Report: Faulty Rigging Caused Deadly Crane Collapse

Workers used the wrong kind of slings and attached them in the wrong place to a crane that toppled and killed seven people in midtown Manhattan last year, a city report concluded Wednesday.
    
The city Department of Buildings blamed faulty rigging for the collapse last March 15, which focused attention on construction safety during a string of deadly accidents in the city, including a second tower crane collapse in May.
    
The contractors in charge of "jumping,'' or raising the crane to a higher level on a 19-story condo tower, attached four nylon slings to an 11,000-pound steel brace that was supporting the crane alongside the building, the report found.
    
The crane manufacturer required that eight chain braces should have been used instead of polyester slings, said the report, prepared for the city by an independent consultant. One of the slings was so frayed that it should not have been used and the slings weren't attached at the points specified by the manufacturer, the report found.
    
"Failure of the polyester slings due to improper usage'' caused the steel brace to fall from the 18th floor, knocking out lower attachments and causing the crane to demolish a four-story town house and damage over a dozen other buildings in a quiet neighborhood near the United Nations, the report found.
    
Six construction workers on the crane and a Florida woman in town for St. Patrick's Day weekend were killed.
    
Other probes into the collapse have reached similar conclusions.
 
A federal report blamed the worn sling and rigging; Manhattan prosecutors indicted the rigging company and its CEO in January on manslaughter charges.
    
The two collapses created dozens of new rules for erecting and operating cranes over the city skyline, including a requirement that city inspectors watch rigging procedures and that engineers certify the site beforehand.
    
The report found that the city's inspection protocols at the time wouldn't have found the rigging errors, and also said that some of the permit's requirements are ``confusing and not well-documented.''