Researchers have warned that people who vape may still be at risk of developing cancer.
The smoking alternative - which is not as harmful as tobacco - may still be harmful and medical experts admit that its dangers are still not fully known.
As many as 3.6 million people in the UK vape, and it is a popular substitute for people who are trying to quit smoking.
The potential warning has been raised by the Francis Crick Institute (FCI), a biomedical research centre in London, reports Wales Online.
They wanted to find out what caused lung cancer in the around one in eight patients who do not smoke in the UK, as smoking is a leading cause of the disease.
Professor Charles Swanton, clinical scientist at the FCI and chief clinician at Cancer Research UK, told The Independent : "I don’t think we can say vaping is necessarily a safe option to quit smoking."
The professor says that it may be safer but that doesn’t make vaping safe. Professor Swanton added: "We don’t know for certain that vaping won’t cause lung cancer 10 years from now."
The researchers used studies on humans and mice which measured exposure to sooty pollution particles in the air that can cause cancerous cells to grow in the lungs.
Their findings indicate that the pathway that causes tumours in non-smokers differs from those caused by smoking, which is thought to prompt a direct mutation to DNA that can lead to cancer.
The results suggest that irritants such as air pollution bring about inflammation that precedes a healing process that "wakes up" dormant cells capable of triggering cancerous mutations. Scientists are concerned that vaping might cause the same process.
Researchers think anti-inflammatory drugs could go some way towards halting the process that causes cancer. But they warn this could be years away.
Don't miss the latest news from around Scotland and beyond - Sign up to our daily newsletter here.
