ROTARY KILN UTILITY OPERATOR WAS WORKING THE NIGHT SHIFT ON OCT 1, 00 WITH THE OPERATION OF THE #1 AND #2 KILNS. AT APPROX 5:00 AM WHILE DESCENDING THE FEED AND STAIRWAY BELOW #2 KILN, HE TWIS TED HIS LEFT ANKLE WHILE COMING OFF THE BOTTOM STEP TO THE GROUND. HE GOT ICE AND A WRAP AND GOT REST. WHEN HE AWOKE, THE ANKLE HAD GOTTEN WORSE AND SWOLLEN. E.R. SHOWED SEVERE ANKLE STRAIN.