EDMONDS, Wash. -- A propane tank exploded at the Picnic Point Wastewater Treatment Plant in Edmonds Thursday, injuring five people.
The plant is located at 6315 Picnic Point Road, in the area of Picnic Point Elementary School.
According Snohomish County firefighters, the explosion occurred around 11:00 a.m. as a 1,000 gallon propane tank was being loaded onto a truck. About 300 gallons of propane remained in the tank, when it shifted and a valve was severed, causing the truck and tank to explode.
"The truck driver realized what happened right away and told everyone to get away and then the explosion occurred," said Leslie Hynes of Snohomish Fire District 1.
Five workers at the plant were burned in the explosion. All of them were transported to Harborview Medical Center. One of the workers has been released from the hospital. Three of them are in satisfactory condition, and one remains in critical condition with non life-threatening injuries.
Fellow workers say they raced to the area to find their colleagues dazed but were able to get everyone else out safely.
Firefighters spent most of the afternoon dousing the tank and truck with water. Initially after the explosion, black smoke billowed from the tank, towering high above the building
The fire also spread to a construction trailer, as well as two buildings that were under construction. Throughout the day, small brush fires continued to spark in nearby woods close to the site of the explosion.
Officials said the plant, which serves 175,000 customers in undergoing a $90 million expansion that was to be completed later this year.