At a public workshop event put on by the U.S. Food and Drug Administration (FDA) in March of 2015 regarding electronic cigarettes and the public health, diacetyl was the center for discussion for its use in e-cigarettes, and its potential toxicity to the lungs when inhaled.
Diacetyl and 2,3 pentanedione (a diacetyl substitute) are chemicals that produce a buttery or creamy flavoring. It is found in microwave popcorn, flavored coffee, ready-to-mix desserts, oil sprays, and many more processed products. It is also a common chemical used in flavorings of e-cigarettes.
The potential danger of diacetyl is alarming: when inhaled, the person becomes at risk for developing obliterative bronchiolitis, a serious lung disease that is also known as “popcorn lung” for the microwave popcorn plant workers that developed the lung disease in 2000. Obliterative bronchiolitis is a disease where the smallest airways of the lungs become scarred and restricted. The symptoms include difficulty breathing, and are very similar to the symptoms of COPD. This is a lung disease that is only treatable by lung transplant.
According to the FDA workshop, 159 e-cigarette flavorings were tested for the chemical, and it was found in 74.2 percent of the flavorings. Diacetyl in an e-cigarette may pose an elevated risk of hazardous exposure because the chemical is heated before inhaled. The Flavor Extract Manufacturer’s Association (FEMA) said, “Heating will increase volatility and greatly increase air concentrations of flavoring substances.”
Some arguments side with the idea that diacetyl is considered perfectly safe to ingest. But Dr. Ann Hubbs, a speaker at the event with the National Institute for Occupational Safety and Health at the U.S. Centers for Disease Control and Prevention (CDC), said, “safe enough to eat does not mean you can breathe it.”
The FDA hosted a second workshop on the topic in June 2015, as the debate surrounding e-cigarette safety continues.