Article Text
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.
- coal mining
- silicosis
- respiratory system
- occupational health
- miners
Data availability statement
The compliance coal mine dust samples are publicly available directly from the US Mine Safety and Health Administration website. Slides of lung tissue specimens were obtained from a third party and are not publicly available.
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Data availability statement
The compliance coal mine dust samples are publicly available directly from the US Mine Safety and Health Administration website. Slides of lung tissue specimens were obtained from a third party and are not publicly available.
Footnotes
Presented at Part of the data in this manuscript were previously presented in the form of an abstract at the American Thoracic Society International Conference in Philadelphia, PA, USA on 20 May 2013.
Contributors LHTG and RAC are the guarantors of the content of the manuscript, including the data and analysis. All authors contributed to the study conception, study design and data analysis and interpretation. The first draft of the manuscript was written by LHTG. All authors commented on subsequent versions of the manuscript and approved the final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests LHTG and RAC report preparing independent medical reviews for individuals with occupational respiratory disease.
Provenance and peer review Not commissioned; externally peer reviewed.