Treated wood waste

Treated wood is a dangerous waste. Businesses that handle treated wood waste — most commonly construction and demolition sites — can often manage these materials according to exemptions to the Dangerous Waste Regulations.

Treated wood contains chemicals and pesticides that pose risks to human health and the environment, such as:

  • Arsenic.
  • Copper.
  • Chromium.
  • Pentachlorophenol.

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Not a business?

If you are a household or individual with treated wood waste, dispose of it in your trash collection. Do not burn treated wood waste, as it contains toxic chemicals.

How do businesses manage treated wood waste?

Determine if you can manage your treated wood waste under the treated wood exclusion. If you cannot manage your treated wood waste under the exclusion, then designate the waste and manage it accordingly.

Why is treated wood a dangerous waste?

Treated wood is full of pesticides that contain harmful chemicals. Wood is “treated” (i.e. dipped, sprayed, or pressure-treated) with chemicals in order to protect it from deterioration and natural decay caused by insects, fungi, and other environmental factors.

Common types of treated wood

Chromated copper arsenate

Chromated copper arsenate (a combination of chromium, copper, and arsenic) is one of the most common chemical formulations found in treated wood. Specific uses and disposal of this type of treated wood have raised safety issues, primarily because of arsenic.

Coal tar creosote

Coal tar creosote is the most widely used wood preservative in the United States. Creosote is the name used for a variety of products (wood creosote, coal tar creosote, coal tar, coal tar pitch, and coal tar pitch volatiles). These products are mixtures of many chemicals created by high-temperature treatment of beech and other woods, coal, or from the resin of the creosote bush.


Pentachlorophenol was once the most heavily used pesticide in the United States. It was used as a biocide and wood preservative. It's now only used on power-line poles, railroad ties, cross arms, and fence posts. 

What are the health risks of chemicals in treated wood?

All of the treated wood wastes named above have chemicals that can have a variety of adverse health and environmental risks. Learn more about each chemical's known risks:

Frequently asked questions