Police believe a leaking gas canister caused an explosion in a south Canberra primary school car park, killing a father described as a "down-to-earth, good bloke".
A 51-year-old man died in Canberra Hospital after being injured by the explosion, which happened in a white ute at St Clare of Assisi Primary School in Conder on Thursday afternoon.
ACT Policing said the incident was not being treated as suspicious.
School principal Matthew Egan-Richards said the man had just arrived to pick up his child from an after-school care program when the explosion happened about 4.55pm.
He described the man, whose name has not been released, as an active and well-liked member of the local and school communities.
"He was a down-to-earth, good bloke [from a] lovely family [who are] very supportive of the school and very involved in their community," Mr Egan-Richards said.
"I have had contact with the family, and of course, it’s tough. It’s very, very tough.
"... [It has been] a tremendous shock and heartache for them."
A visibly shattered Mr Egan-Richards addressed the media on Friday morning after just a few hours' sleep, saying that staff were spending the day arranging support for children and their families.
He said counsellors would be at the school when it reopened on Monday to talk to the children, parents and staff who have been devastated by the incident.
Mr Egan-Richards said children were at the after-school program when the explosion happened, but he did not believe any children had witnessed it.
"I felt sick. It's horrible," Mr Egan-Richards said when asked how he had reacted to news of the man's death.
"It’s a very close and tight-knit community in the Lanyon Valley, and they will pull together and support each other.
"We will work together and look at what we need to do to provide any support that’s required."
Mr Egan-Richards said he did not want to say how many children the man had at the school, in order to protect the privacy of his family.
WorkSafe ACT confirmed it was also investigating the blast as the car involved was a work vechicle but could not yet comment on the nature of the incident or the canister involved.
Crews had worked overnight at the scene alongside police, a spokeswoman said.
"Our thoughts are with the friends, family and colleagues impacted by the death last night," she said.
The school community rallied quickly after the explosion, with messages of support pouring in online and some families visiting the school on Friday morning.
Shortly before 9am, a family with two young children left a floral tribute and a folded note at the school gates, minutes before two car loads of detectives arrived.
Four teachers stood outside the school at drop-off time to inform parents who were not aware of the incident that the school was closed on Friday.
Dozens of uniformed and forensics officers spent Thursday night and early Friday morning gathering evidence and guarding the car park, which was cordoned off.
The white ute remained visible in the car park on Friday morning as investigators examined the scene.
There were no scorch marks or other visible signs of fire, but the blast had left part of the right-hand side of the ute hanging off.
ACT Policing said it would prepare a report for the coroner with help from WorkSafe ACT.
Anyone with information on the explosion is urged to contact Crime Stoppers on 1800 333 000, or via the Crime Stoppers ACT website.
Information can be provided anonymously, quoting reference number P1674490.