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.
This anti-caking agent is used in some dry powdery foods, personal powder products (bath, baby, face, etc), creams, and supplements. Prolonged inhalation of talc (magnesium silicate) can cause lung problems because it is similar in chemical composition to asbestos, a known lung irritant and cancer-causing agent.