'Popcorn Lung' Erupts in Flavor Industry

ATLANTA, April 27 -- Bronchiolitis obliterans -- called "popcorn lung" when it affects workers making butter flavoring for microwave popcorn -- has been identified in other sectors of the flavoring industry.

Seven workers in four California flavor manufacturing plants have been found to have the condition, according to the CDC here.

Also, another 22 workers with obstructive lung abnormalities detected by state-ordered spirometry are being medically evaluated, the agency said today in Morbidity and Mortality Weekly Report. "Flavorings are not known to put consumers at risk for lung disease," the CDC report said.

Bronchiolitis obliterans is "a rare and life-threatening form of fixed obstructive lung disease," the CDC said, and can be caused by exposure to noxious gases in the workplace.

It has also been linked to inhaling powdered diacetyl, a compound used in making butter flavoring for microwave popcorn and also in other commercial flavorings.

"The prognosis is generally poor," said Mark Rosen, M.D, of the North Shore Long Island Jewish Health System, president of the American College of Chest Physicians "although some patients might be successfully treated with medications to depress the immune system."

In general, though, "the treatment would be a lung transplant most of the time," said Dr. Rosen, who was not involved with the report.

"In bronchiolitis obliterans," Dr. Rosen said, "the small airways develop an inflammatory reaction, such that they close off, they become scarred, and they become filled with proteinaceous material."

The current findings came after California health and occupational safety officials became aware of two cases in separate flavor manufacturing companies and started an investigation.

The first case, the agency said, involved a 29-year-old with no history of smoking, lung disease, or respiratory symptoms, who in 2003 developed progressive shortness of breath during exertion, decreased exercise tolerance, intermittent wheezing, left-sided chest pain, and a productive cough.

The symptoms began two years after he started work as a flavor compounder, a job that involved measuring diacetyl and other compounds.

The workplace did not have effective ways of limiting exposure to the chemicals, the CDC said, and although the man reported wearing a paper dust mask, it had not been properly fitted.

By 2004, the man had stopped working because of his respiratory symptoms. He had severe shortness of breath after walking 10 to 15 feet. A high-resolution computed tomography scan of his chest showed cylindrical bronchiectasis in the lower lobes, with scattered peribronchial ground-glass opacities.

Spirometry showed severe obstructive lung disease, with a forced expiratory volume in 1 second (FEV₁) of 28% of the predicted normal value. There was no bronchodilator response. His lung diffusing capacity was normal.

The second case involved a 40-year-old woman who again was a non-smoker with no history of lung disease or respiratory symptoms. She developed nasal congestion and cough after five years in a job where she mixed diacetyl and other ingredients to make artificial butter flavoring.

Again, the workplace did not have effective ways of preventing exposure and although the woman wore a paper dust mask, it had not been properly fitted.

The woman had progressively worsening shortness of breath on exertion, decreasing exercise tolerance, and a nonproductive cough. In November 2005, a CT scan of her chest showed several small areas of patchy ground-glass opacities throughout the lungs.

A month later, she stopped work because of symptoms. Spirometry showed severe obstructive lung disease, with an FEV₁ of 18% of the predicted normal value, without bronchodilator response. Her diffusing capacity was normal.

California health officials reached all 28 flavor-makers in the state and initiated a program of spirometry screening for workers. By March 1, 2007, spirometry results for 419 of approximately 750 employees in the 28 companies had been received.

As a result of that program, five additional workers were found to have fixed obstructive lung disease, the CDC said.

Reported symptoms cough, wheezing, or shortness of breath on exertion. FEV₁ ranged from 17% to 44% of predicted normal value for age, height, race, and sex. FEV₁ values did not improve after bronchodilator administration.

The companies have been required to reduce employee exposure to diacetyl and other flavoring ingredients using engineering controls, such as effective ventilation, and protective respiratory measures, such as the use of respirators with particulate filters and cartridges for protection against organic vapors.