The U.S. Environmental Protection Agency (EPA) has waived
a limitation on fuel sales to allow the sale of fuel containing
up to 15% ethanol, known as E15, for model year 2007 and
newer cars. EPA is proposing a new pump label for E15 to
help ensure consumers use the correct fuel.

Source: http://www.eere.energy.gov/news/news_detail.cfm/news_id=16423