Coal Workers’ Lung Diseases
Coal miners are at risk for developing several distinct clinical illnesses in relation to their occupational exposures. Historically, some names applied to these conditions were miners’ asthma, phthisis, anthracosis, and in Scotland, miners’ black lung. It was recognized early that these afflictions were related to the occupation of mining; however, it was not until the development of specialized techniques such as chest radiography, pulmonary function testing, the discovery of the tubercle bacillus, and sophisticated histologic examination of tissue that respiratory diseases affecting miners could be separated and defined. Recent advances in the understanding of respiratory health issues in coal miners have focused on the spectrum of disease caused by inhalation of coal mine dust, termed coal mine dust lung disease (CMDLD).1
CMDLD includes the classic occupational interstitial lung diseases, such as coal worker’s pneumoconiosis (CWP), silicosis, and mixed dust pneumoconiosis, but also includes the more recently described entity labeled dust-related diffuse fibrosis (DDF).1 CMDLD is a preventable occupational disease that results from inhalation of coal mine dust into the lungs leading to parenchymal and airway damage, not only from the foreign material itself but also the tissue’s reaction to the dust.1,2 This disease process was identified as early as the 1800s, but became much more prevalent as coal production increased during the industrial revolution. Unfortunately, disability from coal mine dust exposure went mostly unrecognized by medical authorities in the United States through the first part of the 20th century. Congress finally passed comprehensive legislation with the Federal Coal Mine Health and Safety Act of 1969. This Act went above and beyond previous legislation by providing for the first mandatory standards for working conditions in US mines, a system for enforcement, and ongoing monitoring of miner health, as well as a mechanism for seeking financial compensation for coal miners who could demonstrate total disability arising from their dust exposure (aka “black lung”).3
Since the time of this landmark legislation further acts by Congress and enforcement agencies have improved miners’ working conditions, which now fall under the purview of the Mine Safety and Health Administration (MSHA). Much of our improved understanding of the nature and extent of lung disease associated with mining coal in the United States over the past half century comes from the large number of studies performed by the National Institute for Occupational Safety and Health (NIOSH). Despite increased understanding of CWP and reports of stable or improved dust levels in mines, dust-related respiratory disease remains a significant burden. Most worrisome are recent data suggesting that contemporary dust exposure is leading to rapidly progressive pneumoconiosis particularly in young miners, with a significant impact on pulmonary function and premature death.4
Coal is not a pure mineral. It is a spectrum of carbonaceous rocks derived from the accumulation of vegetation sedimented under swampy conditions ...