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The most effective way to achieve long-term environmental results is through the use of a consistent set of metrics and decision making framework. EPA has developed TRACI, the Tool for the Reduction and Assessment of Chemical and other environmental Impacts, to assist in impact assessment for Sustainability Metrics, Life Cycle Assessment, Industrial Ecology, Process Design, and Pollution Prevention.

To develop TRACI, impact categories were selected, available methodologies were reviewed, and categories were prioritized for further research. During the impact assessment methodology research phase, consistency with previous modeling assumptions (especially of EPA) was important for every category. The human health cancer and non-cancer categories were heavily based on the assumptions made for EPA Risk Assessment Guidance for Superfund and EPA's Exposure Factors Handbook. For categories such as acidification and smog formation, detailed U.S. empirical models, such as those developed by the U.S. National Acid Precipitation Assessment Program and the California Air Resources Board, allowed the inclusion of the more sophisticated location specific approaches and location specific characterization factors. When there was no EPA precedent, assumptions and value choices were minimized by the use of midpoints. See the following figure for a graphical representation of TRACI with human health cancer as the example impact category.

TRACI figure Please contact Jane Bare at 513-569-7513 for detailed description

Methodologies were developed specifically for the United States using input parameters consistent with U.S. locations for the following impact categories: acidification, smog formation, eutrophication, human cancer, human non-cancer, and human criteria effects. Probabilistic analyses allowed the determination of an appropriate level of sophistication and spatial resolution necessary for impact modeling for several categories, yet the tool was designed to accommodate current inconsistencies in practice (e.g., site-specific information is often not available).

TRACI's modular design allows the compilation of the most sophisticated impact assessment methodologies that can be used in software developed for PCs. Where sophisticated and applicable methodologies didn't exist, research was conducted by the use of various simulations to determine the most appropriate characterization factors to represent the various conditions in the United States. As the research, modeling, and databases for LCIA methods continue to improve, each module of TRACI can be improved and updated. Future research is expected to advance methods for resource-related impact categories.

The following two papers provide a description of TRACI in varying levels of detail:

The AICHE 2002 paper provides a brief description of the methodologies underlying TRACI, along with a discussion of the application of TRACI methodologies in various decision-making frameworks.

The Journal of Industrial Ecology paper provides additional detail about the impact assessment methodologies within TRACI.

If you would like additional information concerning use of TRACI or incorporation of TRACI into other environmental tools, please contact Jane Bare.


Use of TRACI, including but not limited to the impact assessment modeling, does not confer legal rights or impose legal obligations upon any member of the public. Furthermore, it does not release users from any potential liability, either administrative or judicial for any damage to human health or the environment.

Neither EPA nor anyone involved in the development of TRACI makes any warranty, expressed or implied, as to any matter whatsoever, including the accuracy of the database, the appropriateness of actions taken by third parties as a result of using the model, or the merchantability or fitness of the model for a particular purpose. EPA does not endorse any products or services.

Principal Investigator

Jane Bare
Office of Research and Development
National Risk Management Research Laboratory
Sustainable Technology Division
Systems Analysis Branch
26 West Martin Luther King Drive (MS-466)
Cincinnati, Ohio 45268


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