Whakaari/White Island was smothered in grey, on December 9, 2019.
A super-heated, highly-acidic eruption tore across the crater without warning.
Ash concealed huge landmarks - helicopter landing pads, an old sulphur factory and a shipping container.
Eight adventurers died on the submarine volcano. Another 16 would later succumb to horrific burns, inhalation and blast injuries. And 25 survivors were left with lifelong physical and mental recoveries from the explosion.
Despite tourist companies leading visitors on to New Zealand's most active volcano for decades, some stakeholders' health and safety obligations were unclear.
RNZ can now reveal the confusion went right to the top.
Documents obtained under the Official Information Act show leading up to the eruption, Local Government Minister Nanaia Mahuta's public safety responsibilities were ill-defined, and still are.
Whakaari's distance offshore means it does not come under the authority of any city or district council.
As minister since 2017, Mahuta has automatically been the territorial authority for 11 offshore islands such as Whakaari/White Island, Mōtītī Island and Tūhua (Mayor Island).
Department of Internal Affairs staff have spent months reviewing her health and safety, civil defence and emergency management duties for Whakaari.
They have now told her: "It is not clear in the legislation how your role as Territorial Authority is intended to work in practice."
That's despite a Memorandum of Understanding the Government signed with the Bay of Plenty Civil Defence Emergency Management Group four years ago, to determine "responsibilities for the island".
'Our system puts this stuff off'
RNZ approached Sir Peter Gluckman for comment - who was the Prime Minister's Chief Science Advisor until mid-2018.
He said the ambiguity surrounding Whakaari alludes to "significant deficiencies" in risk management across government in New Zealand.
Gluckman, who now heads the University of Auckland's Koi Tū think tank, said "thinking about risk properly - stewarding our human, environmental and economic assets - is the first obligation of government".
"And at the moment, I think the many officials I talk to would agree that our system puts this stuff off."
In his view: "It's very easy for it [risk management] to become siloed, in ways that mean that nobody is sure who has accountability for what."
To clarify accountability for Whakaari, the Department of Internal Affairs is now reviewing its memorandum with the Bay of Plenty Civil Defence Emergency Management Group.
But older documents held by RNZ show the island has also caused uncertainty further down the chain.
Minutes of Eastern Bay of Plenty Emergency Services Coordinating Committee meetings in 2015 show emergency services faced difficulties getting a shelter with first-aid stores put on the island, because the Department of Internal Affairs was "supposed to take responsibility".
Minutes from 2016 cited "concern" about risk management duties on the island, and police discussed the need for a rescue exercise on the volcano for six years leading up to the eruption but it was never followed through.
Meanwhile, the Bay of Plenty Civil Defence and Emergency Management Group was yet to finish its own plan for a response to an eruption at Whakaari when the vents blew.
The "Search and Rescue Plan" section was two sentences long, simply stating that police would lead any rescue operation.
The rest of the 25-page document covered the group's internal roles and responsibilities.
The need for an inquiry
These records do not sit well with Nigel Hampton QC - one of New Zealand's most experienced defence lawyers - who is a health and safety law specialist.
"It's easy now for one agency to point the finger at another and say, well, we thought you were looking after it."
Hampton said public services showed similar confusion after the Pike River Mine disaster and CTV building collapse more than a decade ago.
"But nobody, nobody, nobody seems to have applied their mind to such things."
Hampton and fellow law experts, Hugh Rennie QC and University of Canterbury professor John Hopkins, have argued that government departments have not, and will not, properly examine any of their own possible failings leading up to the tragedy.
They say a public inquiry is urgently needed, as does the National Party.
But officials have advised ministers against an inquiry for now, citing possible overlaps with investigations by police on behalf of the Coroner, and by WorkSafe.
Department of Internal Affairs emails show, a week after the eruption, staff preparing statements for former minister Tracey Martin wrote: "If we cannot use the inquiry word at all that would be best."
They also acknowledged the department could itself be included in the scope of such a probe.
If held, an inquiry could also steer decision-making on the future of tourism at Whakaari.
Pre-eruption, operators were taking up to 20,000 people onto the crater a year, often charging hundreds of dollars a head.
Determining volcanic risk
In University of Canterbury disaster risk professor Tom Wilson's opinion, the Department of Conservation's protocols at Tongariro National Park are "really good examples" of volcanic risk management that have led to "some success".
DoC's procedures hit headlines last year when they were compared to those at Whakaari.
Government correspondence showed "no one would have been permitted on the island [Whakaari]" at volcanic alert level 2 in December 2019, if DoC had control of the privately-owned island.
Wilson said "assessing volcanic risk is very difficult at the best of times".
"It's almost impossible to robustly forecast it, even with the very best expertise and equipment, which is what we have in New Zealand with an absolutely world-class team."
But some of that team of volcanologists are Crown researchers at GNS Science, one of the 13 parties now facing WorkSafe prosecution for alleged breaches of health and safety law.
None of the 13 has entered pleas yet and, if convicted, they face fines of up to $1.5 million plus possible reparation payments.
The accused include the Government's National Emergency Management Agency, and members of the Buttle family, who own the island.
There are also four tourism ventures charged, including White Island Tours and Volcanic Air who had tour groups caught in the deathly surge.
The Government has said the most contentious aspect of future access to Whakaari is whether tour companies like these will bring sightseers onto the island again.
While the roles, responsibilities and rights of stakeholders at the island remain cloudy, it is unlikely these operators will have any clarity.
WorkSafe's prosecution, the police investigation and government department reviews are ongoing.
How these probes will change human interactions with New Zealand volcanoes remains to be seen.
Local Government Minister Nanaia Mahuta declined to be interviewed by RNZ about Whakaari. In a statement she said, with tour visits onto the island on hold, her involvement was limited.
Police said national and district debriefs had been held after the eruption, with "commitment to continuous improvement".
A statement from the Department of the Prime Minister and Cabinet said "agencies work together closely" to minimise hazard risks and impacts in New Zealand, with "tools to help to identify potential gaps and opportunities".
WorkSafe declined to comment while investigations were ongoing.