ACToR: Aggregated Computational Toxicology Resource"ACToR, a free database from the National Center for Computational Toxicology of the Environmental Protection Agency, compiles quantitative and qualitative information on pesticides, industrial chemicals, water contaminants, and other potentially toxic compounds from a growing list of more than 200 Data Collections from state, federal, and international agencies, academic institutions, and commercial sources. The home page displays a brief description and a search box for chemical name or CAS registry number.