Abstract: WORKERS WERE COMPLETING A LOW PRESSURE NITROGEN TEST ON 115-KILOVOLT CONDUIT CABLES. THE FOREMAN ASSIGNED TO THIS TASK WAS TRANSFERRED TO ANOTHER JOB. THE EMPLOYEES WERE WRONGLY LED TO BELIEVE THAT A SUBSTITUTE FOREMAN WAS TO SUPERVISE THE OPERATION. AN INCORRECT PROCEDURE WAS USED IN PURGING THESE LINES. AS A RESULT, THE CONDUIT VAULTS WERE FILLED WITH NITROGEN. EMPLOYEE #1 ENTERED A VAULT TO RETRIVE SOME SAFETY CONES, AFTER NOTIFYING THE SUBSTITUTE FOREMAN. THE CONES HAD BEEN PLACED THERE THE PREVIOUS DAY. NEITHER EMPLOYEE #1 NOR THE SUBSTITUTE FOREMAN WAS AWARE OF ANY POSSIBLE HAZARDS. THE SUBSTITUTE FOREMAN AND ANOTHER WORKER WERE FOLLOWING ESTABLISHED POLICY BY FUCTIONING AS ATTENDANTS. EMPLOYEE #1 ENTERED THE VAULT AND PASSED OUT DUE TO A TRANSIENT ANOXIA CONDITION. THE ATTENDANTS INITIALLY ATTEMPTED TO RESCUE EMPLOYEE #1, BUT FOLLOWED INCORRECT PROCEDURES. THEY WERE NOT AFFECTED BY THE NITROGEN, AND WERE EVENTUALLY ABLE TO REMOVE EMPLOYEE #1 FROM THE CONFINED SPACE. THE EMPLOYEES IN THIS INCIDENT WERE NOT TRAINED ADEQUATELY TO HANDLE THE SITUATION.