Before you fire up the fireplace, learn which woods to avoid
There’s nothing better than cozying up to a roaring fire on a blustery day. (Okay, a campfire with s’mores comes pretty close!). But not all woods are safe to burn, so you’ll want to know what to avoid before you light your next fire.
Learn which woods are toxic to burn for your next fireside get-together—and get recommendations for safer firewood too.
1. Green Wood
Green wood is the term used for wood that has recently been cut down. Freshly cut wood still contains a significant amount of moisture, so it is one of the worst choices for burning.
Not only does all the moisture make it harder to burn (and causes a lot of smoke), but burning this kind of wood can also cause creosote to form on the inside of your chimney flues. All it takes is 1/8 inch of creosote buildup to cause a chimney fire.
Creosote is one of the leading causes of chimney fires, which is why it’s important to hire a local chimney cleaning company before lighting your next fire if you’ve used green wood in the past. However, you can burn green wood if it’s been “seasoned” or dried.
Wood that has less than 20% moisture and has been kiln dried is best for burning. While air-drying is another, more natural, and less expensive method, kiln-drying wood is faster and results in a more consistent and efficient burn.
Softwoods, such as firs, redwoods, and pines, are loaded with resin. Resin is a sticky, sap-like substance that hardens when exposed to the air and can eventually fossilize into amber.
As a result, when you burn these woods, you’ll have darker, thicker smoke that carries even more creosote that can collect in your chimney flues and cause a fire.
And breathing in this thicker smoke can come with toxic consequences, such as exposure to particle pollution, carbon monoxide, and nitrogen oxides. This can cause a burning throat, coughing, itchy eyes, and trouble breathing.
3. Mexican Elder Tree
The Mexican elder is a type of tree (softwood) that actually contains a natural form of cyanide, which is a poison that can prevent the cells in your body from absorbing oxygen, and as a result, cells begin to die. This can be extremely dangerous for your heart and brain, as these two organs need the most oxygen.
When you burn the toxic wood from this tree, the smoke contains cyanide and when breathed, could cause cyanide poisoning.
It may be tempting to pick up some driftwood for a beachside fire, but burning driftwood is even more toxic than other types.
When you burn wood, it releases a carcinogen called dioxin. And when you burn driftwood, the salt transforms into chlorine and mixes with the dioxin, causing a dangerous combination that some believe is connected to certain types of cancer.
5. Plywood, Stained Wood, and Other Treated Wood
Any wood that has been treated with chemicals, such as formaldehyde and alkaline copper quaternary, is likely toxic when burned.
For example, plywood is several thin pieces of wood that have been glued together with formaldehyde. So when you burn plywood, you’re also burning the glue and formaldehyde, which can cause severe allergic reactions, such as burning in the eyes and throat, skin rash, wheezing, and difficulty breathing.
6. Rotten Wood
Rotten wood is harder to burn and doesn't produce as much heat, but you are potentially putting yourself in harm's way if you can start a fire with it.
Rotten wood often contains mold, so mold travels from the wood to your lungs when you burn it. And since rotten wood has more moisture, it will produce more smoke.
7. Wood Pallets
Typically, wood pallets are not toxic to burn unless treated with chemicals. The most common chemicals include arsenic or methyl bromide to help pallets withstand pests and weather when kept outside.
Methyl bromide has been linked to issues with the lungs, eyes, and skin and harms the ozone layer. If you’re not 100% sure that the pallets are chemical-free, do not burn them.
Safer Firewood Options
First, even when not considered toxic, burning any wood can expose you to air pollutants, such as benzene and formaldehyde, that can affect your health. But some are considered safer than the ones listed above.
The types of woods generally considered safe to burn include hardwoods like oak, cedar, elm, birch, and ash.
The general rule is to burn the driest wood available and make sure it’s from your local area. Untreated traveling firewood can actually carry insects, such as tree-killing beetles and caterpillars, that can wreak havoc to a new location.