Pneumoconiosis of Kaolin Workers

Abstract

Kaolin, or china clay, is an important raw material which is exploited industrially in Cornwall, England, in Georgia, U.S.A., and in several other localities.In the past it has been assumed that exposure to kaolin dust does not lead to disabling pneumoconiosis, but over the past 10 years the experience of one of us in Cornwall has suggested that this may be incorrect.Difficulty has always been experienced, however, in obtaining an occupa- tional history uncomplicated by periods in other work carrying a silicosis risk, such as metal mining, granite dressing, or the like.In this communication, clinical and radiological observations of several cases will be described.Three of these men had worked at the same place in Cornwall, and had been engaged in drying and bagging disintegrated china clay.One of them came to necropsy in 1950, and the pathological findings and analyses of the mineral contents of the lung are given.Similar data are also given for a kaolin worker from Georgia, U.S.A. Working ConditionsWinning of china clay in Cornwall is generally carried out wet, and there is very little dust produced until the refined clay is dried and shipped.Until about 1920, the clay was dried in open sheds to a moisture content of 15 to 20%, and although some steam and dust were produced in these sheds, dust concentrations were not very high.Since that time, however, there has been a tendency to produce drier clay by the technique of filter pressing.Under these conditions much higher dust concentrations exist, especially in the drying plants where fine clays are disintegrated after drying and filled into bags.Three of the men described in the following case histories had worked in a plant of this type for over 20 years.Very high dust concentrations are also found in the holds of ships loading china clay.Clinical, Radiological, and Pathological Observations Case 1.-A man (C.P.) aged 44 years was first seen on March 15, 1949, complaining of shortness of breath, at rest as well as on activity, for four years past; some