BOSTON (CBS) – Eversource Energy has officially taken over Columbia Gas of Massachusetts, the utility company at the center of the Merrimack Valley explosions.

Columbia Gas accepted responsibility for the 2018 disaster, when over-pressurized pipelines caused explosions and fires in Lawrence, Andover and North Andover.

A federal judge ordered Columbia Gas to pay a $53 million fine and sell the company.

Eversource paid $1.1 billion to purchase the natural gas assets of Columbia Gas in Massachusetts.

With state and federal approval of the transaction finalized, Eversource now serves more than 600,000 natural gas customers in 110 communities across Massachusetts. Columbia Gas previously served 330,000 natural gas customers in more than 60 communities in the state.