Their parents Sharifi and Siamak Mosaferi fought for months to get a health and safety investigation.
The documents newly released under the Official Information Act show that WorkSafe was notified of the crash at 3.30pm on Good Friday.
A responder noted down: "A 6-year-old boy died at the scene."
This was Arteen Mosaferi, aged 4, not 6.
When the case was reactivated in January 2019, the triage record repeats this, and does not record that his brother, 2-month-old Radeen, had also died.
The responder on Good Friday, on the part of the form that asked what workplace was involved, wrote: "NA" [not applicable], though the trucking industry was involved.
Whose jurisdiction?
The fundamental decision that dictated what the family would go through for months to come, came four days later, on Tuesday after the Easter holiday break.
An inspector in Palmerston North emailed WorkSafe's notification centre to say he had been alerted to the crash "on the weekend".
"No follow up conducted on this one," he said in the one-line email.
WorkSafe's triage team, which sets priorities, then wrote: "NIA" meaning no immediate action.
They added: "Not WS jurisdiction".
This was despite the agency having jurisdiction under the Health and Safety at Work Act (HSWA).
The triagers then wrote: "File closed off."
In all, the triage report released by WorkSafe amounts to 21 words.
In the OIA request RNZ asked for all communications, but there is no record of any discussion taking place about the decision not to act.
WorkSafe chief executive Phil Parkes said in a statement to RNZ that the crash was "in police jurisdiction".
"No health and safety matters were raised by police with WorkSafe as a result of their work," said Parkes, who was chief operating officer at WorkSafe at the time.
The documents shed more light on this. They record a WorkSafe manager saying that while the two agencies had an agreement to discuss "whether there should be a HSWA investigation" by police, that did not happen.
The problem was, at the police end, its Commercial Vehicle Safety Team (CVST) handles HSWAs, but this team did not look into the Mosaferi-Sharifi crash "and hence this aspect was not considered".
The police crash report gives the qualifications of the Serious Crash Unit constable who investigated, and no health and safety qualifications are listed.
Parkes did not detail if WorkSafe had changed how it triages since the 2018 crash.
The police at this time had lost their health and safety investigation powers after HSWA was introduced in April 2016, and it took two years to fix that. Even now, with these powers restored, OIA figures show the police do not use HSWA much to investigate serious crashes.
WorkSafe historically has not investigated truck-related deaths unless police - the lead agency in any road fatality - asked it to, though the two agencies have an agreement that puts an obligation on them to ensure wider health and safety factors, such as supply-chain pressures on truck drivers, are looked into.
WorkSafe keeps no central record of how often police make such requests, according to an OIA response.
Up until this year the agency did not record truck-related fatalities as workplace deaths, even though transport and warehousing is the most dangerous industry sector.
'Moving heaven and earth'
The Desert Road file was eventually reopened in January 2019 after the family pressured WorkSafe's board.
Board chair Ross Wilson declined RNZ's request for an interview, and made no comment, instead backing his chief executive's statement praising the Mosaferi-Sharifi investigation.
The triage notes in January 2019 recorded only one victim, a 6-year-old boy, though investigators knew there were two child victims.
This omission occurs despite WorkSafe, by this stage, being in a state of agitation about the case, according to the documents.
In emails managers say the case was of "high public interest", there might be media scrutiny and "if the evidence is there, it is likely to be a prosecution".
A review of the police file and statements "should be a bare minimum to satisfy we have looked at the fatigue factor that is possibly alleged", the agency's Chief Inspector Steven Kelly wrote in mid-December.
He and others had already spent the December-Christmas period setting up an investigation team.
But they struggled for weeks - from late November to mid-January 2019 - to get hold of the police crash investigation report, which became the mainstay of their own inquiries.
"We are aware of tight timeframes and moving heaven and earth [to] do this justice," Kelly wrote on January 10, one day after the triage report recategorised the crash as "Category 1 - Workplace Investigation".
By then his team had just weeks left till the window to launch any prosecution closed, on March 30, 2019.
Normally, an HSWA investigation takes eight months, followed by four months of legal assessment over whether to lay charges, within a 12-month deadline.
On January 22, investigation manager Bruce Greathead made a plea to Head of Specialist Interventions Simon Humphries for help.
"At this stage it definitely looks as though we need to get involved," Greathead emailed.
"As the matter is now absolutely time critical, every day needs to be accounted for and planned.
"We have, in addition, obligations to report to Simon, who needs to report to the board and Nicole [Rosie, chief executive] on the matter as we will be under very close scrutiny.
"If there was ever a time where technology and IT could be gainfully used, this is it."
'Primary concern' is fatigue
Investigators' primary concern was "fatigue and hours the Dynes [Dynes Transport Tapanui] drivers are working", Kelly wrote around this time.
Greathead went further: "The police have conducted an investigation and have concluded that fatigue and fatigue management were significant factors in the accident."
However, months later WorkSafe told the family that fatigue had not been fully proved, so it did not prosecute.
WorkSafe twice declined to lay health and safety charges, though the Coroner gave it an extra six months to do so, and said it appeared there had been HSWA breaches.
The fatigue expert the agency called in had limited information to work with so late in the piece.
"The reliability with which anyone could recall [fatigue] information 10+ months after a serious crash is questionable," Professor Philippa Gander said.
She backed the truck company's approach to fatigue management.
The two Dynes drivers were convicted on careless driving, excessive work-hours and false logbook entry charges.
The police concluded John Barber failed to see traffic ahead slowing, and braked but hit the Toyota which had almost come to a stop.
The other trucker, Trevor Hall, was in front of the Toyota, and swerved into the oncoming lane of SH1 to avoid the slowing traffic.
Chilling still pictures in the police report taken by monitoring cameras looking out from Hall's truck show an oncoming car passing the truck just moments before it swerves out.
Hall told police in an "off the record" comment that he missed a required rest break because he was under delivery pressure, according to WorkSafe's investigation report.
However, when WorkSafe interviewed Hall, for the only time on February 26, 2019, 11 months after he crash, he denied telling police this.
The notes from that interview contain just 22 words related to work pressure.
At the time of the crash, on-truck technology was not being used to monitor the drivers in real time.
Barber refused to talk to WorkSafe and it did not use the powers under HSWA Section 168 to require him to.
The agency did not interview any other staff at Dynes "as our focus for this investigation was on the drivers", Humphries said.
Experienced industry players told RNZ this statement was at odds with a key aim of HSWA, which was to trace accountability beyond the worker, up to the executive and board level.
It would be little use targeting drivers who already faced road charges and who had the right not to incriminate themselves in interviews, they said.
The Transport Agency said there had been no audit of Dynes Transport since 2012, but after the crash a desktop assessment concluded the company was "generally compliant" with work-hour rules.
Dynes' lawyer said the company did not wish to make any comment.
'Full and thorough' investigation
WorkSafe repeated that its decision not to investigate, and only changing its mind nine months on, had no effect at all on the outcome.
It was a "full and thorough" investigation, it had told the Coroner earlier.
It was "thorough and professional", Parkes said in a statement to RNZ, backed by board chair Ross Wilson.
Parkes declined an interview.
He acknowledged that WorkSafe had said its first contact with the Mosaferi-Sharifi family was in December 2018, when in fact it was before October 2018.
"However, the points you [RNZ] raise did not have a substantive effect on the outcome," Parkes said.
"We have noted to you in the past that WorkSafe today is a different organisation than it was during the time of the incidents you are raising with us.
"We have learned from our past performance and have developed new and improved ways of working."
WorkSafe had provided "very extensive information" and comment on it to RNZ about the crash, and "we regard this issue now as closed", it said.
29 risks and opportunities identified
An OIA document from May 2019, prepared for Parkes as COO, lists a slew of investigative weaknesses identified in 2018.
That included gaps in "investigation of precursor events".
Lawyers, unions and researchers have previously criticised the agency for not investigating the upstream supply-chain pressures that contribute to truck crashes. The agency this year began research into this.
The 2019 gaps report also identified "limited use of insights and intelligence", lack of "capacity to audit processes and systems" and lack of specialist staff training.
"Without additional investment and with 29 risks and opportunities identified to date, Operations' ability to deliver on WorkSafe strategy will be significantly negatively affected," Parkes told the board.
A month later, in mid-2019, the agency received an independent report into investigation shortcomings. It made this public a year later after an RNZ OIA request.
It then set out to spend $5 million to improve investigations.
Shortly after, a year ago, WorkSafe began its largest investigation ever, into the Whakaari/White Island disaster which killed 22 people. At peak the agency had 28 staff working on Whakaari, including drawing from a pool of about 40-50 investigators.
"Inevitably when we have an investigation of this size and complex[ity], we've had to redeploy resources from elsewhere but we've sought to balance the importance of this investigation with doing our other work," Parkes said.
"I've got every confidence that both this investigation and our other investigations are being done thoroughly and professionally."
