Fifteen years after the National Institute for Occupational Safety and Health (NIOSH) issued an in-depth report on coal miner morbidity and mortality, NIOSH now finds that the prevalence of pulmonary diseases is rising.
In 1995, an extensive investigation by NIOSH found that serious lung diseases, primarily pneumoconiosis (CWP) and chronic obstructive pulmonary disease (COPD), were caused by exposure to coal dust and crystalline silica dust.
At that time NIOSH said it drew its conclusions from a wide range of research encompassing epidemiology; medical surveillance; laboratory-based toxicology, biochemistry, physiology, and pathology; exposure assessment; disease prevention approaches; and methods development.
The objective of the more recent work was to update the older material in light of intervening research.
NIOSH found that after a long period of declining CWP prevalence, recent surveillance data indicate that the prevalence is rising.
Also, the research indicates that coal miners are developing severe CWP at relatively young ages (under 50 years). These individuals would have been employed all of their working lives in environmental conditions mandated by the 1969 Coal Mine Health and Safety Act.
Other conclusions are that the increase in CWP occurrence appears to be concentrated in hot spots of disease mostly in the central Appalachian region of southern West Virginia, eastern Kentucky, and western Virginia.
“The cause of this resurgence in disease is likely multifactorial,” according to the NIOSH report. “In this, excess exposure to crystalline silica and the mining of higher rank coal are very plausible explanations. Excess exposure to coal mine dust, both in intensity and duration (longer working hours), may be a contributing factor. A major underlying problem may be achieving sufficient dust control in small coal mines.”
The researchers note that the shift to mining thinner coal seams and those with more rock intrusions will increase the likelihood of potential exposure to crystalline silica and associated increased risk of silicosis. Reduction of the risk would require establishing a separate compliance standard to provide an effective limit to exposure to crystalline silica dust, states NIOSH.
NIOSH’s report is available here.