Two powerful farm-state senators introduced a bipartisan bill yesterday that would triple the use of ethanol over the coming decade and help replace the controversial gasoline additive MTBE. The bill, sponsored by Senate Minority Leader Tom Daschle (D-S.D.) and Sen. Richard Lugar (R-Ind.), would let states opt out of the federal requirement that gasoline in polluted urban areas be oxygenated to help reduce carbon-monoxide emissions. The problem is that the chemical most frequently used to meet the oxygen requirement is MTBE, which contaminates drinking water supplies and is a suspected carcinogen. In place of the oxygen requirements, the bill would require gradual increases in the use of biodiesel and ethanol, which is also used to oxygenate fuel. U.S. EPA Administrator Carol Browner called the bill “a major step in the right direction.”