Australian mining giant BHP on Wednesday denied responsibility for a 2015 dam collapse in Brazil, one of the country's worst environmental disasters, as it opened its defence at the High Court in London.
The months-long trial will determine whether BHP is liable for the rupture at the Fundao tailing dam in Brazil that killed 19 people and unleashed a deluge of thick toxic mud into villages, fields, rainforest, rivers and the ocean.
More than 620,000 complainants, including 46 Brazilian municipalities, companies and indigenous peoples, are seeking an estimated GBP36 billion ($47 million) in damages in the civil trial.
The company's lawyer Shaheed Fatima argued BHP cannot be held as the "direct polluter" as the dam was managed by Samarco, co-owned by BHP and Brazilian miner Vale.
The tragedy in the town of Mariana unleashed almost 45 million cubic metres of highly toxic mining waste sludge, flooding 39 towns and leaving more than 600 people homeless.
The flood killed thousands of animals and devastated protected tropical rainforest.
According to the victims' lawyers, BHP was aware that an accumulation of toxic sludge, estimated at 1.3 million tonnes per year, far exceeded the annual limit set -- a build-up which they say contributed to the disaster.
BHP's other defence lawyer Daniel Toledano said the complainants have failed to point to "an act or omission from BHP from which the damage would necessarily have followed".
At the time of the disaster, BHP had global headquarters in Britain and Australia.
In opening submissions to the court Monday, the company laid out as a central argument that it "did not own or operate the dam or any related facilities".
A separate case in Brazil has seen Vale and BHP offer to pay almost $30 billion in compensation. This was increased on the eve of the London trial from almost $25 billion.
BHP and Vale estimate that more than 430,000 complainants have already received compensation, including more than 200,000 party to the London case.
BHP added that the Renova Foundation, which manages compensation and rehabilitation programmes, has already paid out more than $7.9 billion in emergency aid.
The Australian mining giant has also said that the quality of river water contaminated by the fallout has returned to pre-disaster levels.
However, a scientific paper published this year in the Franco-Brazilian geography review Confins said the dam rupture had caused "permanent effects of pollution" on the river Doce and its coastal plain.
The hearing, set to last until March, must determine BHP's potential liability for the disaster.
If BHP is ruled liable, another trial would take place from October 2026 to determine the damages.
