Industrial site discharges red mud for decades

An industrial site in Gardanne, Bouches-du-Rhône, discharged red mud containing heavy metals into the Cassidaigne canyon, a deep underwater trench 320 meters below the Mediterranean Sea, for nearly 50 years, from 1966 to 2015. This red mud, a byproduct of processing bauxite into alumina using the Bayer process, included toxic substances such as arsenic, mercury, chromium, lead, vanadium, and titanium.

Pipeline allowed toxic waste into the sea

The alumina plant used a 50-kilometer pipeline, 7.7 kilometers of which ran underwater, to discharge the red mud directly into the Cassidaigne canyon. Over nearly half a century, this practice resulted in the accumulation of tens of millions of tons of toxic waste, with estimates ranging from over 20 million to up to 32 million tons.

Discharge of solid waste stopped in 2016

A prefectural decree issued on December 28, 2015, halted the discharge of solid red mud into the sea as of January 1, 2016. Since then, the solid residues have been dried and stored on land at the Mange-Garri site. However, the discharge of liquid effluents, which still contain harmful substances like iron, aluminum, and arsenic, was allowed to continue for an additional six years.

Toxic deposit remains in protected area

The Cassidaigne canyon is now part of the Calanques National Park, yet the toxic deposit remains at the bottom of the marine trench with no active cleanup project. Environmental groups, scientists, and local residents continue to raise concerns, calling the situation a potential ecocide, while legal aspects of the case remain under review.

Efforts to manage waste face challenges

In 2015, the National Agency for Food, Environmental and Occupational Health Safety (Anses) conducted studies that led to a new decree in 2016, revising the management of the Mange-Garri site. Despite these changes, no large-scale recovery or decontamination has begun, due to the technical and financial difficulties involved. The case underscores the complex challenge of addressing industrial waste in the context of modern environmental regulations.