Black lung
Black lung, also known as coal workers' pneumoconiosis, is a chronic respiratory disease caused by prolonged inhalation of coal and mineral dust in underground mining environments. It primarily affects those working in the coal mining industry, where exposure to high concentrations of dust can lead to serious health complications such as shortness of breath, weakness, heart disease, and lung cancer. Despite improvements in safety regulations and working conditions initiated by legislation like the Federal Coal Mine Health and Safety Act of 1969, the disease remains a significant health issue; approximately 16% of American coal workers were affected as of 2024.
Preventive measures have been implemented in mines, including enhanced ventilation systems, dust suppression techniques, and personal protective equipment that provides filtered air. Regulatory agencies monitor air quality and require regular medical screenings for workers to detect early signs of the disease. The ongoing challenge of black lung underscores the historical significance and industrial impact of coal mining, especially in regions heavily reliant on this energy source. Awareness and education about black lung are crucial for safeguarding the health of miners and addressing the ongoing risks associated with coal dust exposure.
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Black lung
DEFINITION: Chronic respiratory disease caused by long-term inhalation of coal and mineral dusts in closed coal-mining environments
Improvements of conditions for workers in coal mines have helped to reduce the incidence of coal workers’ pneumoconiosis, commonly known as black lung, but the disease has not been eradicated.
Since the Industrial Revolution, has provided energy for industrialized societies. With escalating demand, coal mining developed into a prevalent industry in many regions, such as Wales in Great Britain and the Appalachian Mountains of the United States. By the nineteenth century, the economies of such regions were dependent on coal.
The burning of coal produces gaseous and particulate (soot) pollution, and cities in the nineteenth century were characterized by black, soot-coated buildings and coal on other surfaces. Explosions caused by coal dust became common in coal mines and storage facilities. Slower to appear from the use of coal for energy were the greenhouse effect; coal workers’ pneumoconiosis, also called black lung, caused by chronic inhalation of coal dust; and acid rain. This particle-induced fibrosis-emphysema produces lesions in respiratory bronchioles that interfere with the and transport of oxygen in the lungs. Its symptoms are consistent with similar lung diseases: weakness and poor health, shortness of breath and oxygen starvation, heart disease, immune system irregularities, and lung cancers. It resembles diseases caused by fine airborne, respirable particles of (asbestosis); cotton, wood, and other plant-based dusts (farmers’ lung); and silicas such as quartz, glass, and sand (silicosis).
The greatest incidence of black lung occurs in underground mining. Drilling, pulverizing, loading, and transporting coal generate large dust concentrations, which are breathed into the workers’ lungs. Numerous safeguards have been instituted in coal mining to minimize the risks of workers developing black lung. Mine passages are ventilated by fans and baffles, and sophisticated routing produces multiregion flows that keep the air at face level fresh. Mines also utilize wetting and systems to keep coal wet and water mists to remove dust from the air.
Other developments have included ventilation and filtering systems worn on the body—for example, helmets that provide continuous streams of filtered air across workers’ faces. Research has been conducted into the development of drill bits and other components that can minimize the dust produced. This has included the replacement of steel bits with bits coated with tungsten carbide, polycrystalline diamond, or other hard ceramic or metallic films as well as optimization of thread geometry and bit speed.
Since the Federal Coal Mine Health and Safety Act of 1969 and the Mine Act amendments of 1977 in the United States, federal and state agencies (for example, the Mine Safety and Health Administration, or MSHA) have mandated that mine operators undertake efforts aimed at preventing black lung. Operators are required to sample mine air for deviations from permissible limits (PELs) of coal and silica dusts, methane, carbon monoxide, hydrogen sulfide, and sulfur dioxide; to report these deviations; and to take appropriate measures to correct them.
Operators are also required to provide medical screenings for employees over time. Periodic chest X-rays, measurements of lung capacity, cardiovascular checkups, and general blood, urine, and endocrine analyses warn of early signs of black lung. Worker health data are gathered through periodic questionnaires, providing insight into the overall risks in a given operation. Emphasis has been placed on education regarding black lung and the regulatory infrastructure that addresses it. Numerous government agencies offer information and services related to the disease, its prevention, its control, and compensation or support for those affected.
The MSHA’s PEL for coal dust is 2 milligrams per cubic meter (mg/m3) for unaffected workers and 1 mg/m3 for workers with any signs of black lung. The National Institute for Occupational Safety and Health (NIOSH) recommends an exposure level no greater than 1 mg/m3 for all workers. The Occupational Safety and Health Administration (OSHA) has set a slightly different PEL of 2.4 mg/m3 for coal dust with less than 5 percent silica. In 1968–69 the average dust in underground coal mines was 6 mg/m3, but since the Coal Act and the Mine Act, these averages have dropped to below 2 mg/m3.
The silica content of coal dust affects the epidemiology of black lung as well as permissible exposure limits. Less than 1 mg/m3 of silica can cause silicosis, and the current PEL for silicon is 0.1 mg/m3, with reduction to 0.05 mg/m3 being considered. Silica and dusts are generated during initial drilling through rock to reach the coal in coal deposits that are interspersed with bedrock.
Significant progress was made in the final decades of the twentieth century in fighting black lung and associated problems in coal mines. However, according to the American Lung Association, about 16 percent of American coal workers were affected by black lung in 2024.
Bibliography
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"Learn about Coal Worker’s Pneumoconiosis." American Lung Association, 7 June 2024, www.lung.org/lung-health-diseases/lung-disease-lookup/black-lung/learn-about-black-lung. Accessed 15 July 2024.
Levine, Linda. Coal Mine Safety and Health. Congressional Research Service, 2008.
Meyers, Robert A., ed. Coal Handbook. Marcel Dekker, 1981.
Ripley, Earle, Robert Redmann, and Adele Crowder. Environmental Effects of Mining. CRC Press, 1996.
Witschi, Hanspeter, and Paul Nettesheim, eds. Mechanisms in Respiratory Toxicology. Chapman & Hall, 1982.