Fifty firefighters are tackling a blaze in a woodyard in Wisbech.
The fire on Brigstock Road is sending thick black smoke into the air.
Cambridgeshire Fire are asking people to avoid the area so crews can do their work. People living nearby have been asked to close their windows because of the smoke.
They say the building contains a lot of wood and they are working to contain the fire and stop it spreading.
The fire is reported to be in an industrial building belonging to Shire who have been producing garden buildings since 1981.
Originally the company produced yachts but later switched production to sheds.