When workers inhale crystalline silica, the lung tissue reacts by developing fibrotic nodules and scarring around the trapped silica particles. This fibrotic condition of the lung is called silicosis. If the nodules become extensive or grow too large, breathing can become difficult and disability and/or death may result. Silicosis is an incurable disease. Silicosis victims are also at a higher than normal risk of developing active tuberculosis. There is also increasing medical evidence that crystalline silica exposure causes lung cancer. Medical evaluations of silicosis victims usually show the lungs to be filled with silica crystals. A worker's lungs may react more severely to silica sand that has been freshly produced (sawed, hammered, or treated in a way that produces airborne dust). This factor may contribute to the development of acute and accelerated forms of silicosis.
The chance of developing silicosis, a virulent form of black lung, after 20 years of working at a strip mine is 61 percent.