SEATTLE (AP) — Human error may have caused a crane collapse that killed four people and injured four
others over the weekend, experts said Monday.
Based on videos of the collapse, they said it appears workers who were disassembling the construction
crane had prematurely 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.
"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," said crane accident investigator Tom
Barth. "If the pins had been in, that crane would not have fallen over."
The crane’s mast fell over on Saturday afternoon as workers were taking it apart. Sections landed on top
of the new Google building where it had been used and on traffic below, striking six vehicles. Two
ironworkers on the crane were killed, as were two people in cars — a retired city employee and a college
freshman. Four others were injured.
Barth, who has been a tower crane operator, inspector and accident investigator for 38 years, said the
only safe way to disassemble a tower crane is to do it by sections.
First, a line from another crane is secured to the top of the section being removed. Only then do workers
remove the bolts that secure the section being removed to the one below it. The second crane lowers the
section, Barth said.
The videos, including one from a dash camera in a car approaching as the crane fell, appear to show the
sections of the tower crane separating cleanly, indicating the pins had likely been removed early, said
Dave Kwass, a trial attorney who handles crane accident lawsuits.
"Where I would be starting as an investigator is getting a better grasp of what these two
ironworkers who tragically were killed may have done in removing the pins," Kwass said. "What
I’m seeing is a crane that looks as though the pins were popped all the way down to the pedestal
section."
Kwass also suggested that the shifting weight of the workers at the top of the mast as they tried to grab
the wind-swayed hook and line from the other crane might have helped push the mast over.
Early pin removal was blamed after a tower crane mast collapsed during disassembly in Dallas in 2012,
killing two workers. Terry McGettigan, a tower crane specialist in Seattle, declined to comment on
Saturday’s crash, but he wrote a paper on the Dallas collapse warning about the danger of taking
shortcuts by loosening or removing the bolts in advance.
The Iron Workers Union Local 29 based in Portland, Oregon, and Local 86, in Seattle, who represented the
workers who died, did not respond to requests for comment Monday.
Washington Department of Labor and Industries inspectors were expected to finish their work at the scene
Monday, said Tim Church, a department spokesman. He said it was too early to speculate on a cause.
The department on Monday expanded its investigation to include a fifth company: Seaburg Construction
Corp., which employed the tower crane operator. The other companies are general contractor GLY,
Northwest Tower Crane Service Inc., Omega Rigging and Machinery Moving Inc., and Morrow Equipment Co.
LLC
"GLY and its sub-contractors involved with this tower crane accident are doing everything we can to
investigate the incident," the company said in a written statement. "We are cooperating fully
with investigators and assisting the local authorities. At this early stage of the investigation, we
have no further details."
The ironworkers who died were identified by their unions as Andrew Yoder, 31, of Washington, and Travis
Corbet, 33, of Oregon. Corbet’s 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.
Also killed were Seattle Pacific University freshman Sarah Wong, 19, and Alan Justad, 71, who retired in
2014 as deputy director of Seattle’s Department of Planning and Development.
In a written statement, Mayor Jenny Durkan called Justad "a true public servant."