TRANSCONTINENTAL GAS PIPE LINE COMPANY — Gas transmission and gathering — incident on 2018-09-20

Gas transmission and gathering incident in OLD BRIDGE, MIDDLESEX County, NJ. Reported cause: INCORRECT OPERATION. Reported consequences: 0 fatalities, 0 injuries, 0 NATURAL GAS released, $200,000 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: 20180109.

Operator ID: 19570.

Reported incident date: 9/20/2018 9:04.

Location detail: 99+29

Cause detail: VALVE LEFT OR PLACED IN WRONG POSITION, BUT NOT RESULTING IN AN OVERPRESSURE

Cause detail: AT APPROXIMATELY 8:04 AM CST ON 09/20/2018, UNIT #3 @ COMPRESSOR STA 207 WAS SCHEDULED FOR AN AUTOMATIC BLOW DOWN DUE TO AN UPCOMING PROJECT TO REMOVE THE INLET STRAINER. WHEN UNIT #3'S BLOWDOWN VALVE OPENED, GAS ENTERED THE CHARCOAL FILLED DEODORIZER AND WOULD NORMALLY FLOW UP AND OUT OF THE TOP OF THE STACK ABOVE THE BUILDING ROOFLINE TO ATMOSPHERE. DUE TO A 4" DRAIN LINE AT THE BOTTOM OF THE DEODORIZER VESSEL IN THE OPEN POSITION, THE VENTING GAS AND CHARCOAL WERE ABLE TO ENTER INTO THE DRAIN SYSTEM OF COMPRESSOR BUILDINGS 1&2. THIS IN TURN ACTIVATED BOTH BUILDINGS EMERGENCY SHUT DOWN (ESD) SYSTEMS AS DESIGNED AT 20% LEL (ESD) AND 40% LEL (ESD 2). THE STATION WAS SHUT DOWN IN A SAFE STATE AND THE BUILDING'S FANS EVACUATED THE GAS. WILLIAMS' PERSONNEL RESPONDED TO THE SITE AND INITIATED THE STATIONS EMERGENCY ACTION PLAN WITH THE LOCAL EMERGENCY RESPONDERS.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: INCORRECT OPERATION — INCORRECT VALVE POSITION.

PHMSA indexed costs: $231,540 reported total cost, $110,850.437 in 1984 dollars, $272,367.834 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.