INCREASED PREVALENCE OF COAL WORKERS’ PNEUMOCONIOSIS: WHAT SHOULD WE DO NOW?

Recent epidemiological studies have demonstrated that prevalence of coal workers’ pneumoconiosis (CWP) has increased in Eastern Appalachian coals, such as Virginia, West Virginia, and Kentucky, but not in Western coal mine regions, such as Utah and Colorado. We and others have shown that bioavailable iron (BAI) and quartz in the Appalachian coals are likely causative compounds that lead to CWP development. BAI and quartz induce oxidative stress, inflammation, and epithelial mesenchymal transition, molecular events driving epithelial phenotype into fibroblast phenotype in the lung. Yet, both are present in the Eastern and Western coals alike. Why would these two compounds cause a health problem to the coal miners in the Eastern but not to those in the Western coal mines in the U.S.? Instead of further investigating mechanisms by which BAI and quartz cause CWP, we have taken a more pragmatic approach and investigated what compound(s) in the mixed coal dust inhibits the toxicities of BAI and quartz and, thus, prevents CWP from rising in the Western coal workers. In the Western coals, we have found that calcite (CaCO₃) prevents iron from becoming bioavailable and limits endogenous iron to interact with quartz. By adding calcite into the Appalachian coals, we have found that the addition of calcite resulted in reduced toxicity of the coal dust. Based on these data, we propose a novel strategy to use calcite to reduce coal dust toxicity rather than to reduce dust concentration to prevent CWP in the Appalachian coal field. This strategy may be more feasible since the conventional dust control technology appears to have approached their maximum capacity, making an even more stringent dust standard impractical. In the presentation, I will discuss various ways to add calcite before or during mining. This work was supported by a grant from the National Institute for Occupational Safety and Health (NIOSH); grant number: 1R01 OH009771.