NEW YORK (AP)  --  A crane dropped seven tons of steel from a skyscraper onto a construction trailer Friday, seriously injuring an architect at the site just across from ground zero.

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The builder of a new corporate headquarters for investment banking giant Goldman Sachs Group Inc. was cited for four violations, including unsafe hoist operations and failure to safeguard the public during construction, after the crane's nylon sling snapped and dropped its load of 25- to 30-foot-long pieces of galvanized steel.

The crane was lifting the metal studs, being used to support shaft walls at the skyscraper's core -- to the 13th floor of the 30-story building before the accident, said Richard Kielar, spokesman for the tower's builder, Tishman Construction Corp.

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The accident, which left architect Robert Wood hospitalized in stable condition, is one of a string of recent serious construction accidents in the city. A window washer was killed and his brother critically injured when a scaffold plummeted more than 40 stories off a building a week ago. A worker was killed the same day in the Bronx after heavy equipment pinned him while he was digging a hole to lay connecting pipe to a city water main, officials said.

The city Buildings Department on Friday issued a stop-work order for the crane at the site and cited Tishman Construction Corp. and the contractor leasing the crane, DCM Erectors Inc., for unsafe hoisting operations.

Tishman -- the builder of Goldman Sachs -- was also issued violations for failing to safeguard the public, failing to provide toe boards that prevent construction workers from accidentally falling off and failing to maintain netting along the sides of the building.

The sling was carrying a 14,000-pound load and is designed to carry 19,000 pounds, the department said.

Kielar said in a statement that a "material failure that ... could not have been foreseen'' may have caused the incident.

"Our safety record on this project, in general, is excellent by industry standards,'' he said. "The on-going safety of the community and of personnel on this site and on all Tishman sites is of paramount importance to us.''

The $2 billion tower, just across the street from the signature Freedom Tower being built to replace the World Trade Center, was considered a crucial anchor to the redevelopment of downtown Manhattan after the 2001 terrorist attacks.

After agreeing to become the first major firm to relocate its world headquarters near the site, the bank changed its mind, saying it had security concerns about a tunnel that was to be built at ground zero which would face it.

In 2005, state and city officials agreed to pay Goldman Sachs $1.65 billion in tax-exempt Liberty Bonds and offered millions in other incentives for the firm's commitment to move downtown. Politicians later said they would never offer as lucrative a deal again for companies seeking to move downtown, but that the Goldman Sachs deal was warranted because the company inspired confidence in the area.

The planned 43-story tower is expected to house 9,000 of the company's employees when it opens in 2009.

Photo from Gary Baumgarten/Paltalk