At 4:19am today, a fire broke out in the upper floors of an apartment building at 555 Clayton St. (at Haight), directly across from the Clayton Street post office.

One person in the building suffered a moderate injury related to smoke inhalation and was transported to St. Francis Burn Center, said Jonathan Baxter, a representative for the Fire Department. It's currently unclear if anyone in the building has been displaced.

The fire was under control by 4:44am, and a passerby said that while SFFD initially intended to provide a Muni bus to keep the evacuated residents warm, they never needed it—residents were allowed back inside the building by 5:20am.

The cause of the fire is currently under investigation, Baxter said. 

A video of the fire, below, was taken by tipster Jeremy B.