MAINTENANCE SUPERVISOR WAS TRYING TO INSPECT THE #1 KILN BURNER PIPE DURING A TEMP. OUTAGE BY LOOKING THROUGH THE SMALL INSPECTION DOOR UNDER THE BURNER PIPE. AT APPROX. 8 AM WHILE LOOKING AT THE BURNER PIPE, A SUDDEN PUFFING OF DUST OCCURRED & DUST PARTICLE GOT INTO HIS RT. EYE THROUGH HIS SIDE-SHIELDED SAFETY GLASSES REQUIRING MEDICAL ATTN. & RX DROPS TO HEAL.