A sixth person is confirmed dead as rescue efforts have given way to a grim recovery operation two days after a volcano erupted at a popular tourism site in New Zealand. Monday’s volcanic blast left 30 injured and eight missing and presumed dead, prompting calls for investigation into the safety of tourism at New Zealand’s most active volcano.

New Zealand Police confirmed Tuesday that an injured victim taken from White Island, also known as Whakaari, died at a hospital in suburban Auckland that night, bringing the death toll to six, The Australian reports. Officials warned Tuesday night that positively identifying the deceased could take time owing to the “severe” nature of the injuries suffered.

“The scale of this tragedy is devastating,” New Zealand Prime Minister Jacinda Ardern said during an address to Parliament Tuesday in which she updated the public and took the opportunity to praise helicopter crews who landed on the island to rescue survivors. “Police and defense force personnel have taken a number of aerial reconnaissance flights over the island since the eruption. However, no signs of life have been detected."

Police now believe that 47 visitors were on the island when it erupted at 2:11 p.m. local time Monday and launched thick clouds of ash 12,000 feet into the air leaving some survivors with severe burns. Half of the visitors are Australian, while nine of them are Americans, police said; other visitors on the island were from New Zealand, China, Germany, Malaysia and the United Kingdom. Several of the visitors were passengers from a Royal Caribbean cruise ship in port at Tauranga, a coastal town about 55 miles from White Island.

Windy conditions on the island, and the fact that minor volcanic eruption activity is still taking place, have slowed recovery and analysis efforts even as scientists forecast that the most violent eruption has passed for now. Police said they plan to fly drones carrying equipment to test gas levels, though crews were largely kept off the Island on Tuesday.

“Moderate volcanic unrest continues at Whakaari/White Island, with substantial gas, steam and mud bursts observed at the vent located at the back of the crater lake. Other monitoring parameters remain elevated and the Volcanic Alert Level stays at Level 2,” a Dec. 3 bulletin read.

But signs of unrest in the days before the volcano eruption have led to questions as to why tourists were able to access the uninhabited island whose bursts of “explosive gas and steam-driven mud jetting” from the volcano’s vent, according to GeoNet, had been intensifying in recent weeks.

Barbara Barham at first didn’t foresee trouble when her newlywed daughter, Lauren Urey, 32, called from her honeymoon aboard the Royal Caribbean cruise ship to report that she and her husband, Matthew, were docked in New Zealand and headed to an action-packed day on the island.

“She said they were going to the volcano,” Barham told The Washington Post. “My husband was joking around and said, ‘I hope it’s not a live volcano.’”

But after a midnight call from Royal Caribbean telling Barham that her daughter and son-in-law had not returned to the ship, Barham received an even more troubling call from Matthew’s mother; she had received a distressing voice mail from her son.

“Her son called and said that they had been on the excursion and there had been a volcano eruption and they were burned very bad,” Barham recalled. “He said he would try to call as soon as he could, but talking and making phone calls was difficult. His hands were so badly burned, it was hard for him to make a phone call.”

After hearing reports of the volcano’s ongoing activity in the days before her children visited. Barham told The Post she was “livid.”

“There’s been warnings about it. … My son-in-law never would have booked the excursion if he knew there was any chance of them being injured.”

Barham’s daughter and son-in-law remain hospitalized with severe burns.

Although White Island last had a “short-lived eruption” in April 2016 and spewed ash from a vent five months later, Monday’s eruption was surprising but not unique, according to scientist Ken Gledhill of GeoNet.

“In the scheme of things, for volcanic eruptions, it is not large,” he told the Associated Press. “But if you were close to that, it is not good.”

Tour operators make the ultimate decision whether to take visitors to the privately owned island, where access is controlled through permits, the New Zealand Herald reported.

Prime Minister Arden acknowledged in her remarks to Parliament Tuesday that “there will be bigger questions in relation to this event” but did not detail who or what entities investigators may scrutinize.

New Zealand Police later Tuesday backed off a previous statement that the deaths and injuries would be investigated as a criminal matter.

“It is too early to confirm whether there will also be a criminal investigation,” police said in an updated statement. Police, working on behalf of the coroner, would investigate in coordinating with WorkSafe New Zealand, which regulates workplace health and safety conditions in the island nation.

“WorkSafe New Zealand has opened a health and safety investigation into the harm and loss of life caused by the eruption,” the agency said in a statement via Twitter Tuesday. “As the workplace health and safety regulator and administrator of the Adventure Activities Regulations, WorkSafe will be investigating and considering all of the relevant work health and safety issues surrounding this tragic event.”

Royal Caribbean Cruises said in a statement that the company is “devastated.”

“We are working together with local authorities, and we are providing all the help and care we can to our guests and their families, including offering medical resources and counseling,” the company said.

Royal Caribbean is sending staff from the ship and its Sydney and Auckland offices to help family members. Ovation of the Seas will remain in port for the time being, the company said.

Deanna Paul contributed reporting.

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