A bridge on Corney Fell has been closed to traffic because it poses a danger to the public.
Buckbarrow Bridge on the U4064 has been damaged and Cumbria County Council has closed it so repair work can be carried out.
The road is often used by workers at the Sellafield site to commute to the plant.
Vehicles are banned 17 metres either side of the centre line of the bridge. The closure came into force yesterday and it is likely the bridge will remain closed for 12 days.
A way for pedestrians and dismounted cyclists will be maintained at all times, the council said. An alternative route for vehicles will be available via the unrestricted sections of U4064, C4028 and A595.
