The trusses and studs of the verandah had smashed through the top of the cab and a big steel girder was in the passenger seat.
Once the driver was removed, a firefighter performed CPR on him but he died a short time later in an ambulance.
Mr Carter said there was potential for an explosion as the truck was carrying pressurised cylinders of oxygen, acetylene and LPG.
"We checked the vehicle and found a couple of the cylinders had worked themselves loose and fallen over."
The fear was that some of the valves had broken off but none were damaged in the crash.
Until they established the cylinders were intact, there were some anxious moments because the wooden RSA building was tinder dry.
The trailer unit was full of electrical apparatus and plastic piping. Diversions were in place around the accident scene for several hours but State Highway 1 was reopened by 9am.