People have been ordered to evacuate from the site of a fiery crash after a semi-trailer carrying chemicals collided with a ute and exploded on a major highway.

An emergency alert was issued advising residents in an exclusion zone to “leave immediately” following the Bruce Highway crash at Bororen, 400 kilometres north of Brisbane, early on Friday.

Paramedics assessed the male ute driver for life-threatening injuries at the scene.

Bystanders pulled the male B-double semi-trailer driver from the truck.

He suffered abdominal, leg, pelvic, head and arm injuries and was flown by rescue helicopter to Bundaberg Hospital.

Emergency services remained at the scene battling fires involving both vehicles.

The truck spilled ammonium nitrate, a chemical commonly used in artificial fertilisers, sparking a 2.5-kilometre exclusion zone around the crash site.

Police took aerial footage that showed the rear trailer, carrying the larger quantity of chemicals, leaking onto the ground.

Shortly after the footage was taken, the trailer full of chemicals exploded.

“That explosion has possibly damaged part of the highway,” Queensland Ambulance Service’s acting senior operations Supervisor John Hodson-Gilmore said.

Police issued an emergency alert telling residents within the exclusion zone between Daisy Dell Road and Turkey Beach Road to evacuate due to the fire and chemicals.

“Residents within the exclusion zone are advised to Leave Immediately,” the alert said.

“If you cannot leave, shelter indoors, and close your windows and doors, and turn off your air conditioning.”

Queensland Fire and Emergency Service said it would be a “prolonged incident” as more than five crews attack the blaze and clean up the chemicals.

Motorists are warned it will be “quite some time” before the highway reopens due to the damage.

“There’s significant debris across the highway for approximately 50 metres onto the other side of the highway,” Hodson-Gilmore said.

“The Bruce Highway between Bororen and Tannum Sands will be closed to all traffic for quite an extended period of time.”

-AAP