Probably the most tragic example in history of what can happen when lock-out/tag-out procedures are not enforced and followed.
I knew people that died on Piper Alpha and I had worked on the platform myself. I’ll never forget that day. I was driving down the highway in Colorado when I heard what had happened on the radio. I had to pull off and it was about an hour before I could go on. I didn’t know at that time that several friends and colleagues had just died.