A high-speed robotic screening system, aimed at protecting human health by improving how chemicals are tested in the United States, has begun testing 10,000 compounds for potential toxicity. The compounds cover a wide variety of classifications, and include consumer products, food additives, chemicals found in industrial processes, and human and veterinary drugs. (A complete list of the compounds is  available at www.epa.gov/ncct/dsstox.)

The testing represents 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).

“There has never been a compound library like this before,” said NIEHS/NTP Director Linda Birnbaum, Ph.D.

Birnbaum said some of the compounds being tested are mixtures of chemicals. “All of us are exposed to many different chemicals at the same time, not just one chemical at a time,” she said. “These new technologies allow us to more rapidly advance our understanding of not only individual chemicals, but mixtures of chemicals as well.”

A subset of the NTP portion of the  library will focus on pilot testing several formulations or mixtures of compounds, a priority area for NIEHS/NTP. The library constituents were selected after a thorough analysis of existing scientific studies, more than 200 public chemical databases, and chemical nominations received from internal and external partners. Each test compound will undergo a thorough chemical analysis to verify its identity and determine its purity, concentration, and stability.

The goal of the testing is to provide results that will be useful for evaluating if these chemicals have the potential to disrupt processes in the human body to an extent that leads to adverse health effects.

The development of methods for evaluating chemical toxicity has the potential to revolutionize the assessment of new environmental chemicals and the development of new drugs for therapeutic use.  

The EPA seeks to understand the molecular basis of such chemicals to better protect human health and that of the environment.

All testing results will be available to the public through NIH and EPA chemical toxicity databases. In addition, NCTT has created a Tox21 chemical inventory browser available at tripod.nih.gov/tox21chem to provide researchers with additional about the chemicals. For more information about Tox21, visit www.niehs.nih.gov/health/assets/docs_p_z/ntp-tox21.pdf.