New study comes the closest yet to proving that e cigarettes aren't as dangerous as smoking E Cigarette Smoking May Release Formaldehyde, Other Carcinogens AboutLawsuits.com Vapes don't produce harmless water vapor. They can contain addictive nicotine, cancer causing chemicals like acetaldehyde and formaldehyde, and heavy metals that don't belong in your body. Live Vape Free is a text Some e cigarettes deliver a puff of carcinogens