The prime mover veered off the Mitchell Highway in south west Queensland just before 9pm on September 5 that year and rolled, leading to two powerful explosions.

The truck driver and a bystander who tried to help him suffered severe injuries, including serious burns, while four firefighters, a police officer and another bystander were also injured.

The government launched a lawsuit in the Brisbane Supreme Court claiming more than $7.8 million in damages, the estimated cost of building a temporary detour, and inspected the area to ensure it was safe as well as replacing the road and railway bridge.

It is holding the trucking company, Kalari Proprietary Limited, road train driver Anthony David Eden and insurer Dornoch Limited responsible for the repair bill.

Mr Eden, a truck driver with 17 years' experience, was travelling south along the Mitchell Highway near Wyandra, between Charleville and Cunnamulla, at the helm of the truck, which was hauling three trailers.

He had completed the trip from Gladstone to South Australia carrying ammonium nitrate on an almost weekly basis during the 13 months prior to the crash and explosion, without incident.

The road train was carrying about 52.8 tonnes of ammonium nitrate, bound for a mine in South Australia to be used to make bulk explosives.

According to court documents, the prime mover caught fire about 9.50pm and Mr Eden steered off the highway, causing it to hit a guard rail near the Angellala Creek Bridge and roll onto its side in the dry creek bed.

The crash led to two explosions occurring at 10.11pm and 10.12pm. They were so powerful Geoscience Australia recorded a magnitude 2.0 earthquake and one of the railway bridge spans was thrown 20 metres through the air.

Police officers said they saw a "large fireball illuminate the sky in front" and about three seconds later they heard a "loud explosion" and felt a "shockwave" in their vehicle.

In its statement of claim, the government alleges Mr Eden had started work before 8am and had been driving for more than 12 hours.

By law, he should take at least an hour break during a 12-hour shift but government alleges he did not.

In doing so, the government claims, Mr Eden should be held liable for “failing to exercise the degree of care and attention that would have enabled him to observe the fire sooner and bring the road train safely to a stop”.

The trucking company has also been accused of failing to train Mr Eden in the proper response to vehicle fires, of making the wrong decision by using trailers made from aluminium for transporting the ammonium nitrate and of not properly maintaining vehicles and equipment.

Mr Eden has not been held solely responsible for the fire outbreak, with the most likely cause identified by investigators as a mechanical fault, such as an overheating tyre.

In response, the defendants point out the police report did not identify a definitive reason for the truck veering off the highway and did not conclude fatigue was a factor.

Mr Eden said the flames started at front of the vehicle in front of the windscreen and he considered the safest action to take was to steer off the roadway.

The defendants argue Workplace Health and Safety Queensland investigations did not identify any breaches in terms of driver training or vehicle maintenance.

Meanwhile, a Department of Natural Resources, Mines and Energy investigation found vehicle maintenance was not an issue as it was regularly maintained.

The DNR could not determine what caused the initial fire due to key evidence being destroyed in the explosion and resulting fire.

The matter will return to the Brisbane Supreme Court on January 16.

Brisbane Times