SEATTLE (AP) - Experts say it appears human error may have caused a crane collapse that killed four people and injured four others in Seattle over the weekend.
Based on videos of the collapse, they say it appears workers who were disassembling the construction crane had removed pins securing the sections of the crane's mast to each other, and that could explain why the crane toppled in relatively minor wind gusts.
South Carolina crane accident investigator Tom Barth said the only safe way to disassemble a tower crane is to hook up the section being removed to another crane, and then remove the pins from that section only. In this case, he says, it appears the workers removed pins from all of the sections in advance.
The same cause was blamed for a crane collapse that killed two workers in Dallas in 2012.
An Oregon ironworker and former Marine has been identified by a labor union as one of the four people killed when a construction crane collapsed in Seattle over the weekend.
Iron Workers Local Union 29 based in Portland, identified him as Travis Corbet.
His wife Samantha Corbet told Seattle television stations that her husband had served in the U.S. Marine Corps for five years before becoming an ironworker.
They married last year and planned to go on their honeymoon in June.
Another ironworker killed in Saturday's accident was a member of Iron Workers Local 86, based in Seattle.
Officials say the crane was being disassembled when it fell from a building on Google's new Seattle campus.
It badly damaged the building and struck six cars below.
The ironworkers were in the crane when it fell. The other two people killed were in cars.
Seattle Pacific University said Sunday a freshman student was among those killed when the crane fell from a building under construction on Google's new Seattle campus onto Mercer Street.
The university said in a statement that Sarah Wong was a freshman who intended to major in nursing and lived on campus.
The university says Wong was in a car when the crane fell.