This letter was co-authored by Dr. Michael Siegel of the Boston University School of Public Health and Dr. Konstantinos Farsalinos of the Onassis Cardiac Surgery Center in Athens, Greece.

The data presented by Jensen et al. (Jan. 22 issue) in their recent letter to the editor do not support their conclusion that e-cigarette use presents a likely risk of excessive exposure to formaldehyde. The 5-V puff topography used by Jensen et al. appears to have overheated the coil, resulting in excessive breakdown of propylene glycol to formaldehyde. This phenomenon is readily detected by the consumer by virtue of an exceedingly unpleasant burning taste, commonly referred to as a “dry puff.” It has been described in detail in the literature. The consumer can address this issue by discontinuing use of the unit or reducing puff duration while increasing the interval between puffs. Thus, taste prevents e-cigarette users from exposing themselves to excessive formaldehyde from overheating of the coil.