This dataset contains the different measurement data that were obtained during and in the wake of the anomalous selenium-75 (Se-75) emission from the Belgian Reactor 2 (BR2) in 2019. These data were analysed by Frankemölle et al (2022), who showed that they paint a consistent picture of the Se-75 emission on both the time scale of the initial puff as well as on the time scale of the residual release. In the first tab of the Excel file, the different data included in the rest of the excel file are briefly discussed. Included data - On-site meteorological data - In-stack measurements of Se-75 source term - On-site measurements of ambient dose equivalent rates - On-site deposition measurements - On-site concentration measurements