BHP has lost its bid to overturn a ruling that it is legally responsible for the 2015 Mariana dam disaster, after the Court of Appeal unanimously dismissed the mining giant's appeal in a judgment handed down on Friday morning.
Sir Geoffrey Vos, the Master of the Rolls, sitting with Lord Justice Zacaroli and Lord Justice Cockerill, rejected every ground of challenge in the case, cited as [2026] EWCA Civ 1319. The decision leaves intact the finding of Mrs Justice O'Farrell that BHP is strictly liable under Brazilian environmental law for the collapse of the Fundao tailings dam in November 2015.
The disaster
Nineteen people were killed when the dam, near the city of Mariana in the Brazilian state of Minas Gerais, gave way, releasing a torrent of iron ore waste that destroyed the village of Bento Rodrigues, swept through communities downstream and polluted the Doce river system for hundreds of miles to the Atlantic coast. It remains one of the worst environmental disasters in Brazilian history.
The claim, brought in London by around 450,000 Brazilian individuals, businesses, municipalities and indigenous communities, is one of the largest group actions ever heard in an English court. The claimants are represented by Pogust Goodhead, while BHP instructed Herbert Smith Freehills Kramer.
The Case at a Glance
- The Court of Appeal dismissed BHP's appeal in [2026] EWCA Civ 1319.
- Around 450,000 claimants are suing over the November 2015 Fundao dam collapse.
- Mrs Justice O'Farrell found BHP strictly liable under Brazilian environmental law.
- BHP must pay 43 million pounds on account of costs, with interest at 1 per cent above base rate.
- The claim now moves to the assessment of damages.
Strict liability upheld
At the heart of the appeal was a question of Brazilian law. Mrs Justice O'Farrell concluded that liability under the Brazilian Environmental Law was strict, meaning the claimants did not have to prove fault on BHP's part. The company argued that the judge had misread the statute and the Brazilian authorities on which she relied.
The Court of Appeal disagreed. In a unanimous judgment, the three justices held that the trial judge's analysis of Brazilian law could not be faulted, and that the appeal amounted in substance to an invitation to re-try factual and expert questions that had been resolved after a lengthy hearing.
Costs, interest and the funding fight
The company also failed on the financial skirmishing that followed the liability trial. BHP must pay pre-judgment interest at 1 per cent above the Bank of England base rate on the claimants' Stage 1 costs, and make a payment on account of 43 million pounds.
The court rejected BHP's argument, founded on the Supreme Court's decision in Hirachand and section 58A(6) of the Courts and Legal Services Act 1990, that the claimants' success fee arrangement should constrain what the company has to pay. The point matters far beyond this case, touching the economics of the litigation funding model on which almost every modern group action depends.
What happens next
Attention now turns to quantum. With liability settled, the High Court will move to the assessment of damages, a phase in which the claimants' total demand could run to tens of billions of pounds. BHP said it was reviewing the judgment and stressed that it continued to support compensation and remediation programmes in Brazil.
For the claimants, Friday's ruling is the clearest vindication yet of the decision to bring a Brazilian disaster before an English court. For the City, it is a reminder that London's courts remain open for business to the world's aggrieved, and that its judgments can reach across oceans.