Coal Tattoo

Black lung disease: Let’s review

With the Obama administration set to release its plan to “End Black Lung” on Thursday, perhaps it’s worth reviewing some of what the science tells us about black lung and how to prevent it …

Luckily, the folks at the National Institute for Occupational Safety and Health recently published a summary of scientific findings about black lung since 1995. It’s available online here, and NIOSH describes it this way:

In 1995 in a major NIOSH review and report of recommendations, entitled Criteria for a Recommended Standard – Occupational Exposure to Respirable Coal Mine Dust. This Current Intelligence Bulletin updates the information on coal mine dust exposures and associated health effects from 1995 to the present. In part, the intent is to determine whether the 1995 recommendations, in this respect, remain valid, and to what extent, if any, modifications or additions are needed to those recommendations. The report does not deal with, nor discuss, issues of sampling and analytical feasibility nor technical feasibility in achieving compliance.

Of course, that 1995 NIOSH report — available here — clearly recommended that MSHA tighten the allowable limit of coal dust in underground mines from 2 milligrams per cubic meter to 1 milligram per cubic meter.

So what does the new NIOSH report say? Well, how about these comments:

— While findings published since 1995 refine or add further to the understanding of the respiratory health effects of coal mine dust described in the NIOSH Criteria … they do not contradict or critically modify the primary conclusions and associated recommendations given there. Rather, the new findings strengthen those conclusions and recommendations.

Even at the lower coal mine dust levels recommended by NIOSH … some incidence of [black lung] would still be expected, especially among miners of higher rank coal.

— … Even at the 1 mg/m3 coal mine dust exposure limit recommended by the CCD, some occupational effect on ventilatory function is expected.

Also important findings, emphasized by the NIOSH document:

— After a long period of declining black lung prevalance, recent federal surveillance data indicate that the prevalence is rising.

— Coal miners are developing severe black lung at relatively young ages.

— There is some indication that the mortality of younger coal miners from black lung is increasing.


— The cause of this resurgence in disease is likely multifactorial; 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 an apparent difficulty of achieving dust control in small coal mines.

— Given that the more productive seams of coal are being mined out, a transition by the industry to mining thinner coal seams and those with more rock intrusions is taking place and will likely accelerate in the future. Concomitant with this is the likelihood of increased potential for exposure to crystalline silica, and associated risks of silicosis, in coal mining.

NIOSH concludes:

In summary, every effort needs to be made to reduce exposures both to respirable coal mine dust and to respirable crystalline silica.