Respirable coal mine dust in underground mines, United States, 1982‐2017

Abstract

Background Exposure to respirable coal mine dust can cause pneumoconiosis, an irreversible lung disease that can be debilitating. The mass concentration and quartz mass percent of respirable coal mine dust samples (annually, by occupation, by geographic region) from surface coal mines and surface facilities at U.S. underground mines during 1982‐2017 were summarized. Methods Mine Safety and Health Administration (MSHA) collected and analyzed data for respirable dust and a subset of the samples were analyzed for quartz content. We calculated the respirable dust and quartz concentration geometric mean, arithmetic mean, and percent of samples exceeding the respirable dust permissible exposure limit (PEL) of 2.0 mg/m3, and the average percent of quartz content in samples. Results The geometric mean for 288 705 respirable dust samples was 0.17 mg/m3 with 1.6% of the samples exceeding the 2.0 mg/m3 PEL. Occupation‐specific geometric means for respirable dust in active mining areas were highest among drillers. The geometric mean for respirable dust was higher in central Appalachia compared to the rest of the U.S. The geometric mean for respirable quartz including 54 040 samples was 0.02 mg/m3 with 15.3% of these samples exceeding the applicable standard (PEL or reduced PEL). Occupation‐specific geometric means for respirable quartz were highest among drillers. Conclusion Higher concentrations of respirable dust or quartz in specific coal mining occupations, notably drilling occupations, and in certain U.S. regions, underscores the need for continued surveillance to identify workers at higher risk for pneumoconiosis.

Respirable coal mine dust at surface mines, United States, 1982–2017

“…The mean percent quartz was significantly higher in central Appalachia (7.5%) than the rest of the United States (7.0%). Importantly, both were higher than the underground mine samples mean percent quartz (6.7%) for central Appalachia and the rest of the United States (3.9%) …”

“…Data from MSHA Districts 4, 5, and 12 were combined (central Appalachia) and compared with MSHA Districts 2 to 3 and 7 to 10 combined (rest of the United States). Detailed methods and maps are available in a recent publication …”

“…To better inform our understanding of the pneumoconiosis trends in the U.S., we recently summarized the annual mass concentration and quartz mass concentration of respirable dust samples collected during 1982–2017 for compliance purposes in underground coal mines by Mine Safety and Health Administration (MSHA) inspectors . The primary findings demonstrated that the mean percent quartz content in Appalachian underground coal mines consistently exceeded 5% and nearly one‐third of U.S. coal mines had a least one section placed on a reduced standard.…”

Current Review of Pneumoconiosis Among US Coal Miners

“…According to federal data, operator compliance with dust standards has been high for decades, with > 99% compliance since the PEL was reduced. [29][30][31] The preamble to the 2014 MSHA rule highlighted the agency's intent to conduct a retrospective study, beginning in February 2017, "to assess the impact of the Dust rule on lowering coal miners' exposures to respirable coal mine dust to improve miners' health." Pneumoconiosis is usually a disease of long latency, and conducting an adequate assessment of the effectiveness of the rule in improving health outcomes for miners will require many years of observation and study.…”

Pneumoconiosis progression patterns in US coal miner participants of a job transfer programme designed to prevent progression of disease

“…The prevalence and severity of pneumoconiosis in US coal miners has markedly increased in the last 20 years 1 2. Changes in the composition of the dust, including excessive exposure to crystalline silica, have been implicated in playing a role in the observed resurgence of disease and the increase in the most severe forms including progressive massive fibrosis (PMF) 3–6. Federal standards, first enacted in 1969, established primary and secondary prevention programmes to protect underground coal miners from material respiratory impairment resulting from excessive exposure to coal mine dust 7.…”