Beneath the quiet town of Wittelsheim in the Haut-Rhin region of France, an abandoned potash mine called StocaMine holds 42,000 tonnes of toxic industrial waste, including harmful substances like asbestos, arsenic, mercury, and cyanide. Originally proposed in 1999 as a temporary storage site for non-radioactive waste, the mine has since become a permanent containment facility. The waste is stored more than 500 meters underground, directly beneath one of Europe's largest groundwater aquifers. This aquifer is a critical source of drinking water for millions of people, including residents of Strasbourg and areas across the German border. A fire at the site in the early 2000s stopped further waste from being added and caused parts of the mine to collapse. This subsidence has made it increasingly difficult and dangerous to retrieve the waste. As a result, in 2017, the French government authorized the removal of 93% of the mercury waste. However, in 2021, authorities decided to permanently seal the remaining waste in place, abandoning the idea of future retrieval. This decision has drawn criticism from environmental groups and the European Collectivity of Alsace, who challenged the move in court. In June 2025, the Strasbourg administrative court ruled in favor of the government, allowing the permanent confinement to continue. Officials from the Ministry of Ecological Transition argue that further delays would increase the risk of environmental contamination due to the mine's continued collapse. They warn that once the decade ends, it may become impossible to safely intervene. Despite the court’s decision, local residents and environmental organizations, including the Destocamine collective, continue to push for a more comprehensive retrieval effort. They argue that while the situation is complex, there may still be time to act before the mine becomes completely inaccessible. The StocaMine site highlights a larger challenge faced by industrialized societies: how to manage hazardous waste over the long term, and whether past containment strategies can be trusted to remain safe indefinitely.