ATLANTA GAS LIGHT CO — Gas transmission and gathering — incident on 2004-02-22

Gas transmission and gathering incident in JESUP, WAYNE County, GA. Reported cause: 9. Reported consequences: 0 fatalities, 0 injuries, $202,091 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20040029.

Operator ID: 792.

Reported incident date: 2/22/2004.

Cause detail: THIRD PARTY EXCAVATION DAMAGE

Cause detail: THIS EVENT IS STILL UNDER INVESTIGATION. THERE HAS BEEN RECENTLY LOGGING AND UNAUTHORIZED GRADING WITHIN THE RIGHT-OF-WAY OF THIS PIPE. ATLANTA GAS LIGHT COMPANY'S RIGHT-OF-WAY SURVEYOR, WHO HAD WALKED THIS LINE A WEEK BEFORE THE INCIDENT, REPORTED SIGNIFICANT LANDSCAPE AND GRADING CHANGES. ATLANTA GAS LIGHT COMPANY WAS MADE AWARE OF THE PIPELINE FAILURE THROUGH MONITORING PRESSURE LOGS AT JESUP AND BELLE VISTA, DOWNSTREAM OF THE FAILURE. 6-28-04 ON SUNDAY, FEBRUARY 22, 2004 AT APPROXIMATELY 1:30 AM, A SECTION OF THE BRUNSWICK LATERAL 7.5 MILES SOUTH OF THE DOCTORTOWN (JESUP) MAINLINE VALVE (MLV) FAILED. THE PRESSURE DROP WAS FIRST NOTED BY ATLANTA GAS LIGHT COMPANY PERSONNEL AT 1:35AM. THIS LINE IS LOCATED ON AN EASEMENT OWNED BY AGLC. IN THE WEEK PRIOR TO THE INCIDENT, THE RIGHT-OF-WAY WAS INSPECTED BY AGLC PERSONNEL AND THE GRASS WAS MOWED. AT THE TIME OF THAT INSPECTION, NO UNUSAL CONDITIONS WERE NOTED. CONVERSELY, IN THE POST-INCIDENT INSPECTION THE FOLLOWING FACTS WERE MOTED: 1. HEAVY MACHINERY USED IN CONSTRUCTION AND GRADING ACTIVITIES WAS FOUND PARKED IN THE RIGHT-OF-WAY. 2. A DIRT PATH HAD BEEN ESTABLISHED ROUGHLY PERPENDICULAR TO THE PIPE ACROSS THE RIGHT-OF-WAY. TIRE TRACKS WERE NOTED, INDICATING THAT THE HEAVY MACHINERY HAD CROSSED THE PIPE AT THIS LOCATION. 3. A DRAINAGE CULVERT HAD BEEN INSTALLED ROUGHLY PERPENDICULAR TO AND UNDER THE PIPE ACROSS THE RIGHT-OF-WAY. VISUAL INSPECTION OF THE RUPTURED PIPE AND FRAGMENTS FOUND ON-SITE SHOWED A GOUGE IN THE PIPE. THE RUPTURE OCCURRED AT THE CULVERT WHERE THE SOIL WAS SATURATED. SUBSEQUENT LABORATORY ANALYSIS INDICATED THAT THE GOUGE CONTAINED FRAGMENTS OF FOREIGN METALS, INDICATING DAMAGE BY A METALLIC OBJECT-MOST LIKELY THE HEAVY CONSTRUCTION EQUIPMENT SEEN ON-SITE. IT WAS DETERMINED THAT EMBRITTLEMENT DUE TO HYDROGEN STRESS CRACKING OCCURRED AT THE SITE OF THE GOUGE. THIS CRACKING WAS ACCELERATED DUE TO THE HIGH MOISTURE CONTENT OF THE SURROUNDING SOIL, AND ULTIMATELY LED TO THE FAILURE OF THE PIPE.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: EXCAVATION DAMAGE — THIRD PARTY EXCAVATION DAMAGE.

PHMSA indexed costs: $202,091 reported total cost, $122,612.575 in 1984 dollars, $220,782.931 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.