A high-speed robotic screening system, aimed at protecting human health by improving how chemicals are tested in the United States, begins today to test 10,000 compounds for potential toxicity. Testing this 10,000 compound library begins a new phase of an ongoing collaboration between the National Institutes of Health, the U.S. Environmental Protection Agency, and the U.S. Food and Drug Administration, referred to as Tox21. NIH partners include the National Toxicology Program (NTP), administered by the National Institute of Environmental Health Sciences (NIEHS), and the NIH Chemical Genomics Center (NCGC), part of the NIH Center for Translational Therapeutics (NCTT), housed at the National Human Genome Research Institute (NHGRI).