The proper selection of building materials, furnishings, fixtures, and consumer and commercial products to be used indoors is critical to achieving good indoor air quality. At present, however, little information is available to help in the selection of the best products. The Indoor Air Source Characterization Project will score and rank classes of products used indoors, based on their potential as sources of indoor air exposures and risks. Selected product classes will undergo a more detailed evaluation for emissions, exposures, and risks. If warranted, industry and other interested parties may be contacted to conduct further analyses or to discuss options for reducing exposures or risks. Actions taken may be voluntary or regulatory, as appropriate. They may include changes in product manufacture or formulation, and the development and distribution of information on product content and proper methods of application or use.