OBJECTIVE Regulations to certify nasal carcinoma as occupational disease induced by wood dust vary in the European countries. In Germany, it must be adenocarcinoma and the dust originating from beech or oak trees. In other countries, the disease is reconized as induced by occupation independent of the kind of wood dust or the type of carcinoma. With regard to the harmonization of regulations necessary in Europe we investigate whether these differences are acceptable from the scientific viewpoint. METHODS In a retrospective analysis of a group of 28 patients with wood dust-induced nasal carcinoma in North Rhine-Westphalia, Germany, we studied whether significant differences in exposure, personal risks (smoking) and histological tumor type could justify the current German, Austrian and Luxembourg pattern of occupational disease certification. To quantify cumulative time of exposure we developed a new semiquantitative formula for the calculation of wood dust years (WDY). RESULTS Our results indicate that there are no significant differences between the subgroups, i.e., exposure to hard wood (n = 13) or other woods (n = 15), WDY (13.1 +/- 11.3), smoking (n = 17) or nonsmoking, type of work and the diagnosis of nasal squamous cell carcinoma (n = 8) versus nasal adenocarcinoma (n = 20). The review of literature suggests systematic errors in the studies that led to the current German regulations. CONCLUSIONS We recommend to amend the German, Austrian and Luxembourg regulations and to recognise nasal carcinomas as occupational disease, regardless of the type of wood dust exposure, and regardless of the tumor histology as also recommended by the International Agency for Research on Cancer (IARC).