Some pallet wood is safe to burn, but not all of it. The difference comes down to how the wood was treated, what it was painted with, and what it carried during its working life. Burning the wrong pallet can release neurotoxic gases, heavy metals, or chemical fumes into your air. A quick check of the stamp on the wood tells you most of what you need to know.
How to Read the Stamp on a Pallet
Pallets shipped internationally are required to carry a stamp from the International Plant Protection Convention (IPPC). This stamp includes a treatment code that tells you exactly what was done to the wood before it entered the supply chain. Four codes are common:
- HT (Heat Treated): The wood was heated to kill parasites. Safe to burn.
- KD (Kiln Dried): A heat treatment that reduces moisture content. Safe to burn.
- DB (Debarked): The bark was stripped from the wood. Safe to burn.
- MB (Methyl Bromide): The wood was fumigated with a toxic chemical. Not safe to burn, handle, or use indoors.
The stamp is usually branded or printed onto one of the side boards (called stringers). If you can’t find a stamp at all, that pallet was likely used domestically and never treated, but the absence of a stamp also means you can’t verify what the wood has been exposed to. When in doubt, don’t burn it.
Why Methyl Bromide Pallets Are Dangerous
Methyl bromide is a potent neurotoxin. According to the Agency for Toxic Substances and Disease Registry, inhaling it can cause headache, nausea, dizziness, and visual disturbances within hours. At higher concentrations, it causes seizures, coma, lung inflammation, fluid buildup in the lungs, and kidney damage. Neurological and cognitive deficits from a single exposure can persist indefinitely.
Burning MB-stamped wood doesn’t neutralize the chemical. It releases it as a gas, often in an enclosed or semi-enclosed space like a fire pit, fireplace, or wood stove where you’re breathing close to the flames. Even skin contact with methyl bromide vapor at high concentrations can cause painful blistering similar to second-degree burns.
Methyl bromide treatment has been phased out in many countries, but it’s still used in parts of Asia and elsewhere. Pallets from China and India, for example, still carry MB-stamped wood into international shipping. If a pallet has traveled through global supply chains, checking for the MB code is essential.
Painted Pallets Are Off Limits
If a pallet is painted, don’t burn it. The most common colored pallets in the U.S. are blue (owned by CHEP) and red (owned by PECO), both belonging to large rental companies. These pallets use proprietary coatings, and the composition of those paints isn’t publicly disclosed in enough detail to confirm they’re safe for combustion. Penn State Extension recommends never burning any treated or painted pallet wood.
There’s also a legal issue. Painted pallets are almost always rental property. Using them for personal purposes, including firewood, is technically illegal since they’re supposed to be returned to their owners.
The Hidden Risk: What the Pallet Carried
Even a clean, HT-stamped pallet can be unsafe to burn if it absorbed chemicals during use. Wood is porous. Pallets spend their lives in warehouses, on loading docks, and in truck beds, often sitting under leaking containers or in pools of spilled fluids. Pesticides, solvents, cleaning agents, petroleum products, and countless other industrial chemicals can soak into the grain over time.
There’s no stamp or label that tracks what a pallet carried after it left the manufacturer. A pallet that looks perfectly clean might have absorbed chemicals that release toxic fumes when heated. This is the hardest risk to assess, and it’s the reason many safety experts are cautious about burning scavenged pallets even when the treatment code checks out. If you can trace the pallet’s origin to a food or beverage warehouse, the contamination risk drops significantly. If you found it behind an industrial facility, chemical plant, or auto shop, skip it.
Pressure-Treated Wood Is a Separate Problem
Pallets are not typically made from pressure-treated lumber, but it happens, and it’s worth knowing the difference. Older pressure-treated wood contains chromated copper arsenate (CCA), a preservative that includes arsenic. When CCA-treated wood is burned in an open fire, 11 to 14 percent of its total arsenic content is released into the air as vapor. The rest concentrates in the ash, which then contaminates soil and anything it touches.
Pressure-treated wood often has a greenish tint and feels slightly oily or waxy. If you see those characteristics on a pallet, it’s not standard pallet lumber, and you should not burn it under any circumstances.
How to Burn Pallet Wood Safely
If you’ve confirmed the pallet is stamped HT, DB, or KD, has no paint or stain, shows no greenish tint, and you’re reasonably confident it wasn’t exposed to chemical spills, it can work as firewood. A few practical notes will help you get the most out of it.
Pallet wood is typically softwood or low-density hardwood, cut thin. It burns fast and hot, which makes it excellent kindling or starter wood but a poor choice as your primary fuel for a long fire. Mixing pallet wood with denser hardwood logs gives you the quick ignition of the pallet pieces and the sustained heat of proper firewood.
Pull out all nails and staples before burning. Pallet fasteners are often spiral or ring-shank nails that won’t melt in a campfire or fireplace. They’ll end up in your ash, and stepping on one is an easy way to ruin your day. A pry bar and a claw hammer make quick work of disassembly.
Burn pallet wood in a well-ventilated area. Even clean wood produces carbon monoxide and particulate matter, and thin pallet boards can smolder and smoke more than seasoned cordwood. In a wood stove, keep the damper open until the pallet pieces are fully engaged. Outdoors, position yourself upwind.