Warren F. Levenberg of Vienna, Va., was killed today as he walked across 53rd Street in midtown Manhattan when a crane collapsed on a building under construction, shattering granite and glass and sending debris 43 stories to the street.

"I was coming out of the subway, walking down 53rd," said Robert Crowder, a businessman.

"I heard the noise, and at first I thought it was a bomb. Because I thought it was a bomb I looked first behind me, then I saw someone had gotten hit in front of me. Something told me to pull him into the building, but at that second I realized he was dead."

Police identified the victim, who leaves a wife and two children, as Levenberg, 31, a comptroller with Ringling Brothers-Barnum & Bailey circus.

Eight other pedestrians were injured in the accident and were taken to hospitals, while perhaps a half dozen, injured slightly, refused medical aid.

There was also the problem, as the day progressed, of additional danger: the 137-foot red crane that fell, smashing the granite on the side of the building, still dangled over the edge of the 43rd story at 5 p.m.

Streets were cordoned off and neighboring buildings were evacuated as police, fireman and construction executives gathered to deal with the problem of removing the crane.

At one point a helicopter, considered as a way of removing the crane, hovered over the site. Below, the windows of the building, which swells at the lower floor, were smashed and broken, as if there had been a bomb.

Spokesmen for the construction manager of the building, Tishman Construction, were unable to provide an explanation for the accident, saying that an investigation was under way.

They said the accident occurred while a subcontractor, Titan Marble and Stone, had been in the process of lowering the boom to dismantle the erection crane used in construction.

In Washington, Kenneth Feld, one of the owners of Ringling Brothers, said he knew Levenberg as a business associate, that he was "a young, good-looking guy with a mustache" and "a very, very hard worker."

Feld was informed of the accident by Charles Smith and Frank Heltai, two of Levenberg's business associates who were walking with him when he was killed.

Injured and slightly shaken, they called from a New York Hospital. Feld broke the news to the Levenberg family.

He characterized the two surviving employes as "shocked. How else would you expect them to feel?"

"It's all very shocking," he said. "Who would expect any risk when you're walking down the street?"