The company told AFP news agency that the incident was recognized Wednesday morning at 1:50 am “in a ferric chloride solution storage tank in the production workshop at the Kem One site in Lavéra”.
This very corrosive chemical, used in particular for the treatment of wastewater, turned into a brown substance when it poured into the sea, forming a toxic layer of about six hectares at the cove of Auuguette.
Forty men from the Marseille fire brigade battalion (BMPM) and ten firefighters were sent to the scene.
The leak has now stopped, but authorities have banned boating, fishing and bathing activities in the area between Ponteau beach and Cape Couronne, in the Gulf of Fos.
An investigation has been opened into the incident.
The French Minister for the Ecological Transition, Barbara Pompili, declared on Twitter that “any damage found will be repaired by those responsible”.