FAA Chimes In On Ethanol In Fuel

From the permalink-less AvWeb:

...while ethanol may be safer for the environment, it's toxic to airplane engines and the FAA says that if you can't find alcohol-free mogas for your STC'd aircraft engine, you'll have to switch back to 100LL. Alcohol increases the risk of vapor lock and can also introduce water into the fuel system as it cools at higher altitudes. It's also corrosive to rubber seals used in aircraft fuel systems and reduces the amount of power available from the fuel.