"400". "Approximate number of deaths attributed to workplace electrocutions per year." from June 2008 edition of EC&M magazine.
Working hot intentionally, and troubleshooting, which needs to be hot much of the time are definitely dangerous, especially in an industrial setting, which is where I have the majority of my experience.
Proper use of LOTO cannot be understated. Already in my apprenticeship I have seen JWs "Tag Out" circuit breakers with electrical tape.
I pulled a piece of surface metal raceway accidentally off the wall when removing data cable from one side of it (the 120V duplex recs were separated by a internal divider). I pulled the cover off and found wire nut splices for the 120. I told the JW I could disconnect them here (hot), so that I could 'safely' re-attach the raceway to the wall.
Knowing my industrial experience, he said OK, I will watch, go ahead "Do you have your side cutters?" (to untwist the 12AWG solid wires). I said "Yes, but they are not my insulated ones".
He said "It doesn't matter". Well, it matters to me. Just an added measure of safety. What if your plier grips are not insulated, and you are inadvertently grounded?
There was no load on the circuit, so no current flowing in the conductors, no arc when disconnecting. I have done this many times before, so was comfortable doing it.
That's probably the most dangerous thing we can do in our biz. Comfortable is okay, you can't be scared. You DO have to be respectful of the danger, and DO NOT be careless, or reckless, or lackadazical.
PAY ATTENTION to where your hands are!!! (And your elbows), When working Hot: Wear Insulated gloves, Use Insulated tools, Wear safety glasses, CONCENTRATE.
Sometimes, things happen that are out of our control. Most of the time we control our own fate.
It is terribly unfortunate that people die at work. Everyone should be able to go home at the end of the day.