APTOPIX I-5 Bridge Collapse

A major highway bridge over a river in Washington State collapsed. Officials say they know a little bit about why it happened, but the investigation is far from over.

FOX News Radio's Jessica Rosenthal reports:

I-5 Bridge Collapse

The top of a steel box on an over-sized load semi truck hit the support girders, causing the I-5 bridge north of Seattle to collapse. This bridge is considered fracture critical, which means a failure of just one major structural part of the bridge can do a lot of damage.

APTOPIX I-5 Bridge Collapse

(Phelps) "Even a new bridge struck by a load this size at speed, you could see a catastrophic collapse of any bridge."

Travis Phelps with the State Department of Transportation says they issue permits for over-sized loads, but it's the freight company's responsibility to make sure all of their loads fit through intended structures.

(Phelps) "How did the vehicle hit? What caused the vehicle to hit the bridge? Was it simply a permitting issue? Was is it simply negligent driving? We don't know yet."

He says it will be a while until they can fix it.

Jessica Rosenthal, FOX News Radio.