Are e-cigarettes any safer? According to a study in the peer-reviewed journal Nicotine and Tobacco Research it might not be the case. Some tank-style e-cigarettes emit cancer-causing formaldehyde in their vapor at levels similar to traditional tobacco cigarettes.

The problem appears to happen at some tank-style e-cigarettes when they get so hot, causing formaldehyde to form in the vapor they put out.

Dr. Alan Shihadeh at the Virginia Commonwealth University's Center for the Study of Tobacco Products, who led one of the studies, acknowledged that while the e-cig study only examined a handful of carcinogens, traditional cigarettes put out dozens of cancer-causing compounds. He told The New York Times:
If I was in a torture chamber and you said I had to puff on something, I'd choose an e-cigarette over a regular cigarette. But if you said I could choose an e-cigarette or clean air, I'd definitely choose clean air. And I definitely wouldn't drip.