“All smoke is poisonous and dangerous. Close all the windows and doors and stay inside if it is possible,” said Robert Eriksson of the Stockholm fire brigade to the TT news agency.
The fire, which started on a balcony in Skarpnäck on Thursday morning, spread throughout a set of apartment blocks, with emergency services fighting until after midday to extinguish the flames.
The fire broke out around 7am, however no one was in the flat at the time, and no one has been injured seriously.
40 people have been evacuated from their homes, most of whom are taking shelter at a local high school as the smoke continues to spread.
The fire spread through the attics of the apartment block, eventually damaging the roof and attic beyond repair.
Thirteen ambulances and thirteen fire engines were on the scene throughout the morning, as well as one ambulance helicopter.