ASBESTOS EXPOSURE IN A STEAM-ELECTRIC GENERATING PLANT

A study on asbestos risk in an old multi-fuel-fired steam-electric power station was carried out. In spite of the presence of large amounts of asbestos-containing materials (20 km of asbestos insulated pipes), the mean airborne concentration of asbestos was as low as 1.55 fibres 1.(-1)(SD 2.05) under normal operating conditions. Much higher concentrations may obviously occur during maintenance or renovation operations. Man-made mineral fibres (MMMF) were detected only occasionally in some samples. Three non-consecutive sputum samples were collected for all the 521 workers included in the study: 3.1% had asbestos bodies (AB), but in no case were there more than four AB per gramme sputum. Small opacities, in most cases irregular or of mixed type, were present in 15 out of 470 radiograms of acceptable quality (3.2%). No AB were found in these cases. Pleural changes were less common (1O cases, 2.1%): two out of five bilateral cases had AB in the sputum. It is concluded that repeated AB counts in the sputum turned out to be more useful than the search of pleural abnormalities by traditional postero-anterior (PA) view in detecting the signs of low asbestos exposure.