Abstract: A tool and method for plugging a service connection to a gas main in preparation for removal of the service tee removes the perforator, mills the hole in the main to provide a smooth seat for a sealing plug, and inserts a gas-tight sealing plug into the hole. The tool of the invention is operable through a narrow "keyhole" excavation, which decreases the risk to service personnel and significantly reduces costs of repairing the excavation. In the preferred embodiment the tool is loaded with a milling bit and a sealing plug before attachment to the service tee. The tool head is engaged to the service tee in a gas-tight fit to prevent the escape of gas during the procedure, and an adapter plate is pivoted between three working positions to perform the three steps of the service connection plugging method.