About 60 firefighters have tackled a fire at a textile factory in the Sparkbrook area of Birmingham.
It started at about 1015 GMT in Stratford Road. No-one was hurt but part of the building collapsed, West Midlands Fire Service said.
Stratford Road remains closed from Warwick Road and Fulham Road while fire crews ensure the safety of the buildings nearby.
Up to 40 firms have been unable to open as a result of the fire disruption.
Bus routes have also been affected.
A fire service spokesman said crews were likely to remain at the scene overnight while investigations into the cause of the blaze continue.
He added a demolition company would be assessing the stability of the building to see if any action needed to be taken.