Health Canada

Health Canada

July 20, 2011 11:19 ET

Information Update: Treated Wood is Not Firewood

OTTAWA, ONTARIO--(Marketwire - July 20, 2011) - Health Canada is reminding Canadians not to burn pressure- or surface-treated wood.

Both types of treated wood are considered safe when used as intended, but should never be burned. Whether on a bonfire or in your fireplace, burning treated lumber products can release highly toxic chemicals that may make you sick. Wood preservatives such as creosote, pentachlorophenol or chromated copper arsenate (CCA) are pesticide products that help protect wood from insects and other pests but can be hazardous to your health if not handled properly.

Burning treated lumber can release the preservative chemicals into the air, where they can be breathed in. The ash can also contain dangerous concentrations of the same chemicals. If you suspect that you have burned treated wood, dispose of the ashes according to your local waste regulations.

Treated wood is primarily for outdoor use, such as construction lumber, utility poles, marine timbers and pilings, as well as outdoor playgrounds. Pressure-treated wood has had a penetrating chemical preservative applied to it prior to sale, while surface-treated wood has been brushed, sprayed or dipped with a preservative agent. If you have leftover treated wood from a recent outdoor construction project, dispose of it according to your local waste regulations.

Keep the following tips in mind before building a fire:

  • Know your wood. Use only dry, clean, natural wood. Wood should be cut, split and stacked in a covered area for about six months before burning.
  • Never burn wood you suspect may be treated. Treated wood cannot always be readily identified. If you are unsure if wood has been treated, do not dispose of it by burning.
  • If you accidentally inhale smoke or ash from wood you suspect has been treated, you should contact your local poison control centre or your doctor.

Health Canada has several helpful tips about handling treated wood ( on its website. Please visit our fact sheet entitled "Chromated Copper Arsenate Treated Wood. ("

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