AKIPRESS.COM - San Francisco has become the first US city to ban e-cigarette sales until their health effects are clearer, BBC reports.

Officials on Tuesday voted to ban stores selling the vaporisers and made it illegal for online retailers to deliver to addresses in the city.

The California city is home to Juul Labs, the most popular e-cigarette producer in the US.

Juul said the move would drive smokers back to cigarettes and "create a thriving black market".

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.

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.

Earlier this year the US Food and Drug Administration (FDA), 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.