Answer: Microwave popcorn has been around for more than 50 years, since the invention of microwave ovens. Microwave popcorn is relatively easy to make at home using popcorn, a brown bag, some staples (yes, staples!) and other ingredients, such as salt and butter. More commonly, people make popcorn in their microwave using ready-made microwave popcorn packages, many of which contain additional chemical ingredients. The chemicals that are used to give microwave popcorn its buttery flavor are the reason why microwave popcorn has been in the news recently. In particular, scientific studies have linked diacetyl and other chemicals that give the popcorn its buttery flavor to lung damage in people that work in microwave popcorn factories. A study by the National Institute for Occupational Safety and Health (NIOSH), for example, showed that microwave popcorn workers were continually exposed to high levels of these buttery chemicals and that these high levels were related to a serious and permanent type of lung disease, often called "popcorn lung". These risks were shown in workers exposed every now and then to very high levels of butter-flavoring chemicals and also in workers continually exposed to lower (but still higher than normal) chemical levels. Similar findings have also been shown in other scientific studies of people and animals, providing important, supporting evidence that inhaling large amounts of butter-flavoring chemicals is dangerous to your health. These dangers to workers are well-accepted, as evidenced by the fact that just this week, the the US House of Representatives passed H.R. 2693, the Popcorn Workers Lung Disease Prevention Act.
Whether there are similar risks for the general microwave popcorn-eating public, has not been studied, but any potential risks should be limited to those eating popcorn with artificial butter flavoring. Even for these people, risks are thought to be low, since people preparing pre-packaged microwave popcorn at home are exposed to lower chemical levels and for much shorter time periods than the workers. Recently, however, health concerns were raised for people who eat a lot of pre-packaged microwave popcorn. In July 2007, a pulmonary doctor from Denver's National Jewish Medical and Research Center notified the U.S. Food and Drug Administration (FDA) of a patient who ate butter-flavored microwave popcorn several times a day for years and who now has a disease similar to "popcorn lung". As a result of this letter, FDA, the U.S. Centers for Disease Control (CDC), and the U.S. Environmental Protection Agency (EPA) are looking into the possible dangers of preparing pre-packaged microwave popcorn at home. Regardless of what they find, many makers of pre-packaged microwave popcorn have plans to stop adding diacetyl to their popcorn.
Until this time, there are several things that you can do to reduce any risks and/or your worry over pre-packaged microwave popcorn. Clearly, the most foolproof solution is to make microwave popcorn that does not contain artificial butter or to stick to homemade microwave or stove top popcorn. If you do prepare butter-flavored microwave popcorn, you can limit your exposures to the buttery chemicals by venting your microwave oven to the outside, opening nearby windows when you microwave the popcorn, letting the popcorn cool before you open the bag, and opening the popcorn bag outside.
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Helen Suh MacIntosh is a professor in environmental health at Harvard University and studies how pollution behaves in the environment and how it affects people's health. Please keep in mind that her answers are just her interpretation of available information
and should not be taken as the only viewpoint or solution to a problem. Use this column at your own risk. Having said this, please feel free to post any of your environmental health questions to Helen@TreeHugger.com. (Please use a descriptive email subject line and mention if you want to remain anonymous or not).