NEW YORK—A Manhattan federal judge has dismissed claims that negligence by developer Larry Silverstein or his subcontractors led to the destruction of the original 7 World Trade Center, the last tower to fall during the Sept. 11, 2001, terrorist attacks.

New York-based power utility Consolidated Edison of New York Co. and its insurers had accused Silverstein's 7 World Trade Center L.P., its architects, engineers and building subcontractors of negligence in the design and construction of the tower as well as diesel fuel tanks installed later by the building's primary tenants, Citigroup Inc., for Citigroup's emergency generators.

In a 23-page decision made Friday, U.S. District Court Judge Alvin Hellerstein ruled that Con Edison's theory of the events that led to the tower's destruction were “too farfetched and tenuous to sustain a claim of negligence,” according to court documents.

A Con Edison substation was located beneath the 47-story 7 WTC tower, which collapsed almost seven hours after the twin towers were destroyed. Fires fed in part by thousands of gallons of diesel fuel burned inside the tower throughout the afternoon, eventually compromising its steel frame.

Three year after the attacks, East Rutherford, N.J.-based Aegis Insurance Co. and several other insurers as subrogates of Con Edison filed suit against Silverstein Properties and others alleging that negligent design and construction of the tower, the diesel tanks or both contributed to the tower's collapse.

The suit alleged that Silverstein Properties, as the building's designer and developer of the tower, had a duty to protect the tower's tenants from harm. However, Judge Hellerstein said that while tenants in the tower could claim a general duty of protection from Silverstein, that duty should not extend to the events of Sept. 11, 2001.

“Con Edison, in order to succeed, must overcome the improbability of a long chain of events, one acting upon another,” Judge Hellerstein wrote, adding that the utility would need to demonstrate the predictability of the entire set of circumstances that caused the building's collapse, including the hijacking of aircraft, the strike on the twin towers and the probability of resulting fires spreading to the 7 World Trade tower.

“I hold that the chain was much too improbable to be consistent with any duty, and I dismiss Con Edison's claims on that basis,” Judge Hellerstein wrote.

A spokesman for Silverstein Properties Inc., the parent company of 7 WTC L.P., declined to comment on the ruling.

In a statement, Con Edison said it would review the decision, but did not say if it would appeal. “This is one of many legal and financial issues involving multiple parties associated with the events of 9/11,” the utility company said in the statement.

Another suit still pending

It was unclear what, if any, impact the dismissal of Con Edison's case against Silverstein would have on a similar suit it has pursued since 2002 against the Port Authority of New York and New Jersey, which owns the tower. Earlier this year, the 2nd U.S. Circuit Court of Appeals reinstated portions of that suit after Judge Hellerstein had tossed it in 2008, based on his reading of specific clauses contained in the utility's original 1968 lease with the authority.

The 2nd Circuit ruled unanimously that the authority could be sued for negligence in the installation of the fuel tanks, which Con Edison alleges, through a faulty design, exacerbated the fire that ultimately felled the tower.