The negative health and environmental impacts of our nation’s continued reliance on coal as a fuel source for power plants appropriately receives significant attention in the media and in public policy debates. However, the health consequences for those working in underground coal mines have received much less attention. A recent letter to the editor in a medical journal from researchers with the National Institute of Occupational Safety and Health (NIOSH) and an article in the Louisville Courier-Journal will hopefully shine a brighter light and raise the profile of this national tragedy.

For the past 40 years, NIOSH has conducted surveys and monitored trends in the prevalence of coal miners' pneumoconiosis (also known as black lung disease), including progressive massive fibrosis (PMF), the worst form of the disease. PMF is an advanced, debilitating, and lethal form of black lung with no cure and limited treatment options. NIOSH researchers note while the prevalence of this devastating disease in long-term underground miners had essentially been eliminated in the late 1990s, by 2012 it had rebounded to a level ten times higher than those 15 years earlier, to levels not seen since the early 1970s.

So what’s behind the stunning increase in this severe form of black lung disease? The NIOSH researchers note that “excessive inhalation of coal mine dust is the sole cause of PMF in working coal miners, so this increase can only be the result of overexposures and/or increased toxicity stemming from changes in dust composition.” They go on to conclude that “despite readily available dust control technology and best practices guidance, recent findings suggest dust exposures have not been adequately controlled and that a substantial portion of U.S. coal miners continue to develop PMF.”

Corporate malfeasance and a lack of enforcement by the Mine Safety and Health Administration (MSHA) may also be factors in the increase in PMF and other mining-related diseases. Miner health advocates suggest that mine operators are placing coal dust monitors in areas where levels are substantially lower than the much higher and illegal levels that miners are actually exposed to. This allows mining companies to report much lower mine dust levels to MSHA, resulting in a lack of MSHA enforcement.

Last April, MSHA adopted new limits on acceptable levels of coal dust exposure. The agency cut the level set more than 40 years earlier by 25 percent, from two milligrams of dust per cubic meter of air (mg/m³) to 1.5. While an improvement over the previous standard, MSHA had originally proposed a 50 percent cut in allowable exposures, which would have set the level at 1 mg/m³ – a level originally recommended by NIOSH in 1995.

What was behind the decision to adopt the less stringent exposure level? Politics. With the Obama administration already taking substantial heat from the mining industry and their proxies in Congress over proposals to limit carbon dioxide emissions from new and current power plants (limits that would significantly impact the use of coal as a fuel source), MSHA compromised on the coal dust standard. The agency's own analysis found that adopting the compromise standard would still result in as many as 197 cases of PMF and 246 cases of severe emphysema per 1,000 miners over a 45-year work period in jobs exposed to the highest coal dust levels.

MSHA’s revised coal dust exposure limit isn’t scheduled to take effect until August 2016, which means another two years in which exposures to the current unhealthy levels of coal dust will be legally acceptable. With respect to the 154 PMF cases in miners documented by NIOSH between 1998 and 2012, the authors note in their letter that “each of these cases is a tragedy and represents a failure among all those responsible for preventing this severe disease.”