Silicosis is a lung disease caused by inhaling crystalline silica dust. Exposure to silica dust—and thus the risk of contracting silicosis—is especially high among iron and steel foundry workers, sandblasters, rock drillers, miners, and workers who produce pottery, glass, and abrasives.
There are three forms of silicosis: simple, complicated, and acute. After a particle of silica is inhaled, it eventually becomes surrounded by fibrous scar tissue. The scar tissue forms a small nodule (lump) in the lung. Simple silicosis is recognized by the presence of many small nodules on a chest X ray. It usually takes 10 to 20 years to develop. Simple silicosis generally does not affect the function of the lungs. It may, however, progress to complicated silicosis (also called progressive massive fibrosis), in which nodules cluster together to form masses of fibrous tissue. When more than a third of a lung becomes fibrous, the patient experiences shortness of breath and abnormal lung function. Complicated silicosis sometimes leads to death. Acute silicosis develops much more rapidly than complicated silicosis and is usually fatal in two or three years. It causes the air sacs of the lungs to fill with fluid. It occurs in workers exposed to extremely high concentrations of silica dust, such as sandblasters and rock drillers.
There is no effective treatment for silicosis. Prevention is best achieved by using ventilation systems and engineering techniques that limit silica dust exposure in the workplace.
