Much ado about nothing

Harvard’s diacetyl scare – Fergus Mason

Yet again there’s a new study out on vaping, and as usual it’s stuffed full of scary words like diacetyl. However a closer look suggests that the researchers have found little that’s new and nothing that’s scary.

So diacetyl is back in the news again, with a new paper from a group of researchers at Harvard University. This one claims that the flavouring is found in 75% of all e-liquids, not just the creamy flavours it’s usually associated with. Predictably the usual suspects in the media are all over it; the Telegraph’s abysmal “science editor” Sarah Knapton simply took Harvard’s press release and moved a few words around. Jasper Hamill, her equally inept counterpart at the Mirror, gave it a more extensive rewrite but managed to preserve all its alarmist claims. Nobody bothered to look any deeper at what the study had actually found, least of all the university’s own Harvard Gazette. This appalling rag initially released the story under the title “Popcorn lung seen in e-cigarette smokers”. Hours later they backed down when asked to come up with a case, and changed it to the marginally less hysterical “Chemical flavorings found in e-cigarettes linked to lung disease”. In dim light that’s actually close to accurate, so let’s look at the study itself.

The researchers bought 51 different flavours of e-liquid and prefilled cartomizers from a variety of vendors, then tested them all for diacetyl and the related flavourings acetoin and 2,3-pentanedione (AP). In 47 of them they found at least one of the chemicals – diacetyl was present in 39 cases. Pretty worrying, right?

Slow down. Diacetyl is a worry, and it would be better if liquid manufacturers stopped using it, but we do need to look at how much was actually there. Harvard’s press release only said the chemicals were detected “above the limit of detection”, which for a top university is stunningly stupid. What happens below the limit of detection? That’s right; it’s not detected. So saying it was found above the limit of detection doesn’t actually mean very much; they could be talking about absolutely minute traces here. And often they were.

So here’s something interesting. Before an experiment begins the test equipment has to be validated, to make sure it’s working properly. The Harvard team tested theirs seven times without an e-cig installed, just sucking in clean air, and analysed the filters as normal (new filters were used for each test). On four of those seven test runs diacetyl, acetoin or AP was detected – and the diacetyl level was higher than in 13 of the e-cigarettes! That’s so amazing that I need to say it again; a third of the “dangerous” diacetyl-containing e-cigs contained less diacetyl than a sample of fresh air.

No doubt some people would argue that there’s no safe level of a toxic substance, but if anyone ever says that they’re either completely clueless about toxicology or they’re lying. There is nothing that there isn’t a safe level of. Arsenic, hydrogen cyanide, taipan venom, even the dreaded second-hand smoke – they all have a level below which they’re safe. So how safe is diacetyl in the quantities this experiment found? It’s not easy to convert the micrograms measured by the researchers with the parts per million safe limits are calculated in, but we can compare it with something else that contains diacetyl and is inhaled. Let’s take cigarette smoke.

Smokers die of many things, but popcorn lung doesn’t seem to be one of them. So far, no case of popcorn lung has ever been linked to smoking. Under its correct name of bronchiolitis obliterans the disease has been linked to many other things, from working in textile mills to burning trash pits at military bases in Iraq, but not to smoking. Ever. And cigarette smoke contains a lot more diacetyl than any e-cig vapour does. In Dr Farsalinos’s experiments last year he found that levels in vapour were ten to one hundred times lower than in smoke; the Harvard team found they were from twenty to sixteen thousand times lower.

Yes, it would be better if there was no diacetyl – or acetoin, or AP – in any e-cigarette vapour. Yes, the industry needs to sort this out quickly before over-zealous regulators do it for them. But does this research show up a new and unsuspected danger that’s going to melt all our lungs? No. Not even slightly.

Originally Published: 10th Dec 2015 by Fergus Mason ECig Plaza. Reproduced here with grateful thanks to David Newell @dnglos and Web Archives