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Harvard study raises concern about contaminated e-cigarettes

Are there harmful substances in e-cigarettes? stock.adobe.com

That e-cigarette you’re puffing on could be contaminated, according to a newly released study from the Harvard T.H. Chan School of Public Health.

The study, entitled “Endotoxin and (1®3)-b-D-glucan Contamination in Electronic Cigarette Products Sold in the US,” was published Wednesday in Environmental Health Perspectives.

The study “examined 75 popular e-cigarette products — cartridges (single use) and e-liquids (refillable material) — [and] found that 27 percent contained traces of endotoxin, a microbial agent found on Gram-negative bacteria, and that 81 percent contained traces of glucan, which is found in the cell walls of most fungi,” the Chan School said in a statement. The school said exposure “to these microbial toxins has been associated with myriad health problems in humans, including asthma, reduced lung function, and inflammation.”


David Christiani, the Elkan Blout Professor of Environmental Genetics at the Chan school and senior author of the study, said in the statement that the findings are concerning.

“Airborne Gram-negative bacterial endotoxin and fungal-derived glucans have been shown to cause acute and chronic respiratory effects in occupational and environmental settings,” Christiani said. “Finding these toxins in e-cigarette products adds to the growing concerns about the potential for adverse respiratory effects in users.”

His comments were echoed by Mi-Sun Lee, a Chan school research fellow and lead author of the paper.

“In addition to inhaling harmful chemicals, e-cig users could also be exposed to biological contaminants like endotoxin and glucan,” Lee said in the statement. “These new findings should be considered when developing regulatory policies for e-cigarettes.”

But the American Vaping Association, an advocacy group for the industry, on Wednesday took issue with the study’s grim findings.

“This data is based on ancient products that were in use six years ago, meaning that modern devices like JUUL were not studied,” the association said in a statement. “Bacteria and other toxins are found in traditional cigarettes, almost assuredly at much higher levels than found in this study. With many adult smokers now mistakenly believing that vaping could be as dangerous as smoking cigarettes, it is disgraceful to release this study without an adequate comparison to cigarettes.”


The group said nothing “in this study is likely to change the conclusions of respected organizations such as the Public Health England and the Royal College of Physicians, both of which have estimated vaping to be at least 95 percent safer than smoking cigarettes.”

The Harvard team sees it differently. According to the Chan school, its prior research has shown “that chemicals linked with severe respiratory disease are found in common e-cigarette flavors. Moreover, research by investigators conducted over many decades has shown chronic lung impairment in populations exposed to airborne biological contaminants. Yet, according to the authors, no research exists on the potential contamination of e-cigarettes with microbes or microbial toxins.”

For the study published Wednesday, the Chan school said, “researchers selected 37 e-cigarette cartridges, sometimes referred to as ‘cigalikes,’ and 38 e-liquid products, which can be used to refill certain cartridges, from the 10 top-selling US brands. The products were classified into four different flavor categories: tobacco, menthol, fruit, and other. All of the products were then screened for the presence of endotoxin and glucan.”

The findings, according to the Chan school, “showed that 17 of 75 products (23 percent) contained detectable concentrations of endotoxin and that 61 of 75 products (81 percent) contained detectable concentrations of glucan.”


The statement continued, “Further analysis showed that cartridge samples had 3.2 times higher concentrations of glucan than the e-liquid samples. Glucan concentrations were also significantly higher in tobacco- and menthol-flavored products than in fruit-flavored products. The study also found that endotoxin concentrations were higher in fruit-flavored products, indicating that raw materials used in the production of flavors might be a source of microbial contamination.”

Travis Andersen can be reached at travis.andersen@globe.com. Follow him on Twitter @TAGlobe.