EMPLOYEE WAS WORKING WITH TWO OTHER EMPLOYEES (WHO WERE INSIDE SCREEN) CHANGING THE SIMPLICITY SCREEN ON THE VERTICAL IMPACT CRUSHER. EMPLOYEE STEPPED OFF SCREEN ONTO A BEAM AND THEN ONTO A DU STY HANDRAIL. HIS FOOT SLIPPED. HE TRIED TO CATCH HIMSELF, TWISTING HIS BODY TO THE LEFT. HE THEN LANDED ON HIS LEFT WRIST. HE FELL APPROX 4-5'.