A new study in Regulatory Toxicology and Pharmacology reports on the chemical composition of e-cigarette vapor and compares those results with cigarette smoke. The authors, Drs. Rana Tayyarah and Gerald A. Long, are employed by Lorillard Tobacco Co., which would generally bar them from presenting their data in many journals or conferences, no matter how rigorous or valid the experimental technique and results might be. We here at ACSH have no such compunction. The authors used standardized machine-puffing to measure constituents of e-cig vapor; they found nicotine, propylene glycol or glycerin, water, and flavors. Aerosol nicotine was 85 percent lower than cigarette smoke. Mainstream cigarette smoke (the same stuff a smoker inhales while smoking) had about 1,500 times more harmful and potentially harmful constituents (HPHC) than e-cigarette aerosol or puffing on room air. In sum: 1. HPHCs from e-cigs was equivalent to room air; 2. no cigarette-smoke-derived HPHCs were detected in e-cig vapor; 3. these results support those who advocate for the relative safety (“reduced exposure to toxicants”) of e-cigarettes, both for vapers and for bystanders. ACSH’s Dr. Gil Ross had this comment: “I really have nothing much to add to the study’s summary and abstract. You get out what you put in, and e-cigarettes by and large have only a few chemicals, so there’s just not that much to breathe, either in or out. I am certain this study will change no minds in the hotbeds of anti-e-cig propaganda, mainly because the results do not conform to their agenda, but also because the authors work for Big Tobacco. In my opinion, this study merely confirms the results others have noted many times before.”