Rescue workers are using back hoes and a bulldozer to search for any victims still buried after an explosion demolished two Manhattan buildings. Meanwhile, questions are swirling about the gas leak that triggered the blast and whether complaints about gas odors had been ignored.

The explosion Wednesday morning killed at least seven people and injured more than 60, with searchers still trying to locate others. At the site on Park Avenue and 116th Street, thermal imaging cameras are being used to identify heat spots — bodies or pockets of fire.

Gusty winds, cold temperatures and billowing black smoke are making the search for additional victims of an East Harlem explosion even more difficult.

The air Thursday morning was thick and acrid. Police guarding the scene wore surgical masks and residents covered faces with scarfs.

FDNY officials say they’re trying to identify exactly what types of debris are still burning.

An FDNY official says the scene of the deadly explosion is “very terrible and traumatic.”

Spokesman Jim Long says the job of sifting through mounds of debris in search of additional victims is difficult and challenging.

Rescuers at the 116th Street and Park Avenue site worked overnight under generator-powered lights.

Acrid smoke, high winds and cold temperatures Thursday were making the job even more difficult.

(AP)