Disposable vapes release more toxic elements than tobacco smoke

Despite being illegal in the US, disposable e-cigarettes are still readily available in stores nationwide. Scientists are calling for the federal government to ramp up its enforcement of the ban after the release of a new study showing that single-use vapes release higher concentrations of toxic metals than reusable e-cigarettes and traditional cigarettes do (ACS Cent Sci. 2025, DOI: 10.1021/acscentsci.5c00641).

The researchers found that one of the disposable vapes they studied released more lead during a day’s worth of use than almost 20 packs of tobacco cigarettes. “When I analyzed the metals in the aerosols, I quantified lead at such extreme concentrations that I thought my instrument was broken,” says Mark R. Salazar, one of the study’s authors and a PhD candidate in Brett A. Poulin’s environmental toxicology lab at the University of California, Davis.

Salazar and his colleagues used a specially designed vacuum to draw the vapor out of disposable vapes, then captured the aerosol on filters and analyzed the chemical contents. They carried out this process until the devices stopped working.

Lead was found in aerosols at concentrations as high as 51.9 parts per million (ppm); the team also found high concentrations of nickel (19 ppm), copper (24 ppm), zinc (87 ppm), chromium (4.9 ppm), and antimony (2.3 ppm). This level of exposure is “deeply concerning, especially given that the target market for these products is typically young people and teenagers,” says Jonathan H. Shannahan, a toxicologist at Purdue University who was not involved in the study. Inhaling these elements has been linked to a higher risk of developing cancer, cardiovascular disease, and neurotoxicity, he added.

The study authors also looked at the oxidation state of some of the elements because that in part dictates their toxicity. Those data were relevant for antimony, which was present in the aerosols in its toxic +3 oxidation state and was more plentiful in flavored vapes than plain ones. Although the scientists detected chromium, the element was not in its highly toxic +6 form.

The longer the devices were used, the greater the concentration of the elements in the aerosols became. For example, chromium and nickel increased by almost 1,000-fold over a disposable e-cigarette’s life.

The researchers took the devices apart to investigate which of their unused components contained heavy metals. They discovered that some of the toxic chemicals were present in the e-liquid before the vape has been used. Metals may have leached into the e-liquid from other parts of the device, such as the heating coil or the electronics, to ultimately end up in the aerosol.

“One of the brands used a lead alloy as a nonheating metallic component,” Poulin says. “We speculate in the paper that it’s just a cheap metal that they put in devices, but those cheap metals apparently dissolve in the presence of the e-liquid.”

Najat Saliba, an atmospheric chemist at the American University of Beirut who was not involved with the study, says the contents of the e-liquid could also be acting as a catalyst to the leaching process. “Certain flavoring agents may enhance the dissolution of metals from heating coils into e-liquids, likely due to chemical interactions with metal surfaces,” she says.

For Salazar and Poulin, the take-home message of their study is clear: government and regulatory agencies need to act. “These devices are already not authorized for sale,” Poulin says. “This is a call for enforcement.”