Ban on e-cigarette in public places where tobacco smoking is prohibited, in Los Angeles following a vote on Thursday, including work places, restaurants and bars.
The LA City Council voted by 14-0 to outlaw their use in indoor workplaces, outdoor dining areas, parks, recreational areas, beaches, bars and nightclubs where lighting up is banned.
So called "vaping" lounges and stores will be exempted, in line with exceptions made for cigar and hookah lounges where tobacco smoking is allowed, as will using e-cigarettes for "theatrical purposes."
The battery-powered devices, marketed as aids to quit smoking, allow users to inhale a nicotine-laced vapor, but experts say not enough is known about the effect of the chemicals involved, on smokers or those around them.
"Safer does not mean safe," said the LA County's public health director Dr. Jonathan Fielding. "Although they are less harmful than traditional cigarettes, some e-cigarettes contains some health risks."
He added that e-cigarettes have grown into a "$1.5 billion industry that has caught the attention of big tobacco which historically has had scant regard for public health."
The LA vote follows a similar move last December in New York City, which agreed to extend its strict smoking ban to e-cigarettes, barring them from bars, restaurants, parks, beaches and other public places.
The industry has exploded in the United States, doubling turnover in one year to $1-1.7 billion at the end of last year, according to financial group Wells Fargo last year. Sales grew ninefold between 2010 and 2012, studies suggest.
Regulation varies from state to state in the US, but they are often banned from sale to minors, and they are not allowed on planes or trains.
In Europe several countries -- including Belgium, Luxembourg, Malta, Slovenia and Lithuania -- e-cigarettes are banned wherever tobacco smoking is banned. Some states, including Italy and France, outlaw sales to minors.
E-cigarettes are banned in several Latin American countries, while in Asia there is relatively little interest in countries where tobacco is cheap including China, where the devices were invented.