Manganese produce a parkinsonism-like illness characterized by movement abnormalities. This condition is not responsive to typical therapies used in the treatment of PD, suggesting an alternative pathway than the typical dopaminergic loss within the substantia nigra. Manganese may accumulate in the basal ganglia, leading to the abnormal movements. A mutation of the SLC30A10 gene, a manganese efflux transporter necessary for decreasing intracellular Mn, has been linked with the development of this Parkinsonism-like disease. The Lewy bodies typical to PD are not seen in Mn-induced parkinsonism. Animal experiments have given the opportunity to examine the consequences of manganese overexposure under controlled conditions.
Methylcyclopentadienyl manganese tricarbonyl as well as its rapid photo-degradation properties, it has been concluded in multiple technical and global regulatory assessments that significant impacts to human health or the environment from MMT use are not anticipated. NICNAS concluded that there is "low occupational risk associated with MMT" both "for workers involved in formulating and distributing LRP or aftermarket fuel additives and those involved in automotive maintenance". Further, they also concluded that there is a "low risk" to the public from the use of MMT. Significant human or environmental exposures associated with manganese compounds (manganese phosphate, manganese sulphate and manganese tetraoxide) from the combustion