How Technology Turned a Healthy Snack Harmful

Microwave popcorn has seemed like a relatively harmless snack, but lately there have been some news reports that question whether that’s really so. The scariest one links microwave popcorn to an illness called bronchiolitis obliterans, a potentially fatal lung disease. Several workers in popcorn factories have died from it while others were in need of lung transplants. That’s bad enough, and in fact, there have been lawsuits filed for hundreds of factory workers — but last year, the problem reached consumers, too, when the condition (also called “popcorn lung”) was diagnosed in a 53-year-old consumer who’d eaten several bags of popcorn a day for years.


Animal studies have shown that inhaling vapors produced in the manufacturing process for microwave popcorn, in particular those from the butter flavoring, is damaging to the airways, I learned from David Michaels, PhD, MPH, a research professor and associate chairman of the department of environmental and occupational health at The George Washington University School of Public Health and Health Services. Dr. Michaels has been studying the issue for four years and has led the pack in bringing attention to the dangers. He explained that a harmful chemical called diacetyl (2,3-butanedione) is released when the artificial butter flavoring is heated. Interestingly, diacetyl also is released when heating real butter, but in far lower, nontoxic amounts. The same holds true for popcorn with artificial butter flavoring prepared other ways, too.


If you’re thinking the solution is to develop a taste for the unbuttered version of microwave popcorn, think again. The other news report I’d heard was about the bags in which the popcorn is cooked. The grease-resistant coating inside the bags is manufactured with fluorinated chemicals called telomers that, when heated, break down into C8, which is considered a possible carcinogen. This is the chemical used in nonstick cookware and a study done in part by an FDA researcher found that levels of chemical concentrations from popcorn bags were sometimes much higher than in the cookware. The Ohio Department of Health’s Bureau of Environmental Health also says these chemicals can be found in fast food containers such as French fry boxes.


Some of the nation’s biggest producers of microwave popcorn (ConAgra Foods, General Mills, American Pop Corn Company and Weaver Popcorn Company) have already changed their recipes and removed diacetyl from their microwave popcorn formulas. Dr. Michaels urges caution nonetheless: “They are replacing diacetyl with other chemicals that have not been adequately tested,” he warned. Additionally, removing the diacetyl does not address the risks of the fumes from the bag’s grease-resistant coating. Dr. Michaels advises sticking with popcorn that has no artificial flavors.

“Air popped popcorn remains perfectly safe for consumers,” he told me. Miss the butter flavor? Try putting a little bit of real butter on the popcorn once it’s popped.