Crews were alerted to the blaze on Patterson Street in Blackburn at around 3am on Thursday, September 28.
And firefighters from Blackpool and Preston are helping with the effort to bring the fire under control.
The fire has issued a large plume of smoke is thought to involve plastics and recycling materials.
Nearby residents have been evacuated to a nearby community centre over fears that the smoke may be toxic.
Residents who have remained in their homes are advised to keep their windows and doors closed.
A spokesman for Lancashire Fire and Rescue said: "The building is approximately 160 metres by 100 metres contains plastics and recycling waste.
"There are 10 fire engines and an aerial ladder platform at the scene and firefighters are using water from the nearby canal to extinguish the fire.
"Local residents have been evacuated to Ivy Community Centre and other residents not evacuated have been told to stay indoors and keep windows and doors shut.
"Several local roads have been closed and they will be closed for the next few hours."
Fire services say that no injuries have been reported and they expect to remain at the scene for most of the day.
The cause of the fire is under investigation.