Diacetyl Exposure

Diacetyl exposure may lead to life-threatening lung disease

Inhaling diacetyl, which can be used as a synthetic flavoring agent to mimic the taste of butter, can promote the deadly lung disease bronchiolitis obliterans. Better known as “popcorn lung” for its association with several microwave popcorn plant workers who developed the disease in the early 2000s, bronchiolitis obliterans clogs small air pathways in the lungs and forms scar tissue that diminishes breathing. It is treatable only by lung transplant.

Diacetyl enters the body when a person inhales vapors, droplets of spray or dust containing the chemical. The chemical causes inflammation, scarring and constriction of the bronchioles (tiny airways in the lungs). The constriction causes a loss of lung function and can be fatal.

Symptoms of obliterative bronchiolitis include:

    Exposure to diacetyl may cause

  • stinging or burning in the eyes
  • skin irritation or rash
  • dry cough
  • shortness of breath
  • sore throat

The disease is irreversible. In severe cases patients may be placed on a lung transplant waiting list. There are 4,000 new cases of obliterative bronchiolitis diagnosed each year.

Industries Affected

Industries whose employees are at risk of diacetyl exposure are flavor and food production facilities. Any type of “artificial sweetener” may be made with diacetyl.

  • E-cigarette / Vaping cigarette flavorings
  • Microwave popcorn
  • Potato Chips
  • Corn chips
  • Crackers
  • Cookies
  • Chocolate
  • Cocoa-flavored products
  • Candy
  • Gelatin deserts
  • Flour mixes
  • Flavored syrups
  • Prepackaged frosting
  • Sauces
  • Soft Drinks
  • Chewing gum
  • Ice cream
  • Flavoring agent for coffee
  • Beer and wine (because it is a natural product of alcohol fermentation).
  • Diacetyl is the main flavoring agent in margarine, shortening, oil sprays and most other artificially flavored butter substitutes. Pam is an example of a cooking spray that used diacetyl, although its manufacturer removed the chemical in 2007.

Diacetyl also is used for animal feed flavoring and is used in the baking industry.

Coffee industry faces particular danger

In addition to the dangers of diacetyl use in flavored coffees, recent research also has indicated that workers who roast, grind, package and serve coffee are at risk of diacetyl exposure. Tests have shown that diacetyl and other potentially deadly chemical occur in extremely high concentrations as a natural part of the coffee roasting and grinding process.

Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted its first study at Madison, Wisconsin-based Just Coffee last July, testing air space in a number of settings and situations. They found extremely high concentrations of diacetyl and its equally toxic molecular cousin 2,3 pentanedione throughout the facility, which doesn’t use artificial flavorings in its coffee.

Results showed that Just Coffee workers were typically exposed to 7 parts of diacetyl per billion. The Centers for Disease Control and Prevention (CDC) sets exposure limits at 5 parts per billion. Diacetyl concentrations inside storage bins containing roasted beans were the highest, with 7,000 parts per billion. That finding prompted the CDC to explicitly warn workers to refrain from sticking their heads inside containers or hover in their presence too long.

Researchers also confirmed that the storage bins contained high levels of carbon monoxide and carbon dioxide, which in high enough concentrations can lead to serious illness and death.