If you have a CNC machine, which I don’t, and you’re fond of all your limbs, which I am, you may want to take a look at the cool safety guide they made over at RS’s Info Zone. Click on the picture to go to the full sized one. Print it out and hang it close to the machine to remind you!
Maybe they should make one about leaving LEGO bricks on the floor. I reckon that’s almost as dangerous!