A fire that halted production at a General Motors (GM) plant for a full day on 19 December was caused by a forklift accident, according to a Detroit Free Press report.

"Our initial investigation indicates a forklift accidentally punctured a container with battery materials causing the fire," GM spokeswoman Tara Kuhnen told the news outlet.

The fire halted production of electric vehicles at Factory Zero in Detroit, where GM assembles its GMC Hummer electric pickup and SUV and the Chevrolet Silverado EV work truck.

The Detroit Fire Department sent 18 fire trucks and 60 firefighters to battle the blaze, which broke out at the plant's shipping dock area.

Detroit Fire Chief James Harris said the plant was evacuated and the fire extinguished with no injuries.

He said the fire involved "some lithium-ion batteries".

About 1,880 people work at Factory Zero, named for the zero-emission vehicles it produces.