An accident involving a semi-trailer and three Oregon Department of Transportation vehicles has clogged up traffic on westbound Interstate 84 between The Dalles and Mayer State Park. An ODOT spokesman says no one was hurt, but a lot of material was spilled on the freeway at milepost 77, making for lengthy clean-up. Westbound I-84 has reportedly had up to four mile backups since the accident occurred around 10:30 Monday morning. The accident occurred on the inside westbound lane next to the median.