The hazard
Cranes lift and swing heavy loads near workers and power lines, often on ground that can shift. When something goes wrong, it happens fast. The operator is not the only one at risk: riggers, signal persons, laborers and anyone walking by can be struck, crushed or caught under a load.
The action
In construction, with a few exceptions, each operator must be trained, certified or licensed, and evaluated before running a crane. Until then, a worker may only operate as an operator-in-training, continuously monitored by a trainer (29 CFR 1926.1427(b)(2)). In general industry, only designated personnel may operate an overhead or gantry crane (29 CFR 1910.179(b)(8)). Never take the controls just because you have seen it done. (29 CFR 1926.1427(a))
ASK THE CREW
Who is our signal person, and what does the emergency stop signal look like?
From the talk: Crane safety. Read it in full, free, with the questions and the sign-in sheet.