Manganese is an essential trace element in the metabolism of all living
organisms. Nevertheless, excessive doses are toxic, and the resultant disease
may arise in the pulmonary system or the central nervous system (CNS).
Manganese exposure is usually via inhalation (the risk varying with the
manganese species involved and with particle size).
There is extensive literature concerning manganese toxicity and acute or
chronic manganese poisoning as a result of industrial exposure to manganese
oxide dust and fume.
Advanced manganese poisoning, referred to as manganism, can
lead to extensive disablement (fortunately, such cases are rare today).
Specific measures relate particularly to: reducing exposure levels and time of
exposure, the use of exhaust ventilation, having workers in isolated control
rooms or in air-conditioned or filtered air cabins, making available better
protective equipment. Management of these various measures is clearly of great
Many countries have issued restrictions concerning the permissible
amount of airborne manganese in dust and fumes (threshold limit value) and
these seem likely to become tighter in the future.
Medical studies into the effects of exposure to manganese are underway
in various countries as well as research into mechanisms of possible toxic
action within the body.