The town of Lemon Grove, California, has banned e-cigarettes in bars and restaurants and in public areas like parks, effective October 1st. If that seems a lot like cigarette rules, that is what they intended.
Critics argue conflating the two makes no sense. They both contain nicotine, but so do gums and patches. None of them contain tobacco smoke, which does have hundreds of dangerous chemicals and has been shown to be a risk factor for numerous diseases for over 50 years.
If the rationale is smoke, banning e-cigarettes is not evidence-based but the U.S. Food and Drug Administration has instead argued both that they have jurisdiction to regulate nicotine replacement therapies, such as gums and patches containing nicotine (the argument vaping proponents use is that they are smoking cessation or harm reduction, like gums and patches) and less convincingly that the vaping devices should be considered a tobacco product (which covers chewing tobacco, etc.) and therefore under their jurisdiction regarding safety and composition. The vaping community disagrees but there is as of yet no mechanism to insure the quality and safety of the ingredients. The American Council on Science and Health, while advocating for all harm reduction and smoking cessation techniques to get rid of cigarette smoking, has cautioned about the presence of aldehydes but otherwise concurs that they carry no health risk. Studies have shown they are likely as effective as other smoking cessation techniques.