NORTH SHORE GAS CO

Incident Narrative

ON 4/24/14 AT 2222 HOURS, A NORTH SHORE GAS EMPLOYEE ARRIVED IN THE VICINITY OF THE EVENT. THE EMPLOYEE HAD BEEN DISPATCHED TO 4777 WELLINGTON DRIVE TO COMPLETE A LEAK INVESTIGATION ORDER THAT WAS CREATED AT 2152 HOURS. DURING THE LEAK INVESTIGATION, THE EMPLOYEE SMELLED AN ODOR AT THE CORNER OF WELLINGTON DRIVE AND TRENTON COURT AND DETECTED 0.3% LEL WITH A COMBUSTIBLE GAS INDICATOR (CGI). THE EMPLOYEE NOTICED FERTILIZER AND MULCH IN THE AREA. IN ACCORDANCE WITH PROCEDURES AND TRAINING, THE EMPLOYEE ATTACHED A CHARCOAL FILTER TO THE CGI AND DETECTED 0.0% LEL WITH THE FILTER INSTALLED. THE EMPLOYEE WALKED TOWARDS 4773 TRENTON COURT WHEN THE RESIDENT OF THE AREA FLAGGED THE EMPLOYEE DOWN AND SHOUTED THAT THERE IS A FIRE IN THE RESIDENCE NEXT DOOR. THE EMPLOYEE STARTED TO DIAL 911 AND 4771 TRENTON COURT EXPLODED AT APPROXIMATELY 2243 HOURS. NORTH SHORE GAS STOPPED THE FLOW OF GAS BY CLOSING A SINGLE VALVE AT 0032 HOURS ON 4/26/14 AT THE DIRECTION OF THE LONG GROVE FIRE DEPARTMENT. TWO PEOPLE RECEIVED MEDICAL ATTENTION ONSITE AND WERE RELEASED. OTHER HOMES IN THE AREA WERE DAMAGED DUE TO THE EXPLOSION AND THE EXTENT IS STILL UNDER INVESTIGATION. THE GAS MAIN THAT FED 4771 TRENTON COURT IS A 2"" BLACK PLASTIC DIRECT BURIED MAIN THAT WAS INSTALLED IN 1991. THE GAS SERVICE FOR 4771 TRENTON COURT IS A 1.125"" BLACK PLASTIC SERVICE THAT WAS INSTALLED IN 1996. THE SERVICE DID NOT HAVE AN EXCESS FLOW VALVE AS IT WAS NOT REQUIRED BY CODE AT THE TIME OF INSTALLATION. FOLLOWING THE EVENT, THE GAS MAIN AND ALL ASSOCIATED GAS SERVICE PIPES WERE PRESSURE TESTED ON 5/12/14. THE MAINS AND SERVICES WERE PRESSURE TESTED AT 44 PSIG, THE PRESSURE IN THE LINES AT THE TIME OF THE EXPLOSION FOR 1 HOUR. ALL MAINS AND SERVICES HELD PRESSURE DEMONSTRATING NO LEAKAGE OUT OF THESE LINES. REPRESENTATIVES OF THE ILLINOIS COMMERCE COMMISSION (ICC) PIPELINE SAFETY BRANCH WITNESSED THIS TESTING. THE 4"" BLACK PLASTIC DIRECT BURIED MAIN IN WELLINGTON DRIVE WAS RESTARTED AT APPROXIMATELY 1000 HOURS ON 4/27/14. THE RISER FOR 4771 TRENTON COURT WAS REMOVED FROM THE SITE ON 5/15/14 FOR AN X-RAY AND IS SCHEDULED TO BE PERFORMED ON 5/23/14. THE METER AND REGULATOR ARE NOT IN A CONDITION THAT CAN BE TESTED. 6/4/14: AN X-RAY TEST WAS PERFORMED ON THE RISER PIPE ON 5/23/14 TO TEST THE MECHANICAL ASSEMBLY. 12/31/14: THE BORESCOPE PERFORMED ON 10/10/14 WAS INCONCLUSIVE. ON 11/3/14 THE RISER ASSEMBLY WAS PRESSURE TESTED AND DID NOT HOLD PRESSURE DUE TO EXTENSIVE DAMAGE TO THE PLASTIC PIPE INSIDE THE RISER. THE HOME APPLIANCES ARE STILL IN THE PROCESS OF BEING TESTED. 9/14/15: A RE-ASSEMBLY OF THE GAS SYSTEM INSIDE OF THE HOUSE IS BEING GENERATED. PGL IS PLANNING AN ADDITIONAL TEST ON THE RISER. 12/15/15: THE RE-ASSEMBLY AND TESTING OF THE GAS SYSTEM INSIDE OF THE HOUSE WAS COMPLETED. 6/27/17: FURTHER EXAMINATION OF THE RISER DETERMINED A STIFFENER HAD NOT BEEN INSTALLED IN THE SERVICE, AS WAS THE PRACTICE AT THE TIME THE SERVICE WAS INSTALLED. HOWEVER, THERE IS NO INDICATION THAT THE RISER WAS LEAKING OR THAT THERE WAS A PATH FOR THE GAS TO TRAVEL FROM THE OUTSIDE OF THE HOUSE INTO THE HOUSE IF GAS HAD BEEN PRESENT. THEREFORE, NSG HAS DETERMINED THAT JURISDICTIONAL GAS PLAYED NO ROLE IN THE CAUSE OF THIS INCIDENT. THE EVENT WAS CAUSED BY CUSTOMER OWNED PIPING AND/OR EQUIPMENT INSIDE THE HOUSE. NSG CONSIDERS THIS INCIDENT CLOSED.