Attorneys general in more than a dozen states are using state and local laws to pressure the e-cigarette industry to stop marketing to minors, according to Reuters.

The attorneys general of states including California, New York, Indiana and Ohio are applying pressure at all levels, from large tobacco companies to neighborhood vape shops, the article notes.

Their campaign has accelerated since government researchers published a report in April that found e-cigarette use among teens tripled from 2013 to 2014. An estimated 13 percent of high school students used e-cigarettes last year—compared with 9 percent who smoked traditional cigarettes.

“The key is to avoid another generation being addicted to nicotine,” said Indiana Attorney General Greg Zoeller.

In August 2014, a group of 29 state attorneys general urged the Food and Drug Administration (FDA) to impose restrictions on e-cigarettes. They asked for a ban on television ads and on candy and fruit flavors. In April 2014, the FDA proposed regulations that would prohibit e-cigarette sales to anyone under 18, but did not ban ads, online sales or candy or fruit flavors.

The FDA proposal is still under review. E-cigarette use remains legal for minors in states that have not passed laws banning it. While the FDA is likely to finalize its e-cigarette regulations later this summer, it could be several years before the federal rules go into effect, according to the article.

Forty-six states have passed laws banning e-cigarette sales to minors, and 12 states have passed laws requiring child-proof packaging for e-liquids and e-cigarettes. Attorneys general are using these laws to try to force companies to stop running ads that appeal to teens. They are also trying to require e-cigarette companies to use child-proof packaging and stronger age verification systems for their websites and online deliveries.