Wooden pallets have long been in use in the United States, but one of the main weaknesses of wood is its perishability. Wood is a natural material, and as such, it tends to decompose unless it’s properly treated.
Organic material can also provide a haven for insects, bugs, bacteria, and other pests, making it a possible health hazard for those who handle products as well as the end customers. This is why wooden pallets should be properly treated prior to use in shipping and storage.
U.S. laws and regulations state that all pallets must be treated to prevent bugs and bacterial contamination before they can be shipped internationally. To comply with these regulations, pallets are treated in one of two ways: heat treated or chemically treated.
Heat treated pallets are heated to a core temperature of 56 degrees Celsius (or about 132 degrees Fahrenheit) for at least 30 minutes, whereas chemically treated pallets are fumigated with methyl bromide. The type of treatment used must be marked on all pallets.
There are two common types of treatment. Here are the advantages and drawbacks of each:
Chemical Treatment for Wooden Pallets
Chemical wood pallet treatments are made with methyl bromide (MB), a pesticide that has also been used in agricultural applications. The treatment is made by placing the pallets in an airtight chamber and sprayed with the chemical, which then soaks into the wood and kills anything living in its various pores and cracks. Methyl bromide is very effective at getting into porous surfaces and it has also been an economical pesticide in a variety of applications.
However, MB is also shown to be toxic. Not only does it kill pests, but it can be corrosive to human skin, making handling MB-treated pallets hazardous without the right equipment. Trace amounts may be less dangerous, and the chemical does tend to gas off from surfaces, but the porous nature of wood will often retain enough of the chemical to be a concern.
Also, since a certain concentration of the chemical is needed for it to be effective against pests, a well-treated pallet could be a hazard to humans. MB-treated pallets, therefore, have limited use, being reserved only for applications where contaminating food, agricultural products, or similar items won’t be possible.
Fortunately, there are standard procedures in place for handling MB-treated pallets and they must always be marked as treated, so if a pallet is potentially toxic you’ll be able to tell from the markings on its surface.
Heat Treatment for Wooden Pallets
Unlike chemical treatment, heat treatment can be done either before or after the wood has been debarked, thought it’s usually done after the pallet has been constructed.
Pallets are placed in a chamber that circulates hot air around the pallet with blower fans, getting it to high enough temperatures to eliminate any bacteria or pests in the material. The minimum time for heat treatment is 30 minutes, but it can last as long as 14 hours depending on the type of wood, its thickness, and so on.
Not only does this method rid the pallet of insects, bacteria, and other pests, it also serves to remove moisture from the wood as well. This keeps the material well preserved and keeps it from rotting. In addition, mold growth is prevented, making this method excellent when it comes to avoiding health hazards in the workplace.
The removal of moisture from the pallet also prevents warping and other forms of water damage to the pallet, not to mention temperature-related swelling or shrinking. This preserves the pallet and keeps it in good, usable shape for a long time.
Which Method is Better?
Both treatments effectively remove the presence of insects and bacteria. However the EPA recognizes methyl bromide as a highly toxic chemical and strongly discourages its use, especially when shipping food.
Scientific research also indicates methyl bromide is contributing to the break down of the Earth’s ozone layer. Given the risks associated with the chemical process, we believe heat treated pallets are a much safer option.
Also, in addition to being safer, heat treatment has added perks for the life and usability of pallets by preventing mold, rotting, and moisture damage. This means a better investment for you in the long run, both monetarily as well as in terms of health and safety.
By and large, wood pallets made in the U.S., Europe, and Canada are all heat treated, though it’s still possible to find methyl bromide treated pallets shipped out of other countries.
At Dominion Pallet, we only make and distribute heat treated pallets. Our pallets are stamped on both sides to easily clear customs and meet APHIS, ALSC, and IPPC guidelines, as well as European Union requirements.
Want to learn more about heat treated wooden pallets and the benefits they have for your industry? Contact us here.