Review of Particles Inhaled in the Workplace

Exposure to silicaceous dusts is a major occupational health concern in numerons industries. Much of the silicon in the earth is combined with other elements to form silicates. Various anions and cations are substitnted into the crystalline silica matrix. Minerals such as kaolin, an aluminum silicate, and talc, a magnesium silicate, are silicate minerals that are used in their pnre form. Many minerals of commercial importance are composed of mixtures of silica and silicates, such as feldspar and muscovite, in an infinite range of combinations. The pulmonary disease associated with silica exposure is greatly influenced by the silicate content of the material. It has been estimated that approximately 8.2 million workers in the United States are potentially exposed to crystalline silica dust each year. 

Silicosis is the major disease of concern following exposure to free crystalline silica. Nnmerous industries have the potential for exposing workers to free silica (Table 2). There are three forms of silicosis that are dependent on the natnre of the silica exposure these forms are silicotic alveolar proteinosis, accelerated silicosis, and chronic silicosis. 

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Quarrying, mining, and dressing of sandstone, granite, and slate Mining of tin, hematite, graphite, copper, gold, and other minerals The pottery industry 

Manufaeture of refractory products, such as silica bricks 

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