What component of coal causes coal workers' pneumoconiosis?

OBJECTIVE To evaluate the component of coal responsible for coal workers' pneumoconiosis (CWP). METHODS A literature search of PubMED was conducted to address studies that have evaluated the risk of CWP based on the components of coal. RESULTS The risk of CWP (CWP) depends on the concentration and duration of exposure to coal dust. Epidemiology studies have shown inverse links between CWP and quartz content. Coal from the USA and Germany has demonstrated links between iron content and CWP; these same studies indicate virtually no role for quartz. In vitro studies indicate strong mechanistic links between iron content in coal and reactive oxygen species, which play a major role in the inflammatory response associated with CWP. CONCLUSIONS The active agent within coal appears to be iron, not quartz. By identifying components of coal before mining activities, the risk of developing CWP may be reduced.