The A1(M) northbound near Wetherby has been closed this morning after a crash involving three vehicles.
Recovery vehicles are now on their way and crews are treating spillages, which is one of the reasons traffic was held up.
West Yorkshire Police were called at 6.49am this morning to reports of a collision involving a black Vauxhall van, a blue Peugeot and another vehicle.
It happened between junction 45 BostonSpa and junction 46 Wetherby.
There are no further details on injuries, but the incident is believed to be serious,
Police are warning people to avoid the area.
According to AA: "There is a detour in operation - exit at J45 and follow the 'hollow square' symbol."