A risk management expert has told a court it was not safe to operate any tours on Whakaari White Island - but the fact it is the country's most active volcano was used as a selling point.
It is the fourth week of a trial at the District Court in Auckland into health and safety failings in the lead up to the deadly eruption in 2019 that killed 22 people.
Victoria University lecturer in occupational health and safety, Dr Chris Peace, has nearly 50 years' experience and took the stand as an expert witness called by WorkSafe.
"In my opinion, the only control which could have eliminated that risk would be to not take tours to Whakaari," Peace said.
"If I were instructed to undertake the risk assessments on behalf of the tour operators, I would have recommended that tours could not proceed to Whakaari as the risk to workers or tourists could not be eliminated or minimised to an acceptable level without stopping tours completely."
Pearce said tour operators did not provide timely or accurate information about the eruption hazards, risk of death or serious injury and tourists could not have understood the risk they were exposed to.
"Such information might be shocking to prospective tourists and would likely deter most people from going. That is, in my opinion, a reflection of why a tour operation on Whakaari was impractical."
A tour operator disclosed Whakaari was the country's most active volcano but did not fully describe the volcanic hazards and potential for death or serious injury, he said.
Instead, he said the fact Whakaari is New Zealand's most active volcano was used a "selling point" in a tour operators' marketing.
Peace read the court this description from White Island Tours' website; "Whakaari White Island is one of the world's most accessible active volcanoes and home to unmatched geothermal activity. Experience roaring steam vents, bubbling pits of mud and hot volcanic steams as you witness first hand the powerful forces that have shaped the earth."
The three owners of Whakaari and three companies are facing charges under the Health and Safety at Work Act that allege they failed to take adequate steps to prevent serious injury or death.
White Island Tours pleaded guilty to charges brought against it by WorkSafe in June, after an investigation found the company failed to conduct risk assessments, consult with GNS Science and provide appropriate protective equipment.
It had an exclusive license with Whakaari's owners to operate tours by boat.
Peace said before the disaster in 2019, tours had been conducted for decades with few serious injuries and in 2014 he had been on a tour of Whakaari with family members.
"I did so in my personal capacity and assumed that the tour operator and other [companies involved in tours] had carried out the required risk assessment and had determined that it was safe to visit the volcano."
Ngati Awa bought White Island Tours for $9 million in 2017.
Peace said there was no evidence White Island Tours cancelled tours due to volcanic activity.
"It appears that all of the Whakaari tour operators set up their tour business on the assumption that the likelihood of an eruption on Whakaari when people were on the volcano was low, and therefore the risk was negligible," he said.
"At no stage did they re-evaluate this assumption."
The operators fundamentally failed to identify, analyse or evaluate the risks of taking tours to Whakaari with a proper understanding of the volcanic environment, he said.
"The only way to eliminate the risk of a volcanic eruption during a tour to Whakaari that could cause injury or death would be to not take tours to Whakaari at all. This is because... Whakaari is an active volcano which can erupt with no warning," he said.
"I've seen no evidence that the operators considered this option when establishing their businesses or at any point thereafter."
White Island Tours should have stopped the tours when it bought the business, but did not, he said.
"This is the clearest example I have seen of the absence of an effective risk assessment to determine if the level of risk involved in entering or remaining in a business activity is acceptable."
Peace said tourists were told to seek shelter if an eruption occurred, and listen to their guide.
He said the tour operators did not seek advice from GNS Science about the risks, including pyroclastic flows - dense fast moving flows of lava, volcanic ash and hot gas.
"Anyone caught in a pyroclastic flow or surge on Whakaari might be killed or seriously injured by burns or impact by ballistic ejector despite sheltering behind mounds or accessing the shipping container," he said.
"The time for a worker or tourist to take shelter on Whakaari when an eruption started was probably about 20 seconds."
The trial continues.