Microwave Popcorn and Decreased Lung Function

by Sloane Miller Patient Advocate

You won't look at popcorn and butter the same way again.

One of the great pleasures of seeing a movie used to be getting popcorn with butter. In New York City, when I was a kid, the RKO theaters had real butter for their freshly popped popcorn, not the manufactured yellow goo. But I also remember going to other movie theaters and pumping out the yellow colored, butter flavored slime, happily, onto our popcorn -- the more the better. I found this 20-year-old New York Times article rating the best popcorn at the city's then-existing movie houses. Many of them are now shuttered, but it's still fun to read.

What's less fun are two recent stories about diacetyl and bronchiolitis obliterans. Never heard of those? Me neither.

According to the U.S. Department of Labor's Occupational Safety & Health Administration or OSHA: "Diacetyl (also called butanedione or 2,3-butanedione, molecular formula C4H6O2) is a natural byproduct of fermentation and is also synthesized by chemical manufacturers. Diacetyl gives butter and certain food flavorings a distinctive buttery flavor and aroma. Food flavorings containing diacetyl are used in microwave popcorn and other snack foods, pet foods, candies, baked goods, and other food products."

Guess where you find this product? Everywhere, especially movie popcorn, microwave popcorn and at your local greasy spoon.

Diacetyl becomes potentially hazardous when it's heated. It gives off a vapor that's proving to cause lung dysfunction in workers who are exposed over long periods of time. These workers would be line cooks who use the butter-flavored oil when griddling your morning pancakes, or, in the case of one man, someone who's been eating microwave popcorn two times a day for more than 10 years. Doctors think what may have been the exact point of contact is when he opened the just popped bag of popcorn and inhaled the steam rising from the product with -- you guess it -- heated diacetyl.

Last September, the New York Times filed this article:

"A fondness for microwave buttered popcorn may have led a 53-year-old Colorado man to develop a serious lung condition that until now has been found only in people working in popcorn plants."

The culprit: diacetyl.

"Heated diacetyl becomes a vapor and, when inhaled over a long period of time, seems to lead the small airways in the lungs to become swollen and scarred. Sufferers can breathe in deeply, but they have difficulty exhaling. The severe form of the disease is called bronchiolitis obliterans or "popcorn workers' lung," which can be fatal."

Luckily for this man, on the advice of his doctor, he stopped eating microwave popcorn and within six months had lost 50 pounds and regained his full lung function.

The Seattle Post Intelligencer reported on this in December 2007:

"Hundreds of brands of cooking oils, butter substitutes and sprays use diacetyl to provide or enhance the flavor of butter... Occupational health specialists have said that repeated exposure to diacetyl has led to the deaths of at least three workers, destruction of the lungs of scores more and sickened hundreds of others who worked in plants that produce flavorings, microwave popcorn, candy, beverages, oils and other products...

"It is very important to protect cooks from exposure to diacetyl as (bronchiolitis obliterans) is a very serious lung problem that cannot be reversed," said Dr. Robert Harrison, professor of occupational medicine at the University of California-San Francisco.

Factory workers and line cooks aren't as lucky as the man in the New York Times story, often because they don't report the illness for fear of losing their job. However, recently several hundred families filled lawsuits:

"More than 500 workers from the popcorn and flavoring industry or their families have filed lawsuits because of injury or death from exposure to diacetyl. Details on the settlements are usually sealed, but it is estimated that the flavoring companies that sold diacetyl-containing butter flavoring have paid more than $145 million in jury awards and last-minute settlements."

Popcorn and butter. So simple, so American -- and now dangerous?

Sloane Miller
Meet Our Writer
Sloane Miller

Sloane Miller, MFA, MSW, LMSW, specialist in food allergy management and author, is founder and President of Allergic Girl Resources, Inc., a consultancy devoted to food allergy awareness. She consults with private clients, the healthcare, food, and hospitality industries, government and not-for-profit advocacy organizations. In 2006, Ms. Miller started Please Don't Pass the Nuts, an award-winning blog for and about people affected by food allergies. In 2011, John Wiley & Sons published Ms. Miller's book, Allergic Girl: Adventures in Living Well With Food Allergies, the definitive how-to guide. Ms. Miller combines a lifetime of personal experience and passion with professional expertise to connect with people about how to live safely, effectively, and joyously with food allergies.