Grease Guzzlers

"Some people laugh," said Tonken, 32, of Rockville, as he drove in Northwest Washington. "That's unfortunate. They're the nonbelievers."

Jim Hickey, 46, of New Market also gets his share of wisecracks as he drives his 1984 Volvo equipped with a VW diesel engine. He fuels his car with canola oil that has fried tempura shrimp, vegetables and chicken at The Orchard, his whole-foods restaurant in Frederick.

"It smells more like a chicken barbecue," Hickey said. "Everyone laughs about it." And some ask: "How's the tempura taxi running?"

Jokes aside, the idea is catching on, said Lee Briante, a spokesman for Greasecar in Amherst, Mass., one of the largest manufacturers of conversion kits.

The company has gone from selling about 20 kits a month in 2000 to as many as 100 a week this year, he said. In its six years of existence, the company has sold 3,000 kits nationwide, including 50 in Virginia, 30 in Maryland and 10 in the District.

"In general, we see a direct relationship with fuel prices to sales," Briante said. "Over the last two years, I'd say more folks just can't afford to run their vehicles."

There is no official count of the number of U.S. vehicles fueled by pure vegetable oil. Briante and Charles Anderson, owner of Golden Fuel Systems of Springfield, Mo. , another leading manufacturer of conversion kits, guess that there are 8,000 to 10,000.

Still, Jonathan Overly, executive director of the East Tennessee Clean Fuels Coalition, sees limited growth ahead. "It's really going to be your green community," he said. And people must be determined enough to collect used oil from restaurants.

"There's a whole lot of individuals who don't want to do that," Overly said.

Leahy, a lawyer for a wildlife conservation group, noted that the resources are finite. "I don't think there's enough used cooking oil to fuel the masses," he said.

A more practical option, Overly and others said, is biodiesel, a more sophisticated formulation that combines plant or animal fats and some form of alcohol, such as methanol. It burns cleaner than conventional diesel fuel and requires no conversion kit for the diesel engine.

Some municipalities, including Falls Church, use biodiesel to run fleets of trucks or buses. About 75 million gallons were produced in the United States last year.

Another popular alternative, ethanol fuel, is a mix of fermented corn sugar and gasoline that can be used in regular car engines. Last year, nearly 4 billion gallons were produced across the country.

Still, the "greasers" remain true to their low-tech fuel. And for now at least, getting grease is a cinch. Most restaurants have to pay to dispose of it, so they're happy to give it away.

One recent evening, Leahy pulled up to the Barking Dog in downtown Bethesda to pick up his fuel, which he would take home to filter.

As kickball players filed through the front door for a night of beer and frivolity, owner John McManus brought out a five-gallon pickle pail for Leahy. The pickles were long gone; soy oil sloshed to the brim.

"I wish everyone would do it," McManus said.

Staff researcher Karl Evanzz contributed to this report.