Heavy smoke pours from the debris as firefighters respond to a five-alarm fire and building collapse at 1646 Park Ave. in Harlem on March 12.
Investigators have located a gas leak next to one of the buildings that collapsed during last week's deadly explosion in East Harlem.
The National Transportation Safety Board said Tuesday that an 8-inch cast iron and plastic gas main on Park Avenue between 116th and 117th streets failed a pressure test at the normal operating pressure.
Tracer gas that was pumped into the main pipe and a leak survey led investigators to locate the leak adjacent to 1646 Park Ave.
Two service line segments, 20 feet long and 3 feet long, that were recovered from the basements of the collapsed buildings have been marked as evidence and will be shipped to the NTSB lab in Washington, D.C.
The NTSB said it plans to excavate the leak location to expose the gas main pipe. Segments of the pipe will be cut, removed and sent to the NTSB lab for further testing.
A segment of the cracked water main pipe in front of 1644 Park Ave. will also be sent to the lab, officials said.
Eight people died and dozens were injured when an explosion caused two buildings to collapse about 9:30 a.m. on March 12.
The NTSB also said pressure testing of service lines to the buildings on Park Avenue adjacent to the destroyed buildings "continues with no significant finding to date." Con Edison and the city are working to restore gas service to those buildings.