Do not allow any worker to operate construction vehicles without license

Any accident foreseen in this frame?

In a material stock yard, an operator worker A and another worker B are working in pair using a hydraulic excavator. Their job is to paint the surfaces of the I-beams one by one that are stacked up there. First the topside of an I-beam is painted. Then it is turned over with a lateral slinging clamp hung to a hook fixed to the bucket of the hydraulic excavator and the rear side is painted. After painting on both sides, it is stacked up using the same clamp.
The operator A has finished a special training course for operating movable type cranes, but has yet to finish a training course for operating construction vehicles, and so far has little experiences with them.
Now what accident do your anticipate from this picture? 

This is the accident resulted?

The worker B was trying to unfasten the clamp from an I-beam that has finished painting, when the inexperienced operator A moved the bucket control lever by mistake. The bucket hit the worker B hard on the chest and killed him.

Tips for forestalling similar accidents

1. Do not allow any worker to operate construction vehicles without the required license.
2. Post a signalman where a job obliges a worker to enter and there is the danger of bodily injuries to him/her by a possible contact with a construction machine in operation.
3. Do not allow a construction machine to be used for any other purpose than its primary application.