Untreated wood poses a significant risk of introducing plant pests, including pathogens, that can be detrimental to agriculture and to natural, cultivated, and urban forest resources. U.S. Department of Agriculture regulations contain provisions to mitigate plant pest risk presented by the importation of such wood. Because the packaging materials are very often reused, the true origin of any piece of Wood Packaging Material (WPM) is difficult to determine and, thus, its treatment status cannot be ascertained. Therefore, the USDA amended its regulations by adopting the international standard for WPM approved by the Interim Commission on Phytosanitary Measures of the International Plant Protection Convention (IPPC) on March 15, 2002. By adopting the IPPC guidelines, the U.S. harmonized its trade requirements with a host of other countries.
Most wood packaging materials are covered by the rule, including wooden packaging materials such as pallets, crates, boxes, and pieces of wood used to support or brace cargo. Wood packaging material is defined as wood or wood products (excluding paper products) used for supporting, protecting, or carrying cargo, including, but not limited to, dunnage, crating, pallets, packing blocks, drums, cases, or skids. The definition excludes manufactured wood materials, loose wood packing materials, and wood pieces less than 6mm thick in any dimension.
There are two treatment options: heat treatment or fumigation with methyl bromide. For heat treatment, WPM must be heat treated to achieve a minimum wood core temperature of 56°C for a minimum of 30 minutes. For fumigation, the WPM must be fumigated with methyl bromide in an enclosed area for at least 16 hours at the regulated dosage and then must be aerated to reduce the concentration of fumigant below hazardous exposure levels. After either of these treatments, the WPM must be marked in a visible location on each article, preferably on at least two opposite sides of the article, with a legible and permanent mark, approved by the IPPC, to certify that wood packaging material has been subjected to an approved treatment.
Marks will vary by country and treatment establishment. The mark must include the IPPC trademarked graphic symbol, the ISO two-letter country code for the country that produced the wood packaging material, a unique number assigned by the national plant protection agency of that country to the producer of the wood packaging material, and an abbreviation disclosing the type of treatment.