Bill is correct to some extent but some of us also believe that it is far better to teach someone how to avoid getting hurt than it is to try and make the workplace idiot proof. From my experience there is no such thing as idiot proof because eventually there will be an idiot to come along and prove that wrong. Only occasionally is equipment failure the problem and often if it is it's from lack of proper maintenance and inspections. What most accidents can be traced back to is unsafe work procedure.
Two years ago I was working on a Conoco Phillips plant site, the largest Steam Assisted Gravity Drainage heavy oil project in the world. While I was there they surpassed the 1.000.000 man hour mark without a single lost time injury, a world record. If you were seen doing something unsafe and they knew you knew better you were let go immediately. If there was anything that you had to do that you were unsure of you were expected to ask before you did it. There were 5000 workers on site so it was a busy place.Nothing got done without a meeting of all concerned to go over the specifics of what was going to happen. That's how you avoid accidents is through training and good planning.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.