News Current Events Popular E-Cigarettes Tainted With Toxic Bacteria and Fungus By Melissa Breyer Editorial Director Hunter College F.I.T., State University of New York Cornell University Melissa Breyer is Treehugger’s editorial director. She is a sustainability expert and author whose work has been published by the New York Times and National Geographic, among others. our editorial process Melissa Breyer Updated April 24, 2019 ©. Oleggg Share Twitter Pinterest Email News Environment Business & Policy Science Animals Home & Design Current Events Treehugger Voices If the harmful chemicals weren't bad enough, new research finds that many e-cigarettes also include unhealthy biological contaminants. The good news is that cigarette smoking has declined among American adults, going from 20.9 percent in 2005 to 14 percent in 2017. The not-so-good news is that e-cigarettes are more popular than ever, and especially among teens; it is estimated that more than three million high school students used e-cigarettes in 2018, up from 220,000 in 2011. With their fruity flavors and little puffs of vapor, e-cigarettes may seem innocuous enough, but according to the CDC, inhaled aerosol can contain harmful and potentially harmful substances, including: • Nicotine• Ultrafine particles that can be inhaled deep into the lungs• Flavoring such as diacetyl, a chemical linked to a serious lung disease• Volatile organic compounds• Cancer-causing chemicals• Heavy metals such as nickel, tin, and lead. And now, new research from the Harvard T.H. Chan School of Public Health found some more lovelies to add to the list: Bacterial and fungal toxins. The study looked at 75 popular e-cigarette products, both cartridges (single use) and e-liquids (refillable), and found that 23 percent of them contained traces of endotoxin, a microbial agent found on Gram-negative bacteria. Meanwhile, 81 percent of them contained traces of glucan, which is found in the cell walls of most fungi. Exposure to these toxins can lead to asthma, reduced lung function, and inflammation. "Airborne Gram-negative bacterial endotoxin and fungal-derived glucans have been shown to cause acute and chronic respiratory effects in occupational and environmental settings," said David Christiani, Elkan Blout Professor of Environmental Genetics and senior author of the study. "Finding these toxins in e-cigarette products adds to the growing concerns about the potential for adverse respiratory effects in users." The products tested included 37 e-cigarette cartridges and 38 e-liquid products from the country's 10 most popular brands. Where the contamination occurred was not determined; the researchers said that it could happen at any point, from the production of the ingredients to the finished product. But they found that the endotoxin concentrations were higher in fruit flavored products, suggesting the possibility that raw materials used to create the flavors might be a source of microbial contamination. They also suggested that the cotton wicks used in these products could be a potential source of contamination since both endotoxin and glucan are known contaminants of cotton fibers. "In addition to inhaling harmful chemicals, e-cig users could also be exposed to biological contaminants like endotoxin and glucan," said Mi-Sun Lee, research fellow and lead author of the paper. "These new findings should be considered when developing regulatory policies for e-cigarettes." I'd add that these new findings should be considered by consumers when deciding to use e-cigarettes, as well. The research was published in Environmental Health Perspectives.