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Tox21
is a research collaboration of four U.S. federal agencies: National Institute of Environmental Health Sciences (NIEHS) Division of Translational Toxicology (DTT), National Center for Advancing Translational Sciences (NCATS), Food and Drug Administration (FDA), and Environmental Protection Agency (EPA).
Tox21 Accomplishments
The
Tox21 Consortium
continues to generate data on pharmaceuticals and environmental chemicals. These publicly-available data have been used by groups around the world to expand understanding of NAMs and
in vitro
methods, including their application and limits.
The databases also facilitate the incorporation of new data types into translational and regulatory decisions.
Resources
Tox21 Data
Tox21 data are publicly available through the National Library of Medicine’s PubChem, the EPA Chemistry Dashboard, and the NIEHS Division of Translational Toxicology’s Chemical Effects in Biological Systems Database.
Curated Tox21 Gateway
A curated collection of information on Tox21 data, assay annotations, publications, presentations, and tracking tools is available at the Tox21 Gateway.
Software and Analytical Tools
Novel software and analytical tools are developed and maintained by partners:
NIEHS
NCATS
The partnership formed in 2008 in response to concerns that traditional approaches to toxicology testing could not keep pace with a rapidly growing list of industrial and environmental chemicals, pesticides, food additives, food contaminants, and medical products. Advocates called for a new approach that transformed toxicology from an observational science that monitored the effects of chemicals to a predictive discipline that better forecasts chemical toxicity and effects on human health.
The Tox21 program has been guided by a series of important vision and planning reports.
Toxicology in the 21st Century: The Role of the National Toxicology Program (2004)
and
National Toxicology Program for the 21st Century: A Roadmap for the Future (2004)
established a foundation for the collaboration.
Toxicity Testing in the 21st Century: A Vision and a Strategy (2007)
created a three-phase program to develop and expand a library of chemical testing results.
A more recent document —
The U.S. Federal Tox21 Program: A Strategic and Operational Plan for Continued Leadership (2018)
— expanded the focus of its research activities. It challenged the partnership to develop alternative test systems that are predictive of human toxicity, address technical limitations in
in vitro
test systems, curate legacy animal (
in vivo
) toxicity testing data, establish scientific confidence in new approach methodologies (NAMs) and
in vitro
test systems, and refine alternative methods for characterizing pharmacokinetics and disposition in
in vitro
assays.
For more about the history of Tox21, see
about Tox21
Goals of the Tox21 Program
Contribute to the reduction, refinement, and replacement (3Rs) of animal use in toxicity testing and support development of NAMs.
Develop more relevant and
predictive models
of
in vivo
toxicological responses.
Identify mechanisms of chemically induced biological activity.
Prioritize chemicals for more extensive testing.
Reduce time, effort, and costs associated with toxicology testing.
Tox21 Consortium Fact Sheet
The
Tox21 Fact Sheet
offers a summary of the program, highlights key successes and translational applications, and presents an overview of the consortium’s strategic direction as the science continues to evolve.
Related Links
The US Federal Tox21 Program: A Strategic and Operational Plan for Continued Leadership, (2018)
Toxicity Testing in the 21st Century: A Vision and a Strategy (2007)
National Toxicology Program for the 21st Century: A Roadmap for the Future (2004)
Toxicology in the 21st Century: The Role of the National Toxicology Program (2004)
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Last Reviewed: January 06, 2026