PACIFIC GAS & ELECTRIC CO — Gas transmission and gathering — incident on 2016-06-05

Gas transmission and gathering incident in PATTERSON, STANISLAUS County, CA. Reported cause: MATERIAL FAILURE OF PIPE OR WELD. Reported consequences: 0 fatalities, 0 injuries, 129000 NATURAL GAS released, $773,015 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: 20160056.

Operator ID: 15007.

Reported incident date: 6/5/2016 5:16.

Location detail: MP 1.79

Cause detail: ENVIRONMENTAL CRACKING-RELATED

Cause detail: ON JUNE 5, 2016 AT 0516 HOURS, PG&E WAS NOTIFIED OF A TRANSMISSION LINE LEAK ON L-215 AT APPROXIMATELY MILE POINT (MP) 1.79. THE NEAREST ADDRESS IS 1607 WEST MARSHALL RD, PATTERSON. PG&E'S GAS SERVICE REPRESENTATIVE (GSR) ARRIVED ON-SITE AT 0608 HOURS AND REPORTED GAS BLOWING FROM THE 12 INCH TRANSMISSION LINE. THE DIRECT CAUSE OF THE FAILURE IS STRESS CORROSION CRACKING. THE OPERATIONS EMERGENCY CENTER (OEC) WAS ACTIVATED AND PG&E CREWS ISOLATED THE LINE BY 0954 HOURS BY CLOSING MANUAL VALVES. TWENTY SIX CUSTOMERS WERE IMPACTED AS A RESULT OF THIS INCIDENT. PG&E DEPLOYED MOBILE NATURAL GAS SERVICE TO SUPPORT THE IMPACTED CUSTOMERS DURING THE REPAIRS. SERVICE WAS RESTORED TO THE CUSTOMERS BY 6/7/16 AT 0940 HOURS. THE PIPE WAS RE-INSTALLED AND THE SITE WAS RESTORED BY 6/14/16. THE VOLUME OF NATURAL GAS UNINTENTIONALLY RELEASED IS APPROXIMATELY 129 MMCF. THERE WERE NO INJURIES, FATALITIES, OR IGNITION ASSOCIATED WITH THIS INCIDENT. THIS INCIDENT WAS REPORTED TO THE DOT AND CPUC DUE TO THE UNINTENTIONAL RELEASE OF GAS, REPAIR COSTS EXCEEDING $50K AND RELEASE OF GAS ESTIMATED WAS GREATER THAN 3 MILLION CUBIC FEET. PG&E TIED IN THE EASTERN SECTION OF L-215 AT MP 4.89 ON SEPTEMBER 26, 2016 AT APPROXIMATELY 2130 HOURS. THE WESTERN SECTION OF L-215, MP 0.278, WAS TIED BACK INTO THE SYSTEM ON NOVEMBER 5, 2016, AT APPROXIMATELY 1800 HOURS. THE LINE WAS RE-PRESSURIZED AT A REDUCED PRESSURE 600 PSIG UNTIL STRENGTH TESTING CAN BE COMPLETED. TO MITIGATE THE THREAT OF SCC, A HYDROSTATIC RETEST PROGRAM WAS IMPLEMENTED ON LINE 215 AND COMPLETED IN MAY 2017. EACH SECTION OF HTE LINE WITH THE IDENTIFIED THREAT WAS SPIKE TESTED TO NO LESS THAN 100% OF THE SPECIFIED MINIMUM YIELD STRENGTH (SMYS). ALL HYDROSTATIC TESTS WERE SUCESSFUL WITH NO FAILURES OF ANY KIND. FURTHER, PG&E HIRED A THIRD PARTY, KIEFNER AND ASSOCAITES, WHO CONDUCTED A FITNESS FOR SERVICE (FFS) ASSESSMENT OF LINE 215, AND THE FINDINGS REFLECT THAT "THE 2016 HYDROSTATIC PRESSURE SPIKE TEST CONFIRMED THE FITNESS FOR SERVICE OF LINE 215 FOR ITS MAOP OF 890 AT THE TIME OF THE TEST AND CONTINUES TO BE A VALID STRENGTH TEST AT PRESENT TIME." BASED ON THE COMPLETION OF ASSESSMENT ACTIVITIES, PG&E IS PLANNING TO RESTORE PRESSURE DURING THE WEEK OF DECEMBER 18, 2017.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: MATERIAL FAILURE OF PIPE OR WELD — ENVIRONMENTAL CRACKING-RELATED.

PHMSA indexed costs: $1,116,241 reported total cost, $748,208.604 in 1984 dollars, $1,395,600.599 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.