Click here to listen to Newsradio 620 WTMJ's Jay Sorgi report on the changes microwave popcorn brands are making due to the chemical diacetyl.

The nation's biggest popcorn maker is changing some of the flavor in order to remove the risk of lung disease.

ConAgra Foods makes Orville Redenbacher and Act II popcorn. It's put the chemical diacetyl in its popcorn to get that buttery taste, but the company found that some of its workers were getting bronchiolitis obliterans, a deadly lung disease, from working with the stuff.

So, ConAgra is removing diacetyl and cooked up a new and safer recipe for its popcorn.

"We want to assure our consumers they can continue to enjoy their favorite popcorn with complete confidence," said ConAgra's Stan Jacot, who oversees popcorn marketing for the company.

Many other popcorn makers are removing the chemical as well, and they plan to have the newer versions of their product out by January.

Calvin Harper, who's from Milwaukee, worked with diacetyl. He tells the Journal Sentinel that many other snack and candy makers still use diacetyl.

Diacetyl occurs naturally in foods such as butter, cheese and fruits, and the FDA has approved its use as a flavor ingredient.

The Associated Press contributed to this report.

Correction: Earlier online versions of this story made reference to a popcorn recall.  There has not been a recall of microwave popcorn products.