It is a cold hard fact that if you work with heavy stuff that moves (and lots of other things), you can (and will) get hurt eventually.  How badly you are hurt depends, I like to think, on whether or not your number is up.  I used to work as the derrickman in the old steel oil rigs.  Lots of ways to get hurt there.  I was lucky, but friends/co-workers weren't always...
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OBG