In a statement, the EPA said that "this decision and EPA's previous actions do not require the use or sale of E15. EPA will continue to work with stakeholders to ensure a smooth transition as businesses decide whether to introduce E15 into the market."
Despite the ruling, it's not clear how widely E15 will be adopted. On Friday, Mr. Dineen's group cited only one gas station, in Lawrence, Kan., that sells E15.
Major auto makers have said their warranties won't cover damage associated with E15 fuel, even though the EPA has said E15 is safe in newer vehicles.
And the National Association of Convenience Stores, a trade group representing gasoline stations, has raised concerns about whether the fuel can be safely stored in underground tanks and about liability for customers who use the fuel in the wrong engine.