Food and Drug Administration says five electronic cigarette companies are violating federal laws by making unsubstantiated claims about the product and for poor manufacturing practices.
The FDA said Thursday it sent warning letters to the companies, saying that the e-cigarettes are subject to federal regulation as drugs. That means the companies can’t claim their products can help people quit smoking cigarettes unless they has been proven safe and effective.

A letter also was sent to the Electronic Cigarette Association saying the warnings were not meant to be seen as a larger effort to ban e-cigs.

E-cigarettes are plastic and metal devices that heat a liquid nicotine solution in a disposable cartridge, creating vapor that users inhale.