The truck veered as it approached a bridge at around 6 p.m. Monday on Industrial Boulevard, crashing into the bridge's guardrail and sliding down the embankment on its side.
The badly damaged cab ended up in the river and caught fire with the driver still trapped inside.
The driver was eventually extracted from the wreckage by emergency response personnel and taken to hospital with burns.
His condition is not known at this time.
The truck and the generator held an estimated 4,000 litres of diesel fuel.
An emergency environmental response team was dispatched to the scene to contain any possible spill.
It’s not yet known how much, if any, fuel spilled.