This article introduces this special issue of Carbon devoted to the toxicology of new carbon nanomaterials. This lead article draws from the ten contributed articles to discuss overall status, trends, and research needs in this new field. Common themes in the contributed articles are highlighted and a special appeal is made for collaboration between toxicologists and materials scientists in the joint development of "green" nanomaterial formulations -those co-optimized for function and minimal health impact. (c) 2006 Elsevier Ltd. All rights reserved.