Flavorings found in food products often contain complex mixtures of natural and manmade ingredients. Depending on the flavoring and the food product manufacturing process, workers in factories and manufacturing plants may be exposed to hazardous flavorings or flavoring ingredients in the form of chemical vapors, dusts, or sprays.

Recent research has focused on the release of harmful chemical vapors at microwave popcorn packaging plants. Studies have revealed the occurrence of severe lung disease in workers at these plants. More specifically, a chemical called diacetyl, found in butter flavoring mixtures, may be causing bronchiolitis obliterans, an uncommon lung disease characterized by fixed airway obstruction.

In September 2007, a number of microwave popcorn manufacturers announced that they are making efforts to remove the chemical food additive diacetyl from their products, and ABC News reported the first known case of bronchiolitis obliterans (also called "popcorn lung") in a consumer who ate large quantities of microwave popcorn.

More Information:
• FindLaw's Common Law Blog: Chemical in Microwave Popcorn Poses Risk
• ABC News: Popcorn May Cause Lung Disease

Diacetyl

Diacetyl (2,3-butanedione) is a chemical that has been used to add a butter-like flavor to food products, including microwave popcorn.

Animal studies of exposure to butter flavoring vapors have shown airway injury in rats after acute inhalation of these vapors. While the studies show that the vapors are capable of causing severe airway injury in laboratory animals, a causal relationship between diacetyl exposure and the development of bronchiolitis obliterans has not been firmly established.

Bronchiolitis Obliterans

Bronchiolitis obliterans is an uncommon lung disease characterized by fixed airway obstruction. When inflammation and scarring occur in the smallest airways of the lung, it can lead to severe and disabling shortness of breath.

There are many known causes of this disease -- including inhalation of certain chemicals, certain bacterial and viral infections, organ transplantation, and reactions to certain medications. Other gases that might cause bronchiolitis obliterans in occupational settings or in other environments include nitrogen oxides, sulfur dioxide, chlorine, ammonia, phosgene, and other irritant gases.

Symptoms Associated with Flavoring Chemical Exposure

Up until recently, doctors thought the symptoms associated with flavoring exposure were due to asthma, chronic bronchitis, emphysema, pneumonia, or smoking. These symptoms include cough (without phlegm) and shortness of breath on exertion. Symptoms typically do not improve when the worker spends time away from the factories and plants that produce, use, or process flavoring chemicals. Symptoms range from mild to severe, and are usually gradual in onset and progressive (although severe symptoms can occur suddenly).

Other symptoms associated with flavoring exposure include fever, night sweats, and weight loss, as well as eye, nose, throat, and skin irritation. In some cases, chemical eye burns have required medical treatment.

While there may be a gradual reduction of cough years after exposure, shortness of breath on exertion persists. Severe lung disease may require a lung transplant.

Hazardous Exposure Elimination and Prevention

The following is a summary of the National Institute for Occupational Safety and Health's (NIOSH) recommendations on how employers can prevent hazardous exposure to flavoring chemicals. For a full description of NIOSH's recommendations, click here . Also, see Preventing Lung Disease in Workers Who Use or Make Flavorings .

• Substitution: Employers can substitute a less hazardous material if feasible and definitive. In other words, changes should only be made if an adequate substitute exists and if its possible health effects are well understood. As a general rule, there is less of a risk with the release of less volatile chemicals or respirable powders into the air.

• Engineering Controls: Employers can eliminate the handling of open containers of flavorings when placing them into mixing tanks; use adequate ventilation systems; apply adequate temperature controls to minimize the emissions of volatile chemicals into the air; and isolate processes wherein flavorings and their ingredients are openly handled.

• Administrative Controls: Employers can establish and enforce work practices that limit the release of chemicals and dust into the air when flavoring ingredients are handled. This can be accomplished by tightly sealing containers with unused or residual amounts of these chemicals as well as maintaining good general housekeeping in areas where these chemicals are handled.