WASHINGTON – Black lung disease cases in coal miners have been increasing since 2000 for uncertain reasons. A new report by the National Academies of Sciences, Engineering, and Medicine says that even though mine operators today are complying with regulatory requirements for monitoring conditions that affect miner health, these approaches may not guarantee that exposures will be controlled adequately or that future disease rates will decline. A fundamental shift is needed in the way mine operators approach exposure control to continue progress toward eliminating coal mine dust-related lung diseases. The report recommends a number of actions for the National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) that range from improving current monitoring technologies to building research activities that address the gaps in knowledge.
Coal mine dust-related lung diseases are a complex problem that continues to affect coal miners in the U.S. Though black lung disease rates declined in the latter decades of the 20th century following the regulatory requirements in 1969, an unexpected increase in the cases has been observed in various geographic areas in central Appalachia since 2000. Historically, the primary focus of monitoring and sampling of respirable coal mine dust – comprising airborne particles in underground mines that can be inhaled by miners and deposited in the distal airways and gas-exchange region of the lung – has been based on federal regulation compliance, which has reduced but not eliminated such diseases. In 2014, MSHA issued a rule that lowered allowable exposure limits for respirable coal mine dust and required the use of different monitoring technology and sampling protocols for mine workers’ dust exposure.
Subsequently, the Academies were asked by Congress to assess monitoring and sampling approaches to inform the decision-making of underground coal mine operators regarding the control of respirable coal mine dust and mine workers’ exposure to it, as mandated in the Consolidated Appropriations Act, 2016.
“There is an urgent need for monitoring and sampling strategies that enable continued, actual progress to be made toward the elimination of diseases associated with coal mine dust exposure,” said Thure Cerling, Distinguished Professor of Geology and Geophysics and Distinguished Professor of Biology at the University of Utah and chair of the committee that conducted the study and wrote the report.
Receiving reliable information on coal mine dust is crucial for predicting, reducing, and preventing disease risks, the report finds. A focus on reducing exposures during miners’ entire working life is important because black lung disease and silicosis occur over a long period of time and the level of disease risk is related to the total amount of dust exposure.
While no treatment is successful in reversing the lung diseases caused by exposure to respirable coal mine dust, better miner participation in the voluntary medical surveillance system for early disease detection is significant in protecting the miner’s health, says the report. The report notes that lack of participation from workers in medical surveillance impacts the efficacy for assessment efforts to reduce exposure. NIOSH and MSHA should identify factors that act as disincentives for participation in the voluntary medical surveillance and address them, the report continues. Data from the medical surveillance programs should be linked directly with exposure monitoring programs and integrate health-related data on active and retired miners. Comprehensive occupational histories containing details such as specific mine employment, duration of work at the coal face, and use of respiratory protection should be included.
MSHA’s 2014 dust rule requires the use of a continuous personal dust monitor (CPDM), an important, technological advancement that checks the mass concentration of dust in near real time, the report says. Previous monitoring devices required several days for the monitoring data to be available to the mine operator and the workforce, creating a delay in decisions on necessary changes to better control dust generation or dust exposure at a location. However, only a fraction of miners are required to use CPDM and an individual worker may not be representative of the dust exposure to others not wearing the device. The report recommends conducting studies to evaluate the exposures of all mine workers to ensure that the approach reliably results in mitigating high exposures for all miners.
The report also highlights the importance of training miners to use these monitors properly as well as educating them about risks of coal mine dust diseases, hazards of silica and rock dust, and the miners’ right to file a complaint without fear of retaliation, among other factors. At the same time, the committee also recommended improving the monitors by reducing their weight and cost.
Crystalline silica is a highly relevant constituent in respirable coal mine dust with regard to lung disease in miners. Given the health hazards posed by silica, the report calls for NIOSH to develop a real-time crystalline silica monitor. As an interim measure, NIOSH should continue its efforts to develop monitors that provide exposure readings by the end of a miner’s shift.
To inform exposure control efforts, the committee said NIOSH and other organizations such as the National Mining Association should conduct a comprehensive investigation to identify key challenges mine operators face in implementing a beyond-compliance approach to monitoring.
The committee also identified important information gaps regarding monitoring and sampling protocols for controlling miners’ exposure to coal mine dust. The report notes that research and development efforts are needed for better understanding of relationships between miners’ exposures and disease, including studying effects of changes in mining methods, improving monitoring approaches, and increasing participation in medical surveillance programs. A comprehensive assessment of respirable coal mine dust particle characteristics will help target future studies about exposure because the health hazards can vary.
NIOSH, MSHA, and other organizations should set priorities and develop a strategy for addressing the recommendations outlined in the report. Federal, academic, and coal mine industry researchers should seek opportunities for conducting collaborative research and development activities, the report says.
The committee was asked not to recommend changes to the requirements of MSHA’s final rule for lowering miners’ exposure to respirable coal mine dust, as the development of those requirements involves considerations beyond the scientific and technical focus of this study.
The study was sponsored by NIOSH. The National Academies of Sciences, Engineering, and Medicine are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. The National Academies operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln. For more information, visit http://national-academies.org.