Silicosis at autopsy in platinum mine workers

Introduction
South Africa is the largest producer of platinum in the world. Platinum is found in the Bushveld Complex , a volcanic intrusion containing many other minerals, including crystalline silica. The objective of this study was to explore the possibility of platinum mine workers developing silicosis.

Methods
Autopsies are performed at the National Institute for Occupational Health, for compensation purposes. Platinum mine workers, who had worked for more than a year and had silicotic nodules in the lungs and/or regional lymph glands, were identified from the autopsy database. Evidence of silica dust exposure, such as employment in the gold mining industry, was sought from a number of additional data sources, including the Medical Bureau of Occupational Diseases, The Employment Bureau of Africa, the Mine Workers Compensation database, company records, and friends and relatives.

Results
Less than 3% of the exclusive platinum mine workers employed for more than a year had silicosis in the lungs at autopsy, compared to 16% of those who had also worked in the gold mines. Silicotic nodules in the lymph glands were diagnosed in 13% of the exclusive platinum miners and in 43% of those with gold mining histories. After reviewing all the data sources, only 16 mine workers with silicotic nodules in the lungs and/or lymph glands fulfilled all the study inclusion criteria.

Discussion
Although much of the silicosis in platinum mine workers is likely to have been caused by exposure to crystalline silica in the gold mines, this case series indicates that platinum mine workers have a risk of developing silicosis even in the absence of a history of gold mining. Poorly documented employment histories were a major limitation in this study. Recording and archiving of comprehensive work histories should be mandatory to enable risks of disease to be quantified in future studies.