ARSONISTS targeted a derelict mill twice during the weekend.
Fire broke out at Highfield Mills in Staincliffe, Batley, at 11.12pm on Saturday night.
Two fire crews from Dewsbury and one from Batley went to the scene.
An aerial appliance from Huddersfield was also called out.
Firefighters found a 20-metre by 30-metre section of the three- storey mill on fire.
They tackled the blaze with two large water jets.
Four firefighters wearing breathing apparatus used a thermal imaging camera to check for hotspots.
No-one was injured.
Then just after 4am on Sunday crews were again called to the site after reports of a fire.
They found part of the building ablaze.
Two fire crews from Dewsbury, one from Wakefield and one from Bradford fought the flames.
The fire was contained just over an hour later. Crews spent the rest of the night there damping down the site.
Watch Manager Peter Lau said the building was already partly demolished before the fires.
He added: "The second fire was set on the third floor.
"Whoever did this not only risked their lives, but our lives, too.
"The building is very unsafe."