Who doesn’t love the taste of butter-flavored popcorn?  But how many of us are aware of “popcorn lung disease” or “popcorn workers lung,” caused by exposure to a butter-flavoring chemical called diacetyl, and possibly mixed with other flavorings?   The National Institute for Occupational Safety and Health (NIOSH), has, and continues to investigate the occurrence of severe lung disease in employees in microwave popcorn packaging plants and flavorings manufacturing facilities for several years.  Their reports show that many employees at microwave popcorn plants suffer from fixed airways obstruction, some consistent with bronchiolitis obliterans, and other respiratory illnesses.  The type of lung damage that many employees have suffered is irreversible, and some have died from it.  Numerous lawsuits have been settled by those who have been affected.  NIOSH also reported that employees at microwave popcorn plants and a flavorings manufacturing facility experienced eye, nasal, and/or upper respiratory irritation and/or burns.   

Around September, 2007, several well-known popcorn manufacturers announced that they would remove the flavoring chemical.  In October, 2009, OSHA launched a National Emphasis Program to reduce and eliminate the hazards associated with chemical exposures from diacetyl, the prominent chemical ingredient in butter flavorings.  Those workers who work around vats containing these mixtures, as well as the ones who package the microwave popcorn should have adequate protection from breathing these harmful vapors in their work environment.  Other food products that may use this flavoring include candy, potato chips, and pound cakes.  

NIOSH has issued the following recommendations for reducing employee exposure to potentially dangerous flavoring chemicals:

  • Use engineering controls such as closed systems, isolation, ventilation booths, or local exhaust ventilation.  Simple exhaust hoods can dramatically reduce exposure.
  • Train employees on all potential hazards and ensure that they understand proper procedures and use of engineering controls.  It is critical that engineering controls are effective in protecting workers.
  • Good housekeeping and work practices that minimize exposure are carried out through administrative rules.
  • Proper personal protective equipment must be used.  Suitable respirators, such as NIOSH-certified respirators with organic vapor cartridges combined with particulate filters would provide minimum level of protection.  Teflon, Tychem, or butyl rubber gloves and aprons to reduce skin contact with ketones (diacetyl).  Eye protection is  needed, as well.
  • Workers exposed to flavoring chemicals should have their lung function checked by spirometry on a regular basis.
  • Monitor occupational exposures and the state of workers’ health often.
  • All workers should know the MSDS information regarding the chemicals they are exposed to. 

NIOSH states: “Even if substances are safe to eat – ‘generally recognized as safe’  as determined by the Food and Drug Administration, they may still be harmful to breathe in the forms and amounts to which food and chemical industry workers may be exposed.  How much exposure that people have to diacetyl and other inhaled flavoring chemicals is the important issue in determining the risk for lung disease.  It would be hard to compare the risk to consumers to that of the workers.  Even though there is little to suggest significant risk to normal consumers, a sensible precautionary approach should be taken.  Cooking or popping of products containing diacetyl and other butter flavoring chemicals should be done in an area with adequate exhaust ventilation, in order to remove vapors.  Microwave popcorn bags should be allowed to cool before they are opened, which will also decrease exposure to vapors.  Flavoring mixtures are often complex and contain both natural and manmade substances.  There is much to be learned about the potential health effects of the individual component materials and how they interact when combined.” 

I checked the box of butter-flavored popcorn in my pantry and it doesn’t list diacetyl; however, it does state “artificial flavors” in the ingredients.  That’s food for thought, isn’t it?