[Evaluation of the work environment in factories producing artificial mineral fibers (MMMF)]

In seven MMMF producing plants, workplaces have been evaluated through measurements of the concentrations of the total dust and respirable fibers of over 5 micron length and below 3 micron diameter, using personal dosimeters of Cassella firm. Only in one of the plants the time weighted average concentration of total dust was 4.11 mg/m3, exceeding the TLV value (4.0 mg/m3). Respirable fibers concentrations ranged from 0.005 to 1.44 fibres/cm3, so in none of the plants the TLV value of 2 fibres/cm3 was reached. The greatest air dustiness was found at mineral wool spreading and breaking workplaces. However, such workplaces occur only in two plants using the oldest technology of MMMF production. Analyses of fibres sizes made with the use of optical and electron microscopy indicated that the contribution of respirable fibres to the total dust weight is slight, up to a dozen per cent.