Starting next year, Hawaii will become the first state in the nation to ban smoking for people under 21. Gov. David Ige (D) signed the historic legislation on Friday, which imposes fines on underage smokers and those who provide them with tobacco products.

Blame e-cigarettes. Hawaii’s lawmakers are alarmed at the growing popularity of these battery-powered vaporizers, which deliver a mist laced with nicotine, the active drug in tobacco.

In the bill, they cite concerning statistics about the devices: “According to recent figures from six Hawaii high schools, among the ninth and tenth grade students, twenty-nine percent have used electronic smoking devices at least once and eighteen percent use them regularly,” they write, referencing a study from the University of Hawaii.

According to the state’s department of public health, the number of Hawaii high school students who have ever used an e-cigarette tripled between 2011 and 2013, Nationwide, e-cigarettes have become more popular than regular cigarettes among high school students, the Centers for Disease Control and Prevention reported in April.

Public health advocates say these trends are troubling because nicotine is highly addictive and may be especially harmful to adolescent brains. Since smoking is such a hard habit to break (just ask President Obama), one of the best ways to quit is to never start.

“I’ve treated so many adults who are desperate — desperate — to get off tobacco. They all started as kids,” CDC Director Tom Frieden told the Los Angeles Times last year. “I see the [e-cigarette] industry getting another generation of our kids addicted.”

Research shows that nearly 90 percent of adult smokers began smoking before they were 18, typically by bumming smokes from older friends. Though every state bans cigarette sales to minors, many high school seniors are old enough to legally buy tobacco, which they can pass on to their classmates.

Raising the smoking age to 21 would put cigarettes out of reach of high-school social circles. Fewer teens trying tobacco would mean fewer adults addicted to smoking. The Institute of Medicine estimates that raising the smoking age to 21 would lead to a 12 percent decrease in the smoking rate by the time today’s teens grew up.

Though the high-school smoking rate plummeted in the late 1990s, there hasn’t been much change in the past four years, according to the CDC. Though cigarette and cigar smoking is down, e-cigarette and hookah use is way up.

All of these are ways to deliver the addictive drug nicotine. Yet, many regard e-cigarettes are cleaner and perhaps safer than regular cigarettes because nothing is burned. Instead of a smoke that has been demonstrated to cause cancer and lung disease, e-cigarettes put out a chemical mist.

But this vapor carries its own cancer-causing agents, in quantities that may pose health risks — there is still little information on the long-term health effects of e-cigarette use.

(It should be noted, though, that some e-cigarettes can be used with nicotine-free liquid, just as there exist herbal cigarettes which don’t contain tobacco.)

While e-cigarettes are still a tiny fraction of the U.S. tobacco market, they’re a fast-growing part of an industry that has seen broad declines in regular cigarette use. The Big Three tobacco companies have embraced the technology in recent years, buying up existing e-cigarette makers or launching their own products.

An added advantage is that existing tobacco laws have not fully caught up.

Most states don’t tax e-cigarettes as heavily as regular cigarettes. Some states are just now starting to ban them from public indoor spaces (Hawaii passed such a law this year, becoming the fourth state to do so). And in 10 states, e-cigarettes are so unregulated that even children can buy them.

Last year, the FDA proposed rules that would ban e-cigarette sales to minors and force companies to attach health warning labels. But those rules have not yet been implemented.

So at present, states have been left to their own devices, so to speak.

In Hawaii, the booming popularity of e-cigarettes has backfired for tobacco companies. If the devices had not been so fashionable among high school students, state legislators might not have been motivated to act.

But now, in a victory for anti-smoking advocates, Hawaii’s teens will have to wait a few more birthdays before they can buy cigarettes of any kind — electronic or old-fashioned. The hope is that many will never pick up the habit at all.