If you vape — and especially if it's because you think it's a less harmful alternative to smoking — then we have some really bad news.

New research from the University of California, Davis, shows that some popular disposable vapes contain levels of toxic metals so appalling that they exceed traditional cigarettes. And we don't just mean a single cig — we're talking packs of them.

The work, published as a study in the journal ACS Central Science, sounds the alarm on the vast amounts of unregulated if not illegal disposable vapes in the US that remain a favorite of teens.

"When I first saw the lead concentrations, they were so high I thought our instrument was broken," study coauthor Mark Salazar, a researcher at UC Davis, said in a statement about the work.

For their study, the researchers focused on vapes from three popular brands: ELF Bar, Esco Bar, and Flum Pebble. The tests involved activating the vapes and creating between 500 to 1,500 puffs for each one and analyzing the vape clouds. Afterwards, they disassembled the vapes to see where the contaminants were coming from.

The findings were immediately alarming.

Salazar and his colleagues discovered concentrations of toxic forms of metals like nickel, chromium, and antimony in most of the tested vapes.

To quickly sum up what makes these metals bad: the type of nickel the researchers detected can cause lung and nasal cancer; chromium is also considered a carcinogen; and antimony can lead to heart and lung problems when inhaled as a dust and cause vomiting when swallowed.

That brings us to lead. Two vapes from Esco Bar were absolutely reeking with it; on average, the devices from this brand emitted more lead in the first 200 puffs than smoking twenty packs of cigarettes.

The contamination appears to be caused both by the components of actual vape and the nicotine juice they contain.

"We found that these disposable devices have toxins already present in the e-liquid, or they're leaching quite extensively from their components into e-liquids and ultimately transferred to the smoke," Salazar said.

Overall, two of the vapes emitted enough nickel and antimony levels to exceed cancer risk limits, the researchers said, while four vapes had nickel and lead emissions severe enough to be considered a risk for causing neurological damage and respiratory diseases.

Bear in mind that this is what the researchers found by testing just three of some of the most well-known disposable vape brands. There are hundreds of other brands out there of even murkier origins, most imported from China. And while we're still only beginning to grapple with their health hazards, the findings line up with other research, including a study last year that found elevated uranium and lead levels in the urine of teens who regularly vaped.

"Our study highlights the hidden risk of these new and popular disposable electronic cigarettes — with hazardous levels of neurotoxic lead and carcinogenic nickel and antimony — which stresses the need for urgency in enforcement," said senior author Brett Poulin, an assistant professor in the UC Davis Department of Environmental Toxicology, in the statement.