Silicosis in the Potteries: Some Observations Based on Seven Hundred and Fifty Necropsies

Abstract

This paper, by a former member of the Medical Board for Silicosis, opens with a statistical table showing the occupational distribution of the 54, 822 persons who constitute the chief sections of the workers employed in the Potteries industries of North Staffordshire, according to the latest returns of the Ministry of Labour. The largest section is that of the operatives in general earthenware manufacture, which employs 25, 387 workers. Women and girls constitute 55 per cent, of all operatives but they are mainly employed in the manufacture of tiles and in decorating processes. Over the last 17 years the annual incidence of deaths from silicosis and silicosis accompanied by tuberculosis has been 44. It is the practice for a member of the Medical Board to attend necropsies wherever possible, and this paper sets forth the records of 750 such examinations, which is believed to be the largest group to come under the observation of one observer for any single industry or process in Great Britain. A table is given showing that the average age at death for silicosis or silicosis accompanied by tuberculosis has risen from 56.6 in 1932 to 62.5 in 1948. No deaths from these diseases have been recorded in the manufacture of Jet and Rockingham ware which consists in the making of brown teapots from local marls and which employs only 1, 753 persons, the smallest group in the whole of this pottery worker series. Of the total of 750 necropsies silicosis was present in 217 (28.9 per cent.), silicosis accompanied by tuberculosis in 241 (32.1 per cent.), other causes (but silicosis also present) in 142 (19.0 per cent.) and other causes with no silicosis in 150 (20.0 per cent.). An analysis of these causes of death according to occupation or process is given in the table below. In the group of 150 cases in which there was no evidence of silicosis, even after histological investigation, some selection was unavoidable in that only those cases were reported to the coroner which might possibly reveal this disease. A predominance of respiratory disease other than silicosis in this group is therefore of no statistical significance. [img 1T251807.tif] With regard to the operative processes in the industry, the china manufacturing side (i.e., clay processes) produces English bone china composed of' Cornish stone, china clay and calcined bone. Unlike the earthenware section, there is no added flint or free silica. There is little or no interchange of labour between the china or earthenware sections of the industry or between flint and clay processes. But to some extent, before the introduction of alumina, powdered flint was used as a parting powder on the boards on which the chinaware is carried; and there was universal contamination of all working places by flint from placing shops, ovens and the china biscuit warehouse-indeed, powdered flint was dispersed inta the adjoining streets. Nevertheless when all the relevant facts are reviewed it has always been difficult to account for cases of silicosis in the clay processes of china manufacture. There were altogether 359 cases in which silicosis was present, without tuberculosis, at necropsy. In 217 this disease was regarded as the primary cause of death, and in the remaining 142 death was attributed to other causes "such silicosis as existed being considered unrelated and non-contributory ". In the lung, adhesions were usually sessile and tough, and ultimately led to complete obliterative pleurisy. Apical plaques of pleural thickening almost like cartilage in appearance were also noted. Involvement of intrathoracic nerves and traction diverticula of the oesophagus were rare. Bullous emphysema was frequent, frank bronchiectasis exceedingly rare. Clubbing of fingers and toes was not a feature of silicosis. In the early stages of the disease tiny sub-pleural nodules like sago pearls, with an areola of carbon pigment, protruded, from the lung, surface, and the hilum glands were enlarged, fibrotic, rubbery and deeply pigmented. (Generally speaking, if these glands