Nashua Fire Rescue responded to Woodward Avenue at Kinsley Street for a natural gas leak. An excavator digging in the street to replace the water main hit and severed a 2 inch low pressure gas supply line. Crews from Engine 2 and Engine 6 stretched an 1 3/4 inch hose line and a 4 inch water supply line to standby as a precaution. The occupants at 150 Kinsley Street were asked to leave the building until the gas was shut off. We monitored air quality in 150 Kinsley Street and 5 Woodward Avenue. There were no gas readings in these buildings. Liberty Utilities arrived and shut the gas off and repaired the line.