A recent article, “Debunking Some Misconceptions about Nanotoxicology”, in the journal Nano Letters, written by David B. Warheit from the DuPont Haskell Global Centers for Health and Environmental Sciences, addresses what the author perceives to be myths and misconceptions regarding nanotoxicology. Nanotoxicology studies are growing, and a general understanding of nanotoxicity is expanding, yet the lack of a common standard system makes these studies difficult to compare, and some even seem to contradict each other. According to Warheit, “perhaps the most important point to be made is that nanoparticle toxicological effects are complex and involve a variety of factors including physicochemical characteristics, particle-cellular interactions, routes and degrees of exposure, biokinetics, logistics, and other considerations. Unfortunately, these effects cannot yet be accurately modeled using simple systems.” His perceived myths are the following: “Myth 1: Nanoparticles are always more toxic than bulk particles of similar or identical composition; Myth 2: Particle size and surface area are the critical indices that influence nanoparticle toxicity; Myth 3: All forms of nanotitanium dioxide particles have similar toxicity profiles – or nano TiO2 is nano TiO2 – i.e., we can identify nanoparticle types by their ‘core identities’ without specifying their compositional physicochemical characteristics; Myth 4: No current methodologies are available for the responsible development of nanoscale materials; and, Myth 5: Pulmonary hazard assessments for nanoparticles can be accurately evaluated using in vitro or in silico methodologies.” Warheit concludes that, because hazard effects cannot yet be accurately modeled and the database of hazards for nanomaterials is so limited, it will be important to “…rigorously characterize the material of interest and generate substantive hazard data that is accurate and can be confirmed independently by other research investigators.”