Description This dataset contains ecotoxicity data of 1585 chemicals of environmental concern (CECs) and chemical identifiers. The ecotoxicity data was retrieved from US EPA ECOTOX Knowlegdebase in ASCII file format and was aggregated for the ecotoxicity groups algae, crustaceans, and fish based on the ideas of Busch et al. 2016. The dataset includes the 5-percentile, the mean and the geomean of all retrieved ecotoxicity for each compound. Missing ecotoxicity data was estimated with ECOSAR 1.0 algorithms for green algae, daphnids, and fish using ChemProp 6.8. The main purpose of this dataset is the toxic unit (TU) based hazard assessment of environmental water samples. Chemical properties were estimated using OPERA 2.7, Instant JChem, and ACD Percepta 2015 based on QSAR-ready SMILES derived from OPERA 2.7. All data aggregated from EcoTox Knowledgebase (e.g., raw values, species, etc.) is available in the dataset in the detailed sheets. REcoTox, the processing script written in R is available on GitHub. CAUTION It needs to be emphasized that quantitative-structure activity relationship data is just an estimate, which does not necessarily reflect the real property and behaviour of a modelled compound. The calculated data needs to be reviewed in deep. Especially for non-polar or very polar compounds, the QSAR predictions might fail. If a compound ranks high in the TU ranking, it is required to search for literature or regulative data evidences to underpin the finding to avoid false positive prioritizations. RELEASE NOTE Version 210714_v1 was created with REcoTox version v0.1.0.