Pneumoconiosis. Light micrograph of a section through lung tissue affected by pneumoconiosis, or coal workers' lung (CWL), a disease caused by the inhalation of pollutants such as coal and silica dust. Deposits of dust particles (black) can be seen in the tissue. The accumulation of these deposits leads to inflammation, fibrosis (scarring) and ultimately necrosis (death) of the lung tissue. Symptoms include breathlessness, a chronic cough and increased susceptibility to lung infections. There is no cure.