Columbia Gas Parent Company 'Fully Cooperating' With NTSB Probe, CEO Says

LAWRENCE (CBS) – The CEO for the parent company of Columbia Gas said at a Sunday press conference that the organization is fully cooperating with the National Transportation Safety Board (NTSB) to determine what caused devastating fires and explosions in the Merrimack Valley.

Related: North Andover Residents Frustrated By Lack Of Answers From Columbia Gas

Joe Hamrock, the CEO of NiSource, said "it's heartbreaking to see this devastation and this tragedy."

On Thursday, dozens of explosions and fires broke out in Lawrence, Andover and North Andover due to an over-pressurized gas line.

"We all express our sincere regret and commitment to restoring lives in the Merrimack Valley in the days and weeks ahead," Hamrock said.

Read: Weeks To Fully Restore Gas Service After Merrimack Valley Explosions

The NTSB is working to determine exactly what caused the incident. On Sunday, NTSB chairman said pressure sensors were connected to a gas line that was being taken out of service on Thursday. The NTSB is looking to find out why.

Hamrock said NiSource is "taking full responsibility for whatever the NTSB findings may be."

He said a restoration plan is being put in place.

"We're in this for the long run," Hamrock said, adding "We know this has damaged the confidence and trust in our company and what we do. Our full commitment is restoring that trust and that confidence."