Metals found in disposable e-cigarette vapor could pose health risks

Brightly colored inexpensive and disposable electronic cigarettes and vapes continue to gain popularity. These devices turn flavored nicotine-containing liquid into a vapor that people inhale over hundreds or thousands of puffs — commonly called vaping. Researchers report in ACS Central Science that after a few hundred puffs, some disposable vaping devices released higher amounts of metals and metalloids than older refillable e-cigarettes and traditional cigarettes, thereby raising a user’s risk of health problems.

“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,” says Brett Poulin, the corresponding author of the study from the University of California, Davis.

Studies on early generations of refillable e-cigarettes (e.g., refillable pens, box mods and pods) found that their heating components could release metals such as chromium and nickel ions into the internal liquid that then becomes the vapor people breathe. Inhaling certain metals and metalloids is potentially harmful, increasing a person’s risk of cancer, respiratory disease and nerve damage.

Although marketing of most disposable e-cigarettes is not authorized by the U.S. Food and Drug Administration, the devices remain widely available. In the past few years, disposable e-cigarette sales have overtaken sales of older refillable vapes, but little is known about the elemental composition of vapors from the newer devices. So, Poulin and colleagues assessed popular disposable e-cigarette brands to evaluate the potential health risks they could pose to a user.

The researchers first identified the metal and metalloids inside seven disposable devices from three brands, comparing liquids with light and heavy levels of flavoring. The original unused liquids had low levels of ionic metals and metalloids, though some devices had surprisingly high levels of lead and antimony. The team traced the source of lead to leaded copper alloys used for non-heating components, which leach into the e-liquid. Antimony did not have a definable source.

Then they activated the disposable e-cigarettes, which heated the internal liquid and created between 500 and 1,500 puffs for each device. Analyses of the vapors determined that:

• The levels of ionic metals and metalloids including chromium, nickel, and antimony increased as the number of puffs increased, whereas concentrations of ionic zinc, copper, and lead were elevated at the start, and each device had different emissions.
• Compared with previous studies, most of the tested disposable e-cigarettes released higher amounts of metals and metalloids into vapors than older refillable vapes.
• One of the disposable e-cigarettes studied released more lead during a day’s use than nearly 20 packs of traditional cigarettes.

The researchers next assessed the health risk faced by a daily user of these devices. For two of the disposable vapes, the team collected toxicity information for chromium and antimony, substances that have non-toxic and carcinogenic forms. Only the non-toxic form of chromium, Cr(III), was present, but a mixture was observed between the less toxic form of antimony, Sb(V), and the carcinogenic form, Sb(III), in the vapors. However, nickel levels in vapors from three devices and Sb(III) levels in vapors from two devices exceeded cancer risk limits. The vapors from four of the devices had nickel and lead emissions that surpassed health risk thresholds for diseases other than cancer.

The researchers tested only three of the nearly 100 disposable e-cigarette brands available on store shelves. They say the results are concerning because of the current popularity and extensive use of disposable e-cigarette products, especially among adolescents and young adults.

The authors acknowledge support from the University of California Tobacco-Related Disease Research Program, the National Institute of Environmental Health Sciences T32 training program, and the California Agricultural Experiment Station.

The paper’s abstract will be available on June 25 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acscentsci.5c00641

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