Major Accident (Frisco/Plano)

Multiple Frisco and Plano Fire/EMS units and DPS troopers are on scene of a major accident on Sam Rayburn Tollroad/121 between Preston Rd. and the Dallas N. Tollway. Reported as at least one vehicle and semi truck involved. Vehicles on both sides of the roadway. Command has requested HazMat response. One patient with serious injuries. Lanes blocked on both sides of the roadway. Avoid this area.