Smoke Without Fire? The Truth About Vaping Safety

It’s been a decade since we first wrote a comprehensive post on the safety of vaping.

Back then, vaping didn’t have the support of the UK government, the huge body of evidence and the longer-term studies it now has.

Still, even then we knew that:

·Nicotine is not the cause of smoking diseases.
·Vaping doesn’t produce smoke.
·Vapour from vape devices provided a fraction of the toxins and chemicals found in cigarette smoke.

It led David Sweanor, an expert (and former WHO tobacco control medal award winner) to state:

If there is anyone who believes cigarettes are no more hazardous than e-cigarettes I’d recommend a remedial course in basic sciences.

Ironically, while we now know far more about vaping, the perception of the risk from vaping is far worse than it used to be. While you could write a book about the relative safety of e-cigarettes, this post will outline some of the general reasons why we can have confidence that the UK Government, the Royal Society of Physicians, the NHS, the British Heart Foundation, Cancer Research UK and dozens of organisations are right when they say that vaping is much less harmful than smoking.

What’s wrong with smoking?

The problem with smoking occurs when you burn tobacco. As the smoke cools down, it creates both tar and over 70 toxins which are incredibly bad for you.

In contrast, vaping does not burn anything. Instead, it heats up e-liquid in order to vaporise it. Vape devices vaporise e-liquid using a heat range of around 190°C – 250°C, a temperature comparable to that of an oven – and a far cry from the 900°C a cigarette can reach.

What’s in vapour?


While there is some controversy over nicotine, it’s clear that it is not the cause of smoking-related diseases.

Nicotine increases the heart rate and blood pressure and narrows the blood vessels, much like mild exercise. However, it does not cause cancer or lung disease and plays only a small role in cardiovascular disease.

People have been taking nicotine in the form of Swedish snus for decades – with Dr Joel Nitzkin, chair of the Tobacco Control Task Force for the American Association of Public Health Physicians, telling us that long term use does not increase the chance of death. There is also no evidence that the long-term use of snus causes cancer, lung or heart disease. Perhaps that’s why the Royal Society of Public Health states that nicotine is no more harmful than caffeine.

A side note here – while nicotine is addictive, it’s important to remember that it is not the only addictive element in smoking. What’s more, vaping delivers nicotine more slowly than tobacco cigarettes. That means that vaping is less addictive than smoking, and studies are finding that experimentation with vaping is far less likely to lead to regular use than experimentation with cigarettes.

VG and PG
Vegetable glycerine (VG) and propylene glycol (PG) make up the majority of e-liquid. Both are recognised as GRAS (generally recognized as safe for ingestion). Propylene glycol is widely used, including in inhalers and air conditioners. VG is also widely used in pharmaceutical products, such as cough medicine, as well as in foods.

There have also been animal tests, which involved rats and monkeys inhaling and ingesting high levels of PG for 12 months. The results led researchers to conclude that inhalation for 12 months gave:

“Assurance that air containing these [ecig] vapors in amounts up to the saturation point is completely harmless.”

Looking at this study and others, the UK Committee On Toxicity Of Chemicals In Food, Consumer Products And The Environment (COT) concluded that toxicity associated with exposure to PG is extremely low. They also pointed out that Glycerol (used in vaping in the form of VG) is not considered to be genotoxic or carcinogenic, but with the caveat that there is limited data on the inhalation of glycerol.


Flavourings are another key component in vaping. A key criticism is that flavourings used are food grade, not inhalation grade. There are three errors with this criticism.

First, it’s not correct that all food flavourings are used in vape products. For example, diacetyl, which is used to create a butter texture in popcorn and can be harmful when inhaled in large quantities, is banned in UK e-liquid. A huge amount of toxicology work over the past few years has gone into identifying potentially harmful ingredients, which means more flavourings are being eliminated from e-liquid.

Of course, this does only apply to regulated e-liquids. To maximise the benefit of vaping, it’s important to buy legal products from reputable sellers and responsible manufacturers.

Secondly, as Professor Alan Boobis, chair of the Committee on Toxicity of Chemicals in Foods, Consumer Products and the Environment (COT), pointed out in last year’s E-Cigarette Summit, food ingredients are often heated too, but don’t produce toxins that hurt us. And as we saw earlier, the temperature at which e-liquid is heated is similar to that of an oven.

Finally, in the UK and Europe, both e-liquid and devices have to undergo emissions testing – which means we can now identify e-liquid that can be harmful to us. That reduces the chance we will inhale e-liquid with harmful flavourings.

That said, flavourings are unlikely to be perfect. However, in a regulated environment, risks can be minimised. As our knowledge of vape ingredients grows these residual risks can be further reduced.

Chemicals and toxins
First, let’s deal briefly with chemicals. When people say vapour (or anything else) contains chemicals, it means nothing. Chemicals surround us everywhere. Water is a chemical. Air is made of chemicals. What we need to be concerned with are toxins.

And the news here is good. Evidence shows that most toxins in cigarette smoke are not present in vapour. Public Health England found that carcinogens found in vapour are below that of 1% those found in smoke and unlikely to cause harm to the human body. In fact, Professor Marcus Munafo once commented at the e-cig summit that you are likely to breathe in more toxins from city air than from a vape device.

Remember also that many of the studies conducted on toxins were on older devices and e-liquids. Improvement in technology and toxicology, combined with emissions testing, means there are likely to be fewer toxins in modern devices and we can expect further improvements in the future.


So far we have looked at the ingredients in vaping. Another way to look at relative safety is biomarkers – levels of toxins and carcinogens measured in the blood, saliva and urine.

A number of studies, such as this and this, have found that vapers have far fewer toxins in their bodies than smokers. Reporting at a conference in 2017, Dr Lion Shahab, a Senior Lecturer in Healthy Psychology, University College London, explained that toxicant exposure in vapers was not only much lower than that found in smokers, it was almost identical to those found in non-smokers.

Vaping and the impact on smoking-related diseases
Scientists have also looked at what happens when smokers, including those with smoking-related diseases, switch to vaping. They have found that switching to vaping can:

·reduce blood pressure and improve asthma symptoms
·reduce the risk of heart attack
·lead to recovery in cilia function (which protects against infections)
·reduce the impact of COPD

Vaping and cancer
Smoking carries many risks, but the one that sticks in our minds is cancer – especially lung cancer. One attempt to quantify the risk of cancer from vaping, included in an evidence review by the UK government, estimates the risk to be 0.5% that of smoking, while the lung cancer risk from vaping was estimated in one study to be 50,000 times less than from traditional cigarette smoking.

Improving technology
It’s also important to remember that we are not measuring static technology. While cigarettes are pretty much the same as they were fifty years ago, vaping is a very different beast compared to just 15 years ago.

There have been huge improvements in vaping. Improvements in technology and emissions testing are helping to make the hardware safer. Toxicology work is helping to identify any ingredient that may be of slight concern and eliminate it from e-liquid. Vaping is safer than it was ten years ago, and with the right regulatory environment, it will be safer again in the future.

But what about the long term impact?
One frequent criticism of e-cigarettes is that we don’t know the long term impact of vaping. And it’s true that while we do have some longer term data, those studies have been small in scope.

What we do have is science that tells us vaping is substantially safer than smoking, and studies that show switching from smoking to vaping leads to improvements in health.

Now imagine we took the precautionary approach that we shouldn’t use any intervention that might have some possibility of long term harm, even when the science tells us it will work, and even when it could save 50% of subjects from an early death.

Imagine all the medicines that wouldn’t be created, and all the diseases that wouldn’t be treated. An approach that is overly cautious and ignores the science would stop all progress in public health.


All this does come with a slight caveat. The regulatory environment in the UK and the EU means that (legal) devices and e-liquid are some of the highest quality in the world. Where countries have chosen to ban instead of regulate vaping, black market pressures mean vape products are likely to be less safe. That’s one reason why it is important to regulate, not ban, vaping.

Vapers can also reduce any residual harms by using lower power devices which produce less vapour. Any harm is likely to come from vapour rather than the nicotine, so when you breathe in large amounts of vapour you could be increasing harm.

Why is there so much concern about vaping?
There’s a huge amount of opposition to vaping. The reasons for it are complex, and include everything from threats to tax and funding to the misapplication of the precautionary principle and a determination to denormalise nicotine.

Perhaps because of this, there is a lot of bad science, or science that is misrepresented. A few of many examples are:

·Burning coils and then measuring formaldehyde (even though you can’t vape a burnt coil)
·Pointing out that vapour contains toxins, even when those toxins are lower than those found in air
·Claiming vaping leads to heart attacks and strokes – it turned out the subjects had those heart attacks and strokes before they started vaping
·Blaming a disease caused by Vitamin E Acetate in illegal cannabis on vaping nicotine

As an honorary rodent, I dedicate my life to ending this:

Rats exposed to ecig vapor, at dry wick levels that no human would ever tolerate, in order to "find" harms.

It is very uncomfortable in those tubes.
— Clovis Sangrail (@ClovisSangrail4) March 5, 2021

These claims get a lot of attention in the media. Attempts to explain the problems with these studies, despite the best efforts of the Science Media Centre get little or no attention. Some studies have been retracted – but by the time this happens, the damage has been done.

So is vaping safe?

No, but that’s the wrong question.

Smoking kills one in two long-term users, and vaping nicotine has the potential to displace smoking. So the question really needs to be – is vaping safer than smoking? And the answer is yes, it’s order of magnitudes safer than smoking.

David Sweanor has a talent for getting to the crutch of the matter with a few choice words, so just as I started this post with a quote of his, I’ll leave the last word to him too:

Rather than the unattainable standard of ‘safe’ we should be thinking in terms of ‘safer’…. Despite the risks associated with soccer, I would, for instance, prefer my children play soccer rather than play with live hand grenades.