Seven workers performing demolition work on Seattle's deteriorated Pier 58 had to evacuate the site when a portion of the 1974-built structure collapsed into Elliott Bay Sept. 13.

Five of the workers were able to exit the site and two fell into the water but were quickly removed before the Seattle Fire Department arrived on scene. The City of Seattle says all workers on the pier were wearing personal flotation devices as specified by safety protocols.

The two workers were treated by Seattle Fire medics and transported to Harborview Medical Center in stable condition. Orion Marine Contractors, Inc., the company performing the emergency work, referred all questions to the city. Orion is based in Houston and has an office in Tacoma, Wash.

Pier 58, between the Seattle Aquarium (Pier 59) and Miner’s Landing (Pier 57), which holds the Great Wheel, was slated for replacement in 2022 as part of Seattle’s Waterfront Seattle Program. But on Aug. 6, Seattle Parks and Recreation staff confirmed that the pier had shifted several inches and immediately shut off public access and fenced the site. A digital monitoring system was installed in August to detect movement.

“Piers and other marine structures naturally deteriorate over time,” said Jesús Aguirre, Seattle Parks and Recreation superintendent, in a statement. “We’ve been monitoring this structure for many years in anticipation that it would eventually need to be replaced.”   

Seattle Mayor Jenny Durkan approved a plan for emergency removal of the pier on Aug. 14, following a recommendation from engineering firm Seattle Structural. Orion was hired on Aug. 26 to begin work on the pier. Due to “accelerated deterioration of the pier,” the city announced on Sept. 11 work would extend to seven days a week.

During the partial collapse, the construction team was in the process of removing a concrete section of the pier to delay further pier movement, according to a city spokesperson.

There was no “observed damage” to Pier 59, Pier 57 or the adjacent seawall.

“The city will continue removing Pier 58 as soon as it is safe to do so and will evaluate the best approach, understanding the pier continues to be unstable,” the city said in a statement. “An update on how pier removal will continue will be available later this week.”