It seems like a great idea: Increase the amount of renewable ethanol from grain at the gas station and decrease America's reliance on foreign oil.

But a push to add another 50 percent to the ethanol content of some automobile fuel has opened a barrel of worms. Automakers say they don't know how it will affect their cars; power-equipment and boat manufacturers are predicting calamitous mis-fueling; and gas station owners are looking at a slew of legal and logistical impediments.

The Environmental Protection Agency has approved a request from the ethanol industry to allow ethanol content in a gallon of gas to climb from 10 to 15 percent. The waiver to the Clean Air Act to permit so-called E15 fuel applies only to cars and light trucks made since model year 2007, but the Outdoor Power Equipment Institute and manufacturers argue that once gas stations sell it, consumers will mis-fuel their power equipment, with terrible results.

The availability of E15 could produce "a train wreck in the marketplace," said the institute's attorney, Bill Guerry.

Opponents of E15 are considering a concerted legal action to try to reverse the waiver. "We don't know the long-term effects of E15 on automobiles," said Gloria Bergquist of the Alliance of Automobile Manufacturers. "There's a sweep of studies underway now, and we had urged EPA to wait until next year when more of these studies would be concluded."

In approving the waiver Oct. 13, EPA Administrator Lisa P. Jackson said "thorough testing has shown that E15 does not harm emissions control equipment in newer cars and light trucks."

For veteran power-equipment guys such as Mick Matuskey, the prospect of E15 entering the fuel stream is vexing. Matuskey, co-owner of Power and Lawn Equipment in Gaithersburg, has been in the business for 44 years and remembers when snowblowers, chain saws and mowers lasted much longer.

"You're getting half of the life out of the product today compared to 30, 40 years ago," he said.

Cheaper components and higher running temperatures are taking their toll. But critics say a 15 percent ethanol blend would shorten engine life more and make equipment prone to fuel leaks and fire hazards. Apart from causing engines to run hotter, ethanol fuel eats away at rubber components.

"E15 is going to make fuel lines on older equipment turn to mush a lot faster," Matuskey said. "You've got spillage and environmental issues as well as fire and safety issues."

Prentiss Searles of the American Petroleum Institute said, "Having seals fail on your backpack blower isn't a good thing, because you've got a gas tank sitting on your back."

Old technologies



Tools such as trimmers, mowers and blowers generally use engine technologies long abandoned by carmakers: air cooling, carburetion and, often, two-cycle engines fueled by an oil-gas mix . Ethanol blends cause engines to run leaner and hotter - modern auto engines can adjust for that; lawn mowers and chain saws cannot.