If your business ships products internationally using wood pallets, crates, or dunnage, you need to understand ISPM 15. The International Standards for Phytosanitary Measures No. 15 is a set of guidelines developed by the International Plant Protection Convention that governs the treatment of wood packaging materials used in international trade. Non-compliance can result in shipment rejection at the border, costly fumigation, quarantine fees, and significant delays that disrupt your supply chain.
Despite being in effect since 2002, ISPM 15 remains one of the most frequently misunderstood regulations in international logistics. In this article we break down exactly what the standard requires, how the heat treatment process works, how to identify compliant pallets, and what happens when you get it wrong.
Why ISPM 15 Exists
ISPM 15 was created to prevent the international spread of invasive insects and plant diseases through wood packaging materials. Before the standard was implemented, untreated wood pallets and crates were a primary vector for the transmission of destructive pests including the Asian longhorned beetle, the pine wood nematode, and the emerald ash borer. These organisms can devastate forest ecosystems in regions where they are not native, causing billions of dollars in ecological and economic damage.
The Asian longhorned beetle alone has caused an estimated 669 billion dollars in potential damage to North American forests. The emerald ash borer has killed hundreds of millions of ash trees across the eastern United States. ISPM 15 was the international community response to these threats, establishing a baseline treatment standard that all wood packaging must meet before crossing international borders.
What ISPM 15 Requires
The standard requires that all wood packaging materials, including pallets, crates, dunnage, and blocking, used in international trade must be treated using one of two approved methods. The most common method is heat treatment, designated by the code HT. The alternative is methyl bromide fumigation, designated MB, though this method is being phased out in many countries due to its ozone-depleting properties.
Heat Treatment Specifications
Heat treatment requires that the core temperature of the wood reach a minimum of 56 degrees Celsius (132.8 degrees Fahrenheit) for a minimum of 30 continuous minutes. This temperature and duration combination is sufficient to kill all regulated pests and pathogens that could be present in the wood. The treatment must be performed in a certified kiln or heat treatment chamber that is regularly calibrated and inspected.
The ISPM 15 Stamp
Treated pallets must bear a specific mark that includes the IPPC logo (a wheat stalk symbol), a two-letter country code, a unique producer or treatment facility number, and the treatment code HT or MB. This stamp is your proof of compliance and must be clearly visible on at least two opposite sides of the pallet. Customs inspectors look for this stamp, and its absence or illegibility can trigger rejection.
The Heat Treatment Process Step by Step
- 1Raw lumber or assembled pallets are loaded into a certified heat treatment chamber or kiln
- 2Temperature probes are inserted into the core of representative wood pieces to monitor internal temperature
- 3The chamber is heated until core temperature reaches 56 degrees Celsius across all monitored points
- 4The 56-degree temperature is maintained for a minimum of 30 continuous minutes with documentation
- 5The chamber is cooled and pallets are removed and inspected
- 6The official ISPM 15 stamp is applied to each treated pallet using a branding iron or ink stamp
- 7Treatment records are filed and retained for a minimum period as required by the national plant protection organization
Which Countries Enforce ISPM 15
As of 2025, ISPM 15 is enforced by virtually every country that participates in international trade. The standard has been adopted by all 27 European Union member states, the United States, Canada, Mexico, China, Japan, South Korea, Australia, New Zealand, Brazil, and over 180 additional countries. There are effectively no major trading partners that do not require ISPM 15 compliance for wood packaging materials.
Enforcement rigor varies by country. The European Union, Australia, New Zealand, and China are known for particularly strict inspection and enforcement. The United States requires compliance on all incoming wood packaging but enforcement at ports of entry can be inconsistent. Regardless of enforcement rigor, compliance is always required and non-compliance always carries risk.
What Happens If You Ship Non-Compliant Pallets
- Shipment may be held at the port of entry pending inspection, incurring storage and demurrage charges
- Pallets may be confiscated and destroyed at the shippers expense
- The entire shipment may be ordered for fumigation treatment at the destination, costing thousands of dollars
- In severe cases, the shipment may be refused entry and returned to the country of origin at the shippers expense
- Repeat violations can result in enhanced inspection scrutiny on all future shipments from your company
- Your customer relationship may be damaged by delivery delays caused by non-compliance
Exemptions from ISPM 15
Not all wood packaging requires treatment. Processed wood products such as plywood, particle board, oriented strand board, and veneer are exempt because the manufacturing process involves heat and pressure sufficient to eliminate pests. Plastic pallets, metal pallets, and paper-based packaging are also exempt. Wood packaging material that is 6 mm thick or less is exempt, as is wood that has been sufficiently processed to be free of pests.
How Pallets Eco Ensures Compliance
All heat-treated pallets from Pallets Eco are processed in our certified treatment facility and stamped with the official ISPM 15 mark. We maintain complete treatment records and our facility is regularly audited by USDA APHIS. When you order heat-treated pallets from us, you can be confident that every unit meets the standard and will clear customs without issues. We also offer ISPM 15 compliance consultation to help you audit your existing pallet supply for compliance gaps. Contact us to learn more about our heat-treated pallet inventory and export-ready packaging solutions.