By Associated Press, 10/04/01

JASPER, Mo. -- Workers at a microwave popcorn plant have developed a rare lung disease that investigators believe was caused by breathing vapors from artificial butter flavoring.

Four of the workers need lung transplants.

Altogether, eight employees at the Gilster-Mary Lee Corp. plant in Jasper have developed bronchiolitis obliterans -- a type of irreversible lung damage -- after being exposed to the flavoring while mixing and packaging popcorn, the National Institute for Occupational Safety and Health said.

An additional 21 of plant's 117 workers show signs of lung problems, but the cause is still under investigation.

Doctors who investigated for NIOSH said the problem appears to be limited to workers who inhaled large amounts of butter flavoring vapors wafting from big vats. They said there is no danger to people who microwave the popcorn and eat it at home.

Gilster-Mary Lee said the popcorn is sold under a variety of store labels.

Dr. Kathleen Kreiss, who is participating in the NIOSH investigation, said the agency now wants to know whether workers at other microwave popcorn plants around the country are being affected in the same way.

So far, one case has surfaced in Nebraska that resembles bronchiolitis obliterans, Kreiss said.

Another important question, she said, is what ingredient in the flavoring may have triggered the disease.

Dr. Eduardo Simoes, a Missouri state epidemiologist, said investigators suspect a chemical in the butter flavoring, possibly diacetyl. Tests on rats should identify the cause, he said.

The federal investigation began in August 2000 after a doctor in Kansas City, Allen Parmet, who handles occupational health problems, saw six patients with the disorder at once, all from the same small area of Missouri. That was four more than he had seen in his entire career.