Annals of Occupational Hygiene Advance Access originally published online on July 2, 2007
Annals of Occupational Hygiene 2007 51(6):509-516; doi:10.1093/annhyg/mem027
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Exposure to Refractory Ceramic Fibres in the Metal Industry
1 Finnish Institute of Occupational Health, P.O. Box 93, FI-70701 Kuopio, Finland
2 Finnish Institute of Occupational Health, Topeliuksenkatu 41 a A, FI-00250 Helsinki, Finland
3 University of Kuopio, P.O. Box 1627, FI-70211 Kuopio, Finland
4 Ministry of Social Affairs and Health, P.O. Box 33, FI-00023 Government, Finland
* Author to whom correspondence should be addressed. Tel: +358 30 474 7232; fax: +358 30 474 7474; e-mail: markku.linnainmaa{at}ttl.fi
Refractory ceramic fibres (RCF) are used in thermal isolation in the metal industry where high temperatures are regularly employed. Asbestos materials were earlier commonly used for these purposes. In this work, two Finnish steel plants, three foundries and a repair shop were studied for the ceramic fibre exposure of their workers under normal production and during the replacement of oven insulation. Personal and stationary sampling was used together with a novel nasal lavage sampling for the evaluation of personal exposure. Fibres were counted with optical and electron microscopy and they were identified using an energy-dispersive X-ray analyser. Ceramic fibres were found in most production phases [range <0.01–0.29 fibres per cubic centimetre (f cm–3)]. Considerably higher fibre counts were obtained during the maintenance work (range <0.01–14.2 f cm–3). Nasal sampling was found to correlate with the airborne fibre concentrations at the group level. The mean fibre concentrations varied from 34 to 6680 f ml–1 of lavage liquid. Use of personal respiratory protectors diminished the exposure on the average as analysed in the lavage specimens, but the effect of respirator use did not appear clearly in the results. Because of the heat conditions, the workers used the respirators for a strict minimum period. A considerable exposure to RCF occurs in the studied plants. Its risk should be evaluated and managed more closely in view that the material is carcinogenic. Use of personal respiratory protectors should be encouraged. Their effective use could be verified by the nasal sampling for fibres after the work shift.
Keywords: exposure • foundries • nasal sampling • refractory ceramic fibres • respirators • steel plants
Received November 27, 2006; in final form April 27, 2007