Flavoured e-cigarettes produce 'unacceptably dangerous' levels of cancer-causing toxins, study finds

Smoking flavoured e-cigarettes can produce “unacceptably dangerous” levels of formaldehyde and other carcinogenic compounds, according to a new study.

Researchers at the Desert Research Institute in Nevada found that toxic aldehydes formed when the flavoured liquid was rapidly heated to create vapour.

E-cigarettes are currently sold in thousands of different flavours, with some sweet varieties thought to be particularly appealing to children.

One of the scientists, Professor Andrey Khylstov, said: “How these flavouring compounds in e-cigarette liquids affect the chemical composition and toxicity of the vapour that e-cigarettes produce is practically unknown.

“Our results show that production of toxic aldehydes is exponentially dependent on the concentration of flavouring compounds.”

The scientists tested five different flavours and three kinds of e-cigarette, a cartomizer and two types of clearomizers, they reported in the journal Environmental Science & Technology.

“One puff of any of the flavoured e-liquids that we tested exposes the smoker to unacceptably dangerous levels of these aldehydes, most of which originates from thermal decomposition of the flavouring compounds,” said Professor Khylstov.

“These results demonstrate the need for further, thorough investigations of the effects of flavouring additives on the formation of aldehydes and other toxic compounds in e-cigarette vapours.”

The researchers tested different concentrations of flavoured and unflavoured e-cigarette liquids.

In all the experiments, the flavoured e-cigarettes produced higher levels of aldehydes than the limit for hazardous chemical exposure set by the American Conference of Governmental Industrial Hygienists. The higher the level of flavour, the larger amounts of aldehydes were produced.

Professor Vera Samburova, who also took part in the study, said: “To determine the specific role of the flavouring compounds we fixed all important parameters that could affect aldehyde production and varied only the type and concentration of flavours.”

A review by Public Health England earlier this year found that e-cigarettes were 95 per cent less harmful than tobacco, suggesting they could be prescribed to smokers to help them quit.

But some experts have suggested this idea could be premature.

In August, Professor Charalambos Viachopoulos, of Athens University, warned that while e-cigarettes are “less harmful than traditional cigarettes … they are not harmless”.

“There could be long term heart dangers. They are far more dangerous than people realise.”