Two others have minor injuries -- a 45-year-old man who was knocked down has back pain, and a 23-year-old woman was hit in the leg.
All three have been taken to Harborview Medical Center in Seattle.
Fire Department spokeswoman Dana Vander Houwen (HOW'-en) says bricks and concrete from above the Icon Grill restaurant knocked off pieces of a sign as they fell.
Police have blocked off the building until inspectors say it's safe.