But the oil change never came.

This week, the fast-food giant agreed in Marin County Superior Court to pay $7 million to the American Heart Association for a super-sized public education campaign about trans fats, or partially hydrogenated vegetable oil, the substance that makes crackers crisp and is found in the fryers of most fast-food chains.

In addition, McDonald's agreed to spend $1.5 million to publish notices of its progress in finding an oil substitute.

Researchers say trans fats, a byproduct of hydrogenating vegetable oils, are worse for the heart than saturated fats. And even though food manufacturers don't have to disclose trans fat amounts on food labels until 2006, when a new federal law takes effect, trans fat-free products are filling supermarket shelves.

But restaurants won't be required to disclose their trans fat loads, which explains why McDonald's scored glowing press in September 2002 by announcing that it would voluntarily cut the trans fat levels in its fryers by the following February.

When the company didn't hit its deadline -- the chain said it had issued a news release in February 2003 saying its plans had been delayed -- San Francisco public interest attorney Stephen Joseph, president of BanTransFats.com, sued. He contends that McDonald's did not take sufficient steps to inform the public that it had failed to change its oil.

Joseph asked the fast-food chain to use a new cooking oil as soon as possible and to tell consumers it hadn't yet dropped the old trans-fatty stuff. In a separate class-action suit, plaintiffs also represented by Joseph claimed that had they known that the oil hadn't been switched, they wouldn't have bought McDonald's sandwiches.

In the settlement reached this week, McDonald's agreed to pay $7 million to the American Heart Association for such things as public education regarding trans fats and campaigns encouraging the food industry to replace partially hydrogenated oils.

The company also agreed to spend $1.5 million to tell people the status of its trans fat initiative. It will pay $7,500 to BanTransFat.com and $7,500 to class-action plaintiff Katherine Fettke, who will donate the money to charity. And McDonald's will pay the plaintiffs' legal fees.

Joseph declined to comment Friday. In a statement posted on his BanTransFats.com Web site, he said, "McDonald's deserves recognition and credit for having achieved a reduction in the trans fat levels in its chicken products and for working diligently over the last two years to test additional cooking oils."

McDonald's spokesman Walt Riker said the company didn't know when it would find a suitable cooking oil replacement.

"We're still working and testing," Riker said. "We're going to keep trying until we get it right."

Other nutrition advocates said the McDonald's settlement signals how seriously the fast-food industry is taking the public's concern about trans fats.

"Wow, I'm impressed," said Marion Nestle, New York University professor of nutrition.

"Every fast food company, their lawyer, their executives are trying to figure out how to get positioned in this obesity epidemic," said Nestle, author of "Food Politics: How the Food Industry Influences Nutrition and Health." "Nobody wants to be the company that is producing food that nobody wants to eat."

Michael Jacobson, executive director of the Center for Science in the Public Interest, called the settlement "a perfect example of how litigation can motivate food companies to change their practices for the better."

State Sen. Debra Bowen, D-Marina del Rey (Los Angeles County), who has sponsored several pieces of nutrition legislation, said, "It was good to see McDonald's feet held to the fire about its promise."

She hopes the settlement will enable more people to learn about the dangers of trans fats.

"This stuff is bad news, and there's still many, many people out there who don't know much about trans fats," Bowen said.

The American Heart Association advises that healthy people over age 2 limit their intake of saturated fats and trans fats to less than 10 percent of total calories. The organization says trans fats can lead to "higher LDL blood cholesterol levels, which increases fatty buildups in the arteries and raises the risk of heart attack and stroke."

The settlement is another big public splash for Joseph in his battle against trans fats.

In May 2003, Joseph made international news when he sued Kraft Inc. to stop the sale of Oreos to California children because the cookies were high in trans fats. Two weeks after an ensuing flood of publicity, Joseph dropped the suit, saying he had accomplished his goal of raising public awareness about trans fats.

Recently, after his organization persuaded 18 restaurant owners in Tiburon to use trans fat-free cooking oil for frying, the group dubbed the Marin County town "America's first trans fat-free city."