December 23/Tulsa, OK/Tulsa World-- More than five years after scientists began linking a flavoring chemical in microwave popcorn to a deadly lung disease in popcorn factory workers, the nation's top seller of microwave popcorn said it has removed the chemical from all its popcorn.

Food giant ConAgra Foods said it removed the chemical, called diacetyl, from Orville Redenbacher and Act II microwave popcorn brands and reformulated the flavors. The new popcorn already is on some store shelves and should be available everywhere in January, said ConAgra spokeswoman Regina DeMars.

The country's other leading makers of microwave popcorn -- General Mills, American Pop Corn Co. and Weaver Popcorn Co. -- said they, too, had removed diacetyl from their recipes.

Weaver Popcorn said it was the first to remove diacetyl back in August and has since received numerous calls and e-mails from customers applauding the move.

None of the companies would disclose the ingredients in the reformulated versions. ConAgra and American Pop Corn, which makes Jolly Time, would say only that they reworked the other existing ingredients.

"It was a very extensive process," DeMars said. "We changed the balance of flavors."

General Mills, which sells Pop Secret, said it removed diacetyl in October but would not say what chemical, if any, it used to replace diacetyl.

"Taste was the most important factor," said company spokesman Tom Forsythe.

Diacetyl is found naturally in low concentrations in many foods such as butter but is artificially produced in plants across the country. Foodmakers like it because it helps produce a rich, buttery taste.

In 2001, diacetyl was linked to a severe lung disease called bronchiolitis obliterans in workers at a microwave popcorn plant in Missouri. It has been tied to three deaths and serious illness in hundreds of people. Juries have awarded $50 million to injured workers and their families. So far, doctors have not found a way to reverse the symptoms.

Calvin Harper, a Milwaukee man who worked with diacetyl at a local flavoring plant for 15 years, said he was glad to hear of the changes in microwave popcorn recipes but cautioned that the chemical is still used in many other snacks and candies.

"This doesn't mean it's gone," Harper said.

Harper suffered injuries to his eyes from exposure to diacetyl and underwent testing last week for lung and other breathing-related problems.

While much of the concern about diacetyl has centered on factory workers, in September, one of the nation's leading lung doctors reported finding a possible link between lung disease and heavy consumption of microwave popcorn. A Colorado man who ate two bags a day for more than 10 years showed symptoms similar to those found in factory workers.

David Michaels, a professor of environmental and occupa tional health at George Washington University who has followed the issue and pushed for federal regulation, said the move is a step in the right direction, but he is worried that whatever might be used to replace diacetyl or the changes in concentrations of pre-existing ingredients still could pose problems.

"It's very important OSHA (the Occupational Safety and Health Administration) move quickly," Michaels said.

From the January 7, 2008, Prepared Foods e-Flash