The U.S. EPA's High Production Volume (HPV) Challenge Program is ensuring that basic health and environmental effects data on approximately 2,800 HPV chemicals is made available to the public. Since the Program's inception in 1998, industry chemical manufacturers and importers have participated in the Challenge by sponsoring over 2,200 chemicals. More than 400 companies and 100 consortia have sponsored 1,371 chemicals directly in the Program and an additional 851 chemicals have been sponsored indirectly in an international counterpart to the HPV Challenge Program, the International Council of Chemical Associations (ICCA) HPV Initiative. Three hundred . fty-three test plans have been submitted as of July 2004 for 1,266 of the 1,371 chemicals sponsored directly in the HPV Challenge Program (or 92%). EPA expects that the end of 2004 will be a critical time as sponsors work to fulfill their commitments by submitting test plans and data summaries for the remaining 8% of the sponsored chemicals, and also to submit completed data packages where additional testing was needed.