POLICE have advised motorists that the Cunningham Highway, which was blocked 30km west of Warwick due to a crash early yesterday, has now reopened.

Initial information indicates two trucks collided resulting in one of the trucks, which was carrying paint and chemicals, to roll over on the highway.

The road was closed for an extended period while crews cleaned up the spilt chemicals.

The speed limit has been reduced to 60 km/h.

Motorists faced more than an hour's worth of extra travel as a result of the closure. 

Both drivers were in a conscious state when emergency crews arrived on scene and were taken to Warwick Hospital with minor injuries. No other passengers were involved.

Warwick Police Senior Constable Clayton Binney said police were investigating "the usual causes" for the accident, such as weather conditions and speed.

He said police were planning on speaking to both drivers when they were able to.

Meanwhile, Queensland Fire and Rescue Service (QFRS) crews focused on cleaning up the paint, which contained an anti-fouling agent, used at the bottom of ships. Only when the contents were deemed safe could they remove the truck.

Until then a 400m exclusion zone was put in place, which caused bottle-necking traffic on the highway and even stopped trains from travelling along the nearby rail track.

While the highway remained closed, truck drivers were forced to go the round-about way via Millmerran or Stanthorpe, while smaller cars were asked to go through Pratten and Leyburn.

QFRS Inspector Eddie Lacko yesterday said fortunately, the paint was stored in 20 litre tins or smaller, instead of one large one.

"The contents could be harmful or fatal if inhaled or ingested," he said.

"Some of the contents are epoxy resins or hardeners."

Air samples recorded high levels of fumes within the immediate area of the truck.

Insp Lacko said crews had to wait for advice from environmental protection agency (EBA) and from a scientific department in Brisbane before they took action.

The truck, from company Joton Australia, was believed to be on its way from Melbourne to Brisbane.

Motorists are urged to call 13 19 40 for updates on highway closures.