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All lanes are open on southbound Interstate 5 following a semi-truck accident that blocked traffic for hours during the morning commute.

An accident involving a truck with a double trailer closed all southbound I-5 lanes through downtown Seattle, causing a 7 mile backup into the city.

The Washington State Patrol said speed was a factor and the drive will be cited for “going too fast for the conditions of the roadway.”

“He was coming off of dry pavement and onto the wet roadway, so that seemed to be what caused the vehicle to lock up when he hit the brakes,” explained Trooper Julie Judson.

The FedEx truck apparently hit an abutment around 4:30 a.m. Wednesday and was crushed by one trailer as the other trailer tipped. The truck caught fire and was extinguished by firefighters with foam.

KING 5’s Jake Whittenberg told Seattle’s Morning News the truck’s trailers were empty at the time of the crash.

The truck driver is OK. Whittenberg said he was able to crawl out of the truck through a broken windshield. He has spoken with investigators about the crash.

Crews were able to upright the second trailer, but KIRO Radio reporter Chris Sullivan said the trailer closest to the cab was jammed against interstate barriers and resting against one of the support structures of the Spring Street overpass.

As crews started to pull the second trailer from its position, Sullivan said it began to crumble and diesel fuel began leaking onto the road.

The Department of Ecology was on scene to deal with any hazards related to fuel spills.

Crews had to also replace a jersey barrier and clean up fuel from the accident.

The crash blocked the freeway between the Washington Sate Convention Center and I-90 and traffic was detoured at the James Street exit through downtown Seattle. Highway 99, 15th Ave. NW through Ballard, and Roosevelt were very slow in most spots.

WSDOT said about 7,000 cars travel through that portion of southbound I-5 during the peak morning commute.

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The Associated Press and MyNorthwest.com staff contributed to this report.