A new study, published Thursday in Environmental Health Perspectives, adds more evidence to the idea that e-cigarettes aren't an entirely risk-free endeavour. It suggests that the very act of vaping might be exposing people to unsafe levels of toxins like lead and arsenic.
Researchers at John Hopkins University asked 56 daily e-cigarette users — recruited from vaping shops and conventions around Baltimore — to lend them their tank-style devices. These modifiable, reusable devices allow people to refill their supply of e-liquid from a separate bottle dispenser. They first tested the e-liquid in the dispenser for 15 common metals.
Then they tested the aerosol that users inhale into their lungs, which is generated by the e-liquid being heated by a battery-powered metal coil. And finally they tested the remaining liquid left behind in the device.
They found negligible levels of any metal in the dispenser alone. But after the liquid was heated into an aerosol, many of the samples had elevated levels of lead, chromium, nickel, manganese, and zinc. The first three are potentially toxic in most any form, while manganese and zinc are otherwise important minerals that can be dangerous when inhaled. Concentrations of these metals were also elevated, though not as high, in the e-liquid left behind in the device.
The most substantial culprit of this contamination, the researchers found, is almost certainly the metal coil used to heat the e-liquid.
"It's important for the FDA, the e-cigarette companies, and vapers themselves to know that these heating coils, as currently made, seem to be leaking toxic metals — which then get into the aerosols that vapers inhale," said senior author Ana María Rule, an air pollution researcher at John Hopkins' Bloomberg School of Public Health, in a statement.
The research, as alluded to, is only the latest to indicate that e-cigarettes (and the flavored liquids they come packed with) carry their own set of health risks, even if they are less harmful than traditional tobacco cigarettes.
This latest study is in fact the continuation of preliminary research published by the authors last year that studied the same group of users. That study found elevated levels of nickel and chromium in both heated e-liquid as well as in users' urine and saliva.
The looming question, though, is just how much of a health problem vaping actually is. Some of the metals found, like lead, pose a danger no matter how little of them we're exposed to. For other metals, many of the exposure levels found were higher than a safety threshold established by US agencies like the EPA. Puzzling too is the presence of arsenic, since unlike the other toxins they detected, it isn't part of the composition of the coils typically used in e-cigarette devices.
That suggests, the researchers said, that it's being produced by the heating process itself.
The researchers say their findings "suggest that using e-cigarettes instead of conventional cigarettes may result in less exposure to cadmium but not to other hazardous metals found in tobacco."
But other research has continued to find that while e-cigarettes aren't harmless, their overall threat still falls way short of the harms brought on by tobacco cigarettes. Advocates also argue — with mixed evidence — that vaping has helped people quit or cut down on tobacco, representing a net good. Critics have shot back that vaping is enticing a new generation of teens to not only become addicted to nicotine, but possibly even to regular smoking too.
The researchers, for their part, plan to conduct more extensive studies that will hopefully better map out the health risks of vaping. "We've established with this study that there are exposures to these metals, which is the first step, but we need also to determine the actual health effects," Rule said.