Widely cited paper claiming e-cigs not toxic also concludes cigarettes do not pose "significant risk" is just not credible

E-cigarette supporters are fond of quoting a risk assessment, "Comparison of the effects of e-cigarette vapor and cigarette smoke on indoor air quality," by McAultey et al (Inhalation Toxicology 2012; 24(12): 850-857) as evidence that e-cigarettes are safe.  Indeed, the last sentence of the abstract states, "This study indicates no apparent risk to human health from e-cigarette emissions based on the compounds analyzed."

I've gone back and re-read the paper again together with the online supplemental material and found lots of problems, including the fact that they did not detect any benzo(a)pyrene in the conventional cigarette smoke despite the fact that it has been established for over half a century that benzo(a)pyrene is an important carcinogen in cigarette smoke and that they way they did their "risk assessment" is not described in any detail.

The most amazing conclusion in the paper (on page 855, second column, 11 lines from the top), however, is that “neither vapor from e-liquids or cigarette smoke  analytes posed a condition of ‘Significant Risk’ of harm to human health via the inhalation route of exposure."

One would have thought that when the authors' analysis found that conventional cigarettes did not pose significant risk, they would have paused and recognized that there was something fatally wrong with heir data, analysis or both.

But they didn't.

I don't see how anyone can take this paper's conclusions about e-cigarette toxicity as credible when it at the same time concludes that cigarettes are not dangerous to inhale.