An increased incidence ofhaematopoietic cancers, espe- cially acute myeloid leukaemia (AML) and multiple mye- ooms, loma, has been found among Norwegian offshore al operators. However, the possible causes are not clear at this time and require further study. It is possible that some non- ontrol occupational factors, such as smoking or exposure to radia- ed on tion arising from industrial or natural sources not associated with employment, could play a role. The conclusion drawn by the Norwegian investigators that the increased incidence of AML was most probably associated with benzene expo- sure was speculative and not substantiated by the evidence.