New Chemical Found in E-liquid: Is Diacetyl Safe For Vapers?


A new study published on 8/12/15 in Environmental Health Perspectives, found diacetyl in more than 75% of e-liquids tested by researchers at Harvard T.H. Chan School of Public Health.

What is diacetyl and is it safe to be vaped?

Diacetyl is a flavoring chemical used by many e-liquid manufactures in sweet e-liquids such as candy, fruit, and cake flavors. This chemical is generally used in microwave popcorn to achieve the sweet buttered flavor.

Workers in several factories manufacturing artificial butter flavoring were diagnosed with bronchiolitis obliterans, a severe pulmonary disease popularly known as “popcorn worker’s lung”, because it was first seen in a former worker from a microwave popcorn factory in USA.  The United States National Institute for Occupational Safety and Health has consequently suggested diacetyl may be hazardous when heated and inhaled over a long period.

The cases of this respiratory disease have been found in young, healthy, nonsmoking males.

“Although I agree that we should know if e-liquids contain diacetyl and acetyl propionyl, I must note that the study has missed some very important points. One is the assessment of the levels found in their samples”, states Dr Farsalinos, Cardiologist and e-cigarette researcher.

According to Farsalinos, the levels of diacetyl are “absolutely minimal, and it is not expected to raise any concerns about human health effects.” In addition, Fasalinos points out on his blog that the authors of this research; “failed to mention the presence of these compounds in tobacco cigarette smoke.”

Diacetyl was detected above the laboratory limit of detection in 39 of the flavors tested. Acetoin and 2,3-pentanedione were detected in 46 and 23 and of the flavors, respectively.

This worrying topic for e-cig users is not completely new. A 2014 publication found that diacetyl was present in samples of many sweet-flavoured electronic cigarette liquids, though at levels 100 times lower than that of tobacco smoke. The study concluded that diacetyl is “an avoidable risk for electronic cigarette liquid, and measures could be taken by the industry to eliminate its usage, without limiting availability of flavors.”



Ryan is a vaper, editor and content creator who spends most of his time bringing the interesting, entertaining, original and well-written articles to vapers. He believes that vaping is not only a healthier alternative to smoking, but also a great experience of life.