New Zealand’s navy lost its first ship since World War II after the HMNZS Manawanui sank on a reef off the coast of Samoa on Sunday creating a potential environmental disaster in waters used for fishing and tourism.

The specialist dive and hydrographic vessel lost power and ran aground on Saturday evening while conducting a reef survey one nautical mile off the southern coast of the Samoan island of Upolo, according to New Zealand authorities.

By Sunday morning, the vessel was “listing heavily,” the navy said. Smoke was spotted around 6:40 a.m., and by 9 a.m. the ship had slipped below the surface.

It’s the first unintentional sinking of a New Zealand naval vessel since the Second World War, authorities said, as they opened a court of inquiry into what happened.

Local businesses and conservationists now fear the potential environmental impact of the accident, which occurred in waters off Samoa’s most populated island.

New Zealand Defense Minister Judith Collins told Newstalk ZB that authorities’ first priority was assessing the depth of the vessel and the risk of a spill.

“It’s got a lot of oil on board. …. It’s got lubricating oil, hydro oil, diesel, urea. It’s got a lot of stuff in it. And I don’t think we can just sort of leave it like that,” she said.

Divers were sent to the scene on Sunday night, she said. “They’ll be having a look to see what they can, but it’s going to be quite a big job,” she added.

Acting Samoan Prime Minister Tuala Tevaga Iosefo Ponifasio said in a press statement Sunday that an oil spill was highly probable.

“The HMNZS Manawanui is not recoverable and has sunk into the ocean,” he said.

A reef emergency

Samoan police received a distress call just before 7 p.m. on Saturday night, according to local authorities. Small boats were dispatched with the warning that the ship was taking on water and its crew would likely need evacuating.

Numerous vessels and aircraft were sent to help, including a Royal New Zealand Air Force P-8A Poseidon and C-130J aircraft, the New Zealand navy said.

By 5 a.m. Sunday, all 75 passengers and crew had been rescued, but witnesses said they soon saw smoke rising from the sinking wreck.

“It took 15 minutes for the boat to be fully ablaze and then sink,” he said, adding that local villagers left a Sunday church service to watch the ship.

“They were visibly upset and concerned for their beach, reef, marine reserve and income as fishermen,” Poole said.

New Zealand Prime Minister Chris Luxon said that “environmental spill kits” had been sent from New Zealand to help mitigate and minimize the effects.

The HMNZS Manawanui was a relatively new addition to the New Zealand navy, having been purchased in 2018 for around $100 million NZD ($61 million), though it was built in the early 2000s.

According to the navy, the ship was designed to “survey harbours and approaches prior to larger support ships landing support equipment and personnel whether for combat or disaster relief.”