A new research letter in the New England Journal of Medicine examined the aerosol produced by a tank system electronic cigarette. The aerosol was collected and analyzed for formaldehyde. Two voltage settings were used: low (3.3V) and high (5.0V).
The main findings were that at low voltage, no formaldehyde was detected, but at high voltage, "high" levels of formaldehyde were detected.
Using these levels, the authors from Portland State University in Oregon extrapolate an overall lifetime cancer risk from vaping, which they claim is higher than that from cigarette smoking.
But the conditions used to study the e-cigarette aerosol at the high voltage setting were unrealistic and under such conditions, a person would never be able to use the product. The wattage being used was so high that the vaporizer was overheated (for a conventional e-cigarette it would likely damage or burn the coils), creating what is called a "dry puff phenomenon" and a taste users could not tolerate.
What this study really demonstrates is that if you overheat a vaping system, it will produce high levels of "formaldehyde releasing compounds", not formaldehyde. And to do so would require that the product essentially be unusable. It can truly only happen if someone is trying to make it happen. Biologically, as scary as it sounds (embalming fluid) formaldehyde is actually a very weak carcinogen, with only a slightly increased chance of cancer among even highly-exposed workers over an entire lifetime. The presence of one such minor carcinogen in e-cigarette vapor cannot be compared to the toxic stew of carcinogens and other toxins in cigarette smoke.
Dr. Konstantinos Farsalinos of the Onassis Cardiac Surgery Center, Athens, Greece, commented:
Thus, it is more than obvious that once again the atomizer was overheated, which of course will result in very high levels of formaldehyde production. What the authors ignore is that these conditions, commonly called dry-puff phenomenon, [are] easily detected by vapers [e-cigarette users]. In fact, overheating results in an unpleasant taste that none can withstand. As a result, no vaper is ever using the e-cigarette at such conditions and, thus, will never be exposed to such levels of formaldehyde.