Do you know what you’re burning?
UPdate spring 2005

As energy prices rise, more people are burning wood. Most people are aware of basic wood burning safety precautions, such as having flues and chimneys cleaned and inspected regularly. But here’s another burning safety issue which few people have thought about -- everything that creates heat isn’t safe to burn.

Many people think its a good idea to burn up old scrap wood, like an old deck or old plywood. They think they are helping the environment, or want to save a few dollars on dump fees. Some contractors may even suggest burning waste from a project to save you money on dumping. A word to the wise - DON’T!

Burning anything other than dry firewood can be very risky. Many building materials contain chemicals which were never meant to be burned. Burning some wood products will expose you to toxic chemicals and heavy metals you didn’t even know were there. Smoke particles can be deeply inhaled, which makes them especially hazardous. Ash left from burning hazardous materials may contain concentrated amounts of chemicals and heavy metals.

  • Don’t burn any type of treated wood. Old decks were often built of pressure treated wood, which contains arsenic and chromium. Older treated wood loses its greenish colour, so you can’t tell if its treated. Wood treated with creosote is also extremely toxic when burned. Burning either is prohibited anywhere in Canada.

  • Don’t burn any wood that has been painted or stained. Paints used until 1978 contained lead, paints used until 1990 contained mercury. Paints containing PCBs were widely used from the 1940s to the 1970s to improve durability and flexibility and to improve resistance to fire damage and moisture. “Burning wood and other materials coated with paint containing PCBs results in much higher exposure to the harmful chemicals,” cautions Health Canada, “but an even greater concern is the danger of exposure to dioxins and furans, which are produced when PCBs are burned at lower temperatures.” Old stains may also contain toxic ingredients. Even some new paints include ingredients which should never be burned, for example paints containing Teflon which produces a very hazardous gas if burned.

  • Don’t burn particleboard, plywood or other composite wood products. These products are held together by glues which may contain cyanide and other extremely hazardous substances. Old sub flooring and furniture are often made of composite wood products.

  • Don’t burn wood from orchards which have been sprayed with pesticides. The Lung Association warns that burning wood containing pesticides can be very hazardous.

  • “Never burn magazines, gift wrap, or colored paper,” warns the US Department of Energy. “They all produce particles that can clog a fireplace or wood stove's air passages and can also produce noxious, corrosive or even carcinogenic gases.”

“The problem with burning things other than firewood is that you do not know what could be an ingredient in a seemingly harmless product,” says health advocate Deborah Barrie. “The money saved from disposal fees will never make up for the cost to your health or even touch the cleanup on the home.” Barrie herself became permanently disabled from a neighbor who burned CCA pressure treated wood in his garage hobby shop. She now works to assist people who have become sick from exposures to treated wood.

Burn Wise: trying to save a few dollars by burning hazardous wood products could cost you your health, require very costly cleanup to your home, and harm the environment.