According to some studies, microwave popcorn manufacturers coat the disposable bag with a chemical that breaks down during the microwaving process, creating a substance known as perfluorooctanoic, or PFOA. The Environmental Protection Agency classifies PFOA as a carcinogenic substance, and it has been associated with an increased risk of liver and prostate cancer. In 1993, Dr. Frank Gilliland wrote an article in the “Journal of Occupational Medicine” which claimed that workers exposed to the compound had an increased risk of cancer.