Updated: 7:27 p.m. E.T.
As rescue workers spent Thursday looking for the source of the gas leak that caused an explosion in New York City that killed at least eight people, the National Transportation Safety Board said the gas main and distribution pipes under the streets were intact.
More than 60 people were injured during the blast that took down two five-story apartment buildings in East Harlem on Wednesday. Some tenants claim that the apartments had smelled of gas for weeks, but fire and utility officials say nobody reported the smell until Wednesday.
A more extensive inspection of water and gas lines will take place once rescue efforts have subsided. "We can only get conclusive evidence when the fire is out, when the rescue is completed, and we really get a chance to look at all the facts," New York City Mayor Bill de Blasio said.
The unknown cause of the accident has New Yorkers worried about the aging infrastructure in the city. The cast-iron gas main servicing the two buildings dates back to 1887.
This story was updated to reflect the rising death toll.