as fillers in the rubber industry, in tyre compounds, as free-flow and anti-caking agents in powder materials, and as liquid carriers, particularly in the manufacture of animal feed and agrochemicals other uses are found in toothpaste additives, paints, silicon rubber, insulation material, liquid systems in coatings, adhesives, printing inks, plastisol car undercoats, and cosmetics. According to the different physico-chemical properties, the major classes of synthetic amorphous silica are used in a variety of products, e.g. These synthetic forms may be classified as (1) wet process silica, (2) pyrogenic ('thermal' or 'fumed') silica, and (3) chemically or physically modified silica. Intentionally manufactured synthetic amorphous silicas are without contamination of crystalline silica. This applies particularly to well-documented pneumoconiosis among diatomaceous earth workers. The major problem in the assessment of health effects of amorphous silica is its contamination with crystalline silica. This review summarizes the current knowledge about the health effects of amorphous (non-crystalline) forms of silica. Occupational exposure to crystalline silica dust is associated with an increased risk for pulmonary diseases such as silicosis, tuberculosis, chronic bronchitis, chronic obstructive pulmonary disease (COPD) and lung cancer.

Amorphous silica