Columbia Gas' Merrimack Valley Accident: Fallout Just Starting

摘要

On Sept. 13, at about 4 p.m. Eastern Daylight Time, a series of explosions and fires erupted in a gas distribution system in the city of Lawrence, Mass., and the nearby towns of Andover and North Andover, about 25 miles north of Boston. The distribution system is owned and operated by Columbia Gas of Massachusetts (Columbia Gas), a subsidiary of NiSource.The consequences were tragic and severe. One person was killed and at least 21 others, including 2 firefighters, were hospitalized. At least five homes and several structures were destroyed, and damage extended to 131 structures. An initial analysis by the National Transportation Safety Board (NTSB) indicated that high-pressure gas was released into a low-pressure distribution system. Most damage resulted from fires ignited by gas-fueled appliances.Preliminary CauseIn a preliminary report dated Oct. 11, the NTSB described how a series of construction and monitoring errors likely led to the disaster. It said Columbia Gas failed to require contract workers replacing century-old pipes in Lawrence to relocate pressure sensors during pipeline work, resulting in over-pressured lines that caused the explosions and fires.