California lawmakers are debating whether to include e-cigarettes in bans on smoking in public places, the Los Angeles Times reports.

The state has outlawed cigarette smoking in most public places. The California Senate recently approved a bill that would ban e-cigarettes from every place smoking is already banned. The state Assembly has not yet taken up the measure.

E-cigarettes are designed to deliver nicotine in the form of a vapor, which is inhaled by the user. They usually have a rechargeable, battery-operated heating element, a replaceable cartridge with nicotine or other chemicals and a device called an atomizer that converts the contents of the cartridge into a vapor when heated. E-cigarettes often are made to look like regular cigarettes.

People who use e-cigarettes object to prohibitions on the devices in public spaces, arguing they don’t emit smoke. They inhale and exhale vapor that contains flavored liquid nicotine. Proponents of the ban on using e-cigarettes in public say the effects of the devices and their vapor are still untested and unknown.

Dr. Michael Siegel of the Boston University School of Public Health told the newspaper that no studies so far have shown that e-cigarettes release large amounts of dangerous chemicals in the air. “Unlike tobacco smoke, the vapor dissipates very quickly,” he said. “It looks like it’s probably very minor risk.”

A recent study suggests e-cigarettes may help some smokers quit. The study of smokers with no desire to quit found up to 13 percent were not smoking regular cigarettes after one year of using the electronic devices. More than half of the study’s participants reduced their tobacco use soon after they starting using e-cigarettes.