A shot of double-decker construction at the tunnels north end, taken in the spring of 2014.
A shot of double-decker construction at the tunnel's north end, taken in the spring of 2014. Washington State Department of Transportation

Four workers were injured this afternoon in an accident at the north end of the Alaskan Way Viaduct replacement tunnel project.

The Seattle Fire Department responded to the scene, which is near where the tunnel emerges from the ground at its north end—near the Bill & Melinda Gates Foundation and Aurora Avenue North. The Seattle Times reports that the workers fell 25 feet when a wall in an elevator shaft collapsed.

"Thinking of the injured construction workers from today's tunnel accident. Thanks to @SeattleFire for their quick response," Mayor Murray tweeted.

We'll update as we hear more.

UPDATE: WSDOT and Seattle Tunnel Partners now say five workers were involved. STP released a statement this morning, noting that it had begun an investigation into the causes of the incident: "At the SR 99 tunnel’s north portal, Seattle Tunnel Partners is continuing with its investigation of the safety incident involving five ironworkers who were installing rebar for a concrete wall on Thursday afternoon. STP is thankful that four of the workers were not seriously injured. The fifth worker is currently receiving medical treatment at Harborview Medical Center."

UPDATE: KIRO's Libby Denkman reports that one of the workers has a broken arm.

UPDATE: KING 5's Heather Graf reports that none of the hurt workers have life-threatening injuries.