Trench collapse at Skookumchuck wind project near Olympia kills rescuer, injures colleague

What happened

During construction of the 136MW Skookumchuck wind project near Olympia, Washington, a 15-foot trench partially collapsed while a worker was inside positioning a bore pipe, trapping him. A colleague jumped in to help but was then trapped by a second, larger collapse. A third worker raised the alarm and a rescue effort involving up to nine people followed, but the rescuer, who worked for a third-party labour agency, was pronounced dead at the scene.

The worker involved in the original collapse was taken to hospital with serious injuries. The Washington State Department of Labor and Industries investigated and said the trenching had been carried out at that depth in winter after days of rain, in unstable soil and with no trench box. In July 2020 it issued fines totalling more than $500,000 against developer RES, its affiliate RES System 3 and a medical services contractor, citing willful violations.

RES said it was heartbroken by the circumstances, that it had fully cooperated with the investigation, and that it strongly disagreed with the alleged violations and would contest the citations, so the penalties were not final at the time of reporting.

Contributing factors

The regulator found that trenching at this depth was carried out in unstable, rain-saturated soil during winter without a trench box, and said RES System 3 had regularly disregarded its internal safety policies and procedures and given inadequate direction to a crew doing inherently dangerous work. These are the regulator's findings and were being contested by RES.

Lessons learned

1. Trench boxes or shoring are required at 15-foot depth in rain-saturated soil to prevent collapse.
2. Untrained entry into a collapsed trench can cause a second collapse and further casualties.
3. Principal contractors must verify that crews follow written safety rules on site.

More lessons on structural integrity and turbines, worker safety and safe systems of work, from every incident on the register.

Not yet known

• Final penalties after contest
• Confirmed cause of the collapses
• Duration of project delay

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Source

Recharge (rechargenews.com)