Public Health & Preventive Medicine. Fifteenth Edition, Wallace RB, Kohatsu N, Last JM, eds., New York: The McGraw-Hill Companies, Inc., 2007 Sep; :583-590
Lung disease among underground coal miners has been a recognized occupational hazard since at least the mid-seventeenth century. Miners' black lung, now called coal workers' pneumoconiosis (CWP) was first documented among Scottish coal miners in 1837. Although the disease was thought to be disappearing in Britain at the turn of this century, wider use of chest radiographs following World War I showed pneumoconiosis, similar to silicosis, among coal miners in South Wales. By 1934, British physicians were beginning to accept coal dust as an occupational exposure that could result in disability and death. In 1942, the Committee on Industrial Pulmonary Diseases of the Medical Research Council introduced the term "coal workers' pneumoconiosis." In marked contrast, appreciation of CWP as an occupational disease and public health problem occurred much later in the United States, as did legislation to prevent or compensate CWP and associated respiratory disease. One reason for the relatively late recognition of CWP as a distinct disease entity in the United States was the early emphasis placed on the etiological role of silica in pneumoconiosis. The Hawk's Nest tragedy (1932-1934), in which more than 400 workers died of acute silicosis and tuberculosis after working on the tunnel at Gauley Bridge, West Virginia, reinforced the prevalent theory that silica content was the critical etiological agent in pneumoconiosis. The first systematic study of U.S. coal miners was conducted by the Public Health Service between 1928 and 1931 in the anthracite coal fields in eastern Pennsylvania. Because of the relatively high silica content and similarity to silicosis, the term "anthracosilicosis" was used to describe the pneumoconiosis found among those miners. Of 2711 men studied, 23% were found to be affected. The prevalence of pneumoconiosis was related to the number of years underground, particles per cubic meter, and free silica content of the dust. "Pulmonary infection" was more frequent among miners with higher dust exposure and greater than 15 years underground. Among miners over age 55, pulmonary tuberculosis was as much as 10 times more common than in the general population. Little additional progress was made in the United States until 1954, when the Public Health Service published a bibliography of American and British reports on respiratory disease among coal miners. Following this, various clinical and epidemiologic studies further documented the importance of CWP. At the direction of Congress, the Public Health Service began a comprehensive survey of the Appalachian coal fields in 1963. Of 2549 working miners and 1191 nonworking miners, 9% of the working and 18% of the nonworking miners were found to have radiographic evidence of pneumoconiosis. This study, published in 1968, together with the disastrous November 20, 1968, Farmington, West Virginia, mine explosion that killed 78 miners, triggered increased pressure from miners, their union (the United Mine Workers of America), and public health advocates, and led to passage of the Federal Coal Mine Health and Safety Act of 1969 (Public Law 1973). This was the first American mining law to recognize the importance of both health and safety hazards and provide a mandate for strong preventive measures. Since that time, awareness has grown indicating that CWP is not the only occupational pulmonary disease affecting coal miners. The results of the study by Rogan and colleagues were the first to show a clear link between chronic airflow obstruction and dust exposure, independent of CWP status, while Rae et al. demonstrated that respiratory symptom prevalence was related to level of dust exposure. Emphysema is increased in coal miners, and is related to both retained dust in the lung, and to cumulative dust exposure.
National Institute for Occupational Safety and Health, Division of Respiratory Disease Studies, 1095 Williowdale Road, Morgantown, WV 26505