New York ? Scott Bair was on a breakfast break from his construction job Friday when he heard the collapse. He rushed back, dropped his egg sandwich and surveyed the disaster – the mangled wreckage, the smell of smoke, the wails of sirens, a shoe lodged under the debris.

Two construction workers were killed when a crane snapped and smashed into an apartment building, sending residents fleeing for cover. Bair took a roll call of his own crew of 40 workers and discovered one was missing, a man who survived with serious injuries.

“Everyone was shook up and crying,” the foreman said. “These are some hardened men, but they were crying.”

The scene unfolded on the Upper East Side of Manhattan on Friday in an all-too-familiar tragedy for the city. Two months earlier and 40 blocks away, a crane collapse killed seven people, leading to stepped-up inspections and a shake-up in the city Buildings Department.

City officials could not immediately say how the 200-foot crane fell apart as contractors were building a 32-story luxury condo complex.

Mayor Michael Bloomberg called the accident “unacceptable and intolerable” but added: “Having said that, we do not know at the moment what happened or why.”

Acting Buildings Commissioner Robert LiMandri said investigators “will be focusing on a particular weld that failed” on the crane, and noted that the 24-year-old crane’s model, the Kodiak, is out of production and one of only four in the city.

With the city going through a supercharged building boom and an estimated 250 cranes in operation as of mid-March, New York has seen a series of deadly construction accidents.