She said allowing the devices in places where cigarettes are now banned also could "renormalize" smoking and undermine the public perception that the habit is now acceptable only outdoors or in private.
"We don't want a step backward with that," she said.
Manufacturers say the vapor they emit is harmless, and most scientists agree that regular smokers who switch to e-cigarettes are lowering their health risk substantially. [...]
The devices, though, aren't heavily regulated. And experts say consumers can't yet be sure whether they are safe either for users or people exposed to second-hand vapor puffs.
I'd just like to point out that New York has banned something before San Francisco. Truly my city is losing its edge.