Firefighters have warned the public to stay away from the "extremely dangerous" blaze.
I'm trapped in an unsellable, uninsurable home, paying thousands to fix fire safety defects I played no part in creating.
West Midlands Fire Service urged people near the Tyseley estate to keep doors and windows shut.
A prosecutor confirmed the incident is being treated as a "criminal act", but gave no further details.
Eight fire engines have been dispatched to the building on Childers Street.
In the midst of the worst bushfire season in living memory, parts of south east Australia have been hit by flash flooding, golf ball sized hail, and large dust storms.
Police were called to a fire in Ceredigion, western Wales, in the early hours of Sunday.
New Year’s Eve fireworks may have started the blaze.
The Scottish Fire and Rescue Service said a “well-developed” fire started within the second floor of the building.
Many of the victims were labourers sleeping above the factory, according to local media reports.