Explanation:

A chronic occupational lung disease contracted by the prolonged breathing of coal mine dust. The silica and carbon in the coal dust cause black lung disease. About one of every 20 miners studied in the US has X-ray evidence of black lung disease, a form of pneumoconiosis. In its early stages, called simple pneumoconiosis, the disease does not prevent the miner from working or carrying on most normal activities. In some miners, the disease never becomes more severe. Pneumoconiosis is not reversible. There is no specific treatment. Black lung disease has gone by many names, including anthracosis, black lung, black spittle, coal worker’s pneumoconiosis, miner’s asthma, and silicosis.