Fire crews are battling a blaze that's engulfed a boarding house and spread to a commercial building at South Brisbane.
The fire started in the Vulture Street boarding house about 6am and spread to a neighbouring commercial property.
Police say all residents of the eight-room boarding house have been accounted for.
About 30 residents from a nearby nursing home have been evacuated but about 40 others remain inside, with precautions taken to stop thick smoke from entering, Police Inspector Steve Flori said.
He said the boarding house would have to be demolished. The ABC said the property was heritage listed.
"We're very lucky there's been no one caught (inside)," Insp Flori told reporters.
"We don't know the cause of the fire at this point in time," he added, but it's believed to have started inside one of the units.
An exclusion zone has been set up around the fire scene, and Vulture Street his closed.