NIOSH Releases New Fact Sheet on Diacetyl Exposure

NIOSH recently compiled a fact sheet on lung disease that can result from exposure to flavoring chemicals containing diacetyl.

Severe obstructive lung disease has been identified in people who work with flavoring chemicals containing diacetyl, including butter flavoring. Cases of severe lung disease have occurred in microwave popcorn plants and flavoring production plants. Lung biopsies in some affected people have shown the presence of a rare condition; constrictive bronchiolitis obliterans (also referred to as constrictive bronchiolitis, obliterative bronchiolitis, and bronchiolitis obliterans). In some workers, fixed airways obstruction has been severe enough to be fatal.

Who is at risk?

Workers who make, use, or work near flavoring chemicals containing diacetyl may be at risk. Settings where these exposures may occur include:

  • Flavoring plants
  • Microwave popcorn plants
  • Commercial and retail bakeries
  • Snack food and candy plants
  • Dairy products and packaged vegetable oil plants (e.g., margarine, cooking oil)
  • Other flavored food production plants

While exposures in the flavoring industry and in microwave popcorn production have caused severe lung disease in some workers, the degree of risk to workers from exposures in other work settings is currently unknown.

Symptoms are not present in all cases. When present, symp¬toms can range in severity. The main respiratory symptoms experienced by workers include:

  • Cough (usually without phlegm)
  • Shortness of breath on exertion
  • Wheezing

Other symptoms experienced by some workers include:

  • Fever, night sweats, or weight loss
  • Frequent or persistent eye, nose, throat, or skin irritation

In cases of flavoring-related lung disease, respiratory symp¬toms do not typically improve when the worker goes home at the end of the workday, on weekends, or on vacations. The symptoms often have a gradual onset but can occur suddenly. Work-related exposure to butter flavoring chemicals might also lead to asthma or exacerbate pre-existing asthma.

Medical testing may include the following:

  • Spirometry most often shows an obstructive pattern of ventilatory impairment that does not improve after bronchodilators and sometimes shows a restrictive pattern of ventilatory impairment. Careful comparison of spirometry test results over time is important to identify potentially concerning declines in lung function.
  • Lung volume assessments are consistent with hyperinflation.
  • Carbon monoxide diffusing capacity measurement is generally normal, especially early in the disease.
  • Chest X-rays are usually normal but may show hyperinflation.
  • High-resolution computerized tomography scans of the chest at full inspiration and expiration often reveal heterogeneous air trapping on the expiratory view and may demonstrate mosaic attenuation, bronchial wall thickening, cylindric bronchiectasis, and/or scattered ground glass opacities.
  • Lung biopsies are not generally required for diagnosis, but may reveal evidence of constrictive bronchiolitis obliterans. Sometimes the term clinical bronchiolitis obliterans is used for patients who have medical test findings consistent with the disease constrictive bronchiolitis obliterans but do not have confirmatory biopsy results.

Workers with flavoring-related lung disease should be removed from further exposure and relocated within the facility to areas where they will not be exposed to diacetyl or similar flavoring chemicals.

Remind patients of the importance of:

  • Keeping flavoring containers tightly closed when not in use to prevent the contents from getting into the air.
  • Reading and understanding labels on containers and material safety data sheets for substances that they are exposed to in the workplace.

Encourage patients to talk to their supervisors about:

  • Training on hazard identification, procedures for safe handling of flavoring chemicals, and symptoms of flavoring-related lung disease.
  • Exposure control methods (e.g., ventilation, isolation) and work practices (e.g., standard procedures for cleaning the workplace and for handling and storing flavoring chemicals).
  • Wearing respirators (protective breathing equipment) and other personal protective equipment (e.g., gloves, eye goggles) to reduce exposures.

Click here to read to entire fact sheet.

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