In case anyone is interested in how the crystalline silica causes silicosis it works like this. Crystaline silica (crystobilite/quartz, etc) is very friable. When impacted it fractures readily in to micron sized particles. No when you observe these minute particles at extreme magnification you'll see that these particle are very angular with razor sharp edges, and that's the problem.
When inhaled into the lungs these razor sharp particles are entraped by the cilia of the culumnar epithelial tissue of which the lungs are composed. Since the edges of the silica particles are razor sharp they slice through the cell membranes of the epithelial tissue and kill that cell and they will continue to slice and kill the cells that the particles come into contact with.
When this happens the ruptured cells release antibodies that are detected by the immune system. The immune system responds by sending in a very specialized type of cell that deals with foreign objects. They are called polynuclear phagocytes or PMN's for short. The job of the PMN's is to envelop these particles with their cell membrane and then dissolve them with very strong enzymes, a process called lysing. Howver, they have the same problem that the epithelial cells have, the razor sharp silica particles again slice through the cell walls of the PMN's thus killing them. So if to use an analogy, if PMN's are the pick up trucks the body used to clean up debris than the Macrophages are the big assed dump trucks. When the PMN's fail to clean up the debris the immunse system signals in invastion into the affected area by macrphages. They, like the PMN's are phogcytic cells only much larger. Magrphages are what make the permenant staining of the skin by tatoo ink possible. They clean up bulk debris. Once agan though though the razor sharp edges on the silica particles comes into play as they also slice through the cell walls of the macrophages and kill them too.
So now it's a serious problem. Two major attempts to clean up the dangerous foreign debris have failed so now the immune systems sends in a speciliazed type of cell called fibroblast. The fibroblast secrete collogen fibers around the silica particles which fixes them in place so that they can no longer damage lung tissue.
However, that comes at the cost of the surrounding epithelial cells being able to peform their primary function, gaseous exchnage. If enough micron sized particles of silica are inhaled then to much of the surface area of the lungs will become covered in fibers that have immobalized the silica particles.
That creates two problems. The first, as mentioned is it intereferes with the lungs ability to exchange gasses. It also decreases the lungs elastic properties which reduces the lungs vital capacity, that is the lungs ability to expand so as to exhange more gases as demand increases. With the end result that the victim who has inhaled significant ammounts of crystaline silica will have trouble breathing. If a large enough area of the lungs are affected, than silicosis becomes life threatening.
