Silicosis at autopsy in platinum mine workers

Abstract

Background: South Africa is the largest producer of platinum group metals in the world. Platinum is found in the Bushveld Complex in the north-east of the country. This volcanic intrusion contains many other minerals, including crystalline silica. Little is known about the health risks in the platinum mining industry.

Aims: To explore the potential for platinum mine workers to develop 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 silicosis and/or fibrotic nodules in the lymph nodes, were identified from the autopsy database. An exhaustive search of other available data sources was undertaken to exclude exposure to silica dust in the gold mining industry.

Results: Eighty-five of 3863 (2.2%) platinum mine workers employed for more than a year had silicosis at autopsy; an additional 490 (12.7%) had fibrotic nodules in the lymph nodes. After reviewing all data sources, five mine workers with silicosis and 25 with fibrotic nodules in the lymph nodes fulfilled the study inclusion criteria.

Conclusions: This case series supports the suggestion that there is a risk of silica exposure in platinum mine workers, a hypothesis supported by the few silica dust measurements taken in the platinum mines. The mining companies should be cognisant of this risk. The recording of comprehensive work histories and the routine measurement of silica dust levels should be enforced to enable risk of disease to be quantified in future studies.