The National Transportation Safety Board has determined that the probable cause of a natural gas explosion and fire in Bergenfield, NJ, on December 13, 2005, was the failure of a service company to adequately protect a natural gas line while excavating a fuel storage tank. During the excavation, shifting soil resulted in damage to the service line and the migration of natural gas into a nearby apartment building.
Contributing to the accident, the Board said, was the gas company's failure to conduct effective oversight of the excavation and to be prepared to promptly shut off the flow of gas after the service line was damaged.
Additionally, the Board found that the Bergenfield Fire Department's failure to evacuate the building, despite the strong evidence of a gas leak, contributed to the casualties in the accident.
"Excavation damage continues to be a significant cause of dangerous gas pipeline explosions," said NTSB Chairman Mark V. Rosenker. "There is a need for greater vigilance in preventing these accidents, and for increased emphasis on training service workers and first responders to deal with these emergencies when they unfortunately do occur."
Investigators found a break in the 1 1/4-inch service line at an underground connection downstream from where excavators were removing a 5,000-gallon fuel oil tank that was buried under an asphalt parking lot adjacent to the apartment building. Workers told investigators that the ground surrounding and supporting the pipeline had collapsed. Three residents of the building were killed; four other residents and a service company worker were injured. The building was estimated to be a total loss.
As a result of its investigation, the NTSB made the following safety recommendations:
To the New Jersey Department of Community Affairs:
Establish a requirement that all career and volunteer firefighters receive recurrent training on natural gas safety and incident response.
To the Borough of Bergenfield:
Establish and implement written operating procedures for responding to natural gas incidents and emergencies.
To the American Tank Service Company:
Establish and implement written procedures for safe excavation near pipelines, and provide initial and recurrent training on these procedures to employees.
To the Public Service Electric and Gas Company:
Modify your excavation damage prevention program and emergency plan to require site-specific risk assessments of excavators' plans, and implement procedures to effectively manage the risk, such as increased surveillance of excavator actions to protect the pipeline and ensuring that gas shut- off valves are tested so that they can be closed promptly if the pipeline is damaged.
To the International Association of Fire Chiefs:
Notify your members of the circumstances surrounding the December 13, 2005, accident in Bergenfield, New Jersey, and urge them to establish and implement procedures for emergency responders to rapidly assess situations involving natural gas leaks and to determine whether prompt evacuations are warranted.
To the Pipeline and Hazardous Materials Safety Administration:
Make the recipients of PHMSA emergency planning and response grants aware of the circumstances of the Bergenfield, New Jersey, accident for use in training on natural gas safety and incident response (to be edited).
A synopsis of the Board's report, including the probable cause and recommendations, is available on the Board's website, www.ntsb.gov, under "Board Meetings." The Board's full report will be available on the website in several weeks.