VIDEO: The utility company blamed for natural gas explosions and fires in Massachusetts' Merrimack Valley last September responded to a possible over-pressurization of their lines in Monson Tuesday afternoon. According to the police department, Columbia Gas workers were dispatched to the town to check the infrastructure but said there were no ongoing safety concerns. "You will see Columbia Gas employees surveying the area in the next 1-2 hours. We assure you the area is safe, and we will continue to provide you with updates," the company said in a tweet. The Monson Fire Department said it had fire crews on standby. Firefighters said they checked out a report of a gas smell at 48 Main St. and the gas levels checked out OK.