Lauren Poole of House of Vapes, uses a vape in London, Britain August 17, 2018.
The report also found that second-hand vapour wasn't as risky as previously thought, and that e-cigarettes aren't a gateway to smoking.
Vaping on an e-cigarette is much less harmful than smoking regular cigarettes, according to MPs, who say the rules around using them should be relaxed. They accused the MPs of largely taking evidence from researchers who had published studies positive to e-cigarettes and of ignoring evidence highlighting health risks.
A study here this week, for example, found that e-cigarette vapour may cause adverse changes in lung cells.
The committee also recommended that the government and Medicines and Healthcare products Regulatory Agency should, with the e-cigarette industry, look at how the approval systems for stop smoking therapies could be "streamlined" should manufacturers put forward a product for medical licensing.
"E-cigarettes are less harmful than conventional cigarettes, but current policy and regulations do not sufficiently reflect this and businesses, transport providers and public places should stop viewing conventional and e-cigarettes as one and the same".
Spokeswoman Moira Gilchrist said: "We strongly support the recommendation for the relaxation of regulations that would allow smokers to be informed about the health benefits of alternatives to smoking such as e-cigarettes". "If used correctly, e-cigarettes could be a key weapon in the NHS's (National Health Service) stop smoking arsenal".
Speaking on Tuesday, Hazel said: "This study provides some insights into what the implications could be of long-term use of e-cigarettes". Juul said it chose Britain as its third market - after the USA and Israel - partly because of the country's supportive approach to vaping.
It is estimated that about 470,000 people are using them as an aid to stop smoking and tens of thousands are successfully quitting smoking each year as a result.
George Butterworth, from Cancer Research UK, said: "The evidence so far shows that e-cigarettes are far less harmful than tobacco".
'There is no public health rationale for doing so.
"Medically licensed e-cigarettes would make it easier for doctors to discuss and recommend them as a stop smoking tool to aid those quitting smoking".
- So they could be more harmful than has been said?
The Government has said it will "carefully consider" the evidence and recommendations made by the STC.
The University of Birmingham has done research which found the vapourised e-liquid fluid in e-cigarettes has a similar effect on the lungs and body that is seen in regular cigarette smokers and patients with chronic lung disease.
"However, we recognise that the evidence surrounding the use of e-cigarettes is evolving, and there are over three million vapers in the United Kingdom already".
Duncan Selbie, chief executive of PHE, said: 'E-cigarettes are not without harm but are way safer than the harms of tobacco.
"We want to see a tobacco-free generation within 10 years and this is within sight".