The average typing speed is 38-40 words per minute (wpm) for adults  in a professional working environment (despite many incorrect  reports on the web that it is 50-60 wpm).
Chronic Health Effects The following chronic (long-term) health effects can occur at some time after exposure to Mica and can last for months or years: Cancer Hazard * Some Silicas have been shown to cause cancer in animals. The risk of cancer in humans from Mica is unclear at this time.
Methylmercury and Dimethylmercury. The toxic effects of mercury depend on its chemical form and the route of exposure. Methylmercury is the most toxic form. It affects the immune system, alters genetic and enzyme systems, and damages the nervous system, including coordination and the senses of touch, taste, and sight.