Rhiannon Griffith-Bowman smokes an e-cigarette in San Rafael, Calif. A study released Thursday shows that the popularity of e-cigarettes has grown dramatically among teenagers. (Justin Sullivan/Getty Images)

The number of middle and high school students using electronic cigarettes tripled from 2013 to 2014, according to government figures released Thursday, a startling increase that public health officials fear could reverse decades of efforts combating the scourge of smoking.

The popularity of e-cigarettes among teenagers now eclipses that of traditional cigarettes, the use of which has fallen to the lowest level in years.

Tom Frieden, director of the Centers for Disease Control and Prevention, called the spike in ­e-cigarette use “shocking.”

“It’s a really bad thing, and it is subjecting another generation of our children to an addictive substance,” he said in an interview, adding that any type of nicotine exposure can harm the teenage brain and that some e-cigarette smokers undoubtedly will go on to use traditional cigarettes.

Not everyone sees such cause for alarm in the new numbers.

“The CDC should really be jumping for joy at the fact that smoking rates are declining. This is a huge success,” said Michael Siegel, a professor and tobacco-control specialist at Boston University’s School of Public Health. “Instead, they are using this as another opportunity to demonize e-cigarettes.”

Siegel said he agrees that minors shouldn’t have access to any tobacco product. But he said the CDC numbers suggest that rather than serving as a gateway to cigarette smoking, e-cigarettes actually might be diverting teens from traditional cigarettes, which still account for nearly half a million tobacco-related deaths in the United States each year.

Thursday’s findings came as little surprise to many educators around the country, who have increasingly wrestled with how to handle the swift rise in e-cigarette use among students.

Patricia Sheffer, superintendent of the Union County school system in Kentucky, grew so frustrated this year over the dozens of incidents of students being caught with e-cigarettes that last month she sent a recorded message to district parents and posted a plea on Facebook asking for help cracking down on the problem. The dogs that perform a sweep of the schools about once a month also are being trained to sniff out ­e-cigarettes, she said.

“It’s just growing at such a rapid pace,” said Sheffer, who worries about the various substances students might be smoking in the devices. “I thought, ‘We have to take a stand.’ ”

School districts around the country, such as in North Carolina’s Haywood County, are classifying e-
cigarettes as drug paraphernalia
, rather than as normal cigarettes, in hope that the more severe penalties will discourage students from bringing the devices to campus.

“It was to send a message that we don’t want it,” said Associate Superintendent Bill Nolte.

Anti-smoking advocates insist the rise in the popularity of ­e-cigarettes stems in part from aggressive marketing campaigns that Frieden called “straight out of the playbook” of ads that targeted young people in earlier generations.

E-cigarettes remain unregulated by the federal government, ­although numerous cities and states have passed laws restricting sales to minors and banning the devices in public places. But e-cigarettes do not face the same federal restrictions on television and radio advertising that apply to traditional cigarettes.

“These are the same images, the same themes and the same role models that the cigarette industry used 50 years ago,” said Matthew Myers, president of the Campaign for Tobacco-Free Kids. “It’s the Marlboro Man reborn. It’s the Virginia Slims woman re-created, with the exact same effect. . . . This is not an accident.”

Cynthia Cabrera, executive director of the Smoke-Free Alternatives Trade Association, an industry group, said her organization supports banning sales to minors and disputed that e-cigarette companies are deliberately marketing to teens. She said that while tobacco giants with huge advertising budgets such as Lorillard and Altria have purchased e-cigarette companies in recent years, most e-cig marketing is still done by hundreds of small companies whose target audience is smokers looking for less-toxic options.

“If you’re thinking this is Big Tobacco redux, that’s the wrong thinking,” she said.

At the heart of the public health debate lies a series of unanswered questions: Are ­e-cigarettes unequivocally less harmful than tar-laden, chemical-filled tobacco cigarettes, as many people assume? Will they prove to be a healthier alternative that helps people avoid cigarette smoking and reduce tobacco-
related deaths, or simply devices that could undermine decades of public health efforts?

Siegel, the Boston University professor, said it “shouldn’t take a rocket scientist” to figure out that “vaping” is safer than smoking, given that the liquids used in e-
cigarettes involve no combustion and very few chemicals. Likewise, Cabrera said regulators shouldn’t “lose perspective about the potential” for e-cigarettes to eliminate harm caused by smoking cigarettes.

But plenty of uncertainty remains. A study published this week in the journal Tobacco Control, for instance, found that the chemicals used to flavor e-cigarettes could prove unsafe when inhaled over time. Public health officials say far more research is needed given how little data exists on the long-term effects of e-cigarettes.

This much seems certain from Thursday’s results, based on an annual survey of 22,000 students around the country: Teens are experimenting as much as ever. Roughly a quarter of high school students and nearly 8 percent of middle school students still report having used a tobacco product at least once in the past 30 days.

But from 2013 to 2014, the findings say, e-cigarette use among high school students had increased from 4.5 percent to 13.4 percent. Usage also more than tripled among middle school students, from 1.1 percent to 3.9 percent. Only among black students was another tobacco product — cigars — more popular than ­e-cigarettes, the CDC said.

During that same period, the use of hookahs — water pipes used to smoke specially made tobacco — roughly doubled for middle and high school students, equaling and eclipsing the use of regular cigarettes, respectively.

Meanwhile, the use of conventional cigarettes sank to the lowest levels in years. According to the CDC, 9.2 percent of high school students reported smoking a cigarette over the past month, compared with 12.7 percent a year earlier. Middle school students’ cigarette use dropped to 2.5 percent from 2.9 percent. While some people might see that as good news, anti-tobacco advocates and public health officials remain wary.

“The drop in cigarette use is historic, with enormous public-health significance,” Myers said. But, he quickly added, “the explosion of ­e-cigarette use among kids means these products are being taken up in record numbers with totally unknown long-term consequences that could potentially undermine all the progress we’ve made.”

Last April, the Food and Drug Administration announced plans to begin regulating e-cigarettes, now a multibillion-dollar industry in the United States. The agency said it wants to force manufacturers to curb sales to minors, place health warning labels on the products and disclose their ingredients. The FDA’s initial proposals stopped short of halting online e-cigarette sales, restricting television advertising, or banning candy and fruit flavorings — chocolate, cotton candy, passion fruit, piña colada and hundreds of others — that critics say appeal to young users.

A year later, the FDA has yet to finalize any new regulations involving e-cigarettes, though its top tobacco official said in an interview Thursday that doing so remains “our highest priority.”

“The numbers are astounding,” said Mitch Zeller, director of the FDA’s Center for Tobacco Products, calling the recent jump in youth e-cigarette use a “clarion call” to bring the products under federal oversight. “What this tells us is that with all the progress we’ve made in reducing youth cigarette smoking, that progress is in jeopardy.”

Myers said Thursday’s figures make clear that such action is long overdue, and that it can’t come soon enough.

“The failure of the FDA to move more quickly means we have an urgent crisis that needs to be addressed,” he said. “In the absence of strong governmental action, these numbers will only keep going up.”