CONSUMERS ENERGY CO — Gas transmission and gathering — incident on 2016-09-22

Gas transmission and gathering incident in IRA, ST. CLAIR COUNTY County, MI. Reported cause: INCORRECT OPERATION. Reported consequences: 0 fatalities, 0 injuries, 3680 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: 20160085.

Operator ID: 2748.

Reported incident date: 9/22/2016 8:33.

Location detail: VALVE #604

Cause detail: OTHER INCORRECT OPERATION

Cause detail: ON SEPTEMBER 22, 2016 AT APPROXIMATELY 08:33 THE ST. CLAIR PLANT II DISCHARGE HEADER FIREGATE BLOCK VALVE #604 AT CONSUMERS ENERGY ST. CLAIR COMPRESSOR STATION PLANT II UNEXPECTEDLY FAILED TO THE CLOSED POSITION DUE TO LOCAL LOSS OF ELECTRIC POWER TO THE ACTUATOR CONTROLS. CONSUMERS ENERGY 'S ST. CLAIR COMPRESSOR STATION IS LOCATED IN IRA, MICHIGAN (ST. CLAIR COUNTY). THE VALVE CLOSURE RESULTED IN A BLOCKED DISCHARGE FROM UNIT 2-4, WHILE IT WAS OPERATING. AS PRESSURE ON THE DISCHARGE LINE INCREASED TO 1430 PSIG, THE RELIEF VALVE ON THE DISCHARGE OF THE UNIT OPENED RELIEVING PRESSURE ON THE LINE TO 1255 PSIG. THE RELIEF VALVE CYCLED FOR APPROXIMATELY ONE HOUR PRIOR TO THE BLOCK VALVE BEING IDENTIFIED AS THE CAUSE OF THE FAILURE. THE VALVE WAS RETURNED TO THE OPEN POSITION, AND NORMAL OPERATION WAS CONTINUED AT APPROXIMATELY 10:06. A LOCAL INVESTIGATION DETERMINE A LOSS OF POWER CAUSED THE EMERGENCY SHUT DOWN (ESD) TO OPERATE AT THE STATION. THE ESD OPERATION TRIGGERED GATE VALVE #604 TO TRAVEL WHEN NOT INTENDED LEADING TO AN UNPLANNED GAS RELEASE. ADDITIONAL INCIDENT ANALYSIS CONCLUDED THE PRIMARY CAUSE OF THE POWER OUTAGE WAS ON-SITE ELECTRICAL RE-WORK BEING PERFORMED BY A SECOND PARTY CONTRACTOR INVOLVED IN THE STATION UPGRADE PROJECT.

PHMSA trend classification: not significant, not serious.

PHMSA standardized cause: INCORRECT OPERATION — OTHER INCORRECT OPERATION.

PHMSA indexed costs: $10,700 reported total cost, $11,355.319 in 1984 dollars, $13,982.542 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.