(See also Overview of Environmental Lung Diseases.)
Coal workers’ pneumoconiosis is an environmental lung disease that results from inhaling coal dust or graphite over a long time, usually 20 years or more. Although coal dust is relatively inert and does not provoke much reaction, it spreads throughout the lungs and shows up as tiny spots on an x-ray. Coal dust may block the airways.
In simple coal workers’ pneumoconiosis, coal dust collects around the small airways (bronchioles) of the lungs. Every year, 1 to 2% of people with simple coal workers’ pneumoconiosis develop a more serious form of the disease called progressive massive fibrosis, in which large scars (at least ½ inch [about 1.3 centimeters] in diameter) develop in the lungs as a reaction to the dust. Progressive massive fibrosis may worsen even after exposure to coal dust stops. Recently, rapid development of progressive massive fibrosis has been found among young coal miners, especially in the eastern United States. Lung tissue and the blood vessels in the lungs can be destroyed by the scarring.
In Caplan syndrome, a rare disorder that can affect coal miners who also have rheumatoid arthritis, large round nodules of scarring develop quickly in the lung. Such nodules may form in people who have had significant exposure to coal dust, even if they do not have coal workers’ pneumoconiosis.
Simple coal workers’ pneumoconiosis usually does not cause symptoms. However, many people with this disease cough and easily become short of breath because they also have an airway disease, such as chronic bronchitis or emphysema. These disorders are more likely to occur in smokers, so smokers with coal workers’ pneumoconiosis are more likely to have symptoms.
The severe stages of progressive massive fibrosis, on the other hand, cause coughing and often disabling shortness of breath.
Doctors make the diagnosis after noting characteristic spots on a chest x-ray or computed tomography (CT) scan of a person who has been exposed to coal dust for a long time—usually someone who has worked in a coal mine for at least 10 years.
Tests of lung function and measures of the amount of oxygen in the blood are done to monitor the disorder.
Prevention is crucial because there is no cure for coal workers’ pneumoconiosis. The disorder can be prevented by adequately suppressing coal dust at a work site. Ventilation systems may help. Face pieces (masks) that filter and purify the air may provide some additional benefit, but the protection is limited.
Doctors usually recommend that coal workers have chest x-rays every year, so that the disease can be detected at a relatively early stage. If the disease is detected, the worker should be transferred to an area where coal dust levels are low to help prevent progressive massive fibrosis. Coal workers who smoke are encouraged to stop (see Smoking Cessation). Workers may be given the pneumococcal vaccine and an annual influenza vaccination to help protect against infections to which workers may be more vulnerable.