When transferring the contents of a cistern by pressurised discharge into a plastic tank, 58,000 litres of fertiliser spilled on the ground. The pressure and heat, suspected of having compromised the mechanical strength of the shell, contributed to tearing one of the tank sides. Despite being placed inside a retention basin, this tank’s rupture still caused a wave that flooded 150 m² of earth before flowing by gravity over some 100 metres. The lawn and a walnut tree were burned by the fertiliser within the 1st affected zone. The THEOLS river, running 250 metres away, was at risk of being polluted by precipitation during the following days, but no drinking water extraction point was located in the vicinity. The heat evaporated a large proportion of the dissolution water (26% according to the Safety Data Sheet). The operator was required to: recover the matting imbibed with fertiliser for spreading on farmland (provided the land was not adjacent to any watercourses and moreover the spreading surface area was large enough to avoid excessive concentrations); replace matting in an attempt to desorb the hard-packed surface of the sheep pen; facilitate evaporation by the sun, if possible, by stripping the topsoil on all affected parcels; monitor a vegetable garden planted between the accident site and a far slope; and lastly warn authorities assigned to protect water resources in the event of river pollution. The operator was also asked to replace the plastic tank by a 90-m³ metal one.