Gennaro, the lead sponsor of the bill banning public use of e-cigarettes now before the council, said he wanted to "err on the side of caution." He added that the city's measures to ban smoking from outdoor public areas under Mayor Michael Bloomberg were more about public acceptance of smoking than science.
"Those second set of measures were more about sociology and denormalizing than they were hard medical science," Gennaro said on "Squawk on the Street." "We thought it was important to make sure smoking was completely denormalized."
In the meantime, electronic cigarettes make up a booming business that could surpass $1.7 billion this year, analyst Bonnie Herzog of Wells Fargo Securities told CNBC in August. The surge in popularity also comes amid cries for more regulation, at both the federal and local levels.
—By CNBC's Jeff Morganteen. Follow him on Twitter at @jmorganteen and get the latest stories from "Squawk on the Street." CNBC's Dan Mangan contributed to this report.