Initial grand jury subpoenas were served to NiSource and its subsidary Columbia Gas of Massachusetts on Sept. 24, according to a NiSource regulatory filing. The company said it is cooperating with the investigation.
Columbia Gas said this week it had replaced about 44 miles of gas mains and more than 5,000 service lines in the Merrimack Valley following the Sept. 13 mishap which killed one resident and left 25 others injured. But it said it would miss its Nov. 19 deadline for restoring service to all of its customers. The company now says the work should be completed by Dec. 16.