Is volcanic ash a pneumoconiosis risk?

Abstract

In vitro studies of the mutagenic, fibrogenic and cytotoxic potential of Mount St Helens volcanic ash, and its likely effect(s) on immunological, antiviral and antibacterial defence mechanisms, have been reported elsewhere^1,2. These studies indicated that the ash has a moderate fibrogenic potential as it was markedly cytolytic in a sheep red blood cell haemolysis assay, had a stimulatory effect on W1-38 fetal lung fibroblasts and increased production of acid hydrolases by ash-exposed alveolar macrophages. We report here that in rats exposed intratracheally to volcanic ash, there was an acute pulmonary inflammatory response, followed by a granulomatous and fibre-tic reaction which persisted until the end of the 6-month study period. We also examined the lungs of two heavily exposed humans and found lesions consistent with a reaction to volcanic ash. Although the ash does not seem to be highly toxic, these results suggest that precautions should be taken to minimize exposure of high-risk individuals.