Emergency services are dealing with a building fire at Glasson Industrial Estate in Maryport.
The A596 road is closed between Flimby and Maryport and services on the Cumbrian coast line between Carlisle and Barrow-in-Furness have been cancelled.
Local diversions are being put in place including on a back road via Flimby, Broughton Moor and the A594.
Eight fire engines are at the scene and nearby buildings are in the process of being evacuated.
Police were called to reports of the incident at 1.38pm.
Members of the public are asked to stay away from the area at this time and residents in the Maryport area are asked to keep their windows closed due to the level of smoke.