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Municipio de Mariana & Ors v BHP Group

Described by one London disputes head as ‘the biggest class action ever’, Municipio de Mariana & Ors v BHP Group sees a claimant class of more than 700,000 bringing claims for damages in excess of £36bn arising from the 2015 collapse of Brazil’s Fundão Dam.

On 5 November 2015 the dam suffered a catastrophic failure. Nineteen people were killed and over 40 million cubic metres of iron ore waste poured into the Doce River in what became the worst environmental disaster in Brazil’s history.

The dam was owned and operated by Samarco, a joint venture between Brazilian companies Vale SA and BHP Billiton Brasil Ltda. BHP Brazil is a subsidiary within the BHP group, headed by BHP England and BHP Australia.

The English class action was first brought in 2018. The High Court struck the claim out in 2020 but in 2021 the Court of Appeal granted the claimants leave to appeal. The Court of Appeal allowed the appeal in July 2022 and the case is currently set for an 11-week trial beginning in October this year. The High Court also in November 2023 allowed BHP to bring a part 20 claim against Vale for 50% of any damages BHP may be required to pay as a result of the litigation.

The decisions to allow the case to proceed in the English courts and to allow BHP’s part 20 claim against Vale further demonstrates the increased willingness of the English courts to handle large and complex multijurisdictional claims. The rulings build on decisions in similar environmental mass claims such as Vedanta in 2019 and Okpabi in 2021 that expanded the extent to which UK-based parent companies can be held liable for the actions of their overseas subsidiaries. Both Vedanta and Okpabi also concerned environmental disasters, in Zambia and Nigeria respectively. And a win for the claimants in Mariana would give further incentive to victims of environmental disasters to seek redress in the English courts.

BHP denies the claims in their entirety and continues to hold that the English proceedings are unnecessary because ‘all claimants have avenues in Brazil to resolve any potential claims’.

For Vale: Simon Salzedo KC, Richard Eschwege KC, Michael Bolding, Crawford Jamieson and Charles Wall (Brick Court Chambers) instructed by Lawson Caisley and Stephanie Stocker (White & Case)

For Municipio De Mariana: Alain Choo Choy KC (One Essex Court), Russell Hopkins (Temple Garden Chambers), Nick Harrison and Jonathan McDonagh (Serle Court), Antonia Eklund (Blackstone Chambers) and Pippa Manby (4 New Square) instructed by Pogust Goodhead

For BHP: Daniel Toledano KC, Nicholas Sloboda, Oliver Butler, Patricia Burns, Tamara Kagan, Maximilian Schlote, Stephanie Wood, Veena Srirangam, Jade Fowler, Michael Kotrly and Joseph Johnson (One Essex Court)

Return to Disputes Yearbook 2024 contents.