A report on the environmental conditions at seven European ceramie fibre plants

As part of an epidemiological study which was co-ordinated by the University of Birmingham in the European Ceramic Fibre Industry, the Institute of Occupational Medicine has carried out a series of occupational hygiene investigations in seven production plants. This report presents the results from surveys and the rationale and methods used to calculate each worker’s cumulative exposure to airborne dust and fibres. The results from the epidemiological study are described in a companion report.In each of the factories included in the study, a comprehensive occupational hygiene survey was undertaken. Workers were selected at random from within occupational groups and full shift personal dust samples obtained. Respirable and non-respirable fibre concentrations and total mass concentrations were obtained using the WHO/EURO MMMF Reference Method. Measurements of inspirable mass, respirable mass and silica and fibre size were also made.Individual respirable fibre concentrations ranged up to 2.4 fibres/ml in the case of production workers and 3.4 fibres/ml for secondary production workers. The plant average concentrations for production workers ranged from 0.2 fibres/ml at one plant to 0.88 at another. Corresponding mean respirable fibre concentrations for secondary production ranged from 0.49 fibres/ml to 1.36 fibres/ml. The respirable fibre levels in other groups were substantially lower, typically less than 0.5 fibres/ml.The mean mass concentrations of inspirable dust for production workers ranged from 1.4 mg/m3 to 3.8 mg/m3. The highest individual concentration for this group was 11.4 mg/m3. The corresponding range for secondary production workers was 0.8 mg/m3 to 7.4 mg/m3.Inspirable and total mass concentrations were reasonably well correlated (r = 0.7),with the inspirable mass in general being slightly higher.The relationship between these two measures was used to predict inspirable mass concentration for the purposes of estimating exposure.Respirable mass and silica concentrations were generally low less than 1 mg/m3 and 0.1 mg/m3 respectively, the highest individual concentrations measured were 2.8 mg/m3 and 0.25 mg/m3 respectively. Crystalline silica was detected on approximately 50% of the samples. The nominal fibre diameter of bulk ceramic fibres was found to range from 0.8 �m to 2.8 �m. The airborne fibres were thinner; geometric mean diameter ranged from 0.5 to 1.3 /xm and mean lengths from 3.9 pm to 25.2 /�m.irmingham. The occupational hygiene data used in these calculations were combined across groups and plants where no differences were identified in the statistical analysis. “”