Gas line noise prompts calls to 911 MONROE - A loud explosion heard by many residents Monday night was the result of emergency repairs being performed on a natural gas line. Police, firefighters and first aid officials responded to the area of Grace Hill and Spotswood-Gravel Hill roads at 7:20 p.m. after residents called 911 about a loud noise, which some described as an explosion or even an aircraft accident. Responding officers learned however that New Jersey Natural Gas was performing an emergency repair on a gas line, and the loud noise was the sound of gas escaping from the line, according to township police. The company said this was a noise issue only, and that the release of the gas was not a threat to anyone in the area of the repair. New Jersey Natural Gas issued a statement Tuesday apologizing to residents for the disturbance and explaining the emergency repair. The company had been performing scheduled maintenance on Monday when workers "observed an anomaly" that required immediate action. "At that time, we first attempted to complete the repair by lowering the pressure in the line, but found that we needed to isolate and purge this section completely," the company said in the statement. "Our specialized personnel were on site at all times during the controlled release, and the repair was completed without any service interruption or threat to public safety." Monroe police said the company failed to notify them in advance of the repair, and the township contacted New Jersey Natural Gas Tuesday to ensure that the police department is notified of future repairs so that it can inform residents.