Northland locals say they've been raising concerns about oil leaks from the Niagara shipwreck for decades, but have been "fobbed off" by authorities.
A Newshub Nation investigation revealed the Government is now reassessing the risk of a major spill from the war-time wreck, which lies off the coast of Whangārei.
Associate Transport Minister Julie Anne Genter says she has asked officials to do a thorough desktop analysis to determine whether further on-site surveys or extraction of the oil is required.
Maritime NZ is due to report back in August and it will likely be up to Green co-leader James Shaw to decide the next step, as he takes over Ms Genter's Associate Transport portfolio while she's on maternity leave.
Renowned diver and environmentalist Wade Doak has been trying to warn authorities about the wreck for nearly 20 years.
"It's very near to islands like the Poor Knights, the Hen and Chicks, Little Barrier - which I call the 'Green Te Papa' because it has so many natural treasures. All of them would be at risk from a spill, as would the Whangārei Harbour," he says.
"Marsden Point [Oil Refinery] does have some capacity to respond to oil spills - but from what I understand they can only handle about six tonnes of oil in good conditions."
It's believed there could be more than 1000 tonnes of oil in the wreck's intact tanks, which are expected to corrode and collapse in the next decade.
Finn Cook from Whangārei-based Fah Out Fishing says the slick above the wreck has become near-permanent over the last four years.
"We see it every time we go out there, and on a calm day you can see bubbles of oil the size of golf balls rising to the surface," he told Newshub Nation.
"It stinks out there, like it's hard to describe the smell, but it's like rotting - the oil is rotten and the slick leaves these scum lines on your boat.
"I have rung the council many times and they say it's got nothing to do with them and start playing the blame game and make it someone else's problem. It's just this huge run-around and a complete waste of time."
The wreck is in the Auckland Maritime Region but a spokesperson for the Auckland Harbourmaster says Maritime NZ is responsible if there's a major spill.
Maritime NZ says the wreck lies "below one of New Zealand's busiest shipping routes and small leaks are reported by the many vessels that use the area".
Marine Pollution Response Service Manager, Renny van der Velde says the agency always follows up the reports.
"All the small spills from Niagara in recent years have been found to have naturally dispersed, with no observed environmental impact," says Mr van der Velde.
"In the event of an oil spill in New Zealand waters there are regional plans for each area, and a national plan and 22 caches of oil recovery equipment to support the regions."
Despite Maritime NZ's assurances, a grassroots movement has been gaining momentum over the past year, calling for a survey of the Niagara to find out exactly how much oil is on board.
The Northland and Auckland Conservation Boards raised their concerns with former Transport Minister Simon Bridges in 2017.
In a letter, he replied that the official advice from Maritime NZ was that any remaining oil would likely have solidified by now, due to the cooler temperatures at the wreck site.
Frustrated at the official response, Mangawhai artist Nicki Everett held an exhibition in February 2018, called Gold and Oil, to highlight the danger to her community. More than 1500 people passed through in just two weeks.
"So many people had absolutely no idea, even those born and raised in Mangawhai," she says.
Ms Everett and other local residents have set up petitioning campaigns calling on MPs and other local politicians to take action.
It's a cause that's been taken up by Auckland Councillor and Hauraki Gulf conservationist Mike Lee.
He says the shipwreck presents a "growing danger", and official advice is downplaying the risk of a major spill.
"If officials from the likes of Maritime NZ are to have the final word, why should the people vote for politicians?
"Politicians are elected for the very purpose of fixing problems the bureaucrats won't - like the Niagara."
Mr Lee says it's a test for the Green Party in particular, as Conservation Minister Eugenie Sage and Associate Transport Minister Julie Anne Genter are in charge of the wreck.
"My advice to Ministers Sage and Genter is to listen to their better angels - and take action," he says.
How much oil is still on the Niagara?
The Niagara's tanks were capable of holding 4324 tonnes of oil. Due to the war, there is no known record about how much fuel was loaded onto the ship in Auckland.
However, the luxury liner was heading to North America when she sunk and Keith Gordon, author of Deep Water Gold: The story of RMS Niagara, believes there would have been at least 3000 tonnes of oil on board.
"After the Niagara went down the old records show that the beaches like Ocean Beach [in Whangārei Heads] were thick with oil and it did a lot of damage," he says.
Newspaper reports from the time reveal a black tide coated the Northland coastline in heavy bunker oil, up to 7.5cm thick.
Taking into account the slow leaking since the ship went down, as well as the larger spills during the sinking and gold salvage operations, Mr Gordon estimates there may be 1000 to 1600 tonnes of oil remaining in the ship's hull.
What have officials been doing about the Niagara?
Mr Gordon first wrote to the Ministry of Transport about his concerns over the Niagara in October 1991, but according to correspondence released under the Official Information Act, it wasn't until January 2000 that the Maritime Safety Authority (MSA) started taking the threat seriously.
A big summer storm had stirred up the seafloor, causing a significant spill and oil slick above the wreck.
Officials at the time observed: "[There was] some damage to the flora and fauna [on the Poor Knights Islands]. This spill served as an indicator to the likely damage should a large spill occur in this area."
An investigation was launched, with the MSA requesting a quote from Sydney-based company, United Salvage, about the cost and difficulty of surveying the wreck and removing any remaining oil.
United Salvage replied: "given the location and depth - it is not going to be cheap", but said putting together an exact figure would be misleading.
Within a month, the MSA had decided the wreck wasn't a threat. Minutes from a meeting in February 2000 recorded that: "given the type of oil and the depth of the water the wreck lies in, the risk of a major oil leak is very remote."
It put together an official response strategy which recommended the site should continue to be monitored, but "no salvage/oil recovery attempts should be undertaken".
A few months later, in April, the Navy conducted a sonar scan of the wreck to determine its exact position.
But in June of that same year, the Northland Regional Council - which had been recording oil slicks above the wreck since at-least 1989 - requested the Navy conduct another on-site survey of the wreck to determine how much fuel remained onboard.
The Marine Safety Authority confirmed the Navy was willing to assist and that the HMNZS Wakakura would use sonar equipment to scan the wreck in late October 2000, and the HMNZS Manawanui would film the wreck using Remote Operated Vehicles (ROVs) in early November.
The results of these Navy surveys are unclear. When Newshub Nation asked for the results, a spokesperson for Maritime NZ said: "despite reasonable efforts to locate the information, the information you're requesting cannot be found".
In 2001 and 2004 the Niagara was mentioned as being a high risk in the MSA's strategic plan, but no action was taken.
In February 2008, another large summer storm caused a significant spill, prompting Maritime NZ officials to inform then-Transport Minister Annette King.
A local boatie said in an email to the agency: "The slick was clearly visible in heavy seas running east for as far as one could see."
"I have been over the vessel for years and would put this as by far the largest release I have ever seen."
"Unlike previously, a lot of the oil is in blobs and the slick is far wider and thicker than I have seen. It quickly covered the hull and flattened the sea for a radius of about 200-300m."
The potential danger posed by the wreck took senior officials at Maritime NZ by surprise, with the deputy director at the time writing in an email: "Surprisingly, although I have been at MNZ for some time I was not aware of this wreck."
A sample of the oil was taken and Flinders Cook Technical Services, which did the analysis, advised that the fuel appeared to have a high pour point, meaning it flowed more easily when warmed.
"This may be the reason for its appearance coinciding with the warmest sea conditions," it said in its report.
The 2008 slick was measured as 7km long and lasted for two weeks. Another slick was reported in March 2009.
However, the Niagara soon faded from memory once again, until the Rena disaster in 2011. Media reports from the time, including a piece from TV3's Campbell Live, highlighted the danger posed by the Niagara's decaying wreck.
In 2014, the Department of Conservation raised concerns with Maritime NZ officials about the potential of a catastrophic oil spill, which would badly impact seabirds and other native wildlife on the surrounding islands and coastline.
Maritime NZ reported back that it was still following the response strategy from the early 2000s but admitted: "While the document does provide Maritime NZ with some guidance, it is now 14 years old and much of it is out of date."
In 2016, Maritime NZ updated its Niagara response strategy. The review confirmed a major spill from the wreck would be considered a tier three event, which could require international assistance.
"Tier 3 oil spills are generally more complex, of longer duration and higher impact, and beyond the response capability of the regional council or operator," says Mr van der Velde.
"The response is nationally led and coordinated by the National On-Scene Commander for Maritime NZ, which will likely call on considerable resources from around the country and overseas."
The National Oil Spill Contingency Plan, plus four regional plans, will now apply for any oil spills from the Niagara.
"All of these plans... collectively cover the risks, threats, and response options for any spill from any source in the Hauraki Gulf," says Mr van der Velde. "Including the wreck of the Niagara."