Hydrocarbons were polluting the RHONE River Canal. First responders set up 3 floating booms, one of which was placed at the entrance to the THAU Lagoon, where many shellfish farms were operating. The pumping clean-up was performed by city crews. Navigation around the Canal de la Peyrade was prohibited for several days. Pumping operations rid the zone of pollution, but 10 days later traces of pollution reappeared between the dams. Analyses carried out to identify the type of pollutant revealed its source as a leak on a pipeline, whose precise location however required additional investigation: the acoustic method was deemed appropriate. The leaky pipeline was filled with water on 17th January. The facility operator assumed responsibility for pumping out the canal pollution and continued these clean-up efforts for several days. On 6th February, 300 m³ were pumped and recovered. The polluted zone area was assessed to cover 6.85 ha. The cost of clean-up works, by 6th February, had reached €300,000 and, according to the operator, was capable of reaching €1 million. The leak was due to strain hardening of the pipe metal material (DN 500, service start-up: 1973) subsequent to a series of shocks that had occurred during the execution of nearby municipal works.