A Ford cube truck ran into the back of a tractor-trailer that had stopped on the eastbound Gardiner Expressway this morning, a crash that caused delays for drivers for hours.

The collision occurred in the south curb lane of the eastbound express lanes, west of Islington Avenue. Toronto police were called to the scene at 8:14 a.m.

Police say the tractor-trailer had been "loaded with over-length steel girders," one of which penetrated the cab portion of the cube truck.

The 49-year-old male driver of the cube truck suffered life-threatening injuries and was taken to hospital.

Drivers have been told to expect delays until well into the afternoon.

The collision remains under investigation.