ANR PIPELINE CO — Gas transmission and gathering — incident on 2017-09-02

Gas transmission and gathering incident in SANDWICH, KENDALL County, IL. Reported cause: INCORRECT OPERATION. Reported consequences: 0 fatalities, 0 injuries, 8900 NATURAL GAS released, $1,000 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: 20170085.

Operator ID: 405.

Reported incident date: 9/2/2017 4:29.

Location detail: 795

Cause detail: PIPELINE OR EQUIPMENT OVERPRESSURED

Cause detail: AT 4:20AM CT ON SEPTEMBER 2, 2017, THE AREA MANAGER RECEIVED A CALL FROM A NEIGHBORING RESIDENT THAT GAS WAS VENTING FROM THE COMPRESSOR STATION. PERSONNEL WERE DISPATCHED TO INVESTIGATE. SHORTLY AFTER 4:29AM, FIELD PERSONNEL IDENTIFIED TWO VALVES INCORRECTLY POSITIONED FROM A PREVIOUS OPERATION. AFTER THESE VALVES WERE CORRECTLY POSITIONED, THE RELIEF VALVES STOPPED VENTING. IT WAS DETERMINED THAT THE 6" RELIEF VALVES VENTED INTERMITTENTLY (DUE TO PRESSURE INCREASING AND DECREASING ABOVE AND BELOW THE SET POINT) FOR ABOUT 31 MINUTES WHEN THE PRESSURE IN THE PIPELINE REACHED 850 PSIG. THE EVENT MET THE DEFINITION OF INCIDENT BASED ON AN UNINTENDED GAS RELEASE EXCEEDING 3MMCF.

PHMSA trend classification: not significant, not serious.

PHMSA standardized cause: INCORRECT OPERATION — PIPELINE/EQUIPMENT OVERPRESSURED.

PHMSA indexed costs: $29,200 reported total cost, $26,113.503 in 1984 dollars, $34,176.058 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.