Health risks with exposure to silica fume?

Answer 1

Silica fume, also known as microsilica, is a byproduct of the combustion of quartz, coal and wood chips during the production of silicon metals. silica improves compressive strength, bond strength, and the abrasion resistance of concrete. Prior to the 1970s, its release into the atmosphere was permitted, but environmental concerns eventually forced its collection and deposition into landfills. It then became economical for silica fume to be used in various applications, chiefly in high-performance concrete. Consisting of fine silicon dioxide particles that are approximately one-hundredth the size of the average cement particle, silica fume is the cement substitute of choice where high strength is critical, such as in high-rise buildings. Cement that contains silica fume looks darker than ordinary cement. Although a respirator should be worn while handling pure silica fume, a cement-silica fume mix is not considered dangerous to humans.