Environmental impact of methyl tert-butyl ether (MTBE)

The primary function of MTBE as an additive in gasoline is to enhance the octane level of unleaded gasoline. By virtue of the oxygen atom it contains, it increases the oxygen-to-fuel ratio in gasoline. It has also been shown that addition of MTBE results in lower carbon monoxide and hydrocarbon emissions, and polycyclic aromatic hydrocarbons. MTBE oxidation, initiated by hydroxyl radicals, can yield a number of products such as tert-butyl formate, formaldehyde, methyl acetate, and acetone depending on the pathway. The environmental and health risks associated with MTBE are not clear. There are several unknowns about the health effects of this chemical. To date, overall, toxicity data show that MTBE has low toxicity in animals even though it is an irritant to the skin, eye, lungs and mucous membranes. The long-term effects are not known since it has recently been introduced into commercial use. Some toxicologists have reported that short-term, high-level exposures that often occur during accidental spills can cause euphoria, headache, dizziness, drowsiness, blurred vision, tremors, respiratory arrest and death. In view of its high production level, widespread use and exposure, inadequate and conflicting data on toxic effects, more research is needed.