It also is in the air and the soil. Because of the varying proportion of crystalline silica in rock and the dynamic exposure that workers have to the material in construction, hard data on exposure is hard to find or calculate. But health experts estimate that thousands of construction workers are exposed each year and that at least 250 workers in all industries die annually from silicosis. The disease is similar to asbestosis in that it sometimes takes years to manifest itself, is difficult to diagnose and can be prevented with the proper personal protective equipment or engineering controls. The more dust inhaled, the more scarring there is.
Heart disease is a companion problem.
In severe cases, victims end up with pulmonary impairment to the point that they have to go on oxygen. How much silicosis people will develop depends on genetics and degree of exposure to respirable quartz, which is silica dust ranging from .2 or .3 microns in diameter to 5 microns, says Levin. Nonetheless, Levin believes that even the smallest particles have a biologic impact. Levin says the genetics angle is not well understood. And there is a more ominous specter.