Stocamine: French toxic waste site threatens Europe's key water source

For more than 25 years, thousands of tonnes of toxic waste have lain buried beneath the old industrial town of Wittelsheim in France’s northeastern region of Alsace. 

Some 42,000 tonnes of toxic waste currently lie buried 500 metres below the site, which contains 125km of tunnels.

On June 17, a Strasbourg court ruled that there was not sufficient time to remove toxic waste safely from the former potash mine, known as Stocamine, at the site. The court argued that the risk that the galleries could deteriorate or collapse made removal of the waste extremely dangerous. 

A press release from the Strasbourg court on May 15 stated that the studies presented in the file demonstrated that the site would only be accessible in “sufficiently safe conditions until 2027/2028”. 

After examining all the possible options in terms of environmental risks, the public rapporteur ordered that the waste should be permanently sealed underground, and that it be smothered in thick concrete walls to prevent it from leaking out. 

But scientists and advocacy groups fear that the toxic waste risks seeping into Alsace’s water table, one of the most important groundwater resources in Europe. 

Swiss geologist Marcos Buser, tasked with guiding studies and decision-making about the future of the mine’s toxic waste storage in a 2011 committee of experts on Stocamine, predicts that if water seeps into the mining sites, “pollution in the form of a contaminant plume could extend several kilometres long into the water table, hundreds of metres wide and 30-40 metres high".

Buser added, "In 20, 30, 50 years, people will say: they were crazy not to remove this waste when they could have done so." 

The geologist stressed that it is still possible to remove the chemicals. He believes the real reason French authorities don’t want to do so is due to undeclared chemical waste inside the mine.  

The committee had already recommended and approved a partial destocking of heavy metals such as mercury in 2011. This took place between 2014 and 2017 as a compromise between non-retrieval and full retrieval of the deposited inventory.

According to Buser, during that period of between 2014 and 2017, engineers and Stocamine employees discovered that about 20 percent of the big chemical waste bags that were torn contained chemicals that didn't match their labels – that they were falsely declared waste.

Buser thinks that economic considerations led to the acceptance of the undeclared chemicals. “The managers of Stocamine simply accepted any waste to keep the company alive," according to an investigation published in 2023 by Investigative Journalism for Europe.

The geologist, who has worked in various destocking projects, such as the Sainte-Ursanne case in Switzerland, said that removing chemicals from the mine in Alsace is possible and that the current decision of permanent confinement is unacceptable while safe access to the mine is still possible

'It also concerns Switzerland, Germany'

Alsace Nature and the Collectivité européenne d'Alsace (CEA) have since appealed the Strasbourg court's decision to the Nancy court, where the case is now pending. Both groups told FRANCE 24 that they are not backing down from their fight to have the waste removed from the site.

In an email, CEA President Frédéric Bierry said that several mechanisms are still available for making appeals, including referral to European courts – specifically the European Court of Human Rights or the Court of Justice of the European Union – on the basis of the right to a healthy environment.

Alsace Nature, the advocacy group that previously filed an appeal with the European Court of Human Rights – rejected under the emergency procedure – says its complaint remains under review and maintains that the Stocamine case goes well beyond a regional issue.

“It goes much further,” said the group’s director Stéphane Giraud, pointing to cross-border risks. “It concerns Switzerland, Germany and several million [people] who live off this water table.” 

Giraud warns that the long-term consequences of waste confinement are unpredictable, affecting not just water quality but the entire environmental and economic fabric of the region.

As to health risks for Stocamine employees, no link has been officially established. “We don’t know what’s really in the mine,” Giraud said, adding that workers live “in a world of mining", which makes the risks difficult to confront.

Even those opposed to burying the waste permanently are hesitant to speak publicly. “It’s a bit of a betrayal of their lives,” Giraud explained, noting that the mine was once a celebrated social model in the Haut-Rhin region.

In 1997, the French government authorised the conversion of the mine into a waste repository to keep the economy of the town going, as it was suffering after the decline of potash mining.

The project was presented as a job-creating initiative for former miners, but only 24 jobs were created and a 2002 underground fire in block 15 of the structure put an end to the reception of new waste, further eroding public trust in the facility.

FRANCE 24 contacted Céline Schumpp, Secretary General of Les Mines de Potasse d’Alsace (MDPA), the company which succeeded Stocamine, for further comment on its position regarding the permanent sealing of the site.

She referred to documents already available on the company’s website, the Conseil d'Etat's decision on 2024, a report from Cour de Comptes – France's top court for auditing public funds –  on the case and stated that, “MDPA does not comment on court decisions; it enforces them.” 

The company maintains that due to the ongoing convergence of the mine leading to the gradual collapse of its tunnels, there is no longer a safe window to completely remove the waste and therefore supports that it be permanently sealed.