Ethanol Replaces MTBE as Oxygenate...........But

The 1990 Clean Air Act amendments required the use of reformulated gasoline (RFG) in metropolitan areas in noncompliance of the law. One requirement for RFG was that it contain 2 percent oxygen content by weight - - oxygenates. The two most economical oxygenates are Methyl Tertiary Butyl Ether (MTBE) and ethanol. MTBE, which comes from the oil companies, quickly became the most widely used oxygenate, while ethanol, whicih comes from farmers, became a distant second.

By the mid-1990s, traces of MTBE began showing up in groundwater supplies. Oil companies became the targets of lawsuits from property owners and municipalities whose water had been affected. The fuel industry's best defense was that it was using MTBE to comply with the 2 percent oxygen content requirement and thus merely following the law. Of course, critics point out that the law did not specify the use of MTBE. The Energy Policy Act of 2005 repealed the 2 percent oxygen content requirement. The act also bans the use of MTBE beginning on May 6, 2006.

EPA already used its Energy Policy Act of 2005 authority to revoke the two percent oxygen content requirement for reformulated gasoline (RFG) nationwide in order to reduce production burdens. Currently, about 30 percent of gasoline is RFG. The revocation takes effect nationwide on May 6 and in California 60 days after the regulation's publication in the Federal Register.