At least two people died in a chain-reaction crash involving two tractor-trailers and two passenger vehicles in the northbound lanes of Interstate 81 Wednesday afternoon. The crash happened about two miles south of the Frackville exit and brought Northbound traffic to a standstill. State Police at Frackville said a northbound tractor-trailer ran into a passenger vehicle, pushing that vehicle into a pickup truck, and the pickup truck into a second tractor-trailer. One of the passenger vehicles burst into flames killing two people inside. The truck driver was flown to a trauma center suffering from burns related to the crash. Firefighters from Frackville and surrounding communities responded to the call to extinguish the fire and assist at the scene. Fire police were dispatched to close the road at exit 116, Minersville. State Police at the scene said the northbound lanes will be closed for several hours.