(MOUNT VERNON, Wash.) — Three people were sent to the hospital after a portion of an Interstate 5 highway bridge in Mount Vernon, Wash., collapsed Thursday, dumping two vehicles and a travel trailer into the icy water, authorities said.
The three people were rescued from the Skagit River by first responders and taken to local hospitals with non-life-threatening injuries.
Officials located a semi-truck believed to have hit several girders on the four-lane bridge just before the collapse. The driver remained on the scene and was cooperating with investigators, Washington State Patrol Chief John Batiste said at a press conference early Friday morning.
“We’re looking at the cause being an oversized, over-height vehicle, striking critical portions of this bridge, causing it to collapse,” said Travis Phelps of the Washington State Department of Transportation and Washington State Patrol.
The National Transportation Safety Board will arrive Friday to investigate the collapse.
The collapse occurred on the portion of Interstate 5 over the Skagit River, about 60 miles north of Seattle.
The vehicles plunged about 40 feet from the bridge into the river, which set off a massive rescue operation.
Helicopter footage from ABC News affiliate KOMO-TV showed several rescue boats in the Skagit River with several ambulances waiting on the shore.
The bridge, built in 1955, was not considered structurally deficient, but was listed as “functionally obsolete” — a category indicating an outdated design, such as having narrow shoulders and low clearance underneath, according to a database compiled by the Federal Highway Administration.
Federal records show it had a sufficiency rating of 57 out of 100, meaning it’s in need of repairs. The bridge was inspected twice last year, most recently in November, and repairs were made, according to Washington Transportation Secretary Lynn Peterson
Clean-up efforts will take several days to weeks, according to Phelps. The bridge sees 77,000 cars per day, and Phelps said they were expecting significant congestion until the bridge is fixed.
Washington Gov. Jay Inslee told reporters that one in five bridges in Washington have a rating of “functional obsolescence,” which he described as “troubling.” Inslee acknowledged the bridge collapse is going to cause a headache for tens of thousands of drivers.
“This is the aorta, the arterial of commerce for western Washington and we will ask all Washingtonians to help us avoid traffic problems,” he said.
I-5 is the longest interstate highway on the West Coast, running from the Mexican border all the way north to Canada.
Copyright 2013 ABC News Radio
Kathryn Vasel, CNN