On September 22, 2010, the California Department of Toxic Substances Control (CDTSC) and the U.S. Environmental Protection Agency (EPA) held a public workshop on state and federal nanomaterial activities. During the workshop, CDTSC and EPA discussed the results of California’s data call-in (DCI) for carbon nanotubes (CNT), its plans for future DCIs, and EPA’s efforts related to CNTs. The candidate chemicals for CDTSC’s second DCI, which it intends to issue this Fall, include nanosilver, nano zero valent iron, nano titanium dioxide, nano zinc oxide, nano cerium oxide, and quantum dots. CDTSC may also include in the DCI a request for more information concerning CNTs incorporated in nanometals. According to CDTSC, the DCI will focus its initial questions on analytical test methods for the respective nanomaterial chemical, as well as its metabolites and breakdown products, in various matrices. The meeting presentations for each of the DCI candidates include more specific information regarding applications, production, human health and environmental concerns, why CDTSC is interested, and possible DCI questions.