Guernsey's Fire & Rescue Service are dealing with an 'outside fire' at the plant in St Sampsons.
Bulwer Avenue is closed in both directions. The Fire Service is asking people to avoid the area.
Traffic travelling northbound is being redirected down Les Grandes Maisons Road. Southbound traffic from The Bridge is being diverted along Nocq Road and Saltpans Road.
Follow Charlie Frost for latest updates.