EE WAS UTILIZING A RIGHT ANGLE GRINDER TO REMOVE ROUGH EDGES IN PREP. OF WELDING TASK ON THE CL-520 SCREW IN THE QUARRY/MAINTENANCE SHOP. EE INDICATED THAT SAFETY GLASSES WERE BEING USED AT TH E TIME OF THIS ACCIDENT HOWEVER A FOREIGN BODY ENTERED THE LEFT EYE REQUIRING MEDICAL TREATMENT TO BE REMOVED.