On January 3, 1998, at 1635 hours Pacific standard time, a Cessna 210, N9406X, was substantially damaged when it collided with a telephone pole and two cars during an off-airport, emergency landing at Compton, California. The private pilot and one passenger received minor injuries. Visual meteorological conditions prevailed for the personal flight which originated at Long Beach at 1627. The pilot reported that the engine started "popping" and lost power while at 1,500 feet agl on approach to the Compton airport. He did not have sufficient engine power to reach the runway and landed on the city street about 2 miles east of the airport. Examination of the aircraft by the Safety Board revealed an abraded solid aluminum fuel line between the fuel selector valve and the engine. When the fuel selector valve was turned on, a knife-shaped stream of fuel emanated from the line. When viewed with an inspection mirror, the abraded area appeared V-shaped (grooved) and there was a hole approximately 1/16-inch diameter though the wall of the tube at the deepest part of the groove. Dried, crusty fuel stains were present on the fuel line over a distance of approximately 2 inches. The line was under the floor of the cabin, forward of the right front passenger seat, and aft of the firewall. Adjacent to the area of the leak there was a BNC-type antenna connector on an unused marker beacon antenna mounted on the lower fuselage. The pilot involved in the accident had recently purchased the aircraft. An annual and pre-buy inspection was performed on the aircraft 2.6 months prior to the accident. According to the hangar proprietor, the aircraft had leaked fuel onto the hangar floor since some time before the inspection. The previous owner of the aircraft turned the fuel off at the fuel selector valve to stop the leak.