The U.S. Food and Drug Administration (FDA) has published its methodology for risk-ranking and prioritizing chemicals in the food supply for systematic post-market safety reevaluation.

The new Expanded Decision Tree (EDT) chemical toxicity and risk screening tool provides a consistent, systematic, and science-based approach to support evaluation of the safety of chemicals in food based on their structure and estimated toxicity. The EDT was submitted for external peer-review in March 2024, and was revised based on input received. It is now available to the scientific community for technical consideration.  

FDA is developing an automated software solution for the EDT for general public use, and will further refine the EDT over time with access to more information about chemicals in the food supply and based on public input.  

In the near future, FDA will release an informational video to explain the EDT and will hold listening sessions to receive input from interested parties.

The EDT is a modernized version of the original Cramer Decision Tree tool and can be used to screen chemicals based on their structural features. The Cramer Decision Tree tool, which is a scientific tool that sorts chemicals into classes of chronic toxic potential using a series of mainly chemical structure-based questions, has been widely used by scientists to provide a quick, preliminary estimate of a new chemical’s predicted toxicity, especially when the testing data about a chemical is limited. The updated, expanded, and refined set of fully chemical structure-based questions in FDA’s EDT allows classification of chemicals with greater specificity than the Cramer Decision Tree.

The EDT database contains toxicity studies, metabolism data, and chemical data for a diverse set of chemicals present in food. It draws from literature and reports published by global authorities and international regulatory bodies such as the Joint Food and Agriculture Organization of the United Nations (FAO)/World Health Organization (WHO) Expert Committee on Food Additives (JECFA), the Joint FAO/WHO Meeting on Pesticide Residues, the U.S. Environmental Protection Agency (EPA), the California Environmental Protection Agency (CalEPA), the European Chemicals Agency (ECHA), and the European Food Safety Authority (EFSA).

Ultimately, FDA intends to use the EDT in both pre- and post-market evaluation of chemicals in food to help ensure the safety of the food supply. Once fully operational and automated, it will help to enable fast screenings of chemicals, identify data gaps in information about chemicals, support the agency’s assessment of chemicals submitted through premarket programs, screen and prioritize chemicals for further evaluation through the post-market assessment program, and inform assessments of cumulative toxicity and mixtures of chemicals. FDA is still considering all of the potential applications of the EDT tool for the agency’s various regulatory responsibilities, but FDA is already piloting use of the EDT to inform its pre- and post-market programs.

Currently, using the EDT to screen a chemical is a manual process that requires organic chemistry and metabolism expertise to evaluate a chemical efficiently and reproducibly. Automation of the EDT is necessary to fully realize its capabilities and for the tool to be more broadly used. FDA is working to develop an automated version of the EDT.

The release of the EDT is in line with the plans outlined by FDA during the previous administration for the development of a systematic post-market review process for chemicals in food.

Learn more about the EDT on FDA's website.