NTSB CITES INADEQUATE EXCAVATION SAFETY PROCEDURES AND POOR EMERGENCY RESPONSE IN BRIDGEPORT, ALABAMA EXPLOSION

On January 22, 1999, while digging a trench behind a building at 406 Alabama Avenue, a backhoe operator damaged a ¾-inch steel natural gas service line and a 1-inch water service line. The damage caused two leaks in the natural gas service line. One leak occurred where the backhoe bucket had contacted and pulled the natural gas service line. The other was a physical separation of the gas service line at a joint near the meter, which was close to the building. Gas migrated into the building at 406 Alabama Avenue, where it ignited. The resulting explosion destroyed buildings at 404, 406, and 408 Alabama Avenue.

As a result of this accident the Safety Board has made the following recommendations:

to the Research and Special Programs Administration and the Alabama Public Services Commission:

1. Inform natural gas pipeline operators of the circumstances of the January 22, 1999, accident in Bridgeport, Alabama. Further, advise operators to review their emergency plans and procedures for responding to gas pipeline emergencies and modify them as necessary. The review should determine whether the procedures prompt the appropriate actions for gas leaks caused by excavation damage near buildings and whether the procedures adequately address the possibility of multiple leaks and the underground migration of gas into nearby buildings.
2. Evaluate, during annual inspections of utilities, the adequacy of operator emergency plans and written procedures for responding to gas pipeline emergencies, paying particular attention to procedures that address the possible migration of gas from excavation sites into nearby buildings. If warranted, require that operators modify the procedures.

to the Utilities Board of the City of Bridgeport:

3. Revise your emergency plan and procedures for responding to reported gas leaks, paying particular attention to the possibility of multiple leaks and to the underground migration of gas into nearby buildings from damaged pipelines. In addition, train appropriate personnel in the new procedures, and ensure that they understand existing procedures to secure the area and protect people.

to R&B Construction:

4. Implement and enforce procedures for using one-call before excavating near underground utilities and for safely excavating in the vicinity of underground utility lines, and provide adequate instruction to employees on these procedures.

A recommendation will be drafted for the Alabama One Call Center to inform their members about the circumstances of this accident and the importance of notifying the one-call center prior to conducting excavation activities.

The Board's final report may be accessed on the NTSB website, www.ntsb.gov. Printed copies may be purchased later this winter from the National Technical Information Service (800) 533-NTIS.

NTSB Media Contact: Lauren Peduzzi (202) 314-6100