MTBE Being Replaced with Ethanol All Over U.S.

Methyl Tertiary Butyl Ether (MTBE) is a gasoline additive used to boost octane and clean the air. It was introduced in 1979 as a replacement for lead. It was adopted as an oxygenate after the passage of the 1990 Clean Air Act Amendments to reduce carbon monoxide emissions. Refiners were asked to come up with a gasoline additive that would help cut air pollution. While the use of MTBE has been very effective in reducing the emissions of carbon monoxide and toxics, the incidence of MTBE contamination of groundwater increased significantly.

Unfortunately, MTBE dissolves easily in water and it moves faster and farther in the ground than other gasoline components. Where tanks have leaked, it has contaminated the groundwater making the water undrinkable. MTBE is made by blending methanol and a byproduct of gasoline refining. It has contaminated groundwater and has led California, New York and 15 other states to ban MTBE EPA has taken preliminary steps to ban it nationally. Corn-based ethanol is replacing MTBE in gasoline in those states that have enacted bans.