A truck carrying more than 40 tonnes of chemicals has exploded, with the shock waves felt kilometres away, after a fatal crash closed a major highway.
The male driver of a ute died in the fiery head-on collision with a B-double semi-trailer on the Bruce Highway, near Bororen in central Queensland, early on Friday.
The truck was carrying 42.5 tonnes of ammonium nitrate, a chemical commonly used in fertilisers.
The crash, which occurred just after 5am, sparked an emergency alert, with residents within a 2.5km exclusion zone told to leave immediately.
About 49 people evacuated to the nearby town of Bororen after police doorknocked the area.
Just after 9.30am, about four hours after the crash, the truck exploded, producing a blast radius of 500m.
No-one was injured or any property damaged but the eruption was heard and felt kilometres away, sending shock waves through the area, north of Miriam Vale.
Power lines were downed and several spot fires sparked.
"A blast was heard and felt and there was a visible large cloud of smoke," Queensland Police Mackay District Officer Acting Superintendent Mark Burgess told reporters.
Queensland Fire Department Superintendent Brad Stockwell said ammonium nitrate was normally stable.
"It's always stable to be transported," he told reporters.
"However once it was involved in a vehicle accident and an impending fire heated up one of the vessels, and then the pressure vessel, in time, unfortunately exploded."
An exclusion zone between Daisy Dell Road and Turkey Beach Road that had been in place since the crash was lifted late Friday afternoon.
"The focus now is to render the broader area safe and return residents to their homes at the first opportunity," Supt Burgess said.
He said the scene had been declared safe for first responders and there was no immediate concern for public safety.
However the investigation into the crash and clearing the scene would take time.
Emergency services continued to extinguish spot fires in the area.
Diversion routes were set up, with the section of the Bruce Highway expected to be closed for some time.
Gladstone Mayor Matt Burnett told NewsCorp the section of the Bruce Highway - the major arterial road from Brisbane to the north - could be shut for days due to the clean-up required.
"That explosion has possibly damaged part of the highway," Queensland Ambulance Service Acting Senior Operations Supervisor John Hodson-Gilmore earlier told reporters.
"There's significant debris across the highway for approximately 50 metres onto the other side.
"The Bruce Highway between Bororen and Tannum Sands will be closed to all traffic for quite an extended period."
The Queensland Fire Department was also running scientific testing including an atmospheric assessment of the area.
Queensland Rail service between Bororen and Iveragh - spanning 30km - has also been impacted, with buses organised for affected customers.
The B-double driver was airlifted to Bundaberg Hospital after bystanders pulled him from the vehicle.
He suffered abdominal, leg, pelvic, head and arm injuries but was reportedly in a stable condition.
It marks the third major crash involving trucks in the same region on the Bruce Highway this week.
