SAN FRANCISCO — San Francisco became the first major US city to ban the sale of electronic cigarettes after supervisors gave the measure its second and final vote Tuesday.

Backers say they hope the legislation will curb underage 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 it appears deeply opposed to other vices. Last year, voters approved a ban on the sale of flavored tobacco and in 2016, a tax on sugar-sweetened drinks.

E-cigarette maker Juul Labs, which is based in San Francisco, says it is opposed to youth vaping.

The company is working on a ballot initiative that would regulate but not ban e-cigarette sales.