“Smokers warned over e-cigarette cancer risk as study discovers deadly paint-stripper toxin”

Wow, that sounds really bad, you would have to admit! Any person reading this headline would be justified in pausing for thought to ask themselves some serious questions. What is this deadly cancer causing chemical and how much is in my e-cig? Maybe I should go back to cigarettes?  Let’s clear each one of those questions up right now. The chemical is called benzene (not deadly paint stripper toxin!), you’ll probably breathe more when you walk down the street and you’re very likely to get cancer in later life if you continue to smoke.

Fake News

So is this another case of Donald Trump style fake news in the e-cigarette public health debate? Before being accused of sounding like the new Trump administration shall we agree ‘misleading’ is the best way to describe such news? Indeed seasoned vapers have long experience of misleading headlines and downright bad science but this cannot be said for the average member of the public who might be trying to quit the fags using e-cigarettes. Make no mistake this headline will have prevented smokers in the UK from making a life changing decision to quit a habit that will kill one in two of them. We can’t even completely blame the UK tabloid press for misleading the public as the broadsheet newspapers are also guilty of headline after headline on the dangers of e-cigarettes.

Science editors at newspapers don’t tend to look into e-cigarette research papers in much detail; if they did it might open their eyes to the truth. No, they rely on the research paper press statements for their sensationalised headline and article content. This is where the real problem lies and exposes a worrying trend in e-cigarette research where the press statement doesn’t accurately reflect the results of the study. We can use the “deadly paint stripper toxin” story to illustrate this trend and also query the desire of some scientists engaged in e-cigarette research to solve problems that don’t really exist.

Scientific News

In academia, the majority of scientific publications go under the radar and are not considered of sufficient importance to warrant the university press office to release a statement. If the research is high profile and a significant breakthrough has been made then a press statement will accompany the journal publication. This factual statement describes the background to the work, standout results and is often accompanied by a quote from the lead researcher outlining the significance of the achievement. In the case of e-cigarette research, academic press statements (especially from the USA) tend to sensationalise the work in a manner rarely witnessed in any other field. In this specific example, the press statement headline tells us of cancer-causing benzene found in e-cigarette vapours operated at high power. The statement goes further to inform the public that benzene levels were thousands of times higher than ambient air with the caveat that the levels were still 50 to 100 times lower than conventional cigarettes. So the press have been informed that e-cigarettes operating at high power produce high levels of benzene. Journalists take this information and write stories for many newspapers so the message of the deadly benzene find is communicated globally. But let’s take a look at the actual detail of the paper to ascertain what the researchers have really discovered.

The Study in Detail

The study focused on three e-cig kits, the JUUL cigalike prefill pod device and two variable wattage devices. The JUUL cigalike contains an unusually high concentration of nicotine (6%, TPD non-complaint) and the additive benzoic acid. The hypothesis was that nicotine could act as a catalyst for the decarboxylation (fancy chemistry term for loss of carbon dioxide) of the benzoic acid to form benzene. None was detected. As the JUUL is not a variable wattage device it wasn’t possible to raise the wattage high enough to measure any benzene so they decided to move onto the two variable wattage devices.

Benzene in e-cigs study findings


The researchers understood that the key to finding any benzene in the vapour was higher power with the addition of chemicals; benzoic acid and benzaldehyde (sounds like trying to force a result, doesn’t it?). Benzaldehyde is a flavour additive in a minor number of e-liquids such as cherry flavour.  The researchers reported that in commercial e-liquid they found 0.02- 2 mg/mL of benzoic acid but then decided to ignore that data and add 9 mg/mL to their VW device test e-liquids with the addition of 10 mg/mL of benzaldehyde. Did they realise that even at the upper limit of 2 mg/mL benzoic acid and higher power (dry puff conditions) no benzene formation would be observed? When the VW devices were operated at recommended power settings they found no benzene in the majority of samples and conditions. When the VW devices were pushed to dry puff conditions (and 5 second puff duration!) with a combination of additives the researchers found the minor benzene emissions they had been searching for in a handful of samples.

The authors then calculated the concentration of benzene in inhaled air at levels of up to 5000 μg/m3 and compared it to ambient levels of 1 μg/m3.  Ignoring the fact that the highest result was obtained under unrealistic dry puff conditions (and with specific chemical additives) the press release focused on this calculation and the thousands of times higher than ambient tagline was born! However, there is one problem with the calculation that the researchers made and the subsequent press release. The analogy only works if we breathe once a day! The daily exposure to benzene from ambient air is estimated at 20 μg. If we work back through the data it becomes clear that even at high wattage device specific (unrealistic) conditions a vaper would need to consume over 100 mL of e-liquid per day in order to be exposed to the same levels of benzene as breathing air! But that doesn’t have the same eye catching potential for the press release, I think we can all agree.

The So What?

So what have we learnt from this exercise? In the rapidly expanding field of e-cigarette research it seems the academic institutions that shout the loudest get paid the most attention by the media. Sensationalised press releases regarding the hidden dangers of e-cigarettes often suffer glaring inconsistencies with the actual study findings. But a press statement saying “e-cigarettes do not form benzene” doesn’t have quite the same appeal to newspaper science editors as “cancer causing benzene found at levels thousands of times higher than air”.