A crash involving a cement truck and a tanker truck in the northbound lanes of the Maine Turnpike at mile 79 in Lewiston blocked traffic for hours Thursday and forced motorists to detour off the highway.

The crash was reported by the Maine Turnpike Authority at 1:30 p.m. Thursday. The Maine Turnpike lifted its travel alert for the area at 7:08 p.m.

A cement truck crashed into the back of a tanker truck at a bridge on which traffic was already reduced to one lane for construction, according to a spokeswoman for the Maine Turnpike Authority. There was a minor injury in the crash.

The removal of the trucks has been delayed because the tanker’s load of heating oil must be transferred to another tanker before crews tow the damaged truck. The trucks are stuck on the bridge spanning the Androscoggin River. The turnpike has crews working underneath the bridge to strengthen it as part of a planned refurbishment, the spokeswoman said.

Traffic was being detoured off the Maine Turnpike at exit 75 in Auburn and the entrance ramp is closed as well.