Health Risks of Toxic Metals in Disposable E-Cigarettes Exposed

A recent study from the University of California, Davis (UC Davis) reveals alarming findings regarding disposable e-cigarettes, indicating that these popular vaping devices emit hazardous levels of toxic metals, with some concentrations exceeding established safety thresholds. This research, published in the journal *ACS Central Science* on June 25, 2025, underscores a growing public health concern as disposable e-cigarettes become increasingly popular among youth in the United States.

Disposable e-cigarettes are marketed as convenient, inexpensive, and flavored alternatives to traditional cigarettes. However, they have become the most widely used vaping products among teenagers and young adults, despite the majority lacking approval from the U.S. Food and Drug Administration (FDA). According to Dr. Brett Poulin, an assistant professor at UC Davis and corresponding author of the study, "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."

The study's lead author, Mark Salazar, a PhD candidate at UC Davis, initiated the research after observing a friend using a disposable vape. Curious about the contents, he tested the device and discovered alarming levels of lead (Pb) among other toxic metals. The research team tested seven devices across three leading brands: ELF Bar, Flum Pebble, and Esco Bar, analyzing their emissions from new to end-of-life conditions, simulating up to 1,500 puffs.

The results were striking. The study found that disposable e-cigarettes released significant levels of nickel (Ni), chromium (Cr), antimony (Sb), and lead, with concentrations often increasing with usage. Specifically, lead levels in Esco Bar devices reached up to 175,000 µg per kg, translating to higher lead exposure than from smoking 20 packs of cigarettes. The presence of leaded bronze components in some devices raised concerns about manufacturing practices and consumer safety.

Previous studies have indicated that traditional refillable e-cigarettes can leach metals into vapor; however, the findings on disposable devices suggest even greater risks. Salazar noted, "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."

The health implications of these findings are significant, particularly for young users who may be more vulnerable to toxic exposures. The researchers utilized published toxicity thresholds to assess the cancer and non-cancer risks associated with daily use of these devices. They found that the levels of nickel and antimony raised cancer risks above accepted limits, while lead and nickel levels exceeded safety thresholds for respiratory and neurological effects by as much as nine times.

The study raises vital questions about the regulatory landscape for vaping products. As there are approximately 100 disposable e-cigarette brands on the market, many of which remain untested, this highlights a critical gap in oversight. Dr. Poulin emphasized the urgency for regulatory bodies to act, stating, "These risks are not just worse than other e-cigarettes but worse in some cases than traditional cigarettes."

The researchers advocate for broader studies that encompass a wider variety of brands and investigate the effects of flavors, nicotine levels, and storage conditions on metal release. Future research should also include lab studies and animal models to assess the long-term effects of exposure to these toxic metals, particularly concerning the potential conversion of less harmful forms of chromium into their carcinogenic variants once inhaled.

With the increasing prevalence of disposable e-cigarettes among youth, addressing these public health concerns is imperative. As regulatory frameworks struggle to keep pace with the rapid evolution of vaping products, the need for comprehensive research and timely intervention becomes increasingly critical, ensuring that user safety remains a priority in the growing vaping industry.