The rise in popularity of disposable vapes among teens and young adults comes with potential health risks that are still being researched.

A study published on June 25 from the University of California–Davis found that disposable vapes from three of the most popular brands on the market—Esco Bar, Flum, and ELF Bar—release more toxic metals than other kinds of e-cigarettes and, in some cases, traditional cigarettes.

Researchers found “hazardous levels” of lead, nickel, and antimony emissions in the vapor, which in some devices exceeded risk limits for cancer and other illnesses such as neurological damage and respiratory diseases, according to a university report.

One of the vapes in the study was found to release more lead in a single day’s use than nearly 20 packs of cigarettes.

“When I first saw the lead concentrations, they were so high I thought our instrument was broken,” researcher Mark Salazar said in the report, referring to the first disposable vape pod he tested.

These initial test results led Salazar and other researchers to look more closely into just what users are inhaling through vapes.

Disposable vapes work by using a battery-powered heating coil to heat the e-liquid and produce vapor to be inhaled.

During testing, researchers used an instrument to create between 500 and 1,500 puffs per device. They found that most of the vapes tested released vapor that contained “markedly higher” amounts of metals than refillable vapes. The study also shows that levels of hazardous metals increased the more each vape was used.

Researchers took the vapes apart to identify the source of the metals present in the vapor. They found that there was already antimony present in the e-liquid and that the components in certain vapes leached nickel and lead into the e-liquid as well. The heating coils were also found to release nickel.

“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,” senior author Brett Poulin said in the report.

Vapes are marketed as a safer alternative to cigarettes. An article from Yale describes how advertisements tailored toward younger audiences feature vapes in “trendy shapes, vivid colors, and endless flavors.”

E-cigarettes were the most commonly used tobacco product among U.S. middle and high school students in 2024, according to a report from the Centers for Disease Control and Prevention (CDC).

The CDC report states that 7.8 percent of high school students and 3.5 percent of middle school students reported currently using e-cigarettes. Among the e-cigarette users, 55.6 percent used disposable ones.

Youth vaping has recently seen a decrease; however, the CDC found that half a million fewer young people reported that they currently used e-cigarettes in 2024 than in 2023, marking the lowest level in a decade.

In California, the sale of most flavored tobacco products, including flavored e-cigarettes, was banned by state law in 2022. Teens in the state are still able to get their hands on flavored vapes online, however, as a 2024 study from the University of California–San Diego found that online retailers overlooked rules against selling vapes to minors and neglected requirements such as age verification.

The UC–Davis report concludes that the study highlights the need to enforce laws about e-cigarettes and to continue researching the public health implications of these products.

Researchers Mark Salazar (L) and Brett Poulin in a lab with disposable vape pods. (Courtesy of Kat Kerlin, UC Davis)