A double-tanker truck flipped on Interstate 84 westbound early Thursday morning, causing a major traffic backup.

KGW Photo

Traffic was backed up for miles as crews worked to clear the wreckage of the flipped tanker truck.

The driver of the truck, 36-year-old Francisco Macias, told police he swerved to miss a car after it cut in front of him in traffic and as he swerved, he struck an abandon vehicle on the side of the roadway.

"The abrupt movement caused the load of milk to shift in the container, overturning the truck," explained Sgt. Brian Schmautz with the Portland Police Bureau.

The rear tank was damaged, spilling hundreds of gallons of milk all over the Interstate.

Authorities closed all the wesbound lanes of traffic at NE 122nd Avenue just before 9 a.m., so a tow truck could right the tanker. Traffic was already backed up for miles because all but one lane had remained closed since the accident. By 11 a.m., the interstate was re-opened.

 RAW VIDEO: Tanker crash scene

Marcias works for Milky Way Corporation of Sunnyside, Washington. He was not injured and no citations were issued by police, Schmautz said.

No other vehicles were involved in the crash, which occurred just before 6 a.m.