US health authorities are alarmed by the rise in popularity of e-cigarettes.

San Francisco on Tuesday became the first major US city to effectively ban the sale and manufacture of electronic cigarettes.

The city's legislature unanimously approved an ordinance which backers said was necessary due to the "significant public health consequences" of a "dramatic surge" in vaping among youths.

The ordinance says e-cigarette products sold in shops or online in San Francisco would need approval by federal health authorities, which none currently has.

US health authorities are alarmed by the rise in popularity of e-cigarettes, battery-powered devices which enable users to inhale nicotine liquids that are often fruit flavored.

The number of young Americans using e-cigarettes grew by 1.5 million in 2018, with about 3.6 million middle and high school students using vaping products.

San Francisco is home to market-leading e-cigarette maker Juul.

The city's mayor London Breed has 10 days to sign the legislation, which she has said she will do.

"We need to take action to protect the health of San Francisco's youth and prevent the next generation of San Franciscans from becoming addicted to these products," Breed said in a statement Tuesday ahead of the vote.

She added that e-cigarette companies were "targeting our kids in their advertising and getting them hooked on addictive nicotine products."

But critics say the legislation will make it harder for people seeking alternatives to regular cigarettes. E-cigarettes do not contain the cancer-causing products found in tobacco.

An editorial in the Los Angeles Times noted that regular cigarettes were still for sale in San Francisco, arguing that "it's bad public health policy to come down harder on the lesser of two tobacco evils."

Juul said in a statement Monday that a ban would "not effectively address underage use and will leave cigarettes on shelves as the only choice for adult smokers."

Concern is growing about the potential health consequences of vaping, which remain largely unknown in part because the practice is so new.

Experts point out that it took decades to determine that smoking tobacco -- which accounts for more than seven million premature deaths worldwide every year -- is truly dangerous.

Beside the well-known addictive consequences of consuming nicotine, public health experts are focusing on the effect of heating the liquid nicotine cartridges to high temperatures.

The San Francisco ordinance text said that nicotine exposure during adolescence "can harm the developing brain" and "can also increase risk for future addiction to other drugs."

Unlike an e-cigarette ban in force in Singapore, the San Francisco legislation does not restrict the use of vaping products.

Recreational cannabis use has been legal in California for people over the age of 21 since January 1, 2018.