A court in Auckland on Tuesday found the firm Whakaari Management, which managed access to a volcanic island, guilty of failing to sufficiently protect its visitors.
In December 2019, a deadly column of burning ash and steam erupted from a volcanic vent on White Island, also known as Whakaari, killing 22 people and injuring another 25. Most of those dead were tourists.
Whakaari Management failed to "assess risk" adequately and provide them with protective equipment, the court said.
A similar eruption had taken place three years earlier. No one was injured at that time because the eruption took place at night.
"What should then have been obvious to every Whakaari stakeholder was that any risk assessment and risk management processes in place had failed," Judge Evangelos Thomas said.
While the company manages the island and gives permits to tourists to land on the island, it does not conduct the tours itself.
The court dismissed a second charge of ensuring the safety of those working on the island.
Who are the guilty parties?
Whakaari Management is the last of the 13 organizations or individuals originally charged over the fatal incident. Six of the 13, including the three brothers who own the island, have previously been acquitted.
The tourism company will now be sentenced next February with six other parties who pleaded guilty. This includes three companies that operated helicopter tours, one that operated boat tours, a scenic flight operator, and the New Zealand scientific agency GNS Science.
The guilty parties face fines up to NZ$1.5 million (about US$880,000, €850,000).
White Island was a popular tourist destination which earned the three brothers — Andrew, James and Peter Buttle — around NZ$1 million a year from tourists before the accident. Since the eruption, no tourists have been allowed on the island.