Document DjOJLwv8Mdp5X9pYgDoqLBNM

February 1948 Industrial Hygiene Newsletter 5 Some Thoughts on Silicosis L. E. Hamlin, M. D., American Brake Shoe Co* Silicosis, perhaps more than any other condition, has demonstrated the inex actitude of diagnostic standards for occupational disease. For exam pic, the work of Gardner and other investigators has shown that, far from being fatal, the uncomplicated form is nondisabling except in extreme degrees of fibrosis. There has been so much intensive study of silicosis that it might appear that little remains to be done. Complacency amounting to boredom has crept into the picture, and on occasion speakers discussing the subject have been intro duced with a note of apology for bring ing up such a shopworn, dusty topic. A few individuals imbued with un justified optimism have even predicted that since we have learned everything about silicosis, the application of modern methods of control will soon make the disease another vanishing entity. Unfortunately, the experience of the last few years does not substantiate this rosy outlook. Tremendous advances have been made in controlling the hazard but knowledge of these often seems to be lacking, especially in those quarters where it is most urgently needed. Physicians, industrial and otherwise, still make a diagnosis of occupational fibrosis because of the chest X-ray pattern and/or a history of employment in a supposedly dusty industry. No consideration is given to the fact that dependable estimations of respirable sized particles of dangerous dust and safe atmospheric concentra tions have been established. The plant physician is frequently unaware that such standards exist and management has been lax in bringing the matter to his attention. Industrial compensation commissions need to be reminded that CHEST CONDITIONS WHOSE X-RAYS SIMULATE SILICOSIS A, Industrial I. Organic. II. Inorganic. Iiiert Toxic Proliferative (a) Byssinosis. (b) Bagassosis. (c) Tabacosis. (a) Anthracosis. (b) Radiopaque Deposits-- /Barium (Baritosis). < Iron (Siderosis). tTin. (c) Beryllium. (d) Asbestosis. B. Nonindustrial I- Mycotic.................................... ..................... Yeasts and Molds II. Miscellaneous.............. ................................. (a) Aspergillosis. (b) Moniliasis. (c) Wood dust spores. (d) Coccidioidomycosis. (e) Blastomycosis. (f) Actinomycosis. (a) Miliary tuberculosis. (b) Sarcoidosis. (c) Mitral Stenosis. (d) Cancer (Metastases), (e) Vascular changes. (f) Miliary calcicosis (Wheatena). (g) Polycythaemia Vera. (!)) Bronchiolitis. consideration of these factors is essential before awards for disability, based on vague roentgenographic shadows and uncertain exposures, should be granted or upheld. As more unrelated conditions whose X-ray appearances closely simulate silicosis are recognized, the unreliability of the roentgenogram alone as a diagnos tic measure becomes obvious and accur ate interpretation is correspondingly difficult. A situation of this kind points out the necessity of accumulating factual data on exposure through industrial hygiene surveys. Such appraisals must include enough samples to be truly representa tive. They should faithfully portray actual working conditions and environ mental hazards. One should not be concerned so much with the amount of visible dust in the atmosphere of a working place as with the number of harmful particles that actually reach the alveoli of the lungs and are retained. We have seen reporta of plant surveys where obviously the hygienist has been too impressed with visible dust around a shake-out where careful analysis revealed mostly smoke, steam, and carbon particles with free silica well below accepted safe limits. This same individual missed a really serious dust hazard where free silica was present in high concentrations but was not evident because the general atmosphere ap peared to be clean. In recent years considerable attention has been given to nodular patterns observed in the X-rays of workers ex posed to significant concentrations of iron dust. Reports from this country and abroad have shown that such ex posures are capable of producing shad ows almost identical with those of silicosis, even in occupations where teste indicate a practically complete absence of free silica in the atmosphere. Post mortem findings on some of these indi viduals have demonstrated only simple deposits of iron particles in the lungs with no evidence of fibrosis. We have noted similar X-ray changes in certain grinders and burners in the foundry industry. The shadows have appeared in comparatively short periods of time, the average being about 6 years. Analysts of the air-borne dust in these locations by counts. X-ray diffraction, and estimations of particle size and per- (Continued on page 16) SPNY 000317