[Possible carcinogenic risk associated with production and use of creosote-treated wood]

Creosote is a coal tar product which contains varying amounts of mutagenic and carcinogenic substances such as polycyclic aromatic hydrocarbons (PAHs) and benzene. Marketing and use of creosote and preparations containing creosote, as well as creosote-treated wood, are regulated by a EU Directive. According to the EU classification of such mixtures, inclusion of a warning against creosote as a carcinogen is not necessary if the contents of benzo[a]pyrene (BaP) and benzene are lower than 50 ppm (parts per million) and 1000 ppm, respectively. A recent well designed skin painting study in mice clearly indicates that the creosote preparations had a five-fold higher potency to induce skin cancer than the potency based on BaP content. Furthermore, it was estimated that creosote containing 50 ppm BaP would induce a significant incidence of skin cancer. Preliminary results from determination of concentrations of various carcinogens (BaP and benzene) in the air close to creosote impregnation plants as well as the crudely estimated exposure of children to dermal contact with creosote-treated wood, indicate that the life-time cancer risk from such exposures is in the order of one per 10,000. Despite the uncertainty related to such estimates, these risk levels give reasons for some concern. A further reduction in the content of PAH and benzene in creosote preparations should be considered.