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Burning Treated Wood: Is it Safe? 3 Best Practices and Precautions

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Woodworkers love treated lumbers due to their improved strength and water-resistant qualities. Wood treated with the appropriate materials can be used for outdoor projects and activities requiring high durabilities. Treated lumber is a joy to use; however, it can become challenging to discard after it exceeds its lifespan.

The first thought is often to burn wood that you no longer need; while this is allowed for regular lumber, it poses significant concerns in pressure-treated wood. If you have treated timber you want to dispose of, burning it can harm your health.

If you’re wondering whether it is safe to burn treated lumber, the short answer is no. Setting this type of wood flame exposes you to damaging effects. We’ll see all about burning treated wood in this guide. If you want to know why it is a bad idea to burn treated lumber, follow this piece, but first, what is treated lumber?

What is Treated Lumber?

What is Treated Lumber?

Treated timber is wood that has seen chemicals added to it to improve its durability and lifespan. There are different treatment procedures for lumber, with pressure treatment being the most popular. The goal of treated wood is to enhance the lumber’s quality to be used in delicate areas with high moisture content and pest attacks.

The chemical preservatives added to pressure-treated wood make them suitable for projects where structural degradation is rampant. Railings, decks, and fences are some projects where the wood sees a lot of pressure from the environment and human activities, making it susceptible to damage. Using pressure-treated wood in this project will ensure a longer lifespan.

There are three types of treated lumber, borate, alkaline copper quaternary, and non-combustible lumber. Borate lumber is treated with a water-based mineral salt solution that helps the wood retain its natural color. On the other hand, alkaline copper quaternary is treated using environmentally friendly solutions of copper and alkyl. Non-combustible types are better suited for industrial uses.

How Treated Wood is Made?

Understanding how treated wood is made can reveal why burning this wood can be detrimental. Considering how it is produced and the materials used, you should take a second thought before setting it ablaze. While we know treated timber has added preservative chemicals, we want to see how this is done and the type of chemicals used.

Pressure-treating wood involves two major processes; removing air and adding preservative chemicals. Typically, a vacuum chamber eliminates the air in the wood, creating enough space to pump in the needed chemicals that improves the wood’s quality.

The wood is shut in a tank, and then air is extracted from the wood, creating an air vacuum inside the tank. By this time, the necessary elements are pumped into the tank and are absorbed by the now spacious wood. The vacuum created forces the chemicals into the wood.

The chemicals infused into the wood involve safe and highly toxic materials and are handled cautiously. The three primary chemicals injected into the lumber are Chromium, Copper, and Arsenic, typically in a solution. This solution is the reason treated timber is often called CCA wood.

Older treated wood contains creosote, a harmful oil-based compound capable of causing fetal issues and birth complications. Copper naphthalene, insecticides, and pesticides are other compounds injected into the wood to improve its immunity.

Is Burning Treated Wood Safe?

Is Burning Treated Wood Safe?

Now to the throbbing question, can you burn treated wood? Treated lumber burns like any other wood type, so yes, you can burn it. The real question is, should you burn treated lumber? And the answer to that is a resounding no; even though you can burn treated timber, you should not.

The chemicals used to make this enhanced wood are highly toxic, and setting them ablaze releases the materials into the atmosphere. In most countries, including the USA, burning treated lumber is illegal due to the high level of toxic waste it expels. Not only during burning through the air, but the ash left behind is just as dangerous.

Copper is a heavy metal and remains in the ground as ash after burning, with the ash contaminating everything it touches if not properly discarded. It gets even worse with arsenic, tagged as the silent killer since it has no smell or taste. You won’t notice its presence, so it can cause severe damage without people around it having a clue.

You should avoid any open burning of treated wood, with no exceptions. While the lumber can be burned in a controlled environment involving a closed space with a proper ash disposal system, residential areas do not have such facilities.

Burning treated lumber in fireplaces and firepits confines the chemicals to a small area, increasing their concentration. While burning outdoor spaces is less toxic, avoiding it and seeking better alternatives to dispose of your wood is best.

How to Identify Treated Lumber?

You know how dangerous and illegal burning treated wood can be by now, but how do you identify this type? Treated wood is similar to untreated lumber, making it difficult to tell the difference. CCA-treated wood has a distinct OD green hue caused by the chemical solution injected into it; however, this is only always visible. Some have a dark-brown shade, which can be likened to other standard wood types.

Identifying other types of pressure-treated lumber gets even more challenging as they sport fewer differences from the standard type. You may have to take the wood for testing in a laboratory to get a definite answer. One way to be sure if a piece of wood is tested is if you purchased it and can remember the type of lumber. If you need more clarification on the kind of wood you purchased, it is best to take it as treated wood and avoid burning.

Looking closely, you may notice incisions on all four sides in treated lumber. These marks are where the chemicals were infused into the wood. So physically inspect the wood for incisions to determine if it is treated. Remember, spotting these openings as the wood ages becomes challenging.

How to Dispose of Old Treated Wood?

How to Dispose of Old Treated Wood?

Instead of setting the wood ablaze and exposing yourself to harmful materials, you can discard it by taking it to a local landfill or disposal center. These places collect toxic wastes and dispose of them adequately. However, call first to ensure they accept treated wood before taking it there, as there might be limitations.

These landfills usually charge a small fee, but it’s worth it as it protects you from the harmful toxins in the wood and prevents you from breaking the law. You may need a truck to move the wood if it is significant. Ensure to place the treated wood in the contaminated pile in the landfill rather than with scrap wood.

Another alternative is to continue using the wood for simple tasks like landscaping for as long as it remains usable. You can also donate the wood to people or organizations needing it. However, ensure to state that the wood is treated and shouldn’t be burned.

What are the Best Practices for Burning Treated Wood?

While burning treated wood is frowned upon, if you must burn this wood, you must take into consideration some vital tips. This will ensure your safety and reduce the risk of health implications. However, before proceeding, ensure that burning this wood is not illegal in your locality.

  • Only burn in well-ventilated areas to encourage the quick dissipation of the harmful gases, as the chemicals are blown away with the wind. Enclosed spaces keep the fumes trapped and increase your exposure
  • Wear protective gear, including mask, clothing, and goggles. These materials will block the gases from coming in contact with your skin and entering your nostrils
  • Avoid burning treated wood that is less than six months. It takes time for the chemicals to dissipate, and six months is a typical period for the infused chemicals to reduce, helping lessen their toxicity

What Precautions to Take When Burning Treated Wood?

What Precautions to Take When Burning Treated Wood?

You have to take extreme measures to prevent some of the dangerous effects of burning treated wood. While setting this lumber ablaze is still frowned upon, here are a few precautions to take if you must burn treated wood:

  • Keep children and pets out of the area as they are prone to complications with minimal exposure. Some of the most common damages include neurological organ failure and respiratory system blockage
  • Never burn treated wood indoors, as it confines the gases to a small space and increases toxicity
  • Properly dispose of the ash after burning, as it consists of dangerous copper. Pack all the ash and dispose it separately in local landfills


If you have concerns about burning treated wood, consider this section that features popular questions and their answers.

Q1. What happens when treated wood is burned?

Ans: When treated wood is burned, it breaks the layer of protection, trapping the chemicals on the surfaces, thus releasing them into the atmosphere. As the wood burns down, the gases injected into it are let loose and can roam without hindrance, causing a lot of damage to humans and the environment. Remember, burning the wood will not destroy the chemicals in it.

Q2. What health challenges can burning treated wood cause?

Ans: If you burn treated wood, you release the chemicals used in the treatment, which can cause respiratory problems such as bronchitis, birth and fetal challenges, cancer, and issues with the brain.

Q3. What are the environmental impacts of setting treated lumber ablaze?

Ans: Setting treated wood ablaze affects humans and can negatively impact the environment. Air pollution is the primary environmental impact of burning treated wood. Soil and water pollution are other problems the environment faces.


Treated wood is an enhanced wood infused with preservative chemicals, ensuring better durability. However, discarding the wood can be problematic, considering burning is discouraged. Burning this wood releases the chemicals used to make it, which contain a lot of toxins.

The best way to handle old treated wood is to take it to local landfills and waste disposal centers. You can also continue using it for projects or donate to others.