ST. PAUL — An attempt to treat electronic cigarettes like regular smokes and curb their use in public stalled Tuesday in the Minnesota Legislature, ending the closely watched debate for the year.

A House-Senate conference committee decided against adding e-cigarette use to the indoor air laws that would have prohibited their use in most public spaces. Lawmakers are tackling how to regulate the emerging devices that deliver nicotine and emit vapor.

Lawmakers are ready to restrict e-cigarette sales to prevent minors from accessing them and to bar their use on school grounds and in nursing homes, day cares and government-owned buildings. But the broader indoor air measure that cleared the Senate was set aside. House members said they lacked enough votes to approve what would have been some of the nation’s strictest regulations.

“It’s not easy to be the first. It’s not easy to be trailblazing,” said Democratic Rep. Laurie Halverson, a proponent of curbing e-cigarette use in public.

The health policy bill with the e-cigarette language also contains measures dealing with

pharmacies and banning tanning bed use by minors. Rep. Tina Liebling, DFL-Rochester, said she feared the full package would have been imperiled if the broader “vaping” restrictions were in it.

Cap O’Rourke, who represents dozens of e-cigarette sellers for the Independent Vapor Retailers of Minnesota, said lawmakers were wise to wait.

“We’re happy that businesses can continue to make their own decisions and we can wait until the science can show us definitive proof of their health effects,” O’Rourke said.

The rules lawmakers are primed to pass would also require the e-cigarette liquids to be sold in tamper-proof bottles that make it hard for young children to open. The devices and related supplies couldn’t be sold at moveable kiosks in malls.

But a coalition of anti-smoking groups fought aggressively to outlaw their use in bars, restaurants and other venues. They contend that the vapors could have second-hand risks, although scientific evidence is in short supply.

State Sen. Kathy Sheran, DFL-Mankato, was disappointed that the indoor air measure failed.

“We almost got to the goal line, but we didn’t score in terms of protecting the general public from unknown exhaled chemicals of e-cigarettes,” she said.

Sheran and O’Rourke predicted an even louder debate next year as both sides organize. Case in point: the e-cigarette retailers are planning to form a political fund to engage in the fall campaign.