Congrats, millions of cars will inevitably spring leaks in their fuel system because Corn Lobbyists are the loudest. I have no problem with ethanol as a whole being a viable vehicle fuel, just that corn is a ridiculous way of getting it. Why aren't we researching switchgrasses? waste bio-mass (food scraps, lawn clippings, sawdust, etc etc) derived ethanol? On that note, why is the diesel-cycle engine so repulsive to the EPA? Growing a crop intended as food (yes intended, it never existed in nature) but instead using it as a forced-on-the-consumer fuel yields literally no benefit other than higher corn prices. AH!
Here's the best part, not only will it damage your car if its not ready for it (2007 and later) but it will also void the warranty which (normally) states "only fuel with gasoline containing 10% or less Ethanol". What happens if the majority of stations start carrying E15 (labeled as gasoline mind you)? Is the Federal gov't going to make Ford fit a new fuel injection system on your '05 Mustang? Lastly, Ethanol also has less energy/volume yielding worse fuel economy than gasoline.
Source -> http://green.autoblog.com/2011/01/26/whos-unhappy-with-epas-e15-decision-lots-of-people/