Con Ed said it remains to be seen whether the leak was in a company main or in customer-installed inside plumbing. The gas main that serves the area was made of plastic and cast iron, and the iron dated to 1887, Foppiano said.
"Age is not in and of itself an issue with cast iron," he said, noting that Con Edison has a cast iron replacement program and the pipe was not slated to be removed in the next three-year period.
A National Transportation Safety Board team arrived in the evening to investigate. The agency investigates pipeline accidents in addition to transportation disasters.
NTSB team member Robert Sumwalt said investigators would be looking at how Con Edison handles reports of gas odors and issues with the pipe and would be constructing a timeline of events.
Just before the explosion, a resident from a building next to the two that were destroyed reported smelling gas inside his apartment and thought the odor might be coming from outside, Con Ed spokesman Bob McGee said.
On Wednesday night, the American Red Cross served meals to more than 130 people living in seven buildings impacted by the blast. The Salvation Army provided accommodations in one of its shelters.
The explosion destroyed everything Borrero's family owned, including the ashes of his father, who died a few years ago. Borrero said he assumes his 5-year-old terrier, Nina, was killed.
But "I have my mother and sister," he said. "I'm happy for that."
Associated Press writers Julie Walker, Verena Dobnik, David B. Caruso, David Crary, Leanne Italie, Meghan Barr and Mike Casey contributed to this report.