Back in February 2011, the US House overwhelmingly voted to block the sale of E15 fuel in America. For the uninitiated, E15 is a version of petrol that is blended with ethanol - in this case 15% ethanol. The argument for E15 fuel is that it will help reduce the US's dependence on foreign oil. However it comes with a downside - it's corrosive and will only work in some vehicles sold after 2007 - earlier models will have problems with the seals and fuel lines. (The EPA claim the restriction is for vehicles sold after 2001). In addition, it reduces the overall efficiency of internal combustion engines. Because E15 has less energy per volume than E10 (what we're forced to use right now) and just plain old petrol, that translates to lower gas mileage. Lower gas mileage results in more fill-ups which means more money for the big oil companies. Many car manufacturers have gone so far as to say that if you do use E15, you'll void your factory warranty on fuel-line components and the engine itself.
If you prefer not to use the current E10 blend (and who would blame you), you can find a list of gas stations near you (if you live in the US) that still sell unpolluted petrol. I know in my current VW, when I run it on unblended premium, I get an average 2.5mpg more than with E10 and the engine runs a lot smoother. Find the list here, but be warned it gets smaller by the day: Pure gas. You can read the EPA press release on E15 here: EPA approves E15 gasoline.