28 cranes like this one are operating on the Tappan Zee Bridge construction site which is the largest infrastructure project in the US. The crane was a new MLC 300 manufactured by Manitowoc Cranes with a 256 feet long boom. At the time of the accident, construction workers were using a vibratory hammer to install pilings, a routine task that is not considered dangerous or challenging.
Officials are investigating the cause of the collapse. They said the wind wasn’t an issue. The operator of the crane stayed at the scene and was tested for drugs and alcohol.
Read more in the New York Times
Picture of some of the cranes on the Tappan Zee Bridge construction Site, Courtesy of Wikipedia