What is ISPM 15? Requirements, treatments, marking, and scope

Purpose and scope

International Standards for Phytosanitary Measures No. 15 (ISPM 15) aims to reduce the risk of introducing and spreading quarantine pests via wood packaging material (WPM) used in international trade. The standard applies to non-manufactured wood packaging such as pallets, crates, boxes, drums, cases, dunnage, and other timber packing components. It does not usually apply to wood that has been manufactured into products such as plywood, particleboard, oriented strand board, or veneer that has been glued or processed — these products are typically considered low risk.

Key requirements

At its core, ISPM 15 requires that regulated WPM be subjected to an approved phytosanitary treatment and be permanently marked to demonstrate compliance. The main elements are:

• Treatment: Wood must undergo an NPPO-authorized treatment to eliminate pests. Commonly accepted treatments are heat treatment and methyl bromide fumigation. Other treatments may be accepted if approved by the NPPO.

• Marking: WPM must bear a durable, legible, and permanent mark showing the IPPC symbol, the country code, a unique producer or treatment provider code, and a treatment code indicating the method applied.

• Traceability and authorization: Treatment providers and facilities must be authorized by the national plant protection organization and maintain records for verification and audits.

Approved treatments

The two widely recognized treatment methods under ISPM 15 are:

• Heat treatment (HT): The wood must reach a minimum wood core temperature of 56 degrees Celsius and maintain that temperature for at least 30 minutes. This is commonly referred to as HT 56/30.

• Methyl bromide fumigation (MB): Fumigation with methyl bromide under specified concentrations and exposure times. Because methyl bromide is an ozone-depleting substance, its use is subject to international phase-downs and many countries are reducing reliance on this method in favor of heat or other alternatives.

Other phytosanitary measures or emerging technologies may be authorized by NPPOs when they provide equivalent phytosanitary efficacy and are documented.

Marking format and information

The ISPM 15 mark is standardized and includes the following components: the IPPC symbol, an ISO country code, a producer or treatment provider code assigned by the NPPO, and a treatment code such as HT for heat treatment or MB for methyl bromide. The mark should be applied in a way that is permanent and legible, typically stamped or branded on two opposite sides of the item. Example format (no quotes): IPPC symbol COUNTRY-XXX HT. A properly applied mark serves as the first-line verification for inspectors.

Exemptions and special cases

ISPM 15 generally does not apply to wood packaging made entirely from processed wood products such as plywood, particleboard, veneer, and other composite products. Very thin wood under a minimum thickness (commonly less than 6 mm) may be excluded in certain jurisdictions. Additionally, wood packaging used in purely domestic transport is outside the scope of ISPM 15; however, many countries choose to apply similar requirements domestically to reduce internal pest spread. NPPOs may also publish lists of exemptions or specific rules for reused, repaired, or reconditioned WPM.

Implementation and verification

Implementation occurs through national regulations enforced by NPPOs and customs agencies. NPPOs authorize treatment facilities, assign producer codes, and audit compliance. Inspectors at ports of entry check for valid ISPM 15 marks and may require corrective measures such as re-treatment, isolation, re-export, or destruction for non-compliant WPM. Proper documentation, treatment logs, and clear marking reduce the risk of detention and associated costs.

Practical examples

Common examples of compliant WPM include heat-treated pallets stamped with the ISPM 15 mark and export crates treated and stamped by authorized facilities. A non-compliant example would be a wooden crate lacking a legible ISPM 15 stamp or showing an outdated or incorrect treatment code. Repairs that remove or obscure the ISPM 15 stamp can also invalidate compliance unless the piece is re-treated and re-marked under NPPO guidance.

Benefits and limitations

ISPM 15 has helped harmonize phytosanitary procedures, reducing the incidence of pest introductions associated with WPM and facilitating trade through consistent expectations. Limitations include implementation variability across countries, the logistical and cost impact of treatment and marking processes, and reliance on treatments such as methyl bromide that are being phased down for environmental reasons. Continued innovation in treatment technologies, improved traceability, and consistent NPPO enforcement are key to addressing these limitations.

Best practices

For exporters and manufacturers: ensure treatment is completed prior to shipment, apply the ISPM 15 mark correctly and durably, keep treatment and authorization records, and monitor repairs and re-use of pallets. For NPPOs: maintain updated lists of authorized providers, communicate implementation rules clearly, and coordinate with customs to streamline inspections.

Conclusion

ISPM 15 defines a compact but critical set of requirements—approved treatments, persistent marking, and NPPO oversight—designed to reduce pest movements on wood packaging in international trade. Its proper application protects agriculture and forests while supporting predictable global commerce.