The AAA says the Environmental Protection Agency and gasoline retailers should halt the sale of E15, a new ethanol blend that could damage millions of vehicles and void car warranties.

AAA, which issued its warning , says just 12 million of more than 240 million cars, trucks and SUVs now in use have manufacturers' approval for E15. Flex-fuel vehicles, 2012 and newer General Motors vehicles, 2013 Fords and 2001 and later model Porsches are the exceptions, according to AAA, the nation's largest motorist group, with 53.5 million members.

"It is clear that millions of Americans are unfamiliar with E15, which means there is a strong possibility that many may improperly fill up using this gasoline and damage their vehicle," AAA President and CEO Robert Darbelnet states  "Bringing E15 to the market without adequate safeguards does not responsibly meet the needs of consumers."

BMW, Chrysler, Nissan, Toyota and VW have said their warranties will not cover fuel-related claims caused by E15. Ford, Honda, Kia, Mercedes-Benz and Volvo have said E15 use will void warranties, citing  potential corrosive damage to fuel lines, gaskets and other engine components.

Gasoline blended with 10% ethanol has become standard at most of the nation's 160,000 gas stations, spurred by federal laws and standards designed to use more renewable energy sources and lessen the nation's dependence on foreign oil. Pushed by ethanol producers, the EPA approved the use of E15 -- a 15% ethanol-gasoline blend over objections from automakers and the oil industry.

EPA stickers affixed to gas station pumps say E15 is safe for use in virtually all vehicles 2001 and newer. But AAA -- in an unusual warning for a travel organization -- says the sale and use of E15 should be stopped until there is more-extensive testing, better pump labels to safeguard consumers and more consumer education about potential hazards.