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NIOSH Respiratory Diseases Research Program

Evidence Package for the National Academies' Review 2006-2007

NIOSH Programs > Respiratory Diseases > Evidence Package > 9. Respiratory Disease HHEs and Technical Assistance

9.3 Flavoring-Related Lung Disease

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HETA # 2000-0401-2991 Gilster-Mary Lee Corp. Jasper, MO (A9-22)
HETA # 2001-0474-2943 American Popcorn Co. Sioux City, IA (A9-23)
HETA # 2002-0408-2915 Agrilink Food Popcorn Plant, Ridgeway, IL (A9-24)
HETA # 2003-0112-2949 ConAgra Snack Foods Marion, OH (A9-25)


Bronchiolitis obliterans related to artificial butter flavorings inhalation came to our attention through a technical assistance request from the Missouri Department of Health and Senior Services, which had received medical reports of severe obstructive airways disease among eight former workers of a small microwave popcorn plant. Four were on lung transplant lists. This condition has caused severe lung disease and death. Economic impact on flavoring manufacturers has been high, with multi-million dollar awards and settlements.


We established that excess respiratory disease existed within microwave popcorn plants by comparing symptom, pulmonary function, and physician diagnosis data to national prevalence data and by examining the distribution of abnormalities within plant job and area subgroups. To determine the likely etiology of the lung disease, we combined the findings from health surveys and medical testing for objective abnormalities with flavoring chemical measurements for jobs within the plants, and examined exposure-response relationships. Exposure to diacetyl, a major component of artificial butter flavorings, was used as a marker of exposure to the complex artificial butter flavoring mixture.

In two of six companies that we investigated through the HETA program, pulmonary function abnormalities were documented in about 25 percent of the workforces. As detailed in chapter 4.2d, cases of disabling irreversible lung disease have now been recognized in five of six microwave popcorn plants, flavoring manufacture, other food production, and diacetyl manufacture.

As interventions were introduced to lower exposures, we studied workers over time to demonstrate that disease abnormalities stabilized in those affected and that new workers were at low risk as exposures were reduced to levels below the limits of detection. Our documentation resulted in additional requests for hazard evaluations from companies, state health departments, and workers, and further investigations allowed us to make generalizations across the industry about high risk jobs, exposures associated with disease risk, the likely importance of peak exposures, and the relative exposures associated with powdered flavorings and liquid/paste flavorings in the laboratory and in one plant.

Outputs and Transfer

As detailed in chapter 4.2d, the hazard evaluation investigations resulted in company-specific reports, a NIOSH Alert (Preventing Lung Disease in Workers Who Use or Make Flavorings; A4-74) disseminated to more than 6000 companies, two workshops for the Flavoring Extract Manufacturers Association (A4-73, A4-76), meetings with the American Popcorn Board, the Flavoring and Extract Manufacturing Association and interested medical professionals; stimulation of animal toxicology research at NIOSH and the NTP of the NIEHS, and 11 applied research publications (A9-26) of which three are cited here (6-8, A4-79, A4-80, A9-27).

Intermediate Outcomes

Investigations within plants have demonstrated lowering of hazardous exposures apart from rooms for flavorings transfer, which likely requires the engineering of closed systems. One company is attempting a demonstration of whether less costly exhaust ventilation is feasible. The large companies manufacturing microwave popcorn have now protected most of their employees from flavoring exposure.

That this work has influenced others is evidenced by requests from groups consisting of labor unions, public health experts, and academics to California-OSHA and Federal OSHA to develop emergency temporary standards for diacetyl.

Other intermediate outcomes are as detailed in chapter 4.2d, which describes actions taken by others as a result of this work.

What’s Ahead

Activities for RDRP in general are detailed in chapter 4.2d. With regard specifically to the HETA program, several activities are currently in progress. One HHE request resulted in an evaluation of a Montana popcorn-popping operation. A technical assistance request from California-OSHA and the California-Department of Health resulted in an investigation of a flavorings manufacturing plant in California that was the site of a documented case of flavorings-induced bronchiolitis obliterans. Finally, California-OSHA has requested technical assistance in assessing flavorings exposures and developing potential control technology solutions across the California flavorings manufacturing industry. RDRP investigators will complete these HETAs and take on others as requested as part of the effort to eliminate this disease.