The National Transportation Safety Board (NTSB) announced they were investigating the company.
In April this year, NiSource's Columbia Gas of MA filed a petition with the state's Department of Public Utilities to increase annual revenues in order to help the company replace aging infrastructure.
Investigators will also look at how local Columbia Gas officials responded to a "pressure increase" in the Lawrence area that was detected at the company's pipeline control center in Columbus, Ohio, prior to the explosions and fires.
Investigators expect to be on site up to ten days.
A series of gas explosions Thursday killed a teenager, injured about 25 others, damaged dozens of homes and forced the evacuation of thousands in Lawrence, North Andover and Andover.
It appeared yesterday that faulty pressure in the Columbia Gas mains may have caused the explosions, which set 60 houses alight in Andover, North Andover and Lawrence, north of Boston, on Thursday.
Meanwhile, a report of a strong gas odor brought officials back to a part of Lawrence most impacted by the explosions and fires Saturday morning.