The surface concentration data collected during the European Tracer Experiment (ETEX) are analysed for the first time by means of geostatistical techniques. The aim of the analysis is to determine the self-consistency of the data, to identify anomalous behaviours of stations with respect to the spatial and time structure of the tracer cloud measurements and to characterise the correlation structure of the measured cloud. The so-called structural analysis is usually regarded as the investigation step to be conducted prior to any interpolation procedure and mapping. Given the relevance of the ETEX dataset, one of the few existing sets of information related to controlled long-range dispersion of tracers, the analysis presented here should be regarded as a way to acquire further insight into the observed data characteristics. ; JRC.G.9-Econometrics and statistical support to antifraud