In the early days of the vaping industry, some e-cigarette users were alarmed when certain e-liquids, subjected to lab tests, were found to contain diacetyl. Diacetyl is an artificial butter flavor used in products such as microwave popcorn. Inhaling it in large quantities is known to cause the irreversible lung disease bronchiolitis obliterans, or “popcorn lung.” As a result of this scare, e-liquid makers across the world announced that they were going “diacetyl-free,” and the world rejoiced.

Diacetyl E-Liquid Popcorn Lung StudyUnfortunately, it seems that creating diacetyl-free e-liquids isn’t as easy as simply trusting the word of your suppliers. In 2015, Vapor Shark — a vendor of many different e-liquid brands — sent samples of all of its e-liquids to a laboratory for testing. The results were alarming; in fact, up to 69 percent of sweet e-liquids — which most e-cigarette users seem to prefer — still contain diacetyl, even if the maker claims that its products are diacetyl-free.

Some e-liquid companies made changes as a result of this study. Published lab tests are more common than ever and today a great many e-liquid companies now have paperwork to back up the claim that their e-liquids are free of diacetyl. Unfortunately, though, some e-cigarette users have not changed their habits after this new information came to light. Perhaps they were unaware of the facts, or they trusted a vendor that didn’t really know what they were selling — or they simply comforted themselves in the fact that so far, no e-cigarette user had actually contracted popcorn lung.

Yesterday, October 19, the website Medical Xpress published what was thought to be confirmation of the first e-cigarette user with popcorn lung. The study, conducted by a team of hospital researchers in Vermont, details the case of a man who smoked cigars and used an e-cigarette heavily flavored with diacetyl. His symptoms included weakness, chills, cough, fever and hypoxemia. His symptoms improved with treatment, and according to the final study published in CHEST, his lung function was normal after three months without using the e-cigarette.

The final diagnosis? Inhalational injury and acute hypersensitivity pneumonitis, caused by usage of an electronic nicotine delivery system.

Although it is impossible to determine whether the patient’s temporary respiratory issues were in fact caused by the diacetyl in his e-liquid, this study does bring light to the fact that you really ought to know as much as possible about what your e-liquids contain. As I mentioned above, more and more e-liquid makers are subjecting their own products to lab tests and sharing the results with the public. For more information about what some of these companies are doing, take a look at these links from V2 Cigs, VaporFi, Black Note and Halo.

Vapegrl is a freelance writer and eCig One news contributor who switched from cigarettes to e-cigarettes in 2010. Vapegrl launched an e-cigarette website in 2012. is a newbie-friendly e-cigarette information resource for new and experienced e-smokers.