Creosote or pitch oil is a coal tar distillation product that is an efficient and toxic wood preservation chemical. It is used for the industrial impregnation of items such as railway sleepers and poles. Creosote-treated wood is dark brown and has a characteristic odour. Creosote oil consists of hundreds of organic compounds, most of which are detrimental to the environment or health.
The use of timber treated with creosote oil is restricted under an amendment to Annex XVII to the REACH Regulation (552/2009) relating to the restrictions on the manufacture, placing on the market and use of certain dangerous substances, mixtures and articles. According to the amendment, creosote-impregnated timber is only intended for professional users, not for private consumption. Creosote-treated wood may only be used in overhead wire structures (electric power line and other poles) in permanent ground contact, railway sleepers or bridges and other corresponding load-bearing exterior structures.
The use of creosote-impregnated timber indoors, in contact with food plants or animal feeds and in playgrounds and other outdoor recreational areas where repeated skin contact exposure is possible has been banned since 20 June 1996 (Government decision 1405/1995). The use of creosote-impregnated timber in garden furniture and toys has been prohibited since 30 June 2003 (Government decree 8/2003).
Creosote can cause skin, eye and respiratory irritation. It may also cause allergic skin reactions, particularly in sunlight. Long-term or high-level exposure may have carcinogenic or mutagenic effects. Such exposure may take place in contexts including when breathing in creosote oil fumes (such as when impregnating timber) or if large amounts of creosote is found in food (food may be contaminated by creosote if stored in a creosote-treated wooden container, etc). Particular care should be exercised when working on or otherwise handing creosote-impregnated wood. If necessary, personal protective equipment should be used to minimise skin and other exposure (breathing in wood dust in particular).
Creosote oil is not absorbed permanently in wood. Instead, it is dissolved and vaporised into the environment. The characteristic odour remains in creosote-treated wood throughout its use life. The components of creosote may contaminate groundwater and be detrimental to soil and aquatic organisms. Therefore timber impregnated with creosote should not be used or stored near wells or in groundwater areas.
Since 2002 discarded creosote-impregnated wood has been regarded as hazardous waste. Therefore it must be taken to a hazardous waste collection point and must not be handed over to consumers. It may not be burned in households either.