San Francisco has become the first major US city to ban the sale of electronic cigarettes after officials gave the measure its second and final vote.
Supporters said they hope the legislation will curb under-age use of e-cigarettes, but critics say the ban will make it harder for adults to purchase an alternative to regular cigarettes.
San Francisco is a city that celebrates its marijuana culture but appears deeply opposed to other vices.
Voters last year approved a ban on the sale of flavoured tobacco, and in 2016 a tax on sugar-sweetened drinks.
E-cigarette maker Juul Labs, based in San Francisco, said it is opposed to youth vaping.
The company is working on a ballot initiative that would regulate but not ban e-cigarette sales.