PACIFIC GAS & ELECTRIC CO

Incident Narrative

"ON WEDNESDAY, JULY 10, 2024, AT APPROXIMATELY 21:04 HOURS, PG&E INCIDENT ON-DUTY PERSONNEL CONFIRMED A RELEASE OF GAS AT KETTLEMAN COMPRESSOR STATION RESULTED IN AN INJURY NECESSITATING IN-PATIENT HOSPITALIZATION. FOLLOWING COMPLETION OF CONSTRUCTION, CLEARANCE ACTIVITIES TO RE-INTRODUCE GAS AND PURGE AIR FROM THE SYSTEM, INITIATED: - THE APPROVED CLEARANCE REQUIRED V-56 TO BE ""CHECKED OPEN"" FOR PURGING, HOWEVER, IT HAD BEEN CLOSED FOR STEM SEAL REPLACEMENT WORK ON JULY 8, 2024, AND ONLY PARTIALLY OPENED PRIOR TO THE PURGE - OPERATIONS THAT HAD NOT BEEN DOCUMENTED NOR APPROVED AS PART OF THE SEQUENCE OF OPERATIONS IN THE CLEARANCE. - GAS WAS RE-INTRODUCED TO THE SYSTEM FROM A 34'' CONTROL VALVE (V-90), A CLEARANCE POINT WITH 618 PSI. THERE ARE TWO WAYS TO OPERATE V-90, MANUAL HYDRAULIC AND MANUAL PNEUMATIC. - WHEN ATTEMPTING TO MANUALLY OPERATE V-90 HYDRAULICALLY, OIL UNEXPECTEDLY DISCHARGED FROM THE ACTUATOR'S MANUAL HYDRAULIC OVERRIDE SYSTEM RELIEF VALVE AND THE VALVE FAILED TO OPERATE. - V-90 WAS THEN PARTIALLY OPENED USING THE MANUAL PNEUMATIC CONTROLS. THIS METHOD IS NOT EFFECTIVE FOR FINE THROTTLING AS REQUIRED FOR PURGING IN DESIGN STANDARD A-38. GAS FROM V-90 BEGAN TO DISPLACE AIR AT MULTIPLE VENT LOCATIONS PER THE ESTABLISHED CLEARANCE PLAN. IT IS SUSPECTED THAT AS A RESULT OF THE PARTIAL OPEN POSITION OF V-56, A GREATER AMOUNT OF GAS FLOW WAS DIRECTED TOWARD V-78. INSTEAD OF GAS EXITING THE 1/2'' VERTICAL VENT VALVE DOWNSTREAM OF V-78 AS APPROVED IN THE CLEARANCE, GAS EXITED THE FULL 6'' PIPE OPENING HORIZONTALLY WHERE THE BLIND FLANGE HAD BEEN REMOVED ON JULY 9. GAS FLOWED DIRECTLY INTO AN OPPOSING BLIND FLANGE ROUGHLY 20'' AWAY AT V-79. THIS RESULTED IN DEFLECTION IN ALL DIRECTIONS, INCLUDING INTO THE EXCAVATION BELOW. A HAZARDOUS AIR-GAS PLUME DEVELOPED. AT APPROXIMATELY 18:42 HOURS, THE AIR-GAS PLUME IGNITED, RESULTING IN SERIOUS BURNS TO ONE COWORKER AND MINOR INJURIES TO OTHERS. CWS IN THE AREA IMMEDIATELY RESPONDED, ATTENDING TO THE INJURED CW AND EXTINGUISHING VARIOUS SPOT FIRES USING PRE-STAGED FIRE EXTINGUISHERS. A CW CLOSED V-90 TO SHUT IN THE GAS BEFORE IGNITION, ALLOWING THE FLAME TO EXTINGUISH IN ABOUT ONE MINUTE. PROCEDURE USE & ADHERENCE WAS THE APPARENT CAUSE OF THIS INCIDENT. CONFIGURATION CONTROL WAS NOT APPLIED WHEN CLEARANCE WORK WAS EXECUTED. PRIOR TO PURGING INTO SERVICE, CWS FAILED TO RECOGNIZE A HIGH ENERGY ESSENTIAL CONTROL HAD BEEN DISABLED DURING THE PURGE OUT OF SERVICE. PROCEDURES INVOLVING PURGING GAS FACILITIES, INSTALLATION AND OPERATION OF AIR MOVERS, AND TEMPORARY VENT STACKS PROVIDE A BARRIER IN THE FORM OF REQUIREMENTS TO CALCULATE AND MONITOR PURGE DRIVE PRESSURE, PROPERLY SIZE AIR MOVERS AND FRESH AIR SOURCES, AND INSTALL TEMPORARY VENT STACKS TO SAFELY DISPERSE GAS TO ATMOSPHERE. PROCEDURE INVOLVING NEW CLEARANCES FOR GT FACILITIES PROVIDES A BARRIER IN THE FORM OF CHANGE MANAGEMENT FOR THE CLEARANCE PROCESS AND ENDORSEMENT REQUIREMENTS, WHICH FAILED AS THE CLEARANCE TEAM DID NOT FOLLOW THEM. THE PRECISE IGNITION SOURCE AND LOCATION COULD NOT BE DETERMINED TO A CERTAINTY; HOWEVER, THE FOLLOWING POTENTIAL IGNITION SOURCES WERE ASSESSED AND COULD NOT BE RULED OUT. AN ELECTROSTATIC DISCHARGE FROM THE GENERATED DUST CLOUD. AN ELECTROSTATIC DISCHARGE FROM EITHER THE PIPELINE ITSELF (DUE TO CHARGING FROM THE VENTING GAS) OR AN ELECTROSTATIC DISCHARGE FROM AN EMPLOYEE IN THE VICINITY OF THE VENTING GAS (DUE TO ELECTROSTATIC ACCUMULATION ON THEIR PERSON). A MECHANICAL SPARK FROM DEBRIS EXITING THE PIPELINE AT HIGH VELOCITY OR KICKED UP BY THE VENTING GAS. ELECTRICAL EQUIPMENT IN THE VICINITY OF THE VENTING GAS WAS LOCKED OUT AND TAGGED OUT AND WAS RULED OUT AS A POTENTIAL IGNITION SOURCE. THE INJURED EMPLOYEE WAS TRANSFERRED BY AMBULANCE TO A LOCAL HOSPITAL AND THEN MEDEVACKED TO A FRESNO AREA HOSPITAL TO RECEIVE CARE. THIS INCIDENT WAS REPORTED TO THE DOT AND CPUC DUE TO A RELEASE OF GAS RESULTING IN AN INJURY REQUIRING HOSPITAL ADMISSION FOR OVERNIGHT STAY."