Bad Science and Benzene
Another vaping study funded by the US government was released last week, and once again the results have proven to be misleading at best. Fortunately, it's already been debunked.
According to "Benzene formation in electronic cigarettes" scientists were able to detect levels of benzene, a cancer-causing compound also present in gasoline and other petrochemicals, at levels up to 50 times the accepted safe exposure level.
The study does note that traditional cigarettes expose users to 2000 times the benzene exposure limit, but that's where the valuable data seems to end.
Almost immediately after it was released, the study faced a rebuttal from Dr. Konstantinos Farsalinos, a scientist who has spent years researching vaping and was one of the first to call out the critical flaws in methodology used by Food and Drug Administration-backed research.
To start, Farsalinos notes, the study's authors examined the liquid in a JUUL disposable cartridge.
The JUUL, as we noted in an earlier review, is a compact, low-power device with an exceptionally high nicotine level to make up for the relatively low vapor production and anticipated infrequent use. The JUUL did have a high level of benzoic acid (45 mg/ml), related to the high nicotine strength (60 mg/ml). If heated enough, benzoic acid can be converted into the toxic benzene. But that didn't happen with the JUUL, even with a machine pulling on the device for five full seconds, the longest duration the device allows. Farsalinos correctly notes that a five second draw on a high-nicotine device designed for mouth-to-lung vaping, even though it produced no detectable benzene, was still highly unlikely.
Even with the high levels of benzoic acid, the JUUL would have to be heated to its melting point to produce benzene, at which point plenty of other chemicals from the burnt plastic would have likely caused even greater concern from whoever was attempting to vape such a device. Researchers then went looking for benzene in old-school (Kanger Evod, 1.8 ohm coil) and mid-school (Kanger Subtank, 1.2 ohm coil) clearomizers. Using commercially available e-liquid, which had benzoic acid levels of between 0.02 and 2 mg/ml. Again, nothing, even though they heated the Evod to 13 watts and the Subtank to 25 watts – both well above the power level a mouth-to-lung vaper would be able to withstand for a five second draw.
Needing to prove their point, researchers then mixed up their own e-liquid with 9 mg/ml of benzoic acid, below the level in the JUUL but more than four times the level of the most potent e-liquid they could find that was designed for refillable tank systems.
At 6 watts on the Evod (a likely power setting for an actual human user) and 12 watts on the Subtank (same), nothing. At 25 watts on the Subtank, trace amounts of benzene were detected – again remember this is at a setting higher than one would likely ever use a 1.2 ohm coil. Finally, using 13 watts and their specially-concocted high-benzoic acid liquid, researchers got a bingo on the Evod, albeit using a power level that was almost certainly delivering a dry hit that only a machine would be able to stomach. Based on that single finding, the study authors warn that "For non-smokers, chronically repeated exposFor non-smokers, chronically repeated exposure to benzene from e-cigarettes at levels such as 100 or higher μg/m3 will not be of negligible risk to benzene from e-cigarettes at levels such as 100 or higher μg/m3 will not be of negligible risk," warning that higher-powered devices (presumably when paired with low-power toppers and creating intentional dry hit conditions as the study did) could result in higher levels of exposure.
Dr. Farsalinos, however, sums up their findings as such:
"The press statement mentions that: 'The power levels used in the study were still far below those accessible to users on some devices, which can exceed 200 watts'. This statement is similar to saying that: 'We crashed with a car in Trafalgar Square with a speed of 100 mph, but still that was far below the 150 mph speed that cars can reach'.
Another similar statement would be: 'Eating 5 kg of vegetables in one meal can lead to death, but that is still below the tens of kg available in grocery store where customers buy their vegetables'.
"I understand it is frustrating to desperately try to find a problem but fail. And this is not the first time, we’ve seen it in the past (and recently) with formaldehyde and other toxic aldehydes (just wait for a couple of papers that will be published soon). However, this still does not prevent the mis-presentation of evidence and science. Also, scientists completely ignore the dry puff phenomenon and instead of them verifying realistic conditions in their experiments, they consider theoretical the criticism they get for their own omission!"