VIDEO: Crews have responded to an Andover neighborhood after a "serious" gas leak outside a home. Fire Chief Michael Mansfield said firefighters responded to a home on Bridle Path Road at the request of Columbia Gas shortly before 3 p.m. Grade 1 gas leak, which is the most serious, was declared. Columbia Gas crews conducting a survey of the neighborhood got extremely high gas readings outside one of the homes. “The gas meters on-scene showed natural gas concentrations of approximately 60 percent, which prompted officials to determine that an immediate hazard existed at that location, requiring immediate corrective action,” officials said.