Environmental effects and exposures to manganese from use of methylcyclopentadienyl manganese tricarbonyl (MMT) in gasoline
Lynam, D.R.; Roos, J.W.; Pfeifer, G.D.; Fort, B.F.; Pullin, T.G.
Neurotoxicology 20(2-3): 145-150
1999
ISSN/ISBN: 0161-813X PMID: 10385878 Document Number: 505666
Methylcyclopentadienyl Manganese Tricarbonyl (MMT) has been used since the 1970s in the U.S. as a gasoline octane enhancer. Extensive testing of the effects of MMT on regulated gaseous emissions carried out on a wide variety of automobiles showed that use of MMT resulted in significantly lower NOx emissions. Tests showed that less than 15% of the manganese from MMT combustion was emitted from the tailpipe, mostly in the PM2.5 fraction as manganese phosphate, with some manganese sulfate and a very small amount of manganese oxide. MMT has been used in Canada in virtually all unleaded gasoline for about 20 years. A probability-based study involving over 900 personal exposure samples in Toronto confirmed exposures to airborne PM2.5 Mn in the general population are quite low (.008 mug/m3 - median). Ambient levels of airborne manganese in Toronto are about the same as those in areas where MMT is not used. Exposures to manganese among the general population in Toronto are well within safe limits determined by the U.S. EPA and other standard setting bodies around the world.