CDC Issues Alert on Resurgence of Progressive Massive Fibrosis in Coal Miners

A rise in the most severe form of pneumoconiosis (black lung disease), progressive massive fibrosis (PMF), a potentially lethal disease—has been reported by the CDC.

The prevalence of PMF fell sharply after the implementation of the Coal Mine Health and Safety Act of 1969, which established dusts limits for US coal mines and created the National Institute for Occupational Safety and Health (NIOSH), and reached historic lows in the 1990s. Since then, a resurgence of PMF has occurred in central Appalachia, with a new report of a cluster of 60 cases of PMF identified in former and current coal miners at a single eastern Kentucky radiologist’s practice from January 2015 to August 2016.

The cluster was not discovered through the national Coal Workers’ Health Surveillance Program, which is not surprising since participation rates in the national program among Kentucky coal miners is historically low, with only 17% of the state’s coal miners participating in the program during 2011 and 2016.

The radiologist who contacted NIOSH to report the sharp increase during the past 2 years in the number of PMF cases among patients who were coal miners requested assistance in conducting an investigation and developing and implementing interventions to reduce prevalence of the disease in the community. Sixty male patients who were active or former coal miners had radiographic findings consistent with PMF, including 49 whose radiographs were taken during 2016. The mean age of the patients was 60.3 years; mean coal mining tenure was 29.2 years. All 60 patients had radiographic evidence of pneumoconiosis. Twenty-six reported being roof bolters (installing the bolts that support the roof of an underground mine) for most of their careers and 20 reported being operators of continuous miners (machines that produce a constant flow of coal or other solid material from the working face of the mine).

“The factor or combination of factors that led to this increase in cases of PMF in eastern Kentucky and whether there are more unrecognized cases in neighboring coal mining regions are unknown,” the CDC stated. Because PMF takes years to manifest, the specific exposures or mining practices that led to these cases are also unknown. “New or modified mining practices in the region might be causing hazardous dust exposures,” the report noted.

Detailed occupational histories identified “slope mining” (in which teams of miners operate continuous miner machines, designed to cut coal and other soft rock and cut shafts through hundreds of feet of sandstone to reach underground coal seams) as a potential exposure in eastern Kentucky. The sandstone formation underlying that area is more than 90% quartz, and dust generated during slope cutting could expose miners to hazardous dust containing high concentrations of respirable crystalline silica. Operating a continuous miner machine has typically been considered position not associated with higher silica dust exposures. However, the use of a continuous miner machine during shaft cutting or thin seam coal mining requires cutting through rock, and creates the potential for respirable silica exposures, explaining why working as a continuous miner operator could pose an increased risk for PMF.

Other industry trends might have led more miners to seek radiographs from the reporting physician—namely, the steep decline in coal miner employment and production during recent years, which may have led miners to feel that future coal-related employment is unlikely and thus dropping previous barriers to health-seeking behaviors. Because the earlier stages of coal workers’ pneumoconiosis can be associated with few symptoms, and because coal mining jobs have historically been among the best-paying in the region, some miners might have chosen to not seek radiographs or during the earlier stages of their career to avoid threatening their ability to continue working in the industry.

“The findings in this report serve as a reminder that more than 45 years after the Coal Act’s passage, one of its core objectives has not been achieved,” the CDC report noted. In the coming years, NIOSH will focus active surveillance measures on miners in central Appalachia and will continue to work with miners, mine operators, regulatory and disability compensation agencies, and others to better characterize the scope of the problem, expand educational outreach to miners to increase their awareness of the right to confidential medical screening, and prevent overexposures to coal mine dust.

Reference

Blackley DJ, Crum JB, Halldin CN, Storey E, Laney AS. Resurgence of progressive massive fibrosis in coal miners—Eastern Kentucky, 2016. MMWR. 2018;65(49). December 16, 2016.