Behind the postcard images of Marseille's calanques lurks a less ydillic reality...

The pollution of Marseille's calanques, caused by the city's industrial heritage, has been officially recognised by the courts, which have ordered the State to undertake a vast clean-up project by June 2028. The aim is to eliminate 77 deposits contaminated by heavy metals, spread over 29 hectares, at an estimated cost of 150 million euros.

The origin of this pollution dates back to the 19th century, when Marseille was a major industrial centre producing acids, hydrocarbons and lead. Despite the cessation of activities in 2009 with the closure of the Legré-Mante plant, the toxic residues are still present and extend beyond the calanques, carried by the wind to surrounding districts such as Mazargues and Prado.

The courts responded to the mobilisation of environmental associations and local residents by ordering the State to take action. However, the details of this intervention raise questions. Two methods are envisaged: excavation of the polluted soil under strict safety conditions, or burial under a layer of reinforced concrete, a quicker solution but one that requires ongoing maintenance to prevent further dispersion of the pollutants.

However, doubts remain about the actual scale of the work. The prefecture is referring mainly to safety measures, which could be limited to the installation of fencing to prevent access to contaminated areas. The first works, prioritising 20 sites between Mont Rose and Callelongue, are due to start in September 2025, but their exact scope remains uncertain.