Toxic Heavy Metals May Be Present in Vapors From Both E-Cigarettes and Ultrasonic Cigarettes: Study

U-cigarette vapors may contain significantly higher levels of selenium and arsenic than traditional e-cigarettes, researchers have found.

As concerns over lung injuries linked to e-cigarette use continue to grow, new research suggests that a newer generation of vaping devices, known as ultrasonic cigarettes or u-cigs, may release even more dangerous levels of toxic chemicals. 

The findings were published earlier this year in the medical journal Environmental Health Perspectives, indicating that vapors from some u-cigarette brands may contain extremely high levels of toxic heavy metals, such as selenium and arsenic, which could pose health risks for users.

E-cigarettes and u-cigarettes are both devices that can be used instead of traditional cigarettes to ingest nicotine. The main difference between them is that u-cigarettes use high-frequency ultrasonic vibrations to vaporize nicotine-based liquids for inhalation, while e-cigarettes use heating coils to do the same. Some advocates claim this could make u-cigarettes less harmful to users than e-cigarettes.

Regardless of the delivery method, ingestion of toxic heavy metals, such as arsenic, has been linked to numerous health risks, including various neurological conditions as well as different forms of cancer. In recent years, these findings have led to a series of lawsuits over children’s toxic heavy metals poisoning as the result of eating various food products.

In the new study, researchers from the University of California, Riverside examined chemicals found in different brands of u-cigarettes, e-cigarettes and other pod-style nicotine vaporizers.

Led by Esther E. Omaiye, the team used a scanning electron microscope and energy-dispersive X-ray spectrometer to quantify chemicals and metals from various flavors of SURGE u-cigarettes, JUUL e-cigarettes and other brands.

The study identified 16 elements in at least one fluid or aerosol sample from each product. In general, u-cigarettes, including the brand SURGE, had more elements, and at higher levels, compared to aerosols from newer, fourth-generation e-cigarettes.

Researchers also found that element concentrations typically increased in fluids after vaping. Silicon was present in both the fluids and aerosols of all products tested, including SURGE.

Nickel appeared in low levels in all fluid samples as well, except for KWIT Stick, which showed the highest levels of up to 66,050 micrograms per milliliter. However, nickel transferred to aerosols at relatively low efficiency.

SURGE fluids, unlike those from e-cigarettes, also contained copper and zinc, although minimal amounts were found in the aerosols. Notably, SURGE products showed higher concentrations of arsenic and selenium, both of which are on the U.S. Food and Drug Administration’s (FDA) list of “harmful and potentially harmful constituents.”

The study suggests that the presence of arsenic and selenium may be linked to poor-quality solvents used in the e-fluid manufacturing process or to the sonicator heating component in SURGE devices.

“The current study further shows for the first time (to our knowledge) that u-cigarettes have similar and, in some cases, higher concentrations of elements/metals in their fluids and aerosols than e-cigarettes,” Omaiye said. “These data raise concerns about the health risks, such as cancer and neurotoxicity, that could result from long-term use of these products.”

E-Cigarette Concerns

Vaping remains a growing public health concern in the U.S., particularly among teenagers. In response, federal officials are continuing to push for stronger regulations, including restrictions on flavored e-cigarettes.

Last month, the U.S. Supreme Court upheld federal limits on flavored vape products, a move that health officials say is critical to curbing youth nicotine use. Research has linked such restrictions to a 3.6 percentage point drop in daily vaping among young adults.

In addition, agencies like the FDA and the U.S. Centers for Disease Control and Prevention (CDC) continue to support tighter oversight. Some of these efforts appear to be paying off, with the CDC reporting that teen vaping rates fell to a 10-year low in late 2023.