English court finds BHP liable for Brazilian dam collapse

On 14 November 2025 the English High Court handed down judgment in Município de Mariana v BHP. The court ruled in favour of the claimants on Brazilian law issues of liability in an action arising from the collapse of Samarco’s Fundão tailings dam in southeast Brazil on 5 November 2015.

The judgment is available here: Municipio de Mariana & ors v BHP Plc & BHP Ltd [2025] EWHC 3001 (TCC).

Key takeaways

• A Brazilian law judgment: The parties were in agreement that Brazilian law applied to determine liability.  So, this is a judgment applying Brazilian law to Brazilian facts.  It does not reflect English law principles applicable to mass tort or environmental claims. However, once the English court took jurisdiction, the Brazilian local law strict liability regime was bound to apply. So, what it clearly illustrates is the importance of ensuring that jurisdiction battles, to which English law will apply, are litigated as forcefully as possible. Closely tied to this, of course, is the position on the funding available for mass claims in England:  it is recognised that in many other jurisdictions it is much harder for claimants to secure the considerable funding which they need to make these claims economically viable.

• Broader impact on the UK environmental claims landscape: Litigation funders and claimant lawyers may be encouraged to bring similar claims because of the progress of this complex case through the English courts, the courts’ detailed consideration of Brazilian law and the success of the claimants in the final outcome.

• BHP strictly liable under Brazilian Environmental Law: The court found that BHP were strictly liable under the Brazilian Environmental Law as “polluters” despite the dam being owned and operated by a joint venture company.

• BHP also liable under the Brazilian fault based regime: In addition to their strict liability, the court said that it would have found BHP liable under the Brazilian law fault based regime for not remedying issues with the dam and raising its height in spite of those issues. 

• Next steps: The first stage trial judgment decided the key issues of liability, but the court has not yet determined what recoverable losses the claimants have suffered. In addition, whilst the court considered the scope of releases in a selection of sample settlement agreements, the court still needs to decide (or the parties need to agree) what impact these decisions have on the 200,000 claimants who have been compensated under redress schemes. The second-stage trial is currently scheduled for October 2026.

Overview and background

The dam was owned and operated by Samarco Mineração SA (“Samarco”), a Brazilian joint venture company jointly owned by Vale S.A. (“Vale”) and BHP Brasil Ltd (“BHP Brasil”). BHP Brasil was part of the BHP Group.

Various proceedings have been issued in Brazil in relation to the collapse. Redress schemes have also been put in place. The present judgment was given in proceedings brought in the English courts by lawyers acting for more than 600,000 claimants seeking compensation from BHP Australia and BHP UK (together “BHP”), the ultimate parent companies of BHP Brasil.

In 2019, BHP were initially successful in having the English claims struck out as an abuse of process because the way they cut across the proceedings and redress schemes in Brazil made them unmanageable, pointless and wasteful. The first instance judge also ruled in favour of BHP Australia’s forum non conveniens jurisdiction challenge. However, the claim was issued before the end of the Brexit transition period, so no such jurisdiction challenge could be brought by BHP UK (as a UK-domiciled company subject to mandatory jurisdiction). Rather, the first instance judge said he would have stayed proceedings against BHP UK under the applicable EU jurisdiction regime. 

However, the Court of Appeal reversed the judge’s strike out and jurisdiction decisions in November 2020. Further details on this decision can be found here. 

The present judgment contains the court’s rulings on the issues dealt with in the first stage trial which was heard in London between October 2024 and March 2025. The trial was primarily concerned with BHP’s liability for the dam collapse as a matter of Brazilian law, but also dealt with questions about limitation and the effect of settlement agreements. 

Liability of BHP under Brazilian law

The court began by ruling on the causes and foreseeability of the dam’s collapse based on evidence from geotechnical expert witnesses and the Fundão Tailings Dam Review Panel report produced in the aftermath of the disaster. It concluded that the structural factors that made the dam unstable had been foreseeable before its collapse. Having come to that conclusion, the English court had to answer three main questions regarding BHP’s liability under Brazilian law: 

Strict liability

Question: Were BHP strictly liable as “polluters” in respect of damage caused by the collapse, pursuant to Articles 3(IV) and 14 of Brazil’s Environmental Law?

Answer: Yes.

The court held that BHP were strictly liable (i.e. regardless of their fault) under Brazil’s Environmental Law. As usual, the court reached its conclusions about Brazilian law based on evidence from Brazilian law expert witnesses.

In coming to the conclusion that BHP were strictly liable, the court adopted a broad concept of “polluter” (which includes “indirect” polluters) based on a multifactorial approach adopted in Brazilian case law. The court observed that Brazilian cases had considered factors such as: control over the activity; the creation of risk, participation and/or active involvement in the activity; financing of the activity; and economic benefit derived from the activity. 

Although BHP UK and BHP Australia were separate legal entities from Samarco (which operated the dam), the court found that they (together with Vale) were “the ultimate owners, controlling shareholders and the directing mind of Samarco”. This was because Samarco’s corporate governance structure enabled them to exercise control over its activities and they did (in fact) exercise that control and assume responsibility for risk assessment, control, mitigation and management. The court also found that BHP reviewed, assessed, approved and funded projects to increase production capacity and raise the height of the dam (which, the court found, had led to the circumstances which provided the trigger for the collapse).

In addition, the court found that the Brazilian law test for whether the relevant activity caused the alleged damage was the “but for” test for causation (i.e., “but for” the activity, would the damage have occurred?). It also rejected BHP’s submission that, as a matter of Brazilian law, the claimants had to seek redress from the primary cause of the pollution before they sought redress from BHP as “indirect polluters”.

Fault-based liability

Question: Are BHP liable by reason of fault in respect of damage caused by the collapse, pursuant to Article 186 of the Brazilian Civil Code?

Answer: Yes. 

The court concluded that BHP were liable for the collapse under the Brazilian fault-based liability regime. In line with its conclusions on strict liability, the court held that BHP had assumed responsibility for the identification, assessment and mitigation of risk at Samarco and the management and control of the dam itself. The court said that this gave rise to a Brazilian legal duty to avoid harm caused by any negligent acts or omissions. 

The court found that BHP knew or should have known about inadequate drainage and other issues in the dam’s structure as well as deficient risk/audit controls and the need for further studies and analyses about the functioning of the dam. It concluded that these acts and omissions were a direct and immediate cause of the collapse (which, it held, was the relevant causation test for this provision of Brazilian law). 

Liability as controlling shareholders 

Question: Are BHP liable as controlling shareholders of Samarco (which operated the dam) by reason of abuse of power in respect of damage caused by the collapse, pursuant to Articles 116 and/or 117 of Brazil’s Corporate Law?

Answer: No. No liability was established under Articles 116 and 117 of the Brazilian Corporate Law (regarding controlling shareholder abuse) on the facts. The court found that the duties under these provisions were only actionable by subsidiary companies and did not create direct liability to external third parties such as the claimants.

Other questions before the court in Mariana

The court found that the claims were not time-barred under Brazilian limitation law. It also made some general findings about the interpretation of Brazilian law settlement agreements, as many victims of the disaster had already accepted compensation through settlement schemes in Brazil. However, the court has not definitively decided whether individual claimants are actually barred by their settlements – that will be dealt with by the parties or determined by the court at a later stage.

What does this mean for future actions in England? 

As Mariana was a judgment about the interpretation and application of Brazilian law, the court’s conclusions, strictly speaking, are not relevant to cases governed by different laws.

However, there are some interesting parallels with the way English law (and other systems which follow it) treat issues of parent company liability . 

In that respect, the UK Supreme Court has previously held that general tortious duty of care principles will apply to parent companies’ liability for the activities of overseas subsidiaries. Whilst the specific facts of each case are important, what matters in English law, similar to the Brazilian law applied in Mariana, appears to be the extent to which the parent avails itself of the opportunity to control and intervene in the management of the relevant operations of the subsidiary. For more detail, see our discussions of the cases of Vedanta v Lungowe [2019] UKSC 20 and Okpabi v Royal Dutch Shell [2021] UKSC 3 here and here.

At a general level, these cases, therefore, illustrate to multinational companies  that their practices and procedures may be subject to detailed scrutiny in the courts following environmental disasters or other crises. This, and attendant liability risk, remains something for them to be aware of whilst balancing such issues against appropriate management and control of group activities. 

In terms of broader litigation risk before the English courts, it is significant that Mariana was a case that was issued before the end of the Brexit transition period. As a result of EU law, BHP UK had a limited ability to challenge the English court’s jurisdiction (which had a knock-on effect on BHP Australia’s jurisdiction challenge). While there is now more scope for English domiciled defendants to challenge jurisdiction on the basis of forum non conveniens, the recent English court decisions in Dhan Kumar Limbu v Dyson Technology [2024] EWCA Civ 1564, where post-Brexit jurisdiction challenges were, albeit on the facts, rejected, indicates that the English courts remain a sticky jurisdiction (see our post about the Court of Appeal decision here).

Perhaps of most significance is that the claimants’ success may encourage litigation funders and claimant lawyers seeking to bring further claims in the English courts. Although the substance of the judgment may not directly assist in future claims which do not concern the relevant Brazilian law, the progress of the case does show the English courts’ willingness to manage very large, complex multi-jurisdictional claims and apply foreign law comprehensively and, perhaps of most importance in this context, the judgment clearly shows that the English courts are willing to find multinational businesses liable in claims for enormous amounts of compensation (although the precise financial figure remains to be determined in the Mariana case), which will undoubtedly be attractive to litigation funders and claimant lawyers. 

Next steps

The Mariana judgment decided the key issues of liability in the case at first instance. However, the decision is subject to any appeal and the court has yet to determine what recoverable losses the claimants have suffered. 

The parties, and/or the court, also need to consider the extent to which individual claims have been waived because approximately 200,000 claimants have been compensated under redress schemes or entered into settlements. The first-stage trial judgment dealt with certain matters of general principle and ruled on particular sample agreements, but has not determined the impact of these rulings on individual claimants. However, the court’s ruling does mean that (in exchange for the compensation which they have already received) a large number of claimants may have waived their entitlements to some or all of the damages which they would otherwise be awarded.

A case management hearing to deal with permission to appeal and other matters is set to take place in mid-December 2025. The second-stage trial on damages is currently scheduled for October 2026.