A new wave of "heat-not-burn" tobacco products are probably safer than traditional cigarettes but the devices still produce a number of potentially harmful compounds, some of which are carcinogenic, a British panel of experts says.
Cigarette maker Philip Morris International has led the way in developing the new non-burn products and its iQOS device is one of two available in Britain, alongside British American Tobacco's iFUSE.
Whereas e-cigarettes use nicotine-laced liquid, the new devices heat tobacco to a high enough temperature to create a vapour but not smoke.
The Committee of Toxicology (COT), which offers independent scientific advice to the UK government, is one of the first official groups to study the risk profile of heat-not-burn products.
Its report to Public Health England (PHE) said people using such products were exposed to between 50 and 90 per cent fewer harmful and potentially harmful chemicals compared with conventional cigarettes.
But it was unable to quantify the risk precisely versus conventional cigarettes or e-cigarettes because of limited data. The experts also noted significant technical differences between the products, with iQOS generating a maximum temperature of 350 degrees centigrade against 50 degrees for iFUSE.
"The evidence suggests that heat-not-burn products still pose a risk to users," said COT chair Alan Boobis.
"There is likely to be a reduction in risk for cigarette smokers who switch to heat-not-burn products but quitting entirely would be more beneficial."
PHE, which is charged with protecting health and wellbeing, has previously endorsed a shift to vaping with e-cigarettes as a less risky alternative to smoking - but the organisation said the evidence on heat-not-burn was still sketchy.
"Heat-not-burn tobacco products are not the same as e-cigarettes," said Rosanna O'Connor, PHE director of drugs, alcohol and tobacco.
"There is a large amount of evidence that shows vaping is much less harmful than smoking - at least 95 per cent - and we encourage smokers to try e-cigarettes as a way of stopping smoking."
