Ethanol is the stuff that you drink in beer, wines and spirits. http://en.wikipedia.org/wiki/Ethanol
I can't find any factual reference to it being corrosive or it being a solvent to any of the plastics, or rubber that is used in automobile fuel systems.
Apparently plastic fuel tanks are made of polypropylene and this chart says that polypropylene is ethanol resistant:
http://www.vp-scientific.com/polypropylene%20properties.htm
There are references to it being a problem on the web though:
http://www.google.com.au/webhp?rls=ig#sclient=psy&hl=en&newwindow=1&safe=off&rls=ig&site=webhp&q=ethanol+and+plastic+gas+tanks&aq=1&aqi=g3&aql=&oq=&pbx=1&fp=9ee942b6aec5b84d
Maybe the problems occur when it is mixed with hydrocarbons?
There are problems with ethanol attracting and mixing easily with water, which is corrosive to metal engine parts and fuel tanks, lines, etc.
Over the years I have had water in my fuel tanks a few times, if there is not too much in there, I have added methylated spirits to the tank to mix the water with the fuel. These days methylated spirits is not methyl alcohol but ethyl alcohol, another name for ethanol
In the U.S. they have E85 which is 85% ethanol fuel.
W.