Harborview Medical Center in Seattle reports a 29-year-old woman who had been in critical condition died Friday of her burns. Three other workers remain in critical condition at the hospital.
Three people were killed in the blast that shook homes and shot flames into the night sky early Friday at the Tesoro refinery in Anacortes, about 70 miles north of Seattle on Puget Sound.
The blaze occurred while a unit was being brought back online after maintenance. The fire was extinguished in about 90 minutes.
