EE CLAIMS THAT AS HE WAS STARTING TO CLIMB THE STAIRS TO THE ROTARY KILN PREHEATER, HIS RIGHT FOOT SLIPPED AS HE PLACED HIS RIGHT FOOT ON THE FIRST RUNG OF THE STAIRS. HE THINKS HE MIGHT HAVE STEPPED ON A ROCK. THERE WAS NO EVIDENCE OF LOOSE ROCK OR SLIPPERY MATERIAL IN THE AREA OF THE ALLEGED ACCIDENT. HE WAS RELEASED TO RETURN TO LIGHT DUTY BY HIS DR.