The US National Transportation Safety Board said Tuesday that pipeline operators may need improved procedures to inform excavators about the dangers of multiple leaks and the underground migration of gas from damaged pipelines.
NTSB accepted a staff report on a Jan. 22, 1999, pipeline rupture in Bridgeport, Ala. The resulting explosion killed three persons and injured five. Three buildings were destroyed and several others were damaged.
NTSB said a backhoe operator damaged a 3/4-in., 35-psig steel gas service line, enabling gas to migrate into a building.
NTSB said, "The Bridgeport accident illustrates that pipeline operators may need improved procedures to inform utility workers about the dangers of multiple leaks and of the underground migration of gas from excavation sites into nearby buildings."
It blamed R&B construction Co. for rupturing the line during an excavation, and the city Utilities Board's procedures for responding to pipeline emergencies.
NTSB recommended that the Transportation Department's Research and Special Programs Administration and the Alabama Service Commission inform gas pipeline operators about the accident.
It said operators should review whether their emergency procedures cover the possibility of multiple leaks from pipelines and the underground migration of gas into nearby buildings.
It said the city should train its personnel to ensure that they understand emergency procedures to secure the area of an accident and protect citizens.
NTSB said it would recommend that the Alabama One Call Center, which informs excavators about the location of buried utilities, also distribute information about the accident.