In a very well written and interesting study Saliet al found an increased mortality due to ischaemic heart disease (IHD) among European workers producing rock or slag wool and continuous filament after 30 years since first employment.1 These types of fibres belong to a group called man made vitreous fibres (MMVF). Other types in this group are ceramic fibres and glass fibres.

These groups of European workers have been compared with the national death rates of the respective countries.1 This comparison is most often regarded as an underestimation of the true risk as the general population includes …