1 ‘Reversibility’ – the promise
As we pointed out in the last article, the history of hazardous waste disposal on and in landfills is, in the broadest sense, a history of failures. A look at the condition of such landfills shows that the original safety concepts for this type of facility, in the vast majority of cases, only last a few decades at best, and these facilities therefore very quickly become extremely expensive remediation cases. The list of failed projects is long and grows every year. What is interesting here is how little interest there generally is in the technical and historical reappraisal of these failed facilities – or even in the failure of the scientific and technical concepts that underpin them. Politicians, authorities and scientific institutions are basically not interested in analysing scientific failures, which of course always involve a certain risk and possible damage to their reputation. This also applies to the Stocamine underground waste disposal site in the potash basin of Alsace, north of Mulhouse (France), which we will now briefly examine as the first case study in our series on failed storage projects for highly toxic waste in the geological subsurface.
In autumn 2010, the two authors of this article were appointed as experts to the ‘Comité de pilotage’ (Steering Committee) of the Stocamine underground waste disposal site, which was set up by the French Ministry of the Environment and comprised renowned scientists from various nations. And this is how it came about:
The Stocamine underground storage site for class ‘0’ and ‘1’ hazardous waste came to broad attention of the public in autumn 2002 when a fire in a storage area 550m underground caused severe damage to the supporting structure of the surrounding galleries and led to the temporary suspension of storage operations. The police investigation revealed a multitude of shortcomings in the operation and safety of the facility, which ultimately led to the project being definitively abandoned in September 2003. Now the French state, as heir to the failed project, was faced with the question of what to do with the waste already stored in the deep geological disposal site. Originally, the project had been approved by the Prefect of the Haut-Rhin region under the condition that the waste would be stored for 30 years and that after this period it would be decided whether it would be left on site or whether it should be recovered. Leading representatives from national and regional politics, business and administration had lobbied hard for the project and placed the question of the reversibility of the decisions – the so-called ‘reversibility’ – at the forefront of the process.
Between the definitive cessation of operations and the appointment of the expert committee ‘Comité de pilotage’ (Steering Committee), abbreviated to COPIL, the French state had been looking for ways to steer the project that had come to such an inglorious end in such a way that, contrary to the original public declarations on the retrievability of the waste, the hazardous waste could nevertheless and definitively be left at depth. The responsible politicians and authorities therefore cautiously pursued a policy aimed at the definitive containment of the waste. The law was first amended in 2004 making leaving the waste on site legal. But the strong opposing forces in Alsace and at the site itself, which advocated recovery, had to be involved somehow in order to lend the necessary legitimacy to the authorities’ final decision. So, several years passed, during which various other mining and chemical experts carried out their investigations into the relocation and made their recommendations. Nevertheless, all these experts lacked the necessary legitimacy to release the failed project from the reversibility trap. It was not until the Minister of State for Ecology, Energy, Sustainable Development and Spatial Planning, Jean-Louis Borloo, decided to close down the ‘Mines de Potasse d’Alsace’, the local potassium mine, that the matter began to move forward again. Of particular importance was the decision not only to investigate the possible modalities of permanent containment or retrieval, but also to conduct a public dialogue on the necessary acceptance of the measures. The corresponding report by two high-ranking mining engineers, available in June 2010, expanded the debate by adding another option, which envisaged retrieving only the particularly toxic waste from the repository. The Ministry of Environment then initiated an examination of these recommendations and appointed a ‘Commission d’Information et de Suivi’ (Information and Monitoring Commission) or CLIS, and initiated the corresponding steps for the establishment of the expert commission ‘Comité de Pilotage’ (COPIL).
2 The turning point
This expert group COPIL was appointed by the Vice-Presidents of the General Council for the Environment and Sustainable Development and the General Council for Industry, Energy and Technology, respectively. Its task was to determine the conditions under which the two possible options for the closure of the waste repository operated by Stocamine could be implemented: definitive confinement underground or partial or complete retrieval of the stored waste under the primacy of reversibility. The expert group submitted its report in July 2011. In this report, it presented a majority and a minority position. These two positions can be briefly summarised as follows:
Majority position: The majority position, which was supported by 10 scientists, recognised that the retrieval of the waste was possible in principle. However, it was of the opinion that the mining risks involved in retrieving all the waste were too great for work safety reasons, and that containment of the waste as a geological repository for chemical toxic waste should therefore be implemented. This was the case even though the majority position considered it proven that at some point in the future caustic solution would penetrate the repository and then be expelled, and that the definitive, i.e. permanent, containment of the waste would therefore not be ‘acceptable’ (Figure 1). However, the possible risk of groundwater contamination resulting from this were not considered sufficiently relevant to order the evacuation of the entire repository. The majority position therefore recommended selective (partial) removal of the most toxic waste – mercury-containing waste and possibly other waste. The majority position also affirmed that retrieval was a more expensive option than leaving the waste on site.
Figure 1: Schematic representation of the flooding problem of the Mines de Potasse d’Alsace (MDPA): The flooding of the storage area can either take place through zones of weakness along the sealed off accesses, or via the lower potash seam. The mined areas were lowered in a controlled manner after mining, whereby the debris accumulations generated by the lowering may have opened, and thus water-permeable horizons, which short-circuit with the chimney-like continuing zones of weakness above the storage galleries. The long-term flooding of Stocamine is admitted by all the expert committees and consultants.
Minority position: The minority position represented by the two authors of this paper is based on experience in dealing with current hazardous waste landfills as well as experience in the emplacement and retrieval of chemical toxic hazardous waste in German underground mines, which showed that retrieval and treatment of the Stocamine waste is the safest strategy in terms of environmental impact and also to be considered the most cost-effective scenario. Technically, retrieval is still possible despite increased convergences. Experience in securing ceilings and paraments (side walls) is state of the art. The ceilings could easily be secured with anchors (threaded rods). The dismantling of hazardous waste landfills shows that chemical work safety measures have also been mastered. Robotics is now routinely used in mining. The recovered waste could therefore be repackaged under the given precautions and sent to the various destinations (treatment, detoxification, repackaging, re-storage in appropriate underground storage sites, etc.), including in German underground disposal sites (see Annex 5 of the French edition of the 2011 COPIL report).
Abstentions: One expert abstained.
On 12 December 2012, the ministries in Paris decided to implement the strategy of selective retrieval of particularly toxic waste adopted by the majority position. At the request of the regional mandate holders, it was decided to further involve the public, which took place between 15 November 2013 and 15 February 2014. The report of the ‘Conseil Général de l’Écologie et du Développement Durable’, published in March 2014, advocated the removal of the majority of mercury-containing waste. This recommendation was followed by the new Minister of the Environment, Ségolène Royal, who in August 2014 spoke out in favour of the removal of 93% of the hazardous waste containing mercury. However, she fell short of the statements she had made on Stocamine in 1992: “The important thing, this is the principle, which is also taken into account in the Stocamine project, of the reversibility of storage. It will be necessary to be able to bring out this waste, tomorrow or the day after tomorrow, when the technological means for its definitive destruction are available”.
The Stocamine company was dissolved in 2014 and its responsibilities transferred to the ‘Mines de Potasse d’Alsace’ (MDPA). At the same time, by decree of 16 June 2014, the former Information and Monitoring Commission (CLIS) was transformed into a CSS Site Monitoring Commission. The representatives of the associations working in the CSS also requested the Prefect to set up a committee to monitor the disposal work. This committee would never meet again, with the exception of a single visit to the mine. This of course raises fundamental questions, as we will see later.
In January 2015, the MDPA presented their proposal on the final closure of the site to the Prefect.
The Prefect then issued the decree of 23 March 2017 to allow the indefinite storage of the 42,000 tonnes of toxic waste, despite a public consultation marked by a high turnout and major concerns expressed by the majority about definitive disposal.
In the meantime, Stocamine started the removal of the majority of the problematic waste packages containing mercury and arsenic, as had been suggested by the mine engineers Caffet & Sauvalle and COPIL. This waste was transported to UTD Sondershausen in Thüringen (Germany), among other places, and stored there, with various batches not being accepted by the buyer. The refusal of the customer to accept and store this waste showed very clearly that – as already noted by the Prefect of the Haut-Rhin in 2011 – non-compliant waste had been stored in Stocamine. COPIL also mentioned these questionable deposits in its final report, but at the same time stated that “the labelling and mapping of the compartments appear to have been done in the correct manner”. A formulation that leaves some room for interpretation.
Nevertheless, resistance to the permanent closure remained. Resistance arose in the French parliament. It eventually led to a parliamentary enquiry, which was published on 19 September 2018. This enquiry report is likely to be one of the few overview reports that fundamentally and critically evaluated the process and governance of the project. The report also examined the various retrieval, partial retrieval and containment options and recommended the complete dismantling of the repository.
At the same time, the Bureau de Recherches Géologiques et Minières (BRGM), the French national geological service, ordered another report on the question of retrieval or definitive containment. In addition to Spanish specialists in geomechanics, two German groups were also involved in the questions: DMT GmbH and Co. KG, which is entrusted with the remediation project of the low- and intermediate-level radioactive waste in the Asse experimental repository (Lower Saxony), and the consulting firm Plejades GmbH. In addition, BRGM also called in the German company Sat. Kerntechnik GmbH for waste conditioning. Once again, different scenarios of retrieval were examined and the conclusion echoed the previous evaluations of the official reports: Retrieval is possible but costly, but from the mid-2020s increasingly difficult to unfeasible.
On 12 December 2012, the ministries in Paris decided to consult another consulting firm, Antéa Group-Tractabel, which drew up a further report on technical recovery and its costs, and whose conclusions were briefly mentioned in the French Environment Minister’s communiqué of 18 January 2021: the definitive containment of the waste is once again affirmed using the same line of argument.
Finally, in 2019, the consulting firm, Antéa Group-Tractabel, was called in to provide a further expert opinion on technical salvage and its costs, and its conclusions were briefly mentioned in the communiqué of the French Minister of the Environment of 18 January 2021: the permanent containment of the waste is once again affirmed with the same line of argument.
On 5 January 2021, the Minister visited the Stocamine site and held another hearing with the various parties concerned, announcing her preference for the scenario of permanent containment of all remaining waste.
In a press release dated 18 January, the Ministry of Environment announced the Minister’s decision.
Barbara Pompili’s decision to leave the waste permanently on site led to a wildfire in the Alsace region and led to the mobilisation of all forces opposed to this development.
This decision burdens the future of an entire area and leaves a toxic legacy for future generations. A decision that will have serious consequences.
3 An avalanche of high costs is on the horizon
The easiest way to see this wrong decision is to look at the development of the cost forecasts for the removal of the waste. The removal costs determined in various expert reports and calculations between 2006 and 2013 were quite comparable. The first studies on the removal of waste from the underground storage site date back to 2006. A possible scenario for this retrieval and reconditioning work, as well as the subsequent re-storage in a final repository mine in salt (for class ‘0’ hazardous waste), can be seen in Figure 2, the costs of which were estimated to be in the order of 65 million €.
Figure 2: Retrieval scenario with repackaging/reconditioning of retrieved waste, transport and re-storage, from BMG, 2006, S. 20.
For the containment of the waste and its backfilling as well as the sealing of the accesses with special concrete, the German company Ercosplan, which specialises in such work, calculated costs of € 8.8 to 21.5 million depending on the option, with option 2 costing € 12.2 million. Somewhat higher retrieval costs of € 80 to 100 million were estimated by the regulatory authority DREAL. Converted to the tonne, this resulted in cost estimates of 1,477.-€/t (retrieval costs 65 million €).to 2,270.-€/t (retrieval costs 100 million €). Based on experience with the DMS St-Ursanne remediation project for class ‘1’ hazardous waste, one of the two blog authors (MB) estimated the remediation costs to be in the order of magnitude of 1,140.- €/t (retrieval costs around 50 million €). All these estimates were within a range of a factor of 2, so they were consistent. In terms of difficulty, the retrieval of the hazardous waste from Stocamine was comparable to the remediation of the hazardous waste landfills DIB Bonfol (Canton of Jura, Switzerland) and SMDK Koelliken (Canton of Aargau, Switzerland), which amounted to 1,850 €/t and 1930 €/t, respectively. Simple calculations thus showed that, despite all the uncertainties, there was good agreement and coherence in the cost estimates.
The situation was quite different for the dismantling costs, according to the expertise of the ‘Comité de pilotage’ (COPIL) in 2011. The report of the parliamentary committee of enquiry summarises this development succinctly: “Several financial assessments of the various scenarios have been carried out in recent years. € 145 million in 2013 by [the consultancy firm] BMG; this estimate was increased to € 210 million in 2015 by [the operator Mines de Potasse d’Alsace] MDPA. However, these estimates had to be reassessed in light of the waste already removed during partial retrieval.” MDPA estimated the removal costs for three scenarios (Table 1).
Table 1: MDPA retrieval scenarios and estimated costs
The retrieval costs thus range between approx. 400 and 480 million €. Converted to the tonne of hazardous waste, this equates to 8,300- and 10,900- €/tonne. This is probably the most expensive hazardous waste ever produced in the world! And by far! For comparison: today, the German UTDs charge between about 300 and 400 € for storage per tonne and up to 1,100 € if additional conditioning work has to be done. And the vitrification costs for asbestos – the most expensive treatment option at the time – had been quoted by COPIL in 2011 as between €1,200 and €1,500. So there must be something fundamentally wrong with Stocamine.
4 The broken promise…
Why are such high costs for the removal of the hazardous waste estimated by officials, since the promoters of the project affirmed reversibility from the beginning and presented it as technically mature? And why did Stocamine pay only 305,000 € (2 million FFr.) as financial reserves into the so-called guarantee fund, which can only be regarded as a drop in the ocean? How can it be explained that only 305,000 € have been set aside, and that we are now operating with a hefty budget of at least 400 million € which is 1,300 times the money set aside? This raises not only questions of due diligence in cost control. It also raises fundamental questions as to whether these ludicrous costs are only estimated at such a high level so that there is no discussion about retrieval again.
A review of today’s removal costs by German operators of underground disposal sites still shows maximum removal costs of about 70 to 75 million €. In this context, one wonders why the offers obtained from two German underground disposal sites, which were submitted directly or as partners in a bidding consortium, have not been made public by Stocamine. And finally, one wonders why other companies operating underground disposal sites were not consulted instead of companies with experience in the nuclear sector but not in the field of chemical toxic waste? How can it be explained that the costs of disposal are now 6 to 7 times higher than those estimated by experienced disposal companies in Germany?
It is obvious that this process is primarily about reversing – in plain language, blocking – the commitment made to reversibility. But not only that: a commitment to full retrieval of the waste was never taken into account, as is clearly stated on page 10 and following the report of the Commission of Inquiry (Commission d’enquête publique , 26 January 2017) written by Messrs Lafond, Hoffner and Renckly: “We also noted that the initial organisation of the storage by positioning drums and big bags without circulation in the middle of the galleries showed that this option of reversibility had never really been taken into account.”
By abandoning their repeated promises of ‘reversibility’, the responsible state institutions and the scientific authorities involved are exposing themselves to a massive loss of trust and credibility; and not only with regard to the Stocamine project itself. The Stocamine example also undermines confidence at other sites that are confronted with deep disposal projects for highly toxic waste. The withdrawal of the reversibility obligation is likely to cast a heavy shadow first and foremost for the nuclear repository project in Bure (Grand-Est).
But, also in other countries confronted with the problem of nuclear waste disposal, the damage to credibility and acceptance is likely to be immense, for example in Germany, which launched its nuclear siting project a few years ago. In the eyes of the public, how are storage containers with spent high-level waste with a total weight of more than 20 t to be retrieved from a sealed repository mine in salt or clay over a period of up to 500 years if the French Ministry of the Environment with all its expert committees and large mining services is incapable of retrieving pallets with four 200-litre drums each or likewise palletised big-bags with a total weight of 1.5 t from an open salt mine? An operation that is now routinely carried out for the same class ‘0’ and ‘1’ hazardous wastes in every German UTD with equipment that is partly operated remotely? What is behind this defence to implement an operation routinely carried out thousands of times in the galleries of Stocamine?
5 … and the question of ‘why’?
So there must be a reason why something fundamental is being concealed. The most obvious explanation for this strange and incomprehensible behaviour is that during Stocamine’s operating period, much more misdeclared waste found its way into the depths than stated and a larger number of institutions are implicated in this case. The COPIL report noted that between June 1999 and August 2002, “20 shipments of waste equivalent to about 250 tonnes” were rejected because they did not meet the acceptance criteria (degassing, radioactivity, size and packaging of the casks). For example, the containers that were discovered on 22 June, 18 August and 30 November 1999 during the incoming inspection because they showed too much radioactivity. Where did the radioactive substances in these flue gas cleaning residues come from? From medical waste, i.e. hospitals? Why was the origin of the radioactivity not investigated? In any case, the regularity of the rejections in 1999 shows that these were recurring events, i.e. deliveries that were repeated on a regular basis.
But other waste was also stored that had to be recovered later, sometimes at great expense. Among them were containers that the Prefect ordered to be removed from storage by order of 10 July 2000. The COPIL report mentions that the 173 waste packages from unit 11 that were recovered in 2001-2002 contained PCB oils. Various faulty batches had been delivered on 11 February 1999 – shortly after the opening of Stocamine – as well as on 5 July 1999 and 21 January 2000.
The succession of incidents inevitably raises questions about the reliability of Stocamine’s system of incoming inspections. The fire in September 2002 proves the extent to which this entry procedure was deliberately circumvented. The subsequent judicial investigation confirmed this violation of rules leading to the conviction of the management. In this case, too, the pattern of repetition can be seen and similar questions arise. 173 containers containing PCBs had been stored undetected? Over a period of almost 1 year! All housed in Block 11. What prompted the Prefect to demand this re-storage? Half a year after the delivery of the last wrong batch? These are disturbing questions that have not yet received a satisfactory answer, but could explain why Stocamine and the French state and its ministries and experts are positioning themselves so systematically against the retrieval of the waste.
And there are indications that a lot more re-declared, i.e. non-compliant, waste was stored than officially admitted. A witness told one of the two blog authors (MB) that canisters of industrial or commercial oils and fats could also be found, as well as medical waste, including syringes and surgical instruments. The falsely declared waste containers are numerous (perhaps up to 20% of the containers). And yet another circumstance clearly indicates that observers were as unwelcome as possible: As mentioned above, Stocamine did not ask the monitoring committee to supervise the work of the retrieval operations. The management always rejected external control. The regularly invoked transparency was never really put into practice. This could explain the inertia of the authorities and the blocking of the retrieval work since 2002. But does this attitude justify the expenditure of almost half a billion euros of public money? Clarifying this is no longer a case for geologists and other experts, but primarily a case for the judiciary.
 Marcos Buser, Funkackerstrasse 19, 8050 Zürich, email@example.com
 Walter Wildi, Chemin des Marais 23, 1218 Le Grand Saconnex
 See also Buser, Marcos, Wildi, Walter, 2018, Du stockage des déchets toxiques dans des dépôts géologiques profonds, Science & Pseudo-science, Avril-Juin 2018 ; Buser, Marcos, Forter, Martin, Wildi, Walter, 2019, Entsorgung von Sondermüll in der Schweiz, von der Verdünnung im Rhein zum Sarkophag von Teuftal, Swiss Bull. angew. Geol., Vol 24/2 = Hazardous waste disposal in Switzerland, from dilution in the Rhine river to the sarcophagus of Teuftal, Swiss Bulletin for Applied Geology, vol. 24, n° 2, p. 27-41
 NEA, 2014, Loss of Information, Records, Knowledge and Memory – Key factors in the History of Conventional Waste Disposal, Nuclear Energy Agency, Paris, NEA/RWM/R(2014)3, https://www.oecd-nea.org/jcms/pl_19472/loss-of-information-records-knowledge-and-memory-key-factors-in-the-history-of-conventional-waste-disposal?details=true
 Assemblée Nationale, 2018, Rapport d’information déposé par la mission d’information commune sur le site de stockage de déchets Stocamine, 18 septembre 2018, https://www.assemblee-nationale.fr/dyn/15/rapports/micstoc/l15b1239_rapport-information
 Caffet, Marc, Sauvalle, Bruno, 2010, Fermeture du stockage de déchets ultimes de Stocamine (Haut-Rhin), Ministère de l’écologie, de l’énergie, du développement durable et de la mer & Ministère de l’économie, de l’industrie et de l’emploi, 6/2010, https://cgedd.documentation.developpement-durable.gouv.fr/notice?id=Affaires-0005266
 Copil, 2011, COPIL Stocamine, Gutachten, Juli 2011, http://www.grand-est.developpement-durable.gouv.fr/IMG/pdf/COPILfinalallemand.pdf
 Berest P., Brouard B., Feuga B., 2004, Abandon des mines de sel: faut-il ennoyer? Revue Française de Géotechnique, no. 106-107, 1er et 2ème trimestres 2004, https://www.geotechnique-journal.org/articles/geotech/pdf/2004/01/geotech2004106-107p53.pdf
 CGEDD, 2014, Projet de Fermeture du Stockage Souterrain StocaMine, Concertation Publique 15 novembre 2013 – 15 février 2014, Conseil Général de l’Ecologie et du Développement Durable
 Assemblée Nationale, 2018, op. cit., Teil I, Kapitel I.2.c. >> 5
 Assemblée Nationale, 2018, op. cit., Teil I, Kapitel I.2.c. >> 5
 L’Alsace, L’écologie sereine, rubrique Environnement, 30.10.1992
 Caffet, Marc, Sauvalle, Bruno, 2010, op. cit. >> 6
 Stocamine, 2014, La lettre d’information sur les travaux de déstockage, No. 5, octobre 2014; Mitteldeutsche Zeitung, Gefährliche Industrieabfälle aus Frankreich, Sondermüll auf dem Weg ins thüringische Sondershausen, 25. November 2014, https://www.mz-web.de/mitteldeutschland/deponie-in-sondershausen-nimmt-elsaessern-giftmuell-ab-341166
 Buser, M., 2017, Short-term und Long-term Governance als Spannungsfeld bei der Entsorgung chemo-toxischer Abfälle, ITAS-Entria-Arbeitsbericht 2017-02, see attachment ENTRAI/ITAS.
 Copil 2011, op.cit., no paging >> 7: “ … The labelling and allocation of the goods in storage appears to have been carried out correctly. ”
 BRGM, 2018, Délais de déstockage total des déchets (hors bloc incendié) Stocamine: analyse du délai de 15 ans et de scénarios alternatifs, Rapport final, BRGM/RP-68334-FR, Octobre 2018.
 The Minister for Ecological Transition announces the containment of the StocaMine site and an envelope of 50 million euros to protect the Alsace groundwater from pollution risks, Monday 18 January 2021.
 Institut de Sécurité, 2006, Rapport de synthèse Étude approfondie de la variante de la mise en œuvre de la réversibilité, Institut Suisse pour la Promotion de la Sécurité, juin 2006
 BMG, 2006, Stockage souterrain de Wittelsheim : évaluation technique de la variante de la mise en œuvre de la réversibilité, BMG Engineering AG, juin 2006, p. 52; Institut de Sécurité, 2006, op.cit., p. 16 >> 21
 BMG, 2006, op. cit., S. 20 >> 22
 Ercosplan, 2008, Etude de faisabilité, Remblayage des cavités souterraines de Stockage des Déchets de StocaMine, Wittelsheim, France, Rapport final ERCOSPLAN Ingenieurgesellschaft Geotechnik und Bergbau mbH, 2 septembre 2008, p.68.s
 DREAL, 2010, Devenir du site Stocamine à Wittelsheim (Haut-Rhin) – Stockage de déchets dangereux, Rapport de la DREAL Alsace, DREAL Direction Régionale de l’Environnement, de l’Aménagement et du Logement d’Alsace, 7 avril 2010, p. 7
 Including the much higher costs of thermal treatment of the waste
 Assemblée Nationale, 2018, op. cit., p. 71 >> 5
 Copil 2011, op.cit., p. 26 >> 7: « … L’amiante peut être vitrifiée à des coûts de l’ordre de 1200 à 1500 € par tonne».
 DREAL, 2010, op.cit., p. 5 >> 23
 Copil 2011, op.cit., p. 23 >> 7: «Entre juin 1999 et août 2002, on note 20 refus de lots, représentant 250 tonnes environ, réexpédiés suite à la constatation d’une non-conformité (dégazage, radioactivité, taille et conditionnement des colis»
 DREAL, 2010, op.cit., p. 5 >> 23
 Copil 2011, op.cit., p. 23 >> 7: “Between June 1999 and August 2002, there were 20 refusals of batches, representing approximately 250 tonnes, reshipped following the discovery of non-compliance (degassing, radioactivity, size and packaging of packages, etc.).”
 Buser, M., 2017, S. 45 >> 15