No abstract

The results are presented of a study of the overall mortality and the incidence of cancer in male workers producing ferrosilicon and ferrochromium. Although the study included all present and retired workers employed in the factory for more than one year from 1928 until 1977 inclusive, the incidence of cancer in those 976 workers who started work before 1 January 1960 was studied in particular. Both the overall mortality and the incidence ofcancer for all sites were lower than expected when compared with the national expected figures. Nine cases of lung cancer were found in the total population-seven in the ferrochromium subpopulation against expected rates of 3-1 and 1 8 when using national and local expected rates respectively as reference, and less than one expected case when using an internal reference population. A 1 5 O/E ratio was found for prostatic cancer in the whole study population. The results indicate that the increased incidence of lung cancer in the ferrochromium group has a causal relationship to occupational exposure. Perforation of the nasal septum was found in two present ferrochromium workers, and hexavalent chromium was found in the working atmosphere at the ferrochromium arc-furnaces during an industrial hygiene survey carried out in 1975. It is therefore concluded that the raised incidence of lung cancer is partly due to exposure to chromates. The results do not support the suggestion that exposure to chromic compounds entails a cancer hazard similar to that of exposure to hexavalent chromium compounds.Firm epidemiological evidence has been presented showing an association between prolonged inhalation of hexavalent chromium compounds and the development of cancer of the respiratory tract in exposed workers.' Such association has been shown both in workers exposed to dichromates2 3 and in workers exposed to chromium pigments.45 Increased incidence of cancer in the gastrointestinal tract has also been suggested in chromate workers by

This article in PubMed: www.ncbi.nlm.nih.gov/pubmed/3890162 Scand J Work Environ Health 11 (1985) 11 (1985) 65-74. Sixty-six cases of mica pneumoconiosis have been reported in the literature. Twenty-six of the cases suggest that pneumoconiosis may be caused by pure mica alone. In only six cases the diagnosis was based on clinical examination, radiography, and lung biopsy or autopsy results. In one of these six, doubt was raised by the authors about the purity of the mica exposure. Seven epidemiologic studieshave been performed among mica-processing workers, and these studies are all cross-sectional. In addition 30 experimental investigations have been carried out. However, there are no controlled inhalation studies among them. The results from the intratracheal instillation studies do not give a unanimous conclusion as to whether pure mica is fibrogenic or not. Present knowledge suggests that pure mica is moderately toxic and may induce pneumoconiosis. Exposure to mica is usually associated with exposure to other minerals such as quartz and feldspar. REVIEWS

The predominant asbestos fibre type used in the production of asbestos cement is chrysotile. The use of asbestos in relation to fibre type in a Norwegian asbestos cement plant during 1942-80 was 91.7% chrysotile, 3.1% amosite, 4.1% crocidolite, and 1.1% anthophyllite respectively. Electron microscopy and x ray microanalysis of lung tissue samples of asbestos cement workers who had died of malignant pleural mesothelioma or bronchogenic carcinoma showed a completely inverse ratio with regard to fibre type. The percentage of chrysotile asbestos in lung tissue varied between 0% and 9% whereas the corresponding numbers for the amphiboles were 76% and 99%. These differences are discussed with respect to the behaviour of different fibre types in the human body and to the occurrence of malignant mesothelioma in this asbestos cement factory.

GL! V. Anal ysis of asbesto s fibers and asbestos bodies in tissue samples from human lung. Scand J Work Environ Health II (1985) 107-110. In order to compare methods of counting asbestos fibers in lung tissue, seven laboratories participated in an interlaboratory trial in which tissue samples from five human lungs were anal yzed. In some laboratories, fiber concentrations were assessed with the light micro scope and, in others, with either scanning or transmission electron microscopes. Within each laboratory the ranking of the results was similar, but there were marked differences in the absolute values obtained by the different laboratories. It is concluded that the laboratories participating in this trial appear to produce internally consistent results, but there is difficulty in directly comparing results from one laboratory to the next.