A worker at the plant was showing a co-worker how to perform a task on the automatic guided vehicle repair crib on Dec. 17, 2012.
The worker provided the co-worker with the preliminary steps before being called away and by the time the worker returned all but one screw had been removed from the assembly.
The worker began to show how to complete the operation while sitting on top of the frame, but there was no blocking material in place to prevent the lift table from falling.
The lift table fell on top of the worker, who suffered a number of broken bones and was extracted after other workers raised the lift table with pry bars.
A Ministry of Labour investigation determined that the cause of the lift table collapse was the failure of the assembly's remaining screw.
General Motors pleaded guilty to failing as an employer to ensure that temporarily elevated machinery under which a worker may pass or work was securely and solidly blocked.