In the wake of the recent concern over the serious disease called “popcorn worker’s lung,” producers of microwave popcorn have set about to remove the butter flavoring chemical linked to the illness.

Diacetyl, a chemical ingredient found in the buttery flavoring of microwave popcorn, was linked to bronchiolitis obliterans, or popcorn lung, as early as 2001. At that time, medical experts singled it out in workers at an American plant that manufactured microwavable popcorn who had fallen ill.

On Tuesday, the Flavor and Extract Manufacturers Association recommended that microwave popcorn producers who use diacetyl reduce the chemical’s concentration in flavors.

Now, producers of microwave popcorn have announced that they will work to remove diacetyl from their flavoring. Both producers and the association have emphasized that the popcorn itself is safe for consumers.

This comes after reports this week that there may have appeared the first consumer case of popcorn lung.

According to the Associated Press, the three companies that sell Orville Redenbacher, Act II, Pop Secret, and Jolly Time microwave popcorn said they plan to remove diacetyl. These companies are ConAgra Foods Inc., General Mills Inc., and American Pop Corn Co.

Dr. Cecile Rose, director of the occupational disease clinical programs at the National Jewish Medical and Research Center in Denver sent letters to four federal regulatory agencies this week, describing the unexpected consumer case of popcorn lung.

The patient, a furniture salesman from Colorado, had reportedly been eating two or three bags of microwave extra-butter-flavored popcorn each day for ten years. Dr. Rose and her colleagues measured the levels of diacetyl in his house and found they were similar to those found in microwave popcorn plants.

They found that the man enjoyed popcorn so much he actually inhaled the fragrance emanating from the hot bags. Dr. Rose asked him to stop eating popcorn and 6 months later, he had lost 50 pounds while his lung function had improved slightly.

“This is not a definitive causal link, but it raises a lot of questions and supports the recommendation that more work needs to be done,” Dr. Rose said.