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. WITHIN MINUTES, 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 NEARBY. OTHER CWS IN THE AREA IMMEDIATELY RESPONDED, ATTENDING TO THE SERIOUSLY INJURED CW AND EXTINGUISHING VARIOUS SPOT FIRES USING PRE-STAGED FIRE EXTINGUISHERS. A CW AT V-90 CLOSED THE VALVE TO SHUT IN THE GAS SHORTLY BEFORE IGNITION, ALLOWING THE FLAME TO EXTINGUISH WITHIN ABOUT ONE MINUTE. THE PRECISE IGNITION SOURCE AND LOCATION COULD NOT BE DETERMINED TO A CERTAINTY; HOWEVER, AN ELECTROSTATIC DISCHARGE FROM THE GENERATED DUST CLOUD CANNOT BE RULED OUT AS THE IGNITION SOURCE, AND IN PG&E'S OPINION, IS MORE LIKELY THAN OTHER IGNITION SOURCES CONSIDERED. THE INJURED EMPLOYEE WAS TRANSFERRED BY AMBULANCE TO A LOCAL HOSPITAL AND THEN BASED ON THE NATURE OF THE INJURIES MEDEVACKED TO A FRESNO AREA HOSPITAL TO RECEIVE CARE FOR THESE NON-LIFE-THREATENING INJURIES. THIS INCIDENT WAS REPORTED TO THE DOT AND CPUC DUE TO A RELEASE OF GAS RESULTING IN AN INJURY REQUIRING HOSPITAL ADMISSION AND AT LEAST ONE OVERNIGHT STAY.