The Supreme Court Monday ruled it would not address a challenge of a lower court's ruling regarding E15.
A coalition of groups earlier this year appealed a D.C. Circuit Court decision rejecting a challenge to EPA's grant of partial waivers for use of the ethanol-gasoline blend E15.
The groups behind the petition said the D.C. Circuit incorrectly concluded that none of the 17 petitioners had standing to challenge the E15 partial waivers.
Further, the American Petroleum Institute, one of the groups in the coalition, said EPA's testing of engines and fuel systems was incomplete before allowing the use of E15. Had it waited, API said, "Then it would have discovered that E15 is not safe for millions of vehicles now on the road."
Other manufacturing groups against E15 also say it hasn't been through proper testing to ensure safety in some engines.
"Renewable fuels are an important part of our energy security, but it is not in the long term interest of the government, automakers, fuel providers or the ethanol industry itself to find out down the road that vehicle problems are occurring from rushing E15 into the national marketplace," an Auto Alliance statement noted.
"EPA approved E15 for cars retroactively, even though those vehicles were never designed to run on this more corrosive fuel. Automakers continue to urge consumers to check their owner's manuals for the recommended fuel to use safely in their vehicles."
Ethanol supporters maintain the safety of E15 and hailed the Supreme Court's decision to not hear the appeal. Tom Buis, CEO of Growth Energy, said now that the decision of the court has been announced, the group will work to bring more blends into the marketplace.
"This was not just a victory for consumers, but also for America's energy security, economy and environment," Buis said.
National Farmers Union also applauded the decision.
"America's farmers strongly support the growth of the biofuels industry, and stand ready to contribute in a meaningful way to the economic and environmental well-being of the United States."
Lawmakers have previously sparred over the issue, with Sens. Wicker and Vitter late last winter calling for an overturn of E15 approval and others defending the Environmental Protection Agency's decision to allow the blend.
Universities and private companies have taken on studies to determine the effects of E15 on engines, though they have produced differing conclusions.