FIRE investigators are working to find the cause of a spectacular truck fire which caused explosions heard across inner Gympie and Southside on Friday night.
The B-double fruit truck burst into flames on the Bruce Hwy, near Archery Park and Cross St about 7.44pm.
A quick thinking driver disconnected the two trailers from the prime mover and drove it to safety, one witness said.
Police said the truck was not carrying flammable or explosive cargo.
Traffic had to be diverted around the vehicle as huge flames leapt from the coupling between its two trailers.
Police left the scene about 9.40pm.
The sound of exploding trailer tyres was heard even across the Mary River at the Gympie Hockey Association club house in Power Rd.
Mayor Mick Curran said he heard the explosions from the deck of his Southside home and wondered who had the fireworks.
Closer in, one Lawrence St resident thought the noise was gun shots.