Abstract

Objectives
In 2010, 29 coal miners died due to an explosion at the Upper Big Branch (UBB) mine in West Virginia, USA. Autopsy examinations of 24 individuals with evaluable lung tissue identified 17 considered to have coal workers’ pneumoconiosis (CWP). The objectives of this study were to characterise histopathological findings of lung tissue from a sample of UBB fatalities and better understand the respirable dust concentrations experienced by these miners at UBB relative to other US coal mines.

Methods
Occupational pulmonary pathologists evaluated lung tissue specimens from UBB fatalities for the presence of features of pneumoconiosis. Respirable dust and quartz samples submitted for regulatory compliance from all US underground coal mines prior to the disaster were analysed.

Results
Families of seven UBB fatalities provided consent for the study. Histopathologic evidence of CWP was found in all seven cases. For the USA, central Appalachia and UBB, compliance dust samples showed the geometric mean for respirable dust was 0.468, 0.420 and 0.518 mg/m3, respectively, and respirable quartz concentrations were 0.030, 0.038 and 0.061 mg/m3. After adjusting for quartz concentrations, UBB exceeded the US permissible exposure limit (PEL) for respirable dust in 28% of samples.

Conclusions
Although higher than average respirable dust and quartz levels were observed at UBB, over 200 US underground coal mines had higher dust concentrations than UBB and over 100 exceeded the PEL more frequently. Together with lung histopathological findings among UBB fatalities, these data suggest exposures leading to CWP in the USA are more prevalent than previously understood.

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Comments

Something important can come out of disasters. In 2010 an underground explosion killed 29 coal miners in the USA, their post mortems come as close to a random population sample of miners as it is possible to get. 17/24 had histological evidence of pneumoconiosis, two with less than 5 years exposure. The mine had exposure levels well below many in the USA. It suggests that exposures need to be significantly reduced (or coal mining abandoned to help control global warming).

5/8/2022