Disease of Lungs in Boiler Scalers: With a Case Report and Review of the Literature

Abstract

This article consists of a record of a fatal case of pulmonary disease in a boiler sealer together with a short introductory review of the literature of this little-known condition. The tubes, flues and fire boxes of all steam boilers have to be cleaned periodically, and during the cleaning process a good deal of dust is evolved. Ships' boilers are of two types: (1) the Scotch Marine Boiler in which the heat generated by the fuel passes through fire tubes surrounded by water which is converted into steam; and (2) the Water Tube Boiler in which the water circulates in tubes surrounded by hot gases generated by the fuel. In the first type, flue dust is found inside the fire tubes, and scale of mineral salts is deposited from the water on the outside of the tube. In the second type, the scale is inside and the flue dust outside the water tubes. The tubes of water tube boilers are scaled with an instrument fitted with rotating rollers and driven by air pressure, which is passed through the tubes; scale is removed from the exterior surfaces of fire tubes by means of a long pointed rod known as a slicing tool and by wire brushes. Flue dust in fire tubes or fire boxes is removed by brushing. Boiler sealers therefore are liable to inhale two types of dust: (1) the scale deposit from the water circulating in or outside the tubes; and (2) the dust in the fire tubes or fire boxes. The distinction is regarded as important because COOKE [this Bulletin, 1931, v. 6, 319] originally showed that the sample of boiler scale which he obtained contained much less silica than did the flue dust, viz., 6.4 per cent. as against 26.4 per cent. Cooke's original case was a man aged 35 who had worked for 9 0.5 years as a boiler cleaner. Autopsy revealed patchy fibrosis in both lungs with tuberculous lesions of a more recent date. Since the publication of Cooke's case, several small series of lung disease in boiler sealers have been reported, but only two autopsy reports are available, hence the importance of the case now recorded. The patient, aged 61, had been a boiler sealer for 47 years, working always on marine boilers. He was admitted to hospital with signs and symptoms suggesting pulmonary tuberculosis but no tubercle bacilli were found in his sputum (nine examinations). He was afebrile and the sedimentation rate was normal The radiogram showed nodular shadows throughout both lungs, more marked in the upper zones, together with some stippling and reticulation in the lower lobes. Five and a half years later he was readmitted. He had become emaciated, cyanosed and dyspnoeic. Another radiogram showed shadows similar to those previously found, but in addition there was a ground-glass opacity involving the whole of the right upper lobe. A provisional diagnosis of pneumoconiosis complicated by carcinoma of the lung was made, and he died nine days after admission. At autopsy a firm carcinomatous growth was found in the upper lobe of the right lung with secondary deposits in the mediastinum, in the sixth left and the seventh right rib, the muscle of the left ventricle near the apex, the right lobe of the liver, both kidneys, and the wall of the rectum. In addition, both lungs showed numerous small, hard, jet-black nodules, and emphysema was present. On microscopical examination the carcinoma was found to be of the squamous cell type whilst the black nodules were of the silicotic nodule type as seen in the lungs of coal miners. In addition pigment was found in abundance in all lobes, resembling the reticulation described by BELT and FERRIS [this Bulletin, 1942, v. 17, 512]. Incinerated sections showed that about one-third of the pigment consisted of iron, which occurred around the nodules of silicotic fibrosis but not within them (the authors, from previous experience, note that it may be impossible in ordinary stained sections to distinguish between carbon pigment and some iron pigments). No evidence of tuberculosis was found but there was an acute patchy pneumonia in the left upper lobe. The previously dried lung, wh