Update: The OPP say Highway 401 eastbound has reopened. Police say there may be lane restrictions later for removal of one transport. 

The OPP say they are investigating a fatal collision on Highway 401.

Police say the collision involves two transports. Highway 401 eastbound between County Road 2 and Stewart Boulevard is still closed, according to OPP.

The OPP is reminding the public to follow the marked emergency detour routes.