I’m playing catch-up on a medical study that is very important to understanding the risks of black lung that surface miners face.
In the January 2015 issue of the Journal of Occupational and Environmental Medicine, a group of interdisciplinary researchers published a study titled, “Debilitating Lung Disease Among Surface Coal Miners With No Underground Mining Tenure.”
The study, which is embedded below, focused on surface miners who did not work in underground mines, yet had evidence of complicated coal workers’ pneumoconiosis—also known as progressive massive fibrosis (“PMF”).
The study is important because on the one hand, surface miners are a huge part of the mining workforce, making up 44.3% of miners in 2012, while on the other hand, surface miners are not treated equally with underground miners in the legal system and have been excluded from many surveillance efforts. For example, until 2014, surface miners were not eligible for Part 90 status if they had black lung and wanted to reduce their dust exposure while continuing to work at the mine. And if they are no longer able to work and seek federal black lung benefits, surface miners still have to meet an additional burden of proving that the dust conditions they worked in were similar to those in underground coal mines.
The study looks at survey data from the 2010 and 2011 NIOSH Enhanced Coal Workers’ Health Surveillance Program. 2328 surface miners with at least one year of tenure were x-rayed for free. Of these 2% (~47 miners) had coal workers’ pneumoconiosis. Of the 47, 12 had the severe form of the disease, PMF. While 12 miners out of 2328 is a relatively low number, this results show that more than one out of four surface miners who have black lung, have the severe form: PMF.
The study then sought more information from these 12 miners to better understand their work and health histories. Of the 12, 3 had some underground mining history and 1 had evidence of sarcoidosis and were excluded from the study. The researchers spoke to three of the miners or their next-of-kin and were able to review medical records (including pathology slides) for two of the miners.
The study gives sketches of these miners and their backgrounds. All were drillers or blasters and reported being exposed to substantial amounts of dust. For example, here are two miners stories which sound very similar to the stories that people involved with the black lung benefits system often hear from surface miners:
Miner 6 reported 9 years of work as a contract blaster at surface coal mines, and 1 year as a haul truck operator, driller, and maintenance worker for a coal company before his survey chest radiograph showing PMF. As a contract blaster, he reported many days on which he worked for several hours in dust clouds generated by drilling rigs. He asserted that the contract employer did not provide either a respiratory protection program or training about dust hazards, and he did not recall any personal dust sampling. In contrast, during the 1 year he worked as a mining company employee, Miner 6 described regular use of dust collectors and air-conditioned cabs, and he perceived lower dust exposure compared with his years of contract work. The mining company had also performed dust measurements to assess compliance with regulations. Miner 6 did report exposure to intermittent dust clouds during the use of compressed air on equipment maintenance and blowing dust out of filters.
Miner 8 described variable but often very dusty working conditions. Many of the drills he operated did not have effective dust collectors. Frequently, drills did not have cabs; a drill designed for wet drilling (not equipped with a cab or dry dust collector) was regularly operated without water. On drills with cabs, the air-conditioning system was often in poor operating condition, and dust would recirculate inside the cab. On early model drills, it was frequently necessary to open cab doors to avoid the dust and extreme heat emitted by the drill machinery. At times, to avoid extreme heat or dust, he left the cab while drilling. To document his assertions, he provided photographs illustrating the working conditions he experienced at surface mines throughout his career. These showed workers exposed to clouds of dust at the drill site (Fig. 4 representative examples). Miner 8 reported that personal dust sampling was done a few times per year when federal mine inspectors were on the job site, but he denied
existence of a respiratory protection program or of being informed of dust sampling results.
At the age of 56 years, Miner 8 began having shortness of breath and cough with moderate physical activity. Previously, he had been physically active and without symptoms, and had never smoked. After receiving a report of PMF on his survey radiograph, he sought medical care. His lung function was found to be significantly reduced and exhibited a restrictive pattern: forced expiratory volume in 1 second was 75%, forced vital capacity was 69%, and total lung capacity was 62% of the predicted reference values. Cardiopulmonary exercise testing revealed a low partial pressure of oxygen (pO2) at peak exercise and no evidence of any cardiac limitation. His physician diagnosed him with severe silicosis with PMF and advised him to leave mining.
The images provided by Miner 8 show that extremely dusty condition that surface miners may have to work in.
The progression of disease shown in Miner 8’s chest x-rays demonstrates PMF.
The study includes other interesting information about the role of silica exposure for these miners’ lung problems as well as an explanation for why cancer does not explain the x-ray findings.
The authors concluded that these miners severe lung diseases were the result of inadequate dust control and education.
Even though all of the miners in this study worked their entire careers under the provisions of the 1969 Coal Act, study results show that severe forms of pneumoconiosis continue to occur in miners whose occupational exposure occurred exclusively through surface coal mining work. Supplemental information provided by some participants indicated that dust controls were often insufficient at their worksites. Given that surface coal miners make up a substantial portion (44%) of the coal mining workforce, the case series results and ongoing silica overexposures documented by MSHA sampling highlight the need to reduce respirable dust exposures at surface mining operations and demonstrate the need for including surface miners in routine respiratory health surveillance.
The study has important implications for surface miners with respiratory disabilities who are seeking black lung benefits. The study makes clear that severe black lung affects miners who never set foot in an underground mine and that miners with as little as 10 years of exposure working on a surface mine can get severe black lung.
The study’s authors were: Cara N. Halldin, PhD, William R. Reed, PhD, Gerald J. Joy, MS, Jay F. Colinet, MS, James P. Rider, BS, Edward L. Petsonk, MD, Jerrold L. Abraham, MD, Anita L. Wolfe, BA, Eileen Storey, MD, and A. Scott Laney, PhD.