 The United States National Transportation Safety Board (NTSB) – which has responsibility at the Federal government level for investigating accidents involving pipelines and the transportation of hazardous materials – said that natural gas was found in nearby soil in varying concentration.NTSB Board member Robert Sumwalt also revealed that the gas main buried under Park Avenue near the scene at 116th Street dated back 127 years, to 1887.Bricks, wood, and other debris landed on the adjacent elevated Metro-North Railroad tracks, suspending service to and from Manhattan for most of the day while crews cleaned up the mess.