Diacetyl is a chemical used to add flavor and aroma to food and other products. Some workers who breathe diacetyl on the job have become disabled or have died from severe lung disease. Some diacetyl substitutes also may cause harm.

OSHA strongly recommends that all flavoring and food manufacturers review and consider implementing applicable recommendations regarding engineering and work practice control measures, medical surveillance, workplace monitoring and use of appropriate personal protective equipment to minimize each worker's exposure to these flavoring substances.

“Illnesses arising from diacetyl exposure continue to place workers at risk,” said Assistant Secretary of Labor for Occupational Safety and Health Dr. David Michaels. “It is vital that employers use preventive measures to protect their workers from the harmful effects caused by these dangerous chemicals.”

Currently, OSHA does not have permissible exposure limits for most flavoring substances, including diacetyl. However, flavorings manufacturing facilities are subject to other applicable OSHA mandatory standards including Respiratory Protection and Hazard Communication. Based on concerns for workers’ safety and health, OSHA is updating its National Emphasis Program on Microwave Popcorn Plants to include diacetyl substitutes and has initiated rulemaking on occupational exposure to diacetyl and food flavorings containing diacetyl.

For more safety and health information on diacetyl and other food flavorings, visit OSHA’s Safety and Health Topics page on Lung Disease Related to Butter Flavorings Exposure and the Hazard Communication Guidance for Diacetyl and Food Flavorings Containing Diacetyl.