Scientific study finds high levels of toxic metals in some disposable e-cigarettes

A study recently published in the journal ACS Central Science challenges the claim that e-cigarettes are a "healthy" alternative to traditional cigarettes. Conducted by researchers from the Department of Environmental Toxicology at UC Davis, it found surprisingly high concentrations of toxic metals and metalloids in the vapor of five devices from three of the 100 popular disposable e-cigarette brands: Esco Bar, Flum Pebble, and ELF Bar (the most popular e-cigarette brand among teens and young adults in 2023 and 2024, according to the CDC).[1].

Some disposable e-cigarettes are particularly toxic

According to a study from the University of California, Davis, some disposable e-cigarettes and pods release more toxic metals after a few hundred puffs than older e-cigarette models or even traditional cigarettes.

The study found that the disposable e-cigarettes tested could release significantly more lead than traditional cigarettes. Specifically, 200 puffs of an Esco Bar were found to release four to thirteen times more lead than a pack of 20 cigarettes.

These results have led researchers to sound the alarm. Despite strict FDA controls on the sale of these devices in the United States, which prohibits sugary flavors and sales to minors, these devices remain widely available, particularly to adolescents and young adults. Although they are particularly vulnerable to lead exposure, they are attracted by the colorful and playful packaging of these products.

The results show that the presence of nickel and antimony in the vapors of three of the tested devices exceeded the carcinogenic risk thresholds. Four devices also released enough lead and nickel to pose a neurological and respiratory risk, independent of the cancer risks.

Heavy metals in steam: lead, nickel, antimony, etc.

The study, led by the team of Professor Brett Poulin, assistant professor in the Department of Environmental Toxicology at UC Davis, revealed that these e-cigarettes contain alarming levels of lead. Lead is neurotoxic and is associated with lung, kidney, and brain cancers. Nickel and antimony, which are associated with nasal and sinus cancers, were also identified. Doctoral student Mark Salazar, the study's first author, initiated the research after analyzing a friend's e-cigarette: " The lead levels were so high that I thought our measuring device was faulty. ".

The researchers tested seven disposable models from three popular brands, generating between 500 and 1,500 puffs per device. The results indicated that some devices released very high amounts of antimony and lead in the vapor; that levels of chromium, nickel, and antimony increased with the number of puffs; and that most of the disposable e-cigarettes tested released significantly more toxic metals than older rechargeable models.

By disassembling the devices, they discovered that the metals come either directly from the liquid or from internal components that release toxic substances into the liquid, which are then inhaled by the vaper. Some bronze alloy parts contain lead, the heating elements release nickel, and antimony is already present in high doses in the liquids.

Public health experts are calling for stricter regulation of these products, or even a ban on them.

Researchers are calling for urgent regulation of these products, particularly given their widespread popularity among young people and their availability. Moreover, they are often marketed without FDA approval. The market is evolving faster than science, and few studies exist on these new devices. This leaves consumers and authorities poorly informed about the real dangers.

Prof. Brett Poulin commented: “ Our study highlights the hidden risk of these new, popular disposable e-cigarettes, which contain dangerous levels of neurotoxic lead and carcinogenic nickel and antimony, underscoring the need for urgent enforcement. ".

The team emphasizes that larger studies are needed, and future work should include more brands and explore whether flavorings, nicotine levels, shelf life, and storage can affect the release of these metals. Laboratory studies and animal experiments are also needed to track long-term effects, including whether non-toxic chromium can convert to its carcinogenic form once inhaled into the lungs.

According to sales data reported by Reuters, $2.4 billion worth of illegal e-cigarettes were sold in the United States in 2024, despite being unregulated and untested by a monitoring agency. This study also highlights the diversity of vaping products and their health effects. According to the latest CDC data, approximately 6% of American adults, or about 17 million people, use vaping products. About 6% of high school students report vaping at least once in the past 30 days.[2][3].

A practice that is all the more worrying since, according to a US study conducted in May 2025, 3.6 % of US high school students combined the use of nicotine pouches and e-cigarettes in 2024, further increasing the risks of health problems and addiction.

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[1]R. Salazar M., Saini L., B. Nguyen T., E. Pinkerton K., K. Madl A., M. Cole A., and A. Poulin B., “Elevated Toxic Element Emissions from Popular Disposable E-Cigarettes: Sources, Life Cycle, and Health Risks”, ACS Central Science, June 25, 2025, https://pubs.acs.org/doi/10.1021/acscentsci.5c00641

[2]Arrazola RA et al., Tobacco Product Use Among Adults — United States, 2017–2023, US Department of Health and Human Services, Centers for Disease Control and Prevention, MMWR, published March 6, 2025, Vol. 74, No. 7

[3]Park-Lee E et al., E-Cigarette and Nicotine Pouch Use Among Middle and High School Students — United States, 2024, US Department of Health and Human Services, Centers for Disease Control and Prevention, MMWR, published September 5, 2024, Vol. 73, No. 35

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