The hazard
Machines can start up without warning, and stored energy can be released even after the power is off. Lockout tagout keeps a machine from moving or releasing energy while someone is working on it. It only works when everyone follows the same steps, every time.
The action
Before work starts, the authorized employee must verify that the machine is isolated and de-energized. A common check is to clear everyone from the area, try the normal start controls, then return them to off. Do not take anyone's word that it is dead. (29 CFR 1910.147(d)(6))
ASK THE CREW
Where are our lockout procedures kept, and when did you last read the one for your machine?
Takeaway: Before you reach in, lock it out, try it, and keep your key until the job is done.
From the talk: Lockout/tagout (LOTO). Read it in full, free, with the questions and the sign-in sheet.