DURING KILN SHUTDOWN, EMPLOYEE WAS SUPERVISING CONTRACT LABOR AND MAKING AN INSPECTION OF THE KILN CHAIN SYSTEM REPAIR. HE WAS INSIDE THE ROTARY KILN AND WALKING THROUGH THE 4 START CHAIN SYST EM WHEN HE STEPPED ON A CHAIN. IT ROLLED OVER, CAUSING HIS RIGHT FOOT TO SLIP OFF OF IT. HIS RIGHT KNEE TWISTED AS HIS FOOT LANDED ON OTHER CHAIN, CAUSING STRAIN OF HIS RIGHT KNEE.