Actually MTBE was originally viewed as a top octane enhancer to replace lead. Its oxygenate property added to its "lustre" as a saviour. It turned out to be not only corrosive but when leaked out of storage tanks a major ground water problem. Its made from Methanol(basically wood alcohol) not Ethanol(grain alcohol). I was working for Airtex (biggest fuel and water pump maker) back then and the problems especially for fully submerged electric fuel pumps was major.

Spaw