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Occupational Health Branch

Flavoring-Related Lung Disease (Bronchiolitis Obliterans)

Bronchiolitis obliterans (BO) is a severe lung disease that has been identified in workers who make microwave popcorn and in food flavorings, and more recently, in workers who roast coffee. This disease can cause permanent impairment or death.

The main symptoms of flavoring-related lung disease are a persistent cough, shortness of breath when using extra energy (such as walking fast or up a slight hill), and wheezing. The symptoms persist when away from work. They can start gradually and get worse over time, or they can suddenly be very severe. A worker may have early disease without any symptoms.

Fixed obstructive lung disease such as BO has been associated with exposure to diacetyl, a butter flavoring ingredient. Diacetyl is one cause of airway damage that might result in BO, but other flavoring chemicals may have the potential to cause BO or contribute to airway damage, including chemicals increasingly used as substitutes for diacetyl.

Companies that use diacetyl or diacetyl-containing flavorings should have a medical surveillance program to monitor their employees' health and lung function. In addition, they should take preventive measures to reduce exposure to diacetyl and other flavoring chemicals. See below for medical guidelines and prevention information.


For Health Care Providers*

Industry-Wide Investigation

Fact Sheets

Laws & Regulations

* Please contact if you are health care provider and need a medical questionnaire for flavoring exposure medical surveillance.
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