Can You Burn Pressure Treated Wood?

Last Updated on June 15, 2023 by Grow with Bovees

Today we will be answering the question, “can you burn pressure treated wood”, and looking at some factors that need to be taken into consideration when burning pressure treated wood.

We will be exploring what constitutes pressure treated wood and how to use it and dispose of it safely and efficiently.

As well as discussing possible environmental risks and health hazards.

What Is Pressure Treated Wood?

Processed wood known as pressure treated wood is wood that has been mixed with certain chemicals that shield the wood from decay, infestation by wood eating critters, or even against mold and water absorption.

The process of treating this wood also makes it more durable and strong. There are many different types of processed wood, each with different applications.

For instance, some pressure treated woods are designed to be flame retardant.  

Is My Wood Pressure Treated or Not?

Often enough, this type of wood will have stamps or tags on it, showing the chemical constitution of the treatment process.

The smell might also be a good indicator, if it smells oily or in any way different to what a normal piece of wood smells like, be aware.

There may also be identifiable discoloration on the wood surface, usually green or blueIs the wood safe to burn? When in doubt, don’t burn it. 

Below is a guideline you can use to distinguish between different types of pressure treated wood:

CCA wood -(Chromated Copper Arsenate – Green

If there is a recognizable greenish hue on the wood, it has probably been treated with arsenic-containing chromate copper arsenate. Only a few grams of arsenic are extremely toxic to humans.  

CCA  is very effective at protecting wood from fungi and also kills off most insect pests such as termites. This is toxic lumber and not safe for humans or the environment when improperly handled.  

CA – Copper Azole – Brown

CA treated wood is almost completely odorless. Distinguished between Type A and Type B, Type A contains additional boric acid and Type B only contains copper and tebuconazole. It is typically very brown in color.

ACQ – Alkaline Copper Quat– Olive Colored

Alkaline copper quat is treated with copper and also contains a quaternary ammonium compound. It is very effective in shielding the wood from weather, fungus and termites.

Being a fairly strong wood, it is perfect for use as support for structures, such as beams and fences. It’s primarily got an olive colored hue to it.  

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Is Burning Pressure Treated Wood Dangerous?

Pressure-treated lumber is treated with a number of preservative chemicals that can be quite harmful to human health if ingested.

When the treated wood is burned, these toxic chemicals are released into the air. If these harmful chemicals are absorbed through the lungs, it could pose serious negative health effects.

When burning CCA-Treated timber for instance, dangerous wood preservatives such as arsenic, copper and chromium are released into the air and present a great risk to people. Apart from that, hazardous substances will be emitted into the environment when the wood releases toxic smoke.    

In most states it is unlawful to burn treated wood, particularly ACQ-Treated wood and CCA-Treated wood. If you are unsure about the wood you are burning, it’s better to confirm your local laws with your municipality.

Whether you are burning treated wood it in a fire pit, fire place, a wood stove, or residential boilers, it is never a good idea to burn pressure – treated wood.

Using untreated wood for this is always advisable. If you do burn treated wood be wary that the ashes remaining may be just as toxic as the toxic fumes released by the fire.

Is Old Treated Wood Still Toxic?

A main reason for the treatment process of this wood is to prolong its life span. Typically, you are looking at a lifespan of north of forty years until it might start decaying.

This makes this type of timber perfect for outdoor buildings. The main constituent chemical that makes this treated wood so strong and long-lasting is arsenic. This is a well – known toxic chemical that is often used by the wood treatment industry.

Studies have shown that the arsenic used in these types of timber, does not disappear over time. Even 20-year-old treated wood can expose you to potentially cancerous health risks.

Children that are playing on 25-year-old treated wood, used in jungle gyms or park benches, are just as exposed to these potentially harmful treated wood concentrates.  

So, if you have excess wood that has been lying in a pile in your backyard for the last 20 years, do not burn it, the chemical consistency does not disappear over time.

What To Do With Old Pressure Treated Wood?

This type of wood is extremely common because it is so widely used all over. Whether you are building a wooden deck or setting up a garden shed, for most outdoor projects, you will be using treated lumber.

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Due to this, you might have a lot of scrap wood lying around. The question is what to do with it, seeing as burning it is clearly a bad idea.

This type of wood is expensive enough, and one doesn’t usually want to spend even more money to get rid of old pressure treated wood. However, it is the responsible thing to do, not just to burn treated timber, but to make sure that these materials do not become hazardous waste.

Here Are Some Options That You Might Consider:

Give it away for free

“If you can haul it, you can have it.” Since the explosion of the online marketplace, scores of households are posting ad’s online for old wood scraps and furniture that are simply free for people to collect.

Even just piling the wood up on the sidewalk with a little notice reading “treated wood for free” can be an effective way of getting rid of unwanted wood items.  

Sell your treated wood

Seeing as timber prices are constantly on the rise, it may also be a good idea to sell it. If the treated wood is still in good condition and the cuts aren’t too small and still usable in minor projects, it would only make sense to resell the treated wood.

Outdoor treated lumber materials are always in high demand. Advertise them accordingly and someone is sure to take them off your hands.

Disposing of Pressure Treated Lumber

Pressure treated wood waste needs to be disposed of at an official wood disposal site. This is important, as pressure treated wood is considered hazardous waste by USEPA, and these woods can be a huge factor when it comes to soil pollution as well.

Over time these timber products might release toxic chemicals into soil they are lying on.

Anyone working with this material, should know exactly how the disposal process works and what it entails to getting rid of left over products of this nature.

For residential use, the treated wood waste needs to be disposed of at the local landfill. There is usually a designated area for disposing of this, it will be marked out (I.E., The Non-Clean Wood Pile).

If you are unsure about this, contact your local municipality and have a look at the regulations surrounding the subject matter. Do not burn treated wood waste, it is illegal.

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What Else Not To Do With Pressure Treated Lumber

Composting This Wood Is Extremely Hazardous

It can be a smart idea to compost old wood, so long as it is untreated. However, treated wood of any kind, even if it’s just stained wood can contaminate any adjacent soil or land.

Moreover, the toxic chemicals found in these woods will pass over into your compost and subsequently into the plants and gardens to which you transfer this compost.

Additionally, you could be positing the surrounding groundwater, tainting everything within the immediate region of your compost heap.

Do Not Cut It Up Into Smaller Pieces

It may seem like a smart idea to cut the treated wood up into smaller pieces so that they are easier to get rid of. If they fit into your conventional outdoor garbage, why not just throw them out, who’s going to notice?

This is a terrible idea! Cutting it into small pieces, allows for an even bigger chance for chemicals to leach out of the treated wood and into the environment.  

Ash is Also Dangerous.

Okay, so you have burnt some of this wood now, the ash should be perfectly safe to use in the garden right? – WRONG!!

Burning pressure – treated lumber yields extremely toxic ashes. Burning CCA wood means the ashes are particularly toxic. Avoiding contact with skin and eyes is extremely important as these toxic substances remain in the ash even after the wood has been burnt. As mentioned many times, burning treated wood at any rate is not good. 


Now you know the answer to the question, “can you burn pressure – treated wood?”.

In summary, it is clear that one should never burn pressure-treated wood, whether it would be in a wood burning stove or in a fire pit or in an outdoor fire.

Pressure treated wood is a dangerous commodity that needs to be handled with care and diligence and disposed of in the right manner. Even the burnt ash in your fire pit is still dangerous.

Burning treated wood releases toxic chemicals that are harmful to humans if breathed in and harmful to the environment

These chemical preservatives may protect timber against deterioration, but the environment and humans should not be exposed to them. Burning treated wood concentrates is a massive no go.