OKLAHOMA NATURAL GAS COMPANY, A DIVISION OF ONE GAS, INC. — Gas transmission and gathering — incident on 2019-01-31

Gas transmission and gathering incident in TULSA, TULSA County, OK. Reported cause: INCORRECT OPERATION. Reported consequences: 0 fatalities, 0 injuries, 16800 NATURAL GAS released, $265,000 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: 20190025.

Operator ID: 14210.

Reported incident date: 1/31/2019 15:02.

Location detail: N/A

Cause detail: OTHER INCORRECT OPERATION

Cause detail: A RECENT PIPELINE CONSTRUCTION PROJECT REPLACED PART OF AN ORIGINALLY ALL-WELDED 16-INCH PIPELINE INSTALLED IN 1955. ALTHOUGH OPERATOR RECORDS EXISTED, THE PROJECT DESIGNERS AND REVIEWERS FAILED TO IDENTIFY THAT TWO COUPLINGS HAD LATER BEEN INSTALLED IN 1959. THE CURRENT REPLACEMENT PROJECT CREATED A 90-DEGREE OFFSET IN THE ORIGINAL PIPELINE ROUTE NEAR THE MOST PROXIMATE BURIED COUPLING, AND THE NEW PIPE CONFIGURATION INCREASED THE COUPLING'S AXIAL STRESS. BECAUSE THE EXISTENCE OF THE COUPLINGS WAS NOT NOTED, THE OPERATOR'S PRACTICE TO IMPROVE THE COUPLING'S RESTRAINT SYSTEM, NEAR THE NEWLY INSTALLED 90-DEGREE ELBOW, WERE NOT FOLLOWED AND THE BURIED COUPLING SEPARATED AT NORMAL OPERATING PRESSURE INTO THE PROXIMATE CONSTRUCTION TIE-IN POINT EXCAVATION WHICH WAS STILL OPEN. CORRECTIVE ACTIONS INCLUDE COMPLETING ADDITIONAL ENGINEERING REVIEW OF ACTIVE PROJECTS AND ADDITIONAL TRAINING.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: INCORRECT OPERATION — OTHER INCORRECT OPERATION.

PHMSA indexed costs: $368,978 reported total cost, $203,555.519 in 1984 dollars, $432,190.935 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.