For Health



Flavoring Chemicals in E-Cigarettes

Flavoring Chemicals in E-Cigarettes

There are over 7,000 e-cigarette flavors currently marketed. Flavoring chemicals gained notoriety in the early 2000s when inhalation exposure to the flavoring chemical diacetyl was found to be associated with an inflammatory lung disease known as “Popcorn Lung.”  To date, there has been limited research on flavoring chemicals in e-cigarette liquids. 

The World Health Organization reports that $3 billion was spent on e-cigarettes in 2013 in the United States alone, with sales expected to increase 17-fold over the next 15 years. The Centers for Disease Control estimates that in 2012 and 2013, at least 1.78 million children in the U.S. tried e-cigarettes. E-cigarettes were sold in the U.S. unregulated until May of 2016, when the U.S. Food and Drug Administration issued a rule to extend regulatory authority to all tobacco products, including e-cigarettes, and put age and packaging restrictions into effect. As the popularity and consumption of e-cigarettes continues to increase, the need for data on the exposures and potential human health effects of e-cigarette use is crucial.


The flavoring chemicals studied were diacetyl and two other “high-priority” flavoring chemicals, acetoin and 2,3-pentanedione, which pose health threats such as respiratory hazards in the work place. Fifty-one flavors of e-cigarettes, deemed appealing to youth from leading e-cigarette brands, were selected for testing. E-cigarette contents were fully discharged and the e-cigarette vapor air stream was analyzed for total mass of diacetyl, acetoin and 2,3-pentanedione.


At least one of the three flavoring chemicals were detected in 47 of the 51 unique flavors tested (92%). Diacetyl was detected in 39 of the 51 flavors tested (76%), and acetoin and 2,3-pentanedione were detected in 46 and 23 of the 51 flavors tested, respectively (90% and 45%). The presence of these chemicals in e-cigarette vapor and the associations between diacetyl, bronchiolitis obliterans, and other severe respiratory diseases observed in workers necessitates urgent action to further evaluate this potentially widespread exposure from flavored e-cigarettes.

View the Report

In the Press:
Chemicals linked with severe respiratory disease found in common e-cigarette flavors