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Statistics in brief - Wood preservatives

Many different kinds of products are used to protect and preserve wood surfaces and wood materials. Some wood preservatives work by keeping out water e.g. different oils, whereas other products are toxic to organisms that decompose wood.

For a long time, the latter type of products have been legally treated as pesticides in Sweden and they must be authorised before use. They are mostly added to the wood material through impregnation but there are also wood preservatives that are applied on the surface.

A wood preservative consists of the substance that is active against organisms and different auxiliary chemicals like solvents, emulsifiers and fixatives.

Quantity of imported/manufactured wood preservatives and sold quantity of active substance

Graph - Quantity of imported/manufactured wood preservatives and sold quantity active substance in such.

Source: Products Register, Swedish Chemicals Agency 2010.

In 2010, there were 85 approved pesticides intended to preserve wood. This year there were also about 100 other wood preservatives that were not pesticides. The quantity of wood preservatives has increased with 300 per cent since 1999, but the quantity of active substances in wood preservatives that are approved pesticides has not increased. The increase seems to depend on the fact that use of wood preservatives that are not intended to act by their toxicity to micro-organisms, e.g. wood oil, has grown. An alternative explanation could be that the active substances have been more diluted so that the total product quantity increases. 

The largest quantity of pesticides is used for pressure and vacuum impregnation of wood. Annually about 6,000 to 8,000 tonnes of active substances are used for this purpose. The Swedish production of impregnated wood has grown with over 100 per cent since 1999 and in 2010 it was about 1,300,000 m3.

Substances (except water) that are contained in largest number of wood preservatives

  • Linseed oil
  • Different solvent naphthas
  • Propiconazole
  • 3-Iodo-2-propynylbutyl carbamate
  • Cobalt ethylhexanoate
  • Boric acid
  • Butoxipropanol
  • Monoethanolamine
  • Basic copper carbonate
  • Ammonium hydroxide
  • Tebuconazole
  • Pine tar

Source: Products Register, Swedish Chemicals Agency 2010.

Several of the substances above are specially developed to act as pesticides. The largest active substance by far is creosote, a coal tar product used for impregnation. In 2010 the sale of creosote was 4,605 tonnes. Additional active substances in wood preservatives can be found in the KemI-stat search tool by searching in the Use and Product type fields.