Some 8,000 people were prevented from returning home in Boston suburbs on Friday as investigators scrambled to find out the cause of dozens of gas explosions that killed at least one person and injured about 12 more.
The blasts on Thursday destroyed scores of homes and other buildings in Andover, North Andover and Lawrence, left more than 18,000 homes and businesses without power and forced thousands of people from their homes.
Investigators suspected “over-pressurization of a gas main” belonging to Columbia Gas of Massachusetts led to the series of explosions and fires, Andover Fire Chief Michael Mansfield said on Thursday.
Massachusetts State Police said around 70 fires, explosions or investigations of gas odor had been reported.
“This has been obviously an incredibly difficult day,” Massachusetts Governor Charlie Baker said in a news conference early on Friday.
Those driven from their homes “should expect that the restoration process will take several days or longer,” Andrew Maylor, the town manager of North Andover, said on Twitter.
National Transportation Safety Board Chairman Robert Sumwalt said it would likely take investigators some time to examine the pipeline’s design, maintenance and upgrades.
“The truth of the matter is we really don’t have any factual information at this point to confirm,” Sumwalt said on Friday.
Columbia Gas, a unit of utility NiSource Inc (NI.N), is investigating, NISource spokesman Ken Stammen said on Thursday. Before the explosions, Columbia Gas had said it would be upgrading gas lines in neighborhoods across the state, including the affected suburbs.
NiSource shares fell more than 9 percent on Friday morning.