Firefighters are tackling a blaze involving 400 vehicles in an industrial estate.
Crews were called at about 05:45 GMT to the fire in Wigan, Greater Manchester Fire and Rescue Service (GMFRS) said. No one is reported to be injured.
Station Manager Andy Hardman said firefighters had “scaled back the incident significantly” at Kirkless Industrial Estate.
“Our crews continue to work extremely hard to extinguish this fire.”
He advised local residents to keep windows and doors shut.
There are no details yet on the cause of the blaze.