Around 40 firefighters have been battling a blaze in a recycling plant near Preston this morning.
Six crews from Preston, Penwortham, Bamber Bridge, Fulwood, Longridge and Blackburn were called to the incident at the premises of Sita Waste Management on the Red Scar Business Park at shortly before 5am.
Lancashire Fire and Rescue Service also sent a Stinger high pressure unit from Blackburn and a control unit to the site which is near to the M6.
Warning signs for smoke were set on the motorway between junctions 31 and 31A and officers also reported smoke drifting across the B6243 Longridge Road causing traffic to slow down.
A fire brigade spokesman said: "We were called at 4.52am to a large fire at a recyling centre on the Red Scar Business Park.
"Six fire engines attended as well as the Stinger unit from Blackburn.
"The fire is in a unit measuring approximately 25 metres by 25 metres containing recyclable waste of unknown properties.
"The incident is now under control and we have reduced the number of crews to three. They are just damping down and checking for hotspots.
"It is too early at this stage to say what the cause is. There will be an investigation, but there is nothing at the moment to suggest it was deliberate."