The High Court in London handed down judgment on 14 November 2025 in Municipio de Mariana v BHP Group, finding BHP liable under Brazilian law for the collapse of the Fundão dam in Minas Gerais in 2015. The BHP Mariana dam judgment, given by Mrs Justice O'Farrell in the Technology and Construction Court as [2025] EWHC 3001 (TCC), followed a first stage trial heard between October 2024 and March 2025, according to the court's summary.
The dam collapsed on 5 November 2015, releasing more than 40 million cubic metres of iron ore tailings, killing 19 people and destroying the village of Bento Rodrigues. It was owned and operated by Samarco, a joint venture held equally by Vale and a BHP subsidiary. More than 600,000 claimants, including Brazilian municipalities, seek compensation in England in proceedings founded on the UK listing of the BHP companies at the time of the collapse.
What the court decided
The court held that, through their control and operation of Samarco, the BHP companies were polluters under Brazil's Environmental Law and strictly liable for the resulting damage. It also found fault-based liability under Article 186 of the Civil Code: by August 2014, BHP knew or should have known of serious problems with the dam's drainage, beach width and stability, and it was not reasonable to keep raising the dam. The court rejected the claim that BHP abused its power as a controlling shareholder under Brazilian corporate law.
On limitation, the court held that the claims are not time-barred, finding among other things that criminal proceedings in Brazil interrupted the prescription period until at least September 2024. It also set out the principles for assessing settlement agreements and waivers signed by many claimants, and held that the municipalities have standing to bring their claims.
What happens next
The court's summary explains that questions such as the date on which individual claimants suffered damage are matters for a second stage trial, where the principles set in this judgment will be applied. Parent companies with overseas operations will study the BHP Mariana dam ruling closely, in particular the court's approach to applying foreign environmental and civil liability rules. The full judgment is published on the Judiciary website.
