A 29-year-old man faced court on several charges on Thursday after allegedly causing widespread damage, by stealing a semi-trailer and leading police on a 100km chase, ending in a fireball in the town of Singleton.
Rodney Johnson has been refused bail, with his lawyer asking for a mental health assessment.
And the actions of police are also under scrutiny, after officers deployed road spikes 3km outside the town, in a bid to halt the runaway truck.
Horrified residents of the quiet Hunter Valley town ran for their lives when a truck packed with fertiliser sped through the streets before crashing and creating a fireball around 9am on Wednesday.
Police were initially alerted about a semi-trailer that was stolen from a petrol station in Murrurundi, north of Singleton. The semi trailer was then seen allegedly driving erratically on the New England Highway, towards Singleton.
Police didn't start a pursuit but put road blocks up in a bid to stop the driver.
He then allegedly hit the spikes but continued up the main road of Singleton, smashed into four vehicles and a building, leaving several people with several injuries.
NSW Police said in a statement that a critical incident team from another region would be brought in to investigate "all circumstances" surrounding the incident, including police actions.
"That investigation will be subject to independent review," the statement read.
On Thursday, a 67-year-old man remains in hospital with serious injuries, including head and chest injuries; he was in one of the cars that was hit by the semi-trailer.
An elderly couple in their 60s was also taken to hospital, the woman with pelvic and hip injuries and the man with neck and chest pain. They are both in a stable condition.
Others suffered minor injuries.
One witness told Nine News he saw masses of black smoke in the air.
"I drove around the back streets to get around and saw a huge fireball and what looked like a car transporter with cars all over the road," said the witness.
Singleton Mayor Sue Moore has told the ABC the town "looks like a war zone".
"I can sympathise with the people that are actually involved with the situation," Moore said.
Rodney Johnson, 29, was taken into custody and charged with several offences including police pursuit, stealing a motor vehicle, and malicious damage. He has also been charged with resisting arrest, assault of a police officer and using an "offensive" weapon to prevent arrest.