Democratic U.S. Senators Elizabeth Warren and Edward Markey sent a letter to Columbia Gas and demanded that six of their questions be answered by Thursday By Monica Madeja and Karla Rendon-Alvarez   As Merrimack Valley residents question when gas will be restored to their homes, lawmakers are demanding answers from Columbia Gas. Columbia Gas, the … Continue reading NECN: Sens. Warren, Markey Demand Answers From Columbia Gas in Wake of Explosions