Long before wood pallets became the material of choice for DIY furniture builders and as photo backgrounds for the Pinterest crowd, they were used pretty much exclusively in shipping and warehouses.
The reasons are numerous. Wood pallets are:
Even some of the knocks against wood pallets — they break and splinter, can be
But there is one more potential downside to using wood pallets which relates to the way the wood is treated. A little background is in order.
Even a little bit of moisture in an organic material like wood can become a breeding ground for mold, decomposition and rot. Heat treating wood draws out the moisture, making it less porous and less susceptible to mold and mildew. The process also hardens the wood and helps reduce swelling and shrinking that comes with temperature change.
If there’s moisture there’s life, and in this case, that means microorganisms that cause rot (decomposition) and insects. The havoc insects create is astonishing. They feed on wood crates, pallets and dunnage, and reproduce prolifically. And that’s just on the journey. Once here, they can infest and populate every location they encounter.
In the early 2000s, the International Plant Protection Convention (IPPC) introduced a regulation, ISPM 15, to attempt to reduce the introduction and spread of wood-boring insects. The regulation laid out guidelines for treating wood pallets, there are only two — heat treatment (HT) and methyl bromide (MB) treatment. The ISPM 15 states that whichever treatment is used, the pallet or packing material must be made of debarked wood (DB), since moisture and insects are found in bark. MB treatment is done after tree bark is removed; debarking can be done before or after heat treatment
Pallets are placed in a large heating chamber until it reaches a core temperature of 132 degrees Fahrenheit for a minimum of 30 continuous minutes. The process varies in length of time based on the thickness and type of wood (soft wood or hard wood) but can last between 5 to 14 hours. Blowers circulate the hot air around the pallets.
Pallets are stacked in a sealed chamber and sprayed with the chemical methyl bromide. The chemical soaks into the wood and then dries. Wood pallets made in the US, Canada and Europe are not MB treated, and the chemical is being phased out completely. However, it’s still possible to find pallets that have been MB treated.
Methyl bromide is a powerful chemical fumigant that is very effective in killing pests. Unfortunately, it has been proven to adversely affect the ozone layer. It is also highly toxic to humans and is corrosive to both skin and eyes. Handling wood pallets, crates or dunnage that have been treated with MB without protective gear is dangerous.
The ISPM 15 regulation is considered best practices in lumber use and handling. The Pacific Lumber Inspection Bureau (PLIB) maintains a current list of countries that have adopted the regulation. The PLIB site is filled with useful information and FAQs about wood packaging and the regulations surrounding the product.
After the pallets are treated they are stamped with a certification mark.
There are a variety of codes that are used on wood pallets (click on chart above for pdf version). Look for these codes to know whether a wood pallet is safe to use. Always remember to verify the origin of your pallet, even if it is stamped with a safe-to-use code.
After reading about the dangers and regulations associated with using wood pallets you might be thinking hard about using some other pallet material, like plastic. Not so fast. There are pros and cons to everything. Fortunately pallet provider, Olympic, created this handy comparison of wood versus plastic pallets.
Whether you use wood or plastic pallets will depend on a host of variables — your product, the cost, your shipper or your personal preference. Your account manager is the best first point of contact in order to get an accurate quote.
To learn more about shipping processes, check out these previous posts: