The Auckland company implicated in accidentally starting the SkyCity convention centre fire last year tried and failed to stop the release of the report into the blaze with an eleventh-hour letter from its lawyers.
The fire at SkyCity's New Zealand International Convention Centre broke out on the Level 7 roof on October 22, and burned for 10 days.
It led to large-scale disruption across the city, millions of dollars in damage and is considered one of the largest and most-difficult structure fires ever fought in New Zealand.
Fire and Emergency New Zealand released its report into the October 2019 fire on April 22 this year, which found the accidental ignition of cardboard inside a roll of waterproofing membrane was the most likely cause.
MPM Waterproofing had two workers on the roof that day, and video footage showed them working in the area where the fire broke out shortly after they left for lunch.
Immediately after the Fire and Emergency report was released, the company called for it to be withdrawn. And it can now be revealed the company had brought in lawyers to try to stop the release of the report in the first place, arguing that its workers had assured them they had removed the cardboard core from the roll of membrane before using torches.
The report suggested otherwise, saying it was likely the cardboard rolls were not removed, and smouldered for several minutes unnoticed, fanned by strong winds, before catching the waterproofing material alight.
A letter from barrister Greg Jones of Fortyeight Shortland, obtained by 1 NEWS under the Official Information Act, was sent to the fire service the night before the report was due to be released, calling for it to be withheld and accusing Fire and Emergency of "theatrics" when reconstructing the event.
Mr Jones wrote that his client "remains concerned about the findings", and that it was their view that a cardboard core would never have been left inside a roll of membrane during torching.
"As we understand it, both gentlemen working on the 7th floor have confirmed that cardboard was not present in the membrane roll at the time the work was carried out," Mr Jones wrote.
"All evidence points, in my client's view, to cardboard not being inside the membrane roll at the time the torch-on work was carried out."
MPM also took aim at the fire service's reconstruction of the ignition of the fire, which was carried out at a facility in Whenuapai.
Mr Jones wrote: "As I have previously indicated to you, my client regards the demonstration at Whenuapai as nothing short of theatrics.
"The method of torch-on application used involved an extravagant (wide) use of the torch in a manner that our client regards as unrealistic and intentionally carried out for the purpose of commencing the ignition."
He called the demonstration "inflammatory and misleading", saying MPM Waterproofing was "perhaps the most experienced torch-on applicator in New Zealand," and that "they have never experienced the ignition of a cardboard core in the manner that has been suggested started this fire".
"It would be impossible to count the number of rolls of membrane that would have been used by the staff in these circumstances, but it would literally be tens of thousands," Mr Jones wrote.
Mr Jones went on to ask Fire and Emergency NZ to withhold the report from public release.
"There can be no excuse for the publication of a report which is factually incorrect and sensationalises the cause of the fire in a way that MPM believes has occurred in this instance.
"MPM would be grateful if FENZ could refrain from publishing the report while these additional matters are aired between the relevant parties."
MPM Waterproofing had been provided with an embargoed copy of the report on April 20, two days before the scheduled release.
Fire and Emergency National Manager of Risk Reduction Roxanne Hilliard said the letter from MPM's lawyers was received about 11pm the night before the report was due to be released.
In a response letter sent to MPM's lawyer, also released under the OIA, Ms Hilliard said she had "in the time available" discussed the concerns put forward with the report's author - but still decided to release the report.
"We respect your client's right to take its own view of what the available facts mean, in terms of the cause and origin of this fire," Ms Hilliard wrote.
"For its part, Fire and Emergency remains comfortable with the view expressed in its report - we have accordingly decided not to adjust the time of the publication of the report."
Following publication of the report, MPM Waterproofing called for it to be retracted, which has so far not taken place.