Heat treatment, ISPM-15, and the HT stamp.

ISPM-15 (International Standards for Phytosanitary Measures No. 15) is a global rule that regulates solid wood packaging material — pallets, crates, dunnage, and blocking — moving in international trade. Its purpose is to stop timber pests and wood-boring insects from hitchhiking across borders inside packaging. To comply, wood must be treated by an approved method and bear the official IPPC stamp certifying that treatment.

Crucially, the rule applies only to cross-bordershipments. If your pallet never leaves the country, ISPM-15 doesn't apply — a standard recycled 48×40 GMA is perfectly legal for domestic freight without any stamp.

ISPM-15 recognizes a few treatment codes. The two you'll see most are HT (heat treatment) and the fading MB (methyl bromide fumigation). Heat treatment has become the default because methyl bromide is an ozone-depleting substance being phased out globally.

Heat treatment fits our low-impact, circular ethos — no fumigants, just controlled heat that also lets the same timber be reused and re-stamped down the line.

A compliant pallet carries the IPPC “wheat stalk” logo inside a bordered mark, along with a set of codes. Here's how to decode it. For a fuller field guide, see reading a pallet stamp.

No stamp, or a stamp missing the treatment code, means the pallet is not certified for export — regardless of how it was actually made. A painted or heavily damaged stamp can also be rejected at the border, so inspect it before shipping.

The short version: staying domestic? Any sound recycled pallet works. Crossing a border with solid-wood packaging? You need HT. When you're unsure, tell us the destination and we'll spec it — including a compliant footprint from our new & custom builds.

Heat treatment is not just “putting wood in an oven.” It is a controlled, documented process that has to drive the core of the thickest board — not just the surface — to at least 56°C (133°F) for a minimum of 30 continuous minutes. Getting the surface hot is easy; proving the core reached temperature is what certification is about. Here is the sequence a certified facility follows.

Note that heat treatment targets pests, not moisture. A pallet can be bone-dry and still fail ISPM-15 if the process was never documented, and a properly HT-treated pallet is not necessarily kiln-dried. The two goals are related but not the same.

Pallet abbreviations get conflated constantly. Only some of them are phytosanitary treatments that satisfy ISPM-15; others describe the wood's condition and have nothing to do with export compliance. This table sorts them out.

The trap is KD: kiln drying alone does not make a pallet export-legal. Only HT, DH, or MB inside a proper IPPC stamp certify compliance. Heat treatment fits our low-impact, circular ethos — no fumigants, and the same timber can be reused and re-stamped down the line.

A compliant pallet carries the IPPC “wheat stalk” logo inside a bordered mark alongside a set of codes. Reading it left to right and top to bottom tells you where the wood was treated, by whom, and how. For a fuller field guide see reading a pallet stamp.

No stamp, or a stamp missing the treatment code, means the pallet is not certified for export — regardless of how it was actually made. A painted-over, illegible, or heavily damaged stamp can also be rejected at the border, so inspect it before shipping.

ISPM-15 has been adopted by the large majority of trading nations, so the safe assumption for any overseas solid-wood packaging is that it applies. The requirement rides on the packaging material, not the product inside — so even a shipment of metal parts on a wooden pallet needs the stamp.

Most sizing mistakes on export orders are really compliance mistakes. Walk this short path before you buy, and you will know whether a standard recycled pallet will clear or whether you need a stamped, treated unit.

The short version: staying domestic means any sound recycled pallet works. Crossing a border with solid-wood packaging means you need HT. When unsure, tell us the destination and we will spec compliant units and the right footprint from our new & custom builds.

The stamp certifies the treatment, but keeping a shipment compliant is an ongoing responsibility — a perfectly treated pallet can still be rejected if it is later contaminated or damaged. Here are the pitfalls that trip up exporters.

Because a repair with fresh, untreated wood invalidates the stamp, export pallets should be repaired only with treated lumber and re-marked. If you are unsure whether your stock still qualifies, ask us and we will check it against these criteria.