PEOPLES GAS LIGHT & COKE CO

Incident Narrative

ON AUGUST 20, 2014 AT 1555 HOURS, A PEOPLES GAS CREW WAS RE-PRESSURIZING A 20"" DUCTILE IRON MEDIUM PRESSURE MAIN AT THE INTERSECTION OF EAST 80TH STREET AND CRANDON AVENUE IN CHICAGO, ILLINOIS. PRIOR TO RE-PRESSURIZING THE MAIN, THE CREW PLACED A CONCRETE THRUST BLOCK AGAINST THE CAP THAT WAS ATTACHED TO THE END OF THE MAIN IN THE EXCAVATION. TWO EMPLOYEES WERE WORKING ON THE OPPOSITE SIDE OF THE EXCAVATION ON A DEAD SECTION OF THE MAIN, PREPARING IT FOR INSERTION. AFTER THE LIVE SIDE HAD BEEN RE-PRESSURIZED TO LINE PRESSURE OF 22 PSIG, AN UNEXPOSED MECHANICAL JOINT FAILED, CAUSING THE SEGMENT OF THE LIVE MAIN TO DISLODGE. AS A RESULT OF THE PRESSURE FROM THE SEPARATION, THE MAIN SEGMENT HIT AND PUSHED THE THRUST BLOCK TO THE OTHER SIDE OF THE EXCAVATION, INJURING THE TWO EMPLOYEES. THE EMPLOYEES WERE TREATED AND RELEASED FROM A HOSPITAL THE SAME DAY, WITHOUT BEING FORMALLY ADMITTED. IT WAS DETERMINED THAT THE THRUST BLOCK WAS NOT ADEQUATELY SIZED ACCORDING TO THE PROCEDURE FOR THIS TYPE OF WORK AND THE APPARENT CAUSE IS LISTED AS INCORRECT OPERATION. ALTHOUGH THIS INCIDENT DOES NOT MEET THE REPORTING CRITERIA IN 49 CFR 191.3 (1) OR (2), AN INCIDENT REPORT IS BEING SUBMITTED TO FOLLOW UP ON THE INITIAL TELEPHONIC REPORT MADE TO THE NATIONAL RESPONSE CENTER.