An article published on 27 November 2014 stated that Japanese research had found that e-cigarettes contain 10 times more carcinogens than tobacco cigarettes. While the study conducted by Dr Kunugita, Director of the Japanese Department of Environmental Health, did claim to have found such high levels of one carcinogen (formaldehyde) in the vapour from one brand of electronic cigarette, we would like to clarify that this result was not included in the published research. In fact, the Japanese study supports existing evidence that e-cigarettes are much less dangerous than tobacco products.

http://www.dailymail.co.uk/health/article-2851665/High-levels-toxin-e-cigarettes-cigarettes.html