This article has been updated to reflect final passage by the Board of Supervisors on June 25.

San Francisco city officials voted unanimously on Tuesday to suspend the sale and delivery of electronic cigarettes until the products are approved by the Food and Drug Administration. The legislation, which still requires the mayor’s signature, would go into effect in seven months—giving e-cigarette makers until early next year to win approval from the FDA.

The measure is intended to help stem the explosive popularity of e-cigarettes among young people, which the US Surgeon General has described as an epidemic. But it’s not clear that making e-cigarettes illegal will stop teenagers from vaping.

“We’ll see if it changes behavior,” says Bonnie Halpern-Felsher, a professor at Stanford who studies how e-cigarettes affect young people. “We don’t know yet.” Halpern-Felsher welcomes the ban, but says it’s just one step toward addressing the problem. She points out that the proposal is largely aimed at the makers of e-cigarettes themselves, and “in a lot of ways this is a message to the FDA.”

The message is hurry up. Dennis Herrera, San Francisco's city attorney and coauthor of the bill, says the city wants to protect young people. But he also says he hopes the legislation will “spur the FDA to do what’s required under the law” and review whether these products are safe for consumers, and whether e-cigarettes are really the lower-risk tobacco option they claim to be.

More than one in five middle and high school teenagers vape, according to the US Centers for Disease Control. In 2018, the FDA warned e-cigarette companies to stop marketing to children and proposed restricting the sale of flavored vaping products to minors. Still, the administration has yet to review the safety of these products. In an email, FDA spokesperson Michael Felberbaum wrote: “The FDA is committed to continuing to tackle the troubling epidemic of e-cigarette use among kids. This includes limiting youth access to, and appeal of, flavored tobacco products like e-cigarettes and cigars, taking action against manufacturers and retailers who illegally market or sell these products to minors, and educating youth about the dangers of e-cigarettes and other tobacco products.”

San Francisco officials say that isn’t enough. “The epidemic is real. It needed attention,” says Herrera, “We felt it was necessary to step in and make sure we were protecting young people on our streets.” Herrera criticized the FDA for being too slow and not properly vetting e-cigarettes before they arrived on the market in 2007. He says that by failing to test the safety of the devices, the federal government “abdicated” its responsibility. So San Francisco had to step in.

The Tobacco Control Act gives the FDA authority to assess the safety and health risks of products, like e-cigarettes, that advertise themselves as low risk or less harmful than regular cigarettes. Typically the FDA is supposed to conduct these reviews before the products show up on shelves, but the agency has been slow to catch up with the vaping craze. The FDA does currently require e-cigarette manufacturers to submit applications for review, but many products like Juul didn’t get pre-market approval before they put their e-cigarettes out. Instead of removing those products, the FDA gave Juul and other companies a 2022 deadline for submitting applications for approval.

For San Francisco officials and others, that’s unacceptable. E-cigarettes may not cause lung cancer, but they do contain nicotine, which is highly addictive, and can affect adolescent brain development. Recent studies suggest they may be linked to other cardiovascular and lung conditions. The CDC does not recommend any e-cigarette products for children or teenagers, but it has said e-cigarettes have the “potential to benefit” adult smokers who switch from combustible cigarettes to e-cigarettes.