The European Commission’s (EC) Scientific Committee on Consumer Products (SCCP) released on March 3, 2008, a document entitled Opinion on Safety of Nanomaterials in Cosmetic Products (Opinion). In its Opinion, the SCCP divides nanoparticles into two groups: 1) soluble and/or biodegradable nanoparticles; and 2) insoluble particles. The SCCP states that, for the soluble and/or biodegradable group, “conventional risk assessment methodologies based on mass metrics may be adequate, whereas for the insoluble particles other metrics, such as the number of particles, and their surface area as well as their distribution are also required.” According to the SCCP, when assessing possible risks associated with nanoparticles, it is crucial to consider their uptake, and that it is primarily for the insoluble particles that health concerns related to possible uptake may arise. The SCCP concludes that, at present, there is inadequate information on: hazard identification; exposure assessment; uptake; the role of physico-chemical parameters of nanoparticles determining absorption and transport across membranes in the gut and lungs; the role of physico-chemical parameters of nanoparticles in systemic circulation determining biokinetics and accumulation in secondary target organs; possible health effects; and translocation of nanoparticles via the placenta to the fetus. The Opinion states that review of the safety of the insoluble nanomaterials presently used in sunscreens is required.