I have something to ad about grinding wheels. All grinding wheels have a maximum rpm rating printed on the side of the wheel. This should never be exceeded, or they will come apart.
Working in a machine shop, there are a lot of jobs that we cannot do with a proper shield in place. I was taught early on to stand off to the side of the wheel when first starting the grinder. If the wheel does explode, the pieces usually fly in line with the rotation of the wheel.
I had a shop teacher that used to show off his mis-figured finger, that he had caught between a guard and grinding wheel. He always used to say, that if you cut off your finger, they might be able to sew it back on. Then he would show his hand and say that they can't sew hamburger.
I guess I can't really say which is the most dangerous tool in my shop. But what scares the heck out of me, is when people leave flamable containers out. I cannot remember how many times that I found a full one gallon can of alcohol on the welding bench.
A lot of safety training emphasizes keeping the work area clean and orderly. I would say that the flamable containers would have to rate at the top of the list.
