LAWRENCE (CBS) – An investigation is underway into why a gas line caused massive explosions and fires in the Merrimack Valley. Dozens of homes in Lawrence, Andover and North Andover were destroyed.

An explosion at 4:30 Thursday afternoon is believed to have triggered many more along a natural gas pipeline run by Columbia Gas. It wasn’t until about five hours later that Columbia released a statement on the situation.

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At a press conference after his department extinguished 38 fires, Andover Fire Chief Michael Mansfield said he had not yet heard from Columbia.

“We were unaware for quite a while as to what was going on and we were notified that there was a potential these fires as being promulgated as a result of over-pressurization of a gas main,” Mansfield said. “We have not been able to confirm that, we have not yet spoke to anybody from Columbia Gas to confirm that and we are waiting to get updated from them as we speak.”

Firefighters fight flames at a Lawrence home after gas main problem. (WBZ-TV)

Thursday evening Governor Charlie Baker described the utility’s response as “adequate.”

“There’s a lot more work that’s left to be done,” Gov. Baker said. “If you were to ask me to give a grade I think for all of this at this point it would be incomplete, there’s a lot more to do.”

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At a second press conference early Friday morning the governor said he wanted to, “make clear to the utility company they must immediately bring in additional resources, and develop a comprehensive safety inspection plan for each of these communities.”

At least 80 technicians from Columbia were dispatched into the communities at the time, as part of teams going door-to-door to shut down service.

“We’ll work with the federal government and others to investigate how this occurred and to hold the appropriate parties accountable for their actions,” Baker said.

Rep. Seth Moulton appeared frustrated Thursday night, saying parts of North Andover look “like a war zone.”

“Homes literally exploding and people don’t even know exactly why,” Moulton said.

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Moulton said on Twitter that he called the president of Columbia Gas, but did not get an answer. “Everyone wants answers,” Moulton tweeted. “And we deserve them.”