Popcorn Minus Diacetyl

Manufacturers of microwave popcorn in the U.S. are replacing diacetyl (2,3-butanedione) as the butter-flavor agent in their products because the compound can cause severe obstructive lung disease in workers.

Weaver Popcorn announced at the end of August that it had eliminated diacetyl from its products. Weaver makes about 20% of the microwave popcorn in the U.S. ConAgra Foods, the largest maker of microwave popcorn, including the brands Orville Redenbacher and Act II, tells C&EN that it will eliminate diacetyl from its products in the near future.

Diacetyl exposure has been a concern in microwave popcorn manufacturing facilities since at least 2000, when it was first recognized that some workers had developed lung problems. Investigations by the National Institute of Occupational Safety & Health pointed to diacetyl as the cause, and the agency proposed stricter limits on exposure.

In 2006, several labor unions petitioned the Occupational Safety & Health Administration to set a temporary emergency standard for diacetyl to protect workers, but OSHA has not acted yet.

The possible health impact on consumers is an increasing concern. Cecile S. Rose, acting head of the Division of Environmental & Occupational Health Science of the National Jewish Medical & Research Center, in Denver, wrote a letter to FDA in July describing what may be the first consumer to contract obstructive lung disease from breathing fumes from microwave popcorn packages. FDA permits use of diacetyl as a flavoring and classifies it as "generally recognized as safe."

In 2003, EPA initiated a study of exposure to compounds from microwave popcorn packages. Those data have never been made public, but a spokeswoman for EPA says the results will be published soon.