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

AAA, whichissued its warning Friday, says just 12 million of more than 240 millioncars, trucks and SUVs now in use have manufacturers' approval for E15.Flex-fuel vehicles, 2012 and newer General Motors vehicles, 2013 Fordsand 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 withE15, which means there is a strong possibility that many may improperlyfill up using this gasoline and damage their vehicle," AAA President andCEO Robert Darbelnet tells USA TODAY. "Bringing E15 to the marketwithout adequate safeguards does not responsibly meet the needs ofconsumers."

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

Gasoline blended with10% ethanol has become standard at most of the nation's 160,000 gasstations, spurred by federal laws and standards designed to use morerenewable energy sources and lessen the nation's dependence on foreignoil. Pushed by ethanol producers, the EPA approved the use of E15 -- a15% ethanol-gasoline blend -- in June over objections from automakersand the oil industry. It's been available at a handful of outlets inKansas, Iowa and Nebraska since July.

EPA stickers affixed to gasstation pumps say E15 is safe for use in virtually all vehicles 2001 andnewer. (USA TODAY made repeated requests for EPA comment.)

ButAAA -- in an unusual warning for a travel organization -- says the saleand use of E15 should be stopped until there is more-extensive testing,better pump labels to safeguard consumers and more consumer educationabout potential hazards.

Bob Dinneen, CEO of the RenewableFuels Association, says E15 is safe for virtually all post-2001vehicles, based on extensive government-sponsored testing. "We thinkthe (EPA) warning label should be sufficient to notify consumers,''Dinneen says. "There are no corrosive issues with E15. If there's anissue with E15 (damaging vehicles) we're going to know about it, and theEPA is going to know about it."

But the American PetroleumInstitute says a three-year study conducted by automakers and the oilindustry found that E15 is a consumer safety issue for a majority ofdrivers with pre-2012 vehicles. "Our testing of a range of ethanollevels at 15% to 20% has identified issues about engine durability,''API group director and engineer Bob Greco says.

The National Association of Convenience Stores says it's also worriedabout the effect of E15 on station pumps and fuel lines. "The EPA saysits OK to sell it, but for most retailers, there is too muchuncertainty related to consumer demand and liability protection,especially if it's later determined E15 is a defective product or thereare problems,'' spokesman Jeff Lenard says.

Scott Zaremba, whohas been selling E15 blends at several of his eight Zarco 66 stations inKansas since July, says no customers have complained. He's alsofueling his 2001 Chevy pickup with E15 blend.

"The same complaintscame when 10% blend came in -- the world was coming to an end,'' saysZaremba, 47. "E15 burns well and has great performance, and four peopletell me it gives them better gas mileage. I don't see any major issueswith it -- yet."