Every crackling fire tells a story—but not all of them are safe to burn. Residential wood burning often contributes more toxic air pollution than vehicle traffic, and many common woods release harmful chemicals when burned. From respiratory issues to cancer-causing toxins, the wrong firewood can turn cozy moments into health hazards.
Protect yourself, your family, and the environment by avoiding these 15 woods. Here’s what you should never throw in your fireplace or fire pit.
1. Driftwood
Ocean driftwood contains high levels of absorbed salt that releases toxic chlorine gas and carcinogenic dioxins when burned. (ref) These chemicals can cause severe respiratory issues and have been linked to various forms of cancer.
The deceptively beautiful colors produced when burning driftwood are actually visible signs of these dangerous compounds being released into the air. Even freshwater driftwood should be avoided as it likely contains absorbed pollutants and chemicals from its time in the water.
2. Pressure-Treated Wood
Pressure-treated lumber contains powerful chemical preservatives that become extremely toxic when burned. These woods are typically treated with compounds designed to prevent decay and pest infestation, but when combusted, they release dangerous fumes that can be immediately harmful.
The preservative chemicals used in pressure-treated wood can include arsenic compounds, which become airborne during burning and pose serious health risks. Never burn construction materials, fence posts, or any wood that appears to have been chemically treated.
3. Green or Unseasoned Wood
Freshly cut “green” wood contains excessive moisture that creates thick smoke and dangerous creosote buildup in chimneys. This wet wood burns inefficiently and produces significantly more harmful particulate matter than properly seasoned wood.
The high moisture content in green wood not only creates a poor burning experience but can lead to dangerous chimney fires due to creosote accumulation. Wood needs to be properly dried for at least 6-12 months before burning to ensure safe and efficient combustion.
4. Painted or Varnished Wood
Burning painted or varnished wood releases toxic chemicals from the finishes into the air. These can include heavy metals, synthetic chemicals, and other harmful compounds that become airborne when burned.
Old furniture pieces or decorative woods often contain multiple layers of paint or finish that create particularly dangerous fumes when combusted. The toxins released can cause immediate respiratory issues and potentially long-term health problems.
5. Moldy or Rotten Wood
Moldy wood releases dangerous spores and mycotoxins into the air when burned. These airborne pollutants can cause severe respiratory issues and trigger allergic reactions in sensitive individuals.
Rotten wood also burns inefficiently due to its compromised cellular structure and typically higher moisture content. The decomposition process changes the wood’s density, making it produce less heat and more smoke when burned.
6. Plywood & Engineered Woods
These manufactured woods contain powerful adhesives and resins that release toxic fumes when burned. The bonding agents used in their construction often contain formaldehyde and other harmful chemicals.
When exposed to high temperatures, these synthetic materials break down into dangerous compounds that can cause immediate health effects like headaches, nausea, and respiratory distress. The chemicals released can be particularly harmful to children and elderly individuals.
7. Pine & Resinous Softwoods
Pine and other softwoods contain high levels of resin that create excessive creosote buildup in chimneys. (ref) This sticky substance can accumulate quickly and significantly increase the risk of dangerous chimney fires.
While these woods might seem like a convenient option, their fast-burning nature and high sap content make them unsuitable for indoor burning. The thick smoke they produce contains higher levels of particulate matter that can irritate the lungs and airways.
8. Poison Woods
Woods from toxic species like poison oak, poison ivy, and oleander release irritant oils in their smoke that can cause severe respiratory problems. These naturally toxic plants remain dangerous even when burned, as their harmful compounds become airborne.
The smoke from these species can cause serious breathing difficulties and eye irritation, with some cases requiring hospitalization. Even small amounts of these woods mixed into a fire can create dangerous conditions.
9. Laburnum
This ornamental tree produces highly toxic smoke when burned. The wood contains dangerous alkaloids that become airborne during combustion and can cause serious respiratory issues.
The fumes from burning laburnum can linger in enclosed spaces and cause lung damage over time. Despite its attractive appearance, this wood should never be used as firewood due to its toxic properties.
10. Elder Wood
Elder burns quickly without producing much heat and creates thick, acrid smoke. The wood’s particular chemical composition results in an unpleasant burning experience and potentially harmful emissions.
The smoke produced by elder wood has a notably unpleasant odor and can irritate airways and eyes. Its poor burning qualities and potential health risks make it an unsuitable choice for any type of fire.
11. Treated Pallet Wood
Many wooden pallets are treated with chemicals to prevent decay and pest infestation. These treatments can include methyl bromide and other toxic substances that become dangerous when burned.
Unless you can verify that a pallet is chemical-free and made from untreated wood, it should never be used as firewood. The risk of releasing harmful chemicals into the air is too high to justify burning these materials.
12. Rhododendron
Rhododendron wood contains toxins that can be released into the air when burned. (ref) The smoke from this ornamental plant can be particularly harmful to both humans and animals.
When burned, rhododendrons release compounds that can cause respiratory distress and other health issues. Its toxic nature makes it unsuitable for any type of burning, despite its availability in many gardens.
13. Poplar
Poplar wood produces thick, black smoke and doesn’t ignite easily. Its burning characteristics create excessive pollution and provide very little heat output.
The acrid smoke produced by poplar can be particularly irritating to the respiratory system. The wood’s poor burning qualities and smoke production make it an inefficient and potentially harmful choice for fires.
14. Construction Debris
Construction wood waste often contains a mixture of treated materials, adhesives, and unknown contaminants. These materials can release a cocktail of toxic substances when burned.
The variety of chemicals present in construction debris makes it impossible to predict what harmful compounds might be released during burning. The risk of exposure to dangerous fumes is particularly high with these materials.
15. Willow
Willow wood burns with excessive smoke production and provides minimal heat output. Its burning characteristics make it particularly unsuitable for indoor fires.
The wood’s tendency to create large amounts of smoke can lead to dangerous levels of indoor air pollution. The poor heat output and high smoke production make willow an inefficient and potentially harmful choice for burning.
When it comes to burning wood safely, knowledge is your best protection. Always source your firewood from reputable suppliers who can verify the wood type and confirm it’s properly seasoned.
Source:
Don’t Miss These:
Hummingbirds Aren’t Just After Nectar—Here’s What They Need
15 Survival Myths That Could Cost You Your Life
Say Goodbye to Leaf Scorch with These 10 Plant Care Tips
17 Plants That Add Beauty & Amazing Scents to Your Yard
DIY Mole Control: Does Dawn Dish Soap Really Work?
Sourdough Starter Basics: Steps to Kickstart Your Bread Journey
15 Ways to Repurpose Supplement & Pill Bottles for Everyday Use
Transform Your Shower Routine with DIY Aromatherapy Steamers
Davin is a jack-of-all-trades but has professional training and experience in various home and garden subjects. He leans on other experts when needed and edits and fact-checks all articles.