Claimants in a trial underway in London’s High Court over BHP’s role in a catastrophic dam collapse in Brazil painted a grim picture of “red flags” that they allege the global miner failed to adequately address.

The long-awaited trial stems from a 2015 accident at the Samarco iron ore complex, which is jointly owned by BHP. Plaintiffs firm Pogust Goodhead represents more than 620,000 claimants who are seeking £36 billion (US$44.7 billion) in damages.