The Oregon State Police says the cause of a rolled over semi-truck and trailer that blocked Interstate 84 between Hood River and The Dalles on Wednesday afternoon was apparently a blown tire.  According to the OSP report, the truck with license plates from Ontario, Canada was westbound on I-84 near milepost 76 in the right-hand lane when the front left tire blew, causing it to swerve across the left lane and hit the concrete barrier, and then it rolled over onto its side with the trailer sliding on top of the barrier for about 300 feet before coming to a stop, blocking the left lanes of the freeway in both directions.  Traffic on both sides of the freeway was diverted around the crash at exit 76 for several hours.  The truck driver had a few scrapes and cuts but refused medical transport.  The semi-trailer was loaded with 38,000 pounds of Kitty Litter.