Many Zinc Plant employees asked me about exposure to manganese dioxide. To assist workers understand the health effects of exposure to manganese I have reviewed world literature on the subject of manganese and its health effects.

Recently, the Ministry of Labour have adopted a new manganese exposure level.  These new exposure levels were recently cut from 5.00 mg/m3 to 0.2 mg/m3. This is over major          decrease in 8-hour exposure to Ontario workers.

Manganese (Mn) is a natural occurring element that is found in rock, soil,    water and food.  All humans are exposed to manganese on a daily  basis and is a normal component of the human body.  Research on the   subject estimate the level of 1-5 mg/m3 is a safe intake for  human adults.

However, exposure to high levels of Mn via inhalation or ingestion can cause   major adverse health effects. Manganese exposure can have long-term adverse health effects on the lungs, central    nervous system and reproductive systems. Effect to the nervous system can include neurological and neyrophysiatric symptoms that can culminate a Parkinson's like disease known as magnesium. Lung inflammations have been in reported in workers following a single      exposure to manganese dioxide of levels of 2.8 - 43 mg/m3.

From the current research, it is very difficult to determine when manganese dioxide affects the human central nervous system. In chronic expose cases, workers were noticed to have   decreased   libido, impotence, reduced concentration, loss of coordination, muscle cramps, nervousness and