A Smethport man was injured Saturday night in a tractor trailer accident on Route 46 in Norwich Township. Police say the truck, operated by 46 year-old Mark Carlson struck a guardrail, went down an embankment and struck a tree. Carlson was extricated from his rig and flown to UPMC Altoona for treatment of serious injuries. The Pennsylvania Department of Environmental Protection was called in after an oil-base substance, which was being hauled by Carlson’s tractor trailer, spilled onto the roadway.