study concludes that thirdhand smoke is a substantial hazard that puts anyone exposed at risk of lung damage. Thirdhand smoke is exposure to tobacco smoke that off-gasses from surfaces on which it has deposited during active smoking, although the exposure occurs when smoking is not present. According to one of the study authors quoted in a KABC-TV article about the study, the results of the study showed that: "exposure to thirdhand smoke is as damaging, and in some cases, more damaging than secondhand or firsthand smoke." This was not an aberrant quotation, as a press release issued by the research institute where the authors work made the same claim. The study itself concludes that "THS [thirdhand smoke] is a hidden toxin present in the households of smokers where pregnant women and small children live without realizing that they are being exposed to such dangerous toxicants. The same risk exists for adult workers who clean and change bed sheets in hotel rooms where cigarette smoking is allowed, all over the world: a problem of global proportions!" The Rest of the Story What is the actual scientific evidence uncovered in this study of thirdhand smoke that demonstrates it is a problem of global proportions, threatening hotel workers throughout the world? The evidence is as follows: "Fetal rat lung explants were exposed to nicotine, 1-(N-methyl-N-nitrosamino)-1-(3-pyridiny\\... (NNA), or 4-(methylnitrosamino)-1-(3-pyridyl)-1-bu\\... (NNK), the two main tobacco-specific N-nitrosamine constituents of THS, for 24 h. We then determined key markers for alveolar paracrine signaling [epithelial differentiation markers surfactant