Manhattan prosecutors are expected to announce manslaughter charges on Monday against the rigger who was overseeing the raising of a tower crane on the East Side last year when it collapsed, killing seven, according to people briefed on the case.

The rigger, William Rapetti, has also been charged with criminally negligent homicide, reckless endangerment and second-degree assault in the spectacular disaster, in which the 22-story crane plunged across East 51st Street, piercing one building and tearing terraces off another, the people said. The accident, on March 15, played out across a two-block swath of the Turtle Bay neighborhood, leaving two dozen people injured and the streets strewn with rubble.

05fall650

The charges — including seven counts each of second-degree manslaughter and criminally negligent homicide — are contained in an indictment that is expected to be unsealed on Monday, the people said. Mr. Rapetti’s company, Rapetti Rigging Services, will also be charged, the people said. All spoke on the condition of anonymity because the charges remained sealed.

Mr. Rapetti, 48, of Massapequa Park, N.Y., was set to surrender on Monday morning, said his lawyer, Arthur L. Aidala, who noted that five of the seven people who died were friends of his client’s, men working with him on the crane that day.

Mr. Aidala said he was confident that Mr. Rapetti, an expert in the operation and rigging of tower cranes, would be cleared. “He did nothing wrong, and operated at that site in a way that is beyond reproach,” Mr. Aidala said.

The indictment, the result of an investigation by the office of the Manhattan district attorney, Robert M. Morgenthau, represents the first criminal charges stemming directly from a spate of fatal accidents involving tower cranes last year.

Alicia Maxey Greene, a spokeswoman for Mr. Morgenthau’s office, declined to comment on the case.

The March 15 collapse, and a second fatal collapse two months later, led to the resignation of the city’s building commissioner and the arrests of its chief crane inspector, one of his subordinates and a crane company owner on corruption charges unrelated to the collapses — cases that resulted from the scrutiny following the accident.

The second collapse, on East 91st Street on May 31, remains under investigation by the Rackets Bureau in Mr. Morgenthau’s office, the same group of prosecutors that is handling the case against Mr. Rapetti and that brought the corruption cases, one law enforcement official has said.

The two accidents, coupled with a series of disclosures about missteps by city agencies and others in the fatal fire at the former Deutsche Bank building in 2007, exposed the deeply flawed operations of the Buildings Department. In particular, the crane collapses focused attention on the department’s troubled Cranes and Derricks Division, where a handful of inspectors, some lacking in experience, were overwhelmed by the workload brought on by the city’s building boom.

The charges against Mr. Rapetti stem from what one person briefed on the case said were “reckless and negligent rigging practices,” which caused the failure of four nylon slings that were being used to hoist a huge square steel crane component to the top of the crane. The component, called a collar, was being moved to raise the crane higher to continue construction, a process known as jumping the crane.

Mr. Rapetti also failed to follow the crane manufacturer’s specification that the collar be supported by eight slings, the person briefed on the case said.

One sling had “substantial pre-existing damage, including cuts and severe dislocation” that would have been readily apparent to Mr. Rapetti had he inspected it before use, as the building code and federal regulations require, the person said.

When the slings ripped and the collar broke free at the 18th floor, it plunged down the side of the crane, smashing into a second collar and shearing it from the building before landing on top of a third collar near the crane’s base, destabilizing the tower. The weight of the crane’s cab then pulled the tower down.

In September, federal regulators accused Rapetti Rigging Services of failing to inspect the slings, remove a defective sling from service, protect the slings and comply with the crane manufacturer’s specifications when raising or lowering the crane.

Those citations, by the federal Occupational Safety and Health Administration, carried penalties totaling $220,000 and included three willful violations, the most severe issued by the agency.

Mr. Rapetti had been cooperating with OSHA’s investigation, said his lawyer, Mr. Aidala, who added that Mr. Rapetti came from a family of crane operators and had worked on the machines since he was a youth.

He noted that Mr. Rapetti worked at ground zero operating a giant crane from the day after the Sept. 11, 2001, terrorist attack until late that year, a job he won because of his skill and experience.

By WILLIAM K. RASHBAUM, January 5, 2009, NYT.