EE SUSTAINED A SPRAINED RIGHT ANKLE. INJURY OCCURRED WHILE THE EE WAS STEPPING ACROOSS 3 18"" PIPES THE INJURY OCCURRED NORTH OF THE CONCENTRATOR, AFTER DUSK, PRIOR TO END OF SHIFT. EE STEPPED UP, CROSSED & WAS IN PROCESS OF STEPPING DOWN FROM THE PIPES. AS THE EE STEPPED DOWN FROM THE PIPES, HIS RIGHT ANKLE ROLLED OUTWARD FROM LANDING ON UNEVEN GROUND. EE REC'D