Significance Electronic cigarettes, also known as e-cigarettes, are devices designed to imitate regular cigarettes and deliver nicotine via inhalation without combusting tobacco. They are purported to deliver nicotine without other toxicants and to be safer alternative to regular cigarettes. However, little toxicity testing has been performed to evaluate the chemical nature of vapor generated from e-cigarettes. The aim of this study was to screen e-cigarette vapors for content of four groups of potentially toxic and carcinogenic compounds: carbonyls, volatile organic compounds, nitrosamines, and heavy metals. Materials and methods Vapors were generated from 12 brands of e-cigarettes and the reference product, the medicinal nicotine inhaler, in controlled conditions using a modified smoking machine. The selected toxic compounds were extracted from vapors into a solid or liquid phase and analyzed with chromatographic and spectroscopy methods. Results We found that the e-cigarette vapors contained some toxic substances. The levels of the toxicants were 9 to 450 times lower than in cigarette smoke and were, in many cases, comparable to trace amounts found in the reference product. Conclusions Our findings are consistent with the idea that substituting tobacco cigarettes with electronic cigarettes may substantially reduce exposure to selected tobacco-specific toxicants. E-cigarettes as a harm reduction strategy among smokers unwilling to quit warrants further study.

Vapors from EC contain toxic and carcinogenic carbonyl compounds. Both solvent and battery output voltage significantly affect levels of carbonyl compounds in EC vapors. High-voltage EC may expose users to high levels of carbonyl compounds.

Using an e-cigarette in indoor environments may involuntarily expose nonusers to nicotine but not to toxic tobacco-specific combustion products. More research is needed to evaluate health consequences of secondhand exposure to nicotine, especially among vulnerable populations, including children, pregnant women, and people with cardiovascular conditions.