EMPLOYEE WAS OPERATING CAT ROAD MAINTAINER WHEN HE HEARD NOISE IN THE ENGINE COMPARTMENT. HE GOTOUT OF THE CAB, WITH ENGINE IDLING, TO CHECK THENOISE OUT. HE PEERED THROUGH THE GUARD OVER THE FAN/V BELT DRIVE BUT COULD NOT SEE ANYTHING SO HE LOWERED HIS DARK SAFETY GLASSES TO LOOK AGAIN& THE V-BELT BROKE AND SLAPPED THE INSIDE OF THEGUARD. DUST FLEW AND GOT INTO HIS EYE.