Chemicals in e-cigarette flavors linked to respiratory disease

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Diacetyl, a flavoring chemical linked to cases of severe respiratory disease, was found in more than 75% of flavored electronic cigarettes and refill liquids tested by researchers at Harvard T.H. Chan School of Public Health. Two other potentially harmful related compounds were also found in many of the tested flavors, which included varieties with potential appeal to young people such as Cotton Candy, Fruit Squirts, and Cupcake.

The study will be published online December 8, 2015 in Environmental Health Perspectives.

The Occupational Safety and Health Administration and the flavoring industry have warned workers about diacetyl because of the association between inhaling this chemical and the debilitating respiratory disease bronchiolitis obliterans, colloquially termed "Popcorn Lung" because it first appeared in workers who inhaled artificial butter flavor in microwave popcorn processing facilities.

"Recognition of the hazards associated with inhaling flavoring chemicals started with 'Popcorn Lung' over a decade ago. However, diacetyl and other related flavoring chemicals are used in many other flavors beyond butter-flavored popcorn, including fruit flavors, alcohol flavors, and, we learned in our study, candy flavored e-cigarettes," said lead author Joseph Allen, assistant professor of exposure assessment science.

There are currently more than 7,000 varieties of flavored e-cigarettes and e-juice (liquid containing nicotine that is used in refillable devices) on the market. Although the popularity and use of e-cigarettes continues to increase, there is a lack of data on their potential health effects. E-cigarettes are not currently regulated, but the U.S. Food and Drug Administration (FDA) has issued a proposed rule to include e-cigarettes under its authority to regulate certain tobacco and nicotine-containing products.

Allen and colleagues tested 51 types of flavored e-cigarettes and liquids sold by leading brands for the presence of diacetyl, acetoin, and 2,3-pentanedione, two related flavoring compounds that are listed as "high priority," i.e. they may pose a respiratory hazard in the workplace, by the Flavor and Extract Manufacturers Association. Each e-cigarette was inserted into a sealed chamber attached to a lab-built device that drew air through the e-cigarette for eight seconds at a time with a resting period of 15 or 30 second between each draw. The air stream was then analyzed.

At least one of the three chemicals was detected in 47 of the 51 flavors tested. 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 , respectively.

"Since most of the health concerns about e-cigarettes have focused on nicotine, there is still much we do not know about e-cigarettes. In addition to containing varying levels of the addictive substance nicotine, they also contain other cancer-causing chemicals, such as formaldehyde, and as our study shows, flavoring chemicals that can cause lung damage," said study co-author David Christiani, Elkan Blout Professor of Environmental Genetics.

Explore further

Case report finds 'popcorn lung' in patient using e-cigarettes

More information: "Flavoring Chemicals in E-Cigarettes: Diacetyl, 2,3-Pentanedione, and Acetoin in a Sample of 51 1 Products, Including Fruit-, Candy-, and Cocktail-Flavored E-Cigarettes," Joseph G. Allen, Skye S. Flanigan, Mallory LeBlanc, Jose Vallarino, Piers MacNaughton, James H. Stewart, David C. Christiani, Environmental Health Perspectives, December 8, 2015, DOI: 10.1289/ehp.1510185

This study was supported by NIH/NIEHS Center Grant P30ES000002.

Provided by Harvard University
Citation: Chemicals in e-cigarette flavors linked to respiratory disease (2015, December 8) retrieved 18 October 2019 from
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User comments

Dec 08, 2015
hmm cigarettes basically came in 2 flavors being tobacco or menthol I don't get the flavors for vapes nor do I like them.

Dec 08, 2015
Very strange. So many liquids contain this chemical. Could it be that modern technology is able to detect tiny amounts of a chemical in the liquid? Remember that 'the poison is in the dose'. Every 'chemical' including oxygen and water that are vital to our living are both poisonous in the large enough dose. The existence of a chemical does not make it harmful..... you need to consider the dose.

Dec 08, 2015
Apparently when your dumping 50 pound bags of raw diacetyl into mixing vats there is a potential risk of lung damage as with breathing in any raw pure particulate substance. Dispersed and suspended in a viscous liquid consisting of propylene glycol and or vegetable glycerin it doesn't appear to causing any problems at all.

Dec 08, 2015
"Diacetyl was detected above the laboratory limit of detection."
What is the detectable limit, parts per million, parts per billion?
What level is toxic?
By not giving this information, this article is irrelevant and simply scaremongering.

Dec 09, 2015
I have found that most ecig users are concerned about their health, that's why they don't smoke cigarettes. I have read all the information I could get my hands on regarding the safety of certain chemicals in ejuice flavorings, and found that the risks seem small, much less than regular cigarettes. Diacetyl causes lung disease when workers were being exposed to the powdered form of it in large quantities over many years, and the Diacetyl contained in ejuice is in liquid form in very small quantities.

Vaping is not good for you, but in my opinion it is one of the more healthy options for a nicotine user, or someone who is quitting smoking. People in the industry are constantly trying to make their products safer, and keeping an eye on what goes in them. Compared to the tobacco industry, where additives are added to tobacco regardless of their risks, we are in a much better place with using e-cigs. Now if someone would fund some BIG research on them, we could find out more.

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