A 29-year-old man who allegedly stole a semi-trailer and ploughed it through the main street of a country town in the NSW Hunter region will remain behind bars.
The driver of the alleged stolen truck, identified as 29-year-old Rod Johnson, was arrested at the scene and received hospital treatment for minor injuries.
Police have launched a critical incident investigation following this morning's truck crash.
A man has faced court on a string of charges after a "stolen" fertiliser truck crashed into a building at Singleton in the Hunter Valley, sparking explosions and a major rescue operation.
He was subjected to mandatory blood and urine tests, however was not charged with drug or alcohol-related offences.
A critical incident team from Port Stephens Local Area Command is investigating all circumstances surrounding the incident.
Police said the truck was sighted driving erratically south along the highway, through Muswellbrook and towards Singleton.
Police are examining if mental illness suffered by Rodney Johnson played a role.
They say road spikes were used in an attempt to stop the stolen semi-trailer once it reached Singleton.
The truck continued into George Street, where it caught fire after crashing into several vehicles and buildings, including one next to the Royal Hotel.
"I drove around the back streets to get around and saw a huge fireball and what looked like a auto transporter with cars all over the road", the witness said.
Despite the length of time they spent in the Australian bushland, an ambulance inspector said it was "really good" that they were in reasonable physical health after being in such a hostile environment. Three are being taken to hospital.