Dust Levels in Underground Coal Mines at Historic Low

In the dark, enclosed spaces of coal mines exists a silent killer. This silent killer is also known as respirable coal mine dust.

Respirable coal mine dust is the portion of airborne dust in coal mines capable of entering the gas-exchange regions of the lungs if inhaled. Though it is, by convention, a particle-size-selective fraction of the total airborne dust in a mine, it has killed more than 76,000 miners since 1968, according to NIOSH estimates.

Respirable coal mine dust exposure can lead to several health risks that can span a lifetime. Such exposures are associated with the development of occupational respiratory diseases, including simple coal workers’ pneumoconiosis (CWP), progressive massive fibrosis (PMF), and chronic obstructive pulmonary disease (COPD), all of which are often collectively referred to as black lung.

“Feels like I’ve got a heavy wet sack on each lung.”

For the coal miners who fall victim to black lung, life is never the same.

A coal miner named Mark McCowan who lives in Virginia and was diagnosed with black lung at age 40 told NPR, who recently did a series on mine safety, “Now it feels like I’ve got a heavy wet sack on each lung… Breathing has become a conscious effort. It seems like I give up a little bit of my world each day, that it gets smaller and smaller.”


Chester Fike is another coal miner who was diagnosed with black lung. He was only in his 30s when the terrible disease began to take hold. Eventually he was so incapacitated that a simple walk with his family was impossible. Unfortunately, even after a double lung transplant, he passed away at the young age of 60.

In an effort to spare other coal miners a fate similar to Mark and Chester, the Mine Safety and Health Administration (MSHA) launched its “End Black Lung” campaign in 2009 and published a final rule, which took effect August 2014 and lowers miners’ exposure to respirable coal mine dust in all underground and surface coal mines.

The final rule strives to do the following:

  • reduces the overall dust standard from 2.0 to 1.5 milligrams per cubic meter of air and cuts in half the standard from 1.0 to 0.5 for certain mine entries and miners with pneumoconiosis;
  • requires immediate action when dust levels are high instead of allowing days or weeks of miners’ exposure to unhealthy dust;
  • requires more frequent sampling of areas known to have relatively high dust levels, such as those closest to the production area;
  • changes the method of averaging dust samples, which previously allowed miners on some shifts to be exposed to levels above the standard;
  • requires sampling for the full shift a miner works to ensure protection for all working hours, rather than stopping measurement after 8 hours, as under the previous requirement;
  • requires that, for MSHA-collected samples, MSHA will issue a citation for any single, full-shift sample at or exceeding the citation level;
  • requires dust samples to be taken when mines are operating at 80 percent of production, as opposed to the previous 50 percent requirement, so that samples are more representative of actual working conditions;
  • requires mine operators to conduct thorough on-shift examinations of dust controls and verify controls with written certification; and
  • improves medical surveillance of miners.

Results show the new dust rule is working.

According to a recent new release from MSHA, results show the new dust rule and the “End Black Lung” campaign are working and miners should be breathing cleaner air at coal mines.

Since MSHA introduced the “End Black Lung” campaign, the yearly average of respirable dust levels in underground coal mines has fallen every year. In 2014, dust levels reached the lowest level ever recorded.

From August 1, 2014 through December 31, 2014, more than 23,600 dust samples were collected. Results show that about 99 percent of samples are in compliance.

Furthermore, of the dust samples collected, 252 (or 1.4 percent) of them even exceeded compliance levels.

More still needs to be done.

Though results look promising, there are still many things that need to be done. Miners, including young miners, continue to be diagnosed with black lung disease, which affects their personal health, their livelihood, and their families.

What do you think would best motivate employers to provide safe working conditions for workers in the mining industry? Tell us your thoughts in the comments below or join our forum conversation.