Is ethanol bad on your engine?

Ethanol is primarily used to oxygenate the gas and replace the chemical MBTE, which pollutes groundwater. HOWEVER, since most ethanol in the US comes from corn, it is important to note that using ethanol in gasoline causes GREATER pollution than just gasoline alone. This is because it actually takes more energy to produce corn based ethanol than is extracted from it. Until better technologies for ethanol production are available (e.g. algae), it is best for the environment to avoid gas containing ethanol if possible (some states mandate it).

The idea in more recent years was to reduce dependence on foreign oil (most of ours comes from Canada, a smaller proportion coming from the Middle East), but the end result has been an unfortunate upward swing in global corn prices which affects the people who actually use corn as food.