San Francisco has become the first US city to ban e-cigarette sales until their health effects are clearer.
Officials on Tuesday voted to ban stores selling the vaporisers and made it illegal for online retailers to deliver to addresses in the city.
San Francisco is home to Juul Labs, the most popular e-cigarette producer in the US.
Firms are accused of targeting young people, but Juul says e-cigarettes help people switch from regular tobacco.
San Francisco’s mayor, London Breed, has 10 days to sign off the legislation, but has indicated that she would. The law would begin to be enforced seven months from that date, although there have been reports firms could mount a legal challenge.
Earlier this year the US Food and Drug Administration, the national regulator, issued proposed guidelines giving companies until 2021 to apply to have their e-cigarette products evaluated.
A deadline had initially been set for August 2018, but the agency later said that more preparation time was needed.
Anti-vaping activists say firms deliberately target young people by offering flavoured products. Critics say that not only is more scientific investigation into the health impact needed, vaping can encourage young people to switch to cigarettes.
The firms, however, say their products can help people give up regular tobacco.
According to the US Centers for Disease Control and Prevention, the number of US teenagers who admitted using nicotine products rose about 36% last year, something it attributed to a growth in e-cigarette use.
Under federal law, the minimum age to buy tobacco products is 18 years, although in California and several other states it is 21.
Juul previously said it supported cutting vaping among young people but only in conjunction with tougher measures to stop them accessing regular cigarettes.
The company’s small device, just longer than a flash drive, has about 70% of the US vaping market.
The firm said in a statement several weeks ago: “This proposed legislation begs the question – why would the city be comfortable with combustible cigarettes being on shelves when we know they kill more than 480,000 Americans per year?”
Juul had yet to comment on Tuesday’s decision.
San Francisco becomes first US city to ban e-cigarettes