The M65 was closed between junction 7 and 8 after a huge fire involving over 400 scrap cars.
Fire crews from across Lancashire were called out to the car salvage yard/scrapyard on Burnley Road, Altham following the initial reports of the blaze just before 4.45am on Wednesday.
Lancashire Fire and Rescue said they now have 90 firefighters on the site, which has in total around 2,000 cars, tackling the fire which spread quickly assisted by a “strong breeze".
A spokesperson added: “Crews are being supported by a high volume pump which is bringing additional water to the site and a hazardous materials unit which is providing specialist support and advice on protecting the environment and public health.
"There is a significant smoke plume and residents are asked to keep their doors and windows closed. People are asked to avoid the area and to take care if travelling in the vicinity.”
Hyndburn Police said it was going to be a protracted incident while this blaze is brought under control, launching Operation Merlin.
In a statement on their Facebook page, they said: "Smoke is causing issues for road users in the area, particularly the M65. We urge drivers to take extra care and travel at a safe speed for the conditions they find themselves in.
"Residents in the area may hear loud bangs and explosions, please be assured Lancashire Fire and Rescue are working as hard as they can to ensure the area is made as safe as possible."
They added: "We have currently closed access to the Moorfield Industrial Estate. If you work on this estate we suggest you speak to your employer before attending your workplace to avoid congestion in the area."
Earlier this morning, motorway police also had to deal with a Road Traffic Collision next to the fire on the M65 between Junctions 7 and 8 on the eastbound carriageway.