Wood for outdoor use is often impregnated with wood preservatives to protect the wood against rot and insect infestation. Wood preservatives and pressure treated wood can contain toxic substances such as creosote, arsenic, chromium and copper and can be harmful to both human health and the environment.

Wood preservatives and wood treated with wood preservatives

If you need to use a wood preservative, only buy agents that are approved by the Swedish Chemicals Agency. Approved preservatives always have a four-digit registration number and are divided into three authorisation classes. Products marked Class 3 may be used by anyone. In the Pesticides Register External link., you can check the registration number and see if the product is approved, what class it belongs to and find other important information.

How to reduce risks

  • Store wood preservatives out of reach and sight of children.
  • Do not use wood treated with wood preservatives indoors.
  • Look for the warning label and read the information that accompanies the product so that you are aware of the hazards associated with the product and know how to handle the product safely.
  • Consider whether you really need pressure treated wood for what you plan to build outdoors. For example, if you plan to build a sandbox or something else for children outdoors, it is good to use untreated wood and strengthen the wood with oil.

If you are planning to buy wood treated with wood preservatives

When you buy wood that has been treated with wood preservatives, the seller must be able to provide written information about the following:

  • active ingredients in the wood preservative,
  • restrictions on use,
  • how the lumber is processed appropriately,
  • health risks and safeguards,
  • how wood waste is to be disposed of.

Creosote-treated wood

Creosote-treated wood is black or brown and smells of tar. Creosote is made from coal tar and contains more than 200 substances, several of which can be allergenic and carcinogenic. When exposed to sun, the wood can sweat and the hazardous substances leak out.

Creosote-treated wood may still be present in old playgrounds and in private gardens. This type of wood, such as old railway sleepers and catenary poles, may no longer be used in playgrounds. As a private individual, you may only use creosote-treated wood that has been treated before 2003. Also, it must not be used for containers for cultivation, in parks, gardens or outdoor recreation facilities where there is a risk that it may frequently come into contact with the skin.

Leftover creosote-treated wood is regarded as environmentally hazardous waste. Check with your municipality to see what applies to such waste.

Last published 13 October 2021