In 2004, the California Legislature gave foie gras producers seven years to find a humane way to create the duck liver delicacy without forcing food down the birds' throats.

With the law set to take effect the July 1, some of the state's top chefs on Monday were attempting to overturn it. A hundred have signed a petition saying they want to keep the sale of foie gras legal and establish new regulations for raising the birds. They are visiting with their representatives trying to accomplish an uphill task: finding someone to sponsor a bill to repeal it in time.

Their 11th-hour attempt has ruffled the feathers of the ban's original sponsor.

"I gave them seven years — seven years, and I shouldn't have — and now they're all going, 'Oh my God, I just don't know how we're going to survive,'" said John Burton, the former president pro tem of the state Senate who is now the state Democratic Party Chairman. "I'm so infuriated with the bad faith going on here that words cannot describe it."

Burton's bill banned the "inhumane practice" of force-feeding ducks and geese as well as the sale of foie gras in California. Burton initially agreed to delay implementation of the bill because the state's sole producer had asked for time to find a more humane way to engorge the birds' livers to keep the dish on menus.

"It's been a rough couple of years for restaurants because of the economy," said Nathan Ballard, spokesman for the group that delivered the petition to the office of Assembly Speaker John Perez on Monday. "This is one more blow to the restaurant industry in California. Chefs don't want to see it go into effect."

Perez's office had no comment on the issue.

Foie gras, French for "fat liver," is created by the funnel-forced ingestion of large amounts of feed into the duck's esophagus. Eventually the liver grows to more than 10 times its normal size.

The chefs who opposed the ban — most from the San Francisco Bay Area — also are using an animal welfare argument. Calling themselves the Coalition for Humane and Ethical Farming Standards, or CHEFS, they are asking the state to set standards for foie gras production that would include audits by animal welfare experts, cage-free birds, hand feeding by methods that don't impair breathing, and limits on fattening. They say that if foie gras is outlawed, people will buy it on the black market.

Sonoma Foie Gras founder Guillermo Gonzalez, whose company is California's only foie gras producer, said his 26-year-old business has been unfairly maligned in the name of animal rights. His birds, Gonzalez said, roam free for most of their lives and are individually fed by the same feeder twice a day for the last two weeks of their lives.

"I do not believe that foie gras farming, when done correctly, is harmful or hurtful to the animal," Gonzalez said. "I believed then, as I believe today that our farming techniques would be considered humane under any unbiased scientific scrutiny."

He said that when Burton first introduced his bill, there was talk of a compromise in which the state would fund research "validating or negating whether the methods used in our foie gras production were acceptable." But the funds never were attached to the legislation, and "as a result, there was no study, and therefore, no way to exonerate my business."