ARSONISTS set fire to a car parked next to a huge store room at Colne Valley Business Park, Linthwaite.
Fire crews called to the blaze at the vast former mill said they tackled it just in time.
The incident happened at about 11.55pm last night.
Huddersfield and Slaithwaite fire crews called to the premises initially treated the job as a building fire.
But they quickly found the flaming car at the rear of the site.
The flames had ignited a boarded-up window and then spread inside.
Slaithwaite fire station Sub Officer Howard Young said: "The fire must have been going a while because the car was almost burnt out.
"It is a massive mill complex so it was lucky we got there in time. The unit was storing all combustibles."