Five people have been arrested over a huge blaze at a historic mill building in Keighley which has featured in hit TV shows including Peaky Blinders and Downton Abbey.
Police say they are treating the incident at the Grade II listed Dalton Mills as arson.
West Yorkshire Fire and Rescue Service says the incident has now been scaled back, with one fire engine and one aerial appliance at the scene.
The service said on Thursday afternoon the building was unsafe and there was a risk of it collapsing.
Incident Commander Nicholas Smith said: "The building is unsafe, there is a risk of collapse, the floors and the roof are no longer in place so now we're just going to be fully extinguishing the fire and stopping it spreading any further."
The fire service has thanked local residents in the area and partner agencies for their support.
A cordon is still in place, with Dalton Lane closed to traffic between School Lane and Riverside.
Bradford Council said businesses nearby needed to speak to the officer on the cordon get access to their buildings.
Police are appealing for witnesses who saw anything suspicious in the area between 11.30am and 12pm on Thursday afternoon and anyone with dashcam footage.