Human error may have been the cause of the Seattle tower crane collapse Saturday, killing four people and injuring four others. USA Today reports that experts who viewed video of the collapse suggest that workers who were disassembling the crane may have removed pins holding sections of the crane together too quickly.
“The reason this tower fell over is ironworkers and the people working on it did not follow the manufacturer’s instructions for disassembling the crane,” South Carolina crane accident investigator Tom Barth told USA Today. “If the pins had been in, that crane would not have fallen over."
Two ironworkers on the crane died, identified by King County as Andrew Yoder, 31, and Travis Corbet, 33. Both were in the cab of the crane when it collapsed. Alan Justad, 71, a retired city employee and Sarah Wong, 19, a Seattle Pacific University freshman, died from the crane’s impact.
According to NBC News, Yoder and Corbet were members of the International Association of Bridge, Structural, Ornamental and Reinforcing Iron Workers. The two were ex-Marines who went into construction after leaving the military.