Bad news, vapers. Your e-cigs might not be the healthier alternative to cigarettes you think they are.

A new study has found that vaping may be exposing e-cigarette users to harmful toxins and carcinogens, like lead, chromium, and even arsenic.

The study, published Wednesday in the scientific journal Environmental Health Perspectives by researchers from Johns Hopkins University's Bloomberg School of Public Health, sampled 56 vape devices. They gathered these e-cigs from actual vapers who they recruited for the study at smoke shops and vape conventions. Prior studies have only looked at newly purchased e-cigs, and the authors of this study wanted to test devices that people actually use for a more representative sample, since they often contain modifications and wear-and-tear.

The study's authors tested three elements of the e-cigs: the liquid itself, the liquid inside of the vape pen's chamber, and the aerosol (or vapor). They were specifically interested in whether the metal coil that vape pens use to heat the liquid in order to turn it into vapor was leeching or generating toxic metals.

And it turns out, their hypothesis was right. There was not a significant amount of toxic metals in the e-cig liquid itself. But in over half of the e-cigs, the liquid inside the dispenser and the aerosol contained significant levels of chromium, nickel, and lead. According to the study's authors, chromium and nickel have been linked to respiratory disease and lung cancer. And lead can cause neurotoxicity and cardiovascular disease — there is also no safe amount of lead exposure.

"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,” study senior author Ana María Rule, PhD, MHS, an assistant scientist in the Bloomberg School’s Department of Environmental Health and Engineering, said in a statement .

Troublingly, the authors also found arsenic in over 10 percent of the sampled e-cigs. Unlike the metals, arsenic was present in the liquid, liquid in the dispenser, and aerosol alike. While the study's authors hypothesize that the metals appear in the e-cig vapor thanks to the metal coils, they do not know how arsenic apparently finds it way into the e-cig refill liquid itself.

I asked some acquaintances who vape what they thought of these findings. These vapers, who preferred not to be named, used to be daily smokers. But they almost entirely vape now; vaping, they have said, is what allowed them to quit cigarettes.

"I'm not really surprised to be honest," one vaper said. "I never expected them to be good for me."

"My question is why is arsenic a necessary ingredient," said another. "I would love to understand why these toxins are remotely necessary."

Cigarettes, of course, also contain toxins including lead and arsenic — with the hugely unhealthy bonus of inhaling burnt tobacco, which itself is damaging to the lungs. And several studies have shown that vaping is far healthier than smoking. One showed that vapers have far fewer toxic substances in their bodies than smokers; another suggested that the cancer risk of vaping is one percent of smoking's cancer risk. However, a study that claimed vaping was 95 percent healthier than smoking was widely criticized. And study author Dr. Ana María Rule sees a comparable risk in terms of metal exposure between e-cigs and cigarettes.

"We found the emission rates were similar between cigarettes and e-cigarettes for elements like chromium, nickel, zinc, lead and silver (all toxic to the lung)," Dr. Rule told Mashble over email. "We found lower concentrations in e-cigarettes for cadmium and arsenic."

Plus, comparing e-cigs to cigarettes is complicated. Dr. Rule said cigarette risk is easier to quantify, because they can measure risk by cigarette. With e-cigs, risk is studied by a designated amount of puffs, which may or may not represent an accurate unit for any given user.

Furthermore, comparing vaping to cigarettes was not the study's authors' primary aim.

"We know there are many young vapers that have never smoked," Dr. Rule said. "A better comparison for them is to breathing ambient air, so for them this represents an increase in risk."

The study's authors hope that their findings will prompt the FDA to regulate e-cigs for the presence of these toxic chemicals, as evidence mounts that vaping is not a risk-free endeavor.

"Our results add to the existing evidence that e-cigarettes are a relevant source of exposure to a wide variety of toxic metals," the study's authors write. "Due to potential toxicity resulting from chronic exposure to metals in e-cigarette aerosols, additional research is needed to more precisely quantify metal exposures resulting from e-cigarette use and their implications for human health, and to support regulatory standards to protect public health."