NICEATM has released the Collaborative Acute Toxicity Modeling Suite (CATMoS), a free resource for screening organic chemicals for acute oral toxicity. CATMoS is implemented in v2.0 of the Open Structure-Activity/Property Relationship App (OPERA), a free and open-source quantitative structure-activity relationship (QSAR) tool. OPERA v2.0 can be downloaded from the NIEHS Github repository at
CATMoS is the result of a global collaboration to develop in silico models to predict acute oral toxicity. It is a suite of consensus models developed by combining the results of individual models contributed by participants in the April 2018 Workshop on Predictive Models for Acute Oral Systemic Toxicity (see and The individual models were built using information on chemical structures and rat oral acute toxicity data for nearly 9000 chemicals, and tested using approximately 3000 chemicals.
CATMoS includes models for predicting five acute oral toxicity endpoints: very toxic, non-toxic, U.S. Environmental Protection Agency hazard classification, United Nations Globally Harmonized System of Classification and Labelling of Chemical (GHS) hazard classification, and LD50. Predictions generated by CATMoS may be useful to those developing or triaging new chemicals or for prioritizing existing chemicals for more detailed and rigorous toxicity assessments.