What Is Popcorn Lung?
Popcorn lung is the everyday name for obliterative bronchiolitis, a lung disease that the National Institute for Occupational Safety and Health (NIOSH) associates with workplace exposure to diacetyl. NIOSH describes diacetyl and its substitute 2,3-pentanedione as flavoring chemicals used in food flavoring and production, including the microwave popcorn, bakery mix and flavored coffee industries.
The name traces to a microwave popcorn plant. NIOSH says that in August 2000 a health department asked it to investigate obliterative bronchiolitis in former workers of the plant, and that the research that followed found artificial butter flavorings added to popcorn caused disease. NIOSH says the disease, also called constrictive bronchiolitis or bronchiolitis obliterans, causes scarring and constriction in the lung's airways that blocks air movement, and that it cannot be cured. It adds that 2,3-pentanedione has had similar respiratory effects in animal studies.
The documented risk is in workplaces. NIOSH has set recommended exposure limits for both chemicals to reduce the risk of decreased lung function and obliterative bronchiolitis from occupational exposure. On vaping, the CDC lists diacetyl among e-cigarette flavorings, calling it a chemical linked to a serious lung disease, and says some flavorings may be safe to eat but not to inhale because the lungs process substances differently than the gut.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Government sourceNIOSH describes diacetyl and its substitute 2,3-pentanedione as flavoring chemicals used in food flavoring and production, including the microwave popcorn, bakery mix and flavored coffee industries. NIOSH, CDC ↗
- Government sourceNIOSH says workplace exposure to diacetyl has been associated with severe respiratory impairment and with obliterative bronchiolitis, also called constrictive bronchiolitis and bronchiolitis obliterans. NIOSH, CDC ↗
- Government sourceNIOSH says obliterative bronchiolitis causes scarring and constriction in the lung's airways, blocking air movement, and cannot be cured, and that 2,3-pentanedione has had similar respiratory effects in animal studies. NIOSH, CDC ↗
- StudyNIOSH says a health department asked it in August 2000 to investigate obliterative bronchiolitis in former workers of a microwave popcorn plant, and that its later research found artificial butter flavorings added to popcorn caused disease. NIOSH, CDC ↗
- Government sourceNIOSH set recommended exposure limits for diacetyl and 2,3-pentanedione to reduce the risk of respiratory impairment and obliterative bronchiolitis associated with occupational exposure. NIOSH, CDC ↗
- Government sourceThe CDC lists diacetyl among e-cigarette flavorings as a chemical linked to a serious lung disease, and says some flavorings may be safe to eat but not to inhale because the lungs process substances differently than the gut. CDC ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.