Pneumoconiosis in boiler scalers.

Every six months or so the majority of steamdriven ships spend a few days in docks having their boilers scaled and cleaned. In the larger docks there are men who are employed full time in this occupation, but elsewhere and in industry generally the cleaning is more often done as an occasional job. The total number of men engaged in the work full time is not large, but the occupation is a very dusty one and carries a definite risk of pneumoconiosis. Some details of the processes involved were given by Harding, McRae Tod, and McLaughlin (1944). Working in very confined spaces the boiler scaler crawls along with a lamp and a hammer chipping off the scale as he goes; frequently the boiler is still very warm, and he works in a hot atmosphere. The considerable amount of dust comes from two sources: that produced by breaking off the scale deposited in the tubes from the water, and the flue dust in the fire tubes arising from the coal or other fuel. Although the boiler scale contains varying quantities of silica this is present mainly as silicate, and it seems likely that the flue dust is the more important since it may contain free silica from the coal. Cooke (1930) reported 26-4% of silica in a sample of flue dust, Harding and others (1944) 6-1 %, while in a sample taken recently in Hull we have found 10%. Since the original case described by Cooke (1930), there have been only three further reports of necropsy findings: Williams (1931), and Harding and others (1944 and 1947), but the clinical and radiological findings have been reported on a number of cases, notably by Dunner (1943), and Dunner and Hermon (1944). In this report we give an account of eight boiler scalers whose lungs we have examined in whole or in part.