bracing or blocking added during packaging must also be ISPM 15 compliant.
- Take photos before pickup. A quick snapshot of the pallet from multiple angles provides proof of compliance if a question arises later.
- Use new pallets for high risk routes. Reused pallets can be compliant, but faded spots, hidden repairs and contamination are more common. For Australia, New Zealand, the United States or time-sensitive, high-value shipments, new heat-treated inventory eliminates uncertainty.
None of this is complicated, but it does require discipline. The best time to detect an ISPM 15 problem is before the vehicle leaves your loading dock. Once it’s collected, your options will be significantly limited.
Build compliance into operations rather than fixing it later
ISPM 15 compliance is not paperwork that you can do after the fact. It is a storage discipline that must be integrated into daily packing routines.
By treating pallet compliance as part of standard operating controls rather than something to be addressed post-collection, disruptions are reduced, margins are protected and cross-border shipments continue to flow smoothly.
For companies moving goods internationally, it’s not about checking a regulatory box. It’s about avoiding avoidable delays that cost time, money and customer trust.
Pallet2Ship’s complete ISPM 15 compliance guide, including the handy ten-point export checklist, is available on the Pallet2Ship website.
