During the morning, an industrial operator discovered a leak on the water pipeline originating from its industrial platform located nearby. This water was normally being injected into a deep geologic structure labelled “Crétacé 4000”. A layer of blackish water, corresponding to 3 or 4cu.m of effluent, had spread into the dry trench of a new pipeline that was intended to replace the previous one during the upcoming quarter. A strong thunderstorm caused a rise in the Baïse Riverbed, which had been running nearly dry for almost 3 weeks, carrying the effluent initially contained. Tens of dead fish were observed and neighbouring municipalities adopted measures to prohibit fishing, swimming and crop irrigation while awaiting the results of various tests on daphnia and germination. An emergency order imposed that the operator excavate the polluted soil, discard the section of perforated pipe, install piezometers in order to assess the state of the water layer, conduct analyses both upstream and downstream on the Baïse River (relying on IGBN indices), and improve monitoring of the current pipe prior to placing the new pipeline into service.