LATEST: Blaze at Preston garage
Five fire appliances were dealing with the incident in Skeffington Road, Deepdale, and police were called in to put road closures in place.
There were no reports of any casualties.
Firefighters called in police to help with traffic management.
The road was closed near the junction with St George’s Road and motorists were urged to avoid the area.
Road closures were later lifted.
The fire service later tweeted that the incident was being treated at arson.