NEW YORK : Search crews picked through still-smouldering rubble on Thursday, looking for survivors of a gas explosion that caused the collapse of two New York apartment buildings a day earlier, killing seven people and injuring about 60.
Facing thick smoke and bitter cold, dozens of firemen, police officers and a team from the National Transportation Safety Board was at the Upper Manhattan scene to determine what had caused the explosion on Wednesday, shortly after a resident nearby had called utility Con Edison to complain about the smell of gas. The safety board investigates accidents involving natural gas. The debris continued to flare up at times as rescuers clawed through the rubble of the adjoining buildings that had housed 15 apartments on a largely residential block at East 116th Street and Park Avenue.

Passersby wore dust masks or wrapped their faces in winter scarves to limit inhalation of dust and smoke.
Mayor Bill de Blasio said a preliminary investigation indicated the explosion in East Harlem was caused by a gas leak.
Authorities allowed some residents of buildings nearby to return to their homes to retrieve possessions, but many left quickly, complaining of the smoke.
The last time the utility had received a complaint about a gas odour in the neighbourhood was in May, said Consolidated Edison Inc spokesman Bob McGee.
At the time, Con Ed had shut the gas off and the building had hired its own contractor to fix a leak. On July 3, Con Ed crews returned to the building to certify the repairs were done correctly, McGee said.
On February 10 and February 28, there were “high speed” checks made of the gas pipes, he said.