HOUSTON—A NiSource Inc. affiliate failed to require contract repair crews to relocate pressure sensors during natural-gas pipeline work, the National Transportation Safety Board (NTSB) said on Oct. 11, resulting in overpressured lines that caused explosions and fires in three Massachusetts communities last month.
Overpressurized gas poured through Columbia Gas Co. of Massachusetts’ distribution system in Lawrence, North Andover, and Andover, flooding into homes and businesses, and sparking explosions and fires that killed one person and injured 21.
