The U.S. surgeon general is calling e-cigarettes an emerging public health threat to the nation’s youth.

In a report being released Thursday, Surgeon General Vivek Murthy acknowledged a need for more research into the health effects of “vaping,” but said e-cigarettes aren’t harmless and too many teens are using them.

“My concern is e-cigarettes have the potential to create a whole new generation of kids who are addicted to nicotine,” Murthy told The Associated Press. “If that leads to the use of other tobacco-related products, then we are going to be moving backward instead of forward.”

Battery-powered e-cigarettes turn liquid nicotine into an inhalable vapor without the harmful tar generated by regular cigarettes. Vaping was first pushed as safer for current smokers. There’s no scientific consensus on the risks or advantages of vaping, including how it affects the likelihood of someone either picking up regular tobacco products or kicking the habit.

Federal figures show that last year, 16 percent of high school students reported at least some use of e-cigarettes — even some who say they’ve never smoked a conventional cigarette. While not all contain nicotine, Murthy’s report says e-cigarettes are the most commonly used tobacco-related product among youth.

Nicotine is bad for a developing brain no matter how it’s exposed, Murthy said.

“Your kids are not an experiment,” he says in a public service announcement being released with the report.

It’s already illegal to sell e-cigarettes to minors. Earlier this year, the Food and Drug Administration issued new rules that, for the first time, will require makers of nicotine-emitting devices to begin submitting their ingredients for regulators to review. The vaping industry argues the regulations will wipe out small companies in favor of more harmful products, and likely will lobby the incoming Trump administration to undo the rules.

Murthy’s report calls on parents and health workers to make concerns about e-cigarettes clear to young people. He said local officials should take action, too, such as including e-cigarettes in indoor smoke-free policies.

(AP)