Year of Publication



Public Health

Degree Name

Master of Public Health (M.P.H.)

Committee Chair

Dr. Wayne Sanderson

Committee Member

Dr. Steven Browning

Committee Member

Dr. Nancy Johnson


I. Specific Aims:

i. Review potential factors contributing to the resurgence of coal workers’ pneumoconiosis (CWP) in Appalachia and analyze the Mine Safety and Health Administration (MSHA) Complete Quartz dataset for potential contributors of underground (UG) coal miner exposure to silica and coal dust.


  1. i. To provide evidence of an association between silica and coal dust exposure and various UG coal miner occupations and mine locations.
  2. ii. Explore changes over time in UG coal miner silica exposure, dust exposure, and silica concentration in samples collected.
  3. iii. Determine if UG coal miners have experienced an increase in exposure to silica based on MSHA silica and dust samples, and if this can be attributed to the rise in CWP prevalence in Appalachia.

Background: The practice of coal mining places miners at risk for developing (CWP) due to exposure to respirable coal and crystalline silica particles (known as silica henceforth).

While the prevalence had been on the decline prior to the late 1990s, in the recent decades cases of CWP and progressive massive fibrosis (PMF) have increased significantly, particularly in Appalachia.

Methods: Data from the MSHA Complete Quartz Dataset was used to analyze silica exposure amongst UG coal miners across UG miner occupation and geographic location.

Results: Occupations associated with the coalface were found to have amongst the largest silica exceedance fractions (MINER=34.83%, LONGWALL-MINER=33.72%, ROOFBOLTER=28.43%) as well as dust exceedance fractions (LONGWALLMINER=32.28%, AUGER=31.21%, COALPREP=28.1%). When analyzing the data with respect to mine location, mines located within the Appalachia region had amongst the largest GM exposure to silica (TN=30.08 µg/m3, MD=25.97 µg/m3, WV=25.88 µg/m3) compared to non- Appalachian states (UT=12.59 µg/m3, NM= 14.43 µg/m3, CO=14.97 µg/m3). Decreases in geometric mean (GM) silica and dust concentrations were also found. By 2016, GM silica concentration had decreased 45.52% while GM dust concentrations decreased 61.19% over the 27 years samples were collected. However, GM silica concentration had increased 41.8%, indicating that while dust control measures have been effective in decreasing exposure, control measures have not successfully controlled for silica exposure.

Conclusion: There are plausible associations between UG coal mining silica/dust concentration samples and miner occupation, mine location, and sample year. Geometric mean silica and dust concentrations indicate varying degrees of exposure amongst UG coal mining occupations and percentages of samples exceeding various occupational exposure levels (OELs) provide evidence of historical high exposure. Significant differences between state means shows potential evidence that further investigation into the geology of parts of the country, as mines in the eastern US have silica and dust concentrations that are significantly different and greater than mines in the western US. Analysis of concentration and sample year show a decline in GM and exceedance fractions of both silica and dust concentrations. However, an analysis of silica percentages in dust samples over the same period indicates that while dust concentrations have decreased, miners are being exposed

to dust levels with higher concentrations of silica, emphasizing the need for more stringent monitoring of silica concentrations in UG mines.

Included in

Public Health Commons