I have been in this trade (HVAC) along with an apprenticeship with the pipe fitters for over 30 years. In that time I had only 1 lost time injury. I was mounting a 40hp motor in a Trane SEHC in Beaumont, TX and the motor dropped due to broken hook on the chain fall. For my part I was too stupid to let go and shatter 3 disc's in my back. I had a great neurosurgeon who put me back together again. As bad as the injury was my employer at the time had a mandatory meeting scheduled back in Houston, 115 miles away. When I reported my injury I was told to drive back to town, aggravating my injury to the point I could not get out of my van. Since then I tend to use my brain more then my body. Since I was ordered to drive back a lawyer pretty much set things right after all was said and done. You have to be careful and think about what you are doing, how your going to do it, what hazards exist around the job, how you can work around them, safely. Each job has its own hazards and the smart people recognize them and avoid them.