Atlanta — A new study has brought the public health concern of vaping back to the forefront. Electronic cigarettes have already been branded unsafe for kids, teens and young adults by the Atlanta-based Centers for Disease Control and Prevention, and new evidence has linked the vapes to possible increased exposure of harmful heavy metals.

Most vapes contain nicotine, which is highly addictive and damaging to adolescent brain development. Some vape aerosol flavorings also may be unsafe to inhale, according to the CDC. Some contain diacetyl, a chemical linked to lung disease, or cancer-causing chemicals.

The recent study, published in the journal Tobacco Control, analyzed urine samples from 200 U.S. adolescent e-cigarette users to determine how vaping frequency and vape flavor types affected their heavy metal levels.

The researchers discovered teens who vaped intermittently had urine levels 40% higher in lead than occasional users, as reported by CNN. E-cigarette users who preferred sweet flavors also had urine levels higher in uranium.

“E-cigarette use during adolescence may increase the likelihood of metal exposure, which could adversely affect brain and organ development,” according to the study. “These findings call for further research, vaping regulation, and targeted public health interventions to mitigate the potential harms of e-cigarette use, particularly among adolescents.”

Dr. Lion Shahab, professor of health psychology at University College London and co-director of the UCL Tobacco and Alcohol Research Group, praised the study for being well-conducted but cautioned that its results needed to be seen in context. Simply put, more research is needed.

“This study therefore cannot tell us anything about absolute increase in exposure to heavy metals from e-cigarette use in this population, only about relative exposure among less and more frequent e-cigarette users,” Shahab, who was not affiliated with the study, said in a news release.

“Given that heavy metal exposure is mostly driven by the type of device used, future studies should investigate whether there are any meaningful differences between different e-cigarette types to inform regulators, e.g., to curtail use of devices that expose users to more heavy metals. The relatively small sample size in this study meant that this issue could not be investigated.”