Following up on a National Research Council study conducted in the late 1980s that revealed a lack of health-screening tests for high production volume (HPV) chemicals, Environmental Defense published "Toxic Ignorance" in 1997 to document the continuing absence of screening tests for the health effects of 71% of the 3,000 HPV chemicals in the U.S. economy -- and to call on the leading U.S. chemical companies to complete preliminary health screenings on their top-selling chemicals -- and to publicly disclose the results -- before the year 2000.