TENNESSEE GAS PIPELINE COMPANY — Gas transmission and gathering — incident on 2018-07-16

Gas transmission and gathering incident in AGAWAM, HAMPDEN County, MA. Reported cause: EQUIPMENT FAILURE. Reported consequences: 0 fatalities, 0 injuries, 8610 NATURAL GAS released, $0 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: 20180082.

Operator ID: 19160.

Reported incident date: 7/16/2018 20:51.

Location detail: 261

Cause detail: MALFUNCTION OF CONTROL/RELIEF EQUIPMENT

Cause detail: ON JULY 16, 2018 AT 8:51 PM EDT, AN EMERGENCY SHUTDOWN (ESD) WAS INADVERTENTLY ACTIVATED RESULTING IN THE BLOWDOWN OF THE TGP AGAWAM COMPRESSOR STATION NO. 261. VALVE BS-1, WHICH IS ONE OF THE STATION ESD ISOLATION VALVES, DID NOT CLOSE RESULTING IN AN EXTENDED VENTING PERIOD OF 33 MINUTES. AN ESTIMATED 8,610 MCF OF NATURAL GAS WAS RELEASED TO THE ATMOSPHERE. THE ESD ACTIVATED WHEN THE SYSTEM WAS RETURNED TO NORMAL MODE, HAVING PREVIOUSLY BEEN IN BYPASS MODE TO ALLOW FOR WELDING ACTIVITIES IN ONE OF THE COMPRESSOR BUILDINGS. INVESTIGATION REVEALED THAT POWER GAS TO THE OPERATOR FOR VALVE BS-1 WAS BLOCKED DUE TO A CLOSED VALVE IN THE OPERATOR'S GAS SUPPLY LINE, RESULTING IN THE ISOLATION VALVE FAILING TO CLOSE AND THE PROLONGED GAS RELEASE. A 48-HOUR UPDATE WAS PROVIDED TO THE NRC ON JULY 18, 2018 AT 3:07 PM EDT, NRC REPORT NO. 1218764, PROVIDING THE VOLUME OF GAS RELEASED WHICH WAS UNKNOWN AT THE TIME OF THE ORIGINAL NOTIFICATION ON JULY 16.

PHMSA trend classification: not significant, not serious.

PHMSA standardized cause: EQUIPMENT FAILURE — MALFUNCTION OF CONTROL/RELIEF EQUIPMENT.

PHMSA indexed costs: $24,664 reported total cost, $22,817.02 in 1984 dollars, $28,293.074 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.