Vaping instead of smoking still exposes you to toxic metals like lead - here's how worried you should be

• A new study found that people who vape may be inhaling potentially dangerous levels of toxic metals like lead.
• However, the study did not directly compare the levels to those of conventional cigarettes - which some research suggests are higher and more worrisome.
• Most research suggests that vaping is a healthier alternative to smoking - especially for adults who want to quit. But those studies have also revealed some of its potential downsides.

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Smoking kills. No other habit has been so strongly tied to death. In addition to inhaling burned tobacco and tar, smokers breathe in toxic metals like cadmium and beryllium as well as metallic elements like nickel and chromium - all of which accumulate naturally in the leaves of the tobacco plant.

It's no surprise, then, that most of the available evidence suggests that vaping, which involves puffing on vaporized liquid nicotine instead of inhaling burned tobacco, is at least somewhat healthier.

Still, we don't have a ton of research on how vaping affects the body and brain. It's been less than a decade since the first vape pen hit store shelves as a bulky device the size of a whiteboard marker. Since then, countless varieties of e-cigarettes have become available, from slim black sticks with tips that light up like conventional cigarettes to chrome cartridges that allow the user to personalize everything from the amount of nicotine in each hit to the length of a pull.

In 2015, a group of researchers from medical schools across the globe decided to find out just what was inside the vapors that e-cig users were inhaling. Trapped deep inside the fine aerosol particles that vapers breathe in, the scientists found some of the same toxic metals and metallic elements found in conventional cigarettes - including cadmium and nickel. They also found potentially unsafe levels of several other dangerous substances, like arsenic, chromium, and manganese.

They published their findings this week in the journal Environmental Health Perspectives.

"These heating coils, as currently made, seem to be leaking toxic metals - which then get into the aerosols that vapers inhale," Ana María Rule, the lead author on the study and an assistant scientist in the Bloomberg School's Department of Environmental Health and Engineering, said in a statement.

Despite these findings, it remains unclear what inhaling these levels of substances does.

"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.

Some of the same toxic metals that can be found in cigarettes were also found in e-cigs

Tobacco plants are sponges for toxic substances. As they grow, their roots suck up a range of metals and metallic elements that have accumulated for years in the soil. Those chemicals quickly make their way into the leaves of the plant, where they collect until the tobacco is burned in cigarettes and released into smokers' lungs.

When e-cigarettes first hit store shelves, many users assumed the devices would be free of these chemicals, providing a clean delivery mechanism for the single drug they wanted to be inhaling: nicotine.

The new study, which involved recruiting 56 daily e-cig users from Baltimore and testing their devices in a lab at the Johns Hopkins Bloomberg School of Public Health, suggests that these devices may not be so simple.

In fact, users appear to be inhaling toxic substances like lead, nickel, chromium, and manganese in concentrations that either approached, met, or exceeded the limits defined as safe by the Environmental Protection Agency. Consistently inhaling high levels of these metals has been tied to health problems with the lungs, liver, immune system, heart, and brain, as well as some cancers, according to the US Department of Labor's Occupational Health and Safety Administration.

But since the study did not set out to directly compare the levels of toxic metals in vape pens with those in cigarettes, it's unclear just how both products stack up.

The problem seems to emanate from the heating process that's needed to vape. After comparing the levels of lead in the e-liquids before being heated against the levels present in the heated liquids and the levels in the aerosols, the scientists found concentrations that were 25 times greater in the aerosols.

"The actual levels of these metals varied greatly from sample to sample, and often were much higher than safe limits," Rule said.

We need more research on regular vapers, rather than simply on devices as sold in stores

Most research surrounding e-cigs has focused on so-called cigalikes, first-generation devices that look like regular cigarettes and include a disposable mechanism that's preloaded with e-liquid.

But people who vape every day typically use reusable devices that they can tweak to match their preferences. These devices, known as mods or "tank-style" devices, come with a battery and a mouthpiece and include a tank that can be refilled with e-liquid.

Nailing down the precise health effects of these devices is a tall order - the outcomes could vary just as much as the devices do, with users being able to modify everything from the nicotine content to the heat and inhalation time. But researchers will need to tackle this obstacle before we know the real effects of these devices.

"Direct sampling from e-cigarette consumers rather than purchasing e-cigarettes from a store or company is thus needed to assess typically used devices," the researchers write in their paper.

The largest report on the health effects of vaping still suggests that toxic substances in e-cigs are lower than in regular cigarettes

According to a large recent report on the health effects of vaping from the National Academies of Sciences, Engineering, and Medicine, using e-cigarettes can still be a helpful tool for adults looking to quit smoking. One of the reasons is because the report found substantial evidence that vaping exposes people to what they called "significantly lower" amounts of potentially toxic substances.

But while adults may use e-cigs as a tool to quit smoking, young people may end up using them as a way to start, the authors of the new recent report concluded.

"E-cigarettes cannot be simply categorized as either beneficial or harmful," David Eaton, the chair of the committee that wrote the report and the dean and vice provost of the Graduate School of the University of Washington, Seattle, said in a statement.

Eaton said that in certain circumstances - such as when teens use them and become addicted to nicotine - e-cigarettes "adverse effects clearly warrant concern." But in other cases - like when adults turn to e-cigs to quit smoking - "they offer an opportunity to reduce smoking-related illness."

"Given their relatively recent introduction, there has been little time for a scientific body of evidence to develop on the health effects of e-cigarettes," the authors write in their report.