Characterization of Underground Coal Miners' Exposure to Respirable Coal Mine Dust

Coal Workers' Pneumoconiosis (CWP) is a debilitating lung disease that has plagued the coal mining industry since its inception. Most researchers acknowledge that there has been a significant reduction in the prevalence of CWP since 1970, but there has not been an elimination of this disease. Between 2005 and 2006, the NIOSH Enchanced Coal Workers' Health Surveillance Program (ECWHSP) identified at least eleven new cases of progressive massive fibrosis, with 9% of miners surveyed showing x-ray evidence of pneumoconiosis. These results are especially troubling given that the prevalence of CWP in underground miners has declined significantly for those with over 25 years experience, but the rate of decline is much smaller for those who began mining since the implementation of the respirable coal dust standards between 1969 and 1977.

This study analyzed the Mine Safety and Health Administration (MSHA) inspector respirable coal mine sampling data for underground coal mines between 2005 and 2006. Results show that 3.1% (1253 of 40,239) of samples exceeded the 2.0mg/m3 permissible exposure limit (PEL). When examining the data based on individual mines, one can see that 65% of mines had samples exceeding the PEL, and 20% of samples exceeded the 1.0mg/m3 NIOSH recommended standard (REL). Several occupations were affected by high levels of coal mine dust. Continuous miner operators and roof bolters represented 16% and 20% of the samples exceeding the PEL, respectively. These results have serious implications for future coal mine respirable dust federal policies, and the health of underground coal miners.