According to a study conducted by U.S. scientists, bacterial and fungal toxins linked to lung disease have been found in the cartridges and refill liquids of vaporizers.
The full study was published by Environmental Health Perspectives and can be accessed here.
Past year in the USA, more than three million high school students were believed to have been using e-cigarettes, said the scientists.
I'd add that these new findings should be considered by consumers when deciding to use e-cigarettes, as well.
United States scientists who tested 75 e-cigarette single-use cartridges and refill liquids discovered traces of harmful bug chemicals in 27%.
They found impurities associated with conditions like asthma and chronic obstructive lung disease were present in almost a quarter of all single-use e-cigarette cartridges.
Endotoxin is a potent inflammatory molecule found in bacteria that can seriously damage the lungs.
Boxplots showing the median (horizontal line in box), interquartile range (the central rectangle), and the fifth and the 95th percentiles (whiskers above and below the box) of endotoxin and glucan levels by e-cigarette type and flavor. The products were classified into four different flavor categories: tobacco, menthol, fruit, and other. Of the 75 total products evaluated, 61 contained glucans and 17 contained endotoxin.
Glucan was significantly more abundant in tobacco and menthol-flavoured products, and three times more concentrated in cartridges than in e-liquids.
That's according to an alarming new study from the Harvard School of Public Health.
Products with fruit flavorings were found to have higher endotoxin concentrations. The researchers are quick to note that the contamination of the products could have happened at any point in the production line, or even after the e-cigarette was finished. They hypothesized that cotton wicks used in e-cigarette cartridges may be one potential source of contamination, as both endotoxin and glucan are known contaminants of cotton fibers.
Co-author Dr Mi-Sun Lee, also from the Harvard Chan School, said: "In addition to inhaling harmful chemicals, e-cig users could also be exposed to biological contaminants like endotoxin and glucan".
Publishing their work in Environmental Health Perspectives, Harvard researchers examined 75 popular e-cigarette products that were either single-use cartridges or refillable e-liquids.