Friday, August 14, 2009

Hazards of Silica and Health Effects of Silicosis

Occupational exposures to respirable crystalline silica occur in a variety of industries and occupations because of its extremely common natural occurrence and the wide uses of materials and products that contain it. At least 1.7 million U.S. workers are potentially exposed to respirable crystalline silica [NIOSH 1991], and many are exposed to concentrations that exceed limits defined by current regulations and standards.

Silicosis, usually a nodular pulmonary fibrosis, is the disease most associated with exposure to respirable crystalline silica. Although the reported mortality associated with silicosis has declined over the past several decades, many silicosis associated deaths still occur (nearly 300 deaths were reported each year during the period 1992-1995) [NIOSH 1996a; Althouse 1998]. In addition, the number of silicosis associated deaths among persons aged 15 to 44 has not declined substantially [CDC 1998a,b]. An unknown number of workers also continue to die from silica-related diseases such as pulmonary tuberculosis (TB), lung cancer, and scleroderma. The number of cases of silicosis and silica-related diseases in the United States today is unknown.


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