As the number of people using e-cigarettes wafts upward, health experts and researchers are scrambling to understand their health effects and the usage trends of the nicotine-vaporizing gadgets. Though many hope that e-cigarettes will offer smokers a healthier option and a path to quitting, experts fear their effects on children and adolescents.

Today, the American Academy of Pediatrics (AAP) is officially recommending that only people 21 years and older be allowed to buy e-cigarettes, or “electronic nicotine delivery systems” (ENDS), and all other tobacco products. “The increasing use of ENDS among youth threatens five decades of public health gains in successfully deglamorizing, restricting, and decreasing the use of tobacco products,” the organization stated as part of a series of policy recommendations published in Pediatrics.

For adult smokers who switch entirely to e-cigarettes, “there’s little doubt that their health will be improved,” Tom Frieden, director of the Centers for Disease Control and Prevention, said during a recent presentation on e-cigarettes held by the agency. “On the other hand, if adolescents who would not have become smokers begin using e-cigarettes, there is a high likelihood that their risk of using combustible tobacco will be greater."

Though the use of traditional tobacco products by youth is on the decline, the number of teenagers that use e-cigarettes—vape—is rising. In 2014, 13.4 percent of high school students and 3.9 percent of middle school students reported vaping at least once in the past 30 days. Both numbers represent about a three-fold increase from 2013, the CDC noted. In a couple of small-scale studies, non-smoking adolescents and young adults who used e-cigarettes were more likely to start smoking combustible cigarettes than their non-vaping peers.

Researchers fear that e-cigarettes, which can deliver adjustable doses of nicotine, may hook kids for life and threaten their health. Nicotine is highly addictive and has neurotoxic effects on the developing adolescent brain, pediatricians note. And for younger kids who may get ahold of e-cig ingredients, as little as a teaspoon of liquid nicotine can be fatal.

In addition to the risks of nicotine exposure, vaporizing liquid and flavorings also raise concern. Some liquids may include contaminants such as metals and formaldehyde. Flavorings like as cotton candy, peanut butter cup, banana cream pie, and sour blue raspberry are based on additives that are considered safe in food, but little data exist for inhalation safety.

With the safety concerns and worrying trends in usage data, pediatricians and others are clamoring for restrictions. In the United States, there are currently no federal restrictions on e-cigarettes, though many states have moved to regulate them. In April 2014, the US Food and Drug administration proposed to regulate ENDS as it does traditional tobacco products. This includes setting taxes, age restrictions, and bans on advertising and flavoring that appeal to kids.

Last week, the agency sent their proposal to the White House Office of Management and Budget for review. That office has 90 days to look it over.

Pediatrics, 2015. DOI: 10.1542/peds.2015-3222 (About DOIs)