To the Editor:

For more than 40 years, the National Institute for Occupational Safety and Health (NIOSH) has monitored trends in coal workers’ pneumoconiosis, including progressive massive fibrosis (PMF). PMF is an advanced, debilitating, and lethal form of coal workers’ pneumoconiosis with limited, primarily palliative treatment options and no cure. As part of ongoing surveillance efforts, NIOSH administers the Coal Workers’ Health Surveillance Program (CWHSP), which offers underground coal miners periodic chest radiographs and confidentially informs them of their pneumoconiosis status (1). Just 15 years ago, PMF was virtually eradicated, with a prevalence of 0.08% among all CWHSP participants and 0.33% among active underground miners with at least 25 years of mining tenure. Since that time, the national prevalence of PMF identified through the CWHSP has increased; the rate of increase in the central Appalachian states of Kentucky, Virginia, and West Virginia has been especially pronounced (Figure 1). Excessive inhalation of coal mine dust is the sole cause of PMF in working coal miners, so this increase can only be the result of overexposures and/or increased toxicity stemming from changes in dust composition (2). During 1998 to 2012, NIOSH identified 154 cases of PMF among CWHSP participants, 125 of whom were long-tenured underground coal miners in central Appalachia. In 2012, the prevalence of PMF in this group of working miners reached 3.23% (5-year moving average), the highest level since the early 1970s. At the same time, NIOSH documented cases of PMF among surface coal miners with little or no underground mining tenure (3).

Figure 1. Prevalence of progressive massive fibrosis among working underground coal miners with 25 or more years of underground mining tenure (1974–2012) in Kentucky, Virginia, and West Virginia, according to the Coal Workers’ Health Surveillance Program. Data are 5-year moving average (e.g., data plotted for 1974 = $\frac{{{\displaystyle \sum }}^{\text{}}[PM{F}_{1970}+PM{F}_{1971}+PM{F}_{1972}+PM{F}_{1973}+PM{F}_{1974}]}{{{\displaystyle \sum }}^{\text{}}Participant{s}_{1970-1974}}$; surveillance is conducted on a 5-year national cycle).

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Each of these cases is a tragedy and represents a failure among all those responsible for preventing this severe disease. This year marks the 45th anniversary of the Federal Coal Mine Health and Safety Act. In that legislation, Congress enacted enforceable dust standards to reduce the incidence of coal workers’ pneumoconiosis and eliminate PMF among underground coal miners (4). Despite readily available dust control technology and best practices guidance (5), recent findings suggest dust exposures have not been adequately controlled and that a substantial portion of U.S. coal miners continue to develop PMF. On August 1, 2014, NIOSH issued an interim final rule modifying existing regulations to include surface coal miners in the CWHSP (6). In addition, the interim final rule expands medical surveillance beyond occupational history and chest radiography to include respiratory symptom assessment and spirometry testing for the recognition of undiagnosed chronic obstructive pulmonary disease among all working coal miners. We believe that expanded medical surveillance is an important part of ensuring success in efforts to protect U.S. coal miners from this deadly but entirely preventable disease.

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