In today’s Federal Register, the U.S. Environmental Protection Agency (EPA) published a notice describing the design and format of EPA’s voluntary Nanoscale Materials Stewardship Program (NMSP) for nanoscale materials under the Toxic Substances Control Act (TSCA). EPA intends the NMSP “to complement and support its new and existing chemical efforts on nanoscale materials” under TSCA. Participants may participate in a basic program by submitting existing data, or may participate in an in-depth program to test engineered nanoscale materials. EPA intends to publish a summarized interim report approximately one year after the initiation of the NMSP, which will be based on data reported during the first six months of the basic program. EPA will then develop a more detailed report reflecting its evaluation of the NMSP approximately two years after initiation of the NMSP.