Mrs Justice O’Farrell has handed down judgment in the liability trial of Mariana v BHP, on behalf of more than 620,000 claimants, in a case valued by their lawyers Pogust Goodhead at £36bn.
The litigation-funder-backed case, supported by investment manager Gramercy in a landmark deal, was heard by O’Farrell from October to March and involved the 2015 collapse of the Fundão Dam, resulting in 19 deaths following the release of 45 million cubic metres of iron ore tailings due to liquefaction.
In a 222-page judgment, O’Farrell found the defendants – BHP, through its UK and Australian entities – to be strictly liable. Delivering her judgment remotely, she said the “risk of collapse of the dam was foreseeable”, describing the evidence that the dam was unstable as “overwhelming”.
She found the defendants to be in strict breach of Brazilian environmental law, being classified as “polluters”; however, a linked claim involving Brazilian corporate law was rejected. O’Farrell also found in favour of the claimants on limitation of actions, holding that the claims were not time-barred until September 2029 at the earliest.
Additionally, the defendants, through their joint venture subsidiary with Vale and dam operator Samarco, were “directly and/or indirectly responsible for the activity of Samarco in owning and operating the Fundão tailings dam”.
Many local authorities who had brought the claim were found to have standing to do so. She also made various legal findings as to the principles applicable to the proper construction of a sample set of settlement agreements for the purposes of determining, at a future stage, whether other claimants had waived their right to bring claims.
A second trial is scheduled from October 2026 to assess potential damages, although BHP, which instructed Slaughter and May, has confirmed that it will appeal the ruling.
Brandon Craig, BHP’s Americas president, said: “We will continue to defend this action. The court has upheld releases provided in Brazil, and 240,000 claimants in the UK group action who have already been paid compensation in Brazil have signed full releases. We believe this will significantly reduce the size and value of claims in the UK group action.”
He argued that settlements in Brazil were “the most appropriate avenue to provide full and fair remediation to those impacted”, while acknowledging that the collapse was “a terrible tragedy”.
Pogust Goodhead’s chief executive, Alicia Alinia, who succeeded founder Tom Goodhead as CEO in August following well-publicised changes in management at the firm, said: “Today’s ruling delivers long-overdue justice to the thousands whose lives were torn apart.”
She added: “It sends an unmistakable message to multinational companies around the world: you cannot disregard your duty of care and walk away from the devastation you caused. Liability has been established. BHP is now compelled to answer for its actions and pay what is owed.”
Harris Pogust, one of Pogust Goodhead’s founders, who stood down in December 2024, praised Goodhead and fellow lawyers at the firm and in Brazil. Pogust wrote on LinkedIn: “Tom put this case in front of anything else in his life, as did many amazing lawyers who were at [Pogust Goodhead] at the time but who are no longer there.”
He added: “In my 38-year legal career I have never worked with such an amazing group of brilliant, amazing, ethical lawyers who actually cared more about the clients than they did about the fee.”
Tom Cummins, an Ashurst dispute resolution counsel, said the case could be seen as a test of the UK courts’ capacity to adjudicate complex mass tort claims, having been initially struck out based on “irredeemable unmanageability”, a decision that was overturned on appeal.
Although governed by Brazilian law, “the judgment provides valuable pointers on how the English court will assess questions of corporate control and responsibility for overseas harm”, he said.
Other claimants would recognise the court’s capacity to resolve complex claims under laws other than its own, he added, including procedural mechanisms allowing the disclosure of internal corporate documents to support allegations of corporate control.
With the scale of quantum and damages remaining “some way off”, he noted that “pursuing cases of this nature is an expensive and onerous undertaking, with no guarantees as to the outcome”.
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