More than 7000 people from the Papua New Guinea province of Madang are suing a mining company for US$5.3 billion in damages.
Last year, 200,000 litres of toxic slurry spilled into the ocean from the Basamuk nickel refinery, turning the sea red and killing marine life.
But the plaintiffs - who include villagers, scientists, chiefs and the provincial government - claim the company, Ramu Nico, had been causing environmental damage for years.
The lawyer leading the suit, Ben Lomai, says the plaintiffs want the court to declare Ramu Nico a public nuisance, and that it acted negligently.
He told Jamie Tahana that the plaintiffs believe the company knew it was causing damage.