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Flavoring-related Lung Disease

Background and Purpose

In 2002, the National Institute for Occupational Health and Safety (NIOSH) reported that workers at a microwave popcorn plant had developed bronchiolitis obliterans, a serious and life-threatening lung disease.  NIOSH concluded that inhalation of butter flavor was the likely cause of disease.  Research has shown that the chemical diacetyl, an ingredient in butter and other food flavorings, causes severe lung damage in animals.  In 2004, a California worker who made food flavorings using diacetyl was found to have bronchiolitis obliterans.  Several additional workers in flavoring companies have been diagnosed with the disease since then, and more are suspected.  Since the first case occurred OHB has worked with Cal/OSHA and other partners to respond to this newly recognized hazard and to prevent other workers from getting this disease.

The purpose of the OHB project was to determine how widespread diacetyl-related lung disease is in California, to recommend ways to prevent the disease in workers who make or use food flavorings, and to ensure that affected employers, workers, and health care providers have the information they need to recognize and prevent future cases.


To address this serious hazard OHB:

  • Worked with Cal/OSHA Consultation Service to evaluate respiratory health and chemical exposures at California companies that make flavorings;
  • Convened a group of medical experts to develop guidelines doctors can use to follow flavoring workers and detect lung disease related to their work;
  • Conducted an outreach campaign to employers, workers, and health care providers using our new HESIS Health Hazard Alert on diacetyl  (butter flavoring chemical); and
  • Worked with Cal/OSHA and others to develop an occupational health standard on diacetyl.
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Last modified on: 8/23/2016 9:02 AM