From mascara to tennis balls to baby wipes, tiny nanomaterials are hidden in many of the products we use every day. Although there is much more we’d like to know about how exposure to nanomaterials affects human health and the environment, preliminary studies demonstrate that some nanomaterials are likely to be harmful. The current approach to chemical regulation cannot be relied upon to prevent harm from nanomaterials; it is slow, costly, and fails to prevent exposures to known hazardous chemical pollutants. It is crucial that government regulation and public debate catch up with this rapidly advancing technology.