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 Gilster-Mary Lee Corp. 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 the 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.
The popcorn is sold under a variety of store labels, according to Gilster-Mary Lee.
Investigators suspect a chemical in the butter flavoring, possibly diacetyl, is causing the damage, said Dr. Eduardo Simoes, a Missouri state epidemiologist. Tests on rats should identify the cause, he said.
Sixteen current and former employees have filed workers' compensation claims against Gilster-Mary Lee, headquartered in Chester, Ill. The 16 also have filed a class-action lawsuit against New York-based International Flavors and Fragrances, which makes the flavorings. The plaintiffs are seeking unspecified damages.
Gilster-Mary Lee and International Flavors did not return calls Thursday.
Dr. Kathleen Kreiss, who is participating in the NIOSH investigation, said Gilster-Mary Lee employees working in affected areas of the plant are now wearing face masks as a temporary measure. She said the company has engineers looking at long-term solutions, which include sealing the vats to contain the vapors.
"We're very pleased by their response to this situation," she said.
Kreiss said NIOSH now wants to know whether workers at other microwave popcorn plants around the country are suffering the same effects. So far, one case has surfaced in Nebraska that resembles bronchiolitis obliterans, she 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.