Pneumoconiosis, also known as “coal workers’ pneumoconiosis”, miner’s asthma, or black lung disease, is a lung condition caused by the inhalation of dust, characterized by formation of nodular fibrotic changes in lungs. These changes may be in the form of industrial bronchitis, a condition which abates 3 to 6 months following the cessation of exposure, or permanent changes in the lung parenchyma, taking the form of macules, micronodules, macronodules, or progressive massive fibrosis. The changes may be exhibited on chest x-rays or CT scans of the chest.
Rarely does simple pneumoconiosis cause significant pulmonary problems. Coal miners with simple coal workers’ pneumoconiosis with obstructive airways dysfunction usually have been or are tobacco smokers. Many substances can cause pneumoconiosis including asbestos, talc, coal mine dust, kaolinite, and other metal compounds.
Depending on the type of dust, variants of the disease are considered. For example there are silicosis, also known as grinders’ disease; and pneumosilicosis, which is caused by the inhalation of the dust of stone, sand, or flint containing silica. Because many common minerals contain silica, there are different types of silicosis.
What Is It?
Pneumoconiosis is a lung condition that is caused by inhaling particles of mineral dust, usually while working in a high-risk, mineral-related industry. At first, irritating mineral dust can trigger lung inflammation, which causes areas of the lung to be temporarily damaged. Over time, these areas can progress to form tough, fibrous tissue deposits. This stage of pneumoconiosis is called fibrosis. Fibrosis stiffens the lungs and interferes with the lung’s normal exchange of oxygen and carbon dioxide.
There are several different types of pneumoconiosis. The most common types include:
- Asbestosis — Asbestos is the general name for a family of irritating fibrous minerals that are mined from underground deposits and used in the manufacture of home insulation, fireproof materials, tiles for floors and ceilings, automobile brake linings, and other products. Workers with the highest asbestos exposure include miners, construction workers, demolition workers, shipbuilders and auto mechanics who work with brakes. Asbestos exposure also can affect people who live or work in buildings where asbestos-containing building products are deteriorating. In most cases, signs of asbestosis do not develop for 20 or more years after a person is first exposed to asbestos dust.
- Silicosis — This form of pneumoconiosis affects people who work with silica, usually in the form of quartz that is found in sand, sandstone, slate, some clays, granite and other ores. Workers with the highest exposure to silica include sandblasters, miners, tunnel builders, silica millers, quarry workers, foundry workers, and those who make ceramics or glass. Silicosis can cause progressive fibrosis in the lung with a significant decrease in lung function, especially in cigarette smokers.
- Coal worker’s pneumoconiosis —This form of pneumoconiosis is caused by inhaling carbon particles from coal, graphite, lamp black or carbon black. It most often affects people who mine, process or ship coal; graphite miners; and workers who manufacture synthetic graphite, lamp black or carbon black. Like silicosis, coal worker’s pneumoconiosis can cause significant fibrosis, primarily in miners who have worked for decades without protective equipment.
Pneumoconiosis sometimes does not cause any symptoms. When symptoms develop, they can include:
- Cough (with or without mucus)
- Shortness of breath, especially during exercise
If pneumoconiosis causes severe lung fibrosis, breathing can become extremely difficult. When this happens, the patient’s lips and fingernails may have a bluish tinge. In very advanced disease, there also may be signs of leg swelling caused by too much strain on the heart.
Your doctor will ask about your exposure to mineral dusts, the number of years you were exposed, and whether you used protective clothing and equipment. Your doctor will examine you, paying special attention to your chest. This will be followed by a chest X-ray, which will be compared to a set of standard X-rays published by the International Labor Office for the evaluation of pneumoconiosis. Your doctor may order breathing tests, called pulmonary function tests. In some patients, a more detailed computed tomography (CT) scan of the chest is necessary. Less often, a doctor will order a test called a bronchoscopy with a lung biopsy. In this test, a flexible tube is inserted into a lung and a small piece of lung tissue is removed to be examined in a laboratory.
Pneumoconiosis almost always can be prevented. To reduce your risk, you can:
- Limit work-related exposure to mineral dusts
Workers who routinely deal with mineral dusts always should use approved measures (protective equipment and clothing) to limit their exposure and keep from bringing mineral dust home on their clothing. If a mask or respirator is worn as a protection against dust, it must fit properly and be used according to the manufacturer’s directions.
- Prevent exposure to asbestos at home
Check your house, especially if you own an older house, for areas of exposed asbestos-containing insulation or deteriorating asbestos. The asbestos in these areas must be removed or safely sealed away (encapsulated) professionally.
- Avoid cigarette smoking
Smoking worsens the harmful effects of pneumoconiosis. If you smoke, ask your doctor about proven ways to quit.